WorldWideScience

Sample records for basin southern peru

  1. Andes hantavirus variant in rodents, southern Amazon Basin, Peru.

    Science.gov (United States)

    Razuri, Hugo; Tokarz, Rafal; Ghersi, Bruno M; Salmon-Mulanovich, Gabriela; Guezala, M Claudia; Albujar, Christian; Mendoza, A Patricia; Tinoco, Yeny O; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah; Nichol, Stuart T; Hirschberg, David L; Lipkin, W Ian; Bausch, Daniel G; Montgomery, Joel M

    2014-02-01

    We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.

  2. Oligocene-Miocene deformational and depositional history of the Andean hinterland basin in the northern Altiplano plateau, southern Peru

    Science.gov (United States)

    Perez, Nicholas D.; Horton, Brian K.

    2014-09-01

    Cenozoic basin fill of the northern Altiplano plateau records the tectonic development of the flanking Western Cordillera magmatic arc and Eastern Cordillera fold-thrust belt. The Ayaviri hinterland basin of southern Peru contains a ~2300 m thick succession of fluvial sandstones and overbank siltstones (upper Oligocene Puno Group and lower Miocene lower Tinajani Formation) capped by ~400 m of alluvial fan conglomerates (middle Miocene upper Tinajani Formation). New U-Pb zircon chronostratigraphic constraints from ~30 to 15 Ma yield sediment accumulation rates of 110-660 m/Myr. Newly dated growth strata highlight the genetic role played by thrust displacement in basin evolution. A several phase accumulation history derived from chronostratigraphic, provenance, and structural data reveals Oligocene basin filling by fluvial sand and mud that changes provenance from Western Cordillera Mesozoic-Cenozoic volcanic rocks to Paleozoic-Mesozoic Eastern Cordillera sedimentary rocks driven by deformation along the southwest directed, northeastern basin margin Ayaviri thrust at 28-26 Ma. Continued early Miocene fluvial deposition was sourced solely from the Eastern Cordillera. An abrupt middle Miocene shift to coarse alluvial fan deposition sourced from the Western Cordillera was driven by out-of-sequence deformation along the northeast directed, southwestern basin margin Pasani thrust at 18-16 Ma. This northern Altiplano out-of-sequence deformation was coincident with increased Eastern and Western Cordillera exhumation and thrusting and may be symptomatic of changes in critical wedge dynamics. The overall record of basin sedimentation and syndepositional fold-thrust deformation emphasizes the role of regional shortening in governing crustal thickening and basin evolution in the central Andes during the Oligocene to Miocene.

  3. Paleogeographic and tectonic controls on the evolution of Cenozoic basins in the Altiplano and Western Cordillera of southern Peru

    Science.gov (United States)

    Carlotto, Víctor

    2013-03-01

    Integrated studies of stratigraphy, sedimentology, paleogeography and tectonic controls on Cenozoic basins provide the basis for a series of time-slice reconstructions of basin evolution in the Andes of southern Peru. The Altiplano and adjacent margin of the Western Cordillera are characterized by several Paleocene-Miocene synorogenic continental basins with thicknesses locally exceeding 10 km. The evolution of these basins has been controlled by NW-trending tectonic features that mark the Altiplano-Western Cordillera and Altiplano-Eastern Cordillera boundaries and the Condoroma structural high. Sedimentary deposits of Paleocene age preserved in the Altiplano are the result of nonmarine sedimentation in a distal foreland basin. During the early Eocene, predominantly dextral strike-slip movements in the Altiplano between the Cusco-Lagunillas and Urcos-Ayaviri fault systems created the transpressional Kayra basin. The Soncco and Anta basins (middle Eocene-early Oligocene) are related to NE shortening (43-30 Ma) and represent proximal, wedge-top and foredeep basin environments preserved on the Altiplano. At ~ 29-28 Ma, a change to predominantly E-W shortening produced sinistral strike-slip motion along NW-striking faults, resulting in intermontane, transpressional basins. In the Altiplano, the Tinajani and Punacancha (29-5 Ma), and Paruro (12-6 Ma) basins were controlled by the Cusco-Lagunillas and the Urcos-Ayaviri fault systems. The Maure, Tincopalca-Huacochullo and Condoroma basins (22-5 Ma) of the Western Cordillera developed between the Condoroma high and the Cusco-Lagunillas fault system. Oligocene-Miocene sedimentation commonly evolved from proximal (alluvial) facies along the borders to distal (lacustrine) facies. These basins were linked to sinistral strike-slip faults that evolved into reverse-sinistral structures. Plate kinematics may play a role in Andean basin evolution, with deformation influenced by major preexisting faults that dictated paleogeographic

  4. Geodynamic Drivers of Vertical Crustal Motion: Integrating Paleoaltimetry with Basin Development in the Central Andean Plateau of Southern Peru

    Science.gov (United States)

    Sundell, K. E., II; Saylor, J. E.; Lapen, T. J.; Villarreal, D. P.; Styron, R. H.; Horton, B. K.; Cardenas, J.

    2015-12-01

    Determining the spatial and temporal relationships between surface uplift, tectonic subsidence, and exhumation during periods of oblique crustal shortening is essential to discriminating geodynamic processes controlling formation of high topography in the central Andes. Although subsidence analysis is now a standard tool, paleoelevation estimation remains a challenging task, as estimates based on proxy data can be complicated by uncertainties in the relative controls of tectonics and climate. We therefore adopt an approach of combining established tools of subsidence analysis and detrital geochronology with emerging methods of volcanic glass paleoaltimetry, which enables us to explore a broad range of viable interpretations to understand the development of intermontane basins and their relationship to the development of the central Andean plateau. We investigated a suite of temporally overlapping and spatially separate Cenozoic basins spanning the east-west extent of the central Andean plateau in southern Peru. These basins contain an exceptional record of the vertical movements of this region. We calculate sediment accumulation and subsidence rates through decompaction of measured stratigraphic sections, and reconstruct past environmental conditions based on the stable isotopic composition of ancient waters preserved in hydrated volcanic glass. These data and published records of crustal shortening and exhumation show that although paleoaltimetry data in the study areas may be interpreted in various ways, they are best explained by multiple geodynamic processes driving (i) Eocene-early Miocene development of high topography in the Western Cordillera, then (ii) a pulsed middle Miocene-present building of the central Andean plateau from west to east, consistent with global climate changes as well as regional climate shifts driven by topographic development of the Andean orogen.

  5. Fibrous gypsum veins as diffuse features and within fault zones: the case study of the Pisco Basin (Ica desert, southern Peru)

    Science.gov (United States)

    Rustichelli, Andrea; Di Celma, Claudio; Tondi, Emanuele; Baud, Patrick; Vinciguerra, Sergio

    2016-04-01

    New knowledge on patterns of fibrous gypsum veins, their genetic mechanisms, deformation style and weathering are provided by a field- and laboratory-based study carried out on the Neogene to Quaternary Pisco Basin sedimentary strata (porous sandstones, siltstones and diatomites) exposed in the Ica desert, southern Peru. Gypsum veins vary considerably in dimensions, attitudes and timing and can develop in layered and moderately fractured rocks also in the absence of evaporitic layers. Veins occur both as diffuse features, confined to certain stratigraphic levels, and localised within fault zones. Arrays formed by layer-bounded, mutually orthogonal sets of steeply-dipping gypsum veins are reported for the first time. Vein length, height and spacing depend on the thickness of the bed packages in which they are confined. Within fault zones, veins are partly a product of faulting but also inherited layer-bounded features along which faults are superimposed. Due to the different petrophysical properties with respect to the parent rocks and their susceptibility to textural and mineralogical modifications, water dissolution and rupture, gypsum veins may have a significant role in geofluid management. Depending on their patterns and grade of physical and chemical alteration, veins may influence geofluid circulation and storage, acting as barriers to flow and possibly also as conduits.

  6. Multi-method provenance model for early Paleozoic sedimentary basins of southern Peru and northern Bolivia (13°-18°S)

    Science.gov (United States)

    Reimann Zumsprekel, Cornelia R.; Bahlburg, Heinrich; Carlotto, Victor; Boekhout, Flora; Berndt, Jasper; Lopez, Shirley

    2015-12-01

    In early Paleozoic time the Peru-Bolivia Trough at the South American Gondwana margin accommodated large volumes of siliciclastic detritus of hitherto largely unknown provenance. A multi-method provenance study of framework components, heavy minerals and whole rock geochemistry of Ordovician to Devonian formations of southern Peru and northern Bolivia reveals the predominant contribution from upper crustal sources. Main heavy minerals include zircon, tourmaline, rutile, apatite, garnet, epidote, monazite, and titanite and are strongly biased diagenetically towards the stable phases. Electron microprobe single grain analysis of tourmaline and rutile indicate that detrital tourmalines were derived mainly from metasedimentary, and subordinately, from granitic sources. Cr/Nb ratios in rutiles point to a metamafic derivation for 20-40% of grains, the remainder originating in felsic lithologies. Zr in rutile thermometry indicates a provenance from relatively high-grade metamorphic rocks transformed at temperatures between 500 °C and 900 °C, with clusters at c. 600 °C, 700 °C and 800 °C. U-Pb geochronological analysis of rutiles was largely unsuccessful due to high concentrations of common Pb. Three ages could be obtained and fall between 525 and 545 Ma, probably linking this detritus to the hidden Neoproterozoic orogen in what are now Cordillera Oriental and Sierras Subandinas. The most notable feature of the whole rock geochemical data is a high Cr content in the majority of samples, which otherwise have a composition similar to weathered upper continental crust. The elevated Cr contents indicates that ophiolitic rocks were either exposed to erosion abundantly in the source areas or had previously supplied significant volumes of detritus to intermittent sediment storage systems now eroded into the studied sedimentary rocks. Potential source candidates include the Ordovician metamorphic Tapo Ultramafic Complex in the Cordillera Oriental of central Peru, and the

  7. Staphylococcus aureus causing tropical pyomyositis, Amazon Basin, Peru.

    NARCIS (Netherlands)

    Garcia, C.; Hallin, M.; Deplano, A.; Denis, O.; Sihuincha, M.; Groot, R. de; Gotuzzo, E.; Jacobs, J.

    2013-01-01

    We studied 12 Staphylococcus aureus isolates causing tropical pyomyositis in the Amazon Basin of Peru. All isolates were methicillin-susceptible; 11 carried Panton-Valentine leukocidin-encoding genes, and 5 belonged to multilocus sequence type 25 and possessed an extensive set of enterotoxins. Our f

  8. Crustal Seismicity and Recent Faults in Southern Peru

    Science.gov (United States)

    David, C.; Comte, D.; Tavera, H.; Audin, L.; Herail, G.

    2004-12-01

    Most seismological studies in southern Peru have been focused on the downgoing slab seismicity in order to constrain the Wadati-Benioff zone. This study deals with the intra-continental seismicity of the southern Peru forearc (17,3° S - 18,5° S) in a post-seismic context (Arequipa thrust earthquake, Mw=8.4, 23 June, 2001). It is difficult to identify historical crustal earthquake from available catalogues, however some crustal events teleseismically recorded can be found since 1976; they exhibit normal focal mechanism solutions in the southern Peru volcanic arc and inverse focal mechanism solutions in the Central Depression. Following a notable increase of shallow crustal seismicity located close to the Western Cordillera after the 23 June 2001, a temporary seismic network was deployed between January and March 2003 in order to study the Wadati-Benioff zone and monitoring the crustal seismicity in southern Peru. From the about 1700 events locally recorded by the local network, 300 crustal earthquakes were identified in the Peruvian forearc between Tacna and Moquegua. This crustal seismicity is distributed along a lineament located at depths between 0 and 60 km, dipping at about 45° from the Western Cordillera towards the coast, almost perpendicular to the subducting slab; this behaviour was previously observed in northern Chile and in southern Peru, north of the study zone (16° S). In the Central Depression, seismic activity is not superficial occurring between 25-60 km depth and it is mostly characterized by inverse focal mechanism solutions. Superficial faults situated in the Central Depression and in the Coastal Cordillera can not be associated with the seismic activity observed in this area. However, in the Pre-Cordillera, crustal seismicity occurs at depths between 0-15 km and can be correlated with shallow fault systems recognized by satellite images and on the field. For examples, the Incapuquio fault system which was a transpressive system in Cretaceous

  9. Additions of angiosperms to the Flora of Peru from the Andean-Amazonian forests of southern Peru

    Directory of Open Access Journals (Sweden)

    Isau Huamantupa

    2014-10-01

    Full Text Available We present 25 new records of angiosperms for the Peruvian flora, as a result of different botanical explorations conducted in southern Peru, mainly in the areas of the departments of Cusco, Apurimac and Madre de Dios.

  10. The formation of early settled villages and the emergence of leadership: A test of three theoretical models in the Rio Ilave, Lake Titicaca Basin, southern Peru

    Science.gov (United States)

    Craig, Nathan Mcdonald

    Despite obvious necessities for understanding later developments in the region, Preceramic cultures in the Titicaca Basin are poorly understood due to lacking empirical data. This dissertation focuses on examination of two processes occurring in the Rio Ilave drainage during the Late 5000--3100 B.C.E. (6000--4400 B.P.) and Terminal 3100--1500 B.C.E. Archaic (4400--3200 B.P.): the formation of settled villages and the emergence of leadership. These processes are tested against theoretical predictions derived from: population resource imbalance, human behavioral ecology, and agency theories. Resource imbalance theory predicts appearance of density dependent adaptive problems prior to major cultural transformations. Human behavioral ecology predicts increased dietary diversity and incorporation of greater processing costs occuring coincidentally with reduced residential mobility. Symbolic mate value advertising is a predicted leadership strategy. Agency theory predicts internal sources of social tension, potentially independent of external forces, as primary causes of cultural change. Feast hosting and the formation political economy are expected to be central to both social processes investigated from this perspective. Local paleoclimatic proxies suggest aridity from ca 4000--2000 B.C.E. Reanalysis of pedestrian survey data indicate population growth during the Late Archaic. Excavation and ground penetrating radar survey at Pirco and Jiskairumoko demonstrate reduced residential mobility and increased evidence for social differentiation appearing during the Late Archaic's (before 3000 B.C.E.) end. New cultural patterns include: pithouses, more groundstone, internal storage, costly non-local artifacts, domesticated plants and animals, costly grave goods, and use of ochre in symbolic contexts. No clear cut evidence for inter-community promotional feasting was identified but some finds suggest intra-community alliance feasts. By the end of the Terminal Archaic ca. 1500 B

  11. Avifauna of the Pongos Basin, Amazonas Department, Peru

    Science.gov (United States)

    Brooks, D.M.; O'Neill, J.P.; Foster, M.S.; Mark, T.; Dauphine, N.; Franke, I.J.

    2009-01-01

    We provide an inventory of the avifauna of the Pongos Basin, northern Amazonas Department, Peru based on museum specimens collected during expeditions spanning >60 years within the 20th century. Four hundred and thirty-eight species representing 52 families are reported. Differences between lowland and higher elevation avifaunas were apparent. Species accounts with overviews of specimen data are provided for four species representing distributional records, two threatened species, and 26 species of Nearctic and Austral migrants, of which six are considered probable migrants.

  12. Peru

    OpenAIRE

    World Bank Group

    2014-01-01

    The Country Opinion Survey in Peru assists the World Bank Group (WBG) in gaining a better understanding of how stakeholders in Peru perceive the WBG. It provides the WBG with systematic feedback from national and local governments, multilateral/bilateral agencies, media, academia, the private sector, and civil society in Peru on 1) their views regarding the general environment in Peru; 2) ...

  13. Islay And The Economy Of Southern Peru In 19th Century

    OpenAIRE

    Bonilla, Heraclio

    2015-01-01

    This article notes the specificity of the regional economic history of Southern Peru, which in 1780-1840 experienced an important economic growth while the rest of the Viceroyalty of Peru was in crisis. This important fact is not well known because of the lack of research on regional economy. It presents data on the dynamics of international markets and its relation with the southern economy. Finally, the article argues some problems related to the general development of the Peruvian economy.

  14. Shadows of the colonial past – diverging plant use in Northern Peru and Southern Ecuador

    OpenAIRE

    Bussmann Rainer W; Sharon Douglas

    2009-01-01

    Abstract This paper examines the traditional use of medicinal plants in Northern Peru and Southern Ecuador, with special focus on the Departments of Piura, Lambayeque, La Libertad, Cajamarca, and San Martin, and in Loja province, with special focus on the development since the early colonial period. Northern Peru represents the locus of the old Central Andean "Health Axis." The roots of traditional healing practices in this region go as far back as the Cupisnique culture early in the first mi...

  15. High Andean butterflies from southern Peru, I. Dry puna Satyrinae, with the description of two new taxa and three new records from Peru (Lepidoptera: Nymphalidae

    Directory of Open Access Journals (Sweden)

    José Alfredo Cerdeña

    2014-12-01

    Full Text Available This is the first part of a series of contributions to the knowledge of the high Andean butterfly fauna in southern Peru. In this work the butterfly species of the subfamily Satyrinae present in the dry puna of Peru are reviewed. A new species, Pampasatyrus gorkyi sp. nov. and a new subspecies Argyrophorus lamna cuzcoensis ssp. nov. are described from the department Cusco, Peru. Three species are recorded for the first time for Peru, Argyrophorus gustavi Staudinger, Faunula euripides (Weymer and Faunula eleates (Weymer previously reported from Chile and Bolivia. Ecological and biogeographical data are provided.

  16. Peru.

    Science.gov (United States)

    1987-12-01

    This publication provides a brief account of Peru's geographic, history, government, and political and economic conditions. With an area of 1.28 million sq. km., Peru is the third largest country in South American and is home to 20.2 million inhabitants (6 million live in the capital city of Lima). The population is 45% Indian, 37% mestizo, 15% white, and 3% black, Asian, and other. The 2 official languages are Spanish and Quechua. Its literacy rate stands at 79%, and its infant mortality rate and life expectancy measure 91/1000 and 60.8 years respectively. Peru's pre-Colombian period notes the impressive achievements of the Inca civilization, which was conquered by Spain in 1531. The country gained its independence from Spanish rule in 1821. The article also mentions Peru's turbulent contemporary history, with territorial disputes, a strong military presence, and a series of coups that have interrupted civilian constitutional governments. As recently as 1985, Peru had its first exchange of power from 1 democratically elected leader to another in 40 years, when 36 year-old Alan Garcia Perez became president. Leader of the American Popular Revolutionary Alliance (APRA), GArcia espouses leftist but not non-communist politics, and is well-known for his message of anti-imperialism and Latin American integration. Peru's has seen terrorist activity from 2 marxist organizations, the Maoist Sendero Luminoso (The Shining Path) and the MRTA-MIR (Tupac Amaru Revolutionary Movement-Movement of the Revolutionary Left. In 1986, Peru's economy had a $17 billion Gross Domestic Product (GDP), a per capital GDP of $839, and an inflation rate of 62.9. The article also provides information concerning US economic assistance to Peru, as well as an assessment of US-Peruvian relations. PMID:12178073

  17. Mummies and dental health in the ancient Ilo valley, southern Peru

    Directory of Open Access Journals (Sweden)

    Simon Hillson

    2003-10-01

    Full Text Available In the very arid climate of southern Peru, archaeological remains, including many human burials, are extremely well preserved. Study of the teeth of mummified people from different cultural groups and time periods is beginning to provide evidence of diet and disease among the ancient inhabitants of the Ilo valley between the foot-hills of the Andes and the desert coast.

  18. Origin of lead in andean calc-alkaline lavas, southern peru.

    Science.gov (United States)

    Tilton, G R; Barreiro, B A

    1980-12-12

    Lead isotope data from Quaternary andesitic lavas of the Arequipa and Barroso groups of southern Peru and from regional Precambrian granulitic gneisses reveal a lead component in the lavas from the gneisses. The lava leads can be accounted for by two-component mixtures of lead from mantle and lower crustal sources, although the mixing process need not have occurred in the lower crust.

  19. Multiple glacial culminations from the Lateglacial to the late Holocene in central and southern Peru (Invited)

    Science.gov (United States)

    Licciardi, J. M.; Schaefer, J. M.; Rodbell, D. T.; Stansell, N.; Schweinsberg, A.; Finkel, R. C.; Zimmerman, S. R.

    2013-12-01

    Fluctuations in small tropical mountain glaciers serve as sensitive indicators of variations in past and present-day climate. Most of the world's modern tropical glaciers reside in the Peruvian Andes, where a growing number of well-dated glacial records have recently been developed. As additional records are documented, regional patterns of late Pleistocene to Holocene glacial activity have begun to emerge. Here we present a compilation of new and previously obtained 10Be surface exposure ages from boulders on well-preserved moraine successions in two glaciated Andean ranges: the Cordillera Vilcabamba of southern Peru (13°20'S, 72°32'W) and the Huaguruncho massif (10°32'S, 75°56'W), located in central Peru ~450 km northwest of the Vilcabamba. A high-resolution composite chronology that merges >100 10Be measurements on moraine sequences in five glaciated drainages of the Cordillera Vilcabamba reveals the occurrence of at least five discrete glacial culminations from the Lateglacial to the late Holocene. At the Huaguruncho massif, >20 10Be exposure ages obtained from moraine sequences in a south-facing cirque indicate at least three major glacial stages spanning the Lateglacial to the Little Ice Age. The moraine ages at Huaguruncho are broadly correlative with the Vilcabamba moraine chronologies, with some dated moraine belts exhibiting geomorphic expressions that closely resemble those of their coeval counterparts in the Vilcabamba. A recurring finding in both field areas is a mismatch between basal radiocarbon ages from bog and lake sediments and 10Be exposure ages on outboard moraines, which enclose the depositional basins. These age discrepancies suggest that cosmogenic 10Be production rates scaled to high altitudes in the tropics are substantially lower than previous estimates. While we anticipate that future refinements to scaled isotope production rates may significantly affect correlation of 10Be exposure ages in the high Andes with ages derived from

  20. Shadows of the colonial past – diverging plant use in Northern Peru and Southern Ecuador

    Directory of Open Access Journals (Sweden)

    Bussmann Rainer W

    2009-02-01

    Full Text Available Abstract This paper examines the traditional use of medicinal plants in Northern Peru and Southern Ecuador, with special focus on the Departments of Piura, Lambayeque, La Libertad, Cajamarca, and San Martin, and in Loja province, with special focus on the development since the early colonial period. Northern Peru represents the locus of the old Central Andean "Health Axis." The roots of traditional healing practices in this region go as far back as the Cupisnique culture early in the first millennium BC. Northern Peru and Southern Ecuador share the same cultural context and flora but show striking differences in plant use and traditional knowledge. Two hundred fifteen plant species used for medicinal purposes in Ecuador and 510 plant species used for medicinal purposes in Peru were collected, identified,. and their vernacular names, traditional uses, and applications recorded. This number of species indicates that the healers, market vendors, and members of the public interviewed in Peru still have a very high knowledge of plants in their surroundings, which can be seen as a reflection of the knowledge of the population in general. In Ecuador much of the original plant knowledge has already been lost. In Peru, 433 (85% were Dicotyledons, 46 (9% Monocotyledons, 21 (4% Pteridophytes, and 5 (1% Gymnosperms. Three species of Giartina (Algae and one species of the Lichen genus Siphula were used. The families best represented were Asteraceae with 69 species, Fabaceae (35, Lamiaceae (25, and Solanaceae (21. Euphorbiaceae had 12 species, and Poaceae and Apiaceae each accounted for 11 species. In Ecuador the families best represented were Asteraceae (32 species, Euphorbiaceae, Lamiaceae, and Solanaceae (11 species each, and Apiaceae, Fabaceae, Lycopodiaceae (9 species each. One hundred eighty-two (85% of the species used were Dicotyledons, 20 Monocotyledons (9.3%, 12 ferns (5.5%, and one unidentified lichen was used. Most of the plants used (83% were

  1. Shadows of the colonial past--diverging plant use in Northern Peru and Southern Ecuador.

    Science.gov (United States)

    Bussmann, Rainer W; Sharon, Douglas

    2009-02-02

    This paper examines the traditional use of medicinal plants in Northern Peru and Southern Ecuador, with special focus on the Departments of Piura, Lambayeque, La Libertad, Cajamarca, and San Martin, and in Loja province, with special focus on the development since the early colonial period. Northern Peru represents the locus of the old Central Andean "Health Axis." The roots of traditional healing practices in this region go as far back as the Cupisnique culture early in the first millennium BC. Northern Peru and Southern Ecuador share the same cultural context and flora but show striking differences in plant use and traditional knowledge. Two hundred fifteen plant species used for medicinal purposes in Ecuador and 510 plant species used for medicinal purposes in Peru were collected, identified,. and their vernacular names, traditional uses, and applications recorded. This number of species indicates that the healers, market vendors, and members of the public interviewed in Peru still have a very high knowledge of plants in their surroundings, which can be seen as a reflection of the knowledge of the population in general. In Ecuador much of the original plant knowledge has already been lost. In Peru, 433 (85%) were Dicotyledons, 46 (9%) Monocotyledons, 21 (4%) Pteridophytes, and 5 (1%) Gymnosperms. Three species of Giartina (Algae) and one species of the Lichen genus Siphula were used. The families best represented were Asteraceae with 69 species, Fabaceae (35), Lamiaceae (25), and Solanaceae (21). Euphorbiaceae had 12 species, and Poaceae and Apiaceae each accounted for 11 species. In Ecuador the families best represented were Asteraceae (32 species), Euphorbiaceae, Lamiaceae, and Solanaceae (11 species each), and Apiaceae, Fabaceae, Lycopodiaceae (9 species each). One hundred eighty-two (85%) of the species used were Dicotyledons, 20 Monocotyledons (9.3%), 12 ferns (5.5%), and one unidentified lichen was used. Most of the plants used (83%) were native to Peru

  2. Mammal diversity in the middle basin of the river Tambopata, Puno, Peru

    Directory of Open Access Journals (Sweden)

    Víctor Pacheco

    2011-08-01

    Full Text Available This study documents the mammalian diversity in the Tambopata River middle basin, one of the most important information gaps in Peru. Five sites were evaluated in Puno (San Fermín 850 m, Curva Alegre 950 m, Challohuma 1200 m, Yanahuaya 1600 m, and Yanacocha 1985 m. The trapping effort was 7072 trap-nights and 201 mistnet-nights. 76 species were recorded in the study area, including 16 species under some conservation’s category. Bats and rodents were the most diverse orders (67.5%. The diversity indices of Shannon-Wiener and Simpson for small mammals show a moderate and mild negative correlation with elevation, respectively. Meanwhile the altitude is negatively correlated with the relative abundance (RA of bats, and positively with the RA of non-volant mammals. The marsupials Marmosa (Micoureus demerarae, Marmosops bishopi and Marmosops impavidus; the rodent Neacomys musseri, and bats Platyrrhinus albericoi, P. masu, P. nigellus, Eumops auripendulus and Cormura brevirostris are first records for the department of Puno. Akodon baliolus and Oxymycterus juliacae are considered valid species. The species Sturnira lilium and Akodon baliolus were those with the highest RA. Our records, added to published and unpublished data, indicate that the Río Tambopata watershed is habitat of 141 species of mammals. Finally, we recommend the extension of the southern part of the buffer zone of the PNBS to include the montane forests of Yanacocha, to protect the unique middleelevation fauna of the Río Tambopata watershed.

  3. Climate change underlies global demographic, genetic, and cultural transitions in pre-Columbian southern Peru.

    Science.gov (United States)

    Fehren-Schmitz, Lars; Haak, Wolfgang; Mächtle, Bertil; Masch, Florian; Llamas, Bastien; Cagigao, Elsa Tomasto; Sossna, Volker; Schittek, Karsten; Isla Cuadrado, Johny; Eitel, Bernhard; Reindel, Markus

    2014-07-01

    Several archaeological studies in the Central Andes have pointed at the temporal coincidence of climatic fluctuations (both long- and short-term) and episodes of cultural transition and changes of socioeconomic structures throughout the pre-Columbian period. Although most scholars explain the connection between environmental and cultural changes by the impact of climatic alterations on the capacities of the ecosystems inhabited by pre-Columbian cultures, direct evidence for assumed demographic consequences is missing so far. In this study, we address directly the impact of climatic changes on the spatial population dynamics of the Central Andes. We use a large dataset of pre-Columbian mitochondrial DNA sequences from the northern Rio Grande de Nasca drainage (RGND) in southern Peru, dating from ∼840 BC to 1450 AD. Alternative demographic scenarios are tested using Bayesian serial coalescent simulations in an approximate Bayesian computational framework. Our results indicate migrations from the lower coastal valleys of southern Peru into the Andean highlands coincident with increasing climate variability at the end of the Nasca culture at ∼640 AD. We also find support for a back-migration from the highlands to the coast coincident with droughts in the southeastern Andean highlands and improvement of climatic conditions on the coast after the decline of the Wari and Tiwanaku empires (∼1200 AD), leading to a genetic homogenization in the RGND and probably southern Peru as a whole. PMID:24979787

  4. Analysis of the 23 June 2001 Southern Peru Earthquake Using Locally Recorded Seismic Data

    Science.gov (United States)

    Tavera, H.; Comte, D.; Boroschek, R.; Dorbath, L.; Portugal, D.; Haessler, H.; Montes, H.; Bernal, I.; Antayhua, Y.; Salas, H.; Inza, A.; Rodriguez, S.; Glass, B.; Correa, E.; Balmaceda, I.; Meneses, C.

    2001-12-01

    The 23 June 2001, Mw=8.4 southern Peru earthquake ruptured the northern and central part of the previous large earthquake occurred on 13 August 1868, Mw ~9. A detailed analysis of the aftershock sequence was possible due to the deployment of a temporary seismic network along the coast in the Arequipa and Moquegua districts, complementing the Peruvian permanent stations. The deployed temporary network included 10 short period three component stations from the U. of Chile-IRD-France and 7 broad-band seismic stations from the Instituto Geofísico del Perú. This network operated during the first weeks after the mainshock and recorded the major aftershocks like the larger one occurred on 7 July 2001, Mw=7.5, this event defines the southern limit of the rupture area of the 2001 Peruvian earthquake. The majority of the aftershocks shows a thrusting fault focal mechanisms according with the average convergence direction of the subducting Nazca plate, however, normal faulting events are also present in the aftershock sequence like the 5 July 2001, Mw=6.6 one. The depth distribution of the events permitted a detailed definition of the Wadati-Benioff zone in the region. The segment between Ilo and Tacna did not participated in the rupture process of the 2001 southern Peru earthquake. Seismicity located near the political Peruvian-Chilean boundary was reliable determined using the data recorded by the northern Chile permanent network. Analysis of the mainshock and aftershock acelerograms recorded in Arica, northern Chile are also included. The occurrence of the 1995 Antofagasta (Mw=8.0) and the 2001 southern Peru earthquakes suggests that the probability of having a major earthquake in the northern Chile region increased, considering that the previous large earthquake in this region happened in 1877 (Mw ~9), and since that time no earthquake with magnitude Mw>8 had occurred inside of the 1877 estimated rupture area (between Arica and Antofagasta).

  5. Stress in the contorted Nazca Plate beneath southern Peru from local earthquakes

    Science.gov (United States)

    Schneider, John F.; Sacks, I. Selwyn

    1987-12-01

    We study earthquake focal mechanisms in a region of highly contorted subducting lithosphere to identify dominant sources of stress in the subduction process. We observe a stress pattern in the contorted Nazca plate beneath southern Peru from an analysis of hypocentral trend and focal mechanisms of intermediate-depth earthquakes. Expanding on previous studies, we examine the hypocentral trend using 1673 of 2178 well-located local events from the nine-station Arequipa network. The dip of the plate beneath southern Peru averages 25°-30° from 25- to 100-km depth. Below this depth there is an 80- to 100-km-wide contortion between a zone of increasing dip (convex) to the southeast and a flat lying (concave) zone to the northwest. Using more than 6000 P wave first motions of events deeper than 50 km, we derive stress orientations from a moving average of composite focal mechanisms across a 200 by 350 km region including the contortion. The in-plate distribution of tension (T) and compression (P) axes reveals a coherent stress pattern. The trend is most clear beneath south-central Peru (NW section) and below 100- km depth in southernmost Peru (SE section). Both T and P axes tend to be dominantly in plate, especially below 100-km depth. T axes orient toward the contortion in a fan-shaped trend, which suggests that the deepest part of the seismic zone, within the convex SE section, is sinking and pulling the more buoyant NW section. We conclude that from 50- to 200-km depth, slab-pull forces are dominant in the observed stress. Our results suggest that a significant amount of plate extension occurs in this region of intermediate-depth subduction.

  6. Large slope instabilities in Northern Chile and Southern Peru

    Science.gov (United States)

    Crosta, Giovanni B.; Hermanns, Reginald L.; Valbuzzi, Elena; Frattini, Paolo; Valagussa, Andrea

    2014-05-01

    Deep canyon incision into Tertiary paleosurfaces and large slope instabilities along the canyon flanks characterize the landscape of western slope of the Andes of northern Chile and South Peru. This area belongs to the Coastal Escarpment and Precordillera and is formed by coarse-grained clastic and volcanoclastic formations. The area is characterized by intense seismicity and long-term hyperaridity (Atacama Desert). Landslides along the canyon flanks affect volumes generally up to 1 km3 and locally evolved in large rock avalanches. We prepared a landslide inventory covering an area of about 30,000 km2, extending from Iquique (Chile) to the South and Tacna (Peru) to the North. A total of 606 landslides have been mapped in the area by use of satellite images and direct field surveys, prevalently including large phenomena. The landslides range from 1 10-3 km2 to 464 km2 (Lluta landslide). The total landslide area, inclusive of the landslide scarp and of the deposit, amounts to about 2,130 km2 (about 7% of the area). The mega landslides can be classified as large block slides that can evolve in large rock avalanches (e.g. Minimini landslide). Their initiation seems to be strongly associated to the presence of secondary faults and large fractures transversal to the slope. These landslides show evidence suggesting a re-incision by the main canyon network. This seems particularly true for the Lluta collapse where the main 'landslide' mass is masked or deleted by the successive erosion. Other landslides have been mapped along the Coastal Escarpment and some of the major tectonic escarpments with an E-W trend. We examined area-frequency distributions of landslides by developing logarithmically binned, non-cumulative size frequency distributions that report frequency density as a function of landslide planar area A. The size frequency distribution presents a strong undersampling for smaller landslides, due to the extremely old age of the inventory. For landslides larger than

  7. Isolation of viruses from mosquitoes (Diptera: Culicidae) collected in the Amazon Basin region of Peru.

    Science.gov (United States)

    Turell, M J; O'Guinn, M L; Jones, J W; Sardelis, M R; Dohm, D J; Watts, D M; Fernandez, R; Travassos da Rosa, A; Guzman, H; Tesh, R; Rossi, C A; Ludwig, V; Mangiafico, J A; Kondig, J; Wasieloski, L P; Pecor, J; Zyzak, M; Schoeler, G; Mores, C N; Calampa, C; Lee, J S; Klein, T A

    2005-09-01

    As part of a comprehensive study on the ecology of arthropod-borne viruses in the Amazon Basin region of Peru, we assayed 539,694 mosquitoes captured in Loreto Department, Peru, for arboviruses. Mosquitoes were captured either by dry ice-baited miniature light traps or with aspirators while mosquitoes were landing on human collectors, identified to species, and later tested on Vero cells for virus. In total, 164 virus isolations were made and included members of the Alphavirus (eastern equine encephalomyelitis, Trocara, Una, Venezuelan equine encephalomyelitis, and western equine encephalomyelitis viruses), Flavivirus (Ilheus and St. Louis encephalitis), and Orthobunyavirus (Caraparu, Itaqui, Mirim, Murutucu, and Wyeomyia viruses) genera. In addition, several viruses distinct from the above-mentioned genera were identified to the serogroup level. Eastern equine encephalomyelitis virus was associated primarily with Culex pedroi Sirivanakarn & Belkin, whereas Venezuelan equine encephalomyelitis virus was associated primarily with Culex gnomatos Sallum, Huchings & Ferreira. Most isolations of Ilheus virus were made from Psorophora ferox (Von Humboldt). Although species of the Culex subgenus Melanoconion accounted for only 45% of the mosquitoes collected, 85% of the virus isolations were made from this subgenus. Knowledge of the viruses that are being transmitted in the Amazon Basin region of Peru will enable the development of more effective diagnostic assays, more efficient and rapid diagnoses of clinical illnesses caused by these pathogens, risk analysis for military/civilian operations, and development of potential disease control measures.

  8. Floristic diversity of the upper river basin Tambo-Ichuña (Moquegua, Peru

    Directory of Open Access Journals (Sweden)

    Daniel B. Montesinos-Tubée

    2011-06-01

    Full Text Available A study of the floristic diversity of vascular plants is presented from the basin of the Tambo-Ichuña River, the high Andean Puna plateau and wetlands of Ichuña, Ubinas and Yunga Districts (3400 - 4700 m altitude, General Sanchez Cerro Province, Department of Moquegua, Peru. Vascular flora is composed of 70 families, 238 genera and 404 species. The Magnoliopsida represent 78% of the species, Liliopsida 16%, Gymnosperms 0.5% and Pteridophytes 6%. Among lifeforms, the Hemicryptophytes are the most numerous. Three vegetation formations have been identified, the humid scrubland being the most diverse in species richness. Between endemic species, 42 taxa are exclusive to Peru. A total number of 272 new additions of vascular species to the flora of the department of Moquegua are presented.

  9. Internal vein texture and vein evolution of the epithermal Shila-Paula district, southern Peru.

    OpenAIRE

    Chauvet, Alain; Bailly, Laurent; André-Mayer, Anne-Sylvie; Monié, Patrick; Cassard, Daniel; Llosa Tajada, Fernando; Rosas Vargas, Juan; Tuduri, Johann

    2006-01-01

    The epithermal Shila-Paula Au–Ag district is characterized by numerous veins hosted in Tertiary volcanic rocks of the Western Cordillera (southern Peru). Field studies of the ore bodies reveal a systematic association of a main E–W vein with secondary N55–60°W veins—two directions that are also reflected by the orientation of fluid-inclusion planes in quartz crystals of the host rock. In areas where this pattern is not recognized, such as the Apacheta sector, vein emplacement seems to have be...

  10. Geodetic, teleseismic, and strong motion constraints on slip from recent southern Peru subduction zone earthquakes

    OpenAIRE

    Pritchard, M. E.; Norabuena, E. O.; Jillings, C.; Boroschek, R.; Comte, D.; Simons, M.; T. H. Dixon; Rosen, P. A.

    2007-01-01

    We use seismic and geodetic data both jointly and separately to constrain coseismic slip from the 12 November 1996 M_w 7.7 and 23 June 2001 M_w 8.5 southern Peru subduction zone earthquakes, as well as two large aftershocks following the 2001 earthquake on 26 June and 7 July 2001. We use all available data in our inversions: GPS, interferometric synthetic aperture radar (InSAR) from the ERS-1, ERS-2, JERS, and RADARSAT-1 satellites, and seismic data from teleseismic and strong motion stations...

  11. Alboran Basin, southern Spain - Part I: Geomorphology

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, A. [Secretaria General de Pesca Maritima, Corazon de Maria, 8, 28002 Madrid (Spain); Ballesteros, M.; Rivera, J.; Acosta, J. [Instituto Espanol de Oceanografia, Corazon de Maria, 8, 28002 Madrid (Spain); Montoya, I. [Universidad Juan Carlos I, Campus de Mostoles, Madrid (Spain); Uchupi, E. [Woods Hole Oceanographic Institution, Woods Hole, MA 02543 (United States)

    2008-01-15

    Bathymetric, 3D relief and shaded relief maps created from multibeam echo-sounding data image the morphology of the Alboran Basin, a structural low along the east-west-trending Eurasian-African plates boundary. Topographic features in the basin are the consequence of volcanism associated with Miocene rifting, rift and post-rift sedimentation, and recent faulting resulting from the convergence of the African-Eurasian plates. Pleistiocene glacially induced regressions/transgressions when the sea level dropped to about 150 m below its present level gas seeps and bottom currents. Recent faulting and the Pleistocene transgressions/regressions led to mass-wasting, formation of turbidity currents and canyon erosion on the basin's slopes. Recent fault traces at the base of the northern basin slope have also served as passageways for thermogenic methane, the oxidation of which by bacteria led to the formation of carbonate mounds along the fault intercepts on the sea floor. Expulsion of thermogenic or biogenic gas has led to the formation of pockmarks; erosion by bottom currents has resulted in the formation of moats around seamounts and erosion of the seafloor of the Alboran Ridge and kept the southern edge of the 36 10'N high sediment free. (author)

  12. Variability in New Shortening Estimates from Southern Peru (12-14S); Implications for Mass Balance of the Andean Plateau.

    Science.gov (United States)

    Gotberg, N.; McQuarrie, N.

    2008-12-01

    One of the fundamental questions of interest with regards to the Andean Plateau is the mass balance of material needed to create and sustain a 3-4 km high plateau. Is crustal shortening sufficient to support an isostatically compensated crust of 60-70km? We present new estimates of shortening across the northern margin of the Andean Plateau. The cross section extent, from the eastern edge of the volcanic arc to foreland basin, is approximately one half of the physiographic width of the Andean Plateau in Peru. Cross sectional shortening estimates in southern Peru (12-14°S) provide a best estimate of 123 km or 40% shortening with an absolute minimum estimate of 86 km or 30% and absolute maximum estimate of 275 km or 60%. We determined the maximum and minimum shortening estimates using the cross sectional area and possible variations in assumptions made about the amount of erosion, detachment dip, involvement of basement thrusts and displacement along faults. The best estimate of shortening is well short of the required 240-300km of shortening needed in order to account for a 60-70km thick crust under the entire plateau. This suggests that for an isostatically equilibrated crust either 1) there is a significant amount of shortening (~150km) in the western half of the plateau which, is hidden by the volcanic arc or 2) crustal material is being added to the Peruvian section of the Andean Plateau either through lower crustal flow or a process of magmatic underplating followed by differentiation and delamination.

  13. Molecular taxonomy of Anopheles (Nyssorhynchus) benarrochi (Diptera: Culicidae) and malaria epidemiology in southern Amazonian Peru.

    Science.gov (United States)

    Conn, Jan E; Moreno, Marta; Saavedra, Marlon; Bickersmith, Sara A; Knoll, Elisabeth; Fernandez, Roberto; Vera, Hubert; Burrus, Roxanne G; Lescano, Andres G; Sanchez, Juan Francisco; Rivera, Esteban; Vinetz, Joseph M

    2013-02-01

    Anopheline specimens were collected in 2011 by human landing catch, Shannon and CDC traps from the malaria endemic localities of Santa Rosa and San Pedro in Madre de Dios Department, Peru. Most specimens were either Anopheles (Nyssorhynchus) benarrochi B or An. (Nys.) rangeli, confirmed by polymerase chain reaction-restriction fragment length polymorphism-internal transcribed spacer 2 (PCR-RFLP-ITS2) and, for selected individuals, ITS2 sequences. A few specimens from Lupuna, Loreto Department, northern Amazonian Peru, were also identified as An. benarrochi B. A statistical parsimony network using ITS2 sequences confirmed that all Peruvian An. benarrochi B analyzed were identical to those in GenBank from Putumayo, southern Colombia. Sequences of the mtDNA COI BOLD region of specimens from all three Peruvian localities were connected using a statistical parsimony network, although there were multiple mutation steps between northern and southern Peruvian sequences. A Bayesian inference of concatenated Peruvian sequences of ITS2 + COI detected a single clade with very high support for all An. benarrochi B except one individual from Lupuna that was excluded. No samples were positive for Plasmodium by CytB-PCR.

  14. Tectonic and climatic controls on the Chuquibamba landslide (western Andes, southern Peru)

    Science.gov (United States)

    Margirier, A.; Audin, L.; Carcaillet, J.; Schwartz, S.; Benavente, C.

    2015-06-01

    The contribution of landslides to the Quaternary evolution of relief is poorly documented in arid contexts. In southern Peru and northern Chile, several massive landslides disrupt the arid western Andean front. The Chuquibamba landslide, located in southern Peru, belongs to this set of large landslides. In this area, the Incapuquio fault system captures the intermittent drainage network and localizes rotational landslides. Seismic activity is significant in this region with recurrent Mw 9 subduction earthquakes; however, none of the latest seismic events have triggered a major landslide. New terrestrial cosmogenic dating of the Chuquibamba landslide provides evidence that the last major gravitational mobilization of these rotational landslide deposits occurred at ~ 102 ka, during the Ouki wet climatic event identified on the Altiplano between 120 and 98 ka. Our results suggest that wet events in the arid and fractured context of the Andean forearc induced these giant debris flows. Finally, our study highlights the role of tectonics and climate on (i) the localization of large Andean landslides in the Western Cordillera and on (ii) the long-term mass transfer to the trench along the arid Andean front.

  15. Seismic structure along transitions from flat to normal subduction: central Mexico, southern Peru, and southwest Japan

    Science.gov (United States)

    Dougherty, Sara L.

    The fine-scale seismic structure of the central Mexico, southern Peru, and southwest Japan subduction zones is studied using intraslab earthquakes recorded by temporary and permanent regional seismic arrays. The morphology of the transition from flat to normal subduction is explored in central Mexico and southern Peru, while in southwest Japan the spatial coincidence of a thin ultra-slow velocity layer (USL) atop the flat slab with locations of slow slip events (SSEs) is explored. This USL is also observed in central Mexico and southern Peru, where its lateral extent is used as one constraint on the nature of the flat-to-normal transitions. In western central Mexico, I find an edge to this USL which is coincident with the western boundary of the projected Orozco Fracture Zone (OFZ) region. Forward modeling of the 2D structure of the subducted Cocos plate using a finite-difference algorithm provides constraints on the velocity and geometry of the slab's seismic structure in this region and confirms the location of the USL edge. I propose that the Cocos slab is currently fragmenting into a North Cocos plate and a South Cocos plate along the projection of the OFZ, by a process analogous to that which occurred when the Rivera plate separated from the proto-Cocos plate 10 Ma. In eastern central Mexico, observations of a sharp transition in slab dip near the abrupt end of the Trans Mexican Volcanic Belt (TMVB) suggest a possible slab tear located within the subducted South Cocos plate. The eastern lateral extent of the USL is found to be coincident with these features and with the western boundary of a zone of decreased seismicity, indicating a change in structure which I interpret as evidence of a possible tear. Analysis of intraslab seismicity patterns and focal mechanism orientations and faulting types provides further support for a possible tear in the South Cocos slab. This potential tear, together with the tear along the projection of the OFZ to the northwest

  16. Exploration Breakthrough in Southern Margin of Junggar Basin

    Institute of Scientific and Technical Information of China (English)

    Kang Zhulin; Zheng Jiandong

    1997-01-01

    @@ The Hutubi structure, located in the southern margin of Junggar Basin, is 60 km norrthwest of Urumqi and 20 km northwest of Changji (Fig. l). The Hu-2 well drilled in the Hutubi structure has gained high-yield gas flow,significant exploration breakthrough in the southern margin of Junggar Basin since the 1950s.

  17. Tectonic geomorphology of large normal faults bounding the Cuzco rift basin within the southern Peruvian Andes

    Science.gov (United States)

    Byers, C.; Mann, P.

    2015-12-01

    The Cuzco basin forms a 80-wide, relatively flat valley within the High Andes of southern Peru. This larger basin includes the regional capital of Cuzco and the Urubamba Valley, or "Sacred Valley of the Incas" favored by the Incas for its mild climate and broader expanses of less rugged and arable land. The valley is bounded on its northern edge by a 100-km-long and 10-km-wide zone of down-to-the-south systems of normal faults that separate the lower area of the down-dropped plateau of central Peru and the more elevated area of the Eastern Cordillera foldbelt that overthrusts the Amazon lowlands to the east. Previous workers have shown that the normal faults are dipslip with up to 600 m of measured displacements, reflect north-south extension, and have Holocene displacments with some linked to destructive, historical earthquakes. We have constructed topographic and structural cross sections across the entire area to demonstrate the normal fault on a the plateau peneplain. The footwall of the Eastern Cordillera, capped by snowcapped peaks in excess of 6 km, tilts a peneplain surface northward while the hanging wall of the Cuzco basin is radially arched. Erosion is accelerated along the trend of the normal fault zone. As the normal fault zone changes its strike from east-west to more more northwest-southeast, normal displacement decreases and is replaced by a left-lateral strike-slip component.

  18. An endemic new species of Ameiva (Squamata: Teiidae) from an isolated dry   forest in southern Peru.

    Science.gov (United States)

    Landauro, Caroll Z; García-Bravo, Antonio; Venegas, Pablo J

    2015-01-01

    We describe a new species of Ameiva from an interandean dry forest in central-southern Peru. Ameiva reticulata sp. nov. represents the fifth species in the genus known to occur in Peru. The new species is similar to the species of the A. ameiva complex such as A. ameiva, A. atrigularis, A. pantherina, and A. praesignis, and is distinguished from these by a smaller size, a lower count of dorsal scales along the middorsal line and scales across the midbody, and by the gular coloration. PMID:25947699

  19. Imaging Lithospheric-scale Structure Beneath Northern Altiplano in Southern Peru and Northern Bolivia

    Science.gov (United States)

    Kumar, A.; Wagner, L. S.; Beck, S. L.; Zandt, G.; Long, M. D.

    2014-12-01

    The northern Altiplano plateau of southern Peru and northern Bolivia is one of the highest topographic features on the Earth, flanked by Western and Eastern Cordillera along its margin. It has strongly influenced the local and far field lithospheric deformation since the early Miocene (Masek et al., 1994). Previous studies have emphasized the importance of both the crust and upper mantle in the evolution of Altiplano plateau (McQuarrie et al., 2005). Early tomographic and receiver function studies, south of 16° S, show significant variations in the crust and upper mantle properties in both perpendicular and along strike direction of the Altiplano plateau (Dorbath et. al., 1993; Myers et al., 1998; Beck and Zandt, 2002). In order to investigate the nature of subsurface lithospheric structure below the northern Altiplano, between 15-18° S, we have determined three-dimensional seismic tomography models for Vp and Vs using P and S-wave travel time data from two recently deployed local seismic networks of CAUGHT and PULSE. We also used data from 8 stations from the PERUSE network (PERU Subduction Experiment). Our preliminary tomographic models show a complex variation in the upper mantle velocity structure with depth, northwest and southeast of lake Titicaca. We see the following trend, at ~85 km depth, northwest of lake Titicaca: low Vp and Vs beneath the Western Cordillera, high Vs beneath the Altiplano and low Vp and Vs beneath the Eastern Cordillera. This low velocity anomaly, beneath Eastern Cordillera, seems to coincide with Kimsachata, a Holocene volcano in southern Peru. At depth greater than ~85 km: we find high velocity anomaly beneath the Western Cordillera and low Vs beneath the Altiplano. This high velocity anomaly, beneath Western Cordillera, coincides with the well-located Wadati-Benioff zone seismicity and perhaps represents the subducting Nazca slab. On the southeast of lake Titicaca, in northern Bolivia, we see a consistently high velocity anomaly

  20. Determination of Nazca slab geometry and state of stress beneath the southern Peru and northern Bolivia

    Science.gov (United States)

    Kumar, A.; Wagner, L. S.; Beck, S. L.; Young, B. E.; Zandt, G.; Long, M. D.; Tavera, H.; Minaya, E.

    2013-12-01

    Subduction of the Nazca plate in the north central Andes beneath southern Peru and northern Bolivia is of prime importance because of the role it plays in the evolution of topographic features since the late Eocene (~40 Ma). Previous studies based on slab event locations constrained only with teleseismic data defined a broad area of flat slab subduction in central and southern Peru, which transitions to a normally dipping slab beneath the northernmost Altiplano Plateau. We present earthquake locations and focal mechanisms using data from two temporary arrays: the network of 50 broadband seismic stations that were part of the NSF-Continental Dynamics-funded project 'CAUGHT' (Central Andean Uplift and the Geodynamics of High Topography) and the 40 station NSF- Geophysics funded 'PULSE' array (PerU Lithosphere and Slab Experiment). Our earthquake locations provide new information about the geometry of subducting Nazca slab between 13°S to 18°S. A significant clustering of intermediate depth earthquakes at ~15.5°S and 18°S suggests strong and localized release of tectonic stress in the slab perhaps due to bending and unbending. There are not enough intra-slab events at depth greater than 100 km to constrain the flat slab width north of 14°S. Our analyses indicate that the flat slab is at least 10 to 12 km shallower than the previous estimates (e.g. Cahill and Isacks, 1992; Ramos, 2009). Focal mechanisms and stress axis orientation of slab events at ~15.5°S indicate down-dip extension, where the dip changes from subhorizontal to steeply dipping slab. The continuity in the trend of stress suggests that the slab is deformed but not torn where it transitions from flat to steeply dipping. Data from local slab events will eventually be incorporated into a local tomographic body wave inversion to better constrain the velocity structure of the mantle lithosphere and asthenosphere below the Altiplano. This in turn will provide the valuable information on the process

  1. Genetic diversity of vaccine candidate antigens in Plasmodium falciparum isolates from the Amazon basin of Peru

    Directory of Open Access Journals (Sweden)

    Lucas Carmen M

    2008-05-01

    Full Text Available Abstract Background Several of the intended Plasmodium falciparum vaccine candidate antigens are highly polymorphic and could render a vaccine ineffective if their antigenic sites were not represented in the vaccine. In this study, characterization of genetic variability was performed in major B and T-cell epitopes within vaccine candidate antigens in isolates of P. falciparum from Peru. Methods DNA sequencing analysis was completed on 139 isolates of P. falciparum collected from endemic areas of the Amazon basin in Loreto, Peru from years 1998 to 2006. Genetic diversity was determined in immunological important regions in circumsporozoite protein (CSP, merozoite surface protein-1 (MSP-1, apical membrane antigen-1 (AMA-1, liver stage antigen-1 (LSA-1 and thrombospondin-related anonymous protein (TRAP. Alleles identified by DNA sequencing were aligned with the vaccine strain 3D7 and DNA polymorphism analysis and FST study-year pairwise comparisons were done using the DnaSP software. Multilocus analysis (MLA was performed and average of expected heterozygosity was calculated for each loci and haplotype over time. Results Three different alleles for CSP, seven for MSP-1 Block 2, one for MSP-1 Block 17, three for AMA-1 and for LSA-1 each and one for TRAP were identified. There were 24 different haplotypes in 125 infections with complete locus typing for each gene. Conclusion Characterization of the genetic diversity in Plasmodium isolates from the Amazon Region of Peru showed that P. falciparum T and B cell epitopes in these antigens have polymorphisms more similar to India than to Africa. These findings are helpful in the formulation of a vaccine considering restricted repertoire populations.

  2. Chromium isotope composition of reducing and anoxic sediments from the Peru Margin and Cariaco Basin

    Science.gov (United States)

    Gueguen, B.; Planavsky, N.; Wang, X.; Algeo, T. J.; Peterson, L. C.; Reinhard, C. T.

    2014-12-01

    Chromium isotope systematics in marine sediments are now being used as a new redox proxy of the modern and ancient Earth's surface. Chromium is primarily delivered to the oceans by riverine inputs through weathering of Cr(III)-rich minerals present in the continental crust and oxidation of insoluble Cr(III) to soluble Cr(VI) species. Since oxidation-reduction reactions fractionate Cr isotopes whereby oxidized Cr(VI) species are preferentially enriched in heavy Cr isotopes, the Cr isotope composition of marine sediments may be useful tracers of redox conditions at the Earth's surface through geological time. Chromium is quantitatively removed in organic-rich sediments where reducing conditions prevail and promote reduction of Cr(VI) to Cr(III), and thus, these sediments should capture the ambient seawater Cr isotope composition. However, the isotopic composition of modern organic-rich sediments is poorly documented so far, and this step is essential for further modeling the global oceanic Cr isotope mass balance and assessing the effects of sedimentation and post-depositional processes on the marine Cr isotopes archive. In this study, we have characterized modern marine organic-rich sediments for their Cr isotope composition (δ53/52Cr) from two different settings, the Peru margin upwelling zone and the anoxic Cariaco Basin (Venezuela). Chromium isotopes were measured on a MC-ICP-MS (Nu Plasma) using a double-spike correction method. The authigenic fraction of shallow samples from the Peru margin sedimentary sequence with a high Total Organic Carbon (TOC) content (>10 wt%) yield an average δ53/52Crauthigenic value of +0.67 ±0.05 ‰ (2sd). However, although this value is close to the seawater value (Atlantic Ocean) and to Cariaco basin sediments (~ +0.6 ‰), reducing sediments from the Peru margin are on average isotopically slightly heavier, especially in samples having a low authigenic fraction and a low TOC content (δ53/52Crauthigenic values up to +1.30

  3. Olivine in the Southern Isidis Basin

    Science.gov (United States)

    2007-01-01

    The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) took this observation of the transition region between Libya Montes and the Isidis Basin on Mars at 17:16 UTC (12:16 p.m. EST) on January 2, 2007, near 3.6 degrees north latitude, 84.1 degrees east longitude. The image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 18 meters (60 feet) across. The image is about 11 kilometers (7 miles) wide at its narrowest point. The Isidis Basin resulted from of a gigantic impact on the surface of Mars early in the planet's history. The southern rim, where this target is located, is a region of complex geology and part of the planetary dichotomy boundary that separates the older southern highlands from the lower, younger northern plains. The image on the left was constructed from three visible wavelengths (RGB: 0.71, 0.60, 0.53 microns) and is a close approximation of how the surface would appear to the human eye. The image on the right was constructed from three infrared wavelengths (RGB: 2.49, 1.52, 1.08 microns) chosen to highlight variations in the mineralogy of the area. Of interest is that features in this image not only differ in color, but also in texture and morphology. The gray areas absorb similarly at all wavelengths used in this image, but display absorptions at other wavelengths related to the iron- and magesium-rich mineral pyroxene. The reddest areas absorb strongly at the wavelengths used for green and blue, which is attributable to another iron- and magesium-rich mineral, olivine. The brownish areas show subdued mineral absorptions and could represent some type of mixture between the other two materials. The presence of the mineral olivine is particularly interesting because olivine easily weathers to other minerals; thus, its presence indicates either the lack of weathering in this region or relatively recent exposure. CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and

  4. Pollution by heavy metals in the Moche River Basin, 1980 - 2010, La Libertad - Peru

    Directory of Open Access Journals (Sweden)

    Félix Huaranga Moreno

    2012-09-01

    Full Text Available The pollution of the continental waters is a problem at a world scale, mainly due to the impact of the mining tailings. Using top technologies as neutralization plants of acid waters, many companies are mitigating the impact of this functioning; so taking as a reference the changes in the concentration of heavy metals present in water, soils and cultivations of the high, middle and low basin of the Moche river, samplings of water were obtained at eight stations of the Moche river (Trujillo, Peru, and in four sectors of its margins for soils and cultivations. The most representative heavy metals in water were found in the high basin during the year 1980: iron (557.500 ppm, lead (100.375 ppm, cadmium (4.550 ppm, copper (6.900 ppm, zinc (262.900 ppm and arsenic (9.000 ppm; whereas in the soils the higher concentrations were found on the right margin of median basin in the year 1980: iron (83.400 mg/kg; lead (0.820 mg/kg; cadmium (0.012 mg/kg; copper (1.240 mg/kg; zinc (0.380 mg/kg and arsenic (0.016 mg/kg; in relation to the metal accumulation in the cultivations, iron (0.6525 mg/kg was predominant, being the yucca (Manihot esculentus the most contaminated cultivation. It is concluded that, most contamination level of water analysis was present in the high basin during 1980, whereas the right side of the median basin highest levels of contamination in the samples of soils; relating to the cultives, the yucca (Manihot esculentus was the species most contaminated.

  5. 3D Body Wave Velocity Tomography in Southern Peru: Seismotectonic Implications

    Science.gov (United States)

    Gallego, A.; Perez, J.; David, C.; Comte, D.; Charrier, R.; Dorbath, L.

    2004-12-01

    The studied region corresponds to the southern segment of the 1868 rupture area, that did not break with the last Mw=8.4 Arequipa earthquake in southern Peru. A temporary network of 19 short period, continuous recording seismic stations was deployed (16.5° -18.5° S; 69.5° -72° W) between December 2002-March 2003 in this region. The 1093 select events were used for a joint hypocentral and velocity structure inversion. The first obtained 1D velocity model was used as the initial model for the 3D inversion, consisting in 231 blocks distributed along layers separated by 10 km for depths lower than 80 km, and by 20 km for depths between 80 and 160 km. North of the Arica Bend, between the Coast and Andean Range the high Vp velocity and Vp/Vs ratio observed at depths lower than 10 km could represent the Precambrian basement uplifted by the Incapuquio sinistral fault system, which develops a positive flower structure typical for transpressional zones, that raised the basement. This behavior is in good agreement with the uplift of the Cambrian metamorphic complex, in the Precordillera south of the Arica Bend (northern Chile), by the west-vergent thrust system. Beneath the anomalous high velocities (between 20 and 30 km depth), a low velocity zone (Vpearthquake post-seismic period.

  6. Seismicity and structure of Nazca Plate subduction zone in southern Peru

    Science.gov (United States)

    Lim, H.; Kim, Y.; Clayton, R. W.

    2015-12-01

    We image the Nazca plate subduction zone system by detecting and (re)locating intra-slab earthquakes in southern Peru. Dense seismic arrays (PeruSE, 2013) were deployed along four lines to target geophysical characterization of the subduction system in the transition zone between flat and normal dipping segments of the Nazca plate (2-15°S). The arc volcanism is absent near the flat slab segment, and currently, the correlation between the location of the active volcanic front and corresponding slab depth is neither clear nor consistent between previously published models from seismicity. We detect 620 local earthquakes from August 2008 to February 2013 by manually picking 6559 and 4145 arrival times for P- and S-phases, respectively. We observe that the S-phase data is helpful to reduce the trade-off between origin time and depth of deeper earthquakes (>100 km). Earthquake locations are relocated to constrain the Nazca slab-mantle interface in the slab-dip transition zone using 7322 measurements of differential times of nearby earthquake pairs by waveform cross-correlation. We also employ the double-difference tomography (Zhang and Thurber, 2003) to further improve earthquake source locations and the spatial resolution of the velocity structure simultaneously. The relocated hypocenters clearly delineate the dipping Wadati-Benioff zone in the slab-dip transition zone between the shallow- (25°) to-flat dipping slab segment in the north and the normal (40°) dipping segment in the south. The intermediate-depth seismicity in the flat slab region stops at a depth of ~100 km and a horizontal distance of ~400 km from the trench. We find a significant slab-dip difference (up to 10°) between our relocated seismicity and previously published slab models along the profile region sampling the normal-dip slab at depth (>100 km).

  7. Structural inheritance and selective reactivation in the central Andes: Cenozoic deformation guided by pre-Andean structures in southern Peru

    Science.gov (United States)

    Perez, Nicholas D.; Horton, Brian K.; Carlotto, Victor

    2016-03-01

    Structural, stratigraphic, and geochronologic constraints from the Eastern Cordillera in the central Andean plateau of southern Peru (14-15°S) demonstrate the existence and position of major pre-Andean structures that controlled the accumulation of Triassic synrift fill and guided subsequent Cenozoic deformation. The timing of initial clastic deposition of the Triassic Mitu Group is here constrained to ~ 242-233 Ma on the basis of detrital and volcanic zircon U-Pb geochronology. Regionally distinct provenance variations, as provided by U-Pb age populations from localized synrift accumulations, demonstrate Triassic erosion of multiple diagnostic sources from diverse rift-flank uplifts. Stratigraphic correlations suggest synchronous initiation of extensional basins containing the Mitu Group, in contrast with previous interpretations of southward rift propagation. Triassic motion along the NE-dipping San Anton normal fault accommodated up to 7 km of throw and hanging-wall deposition of a synrift Mitu succession > 2.5 km thick. The contrasting orientation of a non-reactivated Triassic normal fault suggests selective inversion of individual structures in the Eastern Cordillera was dependent on fault dip and strike. Selective preservation of a ~ 4 km thick succession of Carboniferous-Permian strata in the down-dropped San Anton hanging wall, beneath the synrift Mitu Group, suggests large-scale erosional removal in the uplifted footwall. Field and map observations identify additional pre-Andean thrust faults and folds attributed to poorly understood Paleozoic orogenic events preserved in the San Anton hanging wall. Selective thrust reactivation of normal and reverse faults during later compression largely guided Cenozoic deformation in the Eastern Cordillera. The resulting structural compartmentalization and across-strike variations in kinematics and deformation style highlight the influence of inherited Paleozoic structures and Triassic normal faults on the long

  8. Chrysobrycon yoliae, a new species of stevardiin (Characiformes: Characidae from the Ucayali basin, Peru

    Directory of Open Access Journals (Sweden)

    James Anyelo Vanegas-Ríos

    2014-06-01

    Full Text Available Chrysobrycon yoliae, new species, is described from a drainage flowing into the río Yucamia basin, río Ucayali basin, Peru. Chrysobrycon yoliaeis readily distinguished from its congeners by the anterior tip of pelvic bone situated anterior to the fifth rib (vs. situated posterior to the fifth rib, the presence of 20-26 dentary teeth (vs. 11-19, and the possession of a terminal lateral-line tube between caudal-fin rays 10 and 11 (vs. the absence of this tube, except in C. eliasi. The new species differs from C. eliasiand C. myersiby the presence of teeth on third pharyngobranchial (vs. the absence of teeth on this bone and also differs from C. eliasiby the dorsal-fin origin situated at vertical through anal-fin rays 5 to 7 (vs. located at vertical through anal-fin rays 8 to 10, the posterior extent of the ventral process of quadrate reaching the vertical through posterior margin of symplectic (vs. not reaching the vertical through posterior margin of symplectic, the dorsal-fin to adipose-fin length 26.8-28.8% SL (vs. 23.9-26.8% SL, and the body depth at dorsal-fin origin 34.4-42.2% SL (vs. 24.1-34.5% SL. A key for the identification of Chrysobryconspecies is provided.

  9. Geodetic, teleseismic, and strong motion constraints on slip from recent southern Peru subduction zone earthquakes

    Science.gov (United States)

    Pritchard, M. E.; Norabuena, E. O.; Ji, C.; Boroschek, R.; Comte, D.; Simons, M.; Dixon, T. H.; Rosen, P. A.

    2007-03-01

    We use seismic and geodetic data both jointly and separately to constrain coseismic slip from the 12 November 1996 Mw 7.7 and 23 June 2001 Mw 8.5 southern Peru subduction zone earthquakes, as well as two large aftershocks following the 2001 earthquake on 26 June and 7 July 2001. We use all available data in our inversions: GPS, interferometric synthetic aperture radar (InSAR) from the ERS-1, ERS-2, JERS, and RADARSAT-1 satellites, and seismic data from teleseismic and strong motion stations. Our two-dimensional slip models derived from only teleseismic body waves from South American subduction zone earthquakes with Mw > 7.5 do not reliably predict available geodetic data. In particular, we find significant differences in the distribution of slip for the 2001 earthquake from models that use only seismic (teleseismic and two strong motion stations) or geodetic (InSAR and GPS) data. The differences might be related to postseismic deformation or, more likely, the different sensitivities of the teleseismic and geodetic data to coseismic rupture properties. The earthquakes studied here follow the pattern of earthquake directivity along the coast of western South America, north of 5°S, earthquakes rupture to the north; south of about 12°S, directivity is southerly; and in between, earthquakes are bilateral. The predicted deformation at the Arequipa GPS station from the seismic-only slip model for the 7 July 2001 aftershock is not consistent with significant preseismic motion.

  10. Integrating short-term and long-term forecasting with reservoir optimisation; Mantaro Basin, Peru.

    Science.gov (United States)

    Jensen, R. A.; Lasarte, A.; Butts, M. B.

    2009-04-01

    Operational water management often requires a trade-off between short-term and long-term water demands, where short-term demands are driven for example by hydropower generation and flood protection requirements and the long-term demands by water and irrigation supply, sustainable reservoir management and the seasonal impacts of snow melt or climate. This paper presents an operational decision support system designed to forecast and optimise reservoir operations in both the short-term and long-term. The system has been established for the 20,000 km2 Mantaro river basin located in the high Andes with altitudes ranging from 3500 to nearly 6000 m.a.s.l.. The two main power stations at Tablachaca have a combined capacity of more than 1000 MW that supplies 30% of Peru's electrical energy. In addition, the basin's water resources supply extensive agricultural areas, an urban population and mining activities and sustain important ecological habitats. In this paper, the methodologies used for the integrating short-term and long-term forecasting are presented together with their application to the optimal operation of reservoirs. A key element in the system is the MIKE BASIN modelling tool. The system uses several modelling capabilities of MIKE BASIN: rainfall-runoff, reservoir operation, hydropower production, and river flow routing. The system also takes advantage of long-term forecasts (based on statistical information) and short-term forecasts (based on telemetry data). The continually updated runoff and flow forecasts enter the optimization, which applies the Model Predictive Control principle for MIKE BASIN as the core simulation model. For each optimization, a non-linear program algorithm is used to find the best release strategy. On the basis of the forecasted inflows and the real time data the system suggests to the user from which reservoirs to release water for alleviation of possible forecasted deficits. In addition to the Tablachaca scheme the model accounts for

  11. Taxonomy and new collections of wild potato species in Central and Southern Peru in 1999

    NARCIS (Netherlands)

    Salas, A.R.; Spooner, D.M.; Huamán, Z.; Torres Maita, R.V.; Hoekstra, R.; Schüler, K.; Hijmans, R.J.

    2001-01-01

    Peru contains about half of the described wild potato taxa, and many of these are not yet preserved in genebanks. This paper reports results of the second of a series of five planned collecting expeditions to Peru. Collections were made in the central Peruvian departments of Ancash, Huancavelica, La

  12. Alluvial plain dynamics in the southern Amazonian foreland basin

    OpenAIRE

    Lombardo, U

    2015-01-01

    Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation ...

  13. Petroleum System Modelling of Onshore Mandawa Basin - Southern, Tanzania

    OpenAIRE

    Maganza, Neema Ernest

    2014-01-01

    The Mandawa Basin is located along the coast in the southern part of Tanzania, and is potentially one of the most hydrocarbon prospective in the country, as it believed to contain all the essential petroleum system elements. Hydrocarbon exploration and drilling in the basin has been done since the 1950’s but, in spite of the considerable exploration and drilling activities that have been carried out, no economical discoveries have been made. Gas and oil shows in a few wells significantly...

  14. The eruptive chronology of the Ampato-Sabancaya volcanic complex (Southern Peru)

    Science.gov (United States)

    Samaniego, Pablo; Rivera, Marco; Mariño, Jersy; Guillou, Hervé; Liorzou, Céline; Zerathe, Swann; Delgado, Rosmery; Valderrama, Patricio; Scao, Vincent

    2016-09-01

    We have reconstructed the eruptive chronology of the Ampato-Sabancaya volcanic complex (Southern Peru) on the basis of extensive fieldwork, and a large dataset of geochronological (40K-40Ar, 14C and 3He) and geochemical (major and trace element) data. This volcanic complex is composed of two successive edifices that have experienced discontinuous volcanic activity from Middle Pleistocene to Holocene times. The Ampato compound volcano consists of a basal edifice constructed over at least two cone-building stages dated at 450-400 ka and 230-200 ka. After a period of quiescence, the Ampato Upper edifice was constructed firstly during an effusive stage (80-70 ka), and then by the formation of three successive peaks: the Northern, Southern (40-20 ka) and Central cones (20-10 ka). The Southern peak, which is the biggest, experienced large explosive phases, resulting in deposits such as the Corinta plinian fallout. During the Holocene, eruptive activity migrated to the NE and constructed the mostly effusive Sabancaya edifice. This cone comprised many andesitic and dacitic blocky lava flows and a young terminal cone, mostly composed of pyroclastic material. Most samples from the Ampato-Sabancaya define a broad high-K magmatic trend composed of andesites and dacites with a mineral assemblage of plagioclase, amphibole, biotite, ortho- and clino-pyroxene, and Fe-Ti oxides. A secondary trend also exists, corresponding to rare dacitic explosive eruptions (i.e. Corinta fallout and flow deposits). Both magmatic trends are derived by fractional crystallisation involving an amphibole-rich cumulate with variable amounts of upper crustal assimilation. A marked change in the overall eruptive rate has been identified between Ampato (~ 0.1 km3/ka) and Sabancaya (0.6-1.7 km3/ka). This abrupt change demonstrates that eruptive rates have not been homogeneous throughout the volcano's history. Based on tephrochronologic studies, the Late Holocene Sabancaya activity is characterised by strong

  15. The Southern Region of Peru Earthquake of June 23rd, 2001

    Science.gov (United States)

    Tavera, Hernando; Fernández, Efraín; Bernal, Isabel; Antayhua, Yanet; Agüero, Consuelo; Rodríguez, Henry Salas Simeón; Vilcapoma, Luis; Zamudio, Yolanda; Portugal, David; Inza, Adolfo; Carpio, Julia; Ccallo, Freddy; Valdivia, Igor

    2006-04-01

    The western border of South America is one of the most important seismogenic regions in the world. In this region the most damaging earthquake ever recorded occurred. In June 23rd, 2001, another very strong earthquake (Mw = 8.1-8.2) occurred and produced death and damages in the whole southern region of Peru. This earthquake was originated by a friction process between Nazca and South American plates and affected an area of about 300 km × 120 km defined by the distribution of more than 220 aftershocks recorded by a local seismic network that operated 20 days. The epicenter of the main shock was localized in the northwestern extremity of the aftershock area, which suggests that the rupture propagated towards the SE direction. The modeling of P-wave for teleseismic distances permitted to define a focal mechanism of reverse type with NW-SE oriented nodal planes and a possible fault plane moving beneath almost horizontally in NE direction. The source time function (STF) suggests a complex process of rupture during 85 sec with 2 successive sources. The second one of greater size, and located approximately 100-120 km toward the SE direction was estimated to have a rupture velocity of about 2 km/sec on a 28°-dipping plane to the SE (N135°). A second event happened 45 sec after the first one with an epicenter 130km farther to the SE and a complex STF. This event and the second source of the main shock caused a Tsunami with waves from 7 to 8 meters that propagated almost orthogonally to the coast line, by affecting mainly the Camaná area. Three of all the aftershocks presented magnitudes greater or equal to Mw = 6.6, two of them occurred in front of the cities of Ilo and Mollendo (June 26th and July 7th) with focal mechanisms similar to the main seismic event. The aftershock of July 5th shows a normal mechanism at a depth of 75 km, and is therefore most likely located within the subducting Nazca plate and not in the coupling. The aftershocks of June 26th (Mw = 6.6) and

  16. The Progreso Basin Province of Northwestern Peru and Southwestern Ecuador: Neogene and Cretaceous-Paleogene Total Petroleum Systems

    Science.gov (United States)

    Higley, Debra K.

    2004-01-01

    The Progreso Basin province (6083) in northwestern Peru and southwestern Ecuador consists of the Paleogene Santa Elena block and Peru Bank, and the Neogene Tumbes-Progreso subbasin. The Santa Elena block and Peru Bank are part of the Cretaceous-Paleogene Total Petroleum System (TPS)(608302), which contains the Cretaceous-Paleogene Santa Elena Block Assessment Unit (60830201). The Tumbes- Progreso subbasin includes the Neogene TPS (608301) and associated Neogene Pull-Apart Basin Assessment Unit (60830101). The complex tectonic history of the Progreso Basin province influenced depositional and erosional patterns across the region, and also the location, timing, and types of seals, traps, possible source and reservoir rocks, and hydrocarbon generation and migration. Marine shales that are interbedded with and overlie reservoir intervals are the probable hydrocarbon source rocks. Timing of hydrocarbon generation and migration was probably Miocene and younger, following creation of the Tumbes-Progreso subbasin by movement along the Dolores-Guayaquil megashear. More than 220 million barrels of oil (MMBO) and 255 billion cubic feet of gas (BCFG) have been produced from the Progreso Basin province. The means of estimated recoverable oil, gas, and natural gas liquids (NGL) resources from undiscovered fields in the province are 237 MMBO, 695 BCFG, and 32 MMB NGL, respectively. The means of estimated recoverable oil, gas, and NGL resources from undiscovered onshore fields are 45 MMBO, 113 BCFG, and 5 MMBNGL, and from undiscovered offshore fields are 192 BBO, 582 BCFG, and 27 MMBNGL. These are USGS grown undiscovered resources that were determined by using a minimum field size of 1 million barrels of oil equivalent.

  17. Comparison of co-seismic and post-seismic slip of large earthquakes in southern Peru and northern Chile

    Science.gov (United States)

    Pritchard, M. E.; Ji, C.; Simons, M.; Klotz, J.

    2003-12-01

    We use InSAR, GPS, and seismic data to constrain the location of co-seismic and post-seismic slip on the subduction interface in southern Peru and northern Chile. We focus on the July 30, 1995, {M}w~8.1 and the January 30, 1998, {M}w~7.1 northern Chile earthquakes as well as the November 12, 1996, {M}w~7.7 and June 23, 2001, {M}w~8.4 southern Peru earthquakes. For all four earthquakes, we invert body-wave seismic waveforms and geodetic data (InSAR for all earthquakes and GPS where available) both jointly and separately for co-seismic slip. In northern Chile, we constrain the temporal and spatial evolution of post-seismic after-slip using about 30 interferograms spanning 1995-2000 and GPS data from the German SAGA array (spanning 1995-1997, including vertical displacements). In southern Peru, we use InSAR data, and GPS data from the Arequipa station to constrain post-seismic after-slip. Comparison of these events provides insight into the rupture process of large subduction zone earthquakes and the mechanisms of post-seismic after-slip. The plate tectonic setting for all the earthquakes is similar (convergence rate, plate age, etc.), but the amount of post-seismic after-slip is different. There is significant slip after the 2001 earthquake (equivalent to approximately 20% of the co-seismic moment), but compared to other recent subduction zone earthquakes, there is little slip following the other three events. The different amounts of post-seismic slip are not obviously related to differences in the dynamic ruptures of each event, but might be related to along-strike variations in material properties (like sediment thickness).

  18. Timing and paleoclimatic significance of Holocene glacier fluctuations in the Cordillera Vilcabamba of southern Peru

    Science.gov (United States)

    Licciardi, J. M.; Taggart, J. R.; Schaefer, J. M.; Lund, D. C.

    2009-12-01

    Past fluctuations in climatically sensitive tropical glaciers provide important insight into regional paleoclimatic trends and forcings, but well-dated chronologies are scarce, particularly during the Holocene. We have established precise cosmogenic 10Be surface exposure ages of moraine sequences in the Cordillera Vilcabamba (13°20’S latitude), located in the outer tropics of southern Peru. Results indicate the dominance of two major glacial culminations and associated climatic shifts in the Vilcabamba, including an early Holocene glacial interval and a somewhat less extensive glaciation late in the ‘Little Ice Age’ (LIA) period. Lichenometric measurements on the youngest moraines support the 10Be ages, but uncertainties in the lichen ages arise from the lack of a local lichen growth curve. The Peruvian glacier chronologies differ from a recently-developed New Zealand record but are broadly correlative with well-dated glacial records in Europe, suggesting climate linkages between the tropics and the North Atlantic region. For the latest Holocene, our leading hypothesis is that climate forcings involving southward migration of the Atlantic Intertropical Convergence Zone can explain concurrent glaciations in tropical South America and northern high latitudes, but the influence of other climate drivers such as the El Niño/Southern Oscillation may have also played a role. Estimated differences between equilibrium-line altitudes (ELAs) on modern glaciers and those inferred for expanded latest Holocene glaciers reveal an ELA rise of 165-200 m since the LIA, suggesting that temperatures 1.1-1.3°C cooler than present could have sustained glaciers at their LIA maximum positions if temperature was the only control, and thus providing an upper bound on temperature depression during the LIA. However, further work is required to constrain the likely role of precipitation changes. These new Peruvian glacier chronologies and ELA reconstructions complement ice core and

  19. Late Quaternary Paleohydrology of the Madre de Dios River, southwestern Amazon Basin, Peru

    Science.gov (United States)

    Rigsby, Catherine A.; Hemric, Erin M.; Baker, Paul A.

    2009-12-01

    Late Quaternary climatic and hydrologic variability triggered changes in fluvial deposition and erosion along the course of the Madre de Dios River, Peru, the largest tributary basin of the Madeira basin, itself the largest tributary basin of the Amazon. Three laterally extensive, Quaternary-age, terrace tracts are present within the Madre de Dios basin. Analysis of sedimentary facies, present in the modern cut banks and terraced sequences, along with radiocarbon dates on fossil wood and leaf material preserved in the terraced strata, allow reconstruction of the Late Quaternary depositional history of the sedimentary sequences, including determination of the approximate timing of aggradation and downcutting episodes and its relationship to the timing of past climate change in this portion of the Amazon basin and beyond. The Quaternary sediments underlying the terraces most often recorded deposition in a coarse-grained meandering fluvial system. The T3 terrace, the highest terrace, is underlain by the Miocene (?) Ipururi Formation, which is unconformably overlain by the late Miocene-Pleistocene (?) (> 48,000 cal yrs BP) Madre de Dios Formation, a multistory coarse-sandy to gravelly channel and point bar complex. The latter was downcut before 29,850 ± 100 cal yrs BP. This downcut landscape was infilled by meandering fluvial strata characterized by gravelly channel deposits in a sequence dominated by floodplain and lateral accretion deposits. These strata were in turn downcut to form the T2 terrace before 11,970 ± 100 cal yrs BP. A third episode of aggradation resulted in the deposition of a sand-dominated meandering channel complex that infilled the T2 valley and was subsequently downcut after 3780 ± 50 cal yrs BP. This most recent terrace is infilled by the modern fluvial sediment, which has been actively aggrading since at least 870 ± 50 cal yrs BP. Importantly, the Madre de Dios fluvial system actively aggraded between 30,000 and 25,000 cal yrs BP, (and likely

  20. Largest explosive eruption in historical times in the Andes at Huaynaputina volcano, a.d. 1600, southern Peru

    Science.gov (United States)

    Thouret, Jean-Claude; Davila, Jasmine; Eissen, Jean-Philippe

    1999-05-01

    The largest explosive eruption (volcanic explosivity index of 6) in historical times in the Andes took place in a.d. 1600 at Huaynaputina volcano in southern Peru. According to chronicles, the eruption began on February 19 with a Plinian phase and lasted until March 6. Repeated tephra falls, pyroclastic flows, and surges devastated an area 70 × 40 km2 west of the vent and affected all of southern Peru, and earthquakes shook the city of Arequipa 75 km away. Eight deposits, totaling 10.2 13.1 km3 in bulk volume, are attributed to this eruption: (1) a widespread, ˜8.1 km3 pumice-fall deposit; (2) channeled ignimbrites (1.6 2 km3) with (3) ground-surge and ash-cloud-surge deposits; (4) widespread co-ignimbrite ash layers; (5) base-surge deposits; (6) unconfined ash-flow deposits; (7) crystal-rich deposits; and (8) late ash-fall and surge deposits. Disruption of a hydrothermal system and hydromagmatic interactions are thought to have fueled the large-volume explosive eruption. Although the event triggered no caldera collapse, ring fractures that cut the vent area point to the onset of a funnel-type caldera collapse.

  1. Large mass movements related to deglaciation effects in southern Peru (Cusco)

    Science.gov (United States)

    Giráldez, Claudia; Choquevilca, Walter; Fernández, Felipe; Frey, Holger; García, Javier; Haeberli, Wilfried; Huggel, Christian; Ludena, Sebastián; Rohrer, Mario; Suarez, Wilson

    2013-04-01

    The Andes of Peru are among the regions most severely affected by glacier and high-mountain hazards over the past 100 years. Large-scale disasters with thousands of people killed are on record, including ice/rock avalanches, debris flows, and glacier lake outburst floods (GLOF's). Effects of climate change such as glacier retreat and formation of glacier lakes have been one of the drivers of hazards in the past. Now, there is an increasing concern about the destabilizing effect that recent and further warming has a on perennially frozen bedrock and on steep glaciers in the steep flanks of high-mountain peaks, with potentially severe consequences to ice/rock avalanches, which may impact existing and new lakes, producing far-reaching outburst floods. Risks are also changing due to the socio-economic development in the Andean region and need to be considered using integrative approaches. Most research so far has concentrated on the Cordillera Blanca region where the most devastating disasters occurred during the 20th century. Very little is known about glacier and high-mountain hazards in the southern Peruvian Cordilleras of Cusco although some of the largest debris flows worldwide affected this region in recent years. In fact, very little is known about the nature, origin and exact dimensions of mass movements in this area, and long-term climatic records are neither available. Here we analyze these recent events in the Santa Teresa region based on field work, satellite images, available meteorological data, and numerical modeling of mass movements. These studies are part of a larger effort towards an integrative risk management. Most of the mass movements that caused disasters have their origin in glaciated catchments draining towards Santa Teresa with catchment sizes between about 100 and 300 km2, and glacier areas of 6 to 16 km2 per catchment. It is known that the enormous 1998 debris flow (ca. 25 million m3) that destroyed the Machu Picchu hydropower plant

  2. Messinian paleoenvironmental changes in the easternmost Mediterranean Basin: Adana Basin, southern Turkey

    OpenAIRE

    FARANDA, Costanza; Gliozzi, Elsa; CIPOLLARI, Paola; Grossi, Francesco; Darbaş, Güldemin

    2013-01-01

    We present detailed Messinian paleoenvironmental reconstructions for the Adana Basin based on a multidisciplinary approach that utilizes the fossil content of the Kuzgun and Handere Formations. To reconstruct the paleoenvironmental changes that affected the Adana Basin during the Messinian, we analyzed mollusk, ostracod, planktonic and benthonic foraminifer, and calcareous nannofossil assemblages from 2 stratigraphic sections near Kabasakal village (Adana, southern Turkey). To determine if th...

  3. Killing the snake of poverty : local perceptions of poverty and well-being and people’s capabilities to improve their lives in the Southern Andes of Peru

    NARCIS (Netherlands)

    A. Miyashita

    2009-01-01

    Despite the generalised image of comuneros of the Southern Andes of Peru as living in poverty, a closer examination of the daily lives of the campesinos provides a more dynamic perspective. Some households claim that their lives are improving, others that their lives are the same, while many report

  4. Neotectonic of subsiding basins : case of studies from Marañon and Beni basins, Peru and Bolivia

    OpenAIRE

    Dumont, Jean-Francois

    1994-01-01

    Climatic conditions make the fluvial processes very sensitive in the extended flood plain of subandean basins, giving typical morphostructures. Because of high subsidence rate, these basins are case for the understanding of neotectonics in subsiding basins. Recent anciente fluvial traces are used in combination with sub surface structures, neotectonic and seismotectonic data to study the neotectonic evolution of the Peruvian and Bolivian active foreland basins. These basins, the Marañon Basin...

  5. Efficacy of sulfadoxine-pyrimethamine and mefloquine for the treatment of uncomplicated Plasmodium falciparum malaria in the Amazon basin of Peru

    Directory of Open Access Journals (Sweden)

    Magill Alan J.

    2004-01-01

    Full Text Available In vivo antimalarial drug efficacy studies of uncomplicated Plasmodium falciparum malaria at an isolated site in the Amazon basin of Peru bordering Brazil and Colombia showed >50% RII/RIII resistance to sulfadoxine-pyrimethamine but no evidence of resistance to mefloquine.

  6. Evaluation of water quality in the Rimac River Basin of Peru: Huaycoloro urban subbasin

    Science.gov (United States)

    Baldeón Quispe, W.; Vela Cardich, R.; Huamán Paredes, F.

    2013-05-01

    In Peru, the increasing water scarcity and quality deterioration caused public health problems and deterioration of ecosystems that are exacerbated during periods of drought. The most populated basin is the Rimac River which rises in the Andes, between 4000 and 6000 meters and flow into the Pacific Ocean. This basin has pollution problems and a clear example is the Huaycoloro urban subbasin that originated in 2005, the creation of multi-sectoral technical committee for the recovery of health and environmental quality of the Huaycoloro subbasin (DIGESA, 2006a). The objective of this work is the need to generate and evaluate information on water quality in the Huaycoloro subbasin, quantifying physicochemical and microbiological parameters in four monitoring stations for a period from October 1, 2006 to April 24, 2010. The monitoring was conducted in the dry season because the Huaycoloro subbasin is a dry riverbed and therefore this is the critical period for evaluation. Initially samples were taken every two weeks during the months of October and November 2006. In 2007 were sampled monthly in April, June and September. In the years 2008, 2009 and 2010 surveys were conducted once a year, in the months of October, May and April respectively. Wide variations in the results of the various parameters analyzed in each of the stations mainly be explained by differences in the frequency of discharge of domestic and industrial effluent without prior treatment, effluent turn change in quantity and quality according to the various processes associated with each activity. Domestic effluents from populations that do not have sewer, industrial effluents from tannery correspond to activities, laundry, dairy, brewing and other. During field trips, we could be determined, in some instances, significant changes in water quality in a short period of time (one hour or less), manifested by changes in color fluctuations of water and the solids content in suspension. We obtained total

  7. Seismic Structure in Southern Peru: Evidence for a Smooth Contortion Between Flat and Normal Subduction of the Nazca Plate

    Science.gov (United States)

    Dougherty, S. L.; Clayton, R. W.

    2014-12-01

    Rapid changes in slab geometry are typically associated with fragmentation of the subducted plate; however, continuous curvature of the slab is also possible. The transition from flat to normal subduction in southern Peru is one such geometrical change, where previous studies have suggested both tearing and continuity of the slab. The morphology of the subducted Nazca plate along this transition is further explored here using intraslab earthquakes recorded by temporary regional seismic arrays. Observations of a gradual increase in slab dip coupled with a lack of any gaps or vertical offsets in the intraslab seismicity suggest a smooth contortion of the slab. Concentrations of focal mechanisms at orientations which are indicative of slab bending are also observed along the change in slab geometry. The presence of a thin ultra-slow velocity layer (USL) atop the horizontal Nazca slab is identified and located. The lateral extent of this USL is coincident with the margin of the projected linear continuation of the subducting Nazca Ridge, implying a causal relationship. Waveform modeling of the 2D structure in southern Peru using a finite-difference algorithm provides constraints on the velocity and geometry of the slab's seismic structure and confirms the absence of any tears in the slab. The seismic and structural evidence suggests smooth contortion of the Nazca plate along the transition from flat to normal subduction. The slab is estimated to have experienced 10% strain in the along-strike direction across this transition, compared to 15% strain across flat-to-normal transitions in central Mexico where the Cocos slab is likely torn.

  8. Genetic analysis of South American eastern equine encephalomyelitis viruses isolated from mosquitoes collected in the Amazon Basin region of Peru.

    Science.gov (United States)

    Kondig, John P; Turell, Michael J; Lee, John S; O'Guinn, Monica L; Wasieloski, Leonard P

    2007-03-01

    Identifying viral isolates from field-collected mosquitoes can be difficult and time-consuming, particularly in regions of the world where numerous closely related viruses are co-circulating (e.g., the Amazon Basin region of Peru). The use of molecular techniques may provide rapid and efficient methods for identifying these viruses in the laboratory. Therefore, we determined the complete nucleotide sequence of two South American eastern equine encephalomyelitis viruses (EEEVs): one member from the Peru-Brazil (Lineage II) clade and one member from the Argentina-Panama (Lineage III) clade. In addition, we determined the nucleotide sequence for the nonstructural P3 protein (nsP3) and envelope 2 (E2) protein genes of 36 additional isolates of EEEV from mosquitoes captured in Peru between 1996 and 2001. The 38 isolates were evenly distributed between lineages II and III virus groupings. However, analysis of the nsP3 gene for lineage III strongly suggested that the 19 isolates from this lineage could be divided into two sub-clades, designated as lineages III and IIIA. Compared with North American EEEV (lineage I, GA97 strain), we found that the length of the nsP3 gene was shorter in the strains isolated from South America. A total of 60 nucleotides was deleted in lineage II, 69 in lineage III, and 72 in lineage IIIA. On the basis of the sequences we determined for South American EEEVs and those for other viruses detected in the same area, we developed a series of primers for characterizing these viruses.

  9. Depositional Record of the Bagua Basin, Northern Peru: Implications for Climate and Tectonic Evolution of Tropical South America

    Science.gov (United States)

    Moreno, F.; George, S. W. M.; Williams, L. A.; Horton, B. K.; Garzione, C. N.

    2015-12-01

    The Andes Mountains exert critical controls on the climate, hydrology, and biodiversity of South America. The Bagua Basin, a low elevation (400-600 m) intermontane basin in northern Peru, offers a unique opportunity to study the ecological, climatic, and structural evolution of the western topographic boundary of the Amazonian foreland. Situated between the Marañon fold-thrust belt of the Western Cordillera and basement block uplifts of the Eastern Cordillera, the Bagua region contains a protracted, semi-continuous record of Triassic through Pleistocene sedimentation. Whereas Triassic-Cretaceous marine deposits were potentially related to extension and regional thermal subsidence, a Paleocene-Eocene shift to shallow marine and fluvial systems marks the onset of foreland basin conditions. Oligocene-Miocene sedimentation corresponds to a braided-meandering fluvial system with exceptional development of paleosols. In this study, we use new detrital zircon U-Pb geochronologic and oxygen stable isotopic datasets to establish a chronology of pre-Andean and Andean processes within the Bagua Basin. Detrital zircon geochronology provides constraints on when the Western and Eastern cordilleras shed sediments into the basin. Syndepositional zircons within Eocene, Oligocene and Miocene strata provide key age control for a previously poorly constrained depositional chronology. Preliminary results suggest a dramatic provenance shift in which Paleocene deposits contain almost exclusively cratonic populations (500-1600 Ma) whereas Eocene deposits show a mix of syndepositional zircons from the magmatic arc, recycled Mesozoic zircons, and cratonic zircon populations. Oxygen stable isotopes (δ18O) of carbonate nodules from Neogene paleosols will help elucidate when the Eastern Cordillera became an orographic barrier intercepting moisture from the Amazon basin to the east. Together, these records will help uncover the history of tectonics and climate interaction in tropical South

  10. Centuries of marine radiocarbon reservoir age variation within archaeological Mesodesma Donacium shells from Southern Peru

    Science.gov (United States)

    Jones, K.B.; Hodgins, G.W.L.; Etayo-Cadavid, M. F.; Andrus, C.F.T.; Sandweiss, D.H.

    2010-01-01

    Mollusk shells provide brief (Peru. The ranges in marine 14C ages (and thus R) from the 2 shells are 530 and 170 14C yr; R from individual aragonite samples spans 130 ?? 60 to 730 ?? 170 14C yr. This intrashell 14C variability suggests that 14C dating of small (time-slice much less than 1 yr) marine samples from a variable-R (i.e. variable-upwelling) environment may introduce centuries of chronometric uncertainty. ?? 2010 by the Arizona Board of Regents on behalf of the University of Arizona.

  11. Pilgrims past and present: the ritual landscape of Raqchi, southern Peru

    Directory of Open Access Journals (Sweden)

    Bill Sillar

    1999-11-01

    Full Text Available In 1533 the Spanish overthrew the Inka1 empire that then dominated the Andean region and much of the west coast of South America. Most tourists going to Peru visit Cuzco and Machu Pichu, but few see any of the other spectacular Ink a ruins, such as the mythical and ritual site at Raqchi. There research is focusing on the site itself and on the long-term history of the Vilcanota Valley, including the changes wrought by the Spanish invasion. The project is also working with the local community to promote sustainable tourism.

  12. Obsidian Hydration at High Elevation: Archaic Quarrying at the Chivay Source, Southern Peru

    OpenAIRE

    Tripcevich, Nicholas; Eerkens, Jelmer W.; Carpenter, Tim R.

    2012-01-01

    We examine obsidian hydration as a means to date archaeological sites at high elevation in the central Andes, and in particular quarry sites that are difficult to date by radiocarbon means. The Chivay obsidian source lies in a volcanic depression above the Colca Valley in Arequipa, Peru (71.5355° E, 15.6423° S) at 4950 masl. We compare obsidian hydration readings from one quarry and two workshop locations. Ninety-one flakes from the quarry pit, and 61 and 33 flakes from the workshops were ana...

  13. Assessment of tsunami hazards for the Central American Pacific coast from southern Mexico to northern Peru

    OpenAIRE

    B. Brizuela; Armigliato, A.; S. Tinti

    2014-01-01

    Central America (CA), from Guatemala to Panama, has been struck by at least 52 tsunamis between 1539 and 2013, and in the extended region from Mexico to northern Peru (denoted as ECA, Extended Central America in this paper) the number of recorded tsunamis in the same time span is more than 100, most of which were triggered by earthquakes located in the Middle American Trench that runs parallel to the Pacific coast. The most severe event in the catalogue is the tsunami that o...

  14. GEODYNAMICS OF NAZCA RIDGE’S OBLIQUE SUBDUCTION AND MIGRATION - IMPLICATIONS FOR TSUNAMI GENERATION ALONG CENTRAL AND SOUTHERN PERU: Earthquake and Tsunami of 23 June 2001

    Directory of Open Access Journals (Sweden)

    George Pararas-Carayannis

    2012-01-01

    Full Text Available Peru is in a region of considerable geologic and seismic complexity. Thrust faulting along the boundary where the Nazca plate subducts beneath the South American continent has created three distinct seismic zones. The angle of subduction of the Nazca oceanic plate beneath the South American plate is not uniform along the entire segment of the Peru-Chile Trench. Furthermore, subduction is affected by buoyancy forces of the bounding oceanic ridges and fractures - such as the Mendana Fracture Zone (MFZ to the North and the Nazca Ridge to the South. This narrow zone is characterized by shallow earthquakes that can generate destructive tsunamis of varied intensities. The present study examines the significance of Nazca Ridge’s oblique subduction and migration to the seismicity of Central/Southern Peru and to tsunami generation. The large tsunamigenic earthquake of 23 June 2001 is presented as a case study. This event generated a destructive, local tsunami that struck Peru’s southern coasts with waves ranging from 3 to 4.6 meters (10-15 feet and inland inundation that ranged from 1 to 3 km. In order to understand the near and far-field tsunamigenic efficiency of events along Central/Southern Peru and the significance of Nazca Ridge’s oblique subduction, the present study examines further the geologic structure of the region and this quake’s moment tensor analysis, energy release, fault rupture and the spatial distribution of aftershocks. Tsunami source mechanism characteristics for this event are presented, as inferred from seismic intensities, energy releases, fault plane solutions and the use of empirical relationships. The study concludes that the segment of subduction and faulting paralleling the Peru-Chile Trench from about 150 to 180 South, as well as the obliquity of convergent tectonic plate collision in this region, may be the reason for shorter rupture lengths of major earthquakes and the generation of only local destructive tsunamis.

  15. Subsidence and basin development in the southern Oklahoma aulacogen

    Energy Technology Data Exchange (ETDEWEB)

    Ferebee, C. (Univ. of Tulsa, OK (United States))

    1991-03-01

    Development of the southern Oklahoma aulacogen was the result of Cambrian tectonism along Proterozoic zones of weakness that caused northwest-trending extensional normal faults related to a rifting event. These faults were reactivated during upper Paleozoic compressional stress with fault patterns indicative of sinistral transpressive and transtensional movement. Mapping in the region has allowed classification of the myriad of faults into six major systems, from the north to south: the Washita Valley, Madill-Aylesworth, Caddo, Criner, Horseshoe Bend, and Muenster systems. Development of the fault systems occurred somewhat independently as energy was transferred between them owing to changes in stress from the uneven collision of the Ouachita front. This model may account for the episodic movement recognized by past investigators. The determination of relative timing of development within these systems has shown that the Madill-Aylesworth and Criner systems were active during the Upper Mississippian. As deformation continued along the Criner system structural activity moved southward to include the Horseshoe Bend and Muenster systems during the Early Pennsylvanian. During the Middle Pennsylvanian, fault development along the southern margin of the aulacogen subsided, and deformation activity was initiated in the northern portions of the Ardmore basin. The amount of horizontal displacement along fault systems in the region is still unresolved. However, by regional mapping along the Criner systems, a minimum of 6 mi left-lateral movement can be documented as having occurred during the Upper Pennsylvanian using models of sediment deposition and transport in strike-slip basins.

  16. El Niño-Southern Oscillation-based index insurance for floods: Statistical risk analyses and application to Peru

    Science.gov (United States)

    Khalil, Abedalrazq F.; Kwon, Hyun-Han; Lall, Upmanu; Miranda, Mario J.; Skees, Jerry

    2007-10-01

    Index insurance has recently been advocated as a useful risk transfer tool for disaster management situations where rapid fiscal relief is desirable and where estimating insured losses may be difficult, time consuming, or subject to manipulation and falsification. For climate-related hazards, a rainfall or temperature index may be proposed. However, rainfall may be highly spatially variable relative to the gauge network, and in many locations, data are inadequate to develop an index because of short time series and the spatial dispersion of stations. In such cases, it may be helpful to consider a climate proxy index as a regional rainfall index. This is particularly useful if a long record is available for the climate index through an independent source and it is well correlated with the regional rainfall hazard. Here El Niño-Southern Oscillation (ENSO) related climate indices are explored for use as a proxy to extreme rainfall in one of the districts of Peru, Piura. The ENSO index insurance product may be purchased by banks or microfinance institutions to aid agricultural damage relief in Peru. Crop losses in the region are highly correlated with floods but are difficult to assess directly. Beyond agriculture, many other sectors suffer as well. Basic infrastructure is destroyed during the most severe events. This disrupts trade for many microenterprises. The reliability and quality of the local rainfall data are variable. Averaging the financial risk across the region is desirable. Some issues with the implementation of the proxy ENSO index are identified and discussed. Specifically, we explore (1) the reliability of the index at different levels of probability of exceedance of maximum seasonal rainfall, (2) the effect of sampling uncertainties and the strength of the proxy's association to local outcome, (3) the potential for clustering of payoffs, (4) the potential that the index could be predicted with some lead time prior to the flood season, and (5) evidence

  17. Alluvial plain dynamics in the southern Amazonian foreland basin

    Directory of Open Access Journals (Sweden)

    U. Lombardo

    2015-10-01

    Full Text Available Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation is primarily the result of river crevasse splays triggered by above normal precipitation events due to La Niña. However, more than 90 % of the Amazonian river network is made of small rivers and it is unknown whether small river floodplain sedimentation is influenced by the ENSO cycle as well. Using Landsat images from 1984 to 2014, here I analyse the behaviour of all the twelve tributaries of the Río Mamoré with a catchment in the Andes. I show that these are very active rivers and that the frequency of crevasses is not linked to ENSO activity. I found that most of the sediments eroded from the Andes by the tributaries of the Mamoré are deposited in the alluvial plains, before reaching the parent river. The mid- to late Holocene paleo-channels of these rivers are located tens of kilometres further away from the Andes than the modern crevasses. I conclude that the frequency of crevasses is controlled by intrabasinal processes that act on a year to decade time scale, while the average location of the crevasses is controlled by climatic or neo-tectonic events that act on a millennial scale. Finally, I discuss the implications of river dynamics on rural livelihoods and biodiversity in the Llanos de Moxos, a seasonally flooded savannah covering most of the southern Amazonian foreland basin and the world's largest RAMSAR site.

  18. Alluvial plain dynamics in the southern Amazonian foreland basin

    Science.gov (United States)

    Lombardo, Umberto

    2016-05-01

    Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation is primarily the result of river crevasse splays and sheet sands triggered by above-normal precipitation events due to La Niña. However, more than 90 % of the Amazonian river network is made of small rivers and it is unknown whether small river floodplain sedimentation is influenced by the ENSO cycle as well. Using Landsat images from 1984 to 2014, here I analyse the behaviour of all 12 tributaries of the Río Mamoré with a catchment in the Andes. I show that these are very active rivers and that the frequency of crevasses is not linked to ENSO activity. The data suggest that most of the sediments eroded from the Andes by the tributaries of the Mamoré are deposited in the alluvial plains, before reaching the parent river. The mid-to-late Holocene paleo-channels of these rivers are located tens of kilometres further away from the Andes than the modern crevasses. I conclude that the frequency of crevasses is controlled by intrabasinal processes that act on a yearly to decadal timescale, while the average location of the crevasses is controlled by climatic or neo-tectonic events that act on a millennial scale. Finally, I discuss the implications of river dynamics on rural livelihoods and biodiversity in the Llanos de Moxos, a seasonally flooded savannah covering most of the southern Amazonian foreland basin and the world's largest RAMSAR site.

  19. Along-strike variations in post-seismic deformation in northern Chile and southern Peru

    Science.gov (United States)

    Pritchard, M. E.; Simons, M.

    2004-12-01

    We use InSAR and GPS data to constrain the spatio-temporal evolution of post-seismic after-slip following three large subduction zone earthquakes in South America. Post-seismic deformation following the 1995 {M}w~8.1 Antofagasta, Chile earthquake is barely above the InSAR detection limit, but by combining GPS observations with 36 interferograms we model the post-seismic deformation between the years 1995-2000. If the deformation is after-slip on the fault interface, the equivalent moment magnitude is 10-20% of the co-seismic moment, with the maximum deformation occurring 100 km from the maximum co-seismic slip. There is a pulse of deformation between large aftershocks in 1996 and 1998 that appears distinct from the general decay of after-slip with time. The low magnitude of post-seismic deformation is anomalous compared to other recent subduction zone earthquakes, including the nearby 2001 {M}w~8.4 Arequipa, Peru earthquake. After-slip following the 2001 earthquake between 2001-2004 equals about 20-40% of the co-seismic moment. There is no definitive post-seismic deformation following the 1996 {M}w~7.7 Nazca, Peru earthquake between 1997-1999, although there is no data spanning the first 51 days after the earthquake. Variations in the depth of rupture during these three earthquakes cannot solely explain the variations in after-slip. We suggest that variations in sediment subducted in each location may control the magnitude of after-slip. The larger thickness of sediments in the region of the 2001 earthquake might also explain why observed after-slip is located in the same area as the co-seismic slip, instead of down-dip, as in other subduction zones.

  20. Upper plate deformation and seismic barrier in front of Nazca subduction zone: The Chololo Fault System and active tectonics along the Coastal Cordillera, southern Peru

    Science.gov (United States)

    Audin, Laurence; Lacan, Pierre; Tavera, Hernando; Bondoux, Francis

    2008-11-01

    The South America plate boundary is one of the most active subduction zone. The recent Mw = 8.4 Arequipa 2001 earthquake ruptured the subduction plane toward the south over 400 km and stopped abruptly on the Ilo Peninsula. In this exact region, the subduction seismic crisis induced the reactivation of continental fault systems in the coastal area. We studied the main reactivated fault system that trends perpendicular to the trench by detailed mapping of fault related-geomorphic features. Also, at a longer time scale, a recurrent Quaternary transtensive tectonic activity of the CFS is expressed by offset river gullies and alluvial fans. The presence of such extensional fault systems trending orthogonal to the trench along the Coastal Cordillera in southern Peru is interpreted to reflect a strong coupling between the two plates. In this particular case, stress transfer to the upper plate, at least along the coastal fringe, appears to have induced crustal seismic events that were initiated mainly during and after the 2001 earthquake. The seafloor roughness of the subducting plate is usually thought to be a cause of segmentation along subduction zones. However, after comparing and discussing the role of inherited structures within the upper plate to the subduction zone segmentation in southern Peru, we suggest that the continental structure itself may exert some feedback control on the segmentation of the subduction zone and thus participate to define the rupture pattern of major subduction earthquakes along the southern Peru continental margin.

  1. New dactylogyrids (Monogenea) parasitizing the gills of catfishes (Siluriformes) from the Amazon River basin in Peru.

    Science.gov (United States)

    Mendoza-Franco, Edgar F; Scholz, T

    2009-08-01

    Three dactylogyrid (Monogenea) species are described from the gills of siluriform fishes from the rivers around Iquitos, tributaries of the Amazon River in Peru: Demidospermus centromochli n. sp. from Centromochlus heckelii (de Filippi) (Auchenipteridae) and Demidospermus macropteri n. sp. and Ameloblastella unapi n. sp. from Calophysus macropterus (Lichtenstein) (Pimelodidae). The new species of Demidospermus differ from their congeners in having 2 different hook shapes. Ameloblastella unapi n. sp. differs from the other 3 species of the genus in having anchors with an elongate, straight shaft and a short point that forms a 90 degrees angle, a coiled (counterclockwise) male copulatory organ with 13-14 rings, and a coiled vaginal tube. Based on the present study, Pseudovancleaveus Franca, Issac, Pavanelli, and Takemoto, 2003, is regarded as a junior subjective synonym of Ameloblastella Kritsky, Mendoza-Franco, and Scholz, 2000. The finding of Demidospermus and Ameloblastella spp. on these siluriforms extends our host and geographic knowledge of species of these monogenean genera to Peru. PMID:19215149

  2. Hydrological WEAP Modeling of the Upper Basin of the Apurimac River Basin, in Peru. An Assessment of Available Water Resources and Supply

    Science.gov (United States)

    Yi, S.; Sandoval Solis, S.

    2015-12-01

    Designing sustainable water resources systems is challenging given the natural scarcity of this resources in certain region and the increasing anthropogenic water demand for economic purposes. The overall goal of this study is to develop an empirical hydrologic model (one bucket model) that can adequately represent the hydrology and water resources management in the Apurimac River Basin (ARB) in Peru. The specific objectives are to: (a) develop the empirical hydrologic model, calibrate and validate it (b) build a water allocation model (c) evaluate their water supply performance with different series of scenarios (i) current and future water demands, (ii) with and without the construction of the reservoir under different hydrologic conditions (normal, dry and wet). Water Evaluation And Planning (WEAP) was used to build the model and evaluate different water allocation strategies, new infrastructure, and assess current and future water needs based on the requirement of the Regional Government of Cuzco and Arequipa. The proposed hydrologic model is a one-bucket model, where the processes of direct runoff, interflow and baseflow are represented and the process of groundwater recharge is the vertical outflow from the bottom of the bucket. Also, this model includes groundwater component which is an imperative process to consider in the valley of this basin because it provides adequate results, as shown later for this basin. Water allocation model estimate the quantity of water available to different demand sites within a river basin at different times. This study explains their impact in the analysis of the water availability and water supply for current and future water demands in the ARB with and without reservoir.

  3. Assessment of tsunami hazards for the Central American Pacific coast from southern Mexico to northern Peru

    Science.gov (United States)

    Brizuela, B.; Armigliato, A.; Tinti, S.

    2014-07-01

    Central America (CA), from Guatemala to Panama, has been struck by at least 52 tsunamis between 1539 and 2013, and in the extended region from Mexico to northern Peru (denoted as ECA, Extended Central America in this paper) the number of recorded tsunamis in the same time span is more than 100, most of which were triggered by earthquakes located in the Middle American Trench that runs parallel to the Pacific coast. The most severe event in the catalogue is the tsunami that occurred on 2 September 1992 off Nicaragua, with run-up measured in the range of 5-10 m in several places along the Nicaraguan coast. The aim of this paper is to assess the tsunami hazard on the Pacific coast of this extended region, and to this purpose a hybrid probabilistic-deterministic analysis is performed, that is adequate for tsunamis generated by earthquakes. More specifically, the probabilistic approach is used to compute the Gutenberg-Richter coefficients of the main seismic tsunamigenic zones of the area and to estimate the annual rate of occurrence of tsunamigenic earthquakes and their corresponding return period. The output of the probabilistic part of the method is taken as input by the deterministic part, which is applied to calculate the tsunami run-up distribution along the coast.

  4. Prevalence and risk factors associated to Eimeria spp. infection in unweaned alpacas (Vicugna pacos) from Southern Peru.

    Science.gov (United States)

    Díaz, Pablo; Panadero, Rosario; López, Rosalía; Cordero, Aida; Pérez-Creo, Ana; López, Ceferino M; Fernández, Gonzalo; Díez-Baños, Pablo; Morrondo, Patrocinio

    2016-01-01

    A total of 350 faecal samples from unweaned alpacas over 3 months of age were collected from 23 herds in order to determine the prevalence of Eimeria spp. in Southern Peru and to identify the risk factors associated to Eimeria infection in young alpacas. Samples were examined by a flotation technique and the identification of risk factors was assessed by a logistic regression analysis. Sixty four percent of the examined animals shed Eimeria oocysts; herd prevalence was 96%, with an intra-herd prevalence of 60% (range 5.9-100%). Five different Eimeria species were identified, being E. lamae (91%), E. alpacae (87%) and E. punoensis (78%) the most prevalent; E. macusaniensis (35%) and E. ivitaensis (13%) were less common. Mixed-species infections were more frequent (78%) than single infections (22%). E. lamae was the most common monospecific infection and E. lamae/E. alpacae the most frequent association. The geographical area has a significant effect on Eimeria infection rates (74.9% wet Puna vs 37.4% dry Puna) as well as the breeding system (65.1% traditional vs 63.8% modern). In contrast, the sex of the animals (64.6% males vs 64.0% females) showed no influence on the prevalence of infection by Eimeria. The high prevalence found at both individual and herd level and the common presence of highly pathogenic Eimeria species may lead to important economic losses for alpaca breeders and could require the implementation of suitable control measures.

  5. 3D Geologic Model of the Southern Great Basin

    Science.gov (United States)

    Wagoner, J. L.; Myers, S. C.

    2006-12-01

    We have constructed a regional 3D geologic model of the southern Great Basin, in support of a seismic wave propagation investigation of the 1993 Nonproliferation Experiment (NPE) at the Nevada Test Site (NTS). The model is centered on the NPE and spans longitude -119.5° to -112.6°, latitude 34.5° to 39.8°, and a depth from the surface to 150 km below sea level. Hence, the model includes the southern half of Nevada, as well as parts of eastern California, western Utah, and a portion of northwestern Arizona. The upper crust is constrained by geologic and geophysical studies, and the lower crust and upper mantle are constrained by geophysical studies. The upper crustal geologic units are Quaternary basin fill, Tertiary deposits, pre-Tertiary deposits, intrusive rocks, and calderas. The lower crust and upper mantle are parameterized with 8 layers, including the Moho. Detailed geologic data, including surface maps, borehole data, and geophysical surveys, were used to define the geology at the NTS. Digital geologic outcrop data were available for both Nevada and Arizona, whereas we scanned and hand digitized geologic maps for California and Utah. Published gravity data (2km spacing) were used to determine the thickness of the Cenozoic deposits and constrain the depth of the basins. The free surface is based on a 10m lateral resolution DEM at the NTS and a 90m resolution DEM elsewhere. The gross geophysical structure of the crust and upper mantle is taken from regional surface-wave studies. Variations in crustal thickness are based on receiver function analysis and a compilation of reflection/refraction studies. We used the Earthvision (Dynamic Graphics, Inc.) software to integrate the geologic and geophysical information into a model of x,y,z,p nodes, where p is an integer index representing the geologic unit. For regional seismic simulations we convert this realistic geologic model into elastic parameters. Upper crustal units are treated as seismically homogeneous

  6. Neogene coupling between Kuqa Basin and Southern Tien Shan Orogen, Northwestern China

    Institute of Scientific and Technical Information of China (English)

    何光玉; 陈汉林

    2004-01-01

    Based on the sedimentary and subsiding features of Kuqa foreland basin, this paper presents the following characteristics of Neogene coupling relationship between Kuqa Basin and Southern Tien Shan Orogen, Northwestern China:(l) The Southern Tien Shan Orogen underwent Neogene uplifting of 4 km in height and the Kuqa Basin underwent Neogene subsidence of 4-6 km in depth accordingly beginning in 25 Ma; (2) The Southern Tien Shan Orogen moved continuously toward the Kuqa Basin, with largest structural shortening rate of greater than 53.7%, and the north boundary of the Kuqa Basin retreated continuously southward accordingly since the Miocene; (3) There are two subsidence centers with high subsiding rates and large subsiding extent, located in the eastern and western Kuqa Basin respectively, with the subsiding maximizing in the deposition period of Kuqa Formation.

  7. Fungal and Prokaryotic Activities in the Marine Subsurface Biosphere at Peru Margin and Canterbury Basin Inferred from RNA-Based Analyses and Microscopy.

    Science.gov (United States)

    Pachiadaki, Maria G; Rédou, Vanessa; Beaudoin, David J; Burgaud, Gaëtan; Edgcomb, Virginia P

    2016-01-01

    The deep sedimentary biosphere, extending 100s of meters below the seafloor harbors unexpected diversity of Bacteria, Archaea, and microbial eukaryotes. Far less is known about microbial eukaryotes in subsurface habitats, albeit several studies have indicated that fungi dominate microbial eukaryotic communities and fungal molecular signatures (of both yeasts and filamentous forms) have been detected in samples as deep as 1740 mbsf. Here, we compare and contrast fungal ribosomal RNA gene signatures and whole community metatranscriptomes present in sediment core samples from 6 and 95 mbsf from Peru Margin site 1229A and from samples from 12 and 345 mbsf from Canterbury Basin site U1352. The metatranscriptome analyses reveal higher relative expression of amino acid and peptide transporters in the less nutrient rich Canterbury Basin sediments compared to the nutrient rich Peru Margin, and higher expression of motility genes in the Peru Margin samples. Higher expression of genes associated with metals transporters and antibiotic resistance and production was detected in Canterbury Basin sediments. A poly-A focused metatranscriptome produced for the Canterbury Basin sample from 345 mbsf provides further evidence for active fungal communities in the subsurface in the form of fungal-associated transcripts for metabolic and cellular processes, cell and membrane functions, and catalytic activities. Fungal communities at comparable depths at the two geographically separated locations appear dominated by distinct taxa. Differences in taxonomic composition and expression of genes associated with particular metabolic activities may be a function of sediment organic content as well as oceanic province. Microscopic analysis of Canterbury Basin sediment samples from 4 and 403 mbsf produced visualizations of septate fungal filaments, branching fungi, conidiogenesis, and spores. These images provide another important line of evidence supporting the occurrence and activity of fungi in

  8. Pampa del Palo: an anomalous composite marine terrace on the uprising coast of southern Peru

    Science.gov (United States)

    Ortlieb, L.; Zazo, C.; Goy, J. L.; Dabrio, C.; Macharé, J.

    1996-11-01

    Quaternary sediments along the southern Perúvian coast occur as staircase terraces of coastal and shallow-marine deposits in response to continuous uplift related to the active boundary between the Nazca and South-American plates. However, near ILO (in the same coastal stretch) the emergent Pampa del Palo terrace consists of a relatively-thick, vertical stack of shallow-marine, coastal and lagoonal deposits that indicate a rather different geodynamic behaviour. Coastal deposits are correlatable with the successive marine highstands of isotopic stages 7 (?) and 5 (substages 5e and 5c). Combining aerial photo-interpretation, geomorphological mapping, sedimentological analysis, chronostratigraphical data, and structural observations, the Pampa del Palo feature is interpreted as a faulted block that moved independently of the remaining southern Peruvian coast and, for some time between the end of Middle Pleistocene (before ca. 220 ka) and the early Late Pleistocene (ca. 120 ka), it rose more slowly or was even down-faulted relative to the rest of the southern Peruvian margin. The independent block movements ceased after substage 5e, when the Pampa del Palo "terrace" was incorporated into the regional uplift of the area. Since ca. 100 ka, measured uplift rates in the Ilo area amounted up to {160 mm}/{10 3y } when the area has been affected by a few active, NE-SE trending faults only.

  9. Volcanic and glacial evolution of Chachani-Nocarane complex (Southern Peru) deduced from the geomorphologic map.

    Science.gov (United States)

    Alcalá, J.; Zamorano, J. J.; Palacios, D.

    2012-04-01

    The Chachani-Nocarane (16°11'S; 71°31'W; 6.057 m asl) is a large volcanic complex located in the western Central-Andean Cordillera, South of Peru. The date of the last eruption is not known and there are no registers of recent volcanic activity. The complex is shaped by glacial forms belonging to different phases, and periglacial forms (several generations of rock glaciers) which alternate with volcanic forms. The aim of this research is to establish the glacio-volcanic evolution of the volcanic complex Chachani-Nocarane. In order to do so, a detailed 1:20.000 scale geomorphological map was elaborated by integrating the following techniques: interpretation of the 1:35.000 scale aerial photographs (Instituto Geográfico Nacional de Perú, 1956) and the analysis of satellite images (Mrsid; NASA, 2000). Finally, the cartography was corrected though field work campaigns. Through the geomorphologic analysis of the landforms and their relative position, we have identified twelve phases, seven volcanic and five glacial phases. The most ancient volcanic phase is locate to the north area of the study area and correspond with Nocarane and Chingana volcanoes, alignment NW-SE. Above those ensemble the rest of the large delimited geomorphological units overlap. The most recent is located to the SW and consists of a complex series of domes, lava cones and voluminous lavas. Within the glacial phases, the most ancient one is related to the Last Glacial Maximum during the Pleistocene. Over this period, glaciers formed moraines from 3150 to 3600 m asl. The most recent glacier pulsation corresponds to the Little Ice Age (LIA). The moraines related to that event are the closest to the summits, located between 5.100 and 5.300 m asl, and they represent the last trace of glacial activity on the volcanic complex. Currently, this tropical mountain does not have glaciers. The only solid-state water reserves are found in the form of permafrost, as shown by various generations of rock

  10. Shortening Record in the Central Andean Plateau of Southern Peru: Basement Inversion, Thin-skinned Thrusting, and Geomorphic Response

    Science.gov (United States)

    Perez, N.; Horton, B. K.; McQuarrie, N.; Stübner, K.; Ehlers, T. A.

    2015-12-01

    Variations in the inherited structural architecture along western South America influence the timing, magnitude, and style of Andean deformation and topographic evolution. New results from mapping, balanced cross-section construction, apatite and zircon (U-Th)/He thermochronology, and geomorphology spanning the Altiplano, Eastern Cordillera and Subandean zone of southern Peru define the role of Triassic rift inversion on Cenozoic deformation style, thrust belt kinematics, exhumation timing, and spatial variation of canyon incision. A minimum of 130 km (38%) shortening along a 200 km transect accommodated by thin- and thick-skinned structures involved selective reactivation of Triassic normal faults that fed slip to shallower detachments of thin-skinned fold-thrust systems. Map relationships define unique structural domains defined by inherited normal faults. In the Eastern Cordillera, new zircon (U-Th)/He results from a Triassic pluton reveal Oligocene-Miocene (~26-18 Ma) cooling, consistent with previously reported exhumation from ~40 km along strike to the NW. However, rapid ~15 Ma cooling revealed by new apatite (U-Th)/He data is ~11 Myr older than equivalent rocks in a similar structural setting ~40 km to the NW. This suggests a potential middle Miocene shift from synchronous to diachronous exhumation along strike. Modern fluvial profiles constructed along the Eastern Cordillera show a reduction in knickpoint elevations from SE to NW, suggesting more youthful uplift toward the NW, comparable to the spatial trend in apatite (U-Th)/He ages. The deformation front reached the Subandean zone by ~15 Ma, after the majority of reported deformation in the Eastern Cordillera and Altiplano. These variations in exhumation over such distances are consistent with multiple potential scenarios: a northward propagating wave of uplift, spatial variations in climatically driven incision, interactions with mantle dynamics, or complex structural geometries.

  11. Crude oil geochemistry of the southern Songliao Basin

    Energy Technology Data Exchange (ETDEWEB)

    Li Taiming; Rullkoetter, J.; Radke, M.; Schaefer, R.G.; Welte, D.H.

    1987-08-01

    Twenty-three crude oils from the southern Songliao Basin, Heilongjiang Province (People's Republic of China), were characterized by various organic geochemical techniques to have a very uniform bulk and molecular composition in terms of source characteristics (type I kerogen) but to vary significantly in thermal maturity. Two middle Cretaceous source rocks, i.e. the Members 1 of the Qingshankou (Qn/sub 1/) and Nenjiang (Nen/sub 1/) Formations, were considered to be the most likely origin of the oils investigated, but a Jurassic source cannot be fully excluded for the Nang'An oils. Molecular maturation indicators including carbon preference indices, sterane isomerisation, conversion of mono- into triaromatic steroid hydrocarbons, relative concentration of diasteranes and the 18..cap alpha..(H)-22,29,30-trisnorneohopane/17..cap alpha..(H)-22,29,30-trisnorhopane ratio showed that there is a positive correlation between thermal maturity of the oils and the age of their reservoirs. This was interpreted as an indication of limited cross-stratigraphic migration and further evidence for the generation in the Qn/sub 1/ and Nen/sub 1/ source rocks.

  12. Seismological investigations in the Gioia Tauro Basin (southern Calabria, Italy

    Directory of Open Access Journals (Sweden)

    S. Gresta

    2008-06-01

    Full Text Available This study provides new seismological information to characterize the seismically active area of the Gioia Tauro basin (southern Calabria, Italy. Seismic activity recorded by a temporary network from 1985 to 1994 was analyzed for focal mechanisms, stress tensor inversion, P-wave seismic attenuation and earthquake source parameters estimation. Fault plane solutions of selected events showed a variety of different mechanisms, even if a prevalence of normal dip-slip solutions with prevalent rupture orientations occurring along ca. NE-SW directions was observed. Stress tensor inversion analysis disclosed a region governed mainly by a NW-SE extensional stress regime with a nearly vertical ?1. These results are consistent with the structure movements affecting the studied area and with geodetic data. Furthermore, evaluation of P-waves seismic attenuation and earthquake source parameters of a subset of events highlighted a strong heterogeneity of the crust and the presence of fault segments and/or weakened zones where great stress accumulation or long-rupture propagation are hindered.

  13. Geomorphic evidences of recent tectonic activity in the forearc, southern Peru

    Directory of Open Access Journals (Sweden)

    L. Audin

    2006-12-01

    Full Text Available As the Andean forearc is not concentrating as much tectonic shortening as the foreland (since Middle Miocene and as GPS measurements can not inform on the long-term deformation but rather describe the elastic response of the Andean forearc (Nazca-South American convergence, little is known about the active deformation in the Central Andes Pacific lowlands. However, geomorphic evidences of recent tectonic activity are observed from the Coastal Cordillera to the piedmont of the Western Cordillera. In this paper we analyze this Quaternary tectonic activity in the southern Peruvian forearc, from 17°S to 18°30'S. Examination of aerial photographs and satellite data, and focused field work not only confirms that there is recent tectonic activity but also has revealed the presence of additional active structures that should be taken into account in the description of Andean deformation. In response to active tectonics, these tectonic structures affected very young terraces and Quaternary pediments in the southern Peruvian forearc. We discuss some of the strong geomorphic signatures, such as active fault traces, scarplets, sag ponds, river terraces and some major and minor landslides, which are indicative of active tectonics in this area. Mapping of fault trace geometry and identifying recent surface offsets are used to determine the key places where active tectonics can be involved in the deformation of the forearc, either through normal faulting, strike-slip faults or thrust faults. Among those major tectonic features, some are likely due to seismic crustal activity (along the ongoing Andean tectonic processes and some to relaxation processes of the stress imposed on the outer forearc area after each major subduction earthquakes.

  14. Competition, Cooperation, and the Emergence of Regional Centers in the Northern Lake Titicaca Basin, Peru

    OpenAIRE

    Levine, Abigail Ruth

    2012-01-01

    Regional centers with dense populations developed in the Titicaca Basin during the late Middle (ca. 1300-500 BC) and early Upper Formative (ca. 500 BC- AD 400) Periods. These aggregated settlements have long been considered the hallmark of intermediate societies. This dissertation focuses on the transition from small village societies to ones with pronounced social, political, and economic hierarchies. In the northern Titicaca region, only two sites--Taraco and Pukara--became powerful cent...

  15. History of petroleum systems in the southern part of the Broad Fourteens Basin

    NARCIS (Netherlands)

    Verweij, J.M.; Simmelink, H.J.; Balen, R.T. van; David, P.

    2003-01-01

    2D Basin modelling was used to evaluate the response of source rock maturation, and of petroleum expulsion, migration, accumulation and preservation to the evolution of the southern part of the inverted Broad Fourteens Basin. Modelling results show that the temperature, maturation and petroleum gene

  16. Reforestation and land use change in a drainage basin of southern Italy

    OpenAIRE

    D’Ippolito A; Ferrari E; Iovino F; Nicolaci A; Veltri A

    2013-01-01

    In this study, the land use change in a large basin of Calabria region (southern Italy) subjected to extensive reforestation at the end of the ’50 has been carefully reconstructed and compared with the current situation. The runoff capacity of the basin was estimated using data available for the temporal periods before and after the reforestation interventions. The results show that the surface of the basin interested by former reforestation activities did not affect the runoff, probably due ...

  17. Stratigraphic evolution, structural framework and remaining potential of Talara Basin production units (NW Peru) in Block X area; Evolucao estratigrafica, arcabouco estrutural e potencial remanescente das unidades produtoras da Bacia de Talara (noroeste do Peru) na area do Lote X

    Energy Technology Data Exchange (ETDEWEB)

    Daudt, Jose Alfredo Borges [Petrobras America Inc., Lima (Peru); Pozo, Eloy Gerardo; Torres, Kevin Michael; Ore, Juan Leyva [Petrobras Energia Peru, Lima (Peru)], Emails: eloy.pozo@petrobras.com; kevin.torres@petrobras.com

    2009-11-15

    This article presents the stratigraphic evolution of the Mesozoic-Cenozoic sedimentary section in the Talara Basin (NW Peru) in the Block X area. Furthermore it comments on the structural framework and the remaining hydrocarbon potential in this concession. A brief review of the Talara Basin history is introduced, highlighting the importance of this basin for the Latin-American Oil Industry. Talara is a forearc basin with complex stratigraphic and structural development. The Block X area is located in a proximal position within the basin where erosive and by-pass events were frequent during the whole basin evolution. A thick load of sediments, favored by a significant subsidence, was deposited in this area, especially during Ypresian and Lutetian. Extensional tectonics, represented by normal faults, compartmentalised the reservoirs in Block X, based on the interpretation considered until now. However, the hypothesis of transcurrent movements was also brought into the discussion by some authors, although this had very little surface and subsurface evidence to support it. The presented stratigraphic model is based on observations and interpretations of well logs and outcrops, considering the sequence stratigraphic paradigms. The interpreted sequences hierarchical framework was approached in a more 'neutral' way to avoid rigid time scales commonly adopted by the industry. Thus, the model is made of low frequency sequences with boundaries defined by the most important paleo-ambiental shifts, and high frequency sequences where boundaries were defined considering more subtle variations. Regarding the remaining potential, the Block X area is still forecasting a good exploration and exploitation potential, even considering more than 100 years of productive history. Several secondary recovery projects and shorter-acreage drilling programs have been implemented since 2003, with excellent results. (author)

  18. Geomorphologic map and derived geomorphological evolution model of the Ampato volcanic complex (Southern Peru).

    Science.gov (United States)

    Alcalá, J.; Zamorano, J. J.; Palacios, D.

    2012-04-01

    In this work we present the evolution of the Ampato volcanic complex (15°24´-15° 51´S, 73°W; 6.288 m asl) from a geomorphological perspective based on the analysis of landforms, both volcanic and derived from cold processes such as moraines and rock glaciers. In order to do so, a detailed 1:20.000 scale geomorphological map was elaborated by integrating the following techniques: the interpretation of the 1:35.000 scale aerial photographs (Instituto Geográfico Nacional de Perú, 1956) and the analysis of satellite images (Mrsid; NASA, 2000). The cartography was corrected through field work campaigns. A geomorphological cross-section traversing the map from North to South was elaborated in order facilitate the interpretation of the landforms. From the thorough analysis of the landforms represented in the geomorphological map and their relative position we have identified six main volcanic phases, mainly constructive but also, to a lesser extent, destructive (related with a Sant. Helens eruption), interspersed by five large glacial phases. From the three andesitic stratovolcanoes that form the complex (HualcaHualca, Sabancaya and Ampato) we suggest that the oldest of them is HualcaHualca representing the first step of the process over which the other units were placed. The most recent phase corresponds to the main cone of Sabancaya and its sets of domes and large lavas flows. Also we have detected a number of well-preserved vents on the Southern slope of volcano HualcaHualca close to the 1955 glacier tongues. Their presence is an evidence of recent volcanic activity in a volcano considered extinct. The glacial activity has been very active during the Quaternary on the Ampato Complex. The most ancient glacial phase is linked to the Last Glacial Maximum of the Pleistocene. During this event, the paleoglaciers descended down to 3650 m asl and builted moraines of 25- 30 m height. The most recent advance is related to the global event known as Little Ice Age (LIA

  19. Holocene Climate and Landscape Interactions in the Lake Titicaca Basin, Peru

    Science.gov (United States)

    Rigsby, C. A.; Baker, P. A.; Aldenderfer, M. S.

    2001-12-01

    Fluvial strata and landforms in the Rio Ilave valley (Peru) document a history of Holocene aggradation and downcutting that is correlative with regional climatic events. Periods of aggradation correspond to periods of high (or rising) level in Lake Titicaca, increased sediment accumulation in the Ilave delta, and lacustrine sedimentation in the Rio Desaguadero valley. Downcutting episodes correspond to periods of low level in Lake Titicaca, low or rapidly decreasing sedimentation rates in the Ilave delta, and fluvial activity in the Rio Desaguadero valley. The five terrace tracts (T1 through T5) present in this southwestern Lake Titicaca tributary occur as both paired and unpaired terraces and have average heights from 1.4 m to 24.3 m above the valley floor. Radiocarbon dates from the oldest exposed terrace strata and from the top of T4 suggest that the majority of the fluvial sequence was deposited during the time period from the LGM until about 8300 cal BP - a period of generally high precipitation on the Altiplano and high water level in Lake Titicaca. Increased fluvial/glacial runoff during this time resulted in an increased supply of sediment to the Rio Ilave and high sediment accumulation rates offshore from the Ilave delta. With the input of large volumes of easily eroded volcanic-rich sediment from source areas in the Cordillera Occidental, contemporaneous with high base level (Lake Titicaca), sediment load was sufficient to fill the valley and choke the river system. In embayments behind bedrock constrictions, sediments were deposited to heights in excess of 25 meters above the valley floor (T5). This aggradation was followed by downcutting of the T4 and T3 terraces. Initial downcutting began immediately after precipitation, runoff, and sediment load decreased and base level dropped. Downcutting was likely very rapid and was followed by a period of episodic equilibrium and minor downcutting that included a prolonged period of soil formation between ca

  20. Avalonian crustal controls on basin evolution: implications for the Mesozoic basins of the southern North Sea

    Science.gov (United States)

    Smit, Jeroen; van Wees, Jan-Diederik; Cloetingh, Sierd

    2015-04-01

    Little is known of the Southern North Sea Basin's (SNSB) Pre-Permian basement due to a lack of outcrop and cores. The nature and structure of the East Avalonian crust and lithosphere remain even less constrained in the absence of deep seismic (refraction) lines. However, various studies have hinted at the importance of the Reactivation of the Early Carboniferous fault network during each consecutive Mesozoic and Cenozoic tectonic phase, demonstrating the key role of weak zones from the Early Carboniferous structural grain in partitioning of structural deformation and vertical basin motions at various scales. Although the older basin history and the basement attract increasing attention, the Pre-Permian tectonics of the SNSB remains little studied with most attention focused on the Permian and younger history. The strong dispersal of existing constraints requires a comprehensive study from Denmark to the UK, i.e. the East Avalonian microplate, bordered by the Variscan Rheïc suture, the Atlantic and Baltica. Based on an extensive literature study and the reinterpretation of publicly available data, linking constraints from the crust and mantle to stratigraphic-sedimentological information, we complement the map of Early Carboniferous rifting of East Avalonia and propose a new tectonic scenario. From the reinterpretation of the boundary between Avalonia and Baltica we propose a new outline for the Avalonian microplate with implications for the tectonics of the North German Basin. Furthermore, we highlight the nature and extent of the major crustal/lithospheric domains with contrasting structural behaviour and the major boundaries that separate them. Results shed light on the effects of long lived differences in crustal fabric that are responsible for spatial heterogeneity in stress and strain magnitudes and zonations of fracturing, burial history and temperature history. The geomechanical control of large crustal-scale fault structures will provide the constraints

  1. Observations regarding the movement of barchan sand dunes in the Nazca to Tanaca area of southern Peru

    Science.gov (United States)

    Parker Gay, S.

    1999-03-01

    Significant studies of sand dunes and sand movement made in coastal southern Peru in 1959-1961 [Gay, S.P., 1962. Origen, distribución y movimiento de las arenas eólicas en el área de Yauca a Palpa. Boletin de la Sociedad Geologica del Perú 37, 37-58] have never been published in the English language and consequently have never been referred to in the standard literature. These studies contain valuable information, not developed by later workers in this field, that may be of broad general interest. For example, using airphotos of barchan dunes and plotting the rates of movement vs. dune widths, the author quantified the deduction of Bagnold [Bagnold, R.A., 1941. The Physics of Blown Sand and Desert Dunes. Methuen, London.] that the speed of barchan movement is inversely proportional to barchan size (as characterized by height or width). This led to the conclusion that all barchans in a given dune field, regardless of size, sweep out approximately equal areas in equal times. Another conclusion was that collisions between smaller, overtaking dunes and larger dunes in front of them do not result in destruction or absorption of the smaller dunes if the collision is a `sideswipe'. The dunes simply merge into a compound dune for a time, and the smaller dune then moves on intact, i.e., passes, the larger dune, whilst retaining its approximate original size and shape. Another result of the 1959-1961 studies was a map that documents the Pacific coast beaches as the source of the sand ( Fig. 1), which is then blown inland through extensive dune fields of barchans and other dune forms in great clockwise-sweeping paths, to its final resting place in huge sand masses, sometimes called `sand seas' [Lancaster, N., 1995. Geomorphology of Desert Dunes. Routledge, London], at higher elevations 20 to 60 km from the coast. A minor, but nevertheless interesting, discovery was a small heavy mineral dune located directly in the lee of a large barchan, evidently formed by the winnowing

  2. Structural Control of the Ubinas-Huaynaputina-Ticsani System: A Large, Young Silicic Magmatic System in Southern Peru

    Science.gov (United States)

    Lavallee, Y.; de Silva, S. L.; Salas, G.; Byrnes, J.

    2003-12-01

    The location of magma reservoirs and volcanic centers are commonly controlled by tectonic structures (e.g., Hutton, 1989; Gibbons and Moreno, 2002). In the Central Volcanic Zone, southern Peru, volcanism is mainly associated with the major NNW-SSE sinistral strike slip fault systems underlying the main volcanic arc. However, a group of related silicic volcanoes was recently discovered which crop out beyond the arc; the Ubinas-Huaynaputina-Ticsani system (UHTS). Characterizing its dimension and tectonic influences are crucial in order to evaluate corresponding volcanic hazards. Potentially active fault systems as well as major tectonic features in and around the UHTS were mapped and the structural framework was elucidated. The UHTS is located within a north to south extensional domain housing three fault systems: (1) the arc related NNW-SSE fault system, intersected by (2) a unique N-S en echelon strike slip fault system, and (3) a minor W-E fault system. Identification of confined Cretaceous volcanics known as the Matalaque formation indicated the presence of a narrow graben that developed on the western side of the N-S fault system. Interestingly all volcanic centers are positioned at the intersection of the NNW-SSE faults with the N-S faults. Seismic records revealed the concentration of seismicity around depths ranging between 20 and 33 km. The position of the UHTS is dictated by the intersection of the NNW-SSE and N-S major en echelon strike slip fault systems. We propose the role of the NNW-SSE fault as a deep pathway for magma ascent whereas the N-S strike-slip motion allowed the release of stress and deviation of magma, which scattered and ponded between adjacent NNW-SSE faults at ~30 km depths. Based on the vent distribution, we estimated the size of the silicic magma reservoir as approximately 40 x 60 km; this is a reasonable estimate since the withdrawal of a volume larger than 10 km3 was not significant enough to produce an equivalent caldera collapse

  3. Environmental evolution of the Rio Grande drainage basin and Nasca region (Peru) in 2003-2007 using ENVISAT ASAR and ASTER time series

    Science.gov (United States)

    Cigna, Francesca; Tapete, Deodato; Lasaponara, Rosa; Masini, Nicola

    2013-04-01

    Recent palaeo-environmental studies and remote sensing investigations demonstrated that the Rio Grande drainage basin in Southern Peru is a still evolving landscape, and impacts due to its changes have implications for the preservation of both the natural and cultural features of the Nasca region, well-known for the evidences of the ancient Paracas and Nasca Civilizations, who flourished from the 4th century BC to the 6th century AD. To image the modifications occurred in the last decade, we exploited the entire 4year-long stack of ENVISAT ASAR C-band archive imagery available over the region, which was provided by the European Space Agency (ESA) via the Cat-1 project 11073. The latter supports the activities of the Italian mission of heritage Conservation and Archaeogeophysics (ITACA), which directly involve researchers from the Institute for Archaeological and Monumental Heritage (IBAM) and the Institute of Methodologies for Environmental Analysis (IMAA), National Research Council (CNR) of Italy. With the aim of reconstructing the temporal evolution of the Rio Grande drainage basin and its effects and implications for the heritage of the region, we processed 8 ASAR Image Mode IS2 scenes acquired in descending mode between 04/02/2003 and 15/11/2005 and 5 images in ascending mode between 24/07/2005 and 11/11/2007, and focused on SAR backscattering information, amplitude change detection methods and extraction of ASAR-derived time series of the backscattering coefficient over target areas of interest. The ASAR 2003-2007 analysis was coupled and integrated with NDVI-based soil moisture and vegetation change assessment performed by using ASTER multi-spectral data acquired during the same time frame of the ASAR stacks, on 30/05/2003, 01/06/2004 and 10/06/2007. The research was performed both at the regional scale over the entire Rio Grande drainage basin, with particular focus on its tributaries Rio Ingenio, Rio Nazca and Rio Taruga, and at the local scale over the

  4. Glacial recession in the Tropical Andes from the Little Ice Age: the case of Ampato Volcanic Complex (Southern Peru

    Science.gov (United States)

    Alcalá, J.; Palacios, D.; Zamorano, J. J.

    2010-03-01

    Data published over the last decade reveal substantial glacial recession in the tropical Andes since the Little Ice Age (LIA), (Ramirez, et al., 2001; Rabatel, et al., 2005; Rabatel, et al., 2008; Vuille, et al., 2008; Hastenrath, 2009; Jomelli, et al., 2009), and a growing rate of recession since the 1980’s caused by global warming (Ramirez, et al., 2001; Vuille, et al., 2008). Today there is great interest in the evolution of these ice masses due to heightened awareness of climate change and of the strategic importance that glaciers have as a hydrologic resource for communities in arid climate zones in the tropical Andes (Mark, 2008; Vuille et al., 2008). Cordillera Blanca forms part of the Andes Mountains of northern Peru, and is a chosen site for many studies on glacier evolution. Vuille et al. 2008 determined that a considerable area of ice mass was lost at Huascarán-Chopicalqui glacier (18% from 1920-1970) and Astesonraju glacier (20% from 1962-2003). Studies at Coropuna volcano, which has the most extensive glacier field in the western range of southern Peru, also report a strong melting trend that began with only minimal recession from 1955-1986 (4%), but increased to 14% from 1986-2007 (Úbeda et al., 2009). Only a few of the Andes glaciers are consistently monitored, and the most comprehensive data are for Chacaltaya and Zongo glaciers (16º S) in Bolivia. Since the maximum LIA, Chacaltaya has lost 89% of its surface area, particularly in recent years. By 1983, the totaled loss was five times the shrinkage for the period 1940-1963 (Ramirez, et al., 2001). Zongo glacier maintained equilibrium from 1956-1975, but later experienced a period dominated by continuous recession (Soruco, et al., 2009). This study expands current knowledge of glacier evolution since the LIA in the Central Volcanic Zone (CVZ; 14º - 27º S) (Stern, 2004) of the Andes. The study site was chosen in an area that had never been used for preliminary research of this type, concretely

  5. Plate interactions control middle late Miocene, proto-Gulf and Basin and Range extension in the southern Basin and Range

    Science.gov (United States)

    Henry, Christopher D.; Aranda-Gomez, J. Jorge

    2000-03-01

    Middle-late Miocene (proto-Gulf; ˜12-6 Ma) extension around the Gulf of California (Gulf Extensional Province) is commonly interpreted as resulting from partitioning of oblique Pacific-North American plate motion into strike-slip displacement along the margin and east-northeast extension perpendicular to the margin within the North American plate. We propose that this mechanism also applies to kinematically similar, predominantly east-northeast extension that occurred at the same time throughout the southern Basin and Range province, from southern Arizona and New Mexico to the Trans-Mexican Volcanic Belt. New field and 40Ar/ 39Ar data in Sinaloa and Durango confirm that this episode of extension occurred on the mainland side of the Gulf and in the Basin and Range east of the Sierra Madre Occidental, which is generally considered the eastern margin of the Gulf Extensional Province. Published data indicate the middle-late Miocene episode also occurred across the northern and southern ends of the Sierra Madre where the Gulf Extensional Province connects with the Basin and Range: (1) from central Sonora into southern Arizona and New Mexico, and (2) from Nayarit into central Mexico north of the Trans-Mexican Volcanic Belt. This episode appears to have affected an area that continues to the eastern edge of the Basin and Range province in Texas and San Luis Potosi. Recognition that this episode of extension affected the entire southern Basin and Range resolves the discrepancy between the amount of extension calculated based on plate reconstructions and that based on field data within the Gulf Extensional Province alone. Published plate reconstructions require 160 to 110 km of east-northeast extension between ˜12 and 6 Ma. If taken up solely within the Gulf Extensional Province, this would have generated 66 to 78% extension, which is much greater than observed. Spread across the entire southern Basin and Range it requires only ˜20% total extension, which is more

  6. Factors influencing the productivity of irrigated crops in Southern Peru, in relation to prediction by simulation models

    NARCIS (Netherlands)

    Versteeg, M.N.

    1985-01-01

    The objective of the study was to determine the growth potential of alfalfa, potato, Rhodes grass and maize in the irrigated desert of S. Peru, as at that production level the highest utilization efficiency of irrigation water is usually obtained. Important growth- influencing factors were identifie

  7. My Classroom: Peru

    Science.gov (United States)

    Paglia, Deanna

    2015-01-01

    Angela Huanca Barrantes, a highly respected teacher of English as a foreign language (EFL) in the city of Ilo, has a strong impact on the lives of students at the Admirante Miguel Grau secondary school and at Centro Cultural Peruano Norteamericano, which is one of four binational centers in southern Peru. Due to Ms. Huanca's lack of understanding…

  8. A new structural model of the Pachitea Basin, Peru: Interaction of thick-skinned tectonics and salt detached thrusting

    Science.gov (United States)

    Witte, J.; Rebaza, J.; Westlund, D.; Stratton, M.; Alegria, C.

    2015-11-01

    We present four new structural transects, a new seismo-stratigraphic correlation, a refined structural model and new shortening rates for the Pachitea Basin (=PB), Peru. Our results are based on the integration and detailed interpretation of newly acquired industry seismic (2D, 2005 vintage), existing well data, existing and proprietary surface geology data and newly acquired aero magnetic data (2007 vintage). Our assessment confirms the presence of at least four distinct structural styles in the area, thick-skinned structures, thin-skinned detachment thrusting, salt-tectonics and localized strike-slip tectonics. Based on seismo-stratigraphic correlations we conclude that the oldest rocks carried to outcrop by the San Matias (=SM) thrust are of Jurassic age. We interpret the thin-skinned master detachment to be located in varying positions, directly below or above, autochtonous salt pillows. Timing assessment of the SM thrust sheet reveals that it has been active from at least ˜5 Ma to post-2 Ma, supporting regionally published timing data for this latitude. Positive topographic surface expressions indicate ongoing contraction along the mountain front of the Peruvian Eastern Cordillera (=EC). Across the PB we calculate between 2.6% and 5.5% for thick-skinned shortening and at least 25.5% for the thin-skinned shortening. For the SM thrust sheet we calculate a slip-rate of ˜1-1.6 mm/yr, which is in line with published slip rates on individual thrusts from around the world. Observations along the SM thrust system indicate that thin- and thick-skinned systems interact mechanically, and that they have been active intermittently. We conclude that the location of salt pillows as well as pre-existing or growing basement-involved structures helped trigger the SM thrust. Different types of salt bodies are present in the PB, autochtonous pillows, slightly thrusted pillows and allochtonous diapirs. Our results provide new insight into the structural interplay, particularly

  9. Modeling anomalous surface - wave propagation across the Southern Caspian basin

    Energy Technology Data Exchange (ETDEWEB)

    Priestly, K.F.; Patton, H.J.; Schultz, C.A.

    1998-01-09

    The crust of the south Caspian basin consists of 15-25 km of low velocity, highly attenuating sediment overlying high velocity crystalline crust. The Moho depth beneath the basin is about 30 km as compared to about 50 km in the surrounding region. Preliminary modeling of the phase velocity curves shows that this thick sediments of the south Caspian basin are also under-lain by a 30-35 km thick crystalline crust and not by typical oceanic crust. This analysis also suggest that if the effect of the over-pressuring of the sediments is to reduce Poissons` ratio, the over-pressured sediments observed to approximately 5 km do not persist to great depths. It has been shown since 1960`s that the south Caspian basin blocks the regional phase Lg. Intermediate frequency (0.02-0.04 Hz) fundamental mode Raleigh waves propagating across the basin are also severely attenuated, but the low frequency surface waves are largely unaffected. This attenuation is observed along the both east-to-west and west-to-east great circle paths across the basin, and therefore it cannot be related to a seismograph site effect. We have modeled the response of surface waves in an idealized rendition of the south Caspian basin model using a hybrid normal mode / 2-D finite difference approach. To gain insight into the features of the basin which cause the anomalous surface wave propagation, we have varied parameters of the basin model and computed synthetic record sections to compare with the observed seismograms. We varied the amount of mantel up-warp, the shape of the boundaries, the thickness and shear wave Q of the sediments and mantle, and the depth of the water layer. Of these parameters, the intermediate frequency surface waves are most severely affected by the sediments thickness and shear wave attenuation. fundamental mode Raleigh wave phase velocities measure for paths crossing the basin are extremely low.

  10. Origin of Meter-Size Granite Basins in the Southern Sierra Nevada, California

    Science.gov (United States)

    Moore, James G.; Gorden, Mary A.; Robinson, Joel E.; Moring, Barry C.

    2008-01-01

    Meter-size granite basins are found in a 180-km belt extending south from the South Fork of the Kings River to Lake Isabella on the west slope of the southern Sierra Nevada, California. Their origin has long been debated. A total of 1,033 basins have been inventoried at 221 sites. The basins occur on bedrock granitic outcrops at a median elevation of 1,950 m. Median basin diameter among 30 of the basin sites varies from 89 to 170 cm, median depth is 12 to 63 cm. Eighty percent of the basin sites also contain smaller bedrock mortars (~1-2 liters in capacity) of the type used by Native Americans (American Indians) to grind acorns. Features that suggest a manmade origin for the basins are: restricted size, shape, and elevation range; common association with Indian middens and grinding mortars; a south- and west-facing aspect; presence of differing shapes in distinct localities; and location in a food-rich belt with pleasant summer weather. Volcanic ash (erupted A.D. 1240+-60) in the bottom of several of the basins indicates that they were used shortly before ~760 years ago but not thereafter. Experiments suggest that campfires built on the granite will weaken the bedrock and expedite excavation of the basins. The primary use of the basins was apparently in preparing food, including acorns and pine nuts. The basins are among the largest and most permanent artifacts remaining from the California Indian civilization.

  11. Characteristics of seismostratigraphy and analysis of structurallithofacies in the southern Yellow Sea Cenozoic basin

    Institute of Scientific and Technical Information of China (English)

    ZHENGYanpeng; LIUChenguang; LIANGRuicai; LIUBaohua; WUJinlong

    2003-01-01

    In this paper,the upper structural layer of the southern Yellow Sea Basin (SYSB) is further divided into three layers based on the latest obtained high-resolution single-channel seismic profiles.Combined with the borehole data,the characteristics and evolvement of structure and environment since middle-late Tertiary are discussed.The study shows that the acoustic-base indicated by shallow seismic profiles represents the basic shape of the SYSB in late Oligocene-early Miocene.Based on the comprehensive analysis of some typical profiles crossing the basin about seismostratigraphy,gravity and magnetics,the basin about seismostratigraphy,gravity and magnetics,the basin edge fault and some basin inner structure are identified.Furthermore,the acoustic-base is classified into four types of basal lithofacies:Eogene basin basement,Paleozoic basement,Mesozoic basement and magma intrusion basement.

  12. Modification of Thickened Orogenic Crust by a Subducting Ridge: Disruption of the Andean Lower Crust of Southern Peru by the Subducting Aseismic Nazca Ridge

    Science.gov (United States)

    Bishop, B.; Beck, S. L.; Zandt, G.; Wagner, L. S.; Long, M. D.; Tavera, H.

    2015-12-01

    The subduction of oceanic plateaus or aseismic ridges represent significant perturbations to the long term development of subduction systems and associated orogenies, the consequences of which are variable and determined by the physical characteristics of both the overriding and subducting plates. Flat subduction of the ~18 km oceanic crust of the aseismic Nazca Ridge under the 50 km to 65 km continental crust of the Peruvian Andes provides an opportunity to investigate these consequences. Through analysis of 2233 teleseismic P-wave receiver functions from 55 broadband seismometers deployed in southern Peru for the PULSE, CAUGHT and PeruSE seismic experiments we have identified the South American continental Moho and subducted Nazca oceanic Moho to a higher degree of detail than previously possible in the region.We find that the continental Moho beneath the Western and Eastern Cordilleras of the Peruvian Andes is at a depth >60 km to the north and south of the subducted Nazca Ridge but at 500 km from the trench.

  13. MAPEO FOTOGRAMÉTRICO EN ARQUEOLOGÍA: EXPERIENCIAS DESDE EL PROYECTO RAMIS, CUENCA NORTE DEL TITICACA, PERÚ (Photogrammetric Mapping in Archaeology: Experiences from the Ramis Project, Northern Titicaca Basin, Peru

    Directory of Open Access Journals (Sweden)

    Luis A. Flores

    2015-10-01

    Full Text Available El registro arqueológico en tiempo real, desde el propio campo, se ha vuelto una práctica casi común para muchos arqueólogos. Aunque reemplazar el papel por la pantalla táctil aún sigue trayendo dudas y controversias. En este breve reporte queremos compartir una experiencia de registro usando un mapeo digital fotogramétrico en un sistema SIG, que fue practicado en la cuenca del Titicaca, una región altiplánica al sur del Perú, donde demostramos que este método de recolección de datos puede traer no solo rapidez sino también precisión en las mediciones. ENGLISH: The recording of archaeology in real-time, from the field itself, has become common practice for many archaeologists. Still, replacing paper with touch screens continues to raise doubts and cause controversies within the discipline. In this brief report, we want to share an experience recording in the field using digital photogrammetric mapping in GIS. This project was carried out in the Lake Titicaca Basin, a highland region in southern Peru, where we demonstrated that this method of recording data can not only bring faster, but more accurate measurements than older methods.

  14. New species of Solanum (Solanaceae) from Peru and Ecuador

    OpenAIRE

    Sandra Knapp

    2010-01-01

    Abstract Three new species of “non-spiny" Solanum are described from Peru and Ecuador, and a revised description for Solanum verecundum M. Nee is presented. Solanum kulliwaita S. Knapp, sp. nov. (Dulcamaroid clade) is endemic to the Department of Cuzco in southern Peru, and is most similar to the recently described Solanum sanchez-vegae S. Knapp of northern Peru. Solanum dillonii S. Knapp, sp. nov. (Brevantherum clade) is found in southern Ecuador and northern Peru in the Amotape-Huancabamba ...

  15. New insights into the mechanism of postseismic stress relaxation exemplified by the 23 June 2001 Mw = 8.4 earthquake in southern Peru

    Science.gov (United States)

    Hergert, Tobias; Heidbach, Oliver

    2006-01-01

    The 2001 Mw = 8.4 southern Peru subduction earthquake marked the beginning of a transient postseismic surface motion in direction of the coseismic displacement at the permanent GPS station Arequipa. In general this motion is assigned to afterslip. Our hypothesis is that the observed transient signal can be explained by stress relaxation processes in the overriding plate. We use a 2D finite element model incorporating non-linear viscoelastic Maxwell rheology. Our model results indicate that coseismically induced stresses are relieved by viscoelastic stress relaxation in the lower crust. The trenchward directed creep motion is transferred to the upper crust due to elastic coupling leading there to an instantaneous relief of elastic stresses. In contrast to the existing conceptual models for stress relaxation, which incorporate shear stresses, we conclude that tensional elastic stresses throughout the crust and upper mantle are the main driving forces for the transient GPS signal.

  16. Characteristics of seismostratigraphy and analysis of structural- lithofacies in the southern Yellow Sea Cenozoic basin

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper, the upper structural layer of the southern Yellow Sea Basin (SYSB) is further divided into three layers based on the latest obtained high-resolution single-channel seismic profiles. Combined with the borehole data, the characteristics and evolvement of structure and environment since middle-late Tertiary are discussed. The study shows that the acoustic-base indicated by shallow seismic profiles represents the basic shape of the SYSB in late Oligocene-early Miocene. Based on the comprehensive analysis of some typical profiles crossing the basin about seismostratigraphy, gravity and magnetics, the basin edge fault and some basin inner structure are identified. Furthermore, the acoustic-base is classified into four types of basal lithofacies: Eogene basin basement, Paleozoic basement, Mesozoic basement and magma intrusion basement.

  17. A see-saw of pre-Columbian boom regions in southern Peru, determined by large-scale circulation changes

    Science.gov (United States)

    Mächtle, B.; Schittek, K.; Forbriger, M.; Schäbitz, F.; Eitel, B.

    2012-04-01

    Environmental changes and cultural transitions during several periods of Peruvian history show a strong coincidence between humid and dry climatic oscillations and the rise and decline of cultures. It is noteworthy, that alternating periods of geo-ecological fragility and stability occurred in time and space between the coastal Nasca region (14.5° S) and the high Andean northern Titicaca basin, just a few hundred kilometers to the east. Based on a multi-proxy palynological and sedimentological approach to reconstruct palaeoenvironmental changes, we found that the Nasca region received a maximum of precipitation during the archaeological boom times of the Early Horizon and the Early Intermediate Period (800 BC - 650 AD, Paracas and Nasca cultures) as well as during the late intermediate period (1150-1450 AD), whereas, in contrast, the Titicaca region further to the south-east experienced drought and cultural depression during that times. During the Middle Horizon (650 - 1150 AD), the Tiwanaku agronomy and culture boomed in the Titicaca region and expanded to the west, contemporaneous with a raised lake level and more humid conditions. In the Nasca region, runoff for irrigation purposes was reduced and less reliable due to drought. Considering a coincidence between environmental and cultural changes, we state that success and decline of civilizations were controlled by hydrological oscillations, triggering fertility as well as a critical loss of natural resources. In response to spatial changing resources, cultural foci were shifted. Therefore, the success of pre-Columbian civilizations was closely coupled to areas of geo-ecological favorability, which were directly controlled by distinct regional impacts of large-scale circulation mechanisms, including El Niño - Southern Oscillation (ENSO). Changes in the position of the intertropical convergence zone (ITCZ) and the Bolivian anticyclone determined meridional shifts in moisture transport across the Andes, which

  18. On the actinopterygian fish fauna (Upper Cretaceous: Campanian) from the Kristianstad Basin, southern Sweden.

    OpenAIRE

    Bazzi, Mohamad

    2014-01-01

    Actinopterygian remains have been recovered from Upper Cretaceous (uppermost lower to lowermost upper Campanian) marine strata of the Kristianstad Basin, southern Sweden. This is the first record of Upper Cretaceous bony fish from the Fennoscandian shield. The fauna consists of higher taxa including Pachycormiformes (Pachycormidae), Elopiformes (Pachyrhizodontidae), Pycnodontiformes (Pycnodontidae), Aulopiformes (Enchodontidae), Ichthyodectiformes (Ichthyodectidae), and indeterminable teleost...

  19. Foraminiferal patterns in two trophically different regions: the northern Adriatic Sea and the southern Levantine Basin.

    NARCIS (Netherlands)

    Jannink, N.T.; Duijnstee, Ivo; van der Zwaan, Bert

    2001-01-01

    In spite of the fact that the northern Adriatic Sea and southern Levantine Basin are trophically quite different, the benthic foraminiferal standing stocks through the seasons were found to be in the same range. This suggests that the amount offood (organic matter) available at the sediment-water in

  20. The late Quaternary tephrostratigraphical record of the San Gregorio Magno basin (southern Italy)

    Science.gov (United States)

    Munno, R.; Petrosino, P.

    2007-03-01

    Twenty-one primary pyroclastic layers were found embedded in the lacustrine sediments of the San Gregorio Magno basin (Southern Apennines). These sand-sized layers were characterised by a noticeable juvenile fragments content and by a sharp basal contact with the underlying clay and silt sediments. The tephra layers have been correlated with terrestrial counterparts from well-known eruptive events of the Campanian volcanic area, or with reference layers from deep sea sediment cores and from the Monticchio maar sequence. The investigation of the San Gregorio Magno tephra layers made it possible to deduce that lacustrine sedimentation at San Gregorio Magno basin began before 170k yr BP and lasted at least until the emplacement of the Neapolitan Yellow Tuff, which occurred about 15k yr BP. The tephrochronology allowed determination of the varying sedimentation rate that occurred in the basin. Correlation of the lacustrine record with marine sequences has allowed development of a late Quaternary tephrostratotype for southern Italy. Copyright

  1. Focal mechanisms in the southern Dead Sea basin and related structural elements based on seismological data

    Science.gov (United States)

    Hofstetter, A.; Dorbath, C.; Dorbath, L.

    2014-12-01

    A dense temporary local seismological network was operated from 10/2006 to 3/2008 in the southern Dead Sea basin also outside the basin within the framework of the DESIRE (DEad Sea Integrated REsearch) project, providing many recordings of local earthquakes. We used the recordings of DESIRE and also the recordings of the permanent networks of Israel Seismic Network, Israel, and Jordan Seismic Observatory, Jordan. We determined high quality focal plane solutions of 490 events, using at least 6 stations (normally >10 stations) with a good station distribution around the epicenters. In the southern Dead Sea basin and adjacent regions there are several clusters of earthquakes. Most of the activity occurred along the eastern bordering fault of the basin, in the Lisan Peninsula and just south and north of it. Along the eastern and western bordering faults we observe mainly strike slip mechanism, probably supporting the left lateral motion along the Dead Sea fault. The nodal planes of many of focal mechanisms inside the basin are parallel to the transverse faults crossing the basin, i.e., Bokek and Ein-Gedi faults, and also parallel to faults that border the Lisan Peninsula on the north-western and south-western sides.

  2. Reconstruction of mass balance of Nevado Coropuna glaciers (Southern Peru) for Late Pleistocene, Little Ice Age and the present.

    Science.gov (United States)

    Ubeda, J.; Palacios, D.

    2009-04-01

    The Nevado Coropuna volcanic complex (15th 31'S-72 ° 39 ° W) is the quaternary stratovolcano northernmost of the central volcanic zone (CVZ) in the western flank of the Central Andes (Southern Peru). This consists in four adjacent volcanic buildings that are occupied over 5.100-5.700 masl by a system of glaciers covering an area of 47 Km2 in 2007 (Ubeda et al, 2008). The maximum expansion of glaciers during the Pleistocene affected an area of ~449 Km2, dropping to altitudes around 3.600-4800 m (Ubeda et al, 2007). In this work were mapped several hundreds of moraines which constitute a record of climate change since the last glacial maximum (LGM). Current glacier system is formed by dozen of glaciers descending slope down in all directions. Coropuna complex is an excellent laboratory for to investigate the control that climate change, tectonics and volcanism exert on the dynamics of glaciers, a scale of tens of years (by studying current glaciers) and also of tens of thousands of years (by analyzing the geomorphological evidence of its evolution in the past). Ubeda et al. (2008) analyzed the evolution of eighteen glaciers of Nevado Coropuna using indicators as surfaces and Equilibrium Line Altitudes (ELAs) of ice masses in 2007, 1986, 1955, Little the Ice Age (LIA) and Last Glacial Maximum (LGM). The glaciers were grouped into two sets: NE group (seven glaciers) and SE group (eleven glaciers). The work included statistical series of ELAs in each phase, estimates by Area x Altitud Balance Ratio (AABR) method, which was proposed by Osmaston (2005), in addition with estimates of timing (~17Cl36 Ka) and magnitude (~ 782-911 m) of ELA depression during LGM. The work included statistical series of ELAs in each phase, estimates by the method Area x Altitud Balance Ratio (AABR) proposed by Osmaston (2005), and in addition estimates of the timing (~17Cl36 Ka) and magnitude (~ 782-911 m) of ELA depression during LGM. The objective of this work is to estimate the current

  3. Imaging the transition from flat to normal subduction: variations in the structure of the Nazca slab and upper mantle under southern Peru and northwestern Bolivia

    Science.gov (United States)

    Scire, Alissa; Zandt, George; Beck, Susan; Long, Maureen; Wagner, Lara; Minaya, Estela; Tavera, Hernando

    2016-01-01

    Two arrays of broad-band seismic stations were deployed in the north central Andes between 8° and 21°S, the CAUGHT array over the normally subducting slab in northwestern Bolivia and southern Peru, and the PULSE array over the southern part of the Peruvian flat slab where the Nazca Ridge is subducting under South America. We apply finite frequency teleseismic P- and S-wave tomography to data from these arrays to investigate the subducting Nazca plate and the surrounding mantle in this region where the subduction angle changes from flat north of 14°S to normally dipping in the south. We present new constraints on the location and geometry of the Nazca slab under southern Peru and northwestern Bolivia from 95 to 660 km depth. Our tomographic images show that the Peruvian flat slab extends further inland than previously proposed along the projection of the Nazca Ridge. Once the slab re-steepens inboard of the flat slab region, the Nazca slab dips very steeply (˜70°) from about 150 km depth to 410 km depth. Below this the slab thickens and deforms in the mantle transition zone. We tentatively propose a ridge-parallel slab tear along the north edge of the Nazca Ridge between 130 and 350 km depth based on the offset between the slab anomaly north of the ridge and the location of the re-steepened Nazca slab inboard of the flat slab region, although additional work is needed to confirm the existence of this feature. The subslab mantle directly below the inboard projection of the Nazca Ridge is characterized by a prominent low-velocity anomaly. South of the Peruvian flat slab, fast anomalies are imaged in an area confined to the Eastern Cordillera and bounded to the east by well-resolved low-velocity anomalies. These low-velocity anomalies at depths greater than 100 km suggest that thick mantle lithosphere associated with underthrusting of cratonic crust from the east is not present. In northwestern Bolivia a vertically elongated fast anomaly under the Subandean Zone

  4. Geodetic measurement of deformation in the Ventura basin region, southern California

    Science.gov (United States)

    Donnellan, Andrea; Hager, Bradford H.; King, Robert W.; Herring, Thomas A.

    1993-01-01

    We have measured the deformation in the Ventura basin region, southern California, with Global Positioning System (GPS) measurements carried out over 4.6 years between 1987 and 1992. The deformation within our network is spatically variable on scales of tens of kilometers, with strain rates reaching 0.6 +/- 1 micro-rad/yr in the east-central basin. Blocklike rotations are observed south and northwest of the basin where the maximum shear strain rates are an order of magnitude lower (0.06 +/- 1 micro-rad/yr to the south). We also observed clockwise rotations of 1 deg - 7 deg/m.y. Shear strain rates determined by comparing angle changes from historical triangulation spanning several decades and GPS measurements give consistent, though less precise, results. The geodetic rates of shortening across the basin and Western Transverse Ranges are lower than those estimated from geological observations, but the patterns of deformation from the two methods agree qualitatively.

  5. Large lake basins of the southern High Plains: Ground-water control of their origin

    Energy Technology Data Exchange (ETDEWEB)

    Wood, W.W.; Sanford, W.E. (Geological Survey, Reston, VA (United States)); Reeves, C.C. Jr (Texas Tech. Univ., Lubbock (United States))

    1992-06-01

    The origin of the {approximately}40-50 topographically large lake basins on the southern High Plains of Texas and New Mexico has been an enigma. Previous workers have considered deflation or evaporite dissolution at depth and subsequent collapse as the most probable mechanisms. However, the eolian hypotheses have been unable to provide convincing arguments as to how the wind selectively erodes the thick, deflation-resistant calcrete 'caprock' that is persistent over much of the southern High Plains. Furthermore, recent detailed studies on some of the basins show no significant evaporite dissolution at depth, and neither mechanism offers a satisfactory explanation as to why the basins are almost universally associated with subsurface topographic highs, or why they are absent where the High Plains aquifer thickness exceeds 60 m. The authors address these latter concerns and modify the deflation hypothesis by proposing that the calcrete caprock may never have been deposited in the areas now occupied by the basins. The absence of calcrete deposition is proposed to have resulted from high water tables caused by an increase in hydraulic gradient where aquifers thinned above bedrock highs. A high water table close to an/or intersecting the surface prevents deposition of calcrete, and, thus, the uncemented surface would be more susceptible to deflation than the surrounding calcrete-covered areas after decline of the water table. The rise in water table associated with bedrock highs is documented by numerical simulation using boundary conditions and hydrologic parameters representative of the southern High Plains.

  6. Tectonic development of Laramide thrusts and basins in southern US Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Yin, A.; Ingersoll, R.V. (Univ. of California, Los Angeles, CA (United States). Dept. of Earth and Space Sciences)

    1993-04-01

    To elucidate the tectonic nature of the Laramide faults and basins and their role in controlling the development of late Cenozoic extensional structures, the authors compiled a tectonic map and constructed a series of E-W cross-sections between latitude 41[degree]N and latitude 32[degree]N along the Rockies. The tectonic map and balanced cross-sections show that the northern part of the southern Rockies is characterized by a W-directed thrust system and the southern part by an E-directed thrust system. The W- and E-directed systems overlap between 39[degree]N and 38[degree]N. On the surface, the transfer of shortening from the W-directed to the E-directed thrust system was accomplished by variation of displacements along strike of the two thrust systems. The authors hypothesize that the slip transfer at depth was accommodated along a commonly shared sub-horizontal detachment in the plastically deformed mid-crust, a situation similar to the recently documented basement-involved thrust systems in the South American Andes on the basis of focal-mechanism studies. The balanced cross-sections show that no systematic increase in shortening southward along strike of the southern Rockies can be detected within the resolution of the available surface and subsurface data. Dickinson and others (1988) classified three types of Laramide basins in the central Rockies on the basis of their structural settings: perimeter, ponded, and axial. Much debate has been centered on the origin of the axial basins that are characteristic of the southern Rockies. It is not clear whether they are the result of compressional tectonics, transpressional tectonics, or the superposition of the two in both time and space. An evolutionary model systematically accounts for the development of thrusts and basins during the Laramide orogeny and their influence on the development of younger normal faults and extensional basins during the late Cenozoic.

  7. Basin Analysis and Petroleum System Characterisation of Western Bredasdorp Basin, Southern Offshore of South Africa: Insights from a 3d Crust-Scale Basin Model - (Phase 1)

    Science.gov (United States)

    Sonibare, W. A.; Scheck-Wenderoth, M.; Sippel, J.; Mikeš, D.

    2012-04-01

    In recent years, construction of 3D geological models and their subsequent upscaling for reservoir simulation has become an important tool within the oil industry for managing hydrocarbon reservoirs and increasing recovery rate. Incorporating petroleum system elements (i.e. source, reservoir and trap) into these models is a relatively new concept that seems very promising to play/prospect risk assessment and reservoir characterisation alike. However, yet to be fully integrated into this multi-disciplinary modelling approach are the qualitative and quantitative impacts of crust-scale basin dynamics on the observed basin-fill architecture and geometries. The focus of this study i.e. Western Bredasdorp Basin constitutes the extreme western section of the larger Bredasdorp sub-basin, which is the westernmost depocentre of the four southern Africa offshore sub-basins (others being Pletmos, Gamtoos and Algoa). These basins, which appear to be initiated by volcanically influenced continental rifting and break-up related to passive margin evolution (during the Mid-Late Jurassic to latest Valanginian), remain previously unstudied for crust-scale basin margin evolution, and particularly in terms of relating deep crustal processes to depo-system reconstruction and petroleum system evolution. Seismic interpretation of 42 2D seismic-reflection profiles forms the basis for maps of 6 stratigraphic horizons which record the syn-rift to post-rift (i.e. early drift and late drift to present-day seafloor) successions. In addition to this established seismic markers, high quality seismic profiles have shown evidence for a pre-rift sequence (i.e. older than Late Jurassic >130 Ma). The first goal of this study is the construction of a 3D gravity-constrained, crust-scale basin model from integration of seismics, well data and cores. This basin model is constructed using GMS (in-house GFZ Geo-Modelling Software) while testing its consistency with the gravity field is performed using IGMAS

  8. Linkages Between Cretaceous Forearc and Retroarc Basin Development in Southern Tibet

    Science.gov (United States)

    Orme, D. A.; Laskowski, A. K.

    2015-12-01

    Integrated provenance and subsidence analysis of forearc and retroarc foreland basin strata were used to reconstruct the evolution of the southern margin of Eurasia during the Early to Late Cretaceous. The Cretaceous-Eocene Xigaze forearc basin, preserved along ~600 km of the southern Lhasa terrane, formed between the Gangdese magmatic arc and accretionary complex as subduction of Neo-Tethyan oceanic lithosphere accommodated the northward motion and subsequent collision of the Indian plate. Petrographic similarities between Xigaze forearc basin strata and Cretaceous-Eocene sedimentary rocks of the northern Lhasa terrane, interpreted as a retroarc foreland basin, were previously interpreted to record N-S trending river systems connecting the retro- and forearc regions during Cretaceous time. New sandstone petrographic and U-Pb detrital zircon provenance analysis of Xigaze forearc basin strata support this hypothesis. Qualitative and statistical provenance analysis using cumulative distribution functions and Kolmogorov-Smirnov (K-S) tests show that the forearc basin was derived from either the same source region as or recycled from the foreland basin. Quartz-rich sandstones with abundant carbonate sedimentary lithic grains and rounded, cobble limestone clasts suggests a more distal source than the proximal Gangdese arc. Therefore, we interpret that the northern Lhasa terrane was a significant source of Xigaze forearc detritus and track spatial and temporal variability in the connection between the retro- and forearc basin systems during the Late Cretaceous. A tectonic subsidence curve for the Xigaze forearc basin shows a steep and "kinked" shape similar to other ancient and active forearc basins. Initial subsidence was likely driven by thermal relaxation of the forearc ophiolite after emplacement while additional periods of rapid subsidence likely result from periods of high flux magmatism in the Gangdese arc and changes in plate convergence rate. Comparison of the

  9. Andean coastal uplift and active tectonics in southern Peru : Be-10 surface exposure dating of differentially uplifted marine terrace sequences (San Juan de Marcona, similar to 15.4 degrees S)

    OpenAIRE

    Saillard, Marianne; Hall, S. R; Audin, Laurence; Farber, D. L.; Regard, V.; Hérail, Gérard

    2011-01-01

    Along the San Juan de Marcona Bay of southern Peru, two spectacular sequences of preserved marine terraces record net Quaternary uplift. Previous geomorphic analysis of these paleo-shorelines has revealed evidence of upper plate deformation and regional uplift. However, in the absence of a robust absolute dating method, these studies contain substantial uncertainties concerning the numerical dating of these marine markers and thus the corresponding calculated surface uplift rates. However, fi...

  10. Reservoir-forming age and its exploration significance to stratigraphic reservoirs in southern Songliao Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Despite many studies concerning the forming age, evolution characteristics and the age of petroleum charging in the Fuxin upheaval of southern Songliao Basin, no consensus has been reached so far. This paper presents the first K-Ar dating of autogenetic illite from stratigraphic petroleum reservoirs in the Fuyu oil layer of the Fuxin upheaval belt. Isotopic test and age calculation were carried out based on the separation and purification of illite mineral, X-diffraction analysis and the detection of scanning electron microscopy. The evolution characteristics of structure, sedimentation, reservoir-forming about the Fuxin upheaval belt were interpreted in terms of the synthetical analysis of "six-type geological history" evolution in southern Songliao Basin. The geologic background of petroleum evolution and reservoir formation are similar in the entire central depression region of southern Songliao Basin. The Changling sag and the Fuxin upheaval belt brought about obvious upheaval-sag separation after the hydrocarbon-generation peak of K2qn1 and the main reservoir-forming period of the Fuyu oil layer, namely reservoir-forming happened before the Fuxin upheaval belt extensively raised. The reservoirs have three characteristics: the hydrocarbon source rock above the reservoir, the oil source in the locality, and the vertical migration. The geological cognition is corrected, that is, oil source came from the Changling sag and migrated from the side direction. The bulk process of petroleum charging in the stratigraphic hydrocarbon reservoirs in the Fuxin upheaval belt of southern Songliao Basin is determined according to the isotopic age of autogenetic illite in combination with the method of fluid inclusions. The cognition is helpful to exactly evaluate the resource potential and exploration direction in the Fuxin upheaval belt, Changling sag and their peripheral areas. The present results indicate that the combination of the two methods (the K-Ar dating of

  11. CLIMATE CHANGE IN NORTHERN AFRICA: TOWARDS A RETURN OF RAINFALL ON THE SOUTHERN MEDITERRANEAN BASIN

    OpenAIRE

    NOUACEUR ZEINEDDINE; Laignel, B.; TURKI IMEN; JEMAI HIBA

    2014-01-01

    To determine to what extent climate change affects the rainfall recorded on the southern Mediterranean basin, a trend analysis is proposed. This study is based on the chronological graphic method of processing information (MGCTI) of type "Matrice Bertin". Results show an extreme variability of the precipitations and a severe drought, especially for Morocco, observed since 1970s. Finally, a gradual return to humid conditions is observed from the beginning of the 2000s in Algeria and Tunisia an...

  12. Geothermal field and thermotectonic evolution in Southern South Yellow Sea Basin

    Institute of Scientific and Technical Information of China (English)

    YANG Shuchun; HU Shengbiao; CAI Dongsheng; FENG Xiaojie; GAO Le; LU Jingmei

    2003-01-01

    Based on the available borehole temperature data and measurements of thermal conductivities on 10 core samples in the Southern South Yellow Sea Basin, 8 heat flow values are obtained. The results show that the mean values of temperature gradient and heat flow are 28.6℃/km and 69 mW/m2, respectively. The thermal history reconstruction from the inversion of vitrinite reflectance data, using the temperature-gradient method, indicates that the highest paleo-heat flow occurred at the end of the Mesozoic, and then the basin began to cool to present day. Tectonic subsidence analysis shows that the basin experienced at least four episodes of quick subsidence since the late Paleozoic and that the tectonic evolution was quite strong and complex.

  13. Latest Miocene to Quaternary deformation in the southern Chaiwopu Basin, northern Chinese Tian Shan foreland

    Science.gov (United States)

    Lu, Honghua; Wang, Zhen; Zhang, Tianqi; Zhao, Junxiang; Zheng, Xiangmin; Li, Youli

    2015-12-01

    Basinward propagation of fold and thrust belts is a crucial geological process accommodating Cenozoic crustal shortening within the India-Eurasia collision zone. Anticlinal growth strata in the southern Chaiwopu Basin (a piggyback basin) of the northern Chinese Tian Shan foreland record basinward encroachment of the Tian Shan along the Junggar Frontal Thrust Fault. A new magnetostratigraphic section constrains the onset of syntectonic growth strata at circa 6.4 Ma and suggests synchronous basinward thrusting and propagation of the Tian Shan. The intense alluviation in the southern Chaiwopu Basin ceased at circa 0.55 Ma due to significant anticlinal growth and its resultant river incision. More recent anticlinal growth and deformation during the late Quaternary are revealed by folded river terraces developing across the anticline. The terrace height profile indicates that terrace T1H has been vertically offset about 0.6 m by thrust faulting since its formation at about 7 Ka. The stratigraphic and geomorphic data presented in this work are helpful to understand the initiation of thrust-related folding, as well as aggradation and subsequent incision, in foreland basins of the Tian Shan in relation to the India-Asia collision.

  14. The Mississippian Pedroches Basin: A failed attempt to propagate a Palaeotethys Arm across Southern Iberia?

    Science.gov (United States)

    Armendáriz, Maider; Quesada, Cecilio; Rosales, Idoia

    2013-04-01

    The Pedroches basin, straddling the boundary between the Ossa Morena (OMZ) and the Central Iberian (CIZ) zones of the Iberian Massif, forms one of the largest exposures of Mississippian rocks in the Iberian Peninsula. With the only exception of transitional facies near the northern and southern margins, the basin fill mostly consists of volcanic and sedimentary rocks deposited in relatively shallow continental shelf environments, in which storm activity was the main process of sediment supply and dispersal. Significantly, the Pedroches basin is split into several compartments (structural units), among which three syn-sedimentary, sigmoidal shape igneous belts, produced the most severe facies, structural and palaeogeographic changes. Owing to its timing of formation during the period of Variscan convergence, its location within an area undergoing active Variscan deformation, and the fact that the basin fill was itself affected by the Variscan orogeny, the Pedroches basin was considered a typical example of a syn-orogenic, peripheral foreland basin. Recent stratigraphical, sedimentological and isotope geology work has allowed a reinterpretation of the basin fill, in which two different sequences may be distinguished, with distinct tectono-stratigraphic significance. Above a basal conglomerate, the several hectometres thick lower part of the basin fill succession shows the highest variability among the various structural units in terms of lithology, facies and thickness. Most volcanic rocks are located within this lower part, within and in between the igneous belts, suggesting the important role of lithosphere-through, extension-related faulting in the origin of the basin. Significant across-strike thickness changes attest for syn-sedimentary horst and graben formation at this stage. On the contrary, the upper part of the basin fill is very similar in all units and corresponds to flyschoid greywacke-mudstone alternations (Culm facies). The change between the lower and

  15. A new species of Trachytherus (Notoungulata: Mesotheriidae) from the late Oligocene (Deseadan) of Southern Peru and the middle latitude diversification of early diverging mesotheriids.

    Science.gov (United States)

    Shockey, Bruce J; Billet, Guillaume; Salas-Gismondi, Rodolfo

    2016-01-01

    Herein we describe a new species of early diverging mesotheriid notoungulate from the late Oligocene of Moquegua, Peru. This taxon, Trachytherus ramirezi sp. nov., is distinctive in terms of a few characteristics that appear plesiomorphic as compared to those of other described mesotheriids, even other species referred to Trachytherus. Such plesiomorphic traits include the absence of an upper diastema and a lack of heart-shaped incisive foramina, traits that are generally present in other mesotheriids. Our phylogenetic analysis of described early divergent mesotheriids indicates that T. ramirezi was the earliest to diverge. This analysis also confirms the paraphyletic nature of the "genus" Trachytherus.          Geographically, T. ramirezi clusters among T. alloxus, T. subandinus, and T. spegazzinianus, all of which are known from a discrete region in the middle latitudes of western South America that we refer to as the Bolivian Orocline Region (BOR). Our palaeobiogeographic reconstruction using maximum parsimony identifies the BOR as a possible ancestral area for the Mesotheriidae and as an important region for their diversification. For the more exclusive Mesotheriinae, the BOR was reconstructed as the ancestral area, an area from which some mesotheriines would have later dispersed to southern South America. Uncertainty concerning the ancestral area, for the Mesotheriidae-which could be BOR or southern South America area (or both)-is possibly due to the ignorance of the phylogenetic affinities for the undescribed mesotheriid remains reported from Tinguirirican localities. The present description of T. ramirezi therefore adds to the high taxonomic diversity of early mesotheriid species in the relatively small area of the BOR and emphasizes the likely role played by this topographically dynamic area on mesotheriid evolution during a significant time in the history of the clade. PMID:27395103

  16. Geology, Water, and Wind in the Lower Helmand Basin, Southern Afghanistan

    Science.gov (United States)

    Whitney, John W.

    2006-01-01

    This report presents an overview of the geology, hydrology, and climate of the lower Helmand Basin, a large, closed, arid basin in southern Afghanistan. The basin is drained by the Helmand River, the only perennial desert stream between the Indus and Tigris-Euphrates Rivers. The Helmand River is the lifeblood of southern Afghanistan and has supported desert civilizations in the Sistan depression for over 6,000 years. The Helmand Basin is a structurally closed basin that began to form during the middle Tertiary as a consequence of the collision of several Gondwanaland fragments. Aeromagnetic studies indicate the basin is 3-5 kilometers deep over basement rocks. Continued subsidence along basin-bounding faults in Iran and Pakistan throughout the Neogene has formed the Sistan depression in the southwest corner of the basin. Lacustrine, eolian, and fluvial deposits are commonly exposed in the basin and were intruded by latest Miocene-middle Quaternary volcanoes, which indicates that depositional environments in the lower Helmand Basin have not substantially changed for nearly 10 million years. Lakes expanded in the Sistan depression during the Quaternary; however, the size and extent of these pluvial lakes are unknown. Climate conditions in the lower Helmand Basin likely mirrored climate changes in the Rajasthan Desert to the east and in Middle Eastern deserts to the west: greater aridity during global episodes of colder temperatures and increased available moisture during episodes of warmer temperatures. Eolian processes are unusually dominant in shaping the landscape in the basin. A strong wind blows for 120 days each summer, scouring dry lakebeds and creating dune fields from annual flood deposits. Nearly one-third of the basin is mantled with active or stabilized dunes. Blowing winds combined with summer temperatures over 50? Celsius and voluminous insect populations hatched from the deltaic wetlands create an environment referred to as the 'most odious place on

  17. Evidences for a Paleocene marine incursion in southern Amazonia (Madre de Dios Sub-Andean Zone, Peru)

    NARCIS (Netherlands)

    Louterbach, M.; Roddaz, M.; Bailleul, J.; Antoine, P.O.; Adnet, S.; Kim, J.H.; van Soelen, E.E.; Parra, F.; Gérard, J.; Calderon, Y.; Gagnaison, C.; Sinninghe Damsté, J.S.; Baby, P.

    2014-01-01

    This article presents new biostratigraphic dating, facies analysis, organic geochemical data and Nd–Sr isotopic provenance from five outcrops of southern Amazonia (MD-85, MD-177 MD-184, MD-255 and MD-256) to document for the first time the presence of a shallow marine ingression in the Paleocene of

  18. Evidences for a Paleocene marine incursion in southern Amazonia (Madre de Dios Sub-Andean Zone, Peru)

    NARCIS (Netherlands)

    Louterbach, M.; Roddaz, M.; Bailleul, J.; Antoine, P. O.; Adnet, S.; Kim, J. H.; van Soelen, E.; Parra, F.; Gérard, J.; Calderon, Y.; Gagnaison, C.; Sinninghe Damsté, J.S.; Baby, P.

    2014-01-01

    This article presents new biostratigraphic dating, facies analysis, organic geochemical data and Nd-Sr isotopic provenance from five outcrops of southern Amazonia (MD-85, MD-177 MD-184, MD-255 and MD-256) to document for the first time the presence of a shallow marine ingression in the Paleocene of

  19. The role of Argopecten purpuratus shells structuring the soft bottom community in shallow waters of southern Peru

    Science.gov (United States)

    Lomovasky, Betina J.; Gamero, Patricia A.; Romero, Leonardo; Firstater, Fausto N.; Gamarra Salazar, Alex; Hidalgo, Fernando; Tarazona, Juan; Iribarne, Oscar O.

    2015-12-01

    Accumulation of Argopecten purpuratus shells often occurs after El Niño events in shallow waters of Independencia Bay (14°17‧S-76°10‧W; Pisco, Peru). Here we experimentally investigate the effects of their shell accumulation on macrobenthos assemblages in soft bottom, shallow areas of the bay. A field experiment (from May 2006 to May 2007), including four treatments with different coverage levels of empty shells of A. purpuratus, were randomly arranged in: (1) areas devoid of shells ("Empty" treatment: experimental control), (2) 50% of the plot area covered with shells haphazardly distributed over the bottom ("medium" treatment), (3) 100% of the plot area covered with shells, forming a 10 cm valve layer ("full" treatment) and (4) "natural control". We found a total of 124 taxa throughout the experiment. Polychaetes, crustaceans and mollusks were the most abundant groups in "natural controls", dominated by the gastropod Nassarius gayi and the polychaetes Prionospio peruana, Platynereis bicanaliculata and Mediomastus branchiferus. The abundance of individuals (N) and the species richness (S) were higher in the "medium" treatment, but only in one month under positive sea bottom thermal anomalies. Similarity analysis (Bray-Curtis) showed that "natural control", "empty" and "full" treatments were more similar among them than the "medium" treatment. Multidimensional analysis showed no clear species association among treatments and a higher grouping among the samplings of Jun-06, Aug-06 and Nov-06. Our results also showed that the commercial crab Romaleon polyodon and the polyplacophora Tonicia elegans were positively affected by shell accumulations ("medium" treatment), while the limpet Fissurella crassa was negatively affected. Our study shows that directly by changing habitat structure or indirectly by changing sediment characteristics, the addition of scallop shells to the soft bottom can modify the macrobenthic assemblage; however, the seasonal oceanographic

  20. Submarine landslides in the Southern Adriatic basin: good candidates for potential paleoseismic analysis.

    Science.gov (United States)

    Dalla Valle, Giacomo; Trincardi, Fabio; Foglini, Federica; Campiani, Elisabetta; Pellegrini, Claudio

    2016-04-01

    The Plio-Pleistocene sedimentary succession of the western continental margin that surround the Southern Adriatic basin mainly consists of contourite depositional systems. The architectural stacking pattern of the contourites-linked bodies is sometimes interrupted by the presence of large-scale mass-transport complexes (MTCs). MTCs are spatially diffused along the margin and are characterized by high variability in size, morphology and geometries. In the northern sector of the margin MTCs derive from the remobilisation of upper-slope contourite drifts, whereas in the southern sector of the margin sedimentary instability involves shelf-margin, progradational deposits. The most prominent MTC of the northern sector of the margin is the Gondola Slide (GS) a large, deep-seated MTC composed of at least three distinct MTDs involving up to 40km3 of sediments. The events that have generated these MTDs have been enclosed within a robust chronological framework using sedimentary shallow piston-cores collected along the continental slope. The reconstruction of the age of these MTDs indicates that failures have repeatedly occurred along the margin during at least the last 55,000 years. Therefore, the GS case indicates that sediment instability processes can span a large portion of a sea-level cycle, pointing to triggering mechanisms that are independent from variations in the relative sea level position. The repeated GS failure events are therefore interpreted to be mainly triggered by earthquake shocks. The Southern Adriatic basin represents a seismically active area and earthquakes are generally cluster along long-lived shear zones. One of these zones, the Gondola Zone, which run across the shelf and the slope, close to the GS-MTC, has been site of paleoseismology analysis, indicating recent (younger than 5.5 kyr) tectonic deformation through E-W strike-slip faulting . Basin-scale MTDs characterize also the southern sector of the continental margin. MTDs are present both

  1. Basin Evolution of the Cretaceous-Early Eocene Xigaze Forearc, Southern Tibet

    Science.gov (United States)

    Orme, D. A.; Carrapa, B.; Kapp, P. A.; Gehrels, G. E.; Reiners, P. W.

    2013-12-01

    An understanding of the processes which control the evolution of forearc basins is important for deciphering the tectonic development of a convergent margin prior to continent-continent suturing. This study presents sedimentologic, modal petrographic and geo-thermochronologic data from the Xigaze forearc basin, preserved along ~ 600 km of the Indus-Yarlung Suture Zone in southern Tibet. From late Cretaceous to early Cenozoic time, subduction of Neo-Tethyan oceanic crust beneath the southern margin of Asia accommodated the northward motion of the Indian craton and formed the Xigaze forearc basin. Following collision with India in the early Cenozoic, the basin transitioned from predominantly marine to non-marine sedimentation and was subsequently uplifted to a mean elevation of 5000 m. Thus, the sedimentary record in the Xigaze forearc preserves information regarding the tectonic evolution of the Indo-Asia continental margin prior to and following collision. We present new measured sections and geo-thermochronologic data from Early Cretaceous to Early Eocene clastic and carbonate sedimentary rocks, preserved in two previously unexplored regions of the forearc, (1) at its western most extent, northwest of Saga, and (2) north of Lhatse. In turn, we compare our results with previously published data in order to synthesize our current understanding of forearc evolution. Strata preserved in the Lhaste region record an initial shallow marine phase of forearc sedimentation (Aptian), but quickly transition to deep marine slope and distal fan turbidite facies (Albian-Campanian). In contrast, facies preserved in the Saga region record a younger shoaling upward marine sequence (Maastrichtian-Ypresian), with the uppermost ~ 400 m consisting of fluvial channel sandstones and red-green paleosols. Facies and depositional environments in the Saga region are highly variable along strike, with turbidites, shelf limestones, estuarine siliciclastics and thick paleosols sequences all

  2. Seismic Structural Setting of Western Farallon Basin, Southern Gulf of California, Mexico.

    Science.gov (United States)

    Pinero-Lajas, D.; Gonzalez-Fernandez, A.; Lopez-Martinez, M.; Lonsdale, P.

    2007-05-01

    Data from a number of high resolution 2D multichannel seismic (MCS) lines were used to investigate the structure and stratigraphy of the western Farallon basin in the southern Gulf of California. A Generator-Injector air gun provided a clean seismic source shooting each 12 s at a velocity of 6 kts. Each signal was recorded during 6- 8 s, at a sampling interval of 1 ms, by a 600 m long digital streamer with 48 channels and a spacing of 12.5 m. The MCS system was installed aboard CICESE's (Centro de Investigacion Cientifica y de Educacion Superior de Ensenada) 28 m research vessel Francisco de Ulloa. MCS data were conventionally processed, to obtain post- stack time-migrated seismic sections. The MCS seismic sections show a very detailed image of the sub-bottom structure up to 2-3 s two-way travel time (aprox. 2 km). We present detailed images of faulting based on the high resolution and quality of these data. Our results show distributed faulting with many active and inactive faults. Our study also constrains the depth to basement near the southern Baja California eastern coast. The acoustic basement appears as a continuous feature in the western part of the study area and can be correlated with some granite outcrops located in the southern Gulf of California islands. To the East, near the center of the Farallon basin, the acoustic basement changes, it is more discontinuous, and the seismic sections show a number of diffracted waves.

  3. Clustering and interpretation of local earthquake tomography models in the southern Dead Sea basin

    Science.gov (United States)

    Bauer, Klaus; Braeuer, Benjamin

    2016-04-01

    The Dead Sea transform (DST) marks the boundary between the Arabian and the African plates. Ongoing left-lateral relative plate motion and strike-slip deformation started in the Early Miocene (20 MA) and produced a total shift of 107 km until presence. The Dead Sea basin (DSB) located in the central part of the DST is one of the largest pull-apart basins in the world. It was formed from step-over of different fault strands at a major segment boundary of the transform fault system. The basin development was accompanied by deposition of clastics and evaporites and subsequent salt diapirism. Ongoing deformation within the basin and activity of the boundary faults are indicated by increased seismicity. The internal architecture of the DSB and the crustal structure around the DST were subject of several large scientific projects carried out since 2000. Here we report on a local earthquake tomography study from the southern DSB. In 2006-2008, a dense seismic network consisting of 65 stations was operated for 18 months in the southern part of the DSB and surrounding regions. Altogether 530 well-constrained seismic events with 13,970 P- and 12,760 S-wave arrival times were used for a travel time inversion for Vp, Vp/Vs velocity structure and seismicity distribution. The work flow included 1D inversion, 2.5D and 3D tomography, and resolution analysis. We demonstrate a possible strategy how several tomographic models such as Vp, Vs and Vp/Vs can be integrated for a combined lithological interpretation. We analyzed the tomographic models derived by 2.5D inversion using neural network clustering techniques. The method allows us to identify major lithologies by their petrophysical signatures. Remapping the clusters into the subsurface reveals the distribution of basin sediments, prebasin sedimentary rocks, and crystalline basement. The DSB shows an asymmetric structure with thickness variation from 5 km in the west to 13 km in the east. Most importantly, a well-defined body

  4. Hydrological drought forecasting and skill assessment for the Limpopo river basin, Southern Africa

    Directory of Open Access Journals (Sweden)

    P. Trambauer

    2014-08-01

    Full Text Available Ensemble hydrological predictions are normally obtained by forcing hydrological models with ensembles of atmospheric forecasts produced by Numerical weather prediction models. To be of practical value to water users, such forecasts should not only be sufficiently skilful, they should also provide information that is relevant to the decisions end users make. The semi-arid Limpopo basin in Southern Africa has experienced severe droughts in the past, resulting in crop failures, high economic losses and the need for humanitarian aid. In this paper we address the seasonal prediction of hydrological drought for the Limpopo river basin by testing three proposed forecasting systems (FS that can provide operational guidance to dam operators and water managers within the basin at the seasonal time scale. All three FS include a distributed hydrological model of the basin, and are forced with either (i a global atmospheric model forecast (ECMWF seasonal forecast system – S4, (ii the commonly applied Ensemble Streamflow Prediction approach (ESP using resampled historical data, or (iii a conditional ESP approach (ESPcond, which is conditional on the ENSO signal. We determine the skill of the three systems in predicting drought indices and streamflow. We also assess the skill of the model in predicting indicators that are meaningful to the local end users in the basin. FS_S4 shows moderate skill for all lead times (3, 4, and 5 months and aggregation periods. FS_ESP also performs better than climatology for the shorter lead times, but with a lower skill than FS_S4. FS_ESPcond shows skill in between the other two FS, though its skill is shown to be more robust. The skills of FS_ESP and FS_ESPcond reduce rapidly with increasing lead time. Both FS_S4 and FS_ESPcond show good potential for seasonal hydrological drought forecasting in the Limpopo river basin, which is encouraging in the context of providing better operational guidance to water users.

  5. Multi-Layer Superposed Coalbed Methane System in Southern Qinshui Basin, Shanxi Province, China

    Institute of Scientific and Technical Information of China (English)

    Zheng Zhang; Yong Qin; Xuehai Fu; Zhaobiao Yang; Chen Guo

    2015-01-01

    Multi-coalbed developed in Carboniferous–Permian coal-bearing strata of southern Qinshui Basin, and different coal-bearing segments have different coalbed methane (CBM) reservoiring characteristics. Analysis of previous studies suggests that the essence of an unattached CBM system is to possess a unified fluid pressure system, which includes four key elements, namely, gas-bearing coal-rock mass, formation fluid, independent hydrodynamic system and capping layer condition. Based on the exploration and exploitation data of CBM, it is discovered that the gas content of coal seams in southern Qinshui Basin presents a change rule of non-monotonic function with the seam dipping, and a turning point of the change appears nearby coal seam No. 9, and coal seams of the upper and the lower belong to different CBM systems respectively; well test reservoir pressure shows that the gradient of coal seam No. 15 of the Taiyuan Formation is significantly higher than that of coal seam No. 3 of the Shanxi Formation; the equivalent reservoir pressure gradient of coal seam No. 15 “jumps” obviously compared with the reservoir pressure gradient of coal seam No. 3 in the same vertical well, that is, the relation between reservoir pressure and burial depth takes on a characteristic of nonlinearity; mean-while, the vertical hydraulic connection among the aquifers of Shanxi Formation and Taiyuan Forma-tion is weak, constituting several relatively independent fluid pressure systems. The characteristics dis-cussed above reveal that the main coal seams of southern Qinshui Basin respectively belong to relatively independent CBM systems, the formation of which are jointly controlled by sedimentary, hydrogeolog-ical and structural conditions.

  6. Structural development and crustal stretching in the Muglad Basin, southern Sudan

    Science.gov (United States)

    Mohamed, A. Y.; Ashcroft, W. A.; Whiteman, A. J.

    2001-02-01

    A simplified model cross-section has been established from integrated well data, reflection seismic and gravity data along a northeast-southwest profile in the Unity-Kaikang area in the Muglad Basin, southern Sudan. A multi-layer crustal model has been created to produce a better estimate of the crustal extension involved and assess some of the key factors in the basin's formation by comparison to a theoretical model. Within the sedimentary section, three reflection seismic horizons were picked and their depths were calculated: Top Bentiu (Cenomanian), Top Abu Gabra (Aptian-Albian) and Top Basement (Late Jurassic-Early Cretaceous). The integrated well and seismic data indicate a sedimentary section up to 11 km thick along the cross-section. Different densities were assigned to the three sedimentary layers according to well data, and upper and lower crustal layers were incorporated in the model. Isostatic compensation of the sedimentary fill and the resultant crustal thinning was estimated by gravity modelling. The stretching of the lithosphere is estimated at ≈56 km (≈61%), corresponding to a β factor of 1.61. The form of the basin agrees with the model of a rift basin developed over an extended period of time.

  7. Recent trends in annual snowline variations in the northern wet outer tropics: case studies from southern Cordillera Blanca, Peru

    Science.gov (United States)

    Veettil, Bijeesh Kozhikkodan; Wang, Shanshan; Bremer, Ulisses Franz; de Souza, Sergio Florêncio; Simões, Jefferson Cardia

    2016-03-01

    This paper describes the changes in the annual maximum snowlines of a selected set of mountain glaciers at the southern end of the Cordillera Blanca between 1984 and 2015 using satellite images. Furthermore, we analysed the existing glacier records in the Cordillera Blanca since the last glacial maximum to understand the evolution of glaciers in this region over a few centuries. There was a rise in the snowline altitude of glaciers in this region since the late 1990s with a few small glacier advances. Historical to the present El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) records were also analysed to understand whether there was a teleconnection between the glacier fluctuations in the region and the phase changes of ENSO and PDO. We also assessed the variations in three important climatic parameters that influence the glacier retreat—temperature, precipitation, and relative humidity—over a few decades. We calculated the anomalies as well as the seasonal changes in these variables since the mid-twentieth century. There was an increase in temperature during this period, and the decrease in precipitation was not so prominent compared with the temperature rise. There was an exceptionally higher increase in relative humidity since the early 2000s, which is relatively higher than that expected due to the observed rate of warming, and this increase in humidity is believed to be the reason behind the unprecedented rise in the snowline altitudes since the beginning of the twenty-first century.

  8. Tephrochronological study in the quaternary Val d'Agri intermontane basin (Southern Apennines, Italy)

    Science.gov (United States)

    Zembo, Irene; Vignola, Pietro; Andò, Sergio; Bersezio, Riccardo; Vezzoli, Luigina

    2011-01-01

    In the south-eastern depocentre of the Val d'Agri basin (Southern Apennines), a volcanic ash layer crops out interbedded within poorly structured alluvial fan deposits of Late Pleistocene age. Textural, depositional and pedological features of this weathered layer suggest a primary deposition from a pyroclastic fall-out of volcanic ash. Chemical analyses of feldspars show an alkali trachytic composition and accessory minerals association allow to correlate this tephra layer with the regionally dispersed Y-7 marine tephra layer (Tufo Verde Epomeo eruption, Ischia volcano), dated at 56 ± 4 ka. The Val d'Agri tephra here described for the first time was deposited during MIS Stage 3. Its recovery and characterization permit to contribute to regional correlation of the Mediterranean climatic and volcanic events from marine to continental successions and to describe landscape evolution of the Southern Apennines during glacial-interglacial cycles.

  9. Diamondoid Hydrocarbons as Maturity Indicators for Condensates from Southern Indus Basin, Pakistan

    OpenAIRE

    Shagufta Nasir; Tahira Fazeelat

    2013-01-01

    Diamondoid hydrocarbons have been examined in condensates reservoired in the Southern Indus Basin using GC-MS. Bulk properties reveal that samples are waxy and low sulfur with the exception of Pakhro and Gopang which are nonwaxy. TIC show bimodal distribution of n-alkanes along with high abundance of C20+ n-alkanes indicating substantial contribution of terrigeneous OM in these samples. CPI close to one is consistent with mature nature of oils. The samples show two ranges of Pr/Ph ratios. Tho...

  10. CLIMATE CHANGE IN NORTHERN AFRICA: TOWARDS A RETURN OF RAINFALL ON THE SOUTHERN MEDITERRANEAN BASIN

    Directory of Open Access Journals (Sweden)

    NOUACEUR ZEINEDDINE

    2014-03-01

    Full Text Available To determine to what extent climate change affects the rainfall recorded on the southern Mediterranean basin, a trend analysis is proposed. This study is based on the chronological graphic method of processing information (MGCTI of type "Matrice Bertin". Results show an extreme variability of the precipitations and a severe drought, especially for Morocco, observed since 1970s. Finally, a gradual return to humid conditions is observed from the beginning of the 2000s in Algeria and Tunisia and since 2008 in Morocco. This new trend is also confirmed by recent results provided by agricultural data of 2011/2012 and 2012/2013.

  11. Tectonic and climatic control on geomorphological and sedimentary evolution of the Mercure basin, southern Apennines, Italy

    Science.gov (United States)

    Robustelli, Gaetano; Ermolli, Elda Russo; Petrosino, Paola; Jicha, Brian; Sardella, Raffaele; Donato, Paola

    2014-06-01

    The morpho-tectonic and sedimentary evolution of the Mercure intramontane basin (Calabria-Lucania boundary, southern Apennines) has been assessed through facies analysis, morphostratigraphy and geomorphological correlation with adjacent areas. The Mercure basin, one of the most active seismogenic zones of the southern Apennines, is a favorable area for reconstructing the main stages of landscape evolution of the axial zone because of its capability to record changes in base level during the Quaternary. In addition, the presence of both erosional and depositional Palaeosurfaces is a useful marker for reconstructing tectonic and morphogenetic events, and hence to detect the role played by tectonics and climate in its genesis, evolution and extinction. The present study identifies the key role of tectonics and denudation, combined with high-frequency floods, as mechanisms controlling alluvial sedimentation in the study area. During endorheic conditions, denudational processes driven by pulses of extensional deformation of the basin margin caused strong alluvial inputs that resulted in the development of alluvial fans. Alluvial facies are mainly characterized by turbulent, subaerial, hyperconcentrated flood flows deposited during the glacial, semi-arid conditions of MIS 14. The retrogradational stacking pattern of the alluvial system indicates decreasing rates of tectonic activity along with declining river gradients. The Mercure coalescing alluvial fans were inundated by lake transgression during MIS 13 in response to (i) abrupt tectonic subsidence at the basin margins and (ii) large decrease of coarse sediment supply due to the interplay among climate, tectonics and catchment size changes. In this regard, it is suggested that tectonic control on the drainage network along with climate and long-term slope evolution may have caused marked pulses in sediment supply, thus influencing the arrangement of facies associations in the sedimentary succession. In addition, the

  12. Contribution to the diversity and conservation knowledge of mammals in the basin of the Apurimac river, Peru

    Directory of Open Access Journals (Sweden)

    Víctor Pacheco

    2013-04-01

    Full Text Available The present work documents the diversity of mammals in the headwaters of the Apurímac river, one of the most important information gaps in Peru, based on an evaluation of fi ve sampling areas in the departments of Apurímac (Cconoc, Velavelayoc, Ayacucho (Yanamonte, Ccentabamba and Cuzco (Catarata. Capture’s effort was 1280 trap-nights and 41 mistnet-nights. Sixty species were recorded in the study area and included 15 threatened species and four species endemic to Perú. As expected, bats and rodents were the most diverse orders (66,7 %. The species diversity in the sites sampled declines signifi cantly with elevation from the lowest elevation sites (Ccentabamba and Catarata to the highest (Velavelayoc. The marsupial Monodelphis peruviana and the Dwarf Brocket deer Mazama chunyi are fifi rst records for the department of Ayacucho. The bats Artibeus planirostris and Myotis keaysi, and the river otter Lontra longicaudis are fifi rst records for the department of Apurímac. For bats, the relative abundance showed a signifi cant negative correlation with elevation, but was not signifi cant for small terrestrial mammals. The species of Sturnira, Akodon and Thomasomys had the highest values of relative abundance. The diversity indices (Shannon-Wiener and Simpson also showed also a signifi cant negative correlation with elevation. The Apurímac river headwater is estimated to have at least 97 mammals species. We recommend creating conservation areas in Huanipaca, Yanamonte and Catarata, and enlarging the area of the Santuario Histórico Machu Picchu to include the archaeological site of Choquequirao.

  13. Physicochemical, microbiological and toxicological quality of raw milk in cattle basins of the region Puno-Peru

    OpenAIRE

    Magaly Brousett-Minaya; Ana Torres Jiménez; Alex Chambi Rodríguez; Bethy Mamani Villalba; Hernán Gutiérrez Samata

    2015-01-01

    The objective of this study was to evaluate the quality of raw milk in seven representative basins of the region Puno. The results were compared with the standards established by the International Standard for milk and milk products NTP 200.001-2003 and the Official Mexican Standard NOM-155-SCFI-2012 for the parameters of protein and lactose in the absence of Peruvian parameters. For physicochemical characterization pH, acidity, density, fat, protein, lactose, total solids, fat solids was det...

  14. Physicochemical, microbiological and toxicological quality of raw milk in cattle basins of the region Puno-Peru

    Directory of Open Access Journals (Sweden)

    Magaly Brousett-Minaya

    2015-10-01

    Full Text Available The objective of this study was to evaluate the quality of raw milk in seven representative basins of the region Puno. The results were compared with the standards established by the International Standard for milk and milk products NTP 200.001-2003 and the Official Mexican Standard NOM-155-SCFI-2012 for the parameters of protein and lactose in the absence of Peruvian parameters. For physicochemical characterization pH, acidity, density, fat, protein, lactose, total solids, fat solids was determined microbiological analysis of E. coli and mesophilic, just as we also performed the study spanned pesticide residue analysis such as organochlorines, organophosphates, carbamates and pyrethroids with sensitivity 1.0ug / g sample which gave negative results for the four groups of pesticides, the physicochemical determinations over 50% of the basins (except for pH and acidity is found within the standards of the NTP and NOM. The presence of mesophilic were mostly found within the parameters except for two milksheds and as for E. Coli any basin met established standards found one poor quality milk hygienic.

  15. Spatial ecology of blue shark and shortfin mako in southern Peru: local abundance, habitat preferences and implications for conservation

    DEFF Research Database (Denmark)

    Adams, Grant D.; Flores, Daniel; Flores, Oscar Galindo;

    2016-01-01

    While global declines of pelagic shark populations have been recognized for several years, conservation efforts remain hampered by a poor understanding of the spatial distribution and ecology. Two species of conservation concern are the blue shark Prionace glauca and the shortfin mako shark Isurus...... as a function of environmental variables including the El Niño Southern Oscillation (ENSO). A 10-year data series revealed declining annual landings since 2011, despite no changes in management structures. Significant aggregations of both species were found in the southwestern part of Peruvian waters (74–76°W......; 17–19°S) with both locations targeted by major fishing efforts. P. glauca CPUE increased during La Niña conditions, and CPUE of both species declined when water depths exceeded 1000 m. Correlations with lunar illumination and chlorophyll-a were revealed in P. glauca and I. oxyrinchus, respectively...

  16. Impacts of satellite-based precipitation datasets on rainfall-runoff modeling of the Western Amazon basin of Peru and Ecuador

    Science.gov (United States)

    Zubieta, Ricardo; Getirana, Augusto; Espinoza, Jhan Carlo; Lavado, Waldo

    2015-09-01

    Satellites are an alternative source of rainfall data used as input to hydrological models in poorly gauged or ungauged regions. They are also useful in regions with highly heterogeneous precipitation, such as the tropical Andes. This paper evaluates three satellite precipitation datasets (TMPA, CMORPH, PERSIANN), as well as a dataset based only on rain gauge data (HYBAM), and their impacts on the water balance of the Western Amazon basin, a region where hydrological modeling and hydrological forecasting are poorly developed. These datasets were used as inputs in the MGB-IPH hydrological model to simulate streamflows for the 2003-2009 period. The impacts of precipitation on model parameterization and outputs were evaluated in two calibration experiments. In Experiment 1, parameter sets were separately defined for each catchment; in Experiment 2, a single parameter set was defined for the entire basin. TMPA shows overestimated precipitation over the northern region, while CMORPH and PERSIANN significantly underestimate rainfall in the same that region and along the Andes. TMPA and CMORPH lead to similar estimates of mean evapotranspiration (∼2 mm/day) for different regions along the entire basin, while PERSIANN is the least accurate (∼0.5 mm/day). Overall, better scores for streamflow simulations are obtained with Experiment 1 forced by HYBAM and TMPA. Nevertheless, results using the three satellite datasets indicate inter-basin differences, low performance in the northern and high in the southern regions. Low model performances are mainly related to scale issues and forcing errors in small basins over regions that present very low rainfall seasonality.

  17. A numerical method for determining the state of stress using focal mechanisms of earthquake populations: application to Tibetan teleseisms and microseismicity of Southern Peru

    Science.gov (United States)

    Carey-Gailhardis, Evelyne; Louis Mercier, Jacques

    1987-03-01

    give a good evaluation of the regional (mean) state of stress. Focal mechanisms of the small events are also modelled by a mean stress deviator, but this differs significantly from the regional state of stress in southern Peru deduced from Quaternary faulting. This may be due to imprecise location of the small events. However, some movements are strongly different from those predicted by the computed mean stress deviator. This suggests that small fault kinematics surely depend on the regional state of stress but that local effects may control the small deformations.

  18. Traveling Weather Disturbances in Mars' Southern Extratropics: Sway of the Great Impact Basins

    Science.gov (United States)

    Hollingsworth, Jeffery L.

    2016-04-01

    ' transient barotropic/baroclinic eddies are significantly influenced by the great impact basins of this hemisphere (e.g., Argyre and Hellas). In addition, the occurrence of a southern storm zone in late winter and early spring is keyed particularly to the western hemisphere via orographic influences arising from the Tharsis highlands, and the Argyre and Hellas impact basins. Geographically localized transient-wave activity diagnostics are constructed that illuminate fundamental differences amongst such simulations and these are described.

  19. Stratigraphic correlations of the Vaca Muerta formation in the southern Neuquén basin, Argentina

    Science.gov (United States)

    Nesma, Krim; Patrice, Imbert; Cedric, Bonnel; Charles, Aubourg

    2013-04-01

    The petroleum Neuquén basin, south west Argentina, contains a continuous late Triassic to Cenozoic succession including continental and marine sediments, deposited under a variety of tectonic regimes. The Vaca Muerta formation is one of the major source rocks of the Neuquén basin and was deposited during the Andic cycle. This formation consists of organic-rich dark brown to black shales and mudstones deposited during a major transgression, in euxinic conditions on a shelf and slope during the Tithonian. Over most of the basin, the Vaca Muerta formation overlies the continental deposits of the Tordillo formation. The contact between the two formations is isochronous throughout the basin and marks the Tithonian transgression (Leanza, 1981). After this transgression, prograding bodies were deposited and the Vaca Muerta corresponds to the distal part of this latest. It includes stages from Middle Tithonian in the south to Valanginian in the north (Leanza & Hugo, 1977). The Vaca Muerta formation is well exposed in the southern part of the Neuquén basin, from the Picun Leufu Anticline to the north of the town of Las Lajas. It corresponds in these two areas to a succession of dark to brown shales and carbonate beds. In details, we can divide it into two parts: the Lower Vaca Muerta and the Upper Vaca Muerta. Above, the Picun Leufu formation overlies the Vaca Muerta formation and consists of carbonaceous and siliciclastics prograditional bodies. This unit is absent in the "North Zapala Zone" and its lateral equivalent is less carbonaceous. In this poster; we propose eight detailed sedimentological logs, which are correlated along 120 km north-south trend (from the Picun Leufu Anticline to the south west to the Agrio thrust Belt (ATB) to the north). This correlation will be used to assess the vertical and lateral variability of the Vaca Muerta deposits and to define the palaeogeographic evolution of that region. This allowed us to identify two major prograding sequences

  20. Seismicity and focal mechanisms for the southern Great Basin of Nevada and California: 1987 through 1989

    Energy Technology Data Exchange (ETDEWEB)

    Harmsen, S.C.; Bufe, C.G.

    1991-12-31

    For the calendar year 1987, the southern Great basin seismic network (SGBSN) recorded about 820 earthquakes in the southern Great Basin (SGB). Local magnitudes ranged from 0.2 to 4.2 (December 30, 1987, 22:50:42 UTC at Hot Creek Valley). Five earthquakes epicenters in 1987 within the detection threshold of the seismic network are at Yucca Mountain, the site of a potential national, high-level nuclear waste repository. The maximum magnitude of those five earthquakes is 1.1, and their estimated depths of focus ranged from 3.1 to 7.6 km below sea level. For the calendar year 1988, about 1280 SGB earthquakes were catalogued, with maximum magnitude-4.4 for an Owens Valley, California, earthquake on July 5, 1988. Eight earthquake epicenters in 1988 are at Yucca Mountain, with depths ranging from three to 12 km below sea level, and maximum magnitude 2.1. For the calendar year 1989, about 1190 SGB earthquakes were located and catalogued, with maximum magnitude equal to 3.5 for earthquake about ten miles north of Las Vegas, Nevada, on January 9. No Yucca Mountain earthquakes were recorded in 1989. An earthquake having a well-constrained depth of about 30 km below sea level was observed on August 21, 1989, in eastern Nevada Test Site (NTS).

  1. Reservoir Potential of Silurian Carbonate Mud Mounds in the Southern Sichuan Basin, Central China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wenzhi; YANG Xiaoping; Steve KERSHAW; ZHANG Baomin

    2006-01-01

    Lower Silurian mud mounds of the Shinuilan Formation, located in the southern Sichuan Basin, China, have developed in open shelf settings in deeper water than shallow-water reef-bearing limestones that occur in the region. An integration of the outcrop, drill data and seismic profiles show that contemporaneous faults have controlled the boundary and distribution of the sedimentary facies of Lower Silurian rocks in the southern Sichuan Basin. Mounds appear to have developed in the topographic lows formed by synsedimentary faulting, on the shelf of the Yangtze Platform. Average mound thickness is 20 m, maximum 35 m. Mounds are composed mainly of micrite, possibly microbially bound, and are overlain by shales. Mound tops are preferentially dolomitized, with the Mg2+ source probably from the clay content of the mound-top carbonate. Microfacies analysis and reconstruction of the diagenetic history reveal that the mound tops have higher porosity, and are gas targets; in contrast, mound cores and limbs show pores filled by three generations of calcite cement, and therefore have a low gas potential.

  2. Rates of soil development from four soil chronosequences in the southern Great Basin

    Science.gov (United States)

    Harden, J.W.; Taylor, E.M.; Hill, C.; Mark, R.K.; McFadden, L.D.; Reheis, M.C.; Sowers, J.M.; Wells, S.G.

    1991-01-01

    Four soil chronosequences in the southern Great Basin were examined in order to study and quantify soil development during the Quaternary. Soils of all four areas are developed in gravelly alluvial fans in semiarid climates with 8 to 40 cm mean annual precipitation. Lithologies of alluvium are granite-gneiss at Silver Lake, granite and basalt at Cima Volcanic Field, limestone at Kyle Canyon, and siliceous volcanic rocks at Fortymile Wash. Ages of the soils are approximated from several radiometric and experimental techniques, and rates are assessed using a conservative mathematical approach. Average rates for Holocene soils at Silver Lake are about 10 times higher than for Pleistocene soils at Kyle Canyon and Fortymile Wash, based on limited age control. Holocene soils in all four areas appear to develop at similar rates, and Pleistocene soils at Kyle Canyon and Fortymile Wash may differ by only a factor of 2 to 4. Over time spans of several millennia, a preferred model for the age curves is not linear but may be exponential or parabolic, in which rates decrease with increasing age. These preliminary results imply that the geographical variation in rates within the southern Great Basin-Mojave region may be much less significant than temporal variation in rates of soil development. The reasons for temporal variation in rates and processes of soil development are complexly linked to climatic change and related changes in water and dust, erosional history, and internally driven chemical and physical processes. ?? 1991.

  3. Post-partum reproductive efficiency of pure- and cross-bred Zebu cattle under different management and nutritional conditions in the Amazon Basin of Peru

    International Nuclear Information System (INIS)

    The experiments described were carried out by the Research Centre of the Veterinary Institute for Tropical and High Altitude Research (IVITA), at an experimental station located near Pucallpa in the Amazon Basin of Peru. The aim was to study some of the factors affecting reproductive efficiency under field conditions, with special emphasis on the effects of nutrition, body weight, suckling and some adaptation related parameters in pure- and cross-bred Zebu cattle. Progesterone assay was used in combination with clinical examinations to evaluate more precisely the reproductive parameters studied. A long post-partum anoestrus interval was the most important factor limiting reproductive efficiency in pure-bred Zebu animals. The 10 month interval observed under field and experimental conditions was shortened by improving the level of nutrition. However, the first ovulation after parturition was inhibited by free or restricted suckling until weaning took place 8 months post-partum. In contrast, dual purpose cross bred Bos taurus x Bos indicus animals tended to show better reproductive performance when suckling was allowed, the difference being significant when adequate management and feeding were also provided. Body weight at calving and subsequent weight changes during the post-partum period significantly affected the onset of post-partum reproductive function in both pure- and cross-bred Zebu cows. Cross-bred animals with a low body weight at calving remained acyclic for 8 months. On small farms, only 35% of the intervals between artificial insemination services were in the range of 18 to 24 days. Progesterone profiles determined between successive oestrous periods revealed a high frequency of unobserved oestrus. The correlation between rectal palpation of ovarian structures and progesterone concentration was 0.82 and 0.96 in diagnosing luteal and non-luteal structures respectively. The combination of weekly clinical examinations and progesterone determinations gave a

  4. Emerged quaternary marine terraces in southern Peru: Sea level changes and continental margin tectonics over the subducting Nazca Ridge

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, J.T.J.

    1988-01-01

    Because of the arid climate, mollusk shells in the marine cover strata are exceptionally well preserved and provide datable samples for a terrace and sea level chronology. Amino acid racemization was the most extensively used dating method, with three other numerical dating methods, electron spin resonance (ESR), Uranium-series, and radiocarbon ages used to calibrate the amino acid ages. D-alloisoleucine/L-isoleucine (A/I) ratios of >200 mollusks shells belong to six statistically and geomorphically defined aminozones. Aminozone IIa correlates with the last Interglacial (deep-sea oxygen isotope Stage 5e) based on 12 ESR ages and the similarity of the IIa ratios to those determined from calibrated last Interglacial sites on the Pacific Coast, U.S. Calibrated amino acid ages for the other aminozones are; I = >45,000 yr B.P. and {le} 87,000; IIb = 211,000 yr B.P.; III = 297,000 yr B.P.; IV = 496,000 yr B.P.; and V {ge} 945,000 yr B.P. The calibrated ages agree with ESR, Uranium series, and radioactive ages. The pattern of terrace deformation can be approximated by a simple geometric model in which the subconducting Nazca Ridge migrates obliquely southeastward as a rigid trapezoid beneath the forearc. The model correctly predicts a pattern of marine terrace deformation with the highest elevations located above the southern flank of the Nazca Ridge and subsidence above the northern flank. The topography, pattern of marine terrace deformation, and Quaternary rates of uplift of the Paracas Block are determined by oblique subduction of the aseismic Nazca Ridge.

  5. Soil erosion vulnerability in the verde river basin, southern minas gerais

    Directory of Open Access Journals (Sweden)

    Vinícius Augusto de Oliveira

    2014-06-01

    Full Text Available Soil erosion is one of the most significant environmental degradation processes. Mapping and assessment of soil erosion vulnerability is an important tool for planning and management of the natural resources. The objective of the present study was to apply the Revised Universal Soil Loss Equation (RUSLE using GIS tools to the Verde River Basin (VRB, southern Minas Gerais, in order to assess soil erosion vulnerability. A annual rainfall erosivity map was derived from the geographical model adjusted for Southeastern Brazil, calculating an annual value for each pixel. The maps of soil erodibility (K, topographic factor (LS, and use and management of soils (C were developed from soils and their uses map and the digital elevation model (DEM developed for the basin. In a GIS environment, the layers of the factors were combined to create the soil erosion vulnerability map according to RUSLE. The results showed that, in general, the soils of the VRB present a very high vulnerability to water erosion, with 58.68% of soil losses classified as "High" and "Extremely High" classes. In the headwater region of VRB, the predominant classes were "Very High" and "Extremely High" where there is predominance of Cambisols associated with extensive pastures. Furthermore, the integration of RUSLE/GIS showed an efficient tool for spatial characterization of soil erosion vulnerability in this important basin of the Minas Gerais state.

  6. Earthquake location data for the southern Great Basin of Nevada and California: 1984 through 1986

    International Nuclear Information System (INIS)

    This report presents data in map and table form for earthquake parameters such as hypocentral coordinates and magnitudes for earthquakes located by the southern Great Basin Seismic network for the time period January 1, 1984, through December 31, 1986. These maps show concentrations of earthquakes in regions previously noted to be seismically active, including the Pahranagat Shear Zone, Pahroc Mountains, southern Nevada Test Site, Timber Mountain, Black Mountain, Gold Mountain, Montezuma Range, and Grapevine Mountains. A concentration of earthquake activity in the Reveille Range was observed in 1986, in a previously inactive area. The northern Nevada Test Site had fewer earthquakes than a comparable area of the southern Nevada Test Site, indicating that the low-yield nuclear testing program is not currently triggering significant numbers of aftershocks. Eight microearthquakes occurred at Yucca Mountain during the 1984-1986 monitoring period. Depths of focus for well-located earthquakes continue to indicate a bimodal distribution, with peaks at 1 to 2 and 8 to 9 km below sea-level and a local minimum at 4 to 5 km. Focal mechanisms range from strike slip to normal slip. No dependence of slip mode on depth or magnitude is evident. 8 refs., 46 figs., 5 tabs

  7. Comparative analysis of post-breakup basin evolution along the South-American and South-African margins, southern Atlantic

    Science.gov (United States)

    Strozyk, F.; Back, S.; Kukla, P. A.

    2012-04-01

    Recently, considerable attempts have been made to compare the sedimentary basin evolution and the associated tectonic framework on both sides of the South-Atlantic. However, yet there are still unresolved questions concerning the tectono-sedimentary styles of margin basin evolution that markedly differ from north to south. Amongst the most striking observations is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic margin segment on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. Adding to the heterogeneity of the system, the northernmost segment of the South Atlantic rift and salt basins is also characterized by a pronounced asymmetry, with the Brazilian margin now comprising narrower and deeper rift basins with less salt than the Congo-Gabon conjugate margin. This project deals with a large-scale comparison of this very different post-breakup tectono-stratigraphic development of the southern and northern South American and African continental margins that both record thick post-rift sedimentary successions. To gain detail of the basin margin evolution, we focus on a regional comparison between the post-breakup records archived in the large offshore southern Brazil basins (Pelotas, Santos, Campos) and the post-breakup continental margin successions of offshore Namibia (e.g. Orange Basin) and southern Angola (e.g. Kwanza Basin). A tectonic-stratigraphic comparison of representative geological transects provides a comprehensive basin-to-basin documentation of key factors influencing margin development which include the subsidence development through time, the sediment (in-)flux and storage patterns and the respective type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems). Data from the salt-prone areas offshore South America and southern

  8. Back-arc basin opening and closure along the southern margin of the Sea of Japan

    Science.gov (United States)

    Sato, Hiroshi; Claringbould, Johan; Ishiyama, Tatsuya; Kato, Naoko; Abe, Susumu; Kawasaki, Shinji

    2016-04-01

    Following the tsunami disaster produced by 2001 Off-Tohoku earthquake (M9) along the Pacific coast of Japan, the Japanese government started an intense evaluation of tsunami hazards. This evaluation spanned along the full Japanese coast, including the Sea of Japan coast on the western side of the Japan arc. In the Sea of Japan, tsunamis are produced by crustal faults. As the longer interval of faulting activity, the historical records of tsunamis in the Sea of Japan are not enough for the evaluation of tsunami height. Thus, the evaluation is carried out based on structural analyses of the margin of the Sea of Japan. To get better understanding of the present-day structural geometry and develop a source-fault model in this region, intense seismic reflection profiling has been carried out since 2013. We introduce the results of the seismic reflection profiles and discuss the structural evolution of the southern margin of the Sea of Japan. 2D seismic reflection profiles were acquired using 1950 cu. in. air-gun and 2100 m streamer cable. The seismic profiles provide the image image up to 3 seconds TWT. The southern margin of the Sea of Japan was produced by back-arc opening and post-rift deformation, and the structural evolution of this area is divided into several stages: rifting (25 - 14 Ma), post-rift compression (14 - 5 Ma), weak thrusting (5 - 1 Ma), and strike-slip deformation (1 Ma to present). During the rifting stage that is associated with the fan-shaped opening of the Sea of Japan, grabens and half-grabens were formed trending parallel to the extension of SW-Japan arc. These grabens were filled by syn-rift sediments, and the maximum thickness of basin fill is observed along the southern margin of the rifted crust. The opening of the Sea of Japan ceased as a result of the collision of Izu-Bonin-Mariana arc system at the Izu collision zone on the central part of Honshu, Japan. Soon after the this event, the young Shikoku basin within the Philippine Sea plate

  9. Detailed history of atmospheric trace elements from the Quelccaya ice core (Southern Peru) during the last 1200 years

    Science.gov (United States)

    Uglietti, C.; Gabrielli, P.; Thompson, L. G.

    2013-12-01

    The recent increase in trace element concentrations, for example Cr, Cu, Zn, Ag, Pb, Bi, and U, in polar snow and ice has provided compelling evidence of a hemispheric change in atmospheric composition since the nineteenth century. This change has been concomitant with the expansion of the Industrial Revolution and points towards an anthropogenic source of trace elements in the atmosphere. There are very few low latitude trace element ice core records and these are believed to be sensitive to perturbations of regional significance. To date, these records have not been used to document a preindustrial anthropogenic impact on atmospheric composition at low latitudes. Ice cores retrieved from the tropical Andes are particularly interesting because they have the potential to reveal detailed information about the evolution and environmental consequences of mineral exploitation related to the Pre Inca Civilizations, the Inca Empire (1438-1533 AD) and the subsequent Spanish invasion and dominance (1532-1833 AD). The chemical record preserved in the ice of the Quelccaya ice cap (southern Peruvian Andes) offers the exceptional opportunity to geochemically constrain the composition of the tropical atmosphere at high resolution over the last ~1200 years. Quantification of twenty trace elements (Ag, Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, Rb, Sb, Sn, Ti, Tl, U, V, and Zn) was performed by ICP-SFMS over 105 m of the Quelccaya North Dome core (5600 m asl, 128.57 m) by analyzing 2450 samples. This provides the first atmospheric trace element record in South America spanning continuously and at high resolution for the time period between 1990 and 790 AD. Ag, As, Bi, Cd, Cr, Co, Cu, Mn, Mo, Sb, Sn, Pb and Zn show increases in concentration and crustal enrichment factor starting at different times between 1450 and 1550 AD, in concomitance with the expansions of the Inca Empire and, subsequently, the Spanish Empire well before the inception of the Industrial Revolution. This

  10. Spotlight: Peru.

    Science.gov (United States)

    Yacher, L

    1985-09-01

    This article highlights population statistics from Peru, the 3rd largest country in Latin America. The population in 1985 has been estimated at 19.7 million. In 1982, the birth rate was 35/1000 and the mortality rate was 10/1000. Infant mortality stood at 99/1000 live births and life expectancy at birth was 59 years. 41% of Peru's population is under 15 years of age, and only 4% is 65 years of age or older. The country's total fertility rate is 5.2 births/woman. Only 0.4% of the population is foreign born. Peru is highly urbanized, and 65% of the country's total population growth in 1981 occurred in its cities. 1 in 3 Peruvians resides in the capital city of Lima. The 2 largest racial groups are mestizos and whites (53%) and Indians (46%). 21% of the population is illiterate. 40.7% of the labor force is employed in agriculture; however, only 15% of the national income is derived from agriculture. The GNP per capita was US$1040 in 1983. The country's economy is in serious trouble at present, with an annual inflation rate of 250% and a foreign debt of US$13.5 billion. PMID:12340368

  11. Simulation of the Arid Climate of the Southern Great Basin Using a Regional Climate Model.

    Science.gov (United States)

    Giorgi, Filippo; Bates, Gary T.; Nieman, Steven J.

    1992-11-01

    As part of the development effort of a regional climate model (RCM)for the southern Great Basin, this paper present savalidation analysis of the climatology generated by a high-resolution RCM driven by observations. The RCM is aversion of the National Center for atmospheric Research-Pennsylvania State University mesoscale model, version 4 (MM4), modified for application to regional climate simulation. Two multiyear simulations, for the periods 1 January 1982 to 31 December 1983 and 1 January 1988 to 25 April 1989, were performed over the western United States with the RCM driven by European Centre for Medium-Range Weather Forecasts analyses of observations. The model resolution is 60 km. This validation analysis is the first phase of a project to produce simulations of future climate scenarios over a region surrounding Yucca Mountain, Nevada, the only location currently being considered as a potential high-level nuclear-waste repository site.Model-produced surface air temperatures and precipitation were compared with observations from five southern Nevada stations located in the vicinity of Yucca Mountain. The seasonal cycles of temperature and precipitation were simulated well. Monthly and seasonal temperature biases were generally negative and largely explained by differences in elevation between the observing stations and the model topography. The model-simulated precipitation captured the extreme dryness of the Great Basin. Average yearly precipitation was generally within 30% of observed and the range of monthly precipitation amounts was the same as in the observations. Precipitation biases were mostly negative in the summer and positive in the winter. The number of simulated daily precipitation events for various precipitation intervals was within factors of 1.5-3.5 of observed. Overall, the model tended to overestimate the number of light precipitation events and underestimate the number of heavy precipitation events. At Yucca Mountain, simulated

  12. Chronological dating and tectonic implications of late Cenozoic volcanic rocks and lacustrine sequence in Oiyug Basin of southern Tibet

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Reconstruction of uplift history of the Tibetan Plateau is crucial for understanding its environmental impacts. The Oiyug Basin in southern Tibet contains multiple periods of sedimentary sequences and volcanic rocks that span much of the Cenozoic and has great potential for further studying this issue. However, these strata were poorly dated. This paper presents a chronological study of the 145 m thick and horizontally-distributed lacustrine sequence using paleomagnetic method as well as a K-Ar dating of the underlying volcanic rocks. Based on these dating results, a chronostratigraphic framework and the basin-developmental history have been established for the past 15 Ma, during which three tectonic stages are identified. The period of 15-8.1 Ma is characterized by intense volcanic activities involving at least three major eruptions. Subsequently, the basin came into a tectonically quiescent period and a lacustrine sedimentary sequence was developed. Around 2.5 Ma, an N-S fault occurred across the southern margin of the basin, leading to the disappearance of the lake environment and the development of the Oiyug River. The Gyirong basin on northern slope of the Himalayas shows a similar basin developmental history and thus there is a good agreement in tectonic activities between the Himalayan and Gangdise orogenic belts. Therefore, the tectonic evolution stages experienced by the Oiyug Basin during the past 15 Ma could have a regional significance for southern Tibet. The chronological data obtained from this study may provide some constraints for further studies with regard to the tectonic processes and environmental changes in southern Tibetan Plateau.

  13. Petroleum geology and exploration potential of Ucayali Basin, Peru%秘鲁Ucayali盆地油气地质特征及勘探潜力分析

    Institute of Scientific and Technical Information of China (English)

    王青; 王建君; 汪平; 朱志强; 赵旭

    2012-01-01

    The Ucayali Basin is one of the sub-Andean foreland basins with several types of pays. There are two sets of main source rocks including the Pucara Formation (T-J) and the Ene Formation ( P). Multiple sets of reservoirs generated, such as the Chonta, Vivian, Cushabatay, Agua Caliente and Raya Formations of Cretaceous and the Ene Formation of Permian. And the seal factors for the reservoirs are excellent. There are two types of thrust deformations in the Ucayali Basin. Basement-involved structures mainly occur in the north, while thin-skinned thrusting structures exist in the south. Traps of the discovered fields in the basin are mainly anticlines related to thrust faults. In the Northern Ucayali sub-Basin, hydrocarbons from the Pucara Formation move through unconformities and faults towards Cretaceous formations, and re-accumulate after the Quechua tectonic movement. However, in the Southern Ucayali sub-Basin, natural gas generate from the over mature shales of the Ene Formation, and migrate into the Permian and Cretaceous reservoirs. Four types of exploration leads exist in the basin; traps in thrustfold-foredeep belt, Carbonate reservoir in the Pucara Formation, gas prospects of Permian in the northern basin, and Cretaceous stratigraphic traps in the east of the basin.%秘鲁Ucayali盆地是位于安第斯山山前的前陆盆地之一,盆地内发育多套储盖组合.盆地内主力烃源岩包括上三叠统一下侏罗统Pucara组和二叠系Ene组的泥岩;发育多套储层,包括白垩系Chonta,Vivian,Cushabatay,AguaCaliente和Raya组储层,以及下二叠统的Ene组砂岩层等;盖层条件良好.北部主要发育基底相关的逆冲断层,而在盆地的南部发育薄皮式的逆冲断层,盆地内已发现的油气田的圈闭类型主要是与逆冲断层相关的断背斜圈闭.北Ucayali次盆Pucara组生成的油气运移至该组地层的剥蚀面,充注至白垩系,但遭到后期造山运动的破坏,通过再次运移聚集成藏.

  14. Reconstruction of Equilibrium Line Altitudes of Nevado Coropuna Glaciers (Southern Peru) from the Late Pleistocene to the present

    Science.gov (United States)

    Úbeda, J.; Palacios, D.; Vázquez, L.

    2009-04-01

    The Nevado Coropuna (15°31'S-72°39'W) is a volcanic complex located 200 km NE of the city of Arequipa, in the Southern Peruvian Andes. The summit area in the complex is covered with a glacier system formed by dozens of branches descending in all directions totaling many km2 in surface area. The study of the volcanic complex and its glaciers is of great interest because it is the main water reserve for tens of thousands of people, because of the risk scenario created by the presence of ice masses on a volcano with relatively recent activity, and because it constitutes an excellent geoindicator of the effects of climate change on ice masses in the western mountain chain of the Central Andes. This research aims to analyze glacier evolution using as geoindicators variations in glacier surface and equilibrium line altitudes (ELAs), defining deglaciation rates based on those variations and preparing forecasts with them on when the ice masses might disappear if the same rates were to occur in the future. In addition, a first estimation is attempted of the chronologies of the last phase of volcanic activity and the last phase of maximum glacier advance that can be attributed to the Late Glacial or Last Glacial Maximum periods. To achieve these aims, digital topography with 50m contour interval, two orthophotos of the central section of the Coropuna complex (15-6-1955 and 21-10-1986), an ASTER satellite image (12-11-2007) and geomorphological mapping of the volcanic complex created in a previous phase of the research (Ubeda, 2007) were integrated into a Geographical Information System (GIS). The GIS was used to determine the global extent of the glacier system, and in more detail, that of two groups (NE and SE) in 1955, 1986 and 2007. Using the geomorphological cartography as a basis, the extent of the glaciers during their last advance in the Little Ice Age (LIA) and their last maximum advance were calculated. Next, surface areas for all phases were calculated using

  15. Large lake basins of the southern High Plains: ground-water control of their origin?

    Science.gov (United States)

    Wood, W.W.; Sanford, W.E.; Reeves, C.C., Jr.

    1992-01-01

    We modify the deflation hypothesis by proposing that the calcrete caprock may never have been deposited in the areas now occupied by the basins. The absence of calcrete deposition is proposed to have resulted from high water tables caused by an increase in hydraulic gradient where aquifers thinned above bedrock highs. A high water table close to and/or intersecting the surface prevents deposition of calcrete, and thus, the uncemented surface would be more susceptible to deflation than the surrounding calcrete-covered areas after decline of the water table. The rise in water table associated with bedrock highs is documented by numerical simulation using boundary conditions and hydrologic parameters representative of the southern High Plains. -from Authors

  16. Human environment and climate during the Middle Pleistocene in southern Italy (Boiano basin, Molise)

    Science.gov (United States)

    Orain, R.; Lebreton, V.; Russo Ermolli, E.; Sémah, A.-M.; Nomade, S.; Shao, Q.; Bahain, J.-J.; Peretto, C.

    2012-04-01

    Palaeobotanical investigations undertaken on early prehistoric sites of Western Europe, as Pont-de-Lavaud (France, ca 1.2 - 1 Ma) and Ca' Belvedere di Monte Poggiolo (Italy, ca 1.2 - 0.8 Ma), indicate that hominins have settled in different types of environments. During the "Mid-Pleistocene Transition (MPT)", at about 1 to 0.6 Ma, the transition from 41-ka to 100-ka dominant climatic oscillations occurring within a long-term cooling trend is associated with an aridity crisis and strongly modified the structure of environments. Since the MPT, the specific climate and environment evolution of the southern Italy provided propitious conditions for a long-term human occupation even during glacial times and the density of prehistoric sites could probably be explained by the amount of sustainable environments. The human strategy of occupation of a territory probably was motivated by availabilities of resources for subsistence in the local ecosystems. Sites such as La Pineta (ca 600 ka), Notarchirico (ca 600 ka), San Nicola di Monteroduni (ca 400 ka) or Ceprano (ca 350 ka) testify to the preferential occupation of the valleys of the central and southern Apennines during this period. In this area, the Boiano basin (Molise, Italy) recorded a lacustrine and fluvio-palustrine sedimentation, with basal deposits older than 440 ka deduced from tephrochronology. Pollen analyse of the Boiano sequence aims to describe the evolution of vegetation and climates between OIS 13 and 9, at regional and micro-regional scales. The characteristics of the Boiano basin are enlightened within the progressive reduction of the deciduous forest diversity along the Middle Pleistocene. The main palaeoecological information consists of an important persistence of edaphic humidity during the glacial phases. The peculiar conditions recorded in the region could have constituted a refuge for arboreal flora during the Middle Pleistocene and provided subsistence resources to the animal and human communities.

  17. Strengthening Adaptation to Extreme Climate Events in Southwestern Amazonia: an Example from the Trinational Acre River Basin in the Madre de Dios/Peru - Acre/Brazil - Pando/Bolivia (MAP) Region.

    Science.gov (United States)

    Brown, I. F.

    2015-12-01

    Southwestern Amazonia, where Bolivia, Brazil and Peru meet, faces numerous challenges to the sustainable utilization of land and water resources as the region experiences rapid population and economic growth, expanding agriculture, transportation and energy sectors, along with frequent flooding and droughts. It is also predicted to be one of the most susceptible areas for climate change in the coming decade. The Acre River Basin, one of the few trinational basins in Amazonia, lies at the center of the Madre de Dios Region (Peru), Acre State (Brazil) and Pando Department (Bolivia) or MAP Region. It covers approximately 7,500 km2 and its inhabitants range from indigenous groups avoiding contact with industrial society to more than 60,000 dwellers of a binational urban center. The basin incorporates most the challenges facing the region and this paper discusses steps underway to address the basin's vulnerability to climate-related threats. A trinational group of professionals used GIS databases and local knowledge to classify these threats and possible societal responses. To prioritize threats and to propose responses, this group adapted a method proposed by the Queensland Climate Change Centre of Excellence of Australia to develop climate risk matrices for assessing impacts, adaptation, risk and vulnerability. The three priority climate variables were prolonged and more frequent droughts, more intense flooding, and more days with temperatures > 35oC. The final matrix proposed two areas of concentration - 1) Reduce the vulnerability of communities to hydro-meteorological extreme events and 2) Protect and restore ecosystems that maintain critical water-related resources with actions in public policy, capacity-building, and immediate activities. These results are being incorporated into the Amazon Project of the Global Environment Fund of the United Nations Environment Program, administered by the Amazon Cooperation Treaty Organization (ACTO).

  18. Ar/39Ar age spectrum analysis of detrital microclines from the southern San Joaquin Basin, California

    International Nuclear Information System (INIS)

    Detrital microcline grains from sedimentary strata preserve a record of thermal evolution in the temperature range approx.= 1000 to 2000C which can be revealed by 40Ar/39Ar age spectrum analysis. Microcline separates from deep drill hole intersections with Eocene to Miocene sediments in the Basin and Tejon Blocks of the southern San Joaquin Valley, California, analysed by the age spectrum approach show radiogenic 40Ar (40Ar*) gradients that record both the slow cooling of the uplifting sediment source approx.= 65 Ma ago, and a recent thermal event. This information, in conjunction with the observation of fission track annealing in the coexisting apatites, allows estimation of the temperature-time conditions of this thermal event at about 1400C for approx.= 200 ka. Present and paleotemperature data is in accord with heating related to several kilometers of Pleistocene sediment deposition. Heat flow calculations suggest that this recent subsidence has depressed the thermal gradient from about 300C km-1 to the present apparent gradient of 240C km-1. 40Ar/39Ar analysis of detrital microcline crystals yields thermochronological information in the temperature-time range of petroleum maturation and provides this technique with potential as both a useful exploration tool and as a means of probing the fundamental geodynamic processes of basin evolution. (orig.)

  19. Magnitude-frequency distribution of submarine landslides in the Gioia Basin (southern Tyrrhenian Sea)

    Science.gov (United States)

    Casas, D.; Chiocci, F.; Casalbore, D.; Ercilla, G.; de Urbina, J. Ortiz

    2016-07-01

    Regional inventories and magnitude-frequency relationships provide critical information about landslides and represent a first step in landslide hazard assessment. Despite this, the availability of accurate inventories in the marine environment remains poor because of the commonly low accessibility of high-resolution data at regional scales. Evaluating high-resolution bathymetric data spanning the time interval 2007-2011 for the Gioa Basin of the southern Tyrrhenian Sea yielded a landslide inventory of 428 events affecting an area of >85 km2 and mobilizing approximately 1.4 km3 of sediment. This is the first time that this area is studied in such detail, justifying comparison with other areas both onland and offshore. Statistical analyses revealed that the cumulative distribution of the dataset is characterized by two right-skewed probability distributions with a heavy tail. Moreover, evidence of a rollover for smaller landslide volumes is consistent with similar trends reported in other settings worldwide. This may reflect an observational limitation and the site-specific geologic factors that influence landslide occurrence. The robust validation of both power-law and log-normal probability distributions enables the quantification of a range of probabilities for new extreme events far from the background landslide sizes defined in the area. This is a useful tool at regional scales, especially in geologically active areas where submarine landslides can occur frequently, such as the Gioia Basin.

  20. Controls on Suspended Sediment Concentrations and Turbidity within a Reforested, Southern Appalachian Headwater Basin

    Directory of Open Access Journals (Sweden)

    Jerry R. Miller

    2015-06-01

    Full Text Available Water quality data collected between 2007 and 2014 within the Allen Creek Watershed were used to: (1 determine the factors controlling the temporal variations in turbidity and suspended sediment concentration (SSC within a representative, high-gradient headwater basin in the Southern Appalachians; and (2 assess the recovery of water quality following extensive logging operations during the early to mid-1900s. Regression analysis suggests that suspended sediment is primarily derived from upland areas and variations in concentration reflect rainfall intensity and total event precipitation. Overall, SSC and turbidity were low in stream waters in comparison to both reference values for stable streams and more developed basins in the region. Some floods were characterized by high SSC values, but limited turbidity and vice versa. Differences in measured SSC and turbidity between storms reflect different controls on the two parameters, and the apparent influence of natural organic matter on turbidity during rainfall events that are incapable of transporting sediment to the channel via overland flow. Low SSC and turbidity values are presumably related to the reforestation of hillslopes and riparian buffers following the cessation of logging operations. They also are due to a historical reduction in the sedimentological connectivity of hillslopes and tributaries with the axial channel that occurred during logging operations.

  1. Magnetic mineralogy analyses on greigite-bearing sediments with inconsistent magnetic polarity (Adana Basin, Southern Turkey)

    Science.gov (United States)

    Lucifora, S.; Cifelli, F.; Mattei, M.; Cosentino, D.; Sagnotti, L.; Roberts, A.

    2012-04-01

    A paleomagnetic study has been carried out, in the framework of the VAMP (Vertical Anatolian Movement Project) project, on 4 stratigraphic sections and 1 site from the Adana basin in the southern margin of the Anatolian Plateau. About 300 standard cylindrical samples have been analysed for paleomagnetism and rock magnetism. All the sections have been deposited in the upper Messinian"lago-mare" post-evaporitic event, which occurred in the Mediterranean basin, during the reverse polarity Chron C3r. Paleomagnetic results, presented in this work, are in contrast with these data, showing both normal and reverse polarities along the sections. Standard magnetic mineralogy investigations, integrated with SEM analyses and FORC diagrams, show that magnetite and ferrimagnetic iron sulphides (greigite) are the main magnetic carriers. Moreover, we find an interesting correlation between the magnetic mineralogy of the sediments and the magnetic polarities, being magnetite the magnetic carrier in the normal polarity samples and greigite in the reverse ones. Reversal and fold tests demonstrate that normal polarity samples have been subjected to a pervasive magnetic overprint and acquired their remanent magnetization after bedding tilt. Whereas samples with a reverse polarity acquired their remanent magnetization before bedding tilt, but after syn-sedimentary soft deformation. This work is proposed as a contribution aimed to improve the understanding of the relationship between the magnetic mineralogy and the remagnetization phenomena in order to avoid misinterpretation of magnetostratigraphic and paleomagnetic data.

  2. Integrated ICTs for Water Basins Management in Southern Africa: Systematic Review and Meta-analyses for Perceived Relevance Criteria

    Directory of Open Access Journals (Sweden)

    H. Mongi

    2016-06-01

    Full Text Available User-focused design and an implementation of a computer-based Information System (IS or Information Technology (IT are considered to play a key role in enhancing adoption, supporting activities and contributing to the sector specific sustainability goals. However, there are general concerns over the practical applications derived from records of failure rates of IS/IT projects in the developing world. This paper aggregates and analyzes stakeholders’ perceived usefulness criteria that were documented from water basin focusing on IS and related projects in Southern Africa. Systematic literature reviews and meta-analysis were adopted for data collection and analyses. Literature with academic, practice and hybrid viewpoints was collected from five water basins in Southern Africa. Designed data collection flow chart guided the search for appropriate literature. Analyses of the data were performed by using Statistical Package for Social Sciences (SPSS. Results of the search were classified and presented basing on the domain, yearly waves from 2000 to 2015, trans-basin nature and basin of focus. Literature was distributed across the classes at different magnitudes. The study has found out that relevance criteria as measure of usefulness have been incorporated in designing and implementing the IS/IT projects in the river basins. However, incorporation of relevance criteria was periodically increasing with technological advancement and increasing complexity of managing the water basins. In general, it was responsive to increasing challenges of water resources in the developing countries. This anticipated better results at the levels of output, outcome and impacts of IS/IT projects in the Southern Africa. The study concludes that the current trends of incorporation of the relevance criteria in designing and implementing the IS/IT projects on water resources are potential for impact-based interventions in Southern Africa.

  3. Biostratigraphy of a Paleocene-Eocene Foreland Basin boundary in southern Tibet

    Institute of Scientific and Technical Information of China (English)

    Xiaoqiao Wan; Xi Wang; Luba F.Jansa

    2010-01-01

    This study of the Paleocene-Eocene boundary within a foreland basin of southern Tibet,which was dominated by a carbonate ramp depositional environment, documents more complex environmental conditions than can be derived from studies of the deep oceanic environment. Extinction rates for larger foraminiferal species in the Zongpu-1 Section apply to up to 46% of the larger foraminiferal taxa.The extinction rate in southern Tibet is similar to rates elsewhere in the world, but it shows that the Paleocene fauna disappeared stepwise through the Late Paleocene, with Eocene taxa appearing abruptly above the boundary. A foraminifera turnover was identified between Members 3 and 4 of the Zongpu Formation-from the Miscellanea-Daviesina assemblage to an Orbitolites-Alveolina assemblage. The Paleocene and Eocene boundary is between the SBZ 4 and SBZ 5, where it is marked by the extinction of Miscellanea miscella and the first appearance of Alveolina ellipsodalis and a large number of Orbitolites.Chemostratigraphically, the δ13C values from both the Zongpu-1 and Zongpu-2 Sections show three negative excursions in the transitional strata, one in Late Paleocene, one at the boundary, and one in the early Eocene. The second negative excursion of δ13C, which is located at the P-E boundary, coincides with larger foraminifera overturn. These faunal changes and the observed δ13C negative excursions provide new evidence on environmental changes across the Paleocene-Eocene boundary in Tibet.

  4. LA-ICP-MS zircon U-Pb dating from granitoids in southern basement of Songliao basin: Constraints on ages of the basin basement

    Institute of Scientific and Technical Information of China (English)

    GAO FuHong; XU WenLiang; YANG DeBin; PEI FuPing; LIU XiaoMing; HU ZhaoChu

    2007-01-01

    Seven LA-ICP-MS zircon U-Pb datings from granitoids in the southern basement of the Songliao basin were done in order to constrain the ages of the basin basement. The cathodoluminescence (CL) images of the zircons from seven granitoids indicate that they are euhedral-subhedral ones with striped absorption and obvious oscillatory zoning rims. The dating results show that a weighted mean 206Pb/238U age is 236±3 Ma for quartz diorite (sample No.T6-1) located in the western slope of the basin, that weighted mean 206Pb/238U ages are 319±1 Ma (2126 m) and 361±2 Ma (1994 m) for diorite (sample No.YC1-1) and granite (sample No.YC1-2) located in northern part of southeastern uplift of the basin, respectively, and that weighted mean 206Pb/238U ages are 161±5 Ma, 165±2 Ma, 165±1 Ma and 161±4 Ma for samples Q2-1, SN121, SN122, and SN72 granitoids located in southern part of southeastern uplift of the basin, respectively. The statistical results of ages suggest that the middle Jurassic granitoids constitute the main part of basement granitoids, and that the Hercynian and Indo-Sino magmatisms also occur in the basin basement. It is implied that the Songliao basin should be a rift one formed in the intracontinent or active continental margin settings in the late Mesozoic after the Middle Jurassic orogeny took place.

  5. Modeling of soil erosion and sediment transport in the East River Basin in southern China

    Science.gov (United States)

    Wu, Yping; Chen, Ji

    2012-01-01

    Soil erosion is a major global environmental problem that has caused many issues involving land degradation, sedimentation of waterways, ecological degradation, and nonpoint source pollution. Therefore, it is significant to understand the processes of soil erosion and sediment transport along rivers, and this can help identify the erosion prone areas and find potential measures to alleviate the environmental effects. In this study, we investigated soil erosion and identified the most seriously eroded areas in the East River Basin in southern China using a physically-based model, Soil and Water Assessment Tool (SWAT). We also introduced a classical sediment transport method (Zhang) into SWAT and compared it with the built-in Bagnold method in simulating sediment transport process along the river. The derived spatial soil erosion map and land use based erosion levels can explicitly illustrate the identification and prioritization of the critical soil erosion areas in this basin. Our results also indicate that erosion is quite sensitive to soil properties and slope. Comparison of Bagnold and Zhang methods shows that the latter can give an overall better performance especially in tracking the peak and low sediment concentrations along the river. We also found that the East River is mainly characterized by sediment deposition in most of the segments and at most times of a year. Overall, the results presented in this paper can provide decision support for watershed managers about where the best management practices (conservation measures) can be implemented effectively and at low cost. The methods we used in this study can also be of interest in sediment modeling for other basins worldwide.

  6. [Hyphessobrycon taphorni and H. eschwartzae (Teleostei: Characidae) two new species of fish in the basin of Madre de Dios river, Peru].

    Science.gov (United States)

    Garcia-Alzate, Carlos A; Romin-Valencia, César; Ortega, Hernán

    2013-06-01

    Hyphessobrycon with 129 valid species, is a genus of fish that has a great diversity of species in the Neotropical ichthyofauna, reaches its greatest diversity in the Amazon basin with about 70% of these species, is highly desired by hobbyists because of their beauty and color, and are still meeting new species. We analyzed specimens from the Departamento de Ictiología, Museo de Historia Natural de la Universidad Mayor de San Marcos, Lima, Perú (MUSM); and measurements of the specimens were taken point to point with digital calipers. Observations of bone and cartilage structures were made on cleared and stained (C&S) samples. The morphometric relationships between species using 21 variables were explored using a principal component analysis (PCA). Here we describe two new species, Hyphessobrycon taphorni and H. eschwartzae from the Madre de Dios River drainage, Peru. Hyphessobrycon taphorni sp. n. can be distinguished by the number of dorsal-fin rays (iii, 8), by the number of: pored lateral-line scales (4-5), teeth in the outer premaxillary row (1-2), teeth in the inner premaxillary row (7-8), by: the caudal-peduncle length (11.4-16.4% SL), number of lateral scales (28-29, except from H. loretoensis which has 29-30) and absence of a humeral spot (vs. present), it differs from H. loretoensis by the number of: scales between the lateral line and the anal fin origin (4 vs. 3) and maxillary teeth (2 vs. 3-4), and it differs from H. agulha by the number of branched pectoral-fin rays (11-12 vs. 9-10). Hyphessobrycon eschwartzae sp. n. is distinguished by the number of: simple anal-fin rays (iv), teeth on the dentary (13-15), teeth in the inner premaxillary row (6), teeth in the outer premaxillary row (3, except from H. heterorhabdus and H. loretoensis which have 3-4); it differs from H. loretoensis by the number of: pored lateral-line scales (7 vs. 9-10), scales between the lateral line and the dorsal-fin origin (5 vs. 3-4); it differs from H. agulha in the number of

  7. [Hyphessobrycon taphorni and H. eschwartzae (Teleostei: Characidae) two new species of fish in the basin of Madre de Dios river, Peru].

    Science.gov (United States)

    Garcia-Alzate, Carlos A; Romin-Valencia, César; Ortega, Hernán

    2013-06-01

    Hyphessobrycon with 129 valid species, is a genus of fish that has a great diversity of species in the Neotropical ichthyofauna, reaches its greatest diversity in the Amazon basin with about 70% of these species, is highly desired by hobbyists because of their beauty and color, and are still meeting new species. We analyzed specimens from the Departamento de Ictiología, Museo de Historia Natural de la Universidad Mayor de San Marcos, Lima, Perú (MUSM); and measurements of the specimens were taken point to point with digital calipers. Observations of bone and cartilage structures were made on cleared and stained (C&S) samples. The morphometric relationships between species using 21 variables were explored using a principal component analysis (PCA). Here we describe two new species, Hyphessobrycon taphorni and H. eschwartzae from the Madre de Dios River drainage, Peru. Hyphessobrycon taphorni sp. n. can be distinguished by the number of dorsal-fin rays (iii, 8), by the number of: pored lateral-line scales (4-5), teeth in the outer premaxillary row (1-2), teeth in the inner premaxillary row (7-8), by: the caudal-peduncle length (11.4-16.4% SL), number of lateral scales (28-29, except from H. loretoensis which has 29-30) and absence of a humeral spot (vs. present), it differs from H. loretoensis by the number of: scales between the lateral line and the anal fin origin (4 vs. 3) and maxillary teeth (2 vs. 3-4), and it differs from H. agulha by the number of branched pectoral-fin rays (11-12 vs. 9-10). Hyphessobrycon eschwartzae sp. n. is distinguished by the number of: simple anal-fin rays (iv), teeth on the dentary (13-15), teeth in the inner premaxillary row (6), teeth in the outer premaxillary row (3, except from H. heterorhabdus and H. loretoensis which have 3-4); it differs from H. loretoensis by the number of: pored lateral-line scales (7 vs. 9-10), scales between the lateral line and the dorsal-fin origin (5 vs. 3-4); it differs from H. agulha in the number of

  8. Abundance and Morphological Effects of Large Woody Debris in Forested Basins of Southern Andes

    Science.gov (United States)

    Andreoli, A.; Comiti, F.; Lenzi, M. A.

    2006-12-01

    The Southern Andes mountain range represents an ideal location for studying large woody debris (LWD) in streams draining forested basins thanks to the presence of both pristine and managed woodland, and to the general low level of human alteration of stream corridors. However, no published investigations have been performed so far in such a large region. The investigated sites of this research are three basins (9-13 km2 drainage area, third-order channels) covered by Nothofagus forests: two of them are located in the Southern Chilean Andes (the Tres Arroyos in the Malalcahuello National Reserve and the Rio Toro within the Malleco Natural Reserve) and one basin lies in the Argentinean Tierra del Fuego (the Buena Esperanza basin, near the city of Ushuaia). Measured LWD were all wood pieces larger than 10 cm in diameter and 1 m in length, both in the active channel and in the adjacent active floodplain. Pieces forming log jams were all measured and the geometrical dimensions of jams were taken. Jam type was defined based on Abbe and Montgomery (2003) classification. Sediment stored behind log-steps and valley jams was evaluated approximating the sediment accumulated to a solid wedge whose geometrical dimensions were measured. Additional information relative to each LWD piece were recorded during the field survey: type (log, rootwad, log with rootwads attached), orientation to flow, origin (floated, bank erosion, landslide, natural mortality, harvest residuals) and position (log-step, in-channel, channel-bridging, channel margins, bankfull edge). In the Tres Arroyos, the average LWD volume stored within the bankfull channel is 710 m3 ha-1. The average number of pieces is 1,004 per hectare of bankfull channel area. Log-steps represent about 22% of all steps, whereas the elevation loss due to LWD (log-steps and valley jams) results in 27% loss of the total stream potential energy. About 1,600 m3 of sediment (assuming a porosity of 20%) is stored in the main channel

  9. International Uranium Resources Evaluation Project (IUREP) orientation phase mission report: Peru. August - October 1981

    International Nuclear Information System (INIS)

    The IUREP Orientation Phase Mission to Peru believes that the Speculative Resources of that country fall between 6,000 and 11,000 tonnes uranium. There has been no uranium production in Peru and there are no official estimates of uranium resources. Past exploration in Peru (dating from about 1952) has indicated a paucity of valid uranium occurrences and radioactive anomalies. Only recently (1980) have anomalous areas been identified, (Macusani-Picotani). The identified Speculative Resources are mainly in Late Tertiary ignimbrites and associated sediments in the high Andes of southern Peru. Geologically, there are direct parallels between these resources and deposits of the Los Frailes areas of neighbouring Bolivia. Other minor Speculative Resources may be present in calcretes developed from Tertiary volcanogenic sources over the Precambrian in the Pacific Coastal desert of southern Peru but no positive indications have been recognised. Hercynian sub-volcanic granites in the eastern cordillera of southern Peru may have some associated Speculative Resources both intra and extra granitic. No Speculative Potential could be identified in Permo-Triassic or Tertiary post tectonic continental sediments anywhere in Peru. Such potential may exist but further reconnaissance of the continental late Tertiary basins, with positive indications would be required before inclusion of potential in this category. Recent discoveries in the volcanogenic environment of southern Peru have been by carborne, helicopter borne and on on-foot reconnaissance of isolated areas. It is recommended that there be a more systematic, integrated study of the entire volcanic district assisted by volcanic petrographic examination. Assessment of the known occurrences requires immediate subsurface study by drilling and exploration audits to assess their continuity, grade variation and thickness. This phase will be significantly more expensive than previous exploration. Non-core drilling should supplement

  10. Seismicity induced petroleum migration: field and subsurface observations in Talara basin (northwestern Peru); Migracao de petroleo induzida por sismicidade: observacoes de campo e de subsuperficie na bacia de Talara (noroeste do Peru)

    Energy Technology Data Exchange (ETDEWEB)

    Daudt, Jose Alfredo Borges; Pozo, Eloy Gerardo [Petrobras Energia Peru, Lima (Peru)], Emails: jdaudt@petrobras-usa.com, eloy.pozo@petrobras.com; Benedicto, Antonio [Universite Paris Sud XI (France). Lab. de Tectonique], Email: antonio.benedicto-esteban@u-psud.fr

    2009-05-15

    The objective of this communication is to report observations made in some outcrops of oil in the Quebrada Viejo, a lower affluent of the Quebrada Mogollon, before and after of the seismic event occurred on April 22, 2007 in Talara. Additionally, it was analyzed the data productions of the total fluids (water plus oil) of the 21 wells of the Lot X (area under concession of the PETROBRAS Energia Peru), in the day before, the day of the event and the day after of the seismic event in order to check for productive anomalies during the period.

  11. An Approach for Including Uncertainty in Integrated Water Resources Assessments within Large River Basins of Southern Africa.

    Science.gov (United States)

    Hughes, D.

    2015-12-01

    There are many large basins in southern Africa that are mostly ungauged but may have some streamflow observations either on the main river or on tributaries. Many of the streamflow records are, however, of poor quality or impacted by largely unquantified and non-stationary development impacts. All water resources assessments are therefore uncertain and model setups are difficult to validate in traditional ways. The paper presents a method for practical uncertainty assessment using a semi-distributed (sub-basin) model. The method uses a 2-stage approach where the first stage involves obtaining 'behavioural' parameter sets to represent the incremental natural streamflow for each sub-basin. The criteria for 'behavioural' are based on a series of constraints on model output that can be developed from the available gauged data or from regional assessments of natural hydrological functioning. The second stage simulates the whole basin based on sampling the 'behavioural' incremental flow parameter sets, as well as samples of additional individual parameter values representing downstream routing parts of the model and development impacts. One of the perceived advantage of the method is that all the ensembles at the total basin outlet are made up of behavioural inputs for all sub-basins. The method is also flexible in terms of the uncertainty range of the constraints, which might be expected to be narrow (low uncertainty) in well gauged sub-basins, or areas where our understanding of flow regime characteristics is good, but much wider (higher uncertainty) in other parts of the basin. The paper briefly explains the approach and discusses some of the issues associated with its application using examples from southern Africa.

  12. Thermal and Evolved Gas Analysis (TEGA) of hyperarid soils doped with microorganisms from the Atacama Desert in southern Peru (Pampas de la Joya): Implications for the Phoenix Mission

    Science.gov (United States)

    Valdivia-Silva, Julio E.; Navarro-Gonzalez, Rafael; McKay, Chris

    TEGA is one of several instruments on board of the Phoenix Lander that will perform differential scanning calorimetry and evolved gas analysis of soil samples and ice, collected from the surface and subsurface at a northern landing site on Mars. TEGA is a combination of a high-temperature furnace and a mass spectrometer that will be use to analyze samples delivered to instrument via a robotic arm. The samples will be heated at a programmed ramp rate up to 1000° C and the power required for heating will be carefully and continuously monitored (scanning calorimetry). The evolved gases generated during the process will be analyzed with the evolved-gas analyzer (a magnetic sector mass spectrometer) in order to determine the composition of gases released as a function of temperature. Our laboratory has developed a sample characterization method using a pyrolizer integrated to a quadrupole mass spectrometer to support the interpretations of TEGA data. Here we examine the thermal and evolved gas properties of six types of hyperarid soils from the Pampas de La Joya southern Peru, a possible analog to Mars, which has been previously enriched with microorganisms (Salmonella thypimurium, Micrococcus luteus, and Candida albicans) to investigate the effect of soil matrix over TEGA response. Between 20 to 40 mg of soil pre-treated to 500° C for 24 hours to remove traces of organics, was mixed with or without 5mg biomass lyophilized (dry weight). Additionally 20 mg of each one microorganism were analyzed. The samples were placed in the pyrolizer that reached 1200° C at 1 hour. The volatiles released were transferred to the MS using helium as a carrier gas. The quadrupole MS was ran in scan mode from 40-350m/z. As expected, there were significant differences in the evolved gas behaviors for microorganism samples with or without a soil matrix under similar heating conditions. In addition, samples belonging to the most arid environments had significant differences compared with

  13. Thermally evolved gas analysis (TEGA) of hyperarid soils doped with microorganisms from the Atacama Desert in southern Peru: Implications for the Phoenix mission

    Science.gov (United States)

    Valdivia-Silva, Julio E.; Navarro-González, Rafael; McKay, Christopher

    2009-07-01

    TEGA, one of several instruments on board of the Phoenix Lander, performed differential scanning calorimetry and evolved gas analysis of soil samples and ice, collected from the surface and subsurface at a northern landing site on Mars. TEGA is a combination of a high temperature furnace and a mass spectrometer (MS) that was used to analyze samples delivered to the instrument via a robotic arm. The samples were heated at a programmed ramp rate up to 1000 °C. The power required for heating can be carefully and continuously monitored (scanning calorimetry). The evolved gases generated during the process can be analyzed with the evolved gas analyzer (a magnetic sector mass spectrometer) in order to determine the composition of gases released as a function of temperature. Our laboratory has developed a sample characterization method using a pyrolyzer integrated to a quadrupole mass spectrometer to support the interpretations of TEGA data. Here we examine the evolved gas properties of six types of hyperarid soils from the Pampas de La Joya in southern Peru (a possible analog to Mars), to which we have added with microorganisms ( Salmonella typhimurium, Micrococcus luteus, and Candida albicans) in order to investigate the effect of the soil matrix on the TEGA response. Between 20 and 40 mg of soil, with or without ˜5 mg of lyophilized microorganism biomass (dry weight), were placed in the pyrolyzer and heated from room temperature to 1200 °C in 1 h at a heating rate of 20 °C/min. The volatiles released were transferred to a MS using helium as a carrier gas. The quadrupole MS was ran in scan mode from 10 to 200 m/z. In addition, ˜20 mg of each microorganism without a soil matrix were analyzed. As expected, there were significant differences in the gases released from microorganism samples with or without a soil matrix, under similar heating conditions. Furthermore, samples from the most arid environments had significant differences compared with less arid soils

  14. Basin-and Mountain-Building Dynamic Model of "Ramping-Detachment-Compression" in the West Kunlun-Southern Tarim Basin Margin

    Institute of Scientific and Technical Information of China (English)

    CUI Junwen; LI Pengwu; GUO Xianpu; DING Xiaozhong; TANG Zhemin

    2008-01-01

    -present compression-rapid uplift and strong subsidence, when the basin- and mountain-forming processes were simultaneously controlled by north-vergent thrust propagation and compression. The authors summarize the processes as the "ramping-detachment-compression basin- and mountain-forming dynamic model". The basin-range tectonics was initiated in the Late Jurassic, the Miocene-Piiocene were a major transition period for the basin- and mountain-forming mechanism and the terminal early Pleistocene tectonic movement in the main laid a foundation for the basin-and-mountain tectonic framework in the West Kunlun-southern Tarim basin margin.

  15. Jurassic sedimentary evolution of southern Junggar Basin:Implication for palaeoclimate changes in northern Xinjiang Uygur Autonomous Region, China

    Institute of Scientific and Technical Information of China (English)

    Shun-Li Li; Xing-He Yu; Cheng-Peng Tan; Ronald Steel

    2014-01-01

    Junggar Basin, located in northern Xinjiang, presents continuous and multi-kilometer-thick strata of the Jurassic deposits. The Jurassic was entirely terrestrial lfuvial and lacustrine deltaic sedimentation. Eight outcrop sections across the Jurassic strata were meas-ured at a resolution of meters in southern Junggar Basin. Controlling factors of sedimentary evolution and palaeoclimate changes in Junggar Basin during the Jurassic were discussed based on lithology, fossils and tectonic setting. In the Early to Middle Jurassic, the warm and wide Tethys Sea generated a strong monsoonal circulation over the central Asian continent, and provided adequate moisture for Junggar Basin. Coal-bearing strata of the Badaowan, Sangonghe, and Xishanyao Formations were developed under warm and humid palaeocli-mate in Junggar Basin. In the late Middle Jurassic, Junggar Basin was in a semi-humid and semi-arid environment due to global warming event. Stratigraphy in the upper part of the Mid-dle Jurassic with less plant fossils became multicolor or reddish from dark color sediments. During the Late Jurassic, collision of Lhasa and Qiangtang Block obstructed monsoon from the Tethys Sea. A major change in climate from semi-humid and semi-arid to arid conditions took place, and reddish strata of the Upper Jurassic were developed across Junggar Basin.

  16. Gravity analysis of the Precambrian basement topography associated with the northern boundary of Ghadames Basin (southern Tunisia)

    Science.gov (United States)

    Dhaoui, Mohamed; Gabtni, Hakim; Jallouli, Chokri; Jleilia, Ali; Mickus, Kevin Lee; Turki, Mohamed Moncef

    2014-12-01

    Gravity data were analyzed to determine the structural development of the northern boundary of the Ghadames Basin in southern Tunisia. The Ghadames Basin which also occurs in eastern Algeria and northwestern Libya is one of the most prolific hydrocarbon producers in North Africa with several of the largest oil fields occurring along its northern boundary. The Ghadames Basin was formed during a series of tectonic events ranging from the Early Paleozoic to the Early Cenozoic. These tectonic events produced a basin in southern Tunisia that has a complex basement configuration which is not completely known. A residual gravity anomaly map constructed using polynomial trend surfaces, and vertical and horizontal gravity derivative maps indicate that the northern boundary contains a series of maxima and minima anomalies that trend in two prominent directions: northeast-southwest and east-west. The horizontal and vertical derivative gravity anomaly maps indicate that the width of the basement structures range between 10 and 20 km in width. Three-dimensional (3D) Euler deconvolution and 3D forward modeling constrained by well data, one seismic reflection profile and remote sensing data confirm the width of the basement structures and indicates that the depth of basin varies between 1.5 and 5 km, with deeper sections in general more numerous in the southern sections of the boundary. The gravity analysis constrained by the seismic reflection profile and well data implies that the basement topography may have been formed during the Pan African and/or late Mesozoic rifting. However, additional seismic reflection and well data are needed to confirm this conclusion. The discovery of the numerous basement structures suggests that there may exist additional hydrocarbon traps within the northern boundary of the Ghadames Basin.

  17. Intraplate deformation of the Al Qarqaf Arch and the southern sector of the Ghadames Basin (SW Libya)

    Science.gov (United States)

    Carruba, Stefano; Perotti, Cesare; Rinaldi, Marco; Bresciani, Ilenia; Bertozzi, Giuseppe

    2014-09-01

    The structural evolution of the Al Qarqaf Arch (Libya) and the southern sector of the Ghadames Basin were reconstructed by the integration of remote sensing analysis, 2D seismic lines, well log data and geological maps. The Al Qarqaf Arch (Libya) is a wide, gentle warping of pre-Cambrian and Palaeozoic rocks that forms the southern boundary of the Ghadames Basin, a large Palaeozoic intracratonic basin of the Saharan Platform. Surface and subsurface analyses revealed the presence of different phases of intracratonic deformations, related to the Al Qarqaf Arch uplift and Ghadames Basin development. Extensional tectonic phases prevailed in the study area up until the Devonian, while compressional folding and structural inversion affected the region during Late Carboniferous and Mesozoic, indicating that compressional horizontal stresses affected the plate interior, giving rise to intraplate tectonics. Three major unconformities (Intra-Silurian, Silurian-Devonian transition and Upper Carboniferous unconformities) outline these tectonic events related to the upwarping of the arch and the downwarping of the basin.

  18. Description of Lutzomyia (Trichophoromyia) nautaensis n. sp. (Diptera: Psychodidae) from the Peruvian Amazon Basin.

    Science.gov (United States)

    Fernandez, Roberto; Lopez, Victor; Cardenas, Roldan; Requena, Edwin

    2015-07-01

    A new species of sand fly, which we describe as Lutzomyia (Trichophoromyia) nautaensis n. sp., was collected in the northern Peruvian Amazon Basin. In this region of Peru, cutaneous leishmaniasis is transmitted primarily by anthropophilic sand flies; however, zoophilic sand flies of the subgenus Trichophoromyia may also be incriminated in disease transmission. Detection of Leishmania spp. in Lutzomyia auraensis Mangabeira captured in the southern Peruvian Amazon indicates the potential of this and other zoophilic sand flies for human disease transmission, particularly in areas undergoing urban development. Herein, we describe Lutzomyia (Trichophoromyia) nautaensis n. sp., and report new records of sand flies in Peru. PMID:26335468

  19. Description of Lutzomyia (Trichophoromyia) nautaensis n. sp. (Diptera: Psychodidae) from the Peruvian Amazon Basin.

    Science.gov (United States)

    Fernandez, Roberto; Lopez, Victor; Cardenas, Roldan; Requena, Edwin

    2015-07-01

    A new species of sand fly, which we describe as Lutzomyia (Trichophoromyia) nautaensis n. sp., was collected in the northern Peruvian Amazon Basin. In this region of Peru, cutaneous leishmaniasis is transmitted primarily by anthropophilic sand flies; however, zoophilic sand flies of the subgenus Trichophoromyia may also be incriminated in disease transmission. Detection of Leishmania spp. in Lutzomyia auraensis Mangabeira captured in the southern Peruvian Amazon indicates the potential of this and other zoophilic sand flies for human disease transmission, particularly in areas undergoing urban development. Herein, we describe Lutzomyia (Trichophoromyia) nautaensis n. sp., and report new records of sand flies in Peru.

  20. The oil and gas market in Peru

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-06-01

    Petroleum companies in Peru have scheduled investments of $298.5 million for exploration activities for year 2000, which is double the 1999 investment. The demand for oil in Peru is about 140,000 barrels per day, of which local production can supply 106,00 b/d. In 2000, imports of crude oil were worth approximately $447.7 million. The 18 sedimentary basins throughout Peru are estimated to contain 16 billion barrels of crude oil reserves. The greatest exploration activity took place in the Talara basin, while only limited exploration took place in the Maranon and Ucayali basins. The discovery of the Camisea and Aguaytia gas fields present significant potential for development, particularly for foreign investment. Upstream development of the $4.5 billion Camisea project will be undertaken by a consortium of international companies and is expected to be completed by 2004. In addition, Aguaytia Energy is working on a pipeline construction project worth up to $3 million. Canadian oil and gas companies will find opportunities to supply equipment and services for drilling wells, petroleum and natural gas pipelines, and production and storage facilities for petroleum and natural gas. United States, Argentina, Brazil, Japan and the European Union are the main foreign competitors in Peru. It is recommended that foreign companies make use of a local agent when conducting business in Peru. refs., tabs.

  1. Identifying needs for streamflow forecasting in the Incomati basin, Southern Africa

    Science.gov (United States)

    Sunday, Robert; Werner, Micha; Masih, Ilyas; van der Zaag, Pieter

    2013-04-01

    Despite being widely recognised as an efficient tool in the operational management of water resources, rainfall and streamflow forecasts are currently not utilised in water management practice in the Incomati Basin in Southern Africa. Although, there have been initiatives for forecasting streamflow in the Sabie and Crocodile sub-basins, the outputs of these have found little use because of scepticism on the accuracy and reliability of the information, or the relevance of the information provided to the needs of the water managers. The process of improving these forecasts is underway, but as yet the actual needs of the forecasts are unclear and scope of the ongoing initiatives remains very limited. In this study questionnaires and focused group interviews were used to establish the need, potential use, benefit and required accuracy of rainfall and streamflow forecasts in the Incomati Basin. Thirty five interviews were conducted with professionals engaged in water sector and detailed discussions were held with water institutions, including the Inkomati Catchment Management Agency (ICMA), Komati Basin Water Authority (KOBWA), South African Weather Service (SAWS), water managers, dam operators, water experts, farmers and other water users in the Basin. Survey results show that about 97% of the respondents receive weather forecasts. In contrast to expectations, only 5% have access to the streamflow forecast. In the weather forecast, the most important variables were considered to be rainfall and temperature at daily and weekly time scales. Moreover, forecasts of global climatic indices such as El Niño or La Niña were neither received nor demanded. There was limited demand and/or awareness of flood and drought forecasts including the information on their linkages with global climatic indices. While the majority of respondents indicate the need and indeed use the weather forecast, the provision, communication and interpretation were in general found to be with too

  2. Low flows and reservoir management for the Durance River basin (Southern France) in the 2050s

    Science.gov (United States)

    Sauquet, Eric

    2015-04-01

    The Durance River is one of the major rivers located in the Southern part of France. Water resources are under high pressure due to significant water abstractions for human uses within and out of the natural boundaries of the river basin through an extended open channel network. Water demands are related to irrigation, hydropower, drinking water, industries and more recently water management has included water needs for recreational uses as well as for preserving ecological services. Water is crucial for all these activities and for the socio-economic development of South Eastern France. Both socio-economic development and population evolution will probably modify needs for water supply, irrigation, energy consumption, tourism, industry, etc. In addition the Durance river basin will have to face climate change and its impact on water availability that may question the sustainability of the current rules for water allocation. The research project R²D²-2050 "Risk, water Resources and sustainable Development within the Durance river basin in 2050" aims at assessing future water availability and risks of water shortage in the 2050s by taking into account changes in both climate and water management. R²D²-2050 is partially funded by the French Ministry in charge of Ecology and the Rhône-Méditerranée Water Agency. This multidisciplinary project (2010-2014) involves Irstea, Electricité de France (EDF), the University Pierre et Marie Curie (Paris), LTHE (CNRS), the Société du Canal de Provence (SCP) and the research and consultancy company ACTeon. A set of models have been developed to simulate climate at regional scale (given by 330 projections obtained by applying three downscaling methods), water resources (provided by seven rainfall-runoff models forced by a subset of 330 climate projections), water demand for agriculture and drinking water, for different sub basins of the Durance River basin upstream of Mallemort under present day and under future conditions

  3. Identification of hydrogeochemical processes in groundwater of Dawa River basin, southern Ethiopia.

    Science.gov (United States)

    Woldemariyam, Fikadu; Ayenew, Tenalem

    2016-08-01

    Dawa River basin in southern Ethiopia is covered by volcanic, basement, and sedimentary rocks. Locating good quality groundwater is a challenge in most parts of the basin. Statistical analysis and graphical plots of 94 hydrochemical data of groundwater were used as a main tool to acquire an insight into the major processes that control groundwater chemistry. In the volcanic terrain groundwater is dilute (mean total dissolved solids (TDS): 152 mg/l), while salinity is the highest in the sedimentary terrain (mean TDS: 1750 mg/l). NO3 (-) varies from below the detection limit to 433 mg/l NO3 (-). In 26 % of the water samples, nitrate concentration is above the human-affected value, 5 mg/l NO3 (-). In 6 % of the samples, NO3 (-) concentration is above the limit recommended in drinking water, 50 mg/l NO3 (-), by WHO. Concentration range of the other major ions is also high and hydrochemical water types are diverse, suggesting the effect of various hydrogeochemical processes on the water chemistry. Chemical data analysis revealed that in the volcanic and most parts of the basement terrains silicate hydrolysis is the dominant process. Gypsum dissolution is the main process in the sedimentary terrain. Dissolution of gypsum is also important at few locations along dry riverbeds in the semiarid area where the effect of evaporation on the water chemistry is considerable. Loading of factors with K(+) and SO4 (2-), K(+) and NO3 (-), and NO3 (-) and correlation of SO4 (2-) with Cl(-), along with the observed high nitrate concentration, indicate the effect of surface contamination sources on the water quality. PMID:27456694

  4. Nutrient maximums related to low oxygen concentrations in the southern Canada Basin

    Institute of Scientific and Technical Information of China (English)

    JIN Ming-ming; SHI Jiuxin; LU Yong; CHEN Jianfang; GAO Guoping; WU Jingfeng; ZHANG Haisheng

    2005-01-01

    The phenomenon of nutrient maximums at 70~200 m occurred only in the region of the Canada Basin among the world oceans. The prevailing hypothesis was that the direct injection of the low-temperature high-nutrient brines from the Chukchi Sea shelf (<50 m) in winter provided the nutrient maximums. However, we found that there are five problems in the direct injection process. Formerly Jin et al. considered that the formation of nutrient maximums can be a process of locally long-term regeneration. Here we propose a regeneration-mixture process. Data of temperature, salinity, oxygen and nutrients were collected at three stations in the southern Canada Basin during the summer 1999 cruise. We identified the cores of the surface, near-surface, potential temperature maximum waters and Arctic Bottom Water by the diagrams and vertical profiles of salinity, potential temperature, oxygen and nutrients. The historical 129Ⅰ data indicated that the surface and near-surface waters were Pacific-origin, but the waters below the potential temperature maximum core depth was Atlantic-origin. Along with the correlation of nutrient maximums and very low oxygen contents in the near-surface water, we hypothesize that, the putative organic matter was decomposed to inorganic nutrients; and the Pacific water was mixed with the Atlantic water in the transition zone. The idea of the regeneration-mixture process agrees with the historical observations of no apparent seasonal changes, the smooth nutrient profiles, the lowest saturation of CaCO3 above 400 m, low rate of CFC-11 ventilation and 3H-3He ages of 8~18 a around the nutrient maximum depths.

  5. Provenance and paleogeography of the Devonian Durazno Group, southern Parana Basin in Uruguay

    Science.gov (United States)

    Uriz, N. J.; Cingolani, C. A.; Basei, M. A. S.; Blanco, G.; Abre, P.; Portillo, N. S.; Siccardi, A.

    2016-03-01

    A succession of Devonian cover rocks occurs in outcrop and in the subsurface of central-northern Uruguay where they were deposited in an intracratonic basin. This Durazno Group comprises three distinct stratigraphic units, namely the Cerrezuelo, Cordobés and La Paloma formations. The Durazno Group does not exceed 300 m of average thickness and preserves a transgressive-regressive cycle within a shallow-marine siliciclastic shelf platform, and is characterized by an assemblage of invertebrate fossils of Malvinokaffric affinity especially within the Lower Devonian Cordobés shales. The sedimentary provenance of the Durazno Group was determined using petrography, geochemistry, and morphological studies of detrital zircons as well as their U-Pb ages. Sandstone petrography of Cerrezuelo and La Paloma sequences shows that they have a dominantly quartz-feldspathic composition with a minor contribution of other minerals. Whole-rock geochemical data indicate that alteration was strong in each of the three formations studied; chondritic-normalized REE patterns essentially parallel to PAAS, the presence of a negative Eu-anomaly, and Th/Sc and La/Hf ratios point to an average source composition similar to UCC or slightly more felsic. Within the Cerrezuelo Formation, recycling of older volcano-metasedimentary sources is interpreted from Zr/Sc ratios and high Hf, Zr, and REE concentrations. U-Pb detrital zircon age populations of the Cerrezuelo and La Paloma formations indicate that the principal source terranes are of Neoproterozoic age, but include also minor populations derived from Mesoproterozoic and Archean-Paleoproterozoic rocks. A provenance from the Cuchilla Dionisio-Dom Feliciano, Nico Pérez and Piedra Alta terranes of Uruguay and southern Brazil is likely. This study establishes an intracratonic extensional tectonic setting during Durazno time. Considering provenance age sources, regional paleocurrent distributions and the established orogenic history recorded in SW

  6. Urbanization dramatically altered the water balances of a paddy field dominated basin in Southern China

    Directory of Open Access Journals (Sweden)

    L. Hao

    2015-02-01

    Full Text Available Rice paddy fields provide important ecosystem services (e.g., food production, water retention, carbon sequestration to a large population globally. However, these benefits are declining as a result of rapid environmental and socioeconomic transformations characterized by population growth, urbanization, and climate change in many Asian countries. This case study examined the responses of streamflow and watershed water balances to the decline of rice paddy fields due to urbanization in the Qinhuai River Basin in southern China where massive industrialization has occurred in the region during the past three decades. We found that streamflow increased by 58% and evapotranspiration (ET decreased by 23% during 1986–2013 as a result of an increase in urban areas of three folds and reduction of rice paddy field by 27%. Both highflows and lowflows increased significantly by about 28% from 2002 to 2013. The increases in streamflow were consistent with the decreases in ET and leaf area index monitored by independent remote sensing MODIS data. The reduction in ET and increase in streamflow was attributed to the large cropland conversion that overwhelmed the effects of regional climate warming and climate variability. Converting traditional rice paddy fields to urban use dramatically altered land surface conditions from a water-dominated to a human-dominated landscape, and thus was considered as one of the extreme types of contemporary hydrologic disturbances. The ongoing large-scale urbanization in the rice paddy-dominated regions in the humid southern China, and East Asia, will likely elevate stormflow volume, aggravate flood risks, and intensify urban heat island effects. Understanding the linkage between land use change and changes in hydrological processes is essential for better management of urbanizing watersheds.

  7. Urbanization dramatically altered the water balances of a paddy field dominated basin in Southern China

    Science.gov (United States)

    Hao, L.; Sun, G.; Liu, Y.; Wan, J.; Qin, M.; Qian, H.; Liu, C.; John, R.; Fan, P.; Chen, J.

    2015-02-01

    Rice paddy fields provide important ecosystem services (e.g., food production, water retention, carbon sequestration) to a large population globally. However, these benefits are declining as a result of rapid environmental and socioeconomic transformations characterized by population growth, urbanization, and climate change in many Asian countries. This case study examined the responses of streamflow and watershed water balances to the decline of rice paddy fields due to urbanization in the Qinhuai River Basin in southern China where massive industrialization has occurred in the region during the past three decades. We found that streamflow increased by 58% and evapotranspiration (ET) decreased by 23% during 1986-2013 as a result of an increase in urban areas of three folds and reduction of rice paddy field by 27%. Both highflows and lowflows increased significantly by about 28% from 2002 to 2013. The increases in streamflow were consistent with the decreases in ET and leaf area index monitored by independent remote sensing MODIS data. The reduction in ET and increase in streamflow was attributed to the large cropland conversion that overwhelmed the effects of regional climate warming and climate variability. Converting traditional rice paddy fields to urban use dramatically altered land surface conditions from a water-dominated to a human-dominated landscape, and thus was considered as one of the extreme types of contemporary hydrologic disturbances. The ongoing large-scale urbanization in the rice paddy-dominated regions in the humid southern China, and East Asia, will likely elevate stormflow volume, aggravate flood risks, and intensify urban heat island effects. Understanding the linkage between land use change and changes in hydrological processes is essential for better management of urbanizing watersheds.

  8. Natural gas qualities in the Southern Permian basin; Die Erdgasqualitaeten im suedlichen Permbecken

    Energy Technology Data Exchange (ETDEWEB)

    Gerling, P.; Kockel, F. [BGR, Hannover (Germany); Lokhorst, A.; Geluk, M.C. [TNO, Haarlem (Netherlands); Nicholson, R.A. [British Geological Survey, Nottingham (United Kingdom); Laier, T. [Danmarks og Groenlands Geologiske Undersoegelse, Kopenhagen (Denmark); Pokorski, J. [Panstwowy Instytut Geologiczny, Warsaw (Poland)

    1998-12-31

    There is a substantial amount of molecular and isotopic gas data in the literature but mostly in the archives of companies and geological services. As the geological services of most European countries traditionally contain (confidential and non-confidential) data on geology and resources these institutions from Great Britain, the Netherlands, Denmark, Poland and Germany decided to compile molecular and isotopic natural gas data from the area of the Southern European Permian basin. The partially EU-subsidised project was carried out between 1994 and 1997 (LOKHORST ed. 1998) The atlas is based on existing data and also on newly determined molecular and isotopic gas parameters. Ring analyses of national and international standard gases ensure the quality and comparability of the data thus obtained. The aim of the ``stocktaking`` of natural gas was to describe the gas qualities from the Southern North Sea in the West to the Eastern borders of Poland, to characterise them genetically and to relate the to the geological environment. (orig.) [Deutsch] Ein substantieller Anteil von molekularen und isotopischen Gasdaten existiert, teilweise in der Literatur, vor allem aber in den Archiven der Firmen und der geologischen Dienste. Da die geologischen Dienste der meisten europaeischen Laender traditionell (oeffentliche und vertrauliche) Daten ueber die Geologie und Rohstoffe vorhalten, haben sich diese Institutionen aus Grossbritanien, den Niederlanden, Daenemark, Polen und Deutschlands entschlossen, molekulare und isotopische Erdgasdaten aus dem Bereich des suedlichen europaeischen Permbeckens zu kompilieren. Das partiell von der EU gefoerderte Projekt wurde in den Jahren 1994 bis 1997 durchgefuehrt (LOKHORST ed. 1998). Ausser auf bereits vorhandenen Daten beruht der Atlas auf etwa 200 Neu-Bestimmungen molekularer und isotopischer Gasparameter. Ringanalysen nationaler und internationeler Standardgase gewaehrleisteten die Qualitaet und die Vergleichbarkeit der gewonnenen

  9. COCORP profiling across the Southern Oklahoma aulacogen: Overthrusting of the Wichita Mountains and compression within the Anadarko Basin

    Science.gov (United States)

    Brewer, J. A.; Good, R.; Oliver, J. E.; Brown, L. D.; Kaufman, S.

    1983-02-01

    COCORP (Consortium for Continental Reflection Profiling) deep reflection profiles recorded across the Wichita Mountains and Anadarko Basin suggest that significant crustal shortening occurred in the final stages of the evolution of the Southern Oklahoma aulacogen. The crystalline rocks of the Wichita Mountains were thrust in Pennsylvanian time northeastward over sedimentary rocks of the Anadarko Basin along a series of faults with moderate (average 30° to 40°) and southwesterly dips. These faults can be traced possibly as deep as 20 to 24 km. Listric thrust faults and hanging-wall anticlines developed in the sedimentary rocks of the basin. These features contrast with conventional interpretations of Pennsylvanian structures as the result of predominantly vertical movements along high-angle faults, and they suggest that Pennsylvanian downwarping of the Anadarko Basin was at least partially due to thrust loading. Truncations of reflections from Cambrian-Ordovician rocks in the deepest part of the basin suggest normal faulting, which would support ideas of an early extensional stage in the aulacogen cycle. The distinctive Precambrian layering seen on earlier COCORP data recorded south of the Wichita Mountains cannot be recognized under the Anadarko Basin, and the Proterozoic basin containing that layering may have been bounded on its north side by a Precambrian fault. This inferred fault was probably twice reactivated during formation of the Southern Oklahoma aulacogen—once during late Precambrian(?)-Early Cambrian extension, and again during Pennsylvanian compression. The popular view that aulacogens originated from radial rifting of updomed, homogeneous continental crust is probably too simplified, and a more important constraint on their location and development may be the nature of pre-existing lines of weakness. *Present address: Department of Earth Sciences, Cambridge University, Cambridge CB3 OEZ, England

  10. Cross-basin heterogeneity in lanternfish (family Myctophidae) assemblages and isotopic niches (δ13C and δ15N) in the southern Tasman Sea abyssal basin

    Science.gov (United States)

    Flynn, A. J.; Kloser, R. J.

    2012-11-01

    A cross-basin (longitudinal) study of lanternfishes in the southern Tasman Sea abyssal basin during the austral winter of 2008 and 2009 found that mean biomass in the Western sector was higher than that in the Eastern sector, corresponding with cross-basin patterns in oceanographic heterogeneity and productivity. Dominant species over the abyssal basin differed from those previously recorded over the neighbouring continental slope. Vertical biomass profiles indicated diffuse night-time distributions in the Central sector and extensive diel vertical migrations in the Eastern sector. In the Western sector, macrocrustacean δ13C values were significantly higher, and δ15N significantly lower, than those in the Eastern sector. The results indicate a cross-basin difference in the primary productivity environment and 15N enrichment at the base of the foodweb. The cross-basin pattern in lanternfish δ15N values mirrored that for macrocrustaceans and was not correlated with standard length. Lanternfish δ13C values did not differ between sectors, but there were depth-wise differences, with values in the shallowest stratum (0-200 m) significantly higher than those in the deepest stratum (800-1000 m). Calculated trophic levels (TLs) of lanternfishes spanned the third trophic level and marked niche segregation was evident in the Eastern (mean TL 3.0-3.9) and Central (mean TL 2.5-3.6) sectors. Together, the results suggest that the Eastern and Western sectors are distinct sub-basin scale pelagic habitats, with implications for ecosystem modelling and future monitoring.

  11. Mytilus antiquorum J. Sowerby, 1821 and other Pliocene mussels (Mollusca, Bivalvia) from the Southern North Sea Basin

    OpenAIRE

    Vervoenen, M.; Wesselingh, F.P.; Nieulande, van, F.A.D.

    2000-01-01

    Mytilus antiquorum J. Sowerby, 1821, is recorded from the Coralline Crag Formation of East Anglia (UK) and the Lillo Formation (Oorderen, Kruisschans and Merksem members) of the Antwerp area (Belgium). The species is diagnosed on the basis of newly collected material and differentiated from modern European mussel species. The presence of M. antiquorum in the southern North Sea Basin is restricted to the Middle (Piacenzian) and early Late Pliocene (Gelasian). A possible occurrence of the speci...

  12. Selective chemical degradation of kerogen from Nenjiang Formation of the southern Songliao Basin

    Institute of Scientific and Technical Information of China (English)

    XIONG; YongQiang; WANG; YongQuan; WANG; YanMei

    2007-01-01

    A sequential selective chemical degradation has been performed on the kerogen from the Nenjiang Formation of the southern Songliao Basin by using a series of mild chemical degradations (alkaline hydrolysis, cleavage of ether-bonds and sulfur-bonds, and ruthenium tetroxide (RuO4) oxidation). Subsequently, the GC-MS analyses are carried out on different degradation products. The results show that chemical degradations can release a great number of GC/MS-determinable biomarkers from insoluble kerogen, such as, alkaline hydrolysis products mainly comprise n-alkanes, fatty acids and alkanols; thiophene compounds are predominantly ether-bound to kerogen matrix; the products from the cleavage of sulfur-sulfur and sulfur-carbon bonds in the kerogen include fatty acids, alkanols and some n-alkanes with high carbon numbers; RuO4 oxidation products are predominantly monocarboxylic acids and α,ω-dicarboxylic acids. The distributions of main degradation products indicate that organic matter in this kerogen is predominantly derived from algae and bacteria, and that small amounts of high plant-derived organic matter are possibly combined into kerogen matrix at the late stage by sulfur bonds and other means. This study will provide an important approach for further discussing sources of organic matter in source rocks and their depositional paleoenvironments.

  13. Biomonitoring recycled water in the Santa Ana River Basin in southern California.

    Science.gov (United States)

    Deng, Xin; Carney, Michael; Hinton, David E; Lyon, Stephen; Woodside, Greg; Duong, Cuong N; Kim, Sang-Don; Schlenk, Daniel

    2008-01-01

    The Santa Ana River (SAR) is the primary source of groundwater recharge for the Orange County Groundwater Basin in coastal southern California. Approximately 85% base flow in the SAR originates from wastewater treatment plants operated by three dischargers. An on-line, flow-through bioassay using Japanese medaka (Oryzias latipes) as a means of judging potential public health impacts was employed to evaluate the water quality of the surface water and shallow groundwater originating from the SAR. Three chronic (3-4.5 mo) exposures using orange-red (outbred, OR) and see-through (color mutant, ST-II) Japanese medaka as bioindicators were conducted to evaluate endocrinologic, reproductive, and morphologic endpoints. No statistically significant differences in gross morphological endpoints, mortality, gender ratios, and vitellogenin induction were observed in fish from SAR groundwater treatment compared to the group tested in solute reconstituted reverse osmosis-treated or granular activated carbon (GAC)-treated control waters. Significant differences were observed in egg reproduction and the time to hatch in SAR groundwater; however, total hatchability was not significantly lower. To evaluate the estrogenic activity of the surfacewater source of the groundwater, SAR surface water was evaluated for vitellogenin and gonadal histopathology in juvenile medaka with no effects observed. These results demonstrate that OR Japanese medaka may be a sensitive strain as an on-line monitor to predict potential impacts of water quality, but further studies are needed to elicit causative agents within the water mixture. PMID:18080901

  14. Geochemical processes controlling the groundwater quality in lower Palar river basin, southern India

    Indian Academy of Sciences (India)

    M Senthilkumar; L Elango

    2013-04-01

    Hydrogeochemical study of groundwater was carried out in a part of the lower Palar river basin, southern India to determine the geochemical processes controlling the groundwater quality. Thirty-nine groundwater samples were collected from the study area and analysed for pH, Eh, EC, Ca, Mg, Na, K, HCO3, CO3, Cl and SO4. The analysed parameters of the groundwater in the study area were found to be well within the safe range in general with respect to the Bureau of Indian Standards for drinking water except for few locations. The results of these analyses were used to identify the geochemical processes that are taking place in this region. Cation exchange and silicate weathering are the important processes controlling the major ion distribution of the study area. Mass balance reaction model NETPATH was used to assess the ion exchange processes. High concentration of Ca in groundwater of the study area is due to the release of Ca by aquifer material and adsorption of Na due to ion exchange processes. Groundwater of the study area is suitable for drinking and irrigation purposes except for few locations.

  15. Structural framework and Mesozoic Cenozoic evolution of Ponta Grossa Arch, Paraná Basin, southern Brazil

    Science.gov (United States)

    Strugale, Michael; Rostirolla, Sidnei Pires; Mancini, Fernando; Portela Filho, Carlos Vieira; Ferreira, Francisco José Fonseca; de Freitas, Rafael Corrêa

    2007-09-01

    The integration of structural analyses of outcrops, aerial photographs, satellite images, aeromagnetometric data, and digital terrain models can establish the structural framework and paleostress trends related to the evolution of Ponta Grossa Arch, one of the most important structures of the Paraná Basin in southern Brazil. In the study area, the central-northern region of Paraná State, Brazil, the arch crosses outcropping areas of the Pirambóia, Botucatu, and Serra Geral Formations (São Bento Group, Mesozoic). The Pirambóia and Botucatu Formations are composed of quartz sandstones and subordinated siltstones. The Serra Geral Formation comprises tholeiitic basalt lava flows and associated intrusive rocks. Descriptive and kinematic structural analyses reveal the imprint of two brittle deformation phases: D1, controlled by the activation of an extensional system of regional faults that represent a progressive deformation that generated discontinuous brittle structures and dike swarm emplacement along a NW-SE trend, and D2, which was controlled by a strike-slip (transtensional) deformation system, probably of Late Cretaceous-Tertiary age, responsible for important fault reactivation along dykes and deformation bands in sandstones.

  16. Features of Late Cenozoic Deepwater Sedimentation in Southern Qiongdongnan Basin,Northwestern South China Sea

    Institute of Scientific and Technical Information of China (English)

    Yuan Shengqiang; Yao Genshun; Lü Fuliang; Hu Bing; He Xiaosu; Wang Bin; Li Li

    2009-01-01

    Based on high resolution 2D and 3D seismic data acquired in recent years,using sequence stratigraphy analysis and geophysical methods,we discuss the features of Late Cenozoic deepwater sedimentation in the southern Qiongdongnan (琼东南) basin.The study area entered a bathyal slope environment in the Miocene.The channel developed in the Sanya (三亚) Formation was controlled by a fault break,and its shingled seismic characteristics represent multiple erosion and fill,which may indicate that turbidite current developed in the slope environment.The polygon faults found in mudstone of the Meishan (梅山) Formation represent the deepwater hungry sedimentary environment.The large-scale channels developed on the top of HuangUu (黄流) Formation could be the result of a big sea level drop and an increase of sediment supply.The fantastic turbidite channel developed in Late Quaternary in the slope environment has "fan-like" body and long frontal tiny avuision channel The analysis of these features suggests that the sediment supply of the study area in the post-rifting period was dominant from the Vietnam uplift in the southwest.These deepwater sedimentary features could be potential reservoirs or migration pathways for deepwater petroleum systems.

  17. Southern Great Basin seismological data report for 1981 and preliminary data analysis

    International Nuclear Information System (INIS)

    Earthquake data for the calendar year 1981 are reported for earthquakes occurring within and adjacent to the southern Great Basin seismograph network. Locations, magnitudes, and selected focal mechanisms for these events and events from prior years of network operations are presented and discussed in relation to the geologic framework of the region. These data are being collected to aid in the evaluation of the seismic hazard to a potential repository site at Yucca Mountain in the southwestern Nevada Test Site. The regional stress field orientation, as inferred from focal mechanisms, is characterized by a northwest-directed least compressive stress and a northeast-directed greatest compressive stress. We infer from this stress orientation that faults of north to northeast trend are most susceptible to slip. Faults of this orientation exist within the Yucca Mountain block, but they probably have not moved significantly in the last 500,000 years. Yucca Mountain lies within a fairly large area of relatively low level seismicity extending west to the Funeral Mountains, south of the Black Mountains and Nopah Range, and southeast to the Spring Mountains. One M 1.7 earthquake has been located in the Yucca Mountain block in about 1 year of intense monitoring. At present somewhat conflicting geologic, seismologic, and stress evidence hinder definitive conclusions about the seismic hazard at the proposed repository site. 36 references, 18 figures, 1 table

  18. Proterozoic basin in the southern Midcontinent of the United States revealed by COCORP deep seismic reflection profiling

    Science.gov (United States)

    Brewer, J. A.; Brown, L. D.; Steiner, D.; Oliver, J. E.; Kaufman, S.; Denison, R. E.

    1981-12-01

    COCORP deep crustal seismic profiles in southwestern Oklahoma show strong, persistent, continuous, and undeformed layering in the basement over an area probably very much greater than 2,500 km2. Such layering is very unusual, judging by COCORP experience with basement rocks elsewhere in the United States. The data can be interpreted as representing a Proterozoic basin filled with clastic sedimentary and felsic volcanic rocks 7 to 10 km thick, whose base lies 10 to 13 km deep. These rocks are believed, on the basis of sparse evidence from regional geology, to have been deposited or extruded about 1,200 to 1,400 m.y. ago, and some of them may now be metamorphosed. This basin lies on the south side of the Wichita Mountains, under the Paleozoic Hardeman Basin, and is similar in depth to the Paleozoic Anadarko Basin north of the mountains. The deep basement layering is truncated on the south side of the Wichita Mountains, probably by Precambrian faults in conjunction with granitic intrusions. Pennsylvanian compression probably reactivated these Precambrian trends. Extensive Precambrian basin deposits in this area were unexpected, on the basis of evidence from sparse well control, and reports of other layered basement reflections elsewhere in the southern Midcontinent suggest that Precambrian basins may be an important feature of this region. Simple models for the evolution of southwestern Oklahoma as an aulacogen must be reformulated in the light of these new data.

  19. A review of the stratigraphy and sedimentary environments of the Karoo-aged basins of Southern Africa

    Science.gov (United States)

    Smith, R. M. H.; Eriksson, P. G.; Botha, W. J.

    1993-02-01

    The Karoo Basin of South Africa was one of several contemporaneous intracratonic basins in southwestern Gondwana that became active in the Permo-Carboniferous (280 Ma) and continued to accumulate sediments until the earliest Jurassic, 100 million years later. At their maximum areal extent, during the early Permian, these basins covered some 4.5 million km 2. The present outcrop area of Karoo rocks in southern Africa is about 300 000 km 2 with a maximum thickness of some 8000 m. The economic importance of these sediments lies in the vast reserves of coal within the Ecca Group rocks of northern and eastern Transvaal and Natal, South Africa. Large reserves of sandstone-hosted uranium and molybdenum have been proven within the Beaufort Group rocks of the southern Karoo trough, although they are not mineable in the present market conditions. Palaeoenvironmental analysis of the major stratigraphic units of the Karoo succession in South Africa demonstrates the changes in depositional style caused by regional and localized tectonism within the basin. These depocentres were influenced by a progressive aridification of climate which was primarily caused by the northward drift of southwestern Gondwana out of a polar climate and accentuated by the meteoric drying effect of the surrounding land masses. Changing palaeoenvironments clearly influenced the rate and direction of vertebrate evolution in southern Gondwana as evidenced by the numerous reptile fossils, including dinosaurs, which are found in the Karoo strata of South Africa, Lesotho, Namibia and Zimbabwe. During the Late Carboniferous the southern part of Gondwana migrated over the South Pole resulting in a major ice sheet over the early Karoo basin and surrounding highlands. Glacial sedimentation in upland valleys and on the lowland shelf resulted in the Dwyka Formation at the base of the Karoo Sequence. After glaciation, an extensive shallow sea covered the gently subsiding shelf, fed by large volumes of meltwater

  20. Peru; Selected Issues Paper

    OpenAIRE

    International Monetary Fund

    2012-01-01

    This Selected Issues paper examines application of fiscal framework alternatives to the case of Peru. Although growth has been at historical highs over the last decade, Peru still has an important infrastructure gap and a quarter of its population still lives in poverty. This paper applies illustratively new modified frameworks recently developed by the IMF to the case of Peru. It takes stock of analytical considerations to resource management, and analyzes Peru’s natural resource wealth an...

  1. AN UPPER VISÉAN (ASBIAN-BRIGANTIAN AND SERPUKHOVIAN CORAL SUCCESSION AT DJEBEL OUARKZIZ (NORTHERN TINDOUF BASIN, SOUTHERN MOROCCO

    Directory of Open Access Journals (Sweden)

    SERGIO RODRÍGUEZ

    2013-03-01

    Full Text Available The Djebel Ouarkziz Formation, located in the northern part of the Tindouf Basin, in western Algeria and southern Morocco, is composed mainly of shales with interbedded limestones, dolostones and sandstones. The limestone beds are relatively thin, but are laterally persistent, and can be followed along strike for tens of kilometres. We have identified 19 limestone beds in three main sections; one logged along the road from Assa to Zag, a second in the Tinguiz-Remz Valley, 15 km to the east, and a third section 10 km west of the Assa-Zag road section. Rugose coral assemblages are recorded in most limestone beds, but the stratigraphically higher beds become more diverse However, many rugose genera and species are persistent throughout much of the succession. The oldest coral assemblages are Asbian in age and the youngest coral assemblages indicate a Serpukhovian age, as confirmed by foraminiferal biostratigraphy. The first appearance of rugose corals shows a different pattern than that in northern Moroccan basins; some common genera that first appear in the Asbian and lower Brigantian in northern Morocco and Europe, appear much later, in the upper Brigantian or Serpukhovian in the Djebel Ouarkziz. The genus Kizilia, which is rare in the Upper Viséan in northern Moroccan basins, is, however, abundant in the Tindouf Basin. Interestingly, the occurrence of the genus Lonsdaleia in the Serpukhovian from Djebel Ouarkziz poses a palaeogeographic problem because of its absence in northern Moroccan basins (except as transported elements in Serpukhovian conglomerates. Similarly, Actinocyathus in the Serpukhovian in the Tindouf Basin is not present north of the Anti-Atlas Mountains. A possible coral migration route to the Tindouf Basin may be from the northeast via the Béchar Basin in Algeria, similar to that already inferred for foraminifers and calcareous algae. 

  2. Deep Processes of Basin Evolution:A Case Study of the Southern Songliao Basin and Adjacent Area,NE China in Mesozoic-Cenozoic

    Institute of Scientific and Technical Information of China (English)

    Rihui Cheng; Dongpo Wang; Linfu Xue

    2003-01-01

    In south of the Songliao Basin and adjacent area of NE China, there are several high conductive layers in crust and upper mantle. Those layers are interpreted as detachment and rheology, which represent some features of lithosphere, asthenosphere and Moho, and related to the crust-mantle structure of the continent in the study area. The differences of the crust-mantle structures in different places in the study area reflect the differences in the movement and evolution of asthenosphere, lithosphere and crust. The differences can be summarized as follows. (1) Along the south profile of MT, the buried depth of the surface of Moho is 31 ~34 km beneath the Liaohe Basin and 35~37 km beneath the west Liaoning area. Along the north profile of MT, the buried depth of Moho is 32~33 km beneath Changtu area and 36~37 km beneath Kailu area in southern Songliao Basin. The buried depth beneath the central of the Songliao Basin is 29 km.(2) The difference of thickness of lithosphere exists in the south area and the north area of Chifeng-Kaiyuan fault. The thickness of lithosphere is about 65~120 km in the south of the fault, thickening from east to west. The top surface of asthenosphere is highly uplifted in the Liaohe Basin and the highest point is about 65 km in buried depth. The thickness of lithosphere in the north of the fault is about 60~65 km, thinner about 25 km than that in the south of the fault (West Liaoning). Deep processes such as upwelling of mantle thermal flow, extension of lithosphere, underplating, and thinning and subsidence of crust, evidenced from the crust-mantle structures were the direct forces of the basin formation in the study area during the Mesozoic-Cenozoic.

  3. Peru : Social Safety Nets in Peru

    OpenAIRE

    World Bank

    2007-01-01

    The report argues that the Peru's Social Safety Net (SSN) reform process needs to be anchored to a coherent national social safety net and poverty reduction strategy. The report suggests that the SSN interventions should be differentiated, as appropriate, between the urban and rural parts of Peru. For instance, workfare programs to deal with cyclical unemployment only make sense in urban a...

  4. Aerosol emissions from forest and grassland burnings in the southern amazon basin and central Brazil

    Science.gov (United States)

    Leslie, Alistair C. D.

    1981-03-01

    Forest and grassland clearing by means of prescribed fires in tropical areas of the world may be responsible for large inputs of fine particulates to the global atmosphere besides being a major source of trace gases. The major continents on which extensive biomass burning takes place are Africa and South America. Such agricultural practices of burning have been employed throughout man's existence, but the importance and significance of such burning relative to anthropogenic industrial emissions to the atmosphere has not until extremely recently been seriously studied. In August-September 1979 project "Brushfire 1979" took place based in Brasília, Brazil. The Air Quality Division of the National Center for Atmospheric Research made ground level and aircraft measurements of trace gases (e.g. CO 2, CO, CH 4, N 2O, H 2, CH 3Cl, COS, NO, NO 2, O 3) and Florida State University sampled ground level aerosol emissions from grass and forest burnings. Aerosols were sampled using plastic 7-stage single orifice cascade impactors and FSU type linear and circular "streakers". Long term sampling was made of regional background for total particulates (8 μmad). Short term sampling within grass or forest fires was made using impactors incorporated into portable kits containing 4 miniature 12-18 V dc Brailsford pumps and a disposable dry cell power pack. Sampling times of 5-15 min were found optimal under these conditions. Grass fires were sampled in the savannah area northeast of Brasília and forest fires in the state of Mato Grosso on the southern edge of the dryland forest of the Amazon basin. Residual ash samples were collected. All of the samples were analyzed at Florida State University using PIXE for 15-20 elements including Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Pb and Sr. Computer reduction of the X-ray spectra was made using the "HEXB" program. One of the prominent features found was the large flux of small particles (containing P and S may be

  5. Urbanization dramatically altered the water balances of a paddy field-dominated basin in southern China

    Science.gov (United States)

    Hao, L.; Sun, G.; Liu, Y.; Wan, J.; Qin, M.; Qian, H.; Liu, C.; Zheng, J.; John, R.; Fan, P.; Chen, J.

    2015-07-01

    Rice paddy fields provide important ecosystem services (e.g., food production, water retention, carbon sequestration) to a large population globally. However, these benefits are diminishing as a result of rapid environmental and socioeconomic transformations, characterized by population growth, urbanization, and climate change in many Asian countries. This case study examined the responses of stream flow and watershed water balances to the decline of rice paddy fields due to urbanization in the Qinhuai River basin in southern China, where massive industrialization has occurred during the past 3 decades. We found that stream flow increased by 58 % and evapotranspiration (ET) decreased by 23 % during 1986-2013 as a result of a three-fold increase in urban areas and a reduction of rice paddy fields by 27 %. Both high flows and low flows increased significantly by about 28 % from 2002 to 2013. The increases in stream flow were consistent with the decreases in ET and leaf area index monitored by independent remote sensing MODIS (Moderate Resolution Imaging Spectroradiometer) data. Attribution analysis, based on two empirical models, indicated that land-use/land-cover change contributed about 82-108 % of the observed increase in stream flow from 353 ± 287 mm yr-1 during 1986-2002 to 556 ± 145 during 2003-2013. We concluded that the reduction in ET was largely attributed to the conversion of cropland to urban use. The effects of land-use change overwhelmed the effects of regional climate warming and climate variability. Converting traditional rice paddy fields to urban use dramatically altered land surface conditions from an artificial wetland-dominated landscape to an urban land-use- dominated one, and thus was considered an extreme type of contemporary hydrologic disturbance. The ongoing large-scale urbanization of the rice paddy-dominated regions, in humid southern China and East Asia, will likely elevate storm-flow volume, aggravate flood risks, and intensify urban

  6. Uncovering the diversity in the Amazophrynella minuta complex: integrative taxonomy reveals a new species of Amazophrynella (Anura, Bufonidae) from southern Peru

    Science.gov (United States)

    Rojas, Rommel R.; Chaparro, Juan C.; Carvalho, Vinícius Tadeu De; Ávila, Robson W.; Farias, Izeni Pires; Hrbek, Tomas; Gordo, Marcelo

    2016-01-01

    Abstract A new species of the genus Amazophrynella (Anura, Bufonidae) is described from the departments of Madre de Dios, Cusco and Junin in Peru. An integrative taxonomy approach is used. A morphological diagnosis, morphometrics comparisons, description of the advertisement call, and the phylogenetic relationships of the new species are provided. Amazophrynella javierbustamantei sp. n. differs from other species of Amazophrynella by: intermediate body-size (snout-vent length 14.9 mm in males, n = 26 and 19.6 mm in females, n = 20), tuberculate skin texture of body, greatest hand length of the Amazophrynella spp. (3.6 mm in males, n = 26 and 4.6 mm in females, n = 20), venter coloration yellowish, tiny rounded black points covering the venter, and thirteen molecular autapomorphies in the 16S RNA gene. Its distribution varies from 215 to 708 m a.s.l. This discovery highlights the importance of the remnant forest in preserving the biodiversity in Peru, and increase in seven the species formally described in the genus Amazophrynella. PMID:27047239

  7. What do Great Subduction Earthquakes tell us About Continental Deformation of the Upper Plate in the Central Andes Forearc? Insights From Seismotectonics, Continental Deformation and Coulomb Modelisation Along Southern Peru Margin

    Science.gov (United States)

    Audin, L.; Perfettini, H.; Tavera, H.

    2007-05-01

    Subduction of the Nazca plate beneath the Peruvian margin has produced numerous megathrust earthquakes during the last century and still constitutes mature seismic gaps in some places such as in between Ilo (Peru) and Arica (Chile). The rupture zones of the 1604, 1784 and 1868 southern Peru events were partially reactivated by the Arequipa 2001 (Mw = 8.5) seismic event, whose rupture zone was about 350km-long and stopped its propagation towards the south on Ilo Peninsula. Just after the occurrence of 2001 event, some reactivation of continental fault systems are identified and monitored thanks to the Peruvian seismic network and describe continental deformation processes occurring perpendicularly to the trench or parallel to the trench, traducing the continental plate response to major subduction earthquakes and some partitioning of the deformation. The Chololo and associated ( perpendicular to the trench) fault systems define some 80-km-long margin crustal blocks and the major one coincides with the 2001 earthquake southern limit of the rupture zone as it propagated to the south. These blocks are made from Late Jurassic and Cretaceous plutonic rocks from the Coastal Batholith; these are outcropping in some places and are evidenced by the aeromagnetic mapping elsewhere around the area. Northward along the subduction zone, another boundary between two rupture zones of major subduction earthquake was reactivated recently, perpendicularly to the trench, by the seismic crisis of October 2006, M=6.4, near Lima, right at the southern end of the rupture zone of the 1974 event (Mw=8.1).Those boundaries corresponding to discontinuities (lithospheric fault systems) in the upper plate, trending nearly perpendicular to the trench, act as earthquake barriers during rupture of large seismic events. Additionally occurred on 20 of November 2006 another seismic event (Mw=5.6 Neic, Ml=5.3) in Tacna region, showing a reverse focal mechanism compatible with the trend of the Sama

  8. Coontail fluorite rhythmites of southern Illinois: evidence for episodic basin dewatering

    Energy Technology Data Exchange (ETDEWEB)

    Cowan, C.A.; Kelly, W.C.; Wilkinson, B.H.

    1985-01-01

    Stratiform coontail ore of the Cave-in-Rock fluorite district, southern Illinois, display conspicuous, rhythmic banded textures similar to those reported in many MVT deposits throughout the world (e.g., east Tennessee, USA; Silesian-Cracow Region, Poland; and northern Baffin Island, Canada). Banding is expressed by the rhythmic alteration of two types of layers: detrital layers of fluorite mottled with particulate gangue dolomite and quartz, and layers of clear, crystalline fluorspar. Both are now composed principally of fluorite but differ in color, fabric and outline. In the past, this rhythmic banding has generally been attributed to fine-scale replacement of a primary host rock stratification or to cyclic replacement of host carbonates by a fluid of oscillating chemistry. Detailed megascopic and microscopic studies of these ores and their carbonate host real that ore bands were not derived by fine-scale in situ limestone replacement. Detrital bands contain hydraulically transported, sorted and graded, allochthonous debris derived by dissolution and disaggregation of host limestone and overlying shale. The banded fabric thus represents a cyclic interplay of chemical and hydraulic processes active during hydrothermal ore mineralization. Coontail ore bodies evidently formed in a hydrothermal spelean system, whose laterally sinuous trace reflects localization of hydrothermal activity where feeder faults intersected relatively impermeable roof-rock shales. The banded nature of these ores testifies to the ability of Mississippi Valley-type hydrothermal solutions to both create and fill their own open spaces. Moreover, the rhythmic nature of coontail ores suggests a prolonged and pulsating mineralization best explained by episodic dewatering of the Illinois Basin.

  9. Late quaternary sea bottom conditions in the southern Panama basin, Eastern Equatorial Pacific

    Science.gov (United States)

    Patarroyo, German D.; Martínez, José I.

    2015-11-01

    A paleoceanographic reconstruction of the southern Panama Basin for the last 23.000 years, based on the benthic foraminiferal analysis from the deep sea core ME0005A-24JC (0.01°N, 86.28°W, water depth 2941) is presented. Cluster and SHEBI (SHE Analysis for Biozone Identification) analyses performed on the benthic foraminiferal assemblages, evidence a faunal turnover in the early Holocene at 14 ky BP. Between 23 and 14 ky BP, Fursenkoina rotundata, Hoeglundina elegans, Globobulimina affinis, Globobulimina pacifica, Cibicidoides wuellerstorfi and Uvigerina hispidocostata were common. Conversely, from 14 ky to the present, the assemblage is represented by Chilostomella oolina, Laticarinina pauperata, and Uvigerina proboscidea. This faunal turnover suggests significant fluctuations in oxygen content at the sea floor and the organic matter (OM) influx, which could reflect: (1) fluctuations in the surface productivity related to the equatorial divergence and, (2) OM advection caused by the dynamic of the deep sea currents. Paleoproductivity estimates and benthic foraminiferal rates depict a general trend towards lower values since the Last Glacial Maximum (LGM) with a conspicuous change at 14 ky BP. Therefore, the paleoceanographic reconstructions of the ME0005A-24JC core suggest a transition from La Niña-like conditions during the LGM to El Niño-like conditions in the recent, as previously proposed for the Eastern Equatorial Pacific. Estimates of the paleo-intensity of deep sea currents based on the relative percentage abundance of the epifaunal foraminifera Cibicidoides wuellerstorfi suggest stronger deep sea currents on the Carnegie Ridge before 14 ky BP.

  10. The location and nature of the Telemzan High Ghadames basin boundary in southern Tunisia based on gravity and magnetic anomalies

    Science.gov (United States)

    Gabtni, H.; Jallouli, C.; Mickus, K. L.; Zouari, H.; Turki, M. M.

    2006-03-01

    Gravity and magnetic data were analyzed to add constraints on the location and nature of the Telemzan-Ghadames boundary (TGB) and structure of the Ghadames basin in southern Tunisia. TGB is the boundary between the thick sedimentary cover of the intracratonic Ghadames basin to the south and the thin sedimentary cover of the Saharan platform to the north. The upward continuation of the Bouguer gravity anomalies showed that the TGB is a regional geophysical feature that may have controlled the amount of sediment being deposited both north and south of the boundary and the tectonic environment in the region since Paleozoic time. To emphasize the shorter wavelength gravity and magnetic anomalies, a series of gray scale images of the directional horizontal gradients were constructed that determined a series of previously unknown east-west-trending gravity and magnetic anomalies south of 31.6°N that correspond to lineaments seen on a Landsat 7 image and the location of the TGB. Also, an edge-enhancement analysis illustrated the same linear gravity anomalies and showed the subbasins and uplifts within the Ghadames basin had source depths of between 0.5 and 3.4 km. A north-south trending gravity model showed that the TGB is a relatively gradual feature (possibly basement stepped down by relatively low-displacement faulting) controlling the subsidence of the main Ghadames basin and confirms the edge-enhancement analysis that subbasin S3 and uplift U1 are the main structural features within the Ghadames basin. The knowledge of basement architecture of the Ghadames basin is important for future petroleum exploration within this intracratonic basin.

  11. Drought management plans and water availability in agriculture: A risk assessment model for a Southern European basin

    Directory of Open Access Journals (Sweden)

    Carlos Dionisio Pérez-Blanco

    2014-08-01

    Full Text Available The Drought Management Plans (DMPs are regulatory instruments that establish priorities among the different water uses and define more stringent constraints to access to publicly provided water during droughts, especially for non-priority uses such as agriculture. These plans have recently become widespread across EU southern basins. However, in some of these basins the plans were approved without an assessment of the potential impacts that they may have on the economic activities exposed to water restrictions. This paper develops a stochastic methodology to estimate the expected water availability in agriculture that results from the decision rules of the recently approved DMPs. The methodology is applied to the particular case of the Guadalquivir River Basin in southern Spain. Results show that if DMPs are successfully enforced, available water will satisfy in average 62.2% of current demand, and this figure may drop to 50.2% by the end of the century as a result of climate change. This is much below the minimum threshold of 90% that has been guaranteed to irrigators so far.

  12. Wari influence in southern Peru: provenance study of middle horizon pottery from the archaeological site of La Real using k0-INAA

    International Nuclear Information System (INIS)

    Fragments of archaeological pottery from a rescue excavation at the site of La Real in Arequipa, Peru, were studied by instrumental neutron activation analysis, k0 method. Analytical data were processed by multivariate statistical techniques, comparing the chemical composition of the studied samples versus the information available in our database on the chemical composition of archaeological pottery from Conchopata (Ayacucho), Cotahuasi (Arequipa), Huaro (Cusco) and Tiwanaku (Bolivia). The results obtained revealed that most of the samples were likely made locally at La Real, while others correspond to the chemical composition of the different groups considered, showing evidence of the presence of foreign pottery in the site and a small group which were not classified. (author)

  13. The Common Agricultural Policy as a driver of water quality changes: the case of the Guadalquivir River Basin (southern Spain

    Directory of Open Access Journals (Sweden)

    Gloria Salmoral

    2015-09-01

    Full Text Available Several studies have analysed the effects of European environmental policies on water quality, but no detailed retrospective analysis of the impacts of the Common Agricultural Policy (CAP reforms on observed water quality parameters has been carried out. This study evaluates the impact of the CAP and other drivers on the concentrations of nitrates and suspended solids in the Guadalquivir River Basin (southern Spain over the 1999-2009 period. The most important drivers that are degrading both water quality indicators are exports from upland areas and agricultural intensification. Water quality conditions have improved in regions where there has been abandonment and/or deintensification. The decoupling process has reduced the concentration of nitrates and suspended solids in a number of subbasins. Although agricultural production and water efficiency in the basin have improved, high erosion rates have not yet been addressed. 

  14. Efficacy of three different regimens of primaquine for the prevention of relapses of Plasmodium vivax malaria in the Amazon Basin of Peru.

    Science.gov (United States)

    Durand, Salomón; Cabezas, Cesar; Lescano, Andres G; Galvez, Mariela; Gutierrez, Sonia; Arrospide, Nancy; Alvarez, Carlos; Santolalla, Meddly L; Bacon, David J; Graf, Paul C F

    2014-07-01

    We evaluated the efficacy of three primaquine (PQ) regimes to prevent relapses with Plasmodium vivax through an open-label randomized trial in Loreto, Peru. Vivax monoinfections were treated with chloroquine for 3 days and PQ in three different regimes: 0.5 mg/kg per day for 5 days (150 mg total), 0.5 mg/kg per day for 7 days (210 mg total), or 0.25 mg/kg per day for 14 days (210 mg total). Biweekly fever assessments and bimonthly thick smears were taken for 210 days. Recurrences after 35 days were considered relapses. One hundred eighty cases were enrolled in each group; 90% of cases completed follow-up. There were no group-related differences in age, sex, or parasitemia. Relapse rates were similar in the 7- and 14-day regimes (16/156 = 10.3% and 22/162 = 13.6%, P = 0.361) and higher in the 5-day group (48/169 = 28.4%, P < 0.001 and P = 0.001, respectively). The 7-day PQ regimen used in Peru is as efficacious as the recommended 14-day regimen and superior to 5 treatment days.

  15. Endemic Venezuelan equine encephalitis in northern Peru.

    Science.gov (United States)

    Aguilar, Patricia V; Greene, Ivorlyne P; Coffey, Lark L; Medina, Gladys; Moncayo, Abelardo C; Anishchenko, Michael; Ludwig, George V; Turell, Michael J; O'Guinn, Monica L; Lee, John; Tesh, Robert B; Watts, Douglas M; Russell, Kevin L; Hice, Christine; Yanoviak, Stephen; Morrison, Amy C; Klein, Terry A; Dohm, David J; Guzman, Hilda; Travassos da Rosa, Amelia P A; Guevara, Carolina; Kochel, Tadeusz; Olson, James; Cabezas, Cesar; Weaver, Scott C

    2004-05-01

    Since Venezuelan equine encephalitis virus (VEEV) was isolated in Peru in 1942, >70 isolates have been obtained from mosquitoes, humans, and sylvatic mammals primarily in the Amazon region. To investigate genetic relationships among the Peru VEEV isolates and between the Peru isolates and other VEEV strains, a fragment of the PE2 gene was amplified and analyzed by single-stranded conformation polymorphism. Representatives of seven genotypes underwent sequencing and phylogenetic analysis. The results identified four VEE complex lineages that cocirculate in the Amazon region: subtypes ID (Panama and Colombia/Venezuela genotypes), IIIC, and a new, proposed subtype IIID, which was isolated from a febrile human, mosquitoes, and spiny rats. Both ID lineages and the IIID subtype are associated with febrile human illness. Most of the subtype ID isolates belonged to the Panama genotype, but the Colombia/Venezuela genotype, which is phylogenetically related to epizootic strains, also continues to circulate in the Amazon basin.

  16. Characterizaton of the Zarumilla aquifer - Peru, Ecuador

    International Nuclear Information System (INIS)

    In October 1998, Peru and Ecuador signed the Brasilia Agreements on Ecuadro-Peru border issues, representing the end of historical conflicts, differences and misunderstnadings. The two countries became partners after years of armed conflicts, and move forward through cooperation and integration, both facing social and aconomic challenges. In May 2001, the Special Bi-national Project Puyango-Tumbes (Peru) and the Ecuadorian Commission PREDESUR, province of El Oro, as technical institutes in charge of projects dealing with binational development, were invited to participate in the regional project RLA/8/031. The results of the first phase of the study are presented in this document. The study will be continued under the TC project RlA/8/039 - 'Characterization of the Zarumilla aquifer and monitoring of water quality in the Puyango-Tumbes basin'. (author)

  17. Thermal History of Rocks in the Shiwandashan Basin, Southern China: Evidence from Apatite Fission-Track Analysis

    Institute of Scientific and Technical Information of China (English)

    Wang Xinwei; Wang Xinwen; Ma Yongsheng

    2005-01-01

    Based on interpretations of the apatite fission-track analysis data for 10 outcrop samples and forward modeling of confined fission-track length distributions, the thermal history of rocks in the Shiwandashan basin and its adjacent area, southern China, has been qualitatively and semi-quantitatively studied. The results reflect several features of the thermal history. Firstly, all the samples have experienced temperatures higher than 60-70 ℃. Secondly, the time that the basement strata (T1b) on the northwestern side of the Shiwandashan basin were uplifted and exhumed to the unannealed upper crust (with a paleogeotemperature of below 60-70 ℃) is much earlier than the basement rocks (γ15) on the southeastern side of the basin. Thirdly, the thermal history of samples from the basin can be divided into six stages, I.e., the fast burial and heating stage (220-145 Ma), the transient cooling stage (145-135 Ma), the burial and heating stage (135-70 Ma), the rapid cooling stage (70-50 Ma), the relatively stable stage (50-20 Ma) and another rapid cooling stage (20 Ma to present).

  18. Geologic Controls of Hydrocarbon Occurrence in the Appalachian Basin in Eastern Tennessee, Southwestern Virginia, Eastern Kentucky, and Southern West Virginia

    Energy Technology Data Exchange (ETDEWEB)

    Hatcher, Robert D

    2005-11-30

    This report summarizes the accomplishments of a three-year program to investigate the geologic controls of hydrocarbon occurrence in the southern Appalachian basin in eastern Tennessee, southwestern Virginia, eastern Kentucky, and southern West Virginia. The project: (1) employed the petroleum system approach to understand the geologic controls of hydrocarbons; (2) attempted to characterize the P-T parameters driving petroleum evolution; (3) attempted to obtain more quantitative definitions of reservoir architecture and identify new traps; (4) is worked with USGS and industry partners to develop new play concepts and geophysical log standards for subsurface correlation; and (5) geochemically characterized the hydrocarbons (cooperatively with USGS). Third-year results include: All project milestones have been met and addressed. We also have disseminated this research and related information through presentations at professional meetings, convening a major workshop in August 2003, and the publication of results. Our work in geophysical log correlation in the Middle Ordovician units is bearing fruit in recognition that the criteria developed locally in Tennessee and southern Kentucky are more extendible than anticipated earlier. We have identified a major 60 mi-long structure in the western part of the Valley and Ridge thrust belt that has been successfully tested by a local independent and is now producing commercial amounts of hydrocarbons. If this structure is productive along strike, it will be one of the largest producing structures in the Appalachians. We are completing a more quantitative structural reconstruction of the Valley and Ridge and Cumberland Plateau than has been made before. This should yield major dividends in future exploration in the southern Appalachian basin. Our work in mapping, retrodeformation, and modeling of the Sevier basin is a major component of the understanding of the Ordovician petroleum system in this region. Prior to our

  19. Evidence for an important tectonostratigraphic seismic marker across Canada Basin and southern Alpha Ridge of the Arctic Ocean

    Science.gov (United States)

    Shimeld, J.; Chian, D.; Jackson, R.; Hutchinson, D. R.; Mosher, D. C.; Wade, J.; Chapman, B.

    2010-12-01

    Using a modern ice-strengthened seismic acquisition system, more than 12,000 km of high quality 16-channel, vertical incidence seismic reflection and wide-angle sonobuoy data, along with single- and multibeam bathymetric soundings and gravimetric profiles have been acquired across Canada Basin and the southern flank of Alpha Ridge. These datasets are being used to determine the crustal types, rifting processes, subsidence history, and sedimentary sequences of this poorly known region. More than a dozen regional seismostratigraphic units are identified, exceeding ~6.5 km in total sediment thickness in the south, thinning northward toward Alpha Ridge. The oldest regionally mappable unit is informally named “bisque” and is characterized by high-amplitude, continuous, parallel and subparallel internal reflections. The bisque unit averages ~600 m thick, with significant local variability. Along southern Alpha Ridge, the base of the bisque unit is marked by a prominent angular unconformity which can be traced southwards into Canada Basin before becoming obscured by thick overlying units. Though affected by faulting and compaction drape, the bisque unit appears to be concordant with the topography of the underlying acoustic basement. It is also spatially and temporally associated with large structures that are interpreted to be volcanic edifices. Most of the 129 available sonobuoy records show clear wide-angle refractions/reflections from sedimentary and upper and lower crustal layers, which can be ray-traced and velocity modeled using constraints from coincident reflection profiles. Slight ray angle dependent anisotropy is found to best describe these observed data, and is used for conversion between two-way travel time and vertical depth domains. Two distinct features are identified for the bisque layer: 1) a wide-angle reflection observed on nearly all sonobuoy data; and 2) S waves (named PsP), doubly converted at the bisque layer. P-wave refractors from bisque

  20. Preliminary seismicity and focal mechanisms for the southern Great Basin of Nevada and California: January 1992 through September 1992

    Energy Technology Data Exchange (ETDEWEB)

    Harmsen, S.C.

    1994-06-01

    The telemetered southern Great Basin seismic network (SGBSN) is operated for the Department of Energy`s Yucca Mountain Project (YMP). The US Geological Survey, Branch of Earthquake and Landslide Hazards, maintained this network until September 30, 1992, at which time all operational and analysis responsibilities were transferred to the University of Nevada at Reno Seismological Laboratory (UNRSL). This report contains preliminary earthquake and chemical explosion hypocenter listings and preliminary earthquake focal mechanism solutions for USGS/SGBSN data for the period January 1, 1992 through September 30, 1992, 15:00 UTC.

  1. Study of the hydrological functionning of the irrigated crops in the southern mediterranean basin

    Science.gov (United States)

    Khabba, Said; Jarlan, Lionel; Er-Raki, Salah; Le Page, Michel; Merlin, Olivier; Ezzahar, Jamal; Kharrou, Mohamed H.

    2015-04-01

    In southern Mediterranean region water consumption has significantly increased over the last decades, while available water resources are becoming increasingly scarce. In Morocco, irrigation is highly water demanding: it is estimated that 83% of available resources is dedicated to agriculture with efficiency lower than 50% (Plan Bleu, 2009). In the semiarid region of Tensift Al-Haouz (center of Morocco), typical of southern Mediterranean basin, crop irrigation is inevitable for growth and development. In this situation, and to preserve water resources, the rational management of water irrigation is necessary. This objective is one of the priorities of the research program SudMed (Chehbouni et al., 2008) and the Joint Mixed Laboratory TREMA (Khabba et al. 2013), installed in Marrakech since 2002 and 2011, respectively. In these two programs, the scientific approach adopted, to monitor water transfers in soil-plant-atmosphere system, is based on the synergistic use of the mathematical modeling, the satellite observations and in situ data. Thus, during the decade 2002-2012, 17 experiments on dominant crops in the region (wheat, olive, orange, sugar beet, apricot) were performed. In these experiments, the different terms of water and heat balances exchanged between land surface and atmosphere are controlled with different devices. Results showed that the water losses by evaporation can reach 28% of water inputs for the flooding irrigation site and are obviously lower (about 18-20 % on average) for the drip irrigation sites. Concerning the deep percolation, results are surprising: water losses for the drip irrigation are in the range 29-41% of water input, whereas theses losses are between 26 and 31% for flooding irrigation. Concerning the modeling component, several models ranging from the most simple (FAO-56) to the most complex (i.e. SVAT: Soil Vegetation Atmosphere Transfer) were implemented to estimate the spatio-temporal variability of ET. The results showed that

  2. Extreme precipitation and extreme streamflow in the Dongjiang River Basin in southern China

    Directory of Open Access Journals (Sweden)

    W. Wang

    2007-07-01

    Full Text Available Extreme hydro-meteorological events have become the focus of more and more studies in the last decade. Due to the complexity of the spatial pattern of changes in precipitation processes, it is still hard to establish a clear view of how precipitation has changed and how it will change in the future. In the present study, changes in extreme precipitation and streamflow processes in the Dongjiang River Basin in southern China are investigated. It was shown that little change is observed in annual extreme precipitation in terms of various indices, but some significant changes are found in the precipitation processes on a monthly basis. The result indicates that when detecting climate changes, besides annual indices, seasonal variations in extreme events should be considered as well. Despite of little change in annual extreme precipitation series, significant changes are detected in several annual extreme flood flow and low-flow series, mainly at the stations along the main channel of Dongjiang River, which are affected significantly by the operation of several major reservoirs. The result highlights the importance of evaluating the impacts of human activities in assessing the changes of extreme streamflows. In addition, three non-parametric methods that are not-commonly used by hydro-meteorology community, i.e., Kolmogorov–Smirnov test, Levene's test and quantile test, are introduced and assessed by Monte Carlo simulation in the present study to test for changes in the distribution, variance and the shift of tails of different groups of dataset. Monte Carlo simulation result shows that, while all three methods work well for detecting changes in two groups of data with large data size (e.g., over 200 points in each group and big difference in distribution parameters (e.g., over 100% increase of scale parameter in Gamma distribution, none of them are powerful enough for small data sets (e.g., less than 100 points and small distribution

  3. IRETHERM: Geophysical modeling of the southern margin of the Dublin Basin

    Science.gov (United States)

    Vozar, J.; Jones, A. G.; Llovet, J. C.; Pasquali, R.

    2014-12-01

    Multi-dimensional magnetotelluric (MT) modelling of data collected in the Newcastle area are presented in the frame of the IRETHERM project. The Newcastle area, situated on the southern margin of the Dublin Basin, exhibits elevated geothermal gradient (>30 °C/km) in the exploratory boreholes drilled by GT Energy. The MT soundings were carried out in the highly urbanized Dublin suburb and are heavily noise-contaminated and distorted due to EM noise from nearby industry and the DC tram system. Processing the "quietest" 4-hour night time subsets of data using several robust codes and the ELICIT method we obtained reliable and interpretable MT impedance and geomagnetic transfer functions at most sites. Tensor decomposition was applied at each site to ascertain if the data are suitable for 2D modelling and to determine the appropriate geoelectric strike direction. The final 2-D models underwent examination using a new stability technique, and the final two 2-D profiles with reliability estimations, expressed through conductance and resistivity, were derived. 3-D models of all MT data in the Newcastle area have also been determined. The 3-D models exhibit higher conductive structures in comparison to the 2-D models, with similarly resistive background rocks. The shallow conductive structures, to the depth of 1 km, have north-south elongation correlated with surface traces of faults, which are perpendicular to the regional Blackrock to Newcastle Fault (BNF). Deeper structures become more oriented to regional geoelectric strike similar to 2-D regional strike. The 2-D and 3-D modeling reveal that the BNF is imaged as a conductive zone to depths of 4 km and is likely highly fractured. Generally, the area south of the BNF is more resistive and compact with a horizontal conductive layer at approximately 1 km depth and with a very thin surficial sedimentary layer. In contrast, the structures north of the BNF are more heterogeneous, with deeper conductive layers (2-3 km depth

  4. Peru action simmering despite privatization delays

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-07

    After months of delays, the sale of Petroleos del Peru SA (Petroperu) was postponed earlier this year until after the elections, which saw Peru`s incumbent President Alberto Fujimori reelected. In June, Fujimori appointed Amado Yataco Minister of Energy and Mines. Yataco, also serving as president of the privatization commission Copri, said a decision on the sale of Petroperu would be made quickly, perhaps by July 28, ahead of this report`s presstime. The uncertain status of Petroperu has not, however, slowed activity in Peru`s petroleum sector. The paper first discusses privatization plans and Petroperu`s budget, then describes exploration and development activities in the supergiant Camisea gas/condensate fields in the central southern jungle. Activities in several smaller fields are briefly described.

  5. Tectonomagmatic relationship between the Sierra Madre Occidental ignimbrite flare-up and the southern Basin and Range province

    Science.gov (United States)

    Aguirre-Diaz, G. J.; Labarthe-Hernandez, G.

    2004-12-01

    The Sierra Madre Occidental (SMO) is a Mid-Tertiary, large-volume, ignimbrite province at least 1,200 km long and 200-500 km wide, extending continuously from the U.S.-Mexico border (31\\deg N) to its intersection with the Mexican Volcanic Belt (21\\deg N). Considering the average thickness of 1,000 m for the ignimbrite plateau, based on several measured sections along the province, and the average wide of the province of 300 km, a conservative estimate of the physical volume of the SMO ignimbrites is about 360,000 km3. The southern part of the Basin and Range province is in Mexico. This extensional province overlaps in space and time with the SMO ignimbrite flare-up and formed NW- to NE-trending normal faults that bound many large grabens, which are particularly long and deep in the southern SMO. Basin and Range faulting occurred between at least 32 Ma and 12 Ma with both limits probably extending until the Eocene and the Quaternary. Ignimbrite activity can be as old as 51 Ma and as young as 17-16 Ma, but most of the ignimbrite volume was erupted in the 38-23 Ma period. Thus, the ignimbrite flare-up can be defined as a period of intense explosive volcanic activity that produced enormous volumes of silicic ignimbrite sheets, which took place mainly between 38 and 23 Ma in Mexico. The ignimbrite flare-up coincided in time with peaks in Basin and Range faulting, and the ignimbrite activity apparently migrated from the east-northeast to the west-southwest, i.e., from central Chihuahua (38-27 Ma) to Durango-Tayoltita-Nazas (32-29 Ma) to Zacatecas-Tepic (24-23 Ma), finishing by 16 Ma at Jalisco-Nayarit, as deduced from the compilation of geologic works done in the SMO. It is unknown yet whether there was a west-southward migration of Basin and Range faulting and if the ignimbrite flare-up occurred episodically as peaks (38-27 Ma, 32-29 Ma, and 24-23 Ma) or was continuous. Nevertheless, by the time that the ignimbrite flare-up started, the Basin and Range extension was

  6. Extension of geographic distribution of Chrysobrycon hesperus and C. myersi (Characiformes, Characidae, Stevardiinae for several drainages flowing into the Amazon River Basin in Peru and Colombia Extensión de la distribución geográfica de Chrysobrycon hesperus y C. myersi (Characiformes, Characidae, Stevardiinae para varios drenajes fluyendo hacia la cuenca del Amazonas en Perú y Colombia

    Directory of Open Access Journals (Sweden)

    James Anyelo Vanegas-Ríos

    2013-03-01

    Full Text Available The geographic distribution of Chrysobrycon hesperus (Böhlke and C. myersi Weitzman and Menezes is extended to new localities from the upper Amazon Basin in Peru and Colombia. Chrysobrycon hesperus is recorded for the first time for the Putumayo River Basin in Colombia.Se amplía la distribución geográfica de Chrysobrycon hesperus (Böhlke y C. myersi Weitzman y Menezes para nuevas localidades de la cuenca alta del Amazonas en Perú y Colombia. Chrysobrycon hesperus se registra por primera vez para la cuenca del río Putumayo en Colombia.

  7. Basin Evolution and Exhumation of the Xigaze Forearc, Southern Tibet: Insight from Sedimentology, Stratigraphy, and Geo-Thermochronology

    Science.gov (United States)

    Orme, D. A.; Carrapa, B.; Abbey, A. L.; Kapp, P. A.; Ding, L.

    2012-12-01

    Forearc basins are important data archives for understanding continental dynamics because they preserve the tectono-erosional record of continental margins before collision. This study focuses on the Cretaceous-Eocene Xigaze forearc basin in southern Tibet, which is exposed along ~600 km of the Indus-Yarlung Suture Zone between the Indian craton to the south and the Asian Lhasa terrane to the north. From late Cretaceous to early Cenozoic time, subduction of Neo-Tethyan oceanic crust beneath the southern margin of Asia accommodated the northward motion of the Indian craton and formed the Xigaze forearc basin. Following collision with India in the early Cenozoic, the basin transitioned from predominantly marine to non-marine sedimentation and was subsequently uplifted to a mean elevation of 5000 m. How this transition occurred remains unresolved. This study's overall objective is to decipher forearc-basin and Indo-Asia continental-margin development from field sedimentology and stratigraphy, and detrital geo-thermochronology. We present new stratigraphic sections, totaling 8 km thick, from a previously unexplored ~60 km segment of the Xigaze forearc, ~50 km north-northwest of Saga. These sections are quite different from those known farther east. Sedimentary facies of mid-Cretaceous to early Eocene deposits indicate a shoaling-upward trend consistent with other ancient forearc basins (e.g., Great Valley forearc, California). Middle to late Cretaceous deposits indicate a variety of facies and depositional environments along strike in the study area. Facies include distal marine turbidites, shelf limestones, estuarine siliciclastics, and brown paleosols. In contrast, Eocene depositional environments are transitional from nearshore marine to pericontinental. Facies consist of dirty limestones, packstones, and wackestones, interbedded with terrigenous conglomerates and red-green paleosols. Eocene fauna include abundant foraminifera such as Nummulites-Discocyclina and

  8. Discriminant analysis for characterization of hydrochemistry of two mountain river basins of contrasting climates in the southern Western Ghats, India.

    Science.gov (United States)

    Thomas, Jobin; Joseph, Sabu; Thrivikramji, K P

    2015-06-01

    Discriminant analysis (DA) was performed on river hydrochemistry data for three seasons (i.e., monsoon (MON), post-monsoon (POM), and pre-monsoon (PRM)) to examine the spatio-temporal hydrochemical variability of two mountain river basins (Muthirapuzha River Basin (MRB) and Pambar River Basin (PRB)) of the southern Western Ghats, India. Although the river basins drain tropical mountainous terrain, climate and degree of anthropogenic disturbances show significant differences (i.e., humid, more disturbed MRB vs semiarid, less disturbed PRB). In MRB, TDS, Na(+), pH, Mg(2+), and K(+) are the attributes responsible for significant hydrochemical variations between the seasons, while Cl(-), TH, and Na(+) are the predictors in PRB. The temporal discriminant models imply the importance of rainfall pattern, relative contribution of groundwater toward stream discharge and farming activities in hydrochemistry between the seasons. Inclusion of hydrochemical attributes (in the temporal discriminant functions) that can be derived from both natural and anthropogenic sources suggests that ionic enrichment strongly depends on the seasons, and is mainly due to the variability in the intensity of anthropogenic activities as well as fluctuations in river discharge. In spatial discriminant models, Cl(-) is the only variable responsible for hydrochemical variations between the basins (during MON), whereas Si discriminates during POM and PRM, implying the role of atmospheric supply, anthropogenic modifications as well as intensity of weathering. In the spatial discrimination models, misclassification of hydrochemistry data between MRB and PRB can be attributed to the overlapping effect of humid climate of MRB extending toward the upstream of (semiarid) PRB. This study underscores the versatility of DA in deciphering the significance of climatic controls on hydrochemical composition of tropical mountain rivers.

  9. Estimated water use and availability in the South Coastal Drainage Basin, southern Rhode Island, 1995-99

    Science.gov (United States)

    Wild, Emily C.; Nimiroski, Mark T.

    2005-01-01

    The South Coastal Drainage Basin includes approximately 59.14 square miles in southern Rhode Island. The basin was divided into three subbasins to assess the water use and availability: the Saugatucket, Point Judith Pond, and the Southwestern Coastal Drainage subbasins. Because there is limited information on the ground-water system in this basin, the water use and availability evaluations for these subbasins were derived from delineated surface-water drainage areas. An assessment was completed to estimate water withdrawals, use, and return flow over a 5-year study period from 1995 through 1999 in the basin. During the study period, one major water supplier in the basin withdrew an average of 0.389 million gallons per day from the sand and gravel deposits. Most of the potable water is imported (about 2.152 million gallons per day) from the adjacent Pawcatuck Basin to the northwest. The estimated water withdrawals from the minor water suppliers, which are all in Charlestown, during the study period were 0.064 million gallons per day. The self-supplied domestic, industrial, commercial, and agricultural withdrawals from the basin were 0.574 million gallons per day. Water use in the basin was 2.874 million gallons per day. The average return flow in the basin was 1.190 million gallons per day, which was entirely from self-disposed water users. In this basin, wastewater from service collection areas was exported (about 1.139 million gallons per day) to the Narragansett Bay Drainage Basin for treatment and discharge. During times of little to no recharge, in the form of precipitation, the surface- and ground-water system flows are from storage primarily in the stratified sand and gravel deposits, although there is flow moving through the till deposits at a slower rate. The ground water discharging to the streams, during times of little to no precipitation, is referred to as base flow. The PART program, a computerized hydrograph-separation application, was used at the

  10. Paleocene deep-water sediments and radiolarian faunas:Implications for evolution of Yarlung-Zangbo foreland basin, southern Tibet

    Institute of Scientific and Technical Information of China (English)

    丁林

    2003-01-01

    This is the first report on the Paleocene deep-water sequences and radiolarian faunas, which are distributed along the southern side of the Yarlung-Zangbo suture zone. The Zheba group is coined to indicate these Paleocene sequences which are subsequently divided into two lithostratigraphic units based on the lithology observed in the field. The lower unit characterized by the rhythmic cherts and siliceous shales is named the Sangdanlin formation, and the upper one composed mainly of flysches is termed the Zheya formation. The radiolarian faunas from the Zheba group are assigned to the RP1-RP6 zones of the Paleocene age. The Early Paleocene ra-diolarian assemblages have the potential to be established into the low latitude radiolarian zones and to fill in the gap between the Late Cretaceous and the Late Paleocene radiolarian zonations. The radiolarian dating provides a valuable tool for the regional correlation and reconstruction of the sedimentary environment of the Neo-Tethyan Ocean. The preliminary work shows that the Paleo-cene sequences accumulated in a foreland basin resulted from the southern Asian margin loading onto the northern Indian passive continental margin. The Yarlung-Zangbo foreland basin se-quences deposited on the Indian passive continental margin also resulted in many good source- reservoir-covering assemblages for oil and gas resources.

  11. Channel change as a response to reforestation and population decline in the rural Toulourenc basin, southern French Prealps

    Science.gov (United States)

    Rubin, Z.; Janes, K.; Kondolf, G. M.; Natali, J.; Radke, J.

    2011-12-01

    As a result of demographic changes, forest cover in the southern French Prealp mountains has increased dramatically during the 20th century. Over the same time period stream morphology within these sub-Mediterranean mountain basins has also changed. At two mainstem locations and eight upstream tributary sites within the Toulourenc basin (~150 km2), we investigated the relationship between hillslope erosion processes and the evolution of stream channel morphology through analysis of historic cadastral maps (circa 1850), aerial photographs (1950-current), topographic surveys (2009-2011), dendrochronolgy of vegetative establishment on abandoned terraces, and bed material size distribution. We observed narrowing of the active channel width, channel degradation, and pavement development along the Toulourenc mainstem and upstream tributaries. On the mainstem Toulourenc, the active channel has narrowed approximately 50% (30m) between 1950 and 2011. As with other studies within the southern French Prealps, the channel modifications appear to be induced by a decrease in the coarse sediment supply as agricultural and logging lands were reforested between 1890 and 1945.

  12. Age and Growth of Brown Trout (Salmo trutta in Six Rivers of the Southern Part of Caspian Basin

    Directory of Open Access Journals (Sweden)

    Azarmidokht Kheyrandish

    2010-01-01

    Full Text Available Problem statement: Because of dramatic declines in stocks of brown trout in southern part of Caspian basin, the population's structure of brown trout (Salmo trutta in several rivers were studied to provide data for conservation programs. Approach: The structure of the populations in the six rivers of the southern part of Caspian basin including: Keliyare, Khojirood, Lar, Shirinrood, Rig cheshme and Pajimiyane, were studied. Results: Five age classes, ranged from 0+-4+ years, were determined. The most frequent age classes belong to 1+ and 2+. The length ranged from 78-305 mm and weight ranged from 3.6-390 g. Also, the condition factor ranged from 0.58-1.47. The highest and lowest length, weight and condition factor were observed in Lar and Rig cheshme, respectively. In 5 out of 6 rivers, females were dominant over males. The highest and lowest female: Male ratios were observed in Pajimiane (6.75:1 and Khojirood (0.8:1, respectively. Significant relationships were found between total length of brown trout with depth (r = 0.6, pConclusion: According to our knowledge, this is the first report of brown trout from Kelyare and Khojirood rivers. Since size of populations in studied areas are small and majority of these rivers located in low protected locations, it is essential to apply serious measures to protect these vulnerable habitats.

  13. Tectonic setting of Tummalapalle uranium deposit in Southern margin of Cuddapah Basin, Andhra Pradesh

    International Nuclear Information System (INIS)

    The theory of plate tectonics offers a fresh opportunity to interpret the evolution of sedimentary basins in terms of changing plate interactions and shifting plate margins. Late Paleoproterozoic shallow-marine sedimentary sequence of the Nallamalai Fold Belt as allochthonous body is thrusted over the successions of the Papaghni Sub-basin and Kurnool Group in the western part of the basin along Rudravaram line. Evidences of thrusting/continental collision along Rudravaram line include dissimilar provinces across a major fault/suture zone (undeformed in the west and deformed in the east), contrasting radiometric ages (1.9 Ga in the west and 1.3 to 1.6 Ga in the east), different metamorphic grades and subsurface structures. In this tectonic setting, sequence stratigraphy has been recorded in Papaghni Sub-basin, the earliest Sub-basin of Cuddapah Basin. The sequence stratigraphy is identified by the unconformities between cycles of sedimentation and these cycles of sedimentation are caused by tectonic activity. Three cycles of sedimentation were identified in Papaghni Sub-basin. Based on the available literature, it is infer red that these cycles might have been resulted by marine transgression and regression due to sea level changes probably caused by movement of crustal plates. Vast quantity of uranium derived from bordering fertile granitoids was fluxed into the basin during sedimentation. This uranium was precipitated under suitable reducing environment that prevailed during the second cycle and resulted in the formation of uranium deposit in Vempalle Formation as seen in Tummapalle. This uranium bearing horizon in Vempalle Formation hosts 'continental rift petrotectonic assemblage' of immature terrigenous sediments viz. assorted polymictic conglomerate and mixture of quartz, feldspar, apatite (collophane) and micrite. This study elucidates geological evidences to suggest that the phenomenon of plate tectonics was in operation during sedimentation of

  14. Phylogenetic status of brown trout Salmo trutta populations in five rivers from the southern Caspian Sea and two inland lake basins, Iran: a morphogenetic approach.

    Science.gov (United States)

    Hashemzadeh Segherloo, I; Farahmand, H; Abdoli, A; Bernatchez, L; Primmer, C R; Swatdipong, A; Karami, M; Khalili, B

    2012-10-01

    Interrelationships, origin and phylogenetic affinities of brown trout Salmo trutta populations from the southern Caspian Sea basin, Orumieh and Namak Lake basins in Iran were analysed from complete mtDNA control region sequences, 12 microsatellite loci and morphological characters. Among 129 specimens from six populations, seven haplotypes were observed. Based on mtDNA haplotype data, the Orumieh and southern Caspian populations did not differ significantly, but the Namak basin-Karaj population presented a unique haplotype closely related to the haplotypes of the other populations (0·1% Kimura two-parameter, K2P divergence). All Iranian haplotypes clustered as a distinct group within the Danube phylogenetic grouping, with an average K2P distance of 0·41% relative to other Danubian haplotypes. The Karaj haplotype in the Namak basin was related to a haplotype (Da26) formerly identified in the Tigris basin in Turkey, to a Salmo trutta oxianus haplotype from the Aral Sea basin, and to haplotype Da1a with two mutational steps, as well as to other Iranian haplotypes with one to two mutational steps, which may indicate a centre of origin in the Caspian basin. In contrast to results of the mtDNA analysis, more pronounced differentiation was observed among the populations studied in the morphological and microsatellite DNA data, except for the two populations from the Orumieh basin, which were similar, possibly due to anthropogenic causes.

  15. Facies architecture and stratigraphical evolution of fluvio-deltaic reservoirs of the Echinocyamus Formation (Lower Eocene) in the Block 10 area (Talara Basin, Northwestern Peru); Arquitetura de facies e evolucao estratigrafica dos reservatorios fluvio-deltaicos da Formacao Echinocyamus (Eoceno Inferior) na area do Lote 10 (Bacia de Talara, Noroeste do Peru)

    Energy Technology Data Exchange (ETDEWEB)

    Daudt, Jose Alfredo Borges [PETROBRAS Energia, Lima (Peru)], E-mail: jose.daudt@petrobras.com; Scherer, Claiton Marlon dos Santos

    2005-11-15

    This article describes the facies architecture of the Echinocyamus Formation, Lower Eocene, Talara Basin (Northwestern Peru), presenting an evolutionary stratigraphical model to the studied section. This work is a first step towards the static characterization of this unit with the objective of better understanding the internal heterogeneities of this reservoir, thus reducing uncertainties in enhanced recovery projects management. By integrating the core description (facies and facies associations) with the analysis of electrical logs (curve patterns) two different depositional domains were interpreted: a) a lower interval, deltaic prone, where parasequences and parasequence sets were developed during a high stand systems tract; and b) an upper interval, fluvial-dominated, developed during a lowstand systems tract. Later, the deltaic domain reappears as a transgressive interval over the fluvial system. Four fourth-order kinds of stratigraphical surfaces were identified; which at least potentially may be vertical flow barriers: a) parasequence or parasequence sets boundaries, b) sequence boundary that preceded the fluvial system, c) transgressive surface that marks the beginning of the deltaic transgression on the fluvial deposits and d) the maximum flooding surface. With this work, it was possible to establish a stratigraphically- controlled interpretation following a methodology that will allow these different domains to be mapped based on the electrical curves patterns, resulting in a better prediction of intervals with specific permeability and porosity characteristics. (author)

  16. The Messinian–early Pliocene stratigraphic record in the southern Bajo Segura Basin (Betic Cordillera, Spain): Implications for the Mediterranean salinity crisis

    OpenAIRE

    Soria, J. M.; Departamento Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apdo. 99, San Vicente del Raspeig, 03080 Alicante; Caracuel, J. E.; Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apdo. Correos 99, 03080 Alicante, Spain; Corbí, H.; Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apdo. Correos 99, 03080 Alicante, Spain; Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Lancis, C.; Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apdo. Correos 99, 03080 Alicante, Spain; Tent-Manclús, J. E.; Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apdo. Correos 99, 03080 Alicante, Spain; Viseras, C.; Departamento de Estratigrafía y Paleontología, Universidad de Granada, Campus de Fuente Nueva s/n, 18071 Granada, Spain; Yébenes, A.; Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apto. 99, 03080 San Vicente del Raspeig, Alicante, Spain

    2008-01-01

    The analysis of the Messinian and Pliocene stratigraphy of the southern Bajo Segura Basin (Betic Cordillera, Spain) has revealed three highstand sedimentary phases (Messinian I, Messinian II, and Pliocene) bounded by two lowstand erosional surfaces (intra-Messinian and end-Messinian unconformities). The Messinian I highstand phase is characterized by the progradation of coastal and shallow marine sandstones (La Virgen Fm) over slope and pelagic-basin marls (Torremendo Fm). After this first ph...

  17. IRETHERM: Multidimensional geophysical modeling of the southern margin of the Dublin Basin

    Science.gov (United States)

    Vozar, Jan; Jones, Alan G.; Rath, Volker; Campanya, Joan; Pasquali, Riccardo

    2015-04-01

    Multi-dimensional magnetotelluric (MT) modelling of data from the Newcastle area west of Dublin, acquired as part of the geothermal potential of Ireland (IRETHERM) project, is presented. The Newcastle area, situated on the southern margin of the Carboniferous Dublin Basin, exhibits elevated geothermal gradient (>30 ° C/km) in the exploratory boreholes drilled by GT Energy. The MT soundings were carried out in the highly urbanized Dublin suburb and are heavily noise-contaminated and distorted due to EM noise from nearby industry and the DC tram system (LUAS). We obtained reliable and interpretable MT impedance and geomagnetic transfer functions at most sites by processing the 'quietest' 4-hour night time subsets of data using several robust codes and the ELICIT method. Tensor decomposition was applied at each site to ascertain if the data are suitable for 2-D modelling and to determine the appropriate geoelectric strike direction. The obtained 2-D models underwent examination using a new stability technique, and the final two 2-D profiles with reliability estimations, expressed through conductance and resistivity, were derived. 3-D models, including all usable MT data in the Newcastle area, have also been determined with and without resistivity constrains for shallow structures from resistivity measurements in one of the boreholes (borehole NGE1). The 3-D models exhibit structures with higher conductivity in comparison to the 2-D models, with similarly resistive background rocks. The shallow conductive structures, to a depth of 1 km, have north-south elongations correlated with the surface traces of faults that are perpendicular to the regional Blackrock to Newcastle Fault (BNF). Deeper structures become more oriented to a regional geoelectric strike similar to 2-D regional strike. To obtain superior characterization of the thermal transport properties of the investigated area, we used porosity and resistivity data from borehole NGE1 to estimate relation between

  18. Comparison of two landslide inventory maps in the Cervaro basin, Puglia, Southern Italy

    Science.gov (United States)

    Mossa, S.; Cardinali, M.

    2003-04-01

    Reliable and accurate landslide inventory maps are mandatory elements of any landslide hazard or risk assessment. However, the quality, completeness, resolution and reliability of the landslide inventory maps are rarely ascertained. The lack of proper information on the quality of the inventory maps and on the reliability of the techniques used to complete the inventories may compromise the hazard or risk assessment. We present the results of a comparison of two landslide inventory maps prepared for an area of 132 km2, in the Cervaro River basin, in the NW Puglia Region of Southern Italy. The two landslide maps were prepared by different techniques. The first map (Map A) was prepared through the analysis of the literature on slope movements in the study area. Single landslides and landslide areas for which information was available where identified and sites where landslides were studied or where slope failures were reported were checked the field. Landslides were identified and mapped in the field at 1:25,000 scale. Field checks concentrated mostly in the urban areas and along the main roads. The second map (Map B) was obtained through the systematic interpretation of two sets of black and white aerial photographs, flown at a nominal scale of 1:33,000 scale, in 1954 and in 1990-91, respectively. When interpreting the two sets of aerial photographs care was taken in the identification of sites where landslides had changed (reactivations) or where new landslides had occurred. Analysis of the aerial photographs was carried out by two geomorphologists, using a discussion (or double) stereoscope. The methodology guarantees a cross check on the photo-interpretation and a more reliable landslide map. Comparison of the two landslide maps in a GIS allows for a quantitative estimate of the differences between the two inventories. Map A shows 27 landslides, for a total landslide area of 10.51 km2, 7.96% of the study area. Map B portrays 645 landslides, for a total landslide

  19. A new species of Andean frog of the genus Bryophryne from southern Peru Anura: Craugastoridae) and its phylogenetic position, with notes on the diversity of the genus.

    Science.gov (United States)

    Chaparro, Juan C; Padial, José M; Gutiérrez, Roberto C; De La Riva, Ignacio

    2015-01-01

    We describe a new species of terrestrial frog of the genus Bryophryne (Anura: Craugastoridae) from the wet puna and elfin forests of the Amazonian versant of the Andes. The new species seems to be restricted to high altitude environments at elevations between 3506-3651 m in the area now protected by Megantoni National Sanctuary and Manu National Park (Distrito de Echarate, Provincia La Convención, Departamento Cusco, Peru). The new species is characterized by lacking vomerine processes of vomers, by having tympanic annulus and tympanic membrane not evident through the skin, smooth dorsal skin with scattered warts, conspicuous dorsolateral, middorsal, and occipital folds, warty flanks, areolate skin on ventral surfaces of the body, and by lacking finger and toe fringes and basal web on feet. In life, specimens have bright and highly variable dorsal coloration that ranges from olive-green to red with variable combinations of red or orange marks (red or orange in the green form and olive-green in the red form). Molecular phylogenetic analyses of mitochondrial and nuclear DNA place the new species within the genus Bryophryne and as sister group of B. cophites. Bryophryne bustamantei, also sequenced for this study, is found as the sister group of the clade formed by B. cophites and the new species. Bryophryne is found as sister group of Psychrophrynella in maximum likelihood analyses and as the sister group of a large clade of holoadenines in parsimony analyses. The genus Bryophryne now contains nine species, all of them distributed along the Cordillera Oriental of the Peruvian Andes, southeast of the Apurimac River valley. PMID:26250261

  20. Field detection of eastern equine encephalitis virus in the Amazon Basin region of Peru using reverse transcription-polymerase chain reaction adapted for field identification of arthropod-borne pathogens.

    Science.gov (United States)

    O'Guinn, Monica L; Lee, John S; Kondig, John P; Fernandez, Roberto; Carbajal, Faustino

    2004-02-01

    In support of efforts to develop rapid diagnostic assays for use in the field, reverse transcription-polymerase chain reaction (RT-PCR) assays were developed to detect arboviruses circulating in the Amazon Basin region of Peru. Previous knowledge of arthropod/pathogen relationships allowed a focused evaluation to be conducted in November 2000 that assessed the feasibility and reliability of a mobile, rapid, field-expedient RT-PCR diagnostic system aimed at detecting eastern equine encephalitis virus (EEEV) in Culex (Melanoconion) pedroi mosquitoes. Modifications were made to a commercially available mobile molecular laboratory kit and assay procedures were tailored for use under harsh environmental conditions with field-collected and field-processed mosquitoes. From CO2 baited mosquito light traps, 3,227 Cx. (Mel.) pedroi mosquitoes were collected and sorted into 117 pools. The pools were processed and assayed in the field by RT-PCR and five of those pools were found positive for EEEV. Laboratory sequence analysis confirmed the presence of two distinct subtypes of EEEV.

  1. Jurassic–cretaceous deformational phases in the Paraná intracratonic basin, southern Brazil

    Directory of Open Access Journals (Sweden)

    A. J. Strieder

    2015-04-01

    Full Text Available This paper examines the domes and basins, regional arcs and synclines, and brittle structures of the Paraná Basin flood volcanism to characterize the deformational phases in its Jurassic to Cretaceous history. First-stage fieldwork revealed brittle structures, extensional joints, and strike-slip faults, and second-stage fieldwork investigated the connections of the brittle structures to both open folds and dome-and-basin features. Fault-slip data inversion was performed using two different techniques to distinguish local and remote stress/strain. Geometric and kinematic analyses completed the investigations of the deformation, which characterized two deformational phases for the Jurassic to Cretaceous periods in the Paraná Basin. Both developed under regional bi-directional constrictional (σ1 ≥ σ2 ≫ σ3 stress regimes that produced a number of non-cylindrical folds. A D1 deformational phase produced the N–S and E–W orthogonally oriented domes and basins. The D2 arcs and synclines are oriented towards the NW and NE and indicate a clockwise rotation (35–40° of both horizontal principal stress tensors. The extensional joints and strike-slip faults characterize the local stress field in the outer rim of the orthogonally buckled single volcanic flow, whereas the inner rim of the buckled single flow supported constriction and thus, developed the local arcuate folds.

  2. Tomographic imaging of the effects of Peruvian flat slab subduction on the Nazca slab and surrounding mantle under central and southern Peru

    Science.gov (United States)

    Scire, A. C.; Zandt, G.; Beck, S. L.; Bishop, B.; Biryol, C. B.; Wagner, L. S.; Long, M. D.; Minaya, E.; Tavera, H.

    2014-12-01

    The modern central Peruvian Andes are dominated by a laterally extensive region of flat slab subduction. The Peruvian flat slab extends for ~1500 km along the strike of the Andes, correlating with the subduction of the Nazca Ridge in the south and the theorized Inca Plateau in the north. We have used data from the CAUGHT and PULSE experiments for finite frequency teleseismic P- and S-wave tomography to image the Nazca slab in the upper mantle below 95 km depth under central Peru between 10°S and 18°S as well as the surrounding mantle. Since the slab inboard of the subducting Nazca Ridge is mostly aseismic, our results provide important constraints on the geometry of the subducting Nazca slab in this region. Our images of the Nazca slab suggest that steepening of the slab inboard of the subducting Nazca Ridge locally occurs ~100 km further inland than was indicated in previous studies. The region where we have imaged the steepening of the Nazca slab inboard of the Nazca Ridge correlates with the location of the Fitzcarrald Arch, a long wavelength upper plate topographic feature which has been suggested to be a consequence of ridge subduction. When the slab steepens inboard of the flat slab region, it does so at a very steep (~70°) angle. The transition from the Peruvian flat slab to the more normally dipping slab south of 16°S below Bolivia is characterized by an abrupt bending of the slab anomaly in the mantle in response to the shift from flat to normal subduction. The slab anomaly appears to be intact south of the Nazca Ridge with no evidence for tearing of the slab in response to the abrupt change in slab dip. A potential tear in the slab is inferred from an observed offset in the slab anomaly north of the Nazca Ridge extending subparallel to the ridge axis between 130 and 300 km depth. A high amplitude (-5-6%) slow S-wave velocity anomaly is observed below the projection of the Nazca Ridge. This anomaly appears to be laterally confined to the mantle

  3. Impact of river basin management on coastal water quality and ecosystem services: A southern Baltic estuary

    Science.gov (United States)

    Schernewski, Gerald; Hürdler, Jens; Neumann, Thomas; Stybel, Nardine; Venohr, Markus

    2010-05-01

    Eutrophication management is still a major challenge in the Baltic Sea region. Estuaries or coastal waters linked to large rivers cannot be managed independently. Nutrient loads into these coastal ecosystems depend on processes, utilisation, structure and management in the river basin. In practise this means that we need a large scale approach and integrated models and tools to analyse, assess and evaluate the effects of nutrient loads on coastal water quality as well as the efficiency of river basin management measures on surface waters and especially lagoons and estuaries. The Odra river basin, the Szczecin Lagoon and its coastal waters cover an area of about 150,000 km² and are an eutrophication hot-spot in the Baltic region. To be able to carry out large scale, spatially integrative analyses, we linked the river basin nutrient flux model MONERIS to the coastal 3D-hydrodynamic and ecosystem model ERGOM. Objectives were a) to analyse the eutrophication history in the river basin and the resulting functional changes in the coastal waters between early 1960's and today and b) to analyse the effects of an optimal nitrogen and phosphorus management scenario in the Oder/Odra river basin on coastal water quality. The models show that an optimal river basin management with reduced nutrient loads (e.g. N-load reduction of 35 %) would have positive effects on coastal water quality and algae biomass. The availability of nutrients, N/P ratios and processes like denitrification and nitrogen-fixation would show spatial and temporal changes. It would have positive consequences for ecosystems functions, like the nutrient retention capacity, as well. However, this optimal scenario is by far not sufficient to ensure a good coastal water quality according to the European Water Framework Directive. A "good" water quality in the river will not be sufficient to ensure a "good" water quality in the coastal waters. Further, nitrogen load reductions bear the risk of increased

  4. Fluvial evolution of the Rhine during the last interglacial-glacial cycle in the southern North Sea basin : A review and look forward

    NARCIS (Netherlands)

    Peeters, Jan; Busschers, Freek S.; Stouthamer, Esther

    2015-01-01

    This paper presents the current state of knowledge on the evolution and depositional history of the River Rhine in the southern part of the North Sea basin during the upper Middle and Late Pleistocene, and its response to climate change, sea-level oscillation and glacio-isostasy. The study focuses o

  5. Fluvial evolution of the Rhine during the last interglacial-glacial cycle in the southern North Sea basin: A review and look forward

    NARCIS (Netherlands)

    Peeters, J.; Busschers, F.S.; Stouthamer, E.

    2015-01-01

    This paper presents the current state of knowledge on the evolution and depositional history of the River Rhine in the southern part of the North Sea basin during the upper Middle and Late Pleistocene, and its response to climate change, sea-level oscillation and glacio-isostasy. The study focuses o

  6. Palaeotopography-governed sediment distribution—a new predictive model for the Permian Upper Rotliegend in the Dutch sector of the Southern Permian Basin

    NARCIS (Netherlands)

    Mijnlieff, H.F.; Geluk, M.

    2011-01-01

    The Southern Permian Basin (SPB) formed a large, elongated saucer-shaped inland depression extending from the UK to Poland and from Belgium to Denmark. During the Middle to early Late Permian the SPB was filled progressively by playa sediments from its centre in northwestern Germany before it was fl

  7. Polyphase tectonic evolution of the Aksu Basin, Isparta Angle (Southern Turkey)

    Science.gov (United States)

    Üner, Serkan; Özsayin, Erman; Kutluay, Alkor; Dirik, Kadir

    2015-04-01

    The Aksu Basin, within the Isparta Angle, is located to the north of the intersection of the Aegean and Cyprus arcs and has been evolving since the Middle Miocene. Correlation of: (1) kinematic analysis of fault planes that cut the basin fill, (2) the reactivation/inversion of fault planes and (3) sedimentological data indicate that the Aksu Basin has evolved by four alternating compressional and extensional tectonic phases since its formation. The first phase was NW-SE oriented compression caused by the emplacement of the Lycian Nappe units which ended in Langhian. This compressional phase that induced the formation and the initial deformation of the basin was followed by a NW-SE extensional phase. This tectonic phase prevailed between the Langhian and Messinian and was terminated by a NE-SW compressional regime known as the Aksu Phase. The neotectonic period is characterized by NE-SW extension and began in the Late Pliocene. Correlation with the existing tectonic literature shows that the order of deformational phases proposed in this study might also be valid for the entire Isparta Angle area.

  8. Lithostratigraphy, depositional history and sea level changes of the Cauvery Basin, southern India

    Directory of Open Access Journals (Sweden)

    Muthuvairvasamy Ramkumar

    2003-01-01

    Full Text Available The sedimentary sequence exposed in the erstwhile Tiruchirapalli district hosts a more or less complete geological record of the Upper Cretaceous-Tertiary period. Systematic field mapping, collation of data on the micro-meso scale lithology, sedimentary structures, petrography, faunal assemblage and facies relationships of these rocks, in the light of modern stratigraphic concepts, helped to enumerate the lithostratigraphic setup and depositional history of the basin. Spatial and temporal variations of the lithologies and revised stratigraphic units are presented in this paper. Many high frequency sea level cycles (presumably fourth or higher order which stack up to form third order sea level cycles (six in number, which in turn form part of second order cycles (two in number, including seven eustatic sea level peaks, have been recorded in this basin. Trend analysis of sea level curves indicates a gradual increase of the sea level from Barremian to Coniacian and a gradual decrease from Coniacian to Danian. Such lasting sea level trends had their influence on the sedimentation pattern and facies association. It is inferred that depositional bathymetry was maintained at a shallow-moderate level, primarily influenced by a lack of major subsidence during the depositional history of this basin. The study also revealed a prevalent simple basin filling process and dominant control by sea level changes, rather than tectonic movements over the depositional regime.

  9. Ecotoxicological assessment of the impact of residual heavy metals on soil nematodes in the Guadiamar River Basin (Southern Spain).

    Science.gov (United States)

    Sánchez-Moreno, Sara; Camargo, Julio A; Navas, Alfonso

    2006-05-01

    On 25 April 1998, as a consequence of the breaking of a dam containing the tailings of a pyrite mine, a land strip of approximately 43 km in length was covered with a layer of black sludge, containing high levels of heavy metals, along the Guadiamar River Basin (southern Spain). In this investigation we carried out an ecotoxicological assessment (field and laboratory studies) of the impact of residual heavy metals (Cu, Pb, Zn, Ni) on soil nematodes in the impacted riparian zone, two years after the huge mine spillage. Concentrations of residual heavy metals were significantly (Pimpacted sampling sectors (S-2, S-3, S-4, S-5) than at the unpolluted (reference) sampling sector (S-1). Nickel however exhibited the lowest increases at the impacted sectors. As a consequence, correlation coefficients between concentrations of heavy metals and values of ecological indices were not significant for Ni. In contrast, copper, lead and zinc exhibited significant (Pimpacted riparian zone of the Guadiamar River Basin. Cu, Pb and, to a lesser extent, Zn would be major responsible for the observed impact. PMID:16779593

  10. Decline of General Intelligence in Children Exposed to Manganese from Mining Contamination in Puyango River Basin, Southern Ecuador.

    Science.gov (United States)

    Betancourt, Óscar; Tapia, Marlene; Méndez, Ignacio

    2015-09-01

    Based on ecosystem approaches to health (Ecohealth), this study sought to identify neurobehavioral disorders in children exposed to several levels of toxic metal pollution from gold mining in the Puyango River Basin, Southern Ecuador. Ninety-three children born or living in the study area participated in the study. A neurobehavioral test battery consisting of 12 tests assessing various functions of the nervous system was applied as well as a questionnaire regarding events of exposure of children's mothers to contaminants during perinatal period. Hair samples were taken from children to determine manganese concentrations. Descriptive and inferential statistics were applied in order to examine possible relationships between exposure events, hair manganese, and neurobehavioral disorders. Having controlled co-variables such as age and educational level, it was found that children with elevated levels of hair manganese (over 2 μg/g) had poor performance in the test of general intelligence (Raven's Progressive Color Matrices Scale PCM). The Ecohealth approach helped to identify that children in the lower Puyango Basin with very elevated levels of manganese in the river water (970 µg/L) are the ones who have the highest levels of hair manganese and the worst performance in the intelligence test.

  11. Comparison of Statistical Downscaling Methods for Monthly Total Precipitation: Case Study for the Paute River Basin in Southern Ecuador

    Directory of Open Access Journals (Sweden)

    L. Campozano

    2016-01-01

    Full Text Available Downscaling improves considerably the results of General Circulation Models (GCMs. However, little information is available on the performance of downscaling methods in the Andean mountain region. The paper presents the downscaling of monthly precipitation estimates of the NCEP/NCAR reanalysis 1 applying the statistical downscaling model (SDSM, artificial neural networks (ANNs, and the least squares support vector machines (LS-SVM approach. Downscaled monthly precipitation estimates after bias and variance correction were compared to the median and variance of the 30-year observations of 5 climate stations in the Paute River basin in southern Ecuador, one of Ecuador’s main river basins. A preliminary comparison revealed that both artificial intelligence methods, ANN and LS-SVM, performed equally. Results disclosed that ANN and LS-SVM methods depict, in general, better skills in comparison to SDSM. However, in some months, SDSM estimates matched the median and variance of the observed monthly precipitation depths better. Since synoptic variables do not always present local conditions, particularly in the period going from September to December, it is recommended for future studies to refine estimates of downscaling, for example, by combining dynamic and statistical methods, or to select sets of synoptic predictors for specific months or seasons.

  12. Diversity and biogeography of bacterial assemblages in surface sediments across the San Pedro Basin, Southern California Borderlands.

    Science.gov (United States)

    Hewson, Ian; Jacobson Meyers, Myrna E; Fuhrman, Jed A

    2007-04-01

    Sediment bacteria play important roles in the biogeochemistry of ocean sediments; however, factors influencing assemblage composition have not been extensively studied. We examined extractable sediment bacterial abundance, the composition of bacterial assemblages using a high-throughput molecular fingerprinting approach, and several sediment biogeochemical parameters (organic matter content and alkaline phosphatase activity), along a 35 km transect from Point Fermin, Southern California, to Santa Catalina Island, across the approximately 900-m-deep San Pedro Basin. Automated rRNA intergenic spacer analysis (ARISA) demonstrated that in two spatially isolated shallow (approximately < 60 m, on opposite sides of the channel) sediment environments, assemblages were more similar to each other than to deeper communities. Distinct communities existed in deeper and shallower sediments, and stations within the deep basin over 2 km apart contained remarkably similar assemblage fingerprints. The relative contribution to total amplified DNA fluorescence of operational taxonomic units (OTUs) was significantly correlated to that of other OTUs in few comparisons (2.7% of total), i.e. few bacterial types were found together or apart consistently. The relative proportions within assemblages of only a few OTU were significantly correlated to measured physicochemical parameters (organic matter content and wet/dry weight ratio of sediments) or enzyme (alkaline phosphatase) activities. A low percentage of shared OTU between shallow and deep sediments, and the presence of similar, but spatially isolated assemblages suggests that bacterial OTU may be widely dispersed over scales of a few kilometres, but that environmental conditions select for particular assemblages.

  13. Pre-Variscan back-arc extension of Avalonia: The genesis of the Southern North Sea Basin

    Science.gov (United States)

    Smit, Jeroen; van Wees, Jan-Diederik; Cloetingh, Sierd

    2016-04-01

    The Devonian-Early Carboniferous was a period of intense rifting in the Avalonia microplate in between the Caledonian and the Hercynian-Alleghanian collision phases. This rifting phase created the typical horst-and-graben structure of much of East Avalonia's crust that is best known from the UK and Ireland where the horsts and the graben infill are located at or near the surface. In the Southern North Sea, the Netherlands and northwest Germany, the Late Devonian-Early Carboniferous rift structure and units are obliterated by the thick cover of Late Carboniferous-to-Recent basin fill and by the recurrent fault reactivation. Although this rifting created the basis for 350 Ma of lithospheric memory, its dynamics remains relatively unknown. Major open questions include the mode and total amount of extension as well as the age and origin of the Central Graben and the relation between structures located east and west of it. This study addresses these issues by integrating existing data from lithosphere to basin scales and a map-view restoration. We have revised the crustal map of the Thor Suture Zone. The newly defined northern margin of Avalonia and the Thor Suture Zone are key elements in the reconstruction of Devonian-Carboniferous rifting of Avalonian lithosphere. We present a revised map of Devonian-Carboniferous basin structures including the main horsts and grabens and the governing faults east of the Central Graben. Based on these maps, we present a new paleotectonic reconstruction and a novel geodynamic scenario for the Devonian- Carboniferous rifting. These findings are key for better understanding of long-lived tectonic compartmentalisation and post-rifting deformation phases.

  14. Hydrological modeling of the semi-arid Andarax river basin in southern Spain

    DEFF Research Database (Denmark)

    Andersen, Flemming Hauge; Jensen, Karsten Høgh; Sandholt, Inge;

    as this it will lead to better estimate of the groundwater recharge and hereby of the groundwater availability in the delta region.   The hydrological behaviour of the Andarax river basin is simulated by the MIKE SHE code, which is a physically based, distributed and integrated hydrological model. In the first...... scenario we only use traditional meteorological data and standard values for the vegetation characteristics. The traditional meteorological data are rather sparse for the Andarax river basin and to improve the estimation of evapotranspiration we use an energy-based two-layer SVAT model and apply remote...... sensing derived variables as input data. Specifically surface temperature, global radiation, albedo and leaf area index (LAI) are derived from remote sensing images. We compare the two model simulations and focus in particular on the temporal and spatial distribution of evapotranspiration and recharge...

  15. Structural controls on fractured coal reservoirs in the southern Appalachian Black Warrior foreland basin

    Science.gov (United States)

    Groshong, R.H., Jr.; Pashin, J.C.; McIntyre, M.R.

    2009-01-01

    Coal is a nearly impermeable rock type for which the production of fluids requires the presence of open fractures. Basin-wide controls on the fractured coal reservoirs of the Black Warrior foreland basin are demonstrated by the variability of maximum production rates from coalbed methane wells. Reservoir behavior depends on distance from the thrust front. Far from the thrust front, normal faults are barriers to fluid migration and compartmentalize the reservoirs. Close to the thrust front, rates are enhanced along some normal faults, and a new trend is developed. The two trends have the geometry of conjugate strike-slip faults with the same ??1 direction as the Appalachian fold-thrust belt and are inferred to be the result of late pure-shear deformation of the foreland. Face cleat causes significant permeability anisotropy in some shallow coal seams but does not produce a map-scale production trend. ?? 2008 Elsevier Ltd. All rights reserved.

  16. Impact of Climate Change on Groundwater Resources in the Klela Basin, Southern Mali

    OpenAIRE

    Adama Toure; Bernd Diekkrüger; Adama Mariko

    2016-01-01

    Investigations of groundwater resources in order to understand aquifer system behavior are vital to the inhabitants of the Klela Basin, Mali, because groundwater is the only permanent water resource and is used for drinking water and irrigation. Due to climate change, this vital resource is being threatened. Therefore, MODFLOW was applied in this study to simulate groundwater dynamics. The aim of this study was to evaluate the impact of climate change on groundwater resources in the Klela bas...

  17. Late Givetian ammonoids from Hassi Nebech (Tafilalt Basin, Anti-Atlas, southern Morocco)

    OpenAIRE

    Bockwinkel, J.; R. T. Becker; V. Ebbighausen

    2013-01-01

    The Hassi Nebech area of the SE Tafilalt (Tafilalt Basin, Anti-Atlas, Morocco) yielded the richest and most diverse late Givetian ammonoid fauna on a global scale. Above the distinctive regional "Lower Marker Bed" (Synpharciceras clavilobum Zone), abundant loosely collected limonitic specimens derive from hypoxic shales of the Taouzites taouzensis to Petteroceras errans zones. The ontogenetic morphometry and intraspecific variability of a total of 30 species representing five families, the Ac...

  18. Risk assessment of desertification using GIS in parts of Mond Basin, Southern Iran

    International Nuclear Information System (INIS)

    The present paper attempts to evolve a new model by considering various indicators of different types of land degradation desertification, namely water erosion, soil salinity, vegetation degradation, and lowering of ground water table. the Mond river basin, located centrally to this zone, has been selected as a test area to assess the risk and kind of desertification. For this purpose two sub basins of the Payab and Quareh Aghaj have been chosen for detailed study. The thresholds for the severity classes of indicators have been established and then the hazards map for each indicator of types of desertification has been prepared in a GIS. The risk maps of water erosion, soil salinization, lowering of water table, vegetation degradation have been produced for each of the two sub basins. It was possible to distinguish the areas under actual risk from areas under potential risk of desertification types. Also areas under potential risk are classified to subclasses with different probability level to show a statistical picture of risk in future. (Author) 3 refs.

  19. A century of oilfield operations and earthquakes in the greater Los Angeles Basin, southern California

    Science.gov (United States)

    Hauksson, Egill; Goebel, Thomas; Ampuero, Jean-Paul; Cochran, Elizabeth S.

    2015-01-01

    Most of the seismicity in the Los Angeles Basin (LA Basin) occurs at depth below the sediments and is caused by transpressional tectonics related to the big bend in the San Andreas fault. However, some of the seismicity could be associated with fluid extraction or injection in oil fields that have been in production for almost a century and cover ∼ 17% of the basin. In a recent study, first the influence of industry operations was evaluated by analyzing seismicity characteristics, including normalized seismicity rates, focal depths, and b-values, but no significant difference was found in seismicity characteristics inside and outside the oil fields. In addition, to identify possible temporal correlations, the seismicity and available monthly fluid extraction and injection volumes since 1977 were analyzed. Second, the production and deformation history of the Wilmington oil field were used to evaluate whether other oil fields are likely to experience similar surface deformation in the future. Third, the maximum earthquake magnitudes of events within the perimeters of the oil fields were analyzed to see whether they correlate with total net injected volumes, as suggested by previous studies. Similarly, maximum magnitudes were examined to see whether they exhibit an increase with net extraction volume. Overall, no obvious previously unidentified induced earthquakes were found, and the management of balanced production and injection of fluids appears to reduce the risk of induced-earthquake activity in the oil fields.

  20. 1970 Huaraz, Peru Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 1970, an earthquake-induced rock and snow avalanche on Mt. Huascaran, Peru, buried the towns of Yungay and Ranrahirca. The magnitude 7.8 earthquake killed 66,794...

  1. Two new records of Fabiana stephanii Hunz. & Barboza (Solanaceae from Arequipa and Ayacucho (Peru

    Directory of Open Access Journals (Sweden)

    Eliana Linares Perea

    2016-08-01

    Full Text Available In this work, two new records of Fabiana stephanii Hunz. & Barboza for the flora of Southern Peru are reported, including taxonomical, biogeographical and phytosociological data on this species.

  2. Geogenic arsenic and other trace elements in the shallow hydrogeologic system of Southern Poopó Basin, Bolivian Altiplano.

    Science.gov (United States)

    Ormachea Muñoz, Mauricio; Wern, Hannes; Johnsson, Fredrick; Bhattacharya, Prosun; Sracek, Ondra; Thunvik, Roger; Quintanilla, Jorge; Bundschuh, Jochen

    2013-11-15

    Environmental settings in the southern area of Lake Poopó in the Bolivian highlands, the Altiplano, have generated elevated amounts of arsenic (As) in the water. The area is characterised by a semiarid climate, slow hydrological flow and geologic formations of predominantly volcanic origin. The present study aimed at mapping the extent of the water contamination in the area and to investigate the geogenic sources and processes involved in the release of As to the groundwater. Ground- and surface-water samples were collected from 24 different sites, including drinking water wells and rivers, in the southern Poopó basin in two different field campaigns during the dry and rainy seasons. The results revealed variable levels of As in shallow drinking water wells and average concentration exceeding the WHO guidelines value. Arsenic concentrations range from below 5.2 μg/L (the detection level) to 207 μg/L and averages 72 μg/L. Additionally, high boron (B) concentrations (average 1902 μg/L), and high salinity are further serious concerns for deteriorating the groundwater quality and rendering it unsuitable for drinking. Groundwater is predominantly of the Na-Cl-HCO3 type or the Ca-Na-HCO3 type with neutral or slightly alkaline pH and oxidising character. While farmers are seriously concerned about the water scarcity, and on a few occasions about salinity, there are no concerns about As and B present at levels exceeding the WHO guidelines, and causing negative long term effects on human health. Sediment samples from two soil profiles and a river bed along with fourteen rock samples were also collected and analysed. Sequential extractions of the sediments together with the calculation of the mineral saturation indices indicate that iron oxides and hydroxides are the important secondary minerals phases which are important adsorbents for As. High pH values, and the competition of As with HCO3 and dissolved silica for the adsorption sites probably seems to be an

  3. Geogenic arsenic and other trace elements in the shallow hydrogeologic system of Southern Poopó Basin, Bolivian Altiplano

    Energy Technology Data Exchange (ETDEWEB)

    Ormachea Muñoz, Mauricio, E-mail: ormachea@kth.se [KTH – International Groundwater Arsenic Research Group, Division of Land and Water Resources Engineering, Department of Sustainable Development, Environmental Sciences and Engineering, Royal Institute of Technology (KTH), Teknikringen 76, SE-100 44 Stockholm (Sweden); Laboratorio de Hidroquímica, Instituto de Investigaciones Químicas, Universidad Mayor de San Andrés, 303, La Paz (Bolivia, Plurinational State of); Wern, Hannes; Johnsson, Fredrick; Bhattacharya, Prosun [KTH – International Groundwater Arsenic Research Group, Division of Land and Water Resources Engineering, Department of Sustainable Development, Environmental Sciences and Engineering, Royal Institute of Technology (KTH), Teknikringen 76, SE-100 44 Stockholm (Sweden); Sracek, Ondra [Department of Geology, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc (Czech Republic); Thunvik, Roger [KTH – International Groundwater Arsenic Research Group, Division of Land and Water Resources Engineering, Department of Sustainable Development, Environmental Sciences and Engineering, Royal Institute of Technology (KTH), Teknikringen 76, SE-100 44 Stockholm (Sweden); Quintanilla, Jorge [Laboratorio de Hidroquímica, Instituto de Investigaciones Químicas, Universidad Mayor de San Andrés, 303, La Paz (Bolivia, Plurinational State of); Bundschuh, Jochen [KTH – International Groundwater Arsenic Research Group, Division of Land and Water Resources Engineering, Department of Sustainable Development, Environmental Sciences and Engineering, Royal Institute of Technology (KTH), Teknikringen 76, SE-100 44 Stockholm (Sweden); Faculty of Engineering and Surveying, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia)

    2013-11-15

    Highlights: • Groundwater used as drinking water has elevated concentrations of arsenic and boron. • Sediments are potential sources of arsenic and boron in shallow groundwater. • Fe-oxides and hydroxides are important absorbents of arsenic. • Multiple geochemical processes drive mobilisation of arsenic in groundwater. -- Abstract: Environmental settings in the southern area of Lake Poopó in the Bolivian highlands, the Altiplano, have generated elevated amounts of arsenic (As) in the water. The area is characterised by a semiarid climate, slow hydrological flow and geologic formations of predominantly volcanic origin. The present study aimed at mapping the extent of the water contamination in the area and to investigate the geogenic sources and processes involved in the release of As to the groundwater. Ground- and surface-water samples were collected from 24 different sites, including drinking water wells and rivers, in the southern Poopó basin in two different field campaigns during the dry and rainy seasons. The results revealed variable levels of As in shallow drinking water wells and average concentration exceeding the WHO guidelines value. Arsenic concentrations range from below 5.2 μg/L (the detection level) to 207 μg/L and averages 72 μg/L. Additionally, high boron (B) concentrations (average 1902 μg/L), and high salinity are further serious concerns for deteriorating the groundwater quality and rendering it unsuitable for drinking. Groundwater is predominantly of the Na–Cl–HCO{sub 3} type or the Ca–Na–HCO{sub 3} type with neutral or slightly alkaline pH and oxidising character. While farmers are seriously concerned about the water scarcity, and on a few occasions about salinity, there are no concerns about As and B present at levels exceeding the WHO guidelines, and causing negative long term effects on human health. Sediment samples from two soil profiles and a river bed along with fourteen rock samples were also collected and

  4. Geogenic arsenic and other trace elements in the shallow hydrogeologic system of Southern Poopó Basin, Bolivian Altiplano

    International Nuclear Information System (INIS)

    Highlights: • Groundwater used as drinking water has elevated concentrations of arsenic and boron. • Sediments are potential sources of arsenic and boron in shallow groundwater. • Fe-oxides and hydroxides are important absorbents of arsenic. • Multiple geochemical processes drive mobilisation of arsenic in groundwater. -- Abstract: Environmental settings in the southern area of Lake Poopó in the Bolivian highlands, the Altiplano, have generated elevated amounts of arsenic (As) in the water. The area is characterised by a semiarid climate, slow hydrological flow and geologic formations of predominantly volcanic origin. The present study aimed at mapping the extent of the water contamination in the area and to investigate the geogenic sources and processes involved in the release of As to the groundwater. Ground- and surface-water samples were collected from 24 different sites, including drinking water wells and rivers, in the southern Poopó basin in two different field campaigns during the dry and rainy seasons. The results revealed variable levels of As in shallow drinking water wells and average concentration exceeding the WHO guidelines value. Arsenic concentrations range from below 5.2 μg/L (the detection level) to 207 μg/L and averages 72 μg/L. Additionally, high boron (B) concentrations (average 1902 μg/L), and high salinity are further serious concerns for deteriorating the groundwater quality and rendering it unsuitable for drinking. Groundwater is predominantly of the Na–Cl–HCO3 type or the Ca–Na–HCO3 type with neutral or slightly alkaline pH and oxidising character. While farmers are seriously concerned about the water scarcity, and on a few occasions about salinity, there are no concerns about As and B present at levels exceeding the WHO guidelines, and causing negative long term effects on human health. Sediment samples from two soil profiles and a river bed along with fourteen rock samples were also collected and analysed

  5. Integrating facies and structural analyses with subsidence history in a Jurassic-Cretaceous intraplatform basin: Outcome for paleogeography of the Panormide Southern Tethyan margin (NW Sicily, Italy)

    Science.gov (United States)

    Basilone, Luca; Sulli, Attilio; Gasparo Morticelli, Maurizio

    2016-06-01

    We illustrate the tectono-sedimentary evolution of a Jurassic-Cretaceous intraplatform basin in a fold and thrust belt present setting (Cala Rossa basin). Detailed stratigraphy and facies analysis of Upper Triassic-Eocene successions outcropping in the Palermo Mts (NW Sicily), integrated with structural analysis, restoration and basin analysis, led to recognize and describe into the intraplatform basin the proximal and distal depositional areas respect to the bordered carbonate platform sectors. Carbonate platform was characterized by a rimmed reef growing with progradational trends towards the basin, as suggested by the several reworked shallow-water materials interlayered into the deep-water succession. More, the occurrence of thick resedimented breccia levels into the deep-water succession suggests the time and the characters of synsedimentary tectonics occurred during the Late Jurassic. The study sections, involved in the building processes of the Sicilian fold and thrust belt, were restored in order to obtain the original width of the Cala Rossa basin, useful to reconstruct the original geometries and opening mechanisms of the basin. Basin analysis allowed reconstructing the subsidence history of three sectors with different paleobathymetry, evidencing the role exerted by tectonics in the evolution of the narrow Cala Rossa basin. In our interpretation, a transtensional dextral Lower Jurassic fault system, WNW-ESE (present-day) oriented, has activated a wedge shaped pull-apart basin. In the frame of the geodynamic evolution of the Southern Tethyan rifted continental margin, the Cala Rossa basin could have been affected by Jurassic transtensional faults related to the lateral westward motion of Africa relative to Europe.

  6. Peru; Selected Issues

    OpenAIRE

    International Monetary Fund

    2010-01-01

    This Selected Issues paper describes recent investment dynamics in Peru, and assesses the relationship between private investment and its fundamentals. Over the last decade, average growth in Peru exceeded 6 percent, anchored by a substantial contribution from investment. A series of structural reforms in the 1990s, growing political stability, and the implementation of a solid macroeconomic framework in the early 2000s set the stage for this investment boom. Actions were also taken to streng...

  7. Introduction to selected references on fossil fuels of the central and southern Appalachian basin: Chapter H.1 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    Science.gov (United States)

    Ruppert, Leslie F.; Lentz, Erika E.; Tewalt, Susan J.; Román Colón, Yomayra A.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    The Appalachian basin contains abundant coal and petroleum resources that have been studied and extracted for at least 150 years. In this volume, U.S. Geological Survey (USGS) scientists describe the geologic framework and geochemical character of the fossil-fuel resources of the central and southern Appalachian basin. Separate subchapters (some previously published) contain geologic cross sections; seismic profiles; burial history models; assessments of Carboniferous coalbed methane and Devonian shale gas; distribution information for oil, gas, and coal fields; data on the geochemistry of natural gas and oil; and the fossil-fuel production history of the basin. Although each chapter and subchapter includes references cited, many historical or other important references on Appalachian basin and global fossil-fuel science were omitted because they were not directly applicable to the chapters.

  8. Imaging 2D structures by the CSAMT method: application to the Pantano di S. Gregorio Magno faulted basin (Southern Italy)

    Science.gov (United States)

    Troiano, Antonio; Di Giuseppe, Maria Giulia; Petrillo, Zaccaria; Patella, Domenico

    2009-06-01

    A controlled source audiofrequency magnetotelluric (CSAMT) survey has been undertaken in the Pantano di San Gregorio Magno faulted basin, an earthquake prone area of Southern Apennines in Italy. A dataset from 11 soundings, distributed along a nearly N-S 780 m long profile, was acquired in the basin's easternmost area, where the fewest data are available as to the faulting shallow features. A preliminary skew analysis allowed a prevailing 2D nature of the dataset to be ascertained. Then, using a single-site multi-frequency approach, Dantzig's simplex algorithm was introduced for the first time to estimate the CSAMT decomposition parameters. The simplex algorithm, freely available online, proved to be fast and efficient. By this approach, the TM and TE mode field diagrams were obtained and a N35°W ± 10° 2D strike mean direction was estimated along the profile, in substantial agreement with the fault traces within the basin. A 2D inversion of the apparent resistivity and phase curves at seven almost noise-free sites distributed along the central portion of the profile was finally elaborated, reinforced by a sensitivity analysis, which allowed the best resolved portion of the model to be imaged from the first few meters of depth down to a mean depth of 300 m b.g.l. From the inverted section, the following features have been outlined: (i) a cover layer with resistivity in the range 3-30 Ω m ascribed to the Quaternary lacustrine clayey deposits filling the basin, down to an average depth of about 35 m b.g.l., underlain by a structure with resistivity over 50 Ω m up to about 600 Ω m, ascribed to the Mesozoic carbonate bedrock; (ii) a system of two normal faults within the carbonate basement, extending down to the maximum best resolved depth of the order of 300 m b.g.l.; (iii) two wedge-shaped domains separating the opposite blocks of the faults with resistivity ranging between 30 Ω m and 50 Ω m and horizontal extent of the order of some tens of metres, likely

  9. Crustal shear velocity structure in the Southern Lau Basin constrained by seafloor compliance

    Science.gov (United States)

    Zha, Yang; Webb, Spahr C.

    2016-05-01

    Seafloor morphology and crustal structure vary significantly in the Lau back-arc basin, which contains regions of island arc formation, rifting, and seafloor spreading. We analyze seafloor compliance: deformation under long period ocean wave forcing, at 30 ocean bottom seismometers to constrain crustal shear wave velocity structure along and across the Eastern Lau Spreading Center (ELSC). Velocity models obtained through Monte Carlo inversion of compliance data show systematic variation of crustal structure in the basin. Sediment thicknesses range from zero thickness at the ridge axis to 1400 m near the volcanic arc. Sediment thickness increases faster to the east than to the west of the ELSC, suggesting a more abundant source of sediment near the active arc volcanoes. Along the ELSC, upper crustal velocities increase from the south to the north where the ridge has migrated farther away from the volcanic arc front. Along the axial ELSC, compliance analysis did not detect a crustal low-velocity body, indicating less melt in the ELSC crustal accretion zone compared to the fast spreading East Pacific Rise. Average upper crust shear velocities for the older ELSC crust produced when the ridge was near the volcanic arc are 0.5-0.8 km/s slower than crust produced at the present-day northern ELSC, consistent with a more porous extrusive layer. Crust in the western Lau Basin, which although thought to have been produced through extension and rifting of old arc crust, is found to have upper crustal velocities similar to older oceanic crust produced at the ELSC.

  10. Impact of Climate Change on Groundwater Resources in the Klela Basin, Southern Mali

    Directory of Open Access Journals (Sweden)

    Adama Toure

    2016-05-01

    Full Text Available Investigations of groundwater resources in order to understand aquifer system behavior are vital to the inhabitants of the Klela Basin, Mali, because groundwater is the only permanent water resource and is used for drinking water and irrigation. Due to climate change, this vital resource is being threatened. Therefore, MODFLOW was applied in this study to simulate groundwater dynamics. The aim of this study was to evaluate the impact of climate change on groundwater resources in the Klela basin using the RCP4.5 (Representative Concentration Scenario 4.5 W/m2 climate scenario. Climatological, geological, hydrogeological, hydraulic and demographic data were collected and used as model input data. Groundwater recharge was estimated to be approximately 165.3 mm/year using the EARTH (Extended model for Aquifer Recharge and soil moisture Transport through the unsaturated Hardrock model. Recharge was then used as groundwater model input. The sandstone aquifer in the study area was simulated in steady and transient conditions. The results showed that hydraulic conductivity values varied from 1.1 to 13.9 m/day. The model was used for scenario quantification after model calibration and verification using three different piezometer data sets. The results of the simulated MODFLOW model showed a decrease in groundwater levels over time.

  11. Evolutionary relationship between marble trout of the northern and the southern Adriatic basin.

    Science.gov (United States)

    Pustovrh, G; Sušnik Bajec, S; Snoj, A

    2011-06-01

    Marble trout (Salmo marmoratus) populate two geographically separated areas in the northern and southern parts of the Adriatic Sea drainage. Although morphologically similar, each population is distinguished by a different set of unrelated mitochondrial haplotypes, suggesting that they have evolved from different ancestors. Due to a possible discordance between mitochondrial and species phylogeny, we performed phylogenetic analysis based on 22 nuclear loci. The results inferred from Maximum-likelihood and Bayesian Inference analysis revealed that northern and southern populations are closely related, forming a monophyletic group. This observation is concordant with the present marble trout classification, which considers both populations as conspecific. On the other hand, our findings are in marked contrast to those of previous mtDNA-based studies and highlight potential dangers of making phylogenetic inferences from mtDNA alone. Reasons for discordance between mtDNA and nDNA phylogeny are discussed with incomplete lineage sorting proposed as the most parsimonious explanation for mtDNA divergence in marble trout.

  12. Constraints on southern hemisphere tropical climate change during the Little Ice Age and Younger Dryas based on glacier modeling of the Quelccaya Ice Cap, Peru

    Science.gov (United States)

    Malone, Andrew G. O.; Pierrehumbert, Raymond T.; Lowell, Thomas V.; Kelly, Meredith A.; Stroup, Justin S.

    2015-10-01

    Improving the late Quaternary paleoclimate record through climate interpretations of low-latitude glacier length changes advances our understanding of past climate change events and the mechanisms for past, present, and future climate change. Paleotemperature reconstructions at low-latitude glaciers are uniquely fruitful because they can provide both site-specific information and enhanced understanding of regional-scale variations due to the structure of the tropical atmosphere. We produce Little Ice Age (LIA) and Younger Dryas (YD) paleoclimate reconstructions for the Huancané outlet glacier of the Quelccaya Ice Cap (QIC) and low-latitude southern hemisphere regional sea surface temperatures (SSTs) using a coupled ice-flow and energy balance model. We also model the effects of long-term changes in the summit temperature and precipitiation rate and the effects of interannual climate variability on the Huancané glacier length. We find temperature to be the dominant climate driver of glacier length change. Also, we find that interannual climate variability cannot adequately explain glacier advances inferred from the geomorphic record, necessitating that these features were formed during past colder climates. To constrain our LIA reconstruction, we incorporate the QIC ice core record, finding a LIA air temperature cooling at the ice cap of between ˜0.7 °C and ˜1.1 °C and ˜0.4 °C and regional SSTs cooling of ˜0.6 °C. For the YD paleoclimate reconstructions, we propose two limits on the precipitation rate, since the ice core record does not extend into the Pleistocene: 1) the precipitation rate scales with the Clausius-Clapeyron relationship (upper limit on cooling) and 2) the precipitation rate increases by 40% (lower limit on cooling), which is an increase about twice as great as the regional increases realized in GCM simulations for the period. The first limit requires ˜1.6 °C cooling in ice cap air temperatures and ˜0.9 °C cooling in SSTs, and the

  13. Differentiating Tectonic and Anthropogenic Earthquakes in the Greater Los Angeles Basin, Southern California

    Science.gov (United States)

    Hauksson, E.; Goebel, T.; Cochran, E. S.; Ampuero, J. P.

    2014-12-01

    The 2014 flurry of moderate earthquakes in the Los Angeles region raised the concern if some of this or past seismicity was of anthropogenic origin as opposed to being caused by ongoing transpressional tectonics. The Mw5.1 La Habra sequence is located near several major oil fields but the Mw4.4 Encino sequence was located away from oil fields, within the Santa Monica Mountains. The last century of seismicity in the Los Angeles area consists of numerous small and large earthquakes. Most of these earthquakes occur beneath the basin sediments and are associated with transpressional tectonics, related to the big bend in the San Andreas fault, but some could be associated with large oil fields. In particular, both the 1933 Mw6.4 Long Beach and the 1987 Mw5.9 Whittier Narrows earthquakes were spatially associated with two major oil fields, the Huntington Beach and Montebello fields. Numerous large oil fields have been in production for more than 125 years. The geographical locations of the oil fields follow major tectonic trends such as the Newport-Inglewood fault, the Whittier fault, and the thrust belt located at the north edge of the Los Angeles basin. More than 60 fields have oil wells and some of these have both disposal and fracking wells. Before fluid injection became common, Kovach (1974) documented six damaging events induced by fluid extraction from 1947 to 1961 in the Wilmington oil field. Since 1981 the waveform-relocated earthquake catalog for the Los Angeles basin is complete on the average above M2.0. We compare the spatial distribution of these events and the proximity of nearby active oil fields. We will also analyze the seismicity in the context of available monthly fluid extraction and injection volumes and search for temporal correlations. The La Habra sequence apparently correlates with temporal changes in extraction and injection volumes in the Santa Fe Springs oil field but not with activities in other oil fields within closer spatial proximity.

  14. Isotopic Assessment of Sources of Surface Water Nitrate within the Oldman River Basin, Southern Alberta, Canada

    International Nuclear Information System (INIS)

    Concentrations and isotopic compositions of NO3- from the Oldman River (OMR) and some of its tributaries (Alberta, Canada) have been determined on a monthly basis since December 2000 to assess temporal and spatial variations of riverine NO3- sources within the OMR basin. For the OMR sites, NO3--N concentrations reached up to 0.34 mg L-1, δ15N-NO3- values varied between -0.3 and +13.8 per mille , and δ18O-NO3- values ranged from -10.0 to +5.7 per mille . For the tributary sites, NO3--N concentrations were as high as 8.81 mg L-1, δ15N-NO3- values varied between -2.5 and +23.4 per mille , and δ18O-NO3- values ranged from -15.2 to +3.4 per mille . Tributaries in the western, relatively pristine forested part of the watershed add predominantlyNO3- to the OMR with δ15N-NO3- values near +2 per mille indicative of soil nitrification. In contrast, tributaries in the eastern agriculturally-urban-industrially-used part of the basin contribute NO3- with δ15N-NO3- values of about +16 per mille indicative of manure and/or sewage derived NO3-. This difference in δ15N-NO3- values of tributaries was found to be independent of the season, but rather indicates a spatial change in the NO3- source, which correlates with land use changes within the OMR basin. As a consequence of tributary influx, δ15N-NO3- values in the Oldman River increased from +6 per mille in the downstream direction (W to E), although [NO3--N] increased only moderately (generally -1). This study demonstrates the usefulness of δ15N-NO3- and δ18O-NO3- values in identifying the addition of anthropogenic NO3- to riverine systems

  15. The Aquatic And Marshy Flora Of The Lotru River Basin (Southern Carpathians, Romania

    Directory of Open Access Journals (Sweden)

    Drăgulescu Constantin

    2014-10-01

    Full Text Available The present paper continues the series of floristic inventories of the main Romanian rivers in the Carpathian Mountains (from which have been published those of Mureş, Sadu, Olt, Someş, Criş, Târnave, Tisa. In this work the author lists 204 plant taxa (hydrophilic, meso-hygrophilic and hygrophilic identified by the author or by other botanists in the Lotru Valley basin. Noted for each species were life form, floral element, ecological preferences for humidity (U, temperature (T, soil reaction (R, corology and coenology. Bibliographical sources are coded with numbers (see the references at the end of the paper. The sign “!” indicates that the author has seen the plant in that locality.

  16. Seismic Data Interpretation: A Case Study of Southern Sindh Monocline, Lower Indus Basin, Pakistan

    Directory of Open Access Journals (Sweden)

    Shabeer Ahmed Abbasi

    2015-04-01

    Full Text Available The Sindh monocline in Lower Indus Basin is an important oil and gas producing area of Pakistan where a large number of oil, gas and condensate fields have been discovered from structural traps. This research involves the interpretation of stratigraphic and structural styles of Sindh Monocline using 2D (Two-Dimensional seismic reflection and well log. Four reflectors of different formations have been marked and were named as Reflector-1 as of Khadro Formation, Reflector-2 as Upper Goru Member, Reflector-3 as Lower Goru Formation and Reflector-4 as Chiltan Limestone. The average depth of Khadro Formation was marked at 449.0m, Upper Goru Member at 968m, Lower Goru Formation at 1938m and Chiltan Limestone at 2943m. Faults were marked on seismic sections which collectively form horsts and grabens which is the evidence of extensional tectonic in the area. Seismic interpretation was carried out through window based Kingdom Software

  17. Sod-podzolic soils with a complex organic profile of the southern Vyatka River basin

    Science.gov (United States)

    Prokashev, A. M.; Soboleva, E. S.; Chepurnov, R. R.; Matushkin, A. S.; Ohorzin, N. D.; Borodaty, I. L.; Zhuikova, I. A.; Alalykina, I. Y.; Russkikh, G. A.; Pupysheva, S. A.; Mokrushin, S. L.; Vartan, I. A.

    2016-08-01

    The article is devoted to the morphology and substantive properties of the sod- podzolic soils with a complex organic profile having the second humus horizons and found on the southern right bank of the lower Vyatka River. The research results of the mineral and organic phases are the evidence of the relict origin of the second humus horizon as well as the evidence of profile polygenicity of the given soils. They went through two fundamentally different pedogenesis stages during the postglacial period: 1) the developmental accumulative evolution stage in the first half of the Holocene and 2) the accumulative-eluvial stage of erasing evolution including the elements of inheriting evolution in the second half of the Holocene. Keywords: granulometric composition, fractional and group composition, humus age, genesis, soil evolution

  18. Peru v. Yale: A Battle Rages over Machu Picchu

    Science.gov (United States)

    Glenn, David

    2009-01-01

    In early 1916, the legendary Yale University archaeologist Hiram Bingham III completed his third and final expedition in southern Peru. He shipped home 74 boxes of artifacts from Machu Picchu, a spectacular site in the Andes that is believed to have been the last major settlement of the Inca empire. Those boxes were supposed to be on temporary…

  19. Andean shrublands of Moquegua, South Peru: Prepuna plant communities

    NARCIS (Netherlands)

    Montesinos, D.B.; Cleef, A.M.; Sykora, K.V.

    2012-01-01

    A syntaxonomic overview of shrubland vegetation in the southern Andean regions of Peru is presented. For each plant community, information is given on physiognomy, floristic diversity, ecology and geographical distribution. The shrub vegetation on the slopes of the upper Tambo river valley includes

  20. A 38,000-year record of floods and debris flows in the Ilo region of southern Peru and its relation to El Niño events and great earthquakes

    Science.gov (United States)

    Keefer, David K.; Moseley, Michael E.; DeFrance, Susan D.

    2003-01-01

    Previous work throughout the Ilo region of south coastal Peru has documented the existence of flood and debris-flow deposits produced by two El Niño events evidently much more severe than any in recent history. These two events have been dated to ca. AD 1300–1400 and AD 1607–08. The Late Pleistocene to Holocene record of older sedimentary deposits in this region is dominated by flood and debris-flow deposits of similar scale. These older deposits have been described and dated from three coastal, alluvial-fan sites. These deposits, which are as old as 38 200 years, are dominated by massive debris-flow deposits, several tens of cm thick, typically composed of cobble- and boulder-sized clasts in a matrix of silty sand, with characteristics indicating generation by heavy rainfall in an arid environment. Twenty-two radiocarbon dates and a single infrared-stimulated luminescence date show that particularly severe El Niño events occurred throughout the Late Pleistocene and two of three divisions of the Holocene with significantly different frequencies. The period of greatest activity was during the Early Holocene when at least six such events took place during a period of ca. 3600 years, beginning near the end of the Younger Dryas ca. 12 000 years ago. One of these events produced a debris flow that may have caused abandonment of the Paleo-Indian site at Quebrada Tacahuay, one of the oldest on the Andean coast. No severe events took place during the Middle Holocene between ca. 8400 and 5300 years ago, when a wide variety of other paleoclimate proxy records indicate that the El Niño–Southern Oscillation regime was particularly weak. Since ca. 5300 years ago, four of these severe events have taken place. The Late Pleistocene sequence is constrained by only two dates, which indicate that at least ten severe events took place between ca. 38 200 and 12 900 years ago. Mechanisms probably responsible for generating these large-scale deposits include: (1)

  1. Possible solar forcing of climate variability in the past 4000 years inferred from a proxy record at the southern margin of Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    ZHONG Wei; WANG Liguo; Tyip·Tashpolat; XIONG Heigang; SHU Qiang

    2004-01-01

    A ca. 4000a decadal-resolution climate proxy record of the mean grain-size from a lake (or mash) sediment at the southern margin of the Tarim Basin, correlates visually with the atmospheric 14C record from tree ring (residual △14C, solar proxy) and the GISP2 ice core δ18O record (temperature proxy). In general, △14C maxima (solar minima) are coincident with cold (wet) periods in the study area and cold periods in the Greenland ice core. Power spectrum analysis revealed statistically significant periodicities of 196a, 121a,97a, 62a, 45a and 33-30a, which are similar to those principal solar-oscillation periods as inferred from the atmospheric radiocarbon and other proxy records. Possible solar forcing is addressed to be the main driving forcing of climate change in the southern margin of Tarim Basin.

  2. Species composition and phytosociology of xerophytic plant communitiesSouth Peru after extreme rainfall in South Peru

    NARCIS (Netherlands)

    D.B. Montesinos-Tubée; K.V. Sýkora; V. Quipuscoa-Silvestre; A.M. Cleef

    2015-01-01

    We present a phytosociological overview of the arid and semi-arid montane vegetation of the province of Arequipa in southern Peru. The xerophytic vegetation was studied after extreme rainfall had promoted exceptionally lush vegetation and a high aboveground floristic diversity. We used TWINSPAN for

  3. Mytilus antiquorum J. Sowerby, 1821, and other Pliocene mussels (Mollusca, Bivalvia) from the southern North Sea Basin

    OpenAIRE

    Vervoenen, M.; Wesselingh, F.P.; van Nieulande, F.A.D.

    2000-01-01

    Mytilus antiquorum J. Sowerby, 1821, is recorded from the Coralline Crag Formation of East Anglia (UK) and the Lillo Formation ( Oorderen, Kruisschans and Merksem members) of the Antwerp area (Belgium). The species is diagnosed on the basis of newly collected material and differentiated from modem European mussel species. The presence of M. antiquorum in the southern North Sea Basin is restricted to the Middle (Piacenzian) and early Late Pliocene (Gelasian). A possible occurrence of the spec...

  4. Inconsistent magnetic polarities in magnetite-and greigite-bearing sediments: Understanding complex magnetizations in the late Messinian in the Adana Basin (southern Turkey)

    OpenAIRE

    Lucifora, S.; Dipartimento di Scienze Geologiche, Università Roma Tre, Largo San Leonardo Murialdo 1, IT-00146 Rome, Italy; Cifelli, F.; Dipartimento di Scienze Geologiche, Università Roma Tre, Largo San Leonardo Murialdo 1, IT-00146 Rome, Italy; Mattei, M.; Dipartimento di Scienze Geologiche, Universita` di Roma TRE, Rome; Sagnotti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cosentino, D.; Dipartimento di Scienze Geologiche, Universita` 'Roma Tre', Rome, Italy; Roberts, A. P.; Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia

    2012-01-01

    We present paleomagnetic, rock magnetic and scanning electron microscope data from three upper Messinian stratigraphic sections from the Adana Basin (southern Turkey). The collected samples are from fine-grained units, which were deposited during the Messinian Salinity Crisis (within subchron C3r). Paleomagnetic results reveal an inconsistent polarity record, related to a mixture of magnetite and greigite that hinders determination of a reliable magnetostratigraphy. Three classes of samples a...

  5. The Hydromedusae and its distribution in Chukchi Sea and adjacent southern edge waters of Canada Basin, Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    张金标; 林茂

    2001-01-01

    The present paper is based on materials collected in Chukchi Sea and adjacent southern edge waters of Canada Basin, Arctic Ocean during the period from July to August 1999 on the icebreaker, the R/V “Xuelong”, by the Chinese First Arctic Scientific Expedition. Totally, 8 species of pelagic Hydromedusae were identified, of which 4 species belonged to Anthomedusae, 2 species to Leptomedusae, 1 species to Trachymedusae and 1 species to Narcomedusae, the Neoturris breviconis is recorded for the first time in Chukchi Sea. Their principal morphological characteristics are described and illustrated. The 8 species of Hydromedusae occurring in the Chukchi Sea were all cold water species, of which 6 species belong to neritic species and 2 species to ocean species. According to the geographic distribution of species, they may be divided into three groups: Arctic species, Arctic-boreal species and Boreal-temperate species. From the view-point of zoogeography, species from these waters belong to the Arctic fauna.The abundance of Hydromedusae in Chukchi Sea was generally low, with a mean value of 108 ind.*10-2*m-3. Rathkea octopunctata and Aglantha digitale were dominant species. From the view-point of vertical distribution Aglantha digitale is inhabiting in the depth of 0 300 m and with the maximum in the depth of 50 m to 100 m.

  6. Geochemical evolution of groundwater in southern Bengal Basin: The example of Rajarhat and adjoining areas, West Bengal, India

    Indian Academy of Sciences (India)

    Paulami Sahu; P K Sikdar; Surajit Chakraborty

    2016-02-01

    Detailed geochemical analysis of groundwater beneath 1223 km2 area in southern Bengal Basin along with statistical analysis on the chemical data was attempted, to develop a better understanding of the geochemical processes that control the groundwater evolution in the deltaic aquifer of the region. Groundwater is categorized into three types: `excellent', `good' and `poor' and seven hydrochemical facies are assigned to three broad types: `fresh', `mixed' and `brackish' waters. The `fresh' water type dominated with sodium indicates active flushing of the aquifer, whereas chloride-rich `brackish' groundwater represents freshening of modified connate water. The `mixed' type groundwater has possibly evolved due to hydraulic mixing of `fresh' and `brackish' waters. Enrichment of major ions in groundwater is due to weathering of feldspathic and ferro-magnesian minerals by percolating water. The groundwater of Rajarhat New Town (RNT) and adjacent areas in the north and southeast is contaminated with arsenic. Current-pumping may induce more arsenic to flow into the aquifers of RNT and Kolkata cities. Future large-scale pumping of groundwater beneath RNT can modify the hydrological system, which may transport arsenic and low quality water from adjacent aquifers to presently unpolluted aquifer.

  7. Southern North Sea Basin in Europe: Biodiversity of the Marine Fürstenau Formation Including Early White and Megatooth Sharks

    Directory of Open Access Journals (Sweden)

    C. G. Diedrich

    2012-01-01

    Full Text Available The Fürstenau Formation (Lutetian, Paleogene, Eocene is based on type sections near Fürstenau in Germany (central Europe and is built of 22 meter thick marine glauconitic and strongly bioturbated sands, clays, and a vertebrate-rich conglomerate bed. The conglomerate layer from the Early Lutetian transgression reworked Lower Cretaceous, and Paleogene marine sediments. It is dominated by pebbles from the locally mountains which must have been transported by an ancient river in a delta fan. Marine reworked Lower Cretaceous and Paleogen pebbles/fossils, were derived from the underlying deposits of northern Germany (= southern pre North Sea basin. The benthic macrofauna is cold upwelling water influenced and non-tropical, and medium divers. The vertebrate fish fauna is extremely rich in shark teeth, with about 5,000 teeth per cubic meter of gravel. The most dominant forms are teeth from sand shark ancestors Striatolamia macrota, followed by white shark ancestors Carcharodon auriculatus. Even teeth from the magatooth shark ancestor Carcharocles sokolovi are present in a moderately diverse and condensed Paleogene fish fauna that also includes rays, chimaeras, and more then 80 different bony fish. Fragmentary turtle remains are present, and few terrestrial vertebrates and even marine mammals with phocids, sirenians and possibly whales.

  8. Modelling the impact of a subsurface barrier on groundwater flow in the lower Palar River basin, southern India

    Science.gov (United States)

    Senthilkumar, M.; Elango, L.

    2011-06-01

    Groundwater modelling is widely used as a management tool to understand the behaviour of aquifer systems under different hydrological stresses, whether induced naturally or by humans. The objective of this study was to assess the effect of a subsurface barrier on groundwater flow in the Palar River basin, Tamil Nadu, southern India. Groundwater is supplied to a nearby nuclear power plant and groundwater also supplies irrigation, industrial and domestic needs. In order to meet the increasing demand for groundwater for the nuclear power station, a subsurface barrier/dam was proposed across Palar River to increase the groundwater heads and to minimise the subsurface discharge of groundwater into the sea. The groundwater model used in this study predicted that groundwater levels would increase by about 0.1-0.3 m extending out a distance of about 1.5-2 km from the upstream side of the barrier, while on the downstream side, the groundwater head would lower by about 0.1-0.2 m. The model also predicted that with the subsurface barrier in place the additional groundwater requirement of approximately 13,600 m3/day (3 million gallons (UK)/day) can be met with minimum decline in regional groundwater head.

  9. Structural features and petroleum geology of the fold-thrust belt in the southern Tarim basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xinyuan; LUO Jinhai; WANG Qinghua

    2004-01-01

    The west Kunlun fold-thrust belt (WKFTB) and the Altun fold-thrust belt (AFTB) are respectively located in the southern margin of the Tarim basin, NW China. The analyses of typical structures and regional dynamics of the fold-thrust belts reveal their different structural and petroleum features and mechanisms. WKFTB differs from AFTB by abundant fault-related folds and triangles zones, and was formed by northward extrusion of the west Kunlun orogen. AFTB was affected synchronously by northward extrusion of the Altun orogen and the sinistral strike-slipping of the Altun Fault, so it is characterized by the minor scale and the monotonous structural styles. The Aqike anticline and the Aqike fault, of which the strikes are orthogonal to the strike of the fold-thrust belts, are regarded as the adjustive structures between both of the fold-thrust belts. The oil-gas pools of WKFTB develop mainly in the faulted-related anticline traps, but the oil-gas pools of AFTB develop mainly in the low fault-block and anticlines traps related with the paleo-uplifts. There are different exploration countermeasures for both of the fold-thrust belts.

  10. Hunter-gatherer adaptations and environmental change in the southern Great Basin: The evidence from Pahute and Rainier mesas

    Energy Technology Data Exchange (ETDEWEB)

    Pippin, L.C.

    1998-06-01

    This paper reviews the evidence for fluctuations in past environments in the southern Great Basin and examines how these changes may have affected the strategies followed by past hunter and gatherers in their utilization of the resources available on a highland in this region. The evidence used to reconstruct past environments for the region include botanical remains from packrat middens, pollen spectra from lake and spring deposits, faunal remains recovered from archaeological and geologic contexts, tree-ring indices from trees located in sensitive (tree-line) environments, and eolian, alluvial and fluvial sediments deposited in a variety of contexts. Interpretations of past hunter and gatherer adaptive strategies are based on a sample of 1,311 archaeological sites recorded during preconstruction surveys on Pahute and Rainier mesas in advance of the US Department of Energy`s nuclear weapons testing program. Projectile point chronologies and available tree-ring, radiocarbon, thermoluminescence and obsidian hydration dates were used to assign these archaeological sites to specific periods of use.

  11. Seismicity in the Raton Basin of Southern Colorado and Northern New Mexico, USA, as Recorded by a Local Array

    Science.gov (United States)

    Macartney, H.

    2013-12-01

    Microseismic events (Basin of southern Colorado and northern New Mexico, USA, over a period of 18 months following the occurrence of a 5.3 magnitude event near Trinidad CO in August, 2011. Micro-seismicity was observed in the region, concentrated in six clusters at depths of 6-12 km below the surface, deep in the basement, and 4-10 km below zones used for fluid disposal from an overlying coalbed methane natural gas field. Clusters are separated from disposal zones by large aseismic intervals. The clusters are mixed in character; both planar and elongate amorphous swarms, some continually active and some as short-lived bursts, with larger initial events tending to occur deeper and smaller after-shocks propagating upward and away from the nucleating events. Magnitudes range between 0 and 3, with the vast majority being less than 1.5M. Most of the clusters have no disposal wells above and no seismic activity was correlated with changes in fluid disposal. No seismicity was detected from hydraulic fracturing operations.

  12. Drought and vegetation analysis in Tarsus River Basin (Southern Turkey using GIS and Remote Sensing data

    Directory of Open Access Journals (Sweden)

    Celalettin Duran

    2015-12-01

    Full Text Available In this study, the effects of topographic variables on drought and vegetation in dry season have been examined. Distributions of dry conditions in Tarsus River Basin were derived using the NDVI, NDMI indexes and LST (Land Surface Temperature from landsat8 image bands. There is large difference in elevation in the study area. Local climatic conditions are formed under the influence of altitude and morphological structure. Narrow and deep valleys in the topography create more moderate temperature/moisture conditions and are the main distribution area of tall forest vegetation. High radiation in the highest plateau system and, extreme temperature/moisture values led short-lived herbaceous vegetation to spread. Due to high insolation/temperature and restricted marine affect, establishment of scrub vegetation can be observed both in mid-elevation and south-sloping plateau of the study area. Anthropogenic agricultural fields form the land surface with the potential of high temperature/evapotranspiration rate in harvesting periods. Broadleaf plant species spread in areas close to the base of the valley stream. Plantation forest has been created in areas of near-shore sand dunes and very small delta (marsh. Variability in topography also increases the width of the combination of factors that shape the vegetation. This also enables the number of taxa to increase and unusual taxa to co-exist.

  13. Fault zone characteristics and basin complexity in the southern Salton Trough, California

    Science.gov (United States)

    Persaud, Patricia; Ma, Yiran; Stock, Joann M.; Hole, John A.; Fuis, Gary S.; Han, Liang

    2016-01-01

    Ongoing oblique slip at the Pacific–North America plate boundary in the Salton Trough produced the Imperial Valley (California, USA), a seismically active area with deformation distributed across a complex network of exposed and buried faults. To better understand the shallow crustal structure in this region and the connectivity of faults and seismicity lineaments, we used data primarily from the Salton Seismic Imaging Project to construct a three-dimensional P-wave velocity model down to 8 km depth and a velocity profile to 15 km depth, both at 1 km grid spacing. A VP = 5.65–5.85 km/s layer of possibly metamorphosed sediments within, and crystalline basement outside, the valley is locally as thick as 5 km, but is thickest and deepest in fault zones and near seismicity lineaments, suggesting a causative relationship between the low velocities and faulting. Both seismicity lineaments and surface faults control the structural architecture of the western part of the larger wedge-shaped basin, where two deep subbasins are located. We estimate basement depths, and show that high velocities at shallow depths and possible basement highs characterize the geothermal areas.

  14. Endocrine disruptors in water filters used in the Rio dos Sinos Basin region, Southern Brazil.

    Science.gov (United States)

    Furtado, C M; von Mühlen, C

    2015-05-01

    The activated carbon filter is used in residences as another step in the treatment of drinking water, based on a physical-chemical process to absorb pollutants that are not removed in conventional treatment. Endocrine disruptors (EDCs) are exogenous substances or mixtures of substances that acts on the endocrine system similarly to the endogenously produced hormones, triggering malfunctions and harmful changes to human and animal health. The objective of the present work was to study EDCs through semi-quantitative analysis of residential water filters collected in the region of Rio dos Sinos basin, focusing on two specific classes: hormones and phenols. The solid phase extraction principle was used for the extraction of compounds and gas chromatography coupled with mass spectrometry for the separation and characterization of EDCs. Four samples of residential filters collected from public water distribution and artesian wells, from the cities of Novo Hamburgo and São Leopoldo were analysed. Using the developed methodology, it was possible to detect and comparatively quantify selected EDCs in all studied samples, which indicates the presence of these contaminants in drinking water from different sources.

  15. Molecular and isotopic composition of hydrate-bound and dissolved gases in the southern basin of Lake Baikal, based on an improved headspace gas method

    Science.gov (United States)

    Sakagami, Hirotoshi; Takahashi, Nobuo; Hachikubo, Akihiro; Minami, Hirotsugu; Yamashita, Satoshi; Shoji, Hitoshi; Khlystov, Oleg; Kalmychkov, Gennadiy; Grachev, Mikhail; De Batist, Marc

    2012-12-01

    Assessments of the molecular and isotopic composition of hydrate-bound and dissolved gases in pore water were conducted during the multi-phase gas hydrate project (MHP-09) cruise VER09-03 to the southern basin of Lake Baikal in September 2009. To avoid changes in gas composition during core sampling and transport, various headspace methods were investigated aimed at preserving the dissolved gases in pore water. When distilled water was added to the sediment samples, the concentrations of carbon dioxide and oxygen decreased because of dissolution into the water and/or microbial consumption. When the headspace was not flushed with inert gases, trace levels of hydrogen and ethylene were detected. The findings suggest that best preparation is achieved by flushing the headspace with helium, and adding a saturated aqueous solution of sodium chloride. This improved headspace method served to examine the molecular and isotopic compositions of gas samples retrieved at several new sites in the southern basin. Methane was the major component, and the proportion of ethane ranged widely from 0.0009 to 1.67 mol% of the total hydrocarbon gases. The proportions of propane and higher hydrocarbons were small or less than their detection limits. The carbon isotope signatures suggest that microbial-sourced methane and ethane were dominant in the Peschanka study area, whereas ethane was of thermogenic origin at all other study sites in the southern basin of Lake Baikal.

  16. Prevalence of malformed frogs in Kaoping and Tungkang river basins of southern Taiwan.

    Science.gov (United States)

    Huang, Da-Ji; Chiu, Yuh-Wen; Chen, Chien-Min; Huang, Kai-Hsiang; Wang, Shu-Yin

    2010-05-01

    In this study we found many amphibians with bizarre appearances, known as malformations in Pingtung County southern Taiwan. For this investigation we collected frogs inhabiting the Kaoping and Tungkang river watersheds between February 2006 and June 2007. Among the total number of 10,909 normal frogs (i.e., anurans) collected during the investigation period, the Indian rice frogs (Rana limnocharis) account for the greatest number next is the Chinese bullfrog (Rana rugulosa). Of all the 244 captured malformed frogs, the Indian rice frog account for the greatest proportion. These malformed frogs have their main distribution in upstream areas of these two rivers. Our result indicates that the appearance rate of malformed frogs is 1.8% in the upstream reaches of the Kaoping River and 2.6%, and 0.8%, respectively in the upstream and midstream reaches of the Tungkang river. The most-commonly-found malformation is the lack of palms, followed by the lack of appendages, exostosis, and a malformed appendicular. It is, therefore, reasonable to speculate that the causes for the malformation may be related to the increased organic pollutants and agricultural chemicals used in the upstream reaches of these two rivers. PMID:21047008

  17. Late Givetian ammonoids from Hassi Nebech (Tafilalt Basin, Anti-Atlas, southern Morocco

    Directory of Open Access Journals (Sweden)

    J. Bockwinkel

    2013-02-01

    Full Text Available The Hassi Nebech area of the SE Tafilalt (Tafilalt Basin, Anti-Atlas, Morocco yielded the richest and most diverse late Givetian ammonoid fauna on a global scale. Above the distinctive regional "Lower Marker Bed" (Synpharciceras clavilobum Zone, abundant loosely collected limonitic specimens derive from hypoxic shales of the Taouzites taouzensis to Petteroceras errans zones. The ontogenetic morphometry and intraspecific variability of a total of 30 species representing five families, the Acanthoclymeniidae, Taouzitidae, Pharciceratidae, Petteroceratidae, and Tornoceratidae, are documented. New taxa are: Pseudoprobeloceras praecox n. sp., Scaturites minutus n. gen. n. sp., Darkaoceras velox n. sp., Pharciceras decoratum n. sp., Ph. fornix n. sp., Ph. subconstans n. sp., Ph. involutum n. sp., Lunupharciceras incisum n. sp., Transpharciceras procedens n. gen. n. sp., Stenopharciceras progressum n. sp., Pluripharciceras n. gen. (type species: Synpharciceras plurilobatum Petter, 1959, Plu. orbis n. sp., Synpharciceras frequens n. sp., Lobotornoceras bensaidi n. sp., Nebechoceras eccentricum n. gen. n. sp., and Phoenixites lenticulus n. sp. The documentation of conch and particularly suture ontogeny and intraspecific variability necessitates a revised diagnosis for ten taxa. Manticoceras pontiformis Termier & Termier, 1950, Probeloceras costulatum Petter, 1959, and Pseudoprobeloceras nebechense Bensaïd, 1974 are regarded as subjective junior synonyms of Ps. pernai (Wedekind, 1918. Sandbergeroceras acutum Termier & Termier, 1950 is a subjective synonym of Taouzites taouzensis (Termier & Termier, 1950. Pharciceras applanatum Bensaïd, 1974 is transferred to Extropharciceras. Other forms (Ph. aff. tridens, Ph. cf. subconstans n. sp., Extropharciceras n. sp. 2, Ex. cf. arenicum, Ex. cf. applanatum, Synpharciceras sp., Plu. cf. plurilobatum are described in open nomenclature. doi:10.1002/mmng.201300001

  18. Simulation-optimization aids in resolving water conflict: Temecula Basin, Southern California

    Science.gov (United States)

    Hanson, Randall T.; Faunt, Claudia C.; Schmid, Wolfgang; Lear, Jonathan

    2014-01-01

    The productive agricultural areas of Pajaro Valley, California have exclusively relied on ground water from coastal aquifers in central Monterey Bay. As part of the Basin Management Plan (BMP), the Pajaro Valley Water Management Agency (PVWMA) is developing additional local supplies to replace coastal pumpage, which is causing seawater intrusion. The BMP includes an aquifer storage and recovery (ASR) system, which captures and stores local winter runoff, and supplies it to growers later in the growing season in lieu of ground-water pumpage. A Coastal Distribution System (CDS) distributes water from the ASR and other supplemental sources. A detailed model of the Pajaro Valley is being used to simulate the coupled supply and demand components of irrigated agriculture from 1963 to 2006. Recent upgrades to the Farm Process in MODFLOW (MF2K-FMP) allow simulating the effects of ASR deliveries and reduced pumping for farms in subregions connected to the CDS. The BMP includes a hierarchy of monthly supply alternatives, including a recovery well field around the ASR system, a supplemental wellfield, and onsite farm supply wells. The hierarchy of delivery requirements is used by MF2K-FMP to estimate the effects of these deliveries on coastal ground-water pumpage and recovery of water levels. This integrated approach can be used to assess the effectiveness of the BMP under variable climatic conditions, and to test the impacts of more complete subscription by coastal farmers to the CDS deliveries. The model will help managers assess the effects of new BMP components to further reduce pumpage and seawater intrusion.

  19. Teaching the History of Colonial Peru.

    Science.gov (United States)

    Campbell, Leon G.

    1981-01-01

    Presents a bibliographic review essay on the topic of colonial Peru organized according to the following topics: Pre-Columbian Peru, 5500 B.C.- 1532; the conquest of Peru, 1532-1572; Peru under the Hapsburgs, 1516-1700; Bourbon Peru, 1700-1808; and the coming of independence, 1808-1821. The essay is based on a bibliography composed largely of…

  20. Geology and potential hydrocarbon play system of Lower Karoo Group in the Maamba Coalfield Basin, southern Zambia

    Science.gov (United States)

    Phiri, Cryton; Wang, Pujun; Nyambe, Imasiku Anayawa

    2016-06-01

    This study attempts to augment geology and potential hydrocarbon play system database not only in the Maamba Coalfield basin of southern Zambia but in other similar continental non-marine Karoo rift basins in the region as well. Geological analyses were conducted through extensive outcrops and exposures and subsurface boreholes. Six (6) major lithofacies (diamictites, conglomerates, sandstones, siltstones, coal and mudstones) represents Lower Karoo Group sequence. Four (4) mudstone core samples were prepared for thin section petrography. In addition, six (6) samples of sandstones obtained from outcrops, exposures and cores were impregnated with blue epoxy before thin sectioning in order to facilitate easy recognition of porosity. Quantification of framework grain composition and porosity was achieved by point counting a total of 300 points per thin section. The identification of diagenetic constituents and pore types was made possible by the use of scanning electron microscopy (SEM). Rock-Eval pyrolysis analyses utilised 35 core samples of mudstones and coal. According to results of the analyses, three (3) deposition settings which include; alluvial, fluvial-lacustrine and lacustrine setting are envisaged. . Fluvial-lacustrine deposits are host to mudstones and coal source rocks and sandstone reservoir rocks. Mudstones and coal source rocks gave the total organic carbon (TOC) that is well above the recommended thresholds of 0.5 wt % and 2.5 wt % of gas and oil generation respectively. The hydrogen index (HI) values are mostly below 200 mg HC/g TOC, indicating fair quantities of type III kerogen. The thermal maturity readings measured by temperature Tmax range from 440 to 485 °C in agreement with calculated vitrinite reflectance (Rocalc) range of 0.76-1.57% indicating mature to post mature stages. This maturation is attributed to the burial temperatures and near-surface heat flows by faults. Production Index (PI) values are less than 0.1 suggesting some hydrocarbon

  1. Cenozoic magnetostratigraphy and magnetic properties of the southern Issyk-Kul basin, Kyrgyzstan

    Science.gov (United States)

    Wack, Michael R.; Gilder, Stuart A.; Macaulay, Euan A.; Sobel, Edward R.; Charreau, Julien; Mikolaichuk, Alexander

    2014-08-01

    We present paleomagnetic data from the northern flank of the Tianshan range, southeast of Lake Issyk-Kul (Kyrgyzstan). 613 cores were collected in two parallel sections with a total thickness of 960 m (Chon Kyzylsuu, CK) and 990 m (Jeti Oguz, JO), as well as 48 cores at six sites in a nearby anticline. Rock magnetic analyses identify both magnetite and hematite in the fluvial-lacustrine sediments. The concentration of both minerals, the magnetite:hematite ratio, and the average magnetite grain size increase upward in both sections. Anisotropy of anhysteretic remanent magnetization defines a tectonic fabric with sub-horizontal maximum axes that parallel the strike direction together with intermediate and minimum axes that streak out about a great circle orthogonal to the maximum axes suggestive of a tectonic fabric emplaced during folding. Stepwise thermal demagnetization isolates interpretable magnetization components in 284 samples that define 26 polarity chrons in CK and 19 in JO. A positive fold test, dual polarities and systematic changes in rock-magnetic parameters with depth suggest that the high temperature magnetization component was acquired coevally with deposition. An age model based on a visual magnetostratigraphic correlation of both sections with the geomagnetic polarity time scale defines absolute ages from 26.0 to 13.3 Ma, with a fairly constant sedimentation rate of 9-10 cm/ka. A correlation based on a numerical algorithm arrives at a slightly different conclusion, with deposition ages from 25.2 to 11.0 Ma and sedimentation rates from 5 to 8 cm/ka. In comparison with sedimentation rates found at other magnetostratigraphic sections in the Tianshan realm, we infer that the sedimentary record in this part of the Issyk-Kul Basin precedes the more rapid phase of uplift of the Kyrgyz Tianshan. The onset of deposition and concomitant erosion of the adjacent Terskey Range is in good agreement with independent assessments of the exhumation history of this

  2. Peru : Accounting and Auditing

    OpenAIRE

    World Bank

    2004-01-01

    The report provides an assessment of accounting, financial reporting, and auditing practices within the corporate sector in Peru, using International Financial Reporting Standards (IFRS), and International Standards on Auditing (ISA) as benchmarks, drawing on international experience and best practices in that field. This Report on the Observance of Standards and Codes (ROSC) Accounting & ...

  3. Religious Regimes in Peru

    NARCIS (Netherlands)

    Spier, Fred

    1994-01-01

    This inquiry deals with religion and politics in Peru from the beginning of agrarisation, c. 8000 B.C. up until AD 1991. Of central importance for the analysis are state formation and development, the relations between church and state, the internal and external relations within and among the variou

  4. Constraints from GPS on Block Kinematics of the Transition between the Southern Walker Lane and the Basin and Range Province

    Science.gov (United States)

    Jha, S.; Hammond, W. C.; Kreemer, C.; Blewitt, G.

    2008-12-01

    The southern Walker Lane (SWL) is a part of the Eastern California Shear Zone that lies north of the Mojave region, bounded by the Garlock Fault to the south, the Sierra Nevada to the west, the Basin and Range to the east and by Mono Lake to the north. The region includes many northwest striking right-lateral strike slip and sub-parallel normal faults (e.g. Death Valley/Furnace Creek, Fish Lake Valley, Owens Valley), which together accommodate ~25% of the Pacific/North American relative motion. For many of these faults, and the system as a whole, there appears to be a discrepancy between geodetically and geologically inferred fault slip rates. Since the installation of the EarthScope Plate Boundary Observatory (PBO), and the Nevada Earthquake Response Network (NEARNET) of the University of Nevada, Reno, many recently obtained high- precision GPS data are now available to place improved constraints on the pattern and rates of crustal deformation of this region. In this study we use a block modeling methodology to estimate block motions and fault slip rates from GPS velocities of PBO, NEARNET and BARGEN continuous sites. Time series were obtained from raw RINEX data that we processed using the GIPSY-OASIS II software from the Jet Propulsion Laboratory together with the Ambizap software for ambiguity resolution. We have additionally included earlier published campaign-style velocities, in those areas where we do not have better coverage from other continuous/semi-continuous networks. Geologic slip rates have been obtained from the published literature. We solve for the motion of blocks using the GPS velocities that have been adjusted based on the viscoelastic modeling to estimate long term motion. To evaluate the consistency between the geologic and geodetic data, we compare long-term fault slip to slip rates inferred from geodetic results obtained over Basin and Range. The preliminary results obtained from the block model indicate significant slip at the easternmost

  5. Investigation of the buried structure of the Volturara Irpina Basin (southern Italy) by microtremor and gravimetric data

    Science.gov (United States)

    Maresca, Rosalba; Berrino, Giovanna

    2016-05-01

    We investigated the structure of the Volturara Irpina Plain, a small intra-mountain basin in southern Italy. Microtremor Horizontal-to-Vertical Spectral Ratio (HVSR) measurements were performed on a 50-point grid across the plain, and contour maps of the peak frequencies and maximum amplitudes of the HVSR curves were constructed. In the deepest part of the plain, the fundamental resonance frequencies were 0.8 Hz to 0.9 Hz. Assuming that the HVSR peak frequencies interpret the fundamental resonance frequencies, and taking into account the shear-wave velocity-depth relationship derived from down-hole data, a first thickness-frequency relationship for the plain was estimated. The sediment thickness corresponds to the depth from the ground surface of the seismic basement. A power-law thickness-frequency relationship was also derived through nonlinear regression fitting of the borehole data that intercepted the bedrock. Finally, the contour map of the depth of the seismic basement was constructed by averaging the thickness estimates from the two different approaches. Gravity measurements were also acquired on a 54-point grid across the plain, most of which coincided with microtremor stations. From these data, the Bouguer gravity anomaly was computed with reference to the 1980 Ellipsoid, and using a density of 2670 kg/m3, we propose a three-dimensional interpretation of the buried structure of the plain that is mainly formed by three overlapped layers. The separately obtained microtremor and gravity results were also compared, using constraints from the drillings. Thus, we interpret the first layer as Plio-Pleistocenic sediments mostly composed of clay, silty clay, and gravel. The underlying basement has maximum depth ~ 500 m below ground level (altitude, ~ 200 m a.s.l.), and corresponds to Mesozoic carbonate rocks. These rocks are nonhomogeneous, with an upper, less compact, layer formed by unstable rocks with clay, or fractured rocks with water circulation. This is

  6. Assessing sedimentation rates at Usumacinta and Grijalva river basin (Southern Mexico) using OSL and suspended sediment load analysis: A study from the Maya Classic Period

    Science.gov (United States)

    Munoz-Salinas, E.; Castillo, M.; Sanderson, D.; Kinnaird, T.; Cruz-Zaragoza, E.

    2013-12-01

    Studying sedimentation rates on floodplains is key to understanding environmental changes occurred through time in river basins. The Usumacinta and Grijalva rivers flow most of their travel through the southern part of Mexico, forming a large river basin, crossing the states of Chiapas and Tabasco. The Usumacinta-Grijalva River Basin is within the 10 major rivers of North America, having a basin area of ~112 550 km2. We use the OSL technique for dating two sediment profiles and for obtaining luminescence signals in several sediment profiles located in the streambanks of the main trunk of the Usumacinta and Grijalva rivers. We also use mean annual values of suspended sediment load spanning ~50 years to calculate the sedimentation rates. Our OSL dating results start from the 4th Century, when the Maya Civilization was at its peak during the Classic Period. Sedimentation rates show a notable increase at the end of the 19th Century. The increase of the sedimentation rates seems to be related to changes in land uses in the Sierra Madre de Chiapas and Altos de Chiapas, based on deforestation and land clearing for developing new agrarian and pastoral activities. We conclude that the major environmental change in the basin of the Usumacinta and Grijalva Rivers since the Maya Classic Period was generated since the last Century as a result of an intense anthropogenic disturbance of mountain rain forest in Chiapas.

  7. Evolution of the late Quaternary San Gregorio Magno tectono-karstic basin (southern Italy) inferred from geomorphological, tephrostratigraphical and palaeoecological analyses: tectonic implications

    Science.gov (United States)

    Aiello, G.; Ascione, A.; Barra, D.; Munno, R.; Petrosino, P.; Russo Ermolli, E.; Villani, F.

    2007-03-01

    The Pantano di San Gregorio Magno is a 4.7 km2 large tectono-karstic basin located in the axial belt of the Southern Apennines, an area affected by intense seismicity. The basin was formed in the Middle Pleistocene and is presently undissected. It is filled by lacustrine sediments (clays, silts and pyroclastic sands) passing laterally into alluvial fan deposits. Geomorphological investigations were integrated with tephrostratigraphical, palynological and palaeoecological analyses of a 61 m thick core (not reaching the bedrock). The multiproxy analysis of the S. Gregorio Magno record shows that, over the last 200k yr, the basin hosted a freshwater lake with an oscillating level. Age constraints provided by the tephrostratigraphic record allowed estimation of the sedimentation rate, which varied strongly through time. Evolution of the basin resulted from the complex combination of tectonic subsidence, karst processes and changing amounts of sedimentary inputs. The latter was influenced by allogenic contributions related both to primary and reworked volcanoclastic inputs and was climate-driven. The overall evidence, which indicates that in the long-term the accumulation rate substantially counterbalanced the accommodation space created by faulting, suggests that the basin evolution was also modulated by changing subsidence rates. Copyright

  8. A Study of the Connection Among Basin-Fill Aquifers, Carbonate-Rock Aquifers, and Surface-Water Resources in Southern Snake Valley, Nevada

    Science.gov (United States)

    ,

    2008-01-01

    The Secretary of the Interior through the Southern Nevada Public Lands Management Act approved funding for research to improve understanding of hydrologic systems that sustain numerous water-dependent ecosystems on Federal lands in Snake Valley, Nevada. Some of the streams and spring-discharge areas in and adjacent to Great Basin National Park have been identified as susceptible to ground-water withdrawals (Elliott and others, 2006) and research has shown a high potential for ground-water flow from southern Spring Valley into southern Snake Valley through carbonate rocks that outcrop along a low topographic divide known as the Limestone Hills (Welch and others, 2007). Comprehensive geologic, hydrologic, and chemical information will be collected and analyzed to assess the hydraulic connection between basin-fill aquifers and surface-water resources, water-dependent ecological features, and the regional carbonate-rock aquifer, the known source of many high-discharge springs. Understanding these connections is important because proposed projects to pump and export ground water from Spring and Snake Valleys in Nevada may result in unintended capture of water currently supplying springs, streams, wetlands, limestone caves, and other biologically sensitive areas (fig. 1). The methods that will be used in this study may be transferable to other areas in the Great Basin. The National Park Service, Bureau of Land Management, U.S. Fish and Wildlife Service, and U.S. Forest Service submitted the proposal for funding this research to facilitate science-based land management. Scientists from the U.S. Geological Survey (USGS) Water Resources and Geologic Disciplines, and the University of Nevada, Reno, will accomplish four research elements through comprehensive data collection and analysis that are concentrated in two distinct areas on the eastern and southern flanks of the Snake Range (fig. 2). The projected time line for this research is from July 2008 through September 2011.

  9. Contribution of the airborne geophysical survey to the study of the regolith : A case study in southern Paris Basin.

    Science.gov (United States)

    Prognon, Francois; Lacquement, Fréderic; Deparis, Jacques; Martelet, Guillaume; Perrin, José

    2010-05-01

    Studies of soil and subsoil, also called regolith, are at the crossroads of scientific new challenging questions as well as new environmental needs. Historically, geological maps were focussed on solid geology. Present societal needs increasingly require knowledge of regolith properties: superficial studies combining geology, geochemistry and geophysics become essential to better understand the natural processes which govern the repartition and evolution of subsoil formations. Such progress is critical to better orient the use and management of natural and groundwater resources. Among other techniques, airborne geophysics is appropriate to provide information on near surface, because of i) its high spatial coverage ii) the rapidity of acquisition and iii) the variety of available sensors (magnetic, spectral radiometry, electromagnetic …). We illustrate the results of an airborne geophysical survey carried out in France, in "Région Centre" administrative region in the southern part of the Paris Basin. Spectral radiometry data were collected throughout "Région Centre" with a line spacing of 1 km. This method provides maps of potassium (K), uranium (U) and thorium (Th) which are the only naturally occurring elements with direct or indirect radioisotopes that produce gamma rays of sufficient intensity to be measured at airborne survey heights. Gamma-rays emitted from the Earth surface are related to the primary mineralogy and geochemistry of the bedrock and/or the nature of secondary weathering including regolith materials. Obtained images are confronted with former geological investigations (1:50 000e geological maps). Geophysical data and geological maps are generally consistent on most of the covered area since the first-rate information delivered by the spectrometry derives from the geochemistry of the solid geology. Second-rate gamma-ray responses come from superimposed allochtonous deposits as well as in situ geochemical modifications. For instance

  10. Diagenesis and reservoir quality of the Lower Cretaceous Quantou Formation tight sandstones in the southern Songliao Basin, China

    Science.gov (United States)

    Xi, Kelai; Cao, Yingchang; Jahren, Jens; Zhu, Rukai; Bjørlykke, Knut; Haile, Beyene Girma; Zheng, Lijing; Hellevang, Helge

    2015-12-01

    The Lower Cretaceous Quantou Formation in the southern Songliao Basin is the typical tight oil sandstone in China. For effective exploration, appraisal and production from such a tight oil sandstone, the diagenesis and reservoir quality must be thoroughly studied first. The tight oil sandstone has been examined by a variety of methods, including core and thin section observation, XRD, SEM, CL, fluorescence, electron probing analysis, fluid inclusion and isotope testing and quantitative determination of reservoir properties. The sandstones are mostly lithic arkoses and feldspathic litharenites with fine to medium grain size and moderate to good sorting. The sandstones are dominated by feldspar, quartz, and volcanic rock fragments showing various stages of disintegration. The reservoir properties are quite poor, with low porosity (average 8.54%) and permeability (average 0.493 mD), small pore-throat radius (average 0.206 μm) and high displacement pressure (mostly higher than 1 MPa). The tight sandstone reservoirs have undergone significant diagenetic alterations such as compaction, feldspar dissolution, quartz cementation, carbonate cementation (mainly ferrocalcite and ankerite) and clay mineral alteration. As to the onset time, the oil emplacement was prior to the carbonate cementation but posterior to the quartz cementation and feldspar dissolution. The smectite to illite reaction and pressure solution at stylolites provide a most important silica sources for quartz cementation. Carbonate cements increase towards interbedded mudstones. Mechanical compaction has played a more important role than cementation in destroying the reservoir quality of the K1q4 sandstone reservoirs. Mixed-layer illite/smectite and illite reduced the porosity and permeability significantly, while chlorite preserved the porosity and permeability since it tends to be oil wet so that later carbonate cementation can be inhibited to some extent. It is likely that the oil emplacement occurred

  11. Variability in the microbial communities and hydrothermal fluid chemistry at the newly discovered Mariner hydrothermal field, southern Lau Basin

    Science.gov (United States)

    Takai, Ken; Nunoura, Takuro; Ishibashi, Jun-Ichiro; Lupton, John; Suzuki, Ryohei; Hamasaki, Hiroshi; Ueno, Yuichiro; Kawagucci, Shinsuke; Gamo, Toshitaka; Suzuki, Yohey; Hirayama, Hisako; Horikoshi, Koki

    2008-06-01

    A newly discovered hydrothermal field called the Mariner field on the Valu Fa Ridge in the southern Lau Basin was explored and characterized with geochemical and microbiological analyses. The hydrothermal fluid discharging from the most vigorous vent (Snow Chimney, maximum discharge temperature 365°C) was boiling at the seafloor at a depth of 1908 m, and two distinct end-member hydrothermal fluids were identified. The fluid chemistry of the typical Cl-enriched and Cl-depleted hydrothermal fluids was analyzed, as was the mineralogy of the host chimney structures. The variability in the fluid chemistry was potentially controlled by the subseafloor phase-separation (vapor loss process) and the microbial community activities. Microbial community structures in three chimney structures were investigated using culture-dependent and -independent techniques. The small subunit (SSU) rRNA gene clone analysis revealed that both bacterial and archaeal rRNA gene communities on the chimney surfaces differed among three chimneys. Cultivation analysis demonstrated significant variation in the culturability of various microbial components among the chimneys, particularly of thermophilic H2-oxidizing (and S-oxidizing) chemolithoautotrophs such as the genera Aquifex and Persephonella. The physical and chemical environments of chimney surface habitats are still unresolved and do not directly extrapolate the environments of possible subseafloor habitats. However, the variability in microbial community found in the chimneys also provides an insight into the different biogeochemical interactions potentially affected by the phase separation of the hydrothermal fluids in the subseafloor hydrothermal habitats. In addition, comparison with other deep-sea hydrothermal systems revealed that the Mariner field microbial communities have unusual characteristics.

  12. Differences in nitrous oxide distribution patterns between the Bering Sea basin and Indian Sector of the Southern Ocean

    Institute of Scientific and Technical Information of China (English)

    CHEN Liqi; ZHANG Jiexia; ZHAN Liyang; LI Yuhong; SUN Heng

    2014-01-01

    Nitrous oxide (N2O) distribution patterns in the Bering Sea basin (BSB) and Indian Sector of the Southern Ocean (ISSO) were described and compared. In both sites, the waters were divided into four layers:surface layer, subsurface layer, N2O maximum layer, and deep water. Simulations were made to find out the most important factors that regulate the N2O distribution patterns in different layers of both sites. The results showed that in the surface water, N2O was more understaturated in the ISSO than the BSB. This phenom-enon in the surface water of ISSO may result from ice melt water intrusion and northeastward transport of the Antarctic surface water. Results of the rough estimation of air-sea fluxes during the expedition were (-0.34±0.07)-(-0.64±0.13) μmol/(m2·d) and (-1.47±0.42)-(-1.77±0.51) μmol/(m2·d) for the BSB and the ISSO, respectively. Strongly stratified surface layer and temperature minimum layer restricted exchange across the thermocline. The N2O maximum existed in higher concentration and deeper in the BSB than the ISSO, but their contribution to the upper layer by eddy diffusions was negligible. In deep waters, a concen-tration difference of 5 nmol/L N2O between these two sites was found, which suggested that N2O produc-tion occurred during thermohaline circulation. N2O may be a useful tracer to study important large-scale hydrographic processes.

  13. A structurally controlled fan-delta complex at the southern margin of the peninsular range forearc basin complex (Baja California)

    Energy Technology Data Exchange (ETDEWEB)

    Morris, W.R.; Busby-Spera, C. (Univ. of California, Santa Barbara (USA))

    1990-05-01

    A confined trunk fan delta and its structurally controlled tributary fan deltas are extremely well exposed along the southern margin of the Rosario embayment. This fan-delta complex consists of nonmarine to deep marine deposits almost continuously exposed for over 20 km in the down-paleoslope direction. Facies and stratal patterns in the fan-delta complex were controlled by local faulting, climatic variation, and eustasy, resulting in relative sea level fluctuations. Basin bathymetry and drainage patterns were controlled by a series of half-grabens that formed along north-south-trending faults that lay along the northern margin of an east-west-trending depression. Breccias were initially shed into the north-south-trending half-grabens; axial drainage systems were later established within the grabens, making up the tributary fan deltas. These tributary fan deltas fed a voluminous trunk fan delta confined to the east-west-trending depression. The trunk and tributary fan delta deposits show two major progradational to retrogradational cycles that record relative sea level fluctuations. Progradation in the shallow-marine environment is represented by conglomerate channels cut into ripple-laminated or bioturbated siltstone and HCS sandstones, overlain by conglomerate mouth bar deposits interstratified with nearshore sandstone deposits. Retrogradation in the shallow marine environment is recorded by either a vertical clastic facies transition or a clastic-carbonate facies transition. The clastic facies transition consists of nearshore sandstone deposits overlain by offshore bioturbated siltstones. The clastic-carbonate facies transition consists of the development of red algal patch reefs and rhodoliths on top of fan-delta conglomeratic lobes, mudstone and sandstone bank channel margins, or paleobasement highs. The clastic-carbonate facies transition reflects low sediment supply controlled by climatic conditions.

  14. Paleoclimatic implications of fossil shoreline deposits in the southern basin and range province during the Pleistocene-Holocene transition

    Science.gov (United States)

    Kowler, A. L.

    2010-12-01

    Paleolake shoreline deposits throughout the southern Basin and Range (SBAR) signify past intervals of steady-state climatic conditions occuring during the late Pleistocene slightly before, as well as after the Last Glacial Maximum (LGM; ~23-19 Ka). Unfortunately, a lack of knowledge about the age of fossil shoreline deposits—due to C-14 related uncertainties and incomplete dating of shorelines—has resulted in a large gap in our knowledge about past climatic and surface hydrologic conditions in the SBAR. Several studies collectively reveal multiple lake level oscillations during the LGM and last part of the Pleistocene, with reasonably well dated shoreline deposits existing for only four paleolakes: one in central New Mexico (Estancia), two in southwestern New Mexico (Playas and Cloverdale), and one in southeastern Arizona (Cochise). In summary, there is evidence for a pre-LGM high-stand at Cochise (>26 Ka), LGM high-stands at Estancia and Cloverdale (>20-16 Ka), deglacial age high-stands at Playas and Cochise (16-13 Ka), and latest Pleistocene-early Holocene still stands of as yet undetermined elevation at Playas and Estancia (13-9K). Further, the absence of high-stands from 11-10 Ka suggests that the Younger Dryas climatic reversal—which is detected in the stable O isotopic composition of speleothems from Cave-of-the-Bells in southeastern Arizona—was marked there by a decrease in mean annual air temperature without a significant increase in precipitation. Alternatively, if a return to glacial precipitation levels did occur, then it was for an interval so short that sedimentological evidence was not preserved. This presentation will cover the afore mentioned chronologies, along with discussion about associated atmospheric circulation patterns in the SBAR and across western North America.

  15. When the waves of European Neolithization met: first paleogenetic evidence from early farmers in the southern Paris Basin.

    Directory of Open Access Journals (Sweden)

    Maïté Rivollat

    Full Text Available An intense debate concerning the nature and mode of Neolithic transition in Europe has long received much attention. Recent publications of paleogenetic analyses focusing on ancient European farmers from Central Europe or the Iberian Peninsula have greatly contributed to this debate, providing arguments in favor of major migrations accompanying European Neolithization and highlighting noticeable genetic differentiation between farmers associated with two archaeologically defined migration routes: the Danube valley and the Mediterranean Sea. The aim of the present study was to fill a gap with the first paleogenetic data of Neolithic settlers from a region (France where the two great currents came into both direct and indirect contact with each other. To this end, we analyzed the Gurgy 'Les Noisats' group, an Early/Middle Neolithic necropolis in the southern part of the Paris Basin. Interestingly, the archaeological record from this region highlighted a clear cultural influence from the Danubian cultural sphere but also notes exchanges with the Mediterranean cultural area. To unravel the processes implied in these cultural exchanges, we analyzed 102 individuals and obtained the largest Neolithic mitochondrial gene pool so far (39 HVS-I mitochondrial sequences and haplogroups for 55 individuals from a single archaeological site from the Early/Middle Neolithic period. Pairwise FST values, haplogroup frequencies and shared informative haplotypes were calculated and compared with ancient and modern European and Near Eastern populations. These descriptive analyses provided patterns resulting from different evolutionary scenarios; however, the archaeological data available for the region suggest that the Gurgy group was formed through equivalent genetic contributions of farmer descendants from the Danubian and Mediterranean Neolithization waves. However, these results, that would constitute the most ancient genetic evidence of admixture between farmers

  16. Multiple Suppression and Imaging of Marine Seismic Data from The Shallow Water Area in Southern East China Sea Shelf Basin

    Science.gov (United States)

    Shi, J.; Luan, X.; Yang, C.

    2015-12-01

    Neither surface-related multiple elimination(SRME) nor predictive de-convolution method is effective to suppress the multiple of marine seismic data from the shallow water area. The former method needs the accurate reflection of seafloor, which is mixed with the direct wave in the near offset range. The other one could probably lose the primary wave when applied to the shallow water seismic data. We introduced the new method: deterministic water-layer de-multiple method (DWD) which is capable for the poor extrapolate result of near-offset traces. Firstly, the data shifts as downward continuation in tau-p domain with a water-layer period and the multiple model will be obtained. Then, the original seismic subtracts adaptively with the multiple model. Finally, we would get the de-multiple data after inverse tau-p transform. Marine seismic real data is from southern part of East China Sea Shelf Basin. This area has become the potential target for marine hydrocarbon exploration, it is located in the junction of the Eurasian plate pacific plate and Indian plate. Because the average water depth is less than 100 meters, seismic data contains abundant of multiple, especially the surface-related multiple. As a result it is difficult to distinguish the strata structure clearly. We used DWD approach to remove the water-layer multiple, cut off the seafloor reflection events and then suppressed the residual surface-related multiple by the traditional SRME. At last , the radon transform was applied to eliminate the multiple with long period . With these steps, we suppressed the multiple of marine seismic data from this area effectively. After multiple is removed , we acquired more accurate velocity to build the velocity model of migration. With the pre-stack migration technique, reflections from each geological period are shown clearly in the seismic section. This work was supported by the National Science Foundation of China(grant no. 41476053).

  17. When the waves of European Neolithization met: first paleogenetic evidence from early farmers in the southern Paris Basin.

    Science.gov (United States)

    Rivollat, Maïté; Mendisco, Fanny; Pemonge, Marie-Hélène; Safi, Audrey; Saint-Marc, Didier; Brémond, Antoine; Couture-Veschambre, Christine; Rottier, Stéphane; Deguilloux, Marie-France

    2015-01-01

    An intense debate concerning the nature and mode of Neolithic transition in Europe has long received much attention. Recent publications of paleogenetic analyses focusing on ancient European farmers from Central Europe or the Iberian Peninsula have greatly contributed to this debate, providing arguments in favor of major migrations accompanying European Neolithization and highlighting noticeable genetic differentiation between farmers associated with two archaeologically defined migration routes: the Danube valley and the Mediterranean Sea. The aim of the present study was to fill a gap with the first paleogenetic data of Neolithic settlers from a region (France) where the two great currents came into both direct and indirect contact with each other. To this end, we analyzed the Gurgy 'Les Noisats' group, an Early/Middle Neolithic necropolis in the southern part of the Paris Basin. Interestingly, the archaeological record from this region highlighted a clear cultural influence from the Danubian cultural sphere but also notes exchanges with the Mediterranean cultural area. To unravel the processes implied in these cultural exchanges, we analyzed 102 individuals and obtained the largest Neolithic mitochondrial gene pool so far (39 HVS-I mitochondrial sequences and haplogroups for 55 individuals) from a single archaeological site from the Early/Middle Neolithic period. Pairwise FST values, haplogroup frequencies and shared informative haplotypes were calculated and compared with ancient and modern European and Near Eastern populations. These descriptive analyses provided patterns resulting from different evolutionary scenarios; however, the archaeological data available for the region suggest that the Gurgy group was formed through equivalent genetic contributions of farmer descendants from the Danubian and Mediterranean Neolithization waves. However, these results, that would constitute the most ancient genetic evidence of admixture between farmers from both Central

  18. Late Quaternary tectonics in the inner Northern Apennines (Siena Basin, southern Tuscany, Italy) and their seismotectonic implication

    Science.gov (United States)

    Brogi, Andrea; Capezzuoli, Enrico; Martini, Ivan; Picozzi, Matteo; Sandrelli, Fabio

    2014-05-01

    Defining the most recent Quaternary tectonics represents a challenging task for neotectonic, palaeoseismological and seismotectonic studies. This paper focuses on an integrated approach to reconstructing the latest Quaternary deformation affecting the northern part of the Siena Basin (inner Northern Apennines, i.e., southern Tuscany, Italy) near the town of Siena, and to discuss the seismological implications. Field work and structural and stratigraphic analyses, coupled with the interpretation of reflection seismic lines, have been combined to define the geometry, kinematics and age of mesoscopic to map-scale faults which have affected the mainly Quaternary continental and Pliocene marine deposits. The resulting dataset describes a tectonic setting characterized by coeval SW- and NW-trending transtensional and normal faults, respectively, dissecting alluvial sediments younger than 23.9 ± 0.23 ka. Seismic interpretation sheds light on the geometrical setting of the faults at deeper levels, down to 1-2 km, and provides support for the presence of a wide brittle shear zone defined by conjugated fault segments, locally giving rise to an asymmetrical negative flower-like structure. Faults and their damage zones have controlled (and still control) the discharge of gas vents (mainly CO2 and H2S) and hydrothermal circulation (which deposits travertine) since at least 23.216 ± 0.124 ka. The resulting complete data set provides support for our description of the Neogene-Quaternary tectonics which were active until the late Quaternary, providing additional information about the seismotectonic framework of an area characterized by low seismicity and generally low-magnitude earthquakes (M < 4), but having experienced significant seismic events over the last few centuries.

  19. Fossil Cenozoic crassatelline bivalves from Peru: New species and generic insights

    Directory of Open Access Journals (Sweden)

    Thomas J. DeVries

    2016-08-01

    Full Text Available Discoveries of new fossil Cenozoic crassatellines in Peru provide a new phylogenetic perspective on “large” Neogene genera, in which four lineages are considered to have arisen independently from different Paleogene Crassatella ancestors. Latest Oligocene and early Miocene species of the new genus Tilicrassatella gen. nov.―T. ponderosa, T. torrens sp. nov., and T. sanmartini sp. nov. from the East Pisco Basin―probably evolved from the late Eocene species, Crassatella rafaeli sp. nov., which itself differed in significant respects from slightly older species of the East Pisco Basin, C. neorhynchus and C. pedroi sp. nov. The paciphilic genus, Hybolophus, is raised to full generic status. Added to its ranks are the East Pisco Miocene species H. maleficae sp. nov., H. terrestris sp. nov., and the oldest species of the genus, the late Eocene or Oligocene H. disenum sp. nov. from the Talara Basin of northern Peru. Kalolophus gen. nov., encompassing circum-Caribbean fossil species, the extant species, K. speciosus, and the trans-isthmus species, K. antillarum, appears to have evolved from the early Oligocene Floridian species, Crassatella portelli sp. nov. The genus Marvacrassatella is a western Atlantic Miocene lineage most likely descended from Kalolophus. The genus Eucrassatella is restricted to Australian and New Zealand taxa. The Eocene New Zealand species, Spissatella media, is transferred to Eucrassatella and deemed a candidate for the most recent common ancestor of younger Eucrassatella and all Spissatella species. In the southern Pacific Ocean, the circum-Caribbean region, and tropical western America, crassatelline lineages developed one or more of the following characters: large resilifers, smooth ventral margins, and an extended left anterior cardinal tooth. Some of these late Paleogene convergent character changes might have countered increased shear forces exerted on the crassatelline valves while burrowing into finer-grained and

  20. Three cycles of sedimentation in ancient sedimentary basins of southern Ireland: insights from detrital zircon U-Pb ages

    Science.gov (United States)

    Fairey, Brenton; Kerrison, Aidan; Meere, Patrick; Mulchrone, Kieran; Linnemann, Ulf; Hofmann, Mandy; Gaertner, Andreas; Sonntag, Benita-Lisette; Byrne, Keith

    2016-04-01

    Previous work has shown that sedimentary rocks from the Lower Devonian Dingle Basin were uplifted and recycled by Acadian orogenic activity into the Upper Devonian Munster Basin. This is particularly applicable for sediments deposited in the western part of the Munster Basin. In the present study, a new dataset of U-Pb ages for detrital zircons has been established that spans a large geographic area which includes the Dingle and Munster basins as well as the offshore Mesozoic North Celtic Sea, South Celtic Sea, 'Goban Spur' and Fastnet basins. The study is the first of its kind in any of these sedimentary basins. The aim is to investigate whether sediments deposited in the offshore basins during the Mesozoic reflect three erosion-deposition cycles. Detritus that has undergone three sedimentary cycles would yield super-mature sediments suitable for hydrocarbon storage. Detrital zircon age spectra for Lower Devonian Dingle Basin samples indicate strong sediment input from Avalonian (~600 Ma) and Laurentian (~1.7 Ga and ~1.1 Ga) sources with some input from Caledonian orogenic sources (400-480 Ma). Detrital zircon age spectra in the western Munster Basin largely reflect input from Caledonian-aged igneous crustal input (400-480 Ma) and Laurentian sources. An Avalonian component is not detected in any of the samples from the western Munster Basin. In the central and eastern parts of the Munster Basin, detrital zircon age spectra indicate that the dominant sources of detritus are derived from Laurentia and from Caledonian igneous rocks. In contrast to the western part of the basin, age components around 600 Ma are present in some samples and represent an Avalonian source. These signals are echoed, at varying degrees, in detrital age spectra from Jurassic and Cretaceous samples of the central North Celtic Sea Basin. These age spectra also indicate a significant contribution of detritus from Avalonian terrane. The Avalonian signature is completely absent from Jurassic

  1. Determining Deep Basin Structure of the Hueco and southern Mesilla Bolsons, West Texas, Southern New Mexico and Northern Chihuahua Using Nonseismic Geophysical Techniques

    Science.gov (United States)

    Doser, D. I.; Avila, V.; Budhathoki, P.; Marrufo, S.; Montana, C. J.; Kaip, G.; Moncada, M.; Dena Ornelas, O.

    2012-12-01

    The Hueco and southern Mesilla bolsons are the primary groundwater source for much of the El Paso/Ciudad Juarez metropolitan region of over 1 million residents. The bolsons lie at the point where the strike of the southern Rio Grande rift changes from north-south to northwest-southeast, likely due to its interaction with pre-existing Mesozoic and Paleozoic structures. Tectonic activity continues with recent (Mexico border.

  2. Child nutrition: Peru

    International Nuclear Information System (INIS)

    Malnutrition stunts physical growth and/or limits mental development in one child out of three in developing countries and is a factor in one-third of the 13 million child deaths which occur annually in developing countries. The Department of Technical Co-operation is sponsoring a programme, with technical support from the Human Health Division, to evaluate the effectiveness of a Government food supplement intervention to combat malnutrition in Peru. (IAEA)

  3. Fairy chimneys in Peru

    CERN Document Server

    Sparavigna, Amelia Carolina

    2011-01-01

    Erosion creates beautiful landscapes. A large part of them is known just by the local population. Google Maps can help in locating the places, study them and start any project for preservation. An interesting example is given by a landscape of fairy chimneys in Peru, near San Pedro de Larcay. It is remarkable the fact that some of them have been adapted as dwelling places.

  4. Giant Otters in Peru

    Directory of Open Access Journals (Sweden)

    Schenk C.

    1992-02-01

    Full Text Available We are in the second year of fieldwork surveying for Giant Otters in the southeastern rainforest of Peru, in three areas with differing levels of legal protection. While there is some illegal hunting still happening outside the protected areas, the main threat to the otters is badly-conducted tourism. Well-organised tourism can be a promising argument for establishing protected areas like national parks.

  5. New seismo-stratigraphic data of the Volturno Basin (northern Campania, Tyrrhenian margin, southern Italy: implications for tectono-stratigraphy of the Campania and Latium sedimentary basins

    Directory of Open Access Journals (Sweden)

    Ennio Marsella

    2011-07-01

    Full Text Available A geological section of the Volturno Basin (northern Campania, continental margin, Italy has been constructed based on new multi-channel seismic data, to show the stratigraphic relationships between the filling in the Quaternary basin and the Meso-Cenozoic acoustic basement. The new seismic sections presented here outline the underlying structures of the basin and their relationships to the filling in the Quaternary basin. Deep exploration wells in Campania and Latium on the Tyrrhenian margin have gathered litho-stratigraphic and commercial multi-channel seismic data that can be used for better integration of the geological data for the area under study. The trending of the seismic units is controlled by the Massico Structural High, which forms the boundary of the Volturno Basin towards the north-west. This produces a geometry that is characteristic of a fan complex, with NE-SW trending. This qualitative calibration of the seismic sequences that fill the sedimentary basin was carried out through the litho-stratigraphic data of the «Castelvolturno 2» well, which highlights the pyroclastic layers and conglomeratic strata of the lagoon and delta environments as they evolve upwards towards marine sediments. Seismo-stratigraphic analysis shows the complex depositional geometries of the filling in the Volturno Basin, which overlie the Meso-Cenozoic carbonatic basement and the related flysch deposits. Coupled with regional geological evidence, the data interpretation here suggests that the Volturno Basin represents a half-graben structure that is characterized by down-thrown blocks along normal faults.

  6. Development, transnational religion, and the power of ideas in the High Provinces of Cusco, Peru

    OpenAIRE

    Elizabeth Olson

    2006-01-01

    I examine the enmeshment of transnationally networked religious organizations in predominantly Quechua communities in the southern Andes of Peru. I aim specifically to understand the multiple ways in which transnational religious organizations contribute to the construction of development epistemologies, or the socioeconomics of development truths. Peru has been undergoing a religious transformation similar to the rest of Latin America, with Evangelical and other non-Catholic faiths now well ...

  7. Interbasin flow in the Great Basin with special reference to the southern Funeral Mountains and the source of Furnace Creek springs, Death Valley, California, U.S.

    Science.gov (United States)

    Belcher, W.R.; Bedinger, M.S.; Back, J.T.; Sweetkind, D.S.

    2009-01-01

    Interbasin flow in the Great Basin has been established by scientific studies during the past century. While not occurring uniformly between all basins, its occurrence is common and is a function of the hydraulic gradient between basins and hydraulic conductivity of the intervening rocks. The Furnace Creek springs in Death Valley, California are an example of large volume springs that are widely accepted as being the discharge points of regional interbasin flow. The flow path has been interpreted historically to be through consolidated Paleozoic carbonate rocks in the southern Funeral Mountains. This work reviews the preponderance of evidence supporting the concept of interbasin flow in the Death Valley region and the Great Basin and addresses the conceptual model of pluvial and recent recharge [Nelson, S.T., Anderson, K., Mayo, A.L., 2004. Testing the interbasin flow hypothesis at Death Valley, California. EOS 85, 349; Anderson, K., Nelson, S., Mayo, A., Tingey, D., 2006. Interbasin flow revisited: the contribution of local recharge to high-discharge springs, Death Valley, California. Journal of Hydrology 323, 276-302] as the source of the Furnace Creek springs. We find that there is insufficient modern recharge and insufficient storage potential and permeability within the basin-fill units in the Furnace Creek basin for these to serve as a local aquifer. Further, the lack of high sulfate content in the spring waters argues against significant flow through basin-fill sediments and instead suggests flow through underlying consolidated carbonate rocks. The maximum temperature of the spring discharge appears to require deep circulation through consolidated rocks; the Tertiary basin fill is of insufficient thickness to generate such temperatures as a result of local fluid circulation. Finally, the stable isotope data and chemical mass balance modeling actually support the interbasin flow conceptual model rather than the alternative presented in Nelson et al. [Nelson

  8. The management of abandoned sites at the basin collieries of center and southern France and the procedure of stoppage of mining works

    International Nuclear Information System (INIS)

    The basin collieries of center and southern France (HBCM) have launched since 1993 the procedures of stoppage of mining works as foreseen by the mining rights and which will lead to the renunciation of their 148 concessions once the remediation of the sites has been completed. In order to cope with the enormous work of file and work follow up, a rigorous procedure and organization has been implemented in order to obtain all necessary prefecture by-laws by the end of 2005. (J.S.)

  9. Integrative geomorphological mapping approach for reconstructing meso-scale alluvial fan palaeoenvironments at Alborz southern foothill, Damghan basin, Iran

    Science.gov (United States)

    Büdel, Christian; Majid Padashi, Seyed; Baumhauer, Roland

    2013-04-01

    Alluvial fans and aprons are common depositional features in general Iranian geomorphology. The countries major cities as well as settlements and surrounding area have often been developed and been built up on this Quaternary sediment covers. Hence they periodically face the effects of varying fluvial and slope-fluvial activity occurring as part of this geosystem. The Geological Survey of Iran therefore supports considerable efforts in Quaternary studies yielding to a selection of detailed mapped Quaternary landscapes. The studied geomorphologic structures which are settled up around an endorheic basin in Semnan Province represent a typical type of landform configuration in the area. A 12-km-transect was laid across this basin and range formation. It is oriented in north-south direction from the southern saltpan, called "Kavir-e-Haj Aligholi"/"Chah-e-Jam" ("Damghan Kavir"), across a vast sandy braided river plain, which is entering from the north east direction of the city of Shahroud. At its northern rim it covers alluvial sediment bodies, which are mainly constituted by broad alluvial aprons, fed by watersheds in Alborz Mountains and having their genetic origins in Mio-/Pliocene times. During this study a fully analytical mapping system was used for developing a geodatabase capable of integrating geomorphological analyses. Therefore the system must provide proper differentiation of form, material and process elements as well as geometric separation. Hence the German GMK25 system was set up and slightly modified to fit to the specific project demands. Due to its structure it offers most sophisticated standards and scale independent hierarchies, which fit very well to the software-determinated possibilities of advanced geodatabase applications. One of the main aspects of mapping Quaternary sediments and structures is to acquire a proper description and systematic correlation and categorization of the belonging mapping-objects. Therefore the team from GSI and

  10. Peru Mercury Inventory 2006

    Science.gov (United States)

    Brooks, William E.; Sandoval, Esteban; Yepez, Miguel A.; Howard, Howell

    2007-01-01

    In 2004, a specific need for data on mercury use in South America was indicated by the United Nations Environmental Programme-Chemicals (UNEP-Chemicals) at a workshop on regional mercury pollution that took place in Buenos Aires, Argentina. Mercury has long been mined and used in South America for artisanal gold mining and imported for chlor-alkali production, dental amalgam, and other uses. The U.S. Geological Survey (USGS) provides information on domestic and international mercury production, trade, prices, sources, and recycling in its annual Minerals Yearbook mercury chapter. Therefore, in response to UNEP-Chemicals, the USGS, in collaboration with the Economic Section of the U.S. Embassy, Lima, has herein compiled data on Peru's exports, imports, and byproduct production of mercury. Peru was selected for this inventory because it has a 2000-year history of mercury production and use, and continues today as an important source of mercury for the global market, as a byproduct from its gold mines. Peru is a regional distributor of imported mercury and user of mercury for artisanal gold mining and chlor-alkali production. Peruvian customs data showed that 22 metric tons (t) of byproduct mercury was exported to the United States in 2006. Transshipped mercury was exported to Brazil (1 t), Colombia (1 t), and Guyana (1 t). Mercury was imported from the United States (54 t), Spain (19 t), and Kyrgyzstan (8 t) in 2006 and was used for artisanal gold mining, chlor-alkali production, dental amalgam, or transshipment to other countries in the region. Site visits and interviews provided information on the use and disposition of mercury for artisanal gold mining and other uses. Peru also imports mercury-containing batteries, electronics and computers, fluorescent lamps, and thermometers. In 2006, Peru imported approximately 1,900 t of a wide variety of fluorescent lamps; however, the mercury contained in these lamps, a minimum of approximately 76 kilograms (kg), and in

  11. Structure and function of fish communities in the southern Lake Michigan basin with emphasis on restoration of native fish communities

    Science.gov (United States)

    Simon, Thomas P.; Stewart, Paul M.

    1999-01-01

    The southern Lake Michigan basin in northwest Indiana possesses a variety of aquatic habitats including riverine, palustrine, and lacustrine systems. The watershed draining this area is a remnant of glacial Lake Chicago and supports fish communities that are typically low in species richness. Composition of the presettlement Lake Michigan fish community near the Indiana Dunes has been difficult to reconstruct. Existing data indicate that the number of native species in the Lake Michigan watershed, including nearshore Lake Michigan, has declined by 22% since the onset of European settlement. Few remnants of natural fish communities exist, and those occur principally in the ponds of Miller Woods, the Grand Calumet Lagoons, and the Little Calumet River. These communities have maintained a relatively diverse assemblage of fishes despite large-scale anthropogenic disturbances in the area, including channelization, massive river redirection, fragmentation, habitat alteration, exotic species invasions, and the introduction of toxic chemicals. Data that we collected from 1985 to 1996 suggested that the Grand Calumet River has the highest proportion of exotic fish species of any inland wetland in northwest Indiana. Along the Lake Michigan shoreline, another group of exotics (e.g., round goby, alewife, and sea lamprey) have affected the structure of native fish communities, thereby altering lake ecosystem function. Stocking programs contribute to the impairment of native communities. Nonindigenous species have restructured the function of Lake Michigan tributaries, causing disruptions in trophic dynamics, guild structure, and species diversity. Several fish communities have been reduced or eliminated by the alteration and destruction of spawning and nursery areas. Degradation of habitats has caused an increase in numbers and populations of species able to tolerate and flourish when confronted with hydrologic alteration. Fish communities found on public lands in northwest

  12. Black Mats, Spring-Fed Streams, and Late-Glacial-Age Recharge in the Southern Great Basin

    Science.gov (United States)

    Quade, Jay; Forester, Richard M.; Pratt, William L.; Carter, Claire

    1998-03-01

    Black mats are prominent features of the late Pleistocene and Holocene stratigraphic record in the southern Great Basin. Faunal, geochemical, and sedimentological evidence shows that the black mats formed in several microenvironments related to spring discharge, ranging from wet meadows to shallow ponds. Small land snails such as Gastrocopta tappanianaand Vertigo berryiare the most common mollusk taxa present. Semiaquatic and aquatic taxa are less abundant and include Catinellids, Fossaria parva, Gyraulus parvus,and others living today in and around perennial seeps and ponds. The ostracodes Cypridopsis okeechobiand Scottia tumida,typical of seeps and low-discharge springs today, as well as other taxa typical of springs and wetlands, are common in the black mats. Several new species that lived in the saturated subsurface also are present, but lacustrine ostracodes are absent. The δ 13C values of organic matter in the black mats range from -12 to -26‰, reflecting contributions of tissue from both C 3(sedges, most shrubs and trees) and C 4(saltbush, saltgrass) plants. Carbon-14 dates on the humate fraction of 55 black mats fall between 11,800 to 6300 and 2300 14C yr B.P. to modern. The total absence of mats in our sample between 6300 and 2300 14C yr B.P. likely reflects increased aridity associated with the mid-Holocene Altithermal. The oldest black mats date to 11,800-11,600 14C yr B.P., and the peak in the 14C black mat distribution falls at ˜10,000 14C yr B.P. As the formation of black mats is spring related, their abundance reflects refilling of valley aquifers starting no later than 11,800 and peaking after 11,000 14C yr B.P. Reactivation of spring-fed channels shortly before 11,200 14C yr B.P. is also apparent in the stratigraphic records from the Las Vegas and Pahrump Valleys. This age distribution suggests that black mats and related spring-fed channels in part may have formed in response to Younger Dryas (YD)-age recharge in the region. However, the

  13. Shallow structure of the Chichinautzin Range, southern Mexico basin, central Trans-Mexican Volcanic Belt. A gravity and seismic study

    Science.gov (United States)

    Campos-Enriquez, J. O.; Lermo-Samaniego, J. F.; Antahyua-Vera, Y. T.; Chavacan, M.; Ramón, V. M.; Hernández-García; Pita, C.

    2013-12-01

    Chichinautzin Range (ChR) closes to the S the Mexico Basin (MB). Initially based on height differences between MB and the to-he S-located Morelos Plataform (MP) , a major S-dipping fault was proposed. Depths differences to the limestone basement beneath MB and MP respectively supported its existence. This assumed fault was named La Pera. Earlier studies reported the existence of several faults affecting the ChR. New studies were focused to analyze the cinematic and dynamic character of faults to the W of ChR (Tenango Fault System) and of southern Sierra de la Cruces Range. Also based on a gravity study (Campos-Enríquez et al., 2000), the existence of a major N-dipping fault was inferred to delimit the MB to the S (i.e., delimiting the ChR to the N). Our study is based on gravity modelling, and local seismicity analysis. Accordingly, Mezosoic sandstones above metamorphic rocks constitute the basement underlying ChR. This structural high is faulted to the N and S. To the N, fault blocks displace the basement to larger depths (2-4 km). To the S the basement is shallower. The faults of the gravity model correlate with all reported faults, which collectively are refferred to as Aztlan Fault System. Two N-S MT profiles confirm the model. Several of these faults are associated with seismic activity with a N-S extension and a left-lateral component. The seismic event were located at depths of 7-15 km (i.e. the brittle crust). The system can be traced from the Nevado de Tolca volcano up to the Popocatépetl volcano and even further eastwards. The system is about 200 km long, 30-40 km wide, tectonically active. It enabled the fast emplacement of the ChR volcanic rocs. A flower-type structure was inferred to the S of ChR, further south, the profile is cut by faults belonging either to the Taxco-San Miguel de Allende Fault System or to the Chapala-Oaxaca Fault System. This profile shows how the transpressive tectonics, to the S, accomodates, with the N-S extension affecting

  14. New species and host plants of Anastrepha (Diptera: Tephritidae) primarily from Peru and Bolivia.

    Science.gov (United States)

    Norrbom, Allen L; Rodriguez, Erick J; Steck, Gary J; Sutton, Bruce A; Nolazco, Norma

    2015-11-16

    Twenty-eight new species of Anastrepha are described and illustrated: A. acca (Bolivia, Peru), A. adami (Peru), A. amplidentata (Bolivia, Peru), A. annonae (Peru), A. breviapex (Peru), A. caballeroi (Peru), A. camba (Bolivia, Peru), A. cicra (Bolivia, Peru), A. disjuncta (Peru), A. durantae (Peru), A. echaratiensis (Peru), A. eminens (Peru), A. ericki (Peru), A. gonzalezi (Bolivia, Peru), A. guevarai (Peru), A. gusi (Peru), A. kimi (Colombia, Peru), A. korytkowskii (Bolivia, Peru), A. latilanceola (Bolivia, Peru), A. melanoptera (Peru), A. mollyae (Bolivia, Peru), A. perezi (Peru), A. psidivora (Peru), A. robynae (Peru), A. rondoniensis (Brazil, Peru), A. tunariensis (Bolivia, Peru), A. villosa (Bolivia), and A. zacharyi (Peru). The following host plant records are reported: A. amplidentata from Spondias mombin L. (Anacardiaceae); A. caballeroi from Quararibea malacocalyx A. Robyns & S. Nilsson (Malvaceae); A. annonae from Annona mucosa Jacq. and Annona sp. (Annonaceae); A. durantae from Duranta peruviana Moldenke (Verbenaceae); and A. psidivora from Psidium guajava L. (Myrtaceae).

  15. Tracking the source of mineralisation in the Tampere Basin (southern Finland), insights from structure, sedimentology and geophysics studies

    DEFF Research Database (Denmark)

    Moreau, Julien; Torvela, Taija; Kalliomäki, Henrik;

    2013-01-01

    The ancient basins are of a wide interest to geoscientists as they archive the early development of plate tectonics, life, and ore-bearing systems. Several basins, especially those involving volcanic-derived materials, contain ore and mineral deposits. The formation of these ores is often related...

  16. Layer-block tectonics of Cenozoic basements and formation of intra-plate basins in Nansha micro-plate,southern South China Sea

    Institute of Scientific and Technical Information of China (English)

    LIU Hailing; XIE Guofa; LIN Qiujin; ZHENG Hongbo; LIU Yingchun

    2009-01-01

    Layer-block tectonics (LBT) concept, with the core of pluralistic geodynamic outlook and multi-layer-sliding tectonic outlook, is one of new keys to study 3-dimensional solid and its 4-dimensional evolution history of global tectonic system controlled by global geodynamics system. The LBT concept is applied to study the lithospheric tectonics of the southern South China Sea (SCS). Based on the analysis of about 30 000 km of geophysical and geological data, some layer-blocks in the Nansha micro-plate can be divided as Nansha ultra-crustal layer-block, Zengmu crustal layer-block, Nanwei (Rifleman bank)-Andu (Ardasier bank) and Liyue (Reed bank)-North Palawan crustal layer-blocks, Andu-Bisheng and Liyue-Banyue basemental layer-blocks. The basic characteristics of the basemental layer-blocks have been dicussed, and three intra-plate basin groups are identified. The intra-plate basins within Nansha micro-plate can be divided into three basin groups of Nanwei-Andu, Feixin-Nanhua, and Liyue-North Palawan based on the different geodynamics. In the light of pluralistic geodynamic concept, the upheaving force induced by the mid-crust plastic layer is proposed as the main dynamical force which causes the formation of the intra-plate basins within the Nansha micro-plate. Finally, models of a face-to-face dip-slip-detachment of basemental layer-block and a unilateral dip-slip-detachment of basemental layer-block are put forward for the forming mechanisms of the Nanwei-Andu and Liyue-North Palawan intra-plate basin groups, respectively.

  17. New insight on the water management in Ica Valley-Peru

    Science.gov (United States)

    Guttman, Joseph; Berger, Diego

    2014-05-01

    The Andes divide Peru into three natural drainage basins: Pacific basin, Atlantic basin and Lake Titicaca basin. According to the National Water Authority (ANA), the Pacific basin is the driest basin. The bulk of water that feed the local aquifers in the coastal Pacific region is coming from rivers that flow west from the Andes. One of them is the Ica River- source of the Ica Aquifer and the Pampas de Villacuri Aquifer. The Ica River flows in a graben that was created by a series of faults. The graben is filled with sand and gravel with interbeded and lenses of clay. The aquifer thickness varies between 25 meters to more than 200 meters. The Ica Valley has an extension of 7700 km2 and belongs to the Province of Ica, the second larger economic center in Peru. The Valley is located in the hyperarid region of the Southern Coastal area of Peru with a few millimeters of precipitation per year. The direct recharge is almost zero. The recharge into the Ica Valley aquifer is comes indirectly by infiltration of storm water through the riverbed generates in the Andes, through irrigation canals and by irrigation return flow. In this hyperarid region, local aquifers like the Ica Valley are extremely valuable resources to local populations and are the key sources of groundwater for agriculture and population needs. Therefore, these aquifers play a crucial role in providing people with water and intense attention should be given to manage the water sector properly and to keep the aquifer sustainable for future generations. The total pumping (from rough estimations) is much greater than the direct and indirect recharge. The deficit in the water balance is reflected in large water level decline, out of operation of shallow wells and the ascending of saline water from deeper layers. The change from flood irrigation that contributes about 35-40% of the water to the aquifer, to drip irrigation dramatically reduces the amount of water that infiltrates into the sub-surface from the

  18. Geochemical characteristics and genetic types of crude oils from the Tertiary system in the southern part of western Qaidam Basin, Northwest China

    Institute of Scientific and Technical Information of China (English)

    LI Hongbo; ZHANG Min; ZHANG Chunming; PENG Dehua

    2008-01-01

    Crude oil samples taken from the southern part of westem Qaidam Basin were analyzed with GC/MS in order to understand the geochemical characteristics of crude oils. The results reveal that most crude oils are characterized by high abundance of gammaeerane and C35 homohopane, which are the representative characteristics of saline lacustrine crude oils. Based on the variation of the ratios of gammacerane/C30 hopane (G/H) and C35 homohopane/C34 homohopane (C35/C34H), two crude oil groups, A and B, are identified. Group-A crude oils mainly occurr in the north of the study area, with higher ratios of G/H (>0.8) and C35/C34H (>1.2), whereas group-B crude oils, selected from the south of the study area, show lower ratios of G/H (<0.8) and C35/C3aH (<1.0). In addition, group-A crude oils are distinguished into three subgroups in accordance with their different ratios of G/H and C35/C34H and different distribution characteristics of n-alkanes, isoprenoids and steranes. These may be helpful for understanding the distribution characteristics of crude oils in the southern part of western Qaidam Basin and providing clues to the forthcoming exploration of crude oils and gas.

  19. The role of internal waves in the formation of layered structure at exchange flows between two closed basins (Middle and southern basins of the Caspian sea

    Directory of Open Access Journals (Sweden)

    A. A. Bidokhti

    2005-12-01

    Full Text Available  Layered structures in the oceans have always attracted the attention of oceanographers. The formation of these structures have been attributed to phenomena such as double – diffusive convection, internal waves and turbulent modulated mixing .In this paper, the vertical structures of temperature, salinity, density and the layered structure in the middle parts of Caspian Sea have been studied. Counters of iso-quantities of these physical properties, show the existence of regular structures, which indicate that internal waves which are produced by exchanging flow between two basins, as a result of horizontal density gradients (usually from north basin to south basin may generate these layers. Froude number of this flow is about one. The length of wave of the internal waves is found to be about 200 km and the flow velocity associated with this gravity drive flow is about 0.2 m/s, the frequency of these waves is of order of inertial frequency. The normal modes of these waves have a near steady structure and can fold the inflow front from the North Caspian sea to South Caspian Sea basins, then the layered structure are formed. The thickness of these layers so formed is found to be about 10-20 m. These are in agreement with the values predicted by the model of Wong et al, (2001. In these waters density ratio is negative. Thus, double – diffusive convection does not often happen and cannot produce these layered structures.

  20. The Arequipa (Peru) earthquake of June 23, 2001

    Science.gov (United States)

    Tavera, H.; Buforn, E.; Bernal, I.; Antayhua, Y.; Vilacapoma, L.

    The Arequipa earthquake of 23 June 2001 hasbeen the largest earthquake (Mw = 8.3)occurredin the last century in southern Peru with amaximum intensity of VIII (MM scale). Focalmechanisms of main shock and three largeraftershocks have been studied, showingthrusting solutions for main shock and twoaftershocks and normal motion for the eventof July, 5. The rupture area has beenobtained from distribution of aftershocks.The occurrence of the Arequipa earthquakeis related with the convergence processbetween the Nazca and South Americaplates.

  1. Optica Precolombina Del Peru

    CERN Document Server

    Lunazzi, J J

    2007-01-01

    Archaeological American mirrors are common findings and the images obtained with them are often described by archaeologists as possessing high quality. However, photographs attesting this fact are rare, if any. To the best of my knowledge, only two papers show that quality concerning the Olmeca culture, and only one of them mentions the pre-Inca cultures case. Certainly more images are needed to increase awareness of the importance of the existence of sophisticated imaging elements, particularly when evaluating the cultural degree of the pre-Columbian civilizations. In this paper we show images made in two museums in Lima, Peru, by means of mirrors and the lens action on a necklace element.

  2. Peru; Recent Economic Developments

    OpenAIRE

    International Monetary Fund

    1996-01-01

    This paper describes economic developments in Peru during the 1990s. During 1990–92, real GDP growth was negative by 0.9 percent a year on average, reflecting in part deterioration in the terms of trade and adverse weather conditions. During that period, growth in the construction, manufacturing, and fishing sectors was more than offset by a contraction in the agricultural and mining sectors. Gross domestic investment rose from about 15½ percent of GDP in 1990 to 16½ percent in 1992 mainl...

  3. Selected examples of needs for long term pilot areas in Mediterranean catchments: a mountain traditional agricultural system and a large and regulated hydrographic basin in Southern Spain

    Science.gov (United States)

    José Polo, María; Herrero, Javier; Millares, Agustín; José Pérez-Palazón, María; Pimentel, Rafael; Aguilar, Cristina; Jurado, Alicia; Contreras, Eva; Gómez-Beas, Raquel; Carpintero, Miriam; Gulliver, Zacarías

    2015-04-01

    Integrated River Basin Management (IRBM) aims at planning water, land and other natural resources for an equitable and sustainable management, also capable of preserving or restoring freshwater ecosystems. Long term series of significant variables at different scales and a sound knowledge of the river basin processes are needed to establish the current state and past&future evolution of the hydrological system, soil use and vegetation distribution, and their social impacts and feedbacks. This is particularly crucial if future scenario analyses are to be performed to assess decision-making processes and adaptive plans. This work highlights the need for an adequate design and development of process-oriented monitoring systems at the basin scale in a decision-making framework. First, the hydrologic monitoring network of the Guadalfeo River Basin, in the southern face of Sierra Nevada Range (Spain), is shown, in a pilot catchment of 1300 km2 in which snow processes in Mediterranean conditions have been studied over the last ten years with a holistic approach. The network development and the main features of the dataset are described together with their use for different scientific and environmental applications; their benefits for assessing social and economic impact in the rural environment are shown from a study case in which the sustainability of ancient channels fed by snowmelt, in use since the XIIIth century for traditional irrigated crops in the mountainous area, was assessed in a future scenarios analyses. Secondly, the standard flow and water quality monitoring networks in the Guadalquivir River Basin, a large (57400 km2) and highly regulated agricultural catchment in southern Spain, are shown, and their strengths and weaknessess for an IRBM framework are analysed. Sediments and selected pollutants are used to trace soil erosion and agricultural/urban exports throughout the catchment, and the final loads to the river estuary in the Atlantic Ocean are assessed

  4. ENSO impact on hydrology in Peru

    Science.gov (United States)

    Lavado-Casimiro, W. S.; Felipe, O.; Silvestre, E.; Bourrel, L.

    2013-04-01

    The El Niño and La Niña impacts on the hydrology of Peru were assessed based on discharge data (1968-2006) of 20 river catchments distributed over three drainage regions in Peru: 14 in the Pacific Coast (PC), 3 in the Lake Titicaca (TL) region, and 3 in the Amazonas (AM). To classify the El Niño and La Niña events, we used the Southern Oscillation Index (SOI) based on hydrological years (September to August). Using the SOI values, the events were re-classified as strong El Niño (SEN), moderate El Niño (MEN), normal years (N), moderate La Niña (MLN) and strong La Niña (SLN). On average during the SEN years, sharp increases occurred in the discharges in the north central area of the PC and decreases in the remaining discharge stations that were analyzed, while in the years of MEN events, these changes show different responses than those of the SEN. During the years classified as La Niña, positive changes are mostly observed in the majority of the stations in the rivers located in the center of Peru's Pacific Coast. Another important result of this work is that the Ilave River (south of the Titicaca watershed) shows higher positive (negative) impacts during La Niña (El Niño) years, a fact that is not clearly seen in the rivers of the northern part of the Titicaca watershed (Ramis and Huancane rivers).

  5. Detrital Zircon Provenance Record of Pre-Andean to Modern Tectonics in the Northern Andes: Examples from Peru, Ecuador, and Colombia

    Science.gov (United States)

    George, S. W. M.; Jackson, L. J.; Horton, B. K.

    2015-12-01

    Detrital zircon U-Pb age distributions from modern rivers and Mesozoic-Cenozoic basin fill in the northern Andes provide insights into pre-Andean, Andean, and active uplift and exhumation of distinctive sediment source regions. Diagnostic age signatures enable straightforward discrimination of competing sediment sources within the Andean magmatic arc (Western Cordillera-Central Cordillera), retroarc fold-thrust belt (Eastern Cordillera-Subandean Zone), and Amazonian craton (composed of several basement provinces). More complex, however, are the mid/late Cenozoic provenance records generated by recycling of basin fill originally deposited during early/mid Mesozoic extension, late Mesozoic thermal subsidence, and early Cenozoic shortening. Although subject to time-transgressive trends, regionally significant provenance patterns in Peru, Ecuador, and Colombia reveal: (1) Triassic-Jurassic growth of extensional subbasins fed by local block uplifts (with commonly unimodal 300­-150 Ma age peaks); (2) Cretaceous deposition in an extensive postrift setting fed by principally cratonic sources (with common 1800-900 Ma ages); and (3) Cenozoic growth of a broad flexural basin fed initially fed by magmatic-arc rocks (100-0 Ma), then later dominance by thrust-belt sedimentary rocks with progressively greater degrees of basin recycling (yielding diverse and variable age populations from the aforementioned source regions). U-Pb results from modern rivers and smaller subbasins prove useful in evaluating source-to-sink relationships, downstream mixing relationships, hinterland-foreland basin connectivity, paleodrainage integration, and tectonic/paleotopographic reconstructions. Most but not all of the elevated intermontane basins in the modern hinterland of the northern Andes contain provenance records consistent with genesis in a broader foreland basin developed at low elevation. Downstream variations within modern axial rivers and Cenozoic axial basins inform predictive models of

  6. Detection of detached forced-regressive nearshore wedges: a case study from the central-southern Siena Basin (Northern Apennines, Italy)

    Science.gov (United States)

    Martini, Ivan; Arragoni, Simone; Aldinucci, Mauro; Foresi, Luca Maria; Bambini, Anna Maria; Sandrelli, Fabio

    2013-07-01

    The detection of detached nearshore wedges formed in response to relative sea-level drops is considered one of the hottest topics in sequence stratigraphic analysis due to their importance as reservoir analogues. In fact, they usually constitute sandy and porous bodies generally encased in impermeable clay, thus presenting a good potential as traps for fluids. This paper focuses on the sequence stratigraphic analysis of the Pliocene deposits cropping out in the central-southern sector of the Siena Basin (Tuscany, Italy), a post-collisional basin of the Northern Apennines. The exposed sedimentary succession was investigated through a detailed sedimentological and stratigraphic approach, integrated by biostratigraphic analyses, aimed at a better characterization of the infilling history of this sector of the basin. Specifically, this study revealed the occurrence of repeated facies shifts that allowed the identification of two depositional sequences. In detail, a thick sand-rich body far from the basin margins, and previously considered as a turbiditic lobe, has been reinterpreted as formed in a nearshore setting during a fall in relative sea level. This body is totally encased in offshore clay, and due to the lack of physical connection with the related HST deposits, it has to be considered as a detached forced-regressive wedge. The present work led to the recognition of some sedimentological and stratigraphic features typical of falling stage systems tract deposits (e.g. presence of intrabasinal recycled materials, sedimentological evidence of a pre-existing fluvial network subsequently eroded) that can provide useful clues for the identification of detached forced-regressive nearshore wedges in core studies and poorly exposed settings.

  7. Astrology in seventeenth-century Peru.

    Science.gov (United States)

    Brosseder, Claudia

    2010-06-01

    This article discusses three aspects of the history of astrology in seventeenth-century Peru that are of larger interest for the history of science in Latin America: Creole concerns about indigenous idolatry, the impact of the Inquisition on natural philosophy, and communication between scholars within the Spanish colonies and the transatlantic world. Drawing mainly on the scholars Antonio de la Calancha, Juan de Figueroa, and Ruiz de Lozano, along with several Jesuits, the article analyzes how natural and medical astrology took shape in Peru and how they fostered astronomical investigations of the southern skies. While natural and medical astrology, showing New and Old World influences, oscillated between orthodoxy and heterodoxy, and between scholasticism and new science, judicial astrology remained undeveloped. Toward the end of the seventeenth century the discourse about astrology took an unexpected turn, reflecting a newly invigorated moral and Christian reading of the heavens that was in part a response to a deep-rooted dissatisfaction with the failure of the extirpation of idolatry campaigns. Inscribing divine and cardinal virtues, the Virgin Mary, Christian saints, and Greco-Roman allegories into the heavens was considered a way to finally solve the problem of idolatry and to convey Creole greatness. PMID:20513626

  8. Astrology in seventeenth-century Peru.

    Science.gov (United States)

    Brosseder, Claudia

    2010-06-01

    This article discusses three aspects of the history of astrology in seventeenth-century Peru that are of larger interest for the history of science in Latin America: Creole concerns about indigenous idolatry, the impact of the Inquisition on natural philosophy, and communication between scholars within the Spanish colonies and the transatlantic world. Drawing mainly on the scholars Antonio de la Calancha, Juan de Figueroa, and Ruiz de Lozano, along with several Jesuits, the article analyzes how natural and medical astrology took shape in Peru and how they fostered astronomical investigations of the southern skies. While natural and medical astrology, showing New and Old World influences, oscillated between orthodoxy and heterodoxy, and between scholasticism and new science, judicial astrology remained undeveloped. Toward the end of the seventeenth century the discourse about astrology took an unexpected turn, reflecting a newly invigorated moral and Christian reading of the heavens that was in part a response to a deep-rooted dissatisfaction with the failure of the extirpation of idolatry campaigns. Inscribing divine and cardinal virtues, the Virgin Mary, Christian saints, and Greco-Roman allegories into the heavens was considered a way to finally solve the problem of idolatry and to convey Creole greatness.

  9. The flux and recovery of bioactive substances in the surface sediments of deep basins off southern California

    Energy Technology Data Exchange (ETDEWEB)

    Jahnke, R.A.

    1990-06-11

    Sediment microbial community biomass and activity in Santa Monica Basin, a nearshore basin in the California Continental Borderland, were examined in October 1985, 1986 and 1987, May 1986, April 1987 and January 1990. Millimeter-scale ATP profiles and incubation of intact cores with {sup 3}H-adenine indicated a high-biomass interface microbial population in the low-oxygen central basin, which was absent in samples from the basin slope sediments. A majority of microbial activity and organic matter mineralization occurred in the top cm of sediment. Comparison of measured ATP and total organic carbon profiles suggest that the C:ATP ratio (wt:wt) ranges between 47:1 and 77:1 in central basin interfacial populations, substantially lower than reported for other aquatic environments. Carbon production estimated from DNA synthesis measurements via {sup 3}H-adenine incorporation was compared with TCO{sub 2} fluxes measured by in situ benthic chamber experiments. Within the uncertainty of the C:ATP ratio, an overall microbial carbon assimilation efficiency of 75--90% was indicated. The low C:ATP ratios and high carbon assimilation efficiencies significantly affect estimates of microbial growth and respiration and are substantially different than those often assumed in the literature. These results suggest that without independent knowledge of these ratios, the uncertainty in tracer-derived microbial growth and respiration rates may be larger than previously reported. 66 refs., 8 figs., 3 tabs.

  10. Integrated modelling and management of nutrients and eutrophication in river basin - coast - sea systems: A southern Baltic Sea perspective

    Science.gov (United States)

    Schernewski, Gerald

    2014-05-01

    The Odra river basin (area: 120,000 km2, average discharge: 550 m³/s, annual N-load 60,000 t) and the Oder (Szczecin) Lagoon (687 km²) are the eutrophication hot-spot in the south-western Baltic region. To be able to carry out large scale, spatially integrative analyses, we linked the river basin nutrient flux model MONERIS to the coastal 3D-hydrodynamic and ecosystem model ERGOM. Objectives were a) to analyse the eutrophication history in the river basin and the resulting functional changes in the coastal waters between early 1960's and today and b) to analyse the effects of nitrogen and phosphorus management scenarios in the Oder/Odra river basin on coastal and Baltic Sea water quality. The models show that an optimal river basin management with reduced nutrient loads (e.g. N-load reduction of 35%) would have positive effects on lagoon water quality and algae biomass. The availability of nutrients, N/P ratios and processes like denitrification and nitrogen-fixation would show spatial and temporal changes. It would have positive consequences for ecosystems functions, like the nutrient retention capacity, as well. However, this optimal scenario is by far not sufficient to ensure a good coastal water quality according to the European Water Framework Directive. A "good" water quality in the river will not be sufficient to ensure a "good" water quality in the coastal waters. Further, nitrogen load reductions bear the risk of increased potentially toxic, blue-green algae blooms. The presentation will a) summarize recent results (Schernewski et al. 2009, Schernewski et al. 2011, 2012), b) give an overview how the models were used to provide a comprehensive and consistent set of water quality thresholds and maximum allowable riverine loads for the Water Framework Directive and c) will show the implications for an optimised river basin - lagoon quality management.

  11. Quatro especies nuevas de nematodos del sur del Perú y redescripción de Hedruris Orestiae Moniez, 1889 Four new species of nematodes from southern Peru, with a redescription of Hedruris orestiae Moniez, 1889

    Directory of Open Access Journals (Sweden)

    Nicanor Ibâñez H.

    1976-01-01

    Full Text Available En el estudio helmintológico de anfibios del género Telmatobius Wiegmann, 1834, y del pez Orestias luteus Valenciennes, 1839, de las zonas de Arequipa, Puno y del Lago Titicaca, se han encontrado nematodes de los géneros Hedruris Nitzsch, 1821 y Falcaustra Lane, 1915. Se redescribe Hedruris orestiae Moniez, 1889 y se describen cuatro especies nuevas: Hedruris moniezi sp. n., Falcaustra condorcanquii sp. n., Falcaustra pumacahuai sp. n. y Falcaustra tiahuanaquensis sp. n.The collection of large numbers of nematodes from amphibians (Telmatobius sp. and fish Orestias luteus Valenciennes, 1839 Arequipa, Puno, and Titicaca Lake in South Peru has made possible the revision of one species and the description of our new species: Hedruris orestiae Moniez, 1889 is re-described; Hedruris moniezi sp. n., Falcaustra condorcanquii sp. n., Falcaustra pumacahuai sp. and Falcaustra tiahuanaquensis sp. n. are described.

  12. Gravity sliding in basinal setting, a surficial record of tectonic and geodynamic evolution; examples from the southern W. Alps and their foreland

    Science.gov (United States)

    Dumont, T.; Franzi, V.; Matthews, S. J.

    2012-04-01

    The occurrence of large-scale submarine landslides, although commonly observed in the present basins, is only exceptionally mentioned in the Alpine orogen and foreland. The southern part of the Western Alpine arc and the SE basin of France provide examples of such features which could be related with particular geodynamic events, in relation with the motion of the Iberian and Adriatic microplates : - A >50km2 slump scar formed in Aptian times at the northwestern edge of the SE France (so-called Vocontian) basin, giving a low-angle detachment surface which was onlapped by Albian hemipelagic marls (Ferry & Flandrin, 1979). The latter mark the maximum deepening stage of the basin, and the head of the scar is located over a deep-seated fault bounding the platform, which strongly suggest that sliding was caused by differential subsidence due to Middle Cretaceous extension, as a consequence of Iberia-Europe divergence. - Later on, a deep-marine erosion surface developed further down the basin over a >100km2 area (Dévoluy massif; Michard et al., 2010), which had been previously affected by Mid-Cretaceous extension. Typical inversion structures are found beneath the surface, which indicate that NS shortening overprinted the extensional pattern. The removal of up to 400m of Mesozoic sediments was controlled by gravity processes, probably triggered by the deformation of the basin floor following tectonic inversion. The overlying pelagic carbonates indicate that shortening occurred before the Campanian, which is closely comparable with the earliest stages of tectonic inversion in the Pyrenees. - The transition slope between the Paleogene Alpine flexural basin and the NW-ward propagating accretionary prism provides examples of basin floor degradation and of gravity-driven emplacement of large-scale blocks, generally regarded as thrust-sheets in the Alps. These features allow to reconstruct the early stages of the Adria-Europe collision, which strongly differ from the Oligo

  13. Inhalants in Peru.

    Science.gov (United States)

    Lerner, R; Ferrando, D

    1995-01-01

    In Peru, the prevalence and consequences of inhalant abuse appear to be low in the general population and high among marginalized children. Inhalant use ranks third in lifetime prevalence after alcohol and tobacco. Most of the use appears to be infrequent. Among marginalized children, that is, children working in the streets but living at home or children living in the street, the problem of inhalant abuse is a serious problem. Among children working in the streets but living at home, the lifetime prevalence rate for inhalant abuse is high, ranging from 15 to 45 percent depending on the study being cited. For children living in the streets, the use of inhalant is even more severe. As mentioned earlier in this chapter, most of these street children use inhalants on a daily basis. The lack of research on the problem of inhalant abuse is a serious impediment to development of intervention programs and strategies to address this problem in Peru. Epidemiologic and ethnographic research on the nature and extent of inhalant abuse are obvious prerequisites to targeted treatment and preventive intervention programs. The urgent need for current and valid data is underscored by the unique vulnerability of the youthful population at risk and the undisputed harm that results from chronic abuse of inhalants. Nonetheless, it is important to mention several programs that work with street children. Some, such as the Information and Education Center for the Prevention of Drug Abuse, Generation, and Centro Integracion de Menores en Abandono have shelters where street children are offered transition to a less marginal lifestyle. Teams of street educators provide the children with practical solutions and gain their confidence, as well as offer them alternative socialization experiences to help them survive the streets and avoid the often repressive and counterproductive environments typical of many institutions. Most of the children who go through these programs tend to abandon

  14. Crustal structures across Canada Basin and southern Alpha Ridge of the Arctic Ocean from P- and S-wave sonobuoy wide-angle studies

    Science.gov (United States)

    Chian, D.; Shimeld, J.; Jackson, R.; Hutchinson, D. R.; Mosher, D. C.

    2010-12-01

    During 2007-2009, a total of 127 expendable sonobuoys (SB) were deployed across Canada Basin and southern Alpha Ridge to record wide-angle reflections and refractions from more than 10,000 km of inline, short-offset seismic reflection surveying. Most of the SB data show clear wide-angle refractions/reflections from various sedimentary and crustal layers at offsets up to 35 km. Source-receiver offsets are calculated using direct water waves. Subsequent processing includes compensation for spherical divergence and attenuation, despiking, filtering, deconvolution, and NMO correction. During wide-angle modeling, inline reflection data are converted to depth using velocity models/interpretations, iteratively updated based on wide-angle raytracing. Slight ray angle dependent anisotropy is found to best describe observed data, and is used for time-depth conversions. Clear deep refractions from upper, middle and lower crusts are recorded by most SB. Across southern Canada Basin, a regionally consistent velocity structure exists: velocities of ~4.5 km/s overlie a sub-basement layer of 5.5-5.8 km/s at depths of 12-13 km which, in turn, overlie a lower crust of 6.7-7.2 km/s. This structure is intersected by a central gravity low (previously interpreted to be an extinct spreading center), west of which the basement and sub-basement layers are consistently shallower by >1 km than the eastern side. Further northward, significant velocity variations exist. For example, the southern Alpha Ridge has a lower crust of 6.0-6.6 km/s or 6.8-7.0 km/s. Volcanic intrusions, inferred from high basement velocities of ~5.7 km/s at unusually shallow depths (~5 km), exist at discrete locations along southern Alpha Ridge. Between Northwind Ridge and Alpha Ridge, a typical continent-type crustal structure is observed. PmP is occasionally observed, modeling of which results in a Moho depth of 12-15 km. Velocities of 4.2-4.5 km/s in the northern study area are associated with a regional

  15. Identification and simulation of space–time variability of past hydrological drought events in the Limpopo River basin, southern Africa

    NARCIS (Netherlands)

    Trambauer, P.; Maskey, S.; Werner, M.; Pappenberger, F.; Van Beek, L.P.H.; Uhlenbrook, S.

    2014-01-01

    Droughts are widespread natural hazards and in many regions their frequency seems to be increasing. A finer-resolution version (0.05° × 0.05°) of the continental-scale hydrological model PCRaster Global Water Balance (PCR-GLOBWB) was set up for the Limpopo River basin, one of the most water-stressed

  16. Assessment of undiscovered copper resources associated with the Permian Kupferschiefer, Southern Permian Basin, Europe: Chapter U in Global mineral resource assessment

    Science.gov (United States)

    Zientek, Michael L.; Oszczepalski, Sławomir; Parks, Heather L.; Bliss, James D.; Borg, Gregor; Box, Stephen E.; Denning, Paul D.; Hayes, Timothy S.; Spieth, Volker; Taylor, Cliff D.

    2015-01-01

    This study synthesizes available information and estimates the location and quantity of undiscovered copper associated with a late Permian bituminous shale, the Kupferschiefer, of the Southern Permian Basin in Europe. The purpose of this study is to (1) delineate permissive areas (tracts) where undiscovered reduced-facies sediment-hosted stratabound copper deposits could occur within 2.5 kilometers of the surface, (2) provide a database of known reduced-facies-type sediment-hosted stratabound copper deposits and significant prospects, and (3) provide probabilistic estimates of amounts of undiscovered copper that could be present within each tract. This assessment is a contribution to a global assessment conducted by the U.S. Geological Survey (USGS).

  17. Tectono-thermal History of the Southern Nenana Basin, Interior Alaska: Implications for Conventional and Unconventional Hydrocarbon Exploration

    Science.gov (United States)

    Dixit, N. C.; Hanks, C. L.

    2014-12-01

    The Tertiary Nenana basin of Interior Alaska is currently the focus of both new oil exploration and coalbed methane exploitation and is being evaluated as a potential CO2sequestration site. The basin first formed as a Late Paleocene extensional rift with the deposition of oil and gas-prone, coal-bearing non-marine sediments with excellent source potential. Basin inversion during the Early Eocene-Early Oligocene times resulted in folding and erosion of higher stratigraphic levels, forming excellent structural and stratigraphic traps. Initiation of active faulting on its eastern margin in the middle Oligocene caused slow tectonic subsidence that resulted in the deposition of reservoir and seal rocks of the Usibelli Group. Onset of rapid tectonic subsidence in Pliocene that continues to the present-day has provided significant pressure and temperature gradient for the source rocks. Apatite fission-track and vitrinite reflectance data reveals two major paleo-thermal episodes: Late Paleocene to Early Eocene (60 Ma to 54.8 Ma) and Late Miocene to present-day (7 Ma to present). These episodes of maximum paleotemperatures have implications for the evolution of source rock maturity within the basin. In this study, we are also investigating the potential for coalbed methane production from the Late Paleocene coals via injection of CO2. Our preliminary analyses demonstrate that 150 MMSCF of methane could be produced while 33000 tonnes of CO2 per injection well (base case of ~9 years) can be sequestered in the vicinity of existing infrastructure. However, these volumes of sequestered CO2and coal bed methane recovery are estimates and are sensitive to the reservoir's geomechanical and flow properties. Keywords: extensional rift, seismic, subsidence, thermal history, fission track, vitrinite reflectance, coal bed methane, Nenana basin, CO2 sequestration

  18. Identification and simulation of space-time variability of past hydrological drought events in the Limpopo river basin, Southern Africa

    Directory of Open Access Journals (Sweden)

    P. Trambauer

    2014-03-01

    droughts in the Limpopo river basin in the period 1979–2010 with a view to identifying severe droughts that have occurred in the basin. Evaporation, soil moisture, groundwater storage and runoff estimates from the model were derived at a spatial resolution of 0.05° (approximately 5 km on a daily time scale for the entire basin. PCR-GLOBWB was forced with daily precipitation, temperature and other meteorological variables obtained from the ERA-Interim global atmospheric reanalysis product from the European Centre for Medium-Range Weather Forecasts. Two agricultural drought indicators were computed: the Evapotranspiration Deficit Index (ETDI and the Root Stress Anomaly Index (RSAI. Hydrological drought was characterised using the Standardized Runoff Index (SRI and the Groundwater Resource Index (GRI, which make use of the streamflow and groundwater storage resulting from the model. Other more widely used drought indicators, such as the Standardized Precipitation Index (SPI and the Standardized Precipitation Evaporation Index (SPEI were also computed for different aggregation periods. Results show that a carefully set up process-based model that makes use of the best available input data can successfully identify hydrological droughts even if the model is largely uncalibrated. The indicators considered are able to represent the most severe droughts in the basin and to some extent identify the spatial variability of droughts. Moreover, results show the importance of computing indicators that can be related to hydrological droughts, and how these add value to the identification of droughts/floods and the temporal evolution of events that would otherwise not have been apparent when considering only meteorological indicators. In some cases, meteorological indicators alone fail to capture the severity of the drought. Therefore, a combination of some of these indicators (e.g. SPEI-3, SRI-6, SPI-12 is found to be a useful measure for identifying hydrological droughts in

  19. Serological evidence for Saint Louis encephalitis virus in free-ranging New World monkeys and horses within the upper Paraná River basin region, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Walfrido Kühl Svoboda

    2014-06-01

    Full Text Available Introduction Saint Louis encephalitis virus (SLEV primarily occurs in the Americas and produces disease predominantly in humans. This study investigated the serological presence of SLEV in nonhuman primates and horses from southern Brazil. Methods From June 2004 to December 2005, sera from 133 monkeys (Alouatta caraya, n=43; Sapajus nigritus, n=64; Sapajus cay, n=26 trap-captured at the Paraná River basin region and 23 blood samples from farm horses were obtained and used for the serological detection of a panel of 19 arboviruses. All samples were analyzed in a hemagglutination inhibition (HI assay; positive monkey samples were confirmed in a mouse neutralization test (MNT. Additionally, all blood samples were inoculated into C6/36 cell culture for viral isolation. Results Positive seroreactivity was only observed for SLEV. A prevalence of SLEV antibodies in sera was detected in Alouatta caraya (11.6%; 5/43, Sapajus nigritus (12.5%; 8/64, and S. cay (30.8%; 8/26 monkeys with the HI assay. Of the monkeys, 2.3% (1/42 of A. caraya, 6.3% 94/64 of S. nigritus, and 15.4% (4/26 of S. cay were positive for SLEV in the MNT. Additionally, SLEV antibodies were detected by HI in 39.1% (9/23 of the horses evaluated in this study. Arboviruses were not isolated from any blood sample. Conclusions These results confirmed the presence of SLEV in nonhuman primates and horses from southern Brazil. These findings most likely represent the first detection of this virus in nonhuman primates beyond the Amazon region. The detection of SLEV in animals within a geographical region distant from the Amazon basin suggests that there may be widespread and undiagnosed dissemination of this disease in Brazil.

  20. Web application to access U.S. Army Corps of Engineers Civil Works and Restoration Projects information for the Rio Grande Basin, southern Colorado, New Mexico, and Texas

    Science.gov (United States)

    Archuleta, Christy-Ann M.; Eames, Deanna R.

    2009-01-01

    The Rio Grande Civil Works and Restoration Projects Web Application, developed by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers (USACE) Albuquerque District, is designed to provide publicly available information through the Internet about civil works and restoration projects in the Rio Grande Basin. Since 1942, USACE Albuquerque District responsibilities have included building facilities for the U.S. Army and U.S. Air Force, providing flood protection, supplying water for power and public recreation, participating in fire remediation, protecting and restoring wetlands and other natural resources, and supporting other government agencies with engineering, contracting, and project management services. In the process of conducting this vast array of engineering work, the need arose for easily tracking the locations of and providing information about projects to stakeholders and the public. This fact sheet introduces a Web application developed to enable users to visualize locations and search for information about USACE (and some other Federal, State, and local) projects in the Rio Grande Basin in southern Colorado, New Mexico, and Texas.

  1. Modified Gulf of California model for South Georgia,north Scotia Ridge, and implications for the Rocas Verdes back-arc basin, southern Andes

    Science.gov (United States)

    Alabaster, T.; Storey, B. C.

    1990-06-01

    New field mapping and an integrated trace element and Nd isotopic study have been undertaken on the Jurassic-Cretaceous Larsen Harbour Complex on the island of South Georgia, recognized as a displaced part of the southern Andes ensialic, autochthonous Rocas Verdes marginal basin. Five basalt groups (Groups I-V) are identified from trace element data; initial Nd isotopic compositions suggest that they are derived from only two sources. Magmas produced during early stages of continental lithospheric attenuation (Groups I-III) were derived by varying degrees of partial melting and fractional crystallization from a large ion lithophile element (LILE)-enriched, low-ɛNd mantle source relative to normal (N)-type mid-ocean ridge basalt (MORB). Magmas produced during later stages of rifting (Groups IV and V) were, however, derived from a high-ɛNd asthenospheric mantle source similar to N-type MORB, unaffected by earlier LILE enrichment. Our data do not concur with previous suggestions that the Larsen Harbour Complex and, by implication, the Rocas Verdes formed in a supra-subduction-zone setting. On the basis of geologic and geochemical evidence, we favor basin formation along an oblique-slip margin akin to that of the Gulf of California.

  2. Web Application to Access U.S. Army Corps of Engineers Civil Works and Restoration Projects Information for the Rio Grande Basin, Southern Colorado, New Mexico, and Texas

    Science.gov (United States)

    Archuleta, Christy-Ann M.; Eames, Deanna R.

    2009-01-01

    The Rio Grande Civil Works and Restoration Projects Web Application, developed by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers (USACE) Albuquerque District, is designed to provide publicly available information through the Internet about civil works and restoration projects in the Rio Grande Basin. Since 1942, USACE Albuquerque District responsibilities have included building facilities for the U.S. Army and U.S. Air Force, providing flood protection, supplying water for power and public recreation, participating in fire remediation, protecting and restoring wetlands and other natural resources, and supporting other government agencies with engineering, contracting, and project management services. In the process of conducting this vast array of engineering work, the need arose for easily tracking the locations of and providing information about projects to stakeholders and the public. This fact sheet introduces a Web application developed to enable users to visualize locations and search for information about USACE (and some other Federal, State, and local) projects in the Rio Grande Basin in southern Colorado, New Mexico, and Texas.

  3. Microfacies analysis of the Upper Triassic (Norian) "Bača Dolomite": early evolution of the western Slovenian Basin (eastern Southern Alps, western Slovenia)

    Science.gov (United States)

    Gale, Luka

    2010-08-01

    The Slovenian Basin represents a Mesozoic deep-water sedimentary environment, situated on the southern Tethyan passive margin. Little is known about its earliest history, from the initial opening in the Carnian (probably Ladinian) to a marked deepening at the beginning of the Jurassic. The bulk of the sediment deposited during this period is represented by the Norian-Rhaetian "Bača Dolomite", which has, until now, been poorly investigated due to a late-diagenetic dolomitization. The Mount Slatnik section (south-eastern Julian Alps, western Slovenia) is one of a few sections where the dolomitization was incomplete. Detailed analysis of this section allowed us to recognize eight microfacies (MF): MF 1 (calcilutite), MF 2 (pelagic bivalve-radiolarian floatstone/wackestone to rudstone/packstone), MF 3 (dolomitized mudstone) with sub-types MF 3-LamB and MF 3-LamD (laminated mudstone found in a breccia matrix and laminated mudstone found in thin-bedded dolomites, respectively) and MF 3-Mix (mixed mudstone), MF 4 (bioturbated radiolarian-spiculite wackestone), MF 5 (fine peloidal-bioclastic packstone), MF 6 (very fine peloidal packstone), MF 7 (bioclastic wackestone) and MF 8 (crystalline dolomite). The microfacies and facies associations indicate a carbonate slope apron depositional environment with hemipelagic sedimentation punctuated by depositions from turbidites and slumps. In addition to the sedimentary environment, two "retrogradation-progradation" cycles were recognized, each with a shift of the depositional setting from an inner apron to a basin plain environment.

  4. First record of Lophodinium polylophum (Daday Lemmermann 1910 (Dinophyceae: Lophodiniaceae in Peru

    Directory of Open Access Journals (Sweden)

    Iris Samanez

    2015-04-01

    Full Text Available Herein, the first record of Lophodinium polylophum from Peru is presented. This fresh water dinoflagellate was identified in plankton samples from the lagoon Picoplancha of Santuario Nacional Pampas del Heath (Madre de Dios and from a stream in the Puinahua River basin in Loreto.

  5. Fault-Related CO2 Degassing, Geothermics, and Fluid Flow in Southern California Basins--Physiochemical Evidence and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Garven, Grant [Tufts University

    2015-08-11

    Our studies have had an important impact on societal issues. Experimental and field observations show that CO2 degassing, such as might occur from stored CO2 reservoir gas, can result in significant stable isotopic disequilibrium. In the offshore South Ellwood field of the Santa Barbara channel, we show how oil production has reduced natural seep rates in the area, thereby reducing greenhouse gases. Permeability is calculated to be ~20-30 millidarcys for km-scale fault-focused fluid flow, using changes in natural gas seepage rates from well production, and poroelastic changes in formation pore-water pressure. In the Los Angeles (LA) basin, our characterization of formation water chemistry, including stable isotopic studies, allows the distinction between deep and shallow formations waters. Our multiphase computational-based modeling of petroleum migration demonstrates the important role of major faults on geological-scale fluid migration in the LA basin, and show how petroleum was dammed up against the Newport-Inglewood fault zone in a “geologically fast” interval of time (less than 0.5 million years). Furthermore, these fluid studies also will allow evaluation of potential cross-formational mixing of formation fluids. Lastly, our new study of helium isotopes in the LA basin shows a significant leakage of mantle helium along the Newport Inglewood fault zone (NIFZ), at flow rates up to 2 cm/yr. Crustal-scale fault permeability (~60 microdarcys) and advective versus conductive heat transport rates have been estimated using the observed helium isotopic data. The NIFZ is an important deep-seated fault that may crosscut a proposed basin decollement fault in this heavily populated area, and appears to allow seepage of helium from the mantle sources about 30 km beneath Los Angeles. The helium study has been widely cited in recent weeks by the news media, both in radio and on numerous web sites.

  6. Rotational differencies between the northern and southern Tyrrhenian domains: paleomagnetic constraints from the Amantea basin (Calabria, Italy)

    OpenAIRE

    Speranza, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Mattei, M.; Dipartimento di Scienze Geologiche, Universita` di Roma TRE, Rome; Sagnotti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Grasso, F.; Dipartimento di Scienze Geologiche, Università di Roma Tre, Largo S. Leonardo Murialdo 1, 00143 Roma, Italy

    2000-01-01

    We report on a palaeomagnetic study of upper Miocene sediments from the Amantea basin, located on the Tyrrhenian coast of Calabria. The magnetic mineralogy is dominated by greigite and subordinate magnetite in the Tortonian-Messinian clays (ten sites), and by hemoilmenite and magnetite in the underlaying sands and volcanic ashes (three sites), which have not been dated. Data from the Tortonian, Messinian clays pass both a reversal and a fold test, and define a 19° ± 11° clockwise rotation (wi...

  7. El-Niño southern oscillation and rainfall erosivity in the headwater region of the Grande River Basin, Southeast Brazil

    Directory of Open Access Journals (Sweden)

    C. R. Mello

    2011-12-01

    Full Text Available Relationships between regional climate and oceanic and atmospheric anomalies are important tools in order to promote the development of models for predicting rainfall erosivity, especially in regions with substantial intra-annual variability in the rainfall regime. In this context, this work aimed to analyze the rainfall erosivity in headwaters of Grande River Basin, Southern Minas Gerais State, Brazil. This study considered the two most representative environments, the Mantiqueira Range (MR and Plateau of Southern Minas Gerais (PSM. These areas are affected by the El Nino Southern Oscillation (ENSO indicators Sea Surface Temperature (SST for Niño 3.4 Region and Multivariate ENSO Index (MEI. Rainfall erosivity was calculated for individual rainfall events from January 2006 to December 2010. The analyses were conducted using the monthly data of ENSO indicators and the following rainfall variables: rainfall erosivity (EI30, rainfall depth (P, erosive rainfall depth (E, number of rainfall events (NRE, number of erosive rainfall events (NEE, frequency of occurrence of an early rainfall pattern (EP, occurrence of late rainfall pattern (LP and occurrence of intermediate rainfall patter (IP. Pearson's coefficient of correlation was used to evaluate the relationships between the rainfall variables and SST and MEI. The coefficients of correlation were significant for SST in the PSM sub-region. Correlations between the rainfall variables and negative oscillations of SST were also significant, especially in the MR sub-region, however, the Person's coefficients were lesser than those obtained for the SST positive oscillations. The correlations between the rainfall variables and MEI were also significant but lesser than the SST correlations. These results demonstrate that SST positive oscillations play a more important role in rainfall erosivity, meaning they were more influenced by El-Niño episodes. Also, these results have shown

  8. Elevation-Dependent Vegetation Greening of the Yarlung Zangbo River Basin in the Southern Tibetan Plateau, 1999–2013

    Directory of Open Access Journals (Sweden)

    Haidong Li

    2015-12-01

    Full Text Available The Yarlung Zangbo River basin is an important alley to transport moisture from the Indian Ocean to the inner Tibetan Plateau. With a wide range of elevations from 147 m to over 7000 m above sea level (a.s.l., ecosystems respond differently to climate change at various elevations. However, the pattern of elevation-dependent vegetation change and how it responds to recent warming have been rarely reported. Here, we investigated the pattern of vegetation greening at different elevations in this river basin using SPOT normalized difference vegetation index (NDVI data during 1999–2013, and examined its relationship with elevation-dependent changes in temperature and precipitation. The annual NDVI has increased by 8.83% from 1999 to 2013. In particular, the NDVI increased more apparently at lower elevations, but remained relatively stable or even decreased at high elevations. It seems that rising temperature has driven the basin-wide vegetation greening, but the greening rate is in contrast to the pattern of elevation-dependent warming (EDW with more significant temperature increase at higher elevations. It appears that decreasing precipitation does not reverse the overall increasing trend in NDVI, but relatively limited precipitation (<500 mm may constrain the NDVI increases, causing apparently stable or even decreased NDVI at higher elevations (>4000 m.

  9. Distribution and transportation of mercury from glacier to lake in the Qiangyong Glacier Basin, southern Tibetan Plateau, China.

    Science.gov (United States)

    Sun, Shiwei; Kang, Shichang; Huang, Jie; Li, Chengding; Guo, Junming; Zhang, Qianggong; Sun, Xuejun; Tripathee, Lekhendra

    2016-06-01

    The Tibetan Plateau is home to the largest aggregate of glaciers outside the Polar Regions and is a source of fresh water to 1.4 billion people. Yet little is known about the transportation and cycling of Hg in high-elevation glacier basins on Tibetan Plateau. In this study, surface snow, glacier melting stream water and lake water samples were collected from the Qiangyong Glacier Basin. The spatiotemporal distribution and transportation of Hg from glacier to lake were investigated. Significant diurnal variations of dissolved Hg (DHg) concentrations were observed in the river water, with low concentrations in the morning (8:00am-14:00pm) and high concentrations in the afternoon (16:00pm-20:00pm). The DHg concentrations were exponentially correlated with runoff, which indicated that runoff was the dominant factor affecting DHg concentrations in the river water. Moreover, significant decreases of Hg were observed during transportation from glacier to lake. DHg adsorption onto particulates followed by the sedimentation of particulate-bound Hg (PHg) could be possible as an important Hg removal mechanism during the transportation process. Significant decreases in Hg concentrations were observed downstream of Xiao Qiangyong Lake, which indicated that the high-elevation lake system could significantly affect the distribution and transportation of Hg in the Qiangyong Glacier Basin. PMID:27266318

  10. Three-dimensional mathematical model to simulate groundwater flow in the lower Palar River basin, southern India

    Science.gov (United States)

    Senthilkumar, M.; Elango, L.

    A three-dimensional mathematical model to simulate regional groundwater flow was used in the lower Palar River basin, in southern India. The study area is characterised by heavy ion of groundwater for agricultural, industrial and drinking water supplies. There are three major pumping stations on the riverbed apart from a number of wells distributed over the area. The model simulates groundwater flow over an area of about 392 km2 with 70 rows, 40 columns, and two layers. The model simulated a transient-state condition for the period 1991-2001. The model was calibrated for steady- and transient-state conditions. There was a reasonable match between the computed and observed heads. The transient model was run until the year 2010 to forecast groundwater flow under various scenarios of overpumping and less recharge. Based on the modelling results, it is shown that the aquifer system is stable at the present rate of pumping, excepting for a few locations along the coast where the groundwater head drops from 0.4 to 1.81 m below sea level during the dry seasons. Further, there was a decline in the groundwater head by 0.9 to 2.4 m below sea level in the eastern part of the area when the aquifer system was subjected to an additional groundwater withdrawal of 2 million gallons per day (MGD) at a major pumping station. Les modèles mathématiques en trois dimensions de l'écoulement souterrain régional sont très utiles pour la gestion des ressources en eau souterraine, car ils permettent une évaluation des composantes des processus hydrologiques et fournissent une description physique de l'écoulement de l'eau dans un aquifère. Une telle modélisation a été entreprise sur une partie du bassin inférieur de la rivière Palar, dans le sud de l'Inde. La zone d'étude est caractérisée par des prélèvements importants d'eau souterraine pour l'agriculture, l'industrie et l'eau potable. Il existe trois grandes stations de pompage sur la rivière en plus d'un certain nombre

  11. A new bush anole (Iguanidae, Polychrotinae, Polychrus) from the upper Marañon basin, Peru, with a redescription of Polychrus peruvianus (Noble, 1924) and additional information on Polychrus gutturosus Berthold, 1845.

    Science.gov (United States)

    Koch, Claudia; Venegas, Pablo J; Garcia-Bravo, Antonio; Böhme, Wolfgang

    2011-01-01

    We herein describe a new colorful species of Polychrus with a conspicuous sexual dimorphism from the dry forest of the northern portion of Región de La Libertad, Peru. The new species differs from all other Polychrus species, in that this species has very small dorsal scales and thus a higher number of scales around midbody and in the middorsal line from behind the occipital scales to the level of the posterior edge of the thigh. Furthermore, we redescribe Polychrus peruvianus whose original description is short and lacks information on intraspecific variation and sexual dimorphism. Also, we add some information on intraspecific variation and ecology of Polychrus gutturosus. Finally, we synonymize Polychrus spurrelli Boulenger with Polychrus gutturosus.

  12. Persistent toxic substances in soils and waters along an altitudinal gradient in the Laja River Basin, Central Southern Chile.

    Science.gov (United States)

    Barra, Ricardo; Popp, Peter; Quiroz, Roberto; Bauer, Coretta; Cid, Hernan; von Tümpling, Wolf

    2005-02-01

    In this study the levels and distribution of some persistent toxic substances (PTS) were investigated in soils, superficial water, and snow along an altitudinal gradient in the Laja River Basin (South Central Chile). The principal objective was to establish the basin's contamination status. The working hypothesis was that PTS levels and distribution in the basin are dependent on the degree of anthropogenic intervention. Fifteen PAHs, seven PCBs congeners, and three organochlorine pesticides were studied in superficial soil and water samples obtained along the altitudinal gradient and from a coastal reference station (Lleu-Lleu River). Soil samples were extracted using accelerated solvent extraction with acetone/cyclohexane (1:1) for PAHs and organochlorine compounds. Contaminants were extracted from water and snow samples by liquid-liquid extraction (LLE). PAH and organochlorine compound quantification was carried out by HPLC with fluorescence detection and GC-MS, respectively. PCBs in soils presented four different profiles in the altitudinal gradient, mainly determined by their chlorination degree; these profiles were not observed for the chlorinated pesticides. In general, the detected levels for the analyzed compounds were low for soils when compared with soil data from other remote areas of the world. Higher summation operator PAHs levels in soils were found in the station located at 227 masl (4243 ng g-1 TOC), in a forestry area and near a timber industry, where detected levels were up to eight times higher than the other sampling sites. In general, PAH levels and distribution seems to be dependent on local conditions. No pesticides were detected in surface waters. However, congeners of PCBs were detected in almost all sampling stations with the highest levels being found in Laja Lake waters, where 1.1 ng/l were observed. This concentration is two times higher than values reported for polluted lakes in the Northern Hemisphere. The presence of organochlorine

  13. Impact of riparian land-use patterns on Ephemeroptera community structure in river basins of the southern Western Ghats, India

    OpenAIRE

    Selvakumar C; Sivaramakrishnan K.G.; Janarthanan S.; Arumugam M; Arunachalam M.

    2014-01-01

    This study analysed the impact of riparian land use in structuring the larval ephemeropteran communities from 25 sites in streams and rivers of Kalakad-Mundanthurai Tiger Reserve (KMTR) of the southern end of the Western Ghats, India. A total of twenty-eight species belonging to twenty-four genera of six families were collected across all the sites. Baetidae and Leptophlebiidae were the most numerous and ubiquitous families, com...

  14. Aqueducts and geoglyphs : the response of Ancient Nasca to water shortages in the desert of Atacama (Peru)

    Science.gov (United States)

    Masini, Nicola; Lasaponara, Rosa

    2016-04-01

    The desert of Atacama is a plateau in South America, covering a 1,000-kilometre strip of land on the Pacific coast, west of the Andes mountains, between Chile and Peru. Due to the confluence of a cold ocean current (the Humboldt Current) along with other climatic factors, connected to the particular topography and geomorphology of the region, Atacama desert is one of the most arid areas of the world. In particular, in Nasca region (Southern Peru) the lack of water was (and still is) due to the following causes: (i) the scarce pluvial precipitations and the (ii) high infiltration capacity, and the consequent yearly significant reduction of the surface water (Schreiber & Lancho Rojas 2009). Over the millennia long periods of drought occurred and frequently the lack of water was persistent for several decades. Despite the arid and extreme nature of the environment, this region was populated by important civilizations, such as Paracas and Nasca, which flourished in the Early Intermediate period (200 BCE-500 AD) (Silvermann & Proulx 2002). In particular the Nasca civilization is well-known for its refined and colourful pottery, characterized by a rich icononographic repertory, and, above all, by the huge and mysterious geoglyphs drawn on the arid plateaus of the Rio Grande de Nasca Basin. In order to practice agriculture, the Nasca developed adequate strategies to cope with hostile environmental factors and water scarcity, building a very efficient aqueduct system. They were aided by the fact that underground water was likely enough close to the surface and accessible by constructing wells and underground aqueducts, known with quechua name of puquios (Schreiber & Lancho Rojas 2009; Lasaponara & Masini 2012a; 2012b) The effectiveness of the techniques of hydraulic engineering depended on the climate and the weather events that sometimes underwent drastic changes, as results of the cyclical phenomenon of El Niño Southern Oscillation (commonly called ENSO). Hence the

  15. Pottery from Peru. A Handbook. Second Edition.

    Science.gov (United States)

    Rammage, Alix

    One of three handbooks dealing with pottery traditions from around the world, this packet draws together information about historical, ethnographic, and pottery traditions of Peru. The first of 13 brief subsections focuses on Peru's land and people. A presentation of a potter's history of Peru is followed by a discussion of the Chavin Cult (800…

  16. Species composition and phytosociology of xerophytic plant communities after extreme rainfall in South Peru

    NARCIS (Netherlands)

    Montesinos, D.B.; Sykora, K.V.; Quipuscoa-Silvestre, Victor; Cleef, A.M.

    2015-01-01

    Abstract: We present a phytosociological overview of the arid and semi-arid montane vegetation of the province
    of Arequipa in southern Peru. The xerophytic vegetation was studied after extreme rainfall had promoted
    exceptionally lush vegetation and a high aboveground floristic diversity. We

  17. Carbon Isotopic tests on the Origins of the Shuram Anomaly from the San Juan Fm., Peru

    Science.gov (United States)

    Hodgin, E. B.

    2015-12-01

    Carbon isotope anomalies are associated with perturbations to the carbon cycle that offer insight into the geochemical evolution of the Earth. The largest Carbon isotope anomaly in earth history is the Shuram, which remains poorly understood in spite of being linked to the oxygenation of earth, the rise of metazoans, and a complete reorganization of the carbon cycle. From a basin transect of the carbonate-dominated San Juan Formation in southern Peru, we present evidence for the first clear example of the Shuram isotope anomaly in South America. Unique to this succession are ~140 meters of organic-rich black shale within the anomaly, containing as much as 4% TOC. Preliminary data from the organic-rich black shales of the San Juan Fm. confirm that δ13Corg is relatively invariant and does not covary with δ13Ccarb. These observations are consistent with other Shuram sections and support various models: an exogenous carbon source, an enlarged dissolved organic carbon pool, as well as authigenic carbonate production in organic-rich anoxic sediments. Critical tests of these models have been complicated by a paucity of organics in Shuram facies worldwide. Further analyses of the robust organics from the Shuram facies of the San Juan Fm. therefore hold promise in shedding light on the origin of the Shuram isotope anomaly and critical earth history events to which it has been linked.

  18. Sedimentology, rhythmicity and basin-fill architecture of a carbonate ramp depositional system with intermittent terrigenous influx: The Albian Kharfot Formation of the Jeza-Qamar Basin, Dhofar, Southern Oman

    Science.gov (United States)

    Salad Hersi, O.; Abbasi, I. A.; Al-Harthy, A.

    2016-01-01

    which received fine-grained siliciclastic influx from the land (westward). In southern Oman where Kharfot Formation accumulated, the platform was unrimmed ramp type basin with high fine clastic influx along with elevated carbonate production.

  19. Ecologic studies of Venezuelan encephalitis virus in Peru during 1970-1971.

    Science.gov (United States)

    Scherer, W F; Madalengoitia, J; Flores, W; Acosta, M

    1975-04-01

    Venezuelan encephalitis (VE) virus has intermittently produced epidemics and equine epizootics on the dry Pacific coastal plain of Peru since at least the 1930's. However, evidence that the virus exists in the Amazon region of Peru to the east of the Andes mountains was not obtained until antibodies were found in human sera collected in 1965, and 10 strains of the virus were isolated in a forest near the city of Iquitos, Peru during February and March 1971. Eight strains came from mosquitoes and two from dead sentinel hamsters. Three hamsters exposed in forests near Iquitos developed VE virus antibodies suggesting that hamster-benign strains also exist there. Antibody tests of equine sera revealed no evidence that VE virus was actively cycling during the late 1950's or 1960's in southern coastal Peru, where equine epizootics had occurred in the 1930's and 1940's. In northern coastal Peru bordering Ecuador, antibodies were present in equine sera, presumably residual from the 1969 outbreak caused by subtype I virus, since neutralizing antibody titers were higher to subtype I virus than to subtypes III or IV. No VE virus was detected in this northern region during the dry season of 1970 by use of sentinel hamsters. The possibility is considered that VE epidemics and equine epizootics on the Pacific coast of Peru are caused by movements of virus in infected vertebrates traversing Andean passes or in infected vertebrates or mosquitoes carried in airplanes from the Amazon region. PMID:235838

  20. A transect across Australia's southern margin in the Otway Basin region: crustal architecture and the nature of rifting from wide-angle seismic profiling

    Science.gov (United States)

    Finlayson, D. M.; Collins, C. D. N.; Lukaszyk, I.; Chudyk, E. C.

    1998-03-01

    The Otway Basin in southeastern Australia formed on a triangular-shaped area of extended continental lithosphere during two extensional episodes in Cretaceous-to-Miocene times which ultimately led to the separation of Australia and Antarctica. The velocity structure and crustal architecture of the Otway continental margin has been interpreted from offshore-onshore wide-angle seismic profiling data along a transect extending from near the northern Otway Basin margin with Palaeozoic outcrop to the deep ocean basin under the Southern Ocean. Along this transect, the Otway Continental Margin (OCM) Transect, the onshore half-graben geometry of Early Cretaceous deposition gives way to a 5-km-thick basin sequence (P-wave velocity 2.2-4.6 km/s) extending down the continental slope offshore to at least 60 km from the shoreline. At 120 km from the nearest shore, sonobuoy data indicate a 4-5 km sedimentary sequence overlying 7 km of crustal basement rocks above the Moho at 15 km depth (water depth 4220 m). Conspicuous strong Moho reflections are evident under the continental slope at about 10.2 s TWT. Basement is interpreted to be attenuated/faulted Palaeozoic rocks of the Delamerian and Lachlan Orogens (intruded with Jurassic volcanics) that thin from 16 km onshore to about 3.5 km at 120 km from the nearest shore. These rocks comprise a 3 km section that has a velocity of 5.5-5.7 km/s overlying deeper basement with a velocity of 6.15-6.35 km/s. Over the same distance the Moho shallows from a depth of 30 km onshore to 15 km depth at 120 km from the nearest shore, and then to about 12 km in the deep ocean at the limits of the profile (water depth 5200 m). The continent-ocean boundary (COB) is interpreted to be at a prominent topographic inflection point at the bottom of the continental slope in 4800 m of water. P-wave velocities in the lower crust are 6.4-6.8 km/s above a transition to the Moho, with an upper mantle velocity of 8.05 km/s. There is no evidence of massive high

  1. A new Xenacanthiformes shark (Chondrichthyes, Elasmobranchii from the Late Paleozoic Rio do Rasto Formation (Paraná Basin, Southern Brazil

    Directory of Open Access Journals (Sweden)

    VICTOR E. PAULIV

    2014-03-01

    Full Text Available The Brazilian records on Xenacanthiformes include teeth and cephalic spines from the Parnaíba, Amazonas and Paraná basins. This work describes a new species of Xenacanthidae, collected in an outcrop of Serrinha Member of Rio do Rasto Formation (Wordian to Wuchiapingian, Paraná Basin, municipality of Jacarezinho, State of Paraná. The teeth of the new species are two or three-cuspidated and the aboral surface show a smooth concavity and one rounded basal tubercle. The coronal surface presents one semi-spherical and subcircular coronal button, and also two lateral main cusps and one central (when present with less than one fifth of the size of the lateral cusps in the labial portion. The lateral cusps are asymmetric or symmetric, rounded in transversal section, lanceolate in longitudinal section, devoid of lateral carinae and lateral serrations, and with few smooth cristae of enameloid. In optical microscope the teeth show a trabecular dentine (osteodentine base, while the cusps are composed by orthodentine, and the pulp cavities are non-obliterated by trabecular dentine. The fossil assemblage in the same stratigraphical level and in the whole Rio do Rasto Formation indicates another freshwater record for xenacanthid sharks.

  2. A new Xenacanthiformes shark (Chondrichthyes, Elasmobranchii) from the Late Paleozoic Rio do Rasto Formation (Paraná Basin), Southern Brazil.

    Science.gov (United States)

    Pauliv, Victor E; Dias, Eliseu V; Sedor, Fernando A; Ribeiro, Ana Maria

    2014-03-01

    The Brazilian records on Xenacanthiformes include teeth and cephalic spines from the Parnaíba, Amazonas and Paraná basins. This work describes a new species of Xenacanthidae, collected in an outcrop of Serrinha Member of Rio do Rasto Formation (Wordian to Wuchiapingian), Paraná Basin, municipality of Jacarezinho, State of Paraná. The teeth of the new species are two or three-cuspidated and the aboral surface show a smooth concavity and one rounded basal tubercle. The coronal surface presents one semi-spherical and subcircular coronal button, and also two lateral main cusps and one central (when present) with less than one fifth of the size of the lateral cusps in the labial portion. The lateral cusps are asymmetric or symmetric, rounded in transversal section, lanceolate in longitudinal section, devoid of lateral carinae and lateral serrations, and with few smooth cristae of enameloid. In optical microscope the teeth show a trabecular dentine (osteodentine) base, while the cusps are composed by orthodentine, and the pulp cavities are non-obliterated by trabecular dentine. The fossil assemblage in the same stratigraphical level and in the whole Rio do Rasto Formation indicates another freshwater record for xenacanthid sharks.

  3. Status and understanding of groundwater quality in the two southern San Joaquin Valley study units, 2005-2006 - California GAMA Priority Basin Project

    Science.gov (United States)

    Burton, Carmen A.; Shelton, Jennifer L.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the southern San Joaquin Valley was investigated from October 2005 through March 2006 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project is conducted by the U.S. Geological Survey (USGS) in collaboration with the California State Water Resources Control Board and the Lawrence Livermore National Laboratory. There are two study units located in the southern San Joaquin Valley: the Southeast San Joaquin Valley (SESJ) study unit and the Kern County Subbasin (KERN) study unit. The GAMA Priority Basin Project in the SESJ and KERN study units was designed to provide a statistically unbiased, spatially distributed assessment of untreated groundwater quality within the primary aquifers. The status assessment is based on water-quality and ancillary data collected in 2005 and 2006 by the USGS from 130 wells on a spatially distributed grid, and water-quality data from the California Department of Public Health (CDPH) database. Data was collected from an additional 19 wells for the understanding assessment. The aquifer systems (hereinafter referred to as primary aquifers) were defined as that part of the aquifer corresponding to the perforation interval of wells listed in the CDPH database for the SESJ and KERN study units. The status assessment of groundwater quality used data from samples analyzed for anthropogenic constituents such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring inorganic constituents such as major ions and trace elements. The status assessment is intended to characterize the quality of untreated groundwater resources within the primary aquifers in the SESJ and KERN study units, not the quality of drinking water delivered to consumers. Although the status assessment applies to untreated groundwater, Federal and California regulatory and non-regulatory water-quality benchmarks that apply to drinking water are used

  4. New Middle Permian palaeopteran insects from Lodève Basin in southern France (Ephemeroptera, Diaphanopterodea, Megasecoptera

    Directory of Open Access Journals (Sweden)

    Jakub Prokop

    2011-09-01

    Full Text Available Three new palaeopteran insects are described from the Middle Permian (Guadalupian of Salagou Formation in the Lodève Basin (South of France, viz. the diaphanopterodean Alexrasnitsyniidae fam. n., based on Alexrasnitsynia permiana gen. et sp. n., the Parelmoidae Permelmoa magnifica gen. et sp. n., and Lodevohymen lapeyriei gen. et sp. n. (in Megasecoptera or Diaphanopterodea, family undetermined. In addition the first record of mayflies attributed to family Syntonopteridae (Ephemeroptera is reported. These new fossils clearly demonstrate that the present knowledge of the Permian insects remains very incomplete. They also confirm that the Lodève entomofauna was highly diverse providing links to other Permian localities and also rather unique, with several families still not recorded in other contemporaneous outcrops.

  5. Patterns of deep-water coral diversity in the Caribbean Basin and adjacent southern waters: an approach based on records from the R/V Pillsbury expeditions.

    Directory of Open Access Journals (Sweden)

    Iván Hernández-Ávila

    Full Text Available The diversity of deep-water corals in the Caribbean Sea was studied using records from oceanographic expeditions performed by the R/V Pillsbury. Sampled stations were sorted according to broad depth ranges and ecoregions and were analyzed in terms of species accumulation curves, variance in the species composition and contributions to alpha, beta and gamma diversity. According to the analysis of species accumulation curves using the Chao2 estimator, more diversity occurs on the continental slope (200-2000 m depth than on the upper continental shelf (60-200 m depth. In addition to the effect of depth sampling, differences in species composition related to depth ranges were detected. However, the differences between ecoregions are dependent on depth ranges, there were fewer differences among ecoregions on the continental slope than on the upper continental shelf. Indicator species for distinctness of ecoregions were, in general, Alcyonaria and Antipatharia for the upper continental shelf, but also the scleractinians Madracis myriabilis and Cladocora debilis. In the continental slope, the alcyonarian Placogorgia and the scleractinians Stephanocyathus and Fungiacyathus were important for the distinction of ecoregions. Beta diversity was the most important component of gamma diversity in the Caribbean Basin. The contribution of ecoregions to alpha, beta and gamma diversity differed with depth range. On the upper continental shelf, the Southern Caribbean ecoregion contributed substantially to all components of diversity. In contrast, the northern ecoregions contributed substantially to the diversity of the Continental Slope. Strategies for the conservation of deep-water coral diversity in the Caribbean Basin must consider the variation between ecoregions and depth ranges.

  6. Inconsistent magnetic polarities in magnetite- and greigite-bearing sediments: Understanding complex magnetizations in the late Messinian in the Adana Basin (southern Turkey)

    Science.gov (United States)

    Lucifora, Stella; Cifelli, Francesca; Mattei, Massimo; Sagnotti, Leonardo; Cosentino, Domenico; Roberts, Andrew P.

    2012-10-01

    We present paleomagnetic, rock magnetic and scanning electron microscope data from three upper Messinian stratigraphic sections from the Adana Basin (southern Turkey). The collected samples are from fine-grained units, which were deposited during the Messinian Salinity Crisis (within subchron C3r). Paleomagnetic results reveal an inconsistent polarity record, related to a mixture of magnetite and greigite that hinders determination of a reliable magnetostratigraphy. Three classes of samples are recognized on the basis of paleomagnetic results. The first is characterized by a single magnetization component, with normal polarity, that is stable up to 530-580°C and is carried by magnetite. The second is characterized by a single magnetization component, with reversed polarity, that is stable up to 330-420°C. This magnetization is due to greigite, which developed after formation of slumps and before tectonic tilting of the studied successions. The third is characterized by reversed polarity, which is stable up to 530-580°C. We interpret this component as a primary magnetization carried by fine-grained and magnetically stable detrital magnetite. Results indicate that in the Adana Basin the assumption that a primary magnetization is carried by magnetite, and a magnetic overprint carried by greigite, does not hold because a late magnetic overprint has also been found for magnetite-bearing samples. Our data illustrate the complexity of magnetostratigraphic reconstructions in successions characterized by variable mixtures of magnetic minerals with different magnetic stability that formed at different stages. We demonstrate the need to perform detailed magnetic mineralogy analyses when conducting magnetostratigraphic studies of clay-rich sediments from marine or lacustrine environments.

  7. Sone megafan: A non-Himalayan megafan of craton origin on the southern margin of the middle Ganga Basin, India

    Science.gov (United States)

    Sahu, Sudarsan; Saha, Dipankar; Dayal, Shankar

    2015-12-01

    Researchers in the last few decades have focused on the fluvial megafans at the base of Himalayan foothills in the Ganga Basin. No major effort has so far been made to delineate any such large depositional environment at the base of the northern Indian peninsular craton at the distal parts of the basin. In this work, for the first time, we document a megafan, unusually created by the cratonic Sone River in the marginal plains south of the Ganga. The geomorphology of the megafan surface, distribution of palaeochannels, sedimentology, and areal extent of the megafan are described. The study also reconstructs the tectonic and palaeoclimatic conditions, which might have helped in sediment supply from the cratonic catchment areas of the Sone. We suggest tectonic control over the Sone River channel dynamics and development of the megafan. The oval- and fan-shaped, craton-derived sediment body covers an area of around 12,000 km2 in the marginal plains and about 9000 km2 in the central alluvium north of the Ganga River. The megafan is around 190 km long and ~ 240 km wide. The mean slope of the megafan surface is ~ 0.03°. An onlap of Himalayan sediments has occurred over the megafan at its toe parts caused by southward encroachment of the Ganga during the Holocene. The megafan sediments comprise brownish yellow fine to coarse sand and gravels with an admixture of carbonaceous nodules (kankars). The thickness of the megafan sediment, which directly overlies the Precambrian basement, varies from only a few meters in the south near the peninsular craton to ~ 1000 m at the north in the central alluvial plain. The granular zones form prolific aquifer systems in an otherwise poor hydrogeological setting of the marginal plains.

  8. The depositional setting of the Late Quaternary sedimentary fill in southern Bannu basin, Northwest Himalayan fold and thrust belt, Pakistan

    KAUST Repository

    Farid, Asam M.

    2014-07-10

    Geostatistical variogram and inversion techniques combined with modern visualization tools have made it possible to re-model one-dimensional electrical resistivity data into two-dimensional (2D) models of the near subsurface. The resultant models are capable of extending the original interpretation of the data to depict alluvium layers as individual lithological units within the 2D space. By tuning the variogram parameters used in this approach, it is then possible to visualize individual lithofacies and geomorphological features for these lithologic units. The study re-examines an electrical resistivity dataset collected as part of a groundwater study in an area of the Bannu basin in Pakistan. Additional lithological logs from boreholes throughout the area have been combined with the existing resistivity data for calibration. Tectonic activity during the Himalayan orogeny uplifted and generated significant faulting in the rocks resulting in the formation of a depression which subsequently has been filled with clay-silt and dirty sand facies typical of lacustrine and flood plain environments. Streams arising from adjacent mountains have reworked these facies which have been eroded and replaced by gravel-sand facies along channels. It is concluded that the sediments have been deposited as prograding fan shaped bodies, flood plain, and lacustrine deposits. Clay-silt facies mark the locations of paleo depressions or lake environments, which have changed position over time due to local tectonic activity and sedimentation. The Lakki plain alluvial system has thus formed as a result of local tectonic activity with fluvial erosion and deposition characterized by coarse sediments with high electrical resistivities near the mountain ranges and fine sediments with medium to low electrical resistivities towards the basin center. © 2014 Springer International Publishing Switzerland.

  9. Impact of riparian land-use patterns on Ephemeroptera community structure in river basins of the southern Western Ghats, India

    Directory of Open Access Journals (Sweden)

    Selvakumar C.

    2014-02-01

    Full Text Available This study analysed the impact of riparian land use in structuring the larval ephemeropteran communities from 25 sites in streams and rivers of Kalakad-Mundanthurai Tiger Reserve (KMTR of the southern end of the Western Ghats, India. A total of twenty-eight species belonging to twenty-four genera of six families were collected across all the sites. Baetidae and Leptophlebiidae were the most numerous and ubiquitous families, comprising eight genera in each family and eleven and nine species, respectively. The physico-chemical parameters and species richness and abundance of mayflies varied across streams and rivers with different riparian land-use types. Species distribution was influenced by the environmental gradients. Canonical Correspondence Analysis revealed a clear separation of the mayfly assemblages along water quality and riparian land-use gradients. The results of this study suggest that Ephemeroptera taxa can be potentially used as sensitive indicators of riparian land use in lotic ecosystems.

  10. Quantitative geomorphologic data of the reactivated variscan Hluboká fault system (Budĕjovice Basin, southern Bohemian Massif)

    Science.gov (United States)

    Popotnig, Angelika; Tschegg, Dana; Decker, Kurt

    2015-04-01

    The NW-SE and NNE-SSW striking Hluboká-Rudolfov-Fault System in southern Bohemia is a potentially active late Variscan fault. It was repeatedly activated in Mesozoic, Miocene and Pliocene times and forms a "disputed seismic source" in the vicinity of the nuclear power plant of Temelin. The Fault System at the NE and SE margin of the Budĕjovice Basin with its up to 340 m thick Cretaceous to Neogene sediments overlaying the hanging wall of the Fault System is partly characterized by a prominent linear morphological scarp. Geomorpholigic analysis mainly focus on mountain fronts at the basin margin crossing the Hluboká and Rudolfov fault as well as on the NE facing slope of the Racice Mountain which is not crossing the fault. Analyses use morphological parameters of small ephemeric tributaries of the Vltava River, which are all similar with respect to their catchments, hydrological conditions and location in crystalline basement rocks. Morphological differences in valley shapes are therefore likely to result from different amounts of uplift of the catchments with respect to the Vltava River. All parameters were measured from a 10 m resolution DEM and digital topographic maps 1:10,000. Additional field measurements were made at locations where the resolution of the digital data is insufficient. Data show extremely low mountain-front-sinuosity of the hillslope forming the footwall of the Hluboká Fault characterizing a very straight mountain front at the fault and an uplift influenced morphology. Almost all values differ significantly from those observed at the other mountain slopes. The results are in line with the evidence obtained from mountain sinuosity. The mountain slope at the faults show deep and narrow V-shaped valleys with streams that are actively incising probably responding to continuous uplift. Vf (Valley-Floor-Width-to-Height) and SL (Stream Length) values are generally lower than those from drainages not crossing the fault. Convex-up thalweg sections

  11. Peru. America = Las Americas [Series].

    Science.gov (United States)

    Toro, Leonor; Doran, Sandra

    Intended for elementary teachers to use with migrant students, this bilingual English/Spanish social studies resource booklet provides an encyclopedia-style overview of Peru's history, geography, economy, and culture. Topics included are the people, geographic regions, festivals and celebrations, the economy, natural resources, Lake Titicaca,…

  12. Holocene late Pleistocene non-tropical carbonate sediments and tectonic history of the western rift basin margin of the southern Gulf of California

    Science.gov (United States)

    Halfar, Jochen; Godinez-Orta, Lucio; Goodfriend, Glenn A.; Mucciarone, David A.; Ingle, James C.; Holden, Peter

    2001-10-01

    Using high-resolution seismic reflection profiling and dating of (1) shallow marine vibracores and (2) sediments collected from uplifted marine terraces we reconstruct the tectonic history and sediment accumulation patterns of Holocene to late Pleistocene warm-temperate to subtropical carbonates in the southern Gulf of California, Mexico. The study was conducted in the vicinity of La Paz where carbonates form along the fault bounded narrow western shelf of the tectonically active Gulf of California rift basin. The non-tropical nature of the setting is responsible for (1) poor cementation of the bioclastic carbonates, and (2) a composition which is dominated by rhodoliths (coralline red algae), corals and mollusks. Unrimmed carbonate flats forming in small pocket bays and a rhodolith bioherm, which has a surface area of more than 20 km 2 and is up to 16 m thick, constitute the major carbonate factories. Holocene carbonate accumulation rates were deduced from seismic and core data and are highest on the rhodolith bioherm (260 cm/ka) and in subtidal zones of pocket bays (210 cm/ka), and lowest on the inner and middle shelf (100 cm/ka). Taken together, rates of carbonate accumulation are intermediate in magnitude between higher rates recorded in fully tropical carbonate settings and lower rates typical of cool-water carbonates. Seismic reflection profiles demonstrate that Isla Espiritu Santo in the center of the study area is a west dipping fault block, which is tectonically influenced by two distinct faults, the La Paz and Espiritu Santo faults. The latter fault accommodates at least 700 m of east-side down normal offset, and forms a steep eastern escarpment leading into the La Paz slope basin. Some of the sediments produced in the shallow carbonate factories of the narrow La Paz shelf are transported across this escarpment and are redeposited in the slope basin at a water depth of 750 m. Uranium-series dates of marine terraces exposed on Isla Espiritu Santo indicate

  13. Natural gas distribution network of Lima and Callao, Peru

    Energy Technology Data Exchange (ETDEWEB)

    Maroye, Stephane; Aerssens, Andre [Tractebel Engineering, Lima (Peru)

    2005-07-01

    In May 2002, Suez-Tractebel was awarded by the government of Peru a 30-year concession for the construction and operation of the gas distribution network in Lima, Peru. On 10 July, 2004, first gas was delivered to Lima, 1 month ahead of the official date. This gas distribution network, operated by GNLC (Gas Natural de Lima y Callao), delivers gas to some of the largest industries and power generators in and around Lima and the harbour area of Callao. Gas delivered in Lima comes through a 700 km HP gas pipeline from Camisea fields. This pipeline is operated by TGP (Transportadora de Gas del Peru). A City Gate is located at Lurin, on the southern side of the city. The gas distribution network is made of a 62 km main pipeline (20') with 25 km laterals. The main pipeline is operated at 50 bar, as the main customer, the Etevensa power plant, is located on the northern side of the city. Due to this high operating pressure combined to the surroundings, specific design philosophies were adopted to meet the extreme safety requirements. This paper highlights the specific measures taken during construction phase and the experience of the first months of operation of this challenging project. (author)

  14. Distribution of Aboveground Live Biomass in the Amazon Basin

    Science.gov (United States)

    Saatchi, S. S.; Houghton, R. A.; DosSantos Alvala, R. C.; Soares, J. V.; Yu, Y.

    2007-01-01

    The amount and spatial distribution of forest biomass in the Amazon basin is a major source of uncertainty in estimating the flux of carbon released from land-cover and land-use change. Direct measurements of aboveground live biomass (AGLB) are limited to small areas of forest inventory plots and site-specific allometric equations that cannot be readily generalized for the entire basin. Furthermore, there is no spaceborne remote sensing instrument that can measure tropical forest biomass directly. To determine the spatial distribution of forest biomass of the Amazon basin, we report a method based on remote sensing metrics representing various forest structural parameters and environmental variables, and more than 500 plot measurements of forest biomass distributed over the basin. A decision tree approach was used to develop the spatial distribution of AGLB for seven distinct biomass classes of lowland old-growth forests with more than 80% accuracy. AGLB for other vegetation types, such as the woody and herbaceous savanna and secondary forests, was directly estimated with a regression based on satellite data. Results show that AGLB is highest in Central Amazonia and in regions to the east and north, including the Guyanas. Biomass is generally above 300Mgha(sup 1) here except in areas of intense logging or open floodplains. In Western Amazonia, from the lowlands of Peru, Ecuador, and Colombia to the Andean mountains, biomass ranges from 150 to 300Mgha(sup 1). Most transitional and seasonal forests at the southern and northwestern edges of the basin have biomass ranging from 100 to 200Mgha(sup 1). The AGLB distribution has a significant correlation with the length of the dry season. We estimate that the total carbon in forest biomass of the Amazon basin, including the dead and below ground biomass, is 86 PgC with +/- 20% uncertainty.

  15. Petrography and geochemistry of Oligocene bituminous coal from the Jiu Valley, Petrosani basin (southern Carpathian Mountains), Romania

    Energy Technology Data Exchange (ETDEWEB)

    Belkin, Harvey E.; Tewalt, Susan J. [U.S. Geological Survey, 956 National Center, Reston, VA 20192 (United States); Hower, James C. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); Stucker, J.D. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); University of Kentucky Department of Earth and Environmental Sciences, Lexington, KY 40506 (United States); O' Keefe, Jennifer M.K. [Morehead State University, Morehead, KY, 40351 (United States); Tatu, Calin A. [University of Medicine and Pharmacy, Department of Immunology, Clinical Laboratory No. 1, Pta. E. Murgu No. 2, RO-1900 Timisoara (Romania); Buia, Grigore [University of Petrosani, Department of Geology, University St. 20, RO-2675 Petrosani (Romania)

    2010-05-01

    Belt samples of Oligocene (Chattian) bituminous coal from 10 underground mines located in the Jiu Valley, Hunedoara County, Petrosani basin, Romania, have been examined and analyzed for proximate and ultimate analysis, major-, minor- and trace-element chemistry, organic petrography, and vitrinite reflectance. The mineral chemistry and mode of occurrence of trace elements also have been investigated using SEM and electron microprobe techniques. Twenty coal beds occur in the Jiu Valley and most of the samples are from bed no. 3, the most productive bed of the Dilja-Uricani Formation of Oligocene age. The Petrosani basin, oriented SW-NE, is 48-km long, 10-km wide at the eastern part and 2-km wide at the western part. The coal mines are distributed along the center of the valley generally following the Jiu de Vest River. Reflectance measurements indicate that the rank of the coals ranges from high-volatile B to high-volatile A bituminous. Overall, rank decreases from the southwest to the northeast. In bed no. 3, R{sub max} varies from 0.75% in the northeast to 0.93% in the southwest. Although, most Oligocene coals in Romania and adjacent countries are lignite in rank, the Jiu Valley bituminous coals have been affected by regional metamorphism and attending hydrothermal fluids related to the Alpine orogenic event. The coals are all dominated by vitrinite; resinite and funginite are important minor macerals in most of the coals. Pyrite and carbonate generally dominate the mineral assemblages with carbonate more abundant in the northwest. Siderite occurs as nodules and masses within the macerals (generally vitrinite). Dolomite and calcite occur as fracture fillings, plant-cell fillings, and in other authigenic forms. Late-stage fracture fillings are siderite, dolomite, calcite, and ankerite. In one instance, two populations of siderite ({proportional_to} 35 and {proportional_to} 45 wt.% FeO) plus ankerite fill a large fracture. Late-stage pyrite framboid alteration is Ni

  16. [Correlation Among Soil Organic Carbon, Soil Inorganic Carbon and the Environmental Factors in a Typical Oasis in the Southern Edge of the Tarim Basin].

    Science.gov (United States)

    Gong, Lu; Zhu, Mei-ling; Liu, Zeng-yuan; Zhang, Xue-ni; Xie, Li-na

    2016-04-15

    We analyzed the differentiation among the environmental factors and soil organic/inorganic carbon contents of irrigated desert soil, brown desert soil, saline soil and aeolian sandy soil by classical statistics methods, and studied the correlation between soil carbon contents and the environmental factor by redundancy analysis (RDA) in a typical oasis of Yutian in the southern edge of the Tarim Basin. The results showed that the average contents of soil organic carbon and soil inorganic carbon were 2.51 g · kg⁻¹ and 25.63 g · kg⁻¹ respectively. The soil organic carbon content of the irrigated desert soil was significantly higher than those of brown desert soil, saline soil and aeolian sandy soil, while the inorganic carbon content of aeolian sandy soil was significantly higher than those of other soil types. The soil moisture and nutrient content were the highest in the irrigated desert soil and the lowest in the aeolian sandy sail. All soil types had high degree of salinization except the irrigated desert soil. The RDA results showed that the impacts of environmental factors on soil carbon contents ranked in order of importance were total nitrogen > available phosphorus > soil moisture > ground water depth > available potassium > pH > total salt. The soil carbon contents correlated extremely significantly with total nitrogen, available phosphorus, soil moisture and ground water depth (P soil carbon contents and other environmental factors (P > 0.05). PMID:27548977

  17. Regional Tectonic Control of Tertiary Mineralization and Recent Faulting in the Southern Basin-Range Province, an Application of ERTS-1 Data

    Science.gov (United States)

    Bechtold, I. C.; Liggett, M. A.; Childs, J. F.

    1973-01-01

    Research based on ERTS-1 MSS imagery and field work in the southern Basin-Range Province of California, Nevada and Arizona has shown regional tectonic control of volcanism, plutonism, mineralization and faulting. This paper covers an area centered on the Colorado River between 34 15' N and 36 45' N. During the mid-Tertiary, the area was the site of plutonism and genetically related volcanism fed by fissure systems now exposed as dike swarms. Dikes, elongate plutons, and coeval normal faults trend generally northward and are believed to have resulted from east-west crustal extension. In the extensional province, gold silver mineralization is closely related to Tertiary igneous activity. Similarities in ore, structural setting, and rock types define a metallogenic district of high potential for exploration. The ERTS imagery also provides a basis for regional inventory of small faults which cut alluvium. This capability for efficient regional surveys of Recent faulting should be considered in land use planning, geologic hazards study, civil engineering and hydrology.

  18. Spatial data fusion and analysis for soil characterization: a case study in a coastal basin of south-western Sicily (southern Italy

    Directory of Open Access Journals (Sweden)

    Donato Sollitto

    2012-03-01

    Full Text Available Salinization is one of the most serious problems confronting sustainable agriculture in semi-arid and arid regions. Accurate mapping of soil salinization and the associated risk represent a fundamental step in planning agricultural and remediation activities. Geostatistical analysis is very useful for soil quality assessment because it makes it possible to determine the spatial relationships between selected variables and to produce synthetic maps of spatial variation. The main objective of this paper was to map the soil salinization risk in the Delia-Nivolelli alluvial basin (south-western Sicily, southern Italy, using multivariate geostatistical techniques and a set of topographical, physical and soil hydraulic properties. Elevation data were collected from existing topographic maps and analysed preliminarily to improve the estimate precision of sparsely sampled primary variables. For interpolation multi-collocated cokriging was applied to the dataset, including textural and hydraulic properties and electrical conductivity measurements carried out on 128 collected soil samples, using elevation data as auxiliary variable. Spatial dependence among elevation and physical soil properties was explored with factorial kriging analysis (FKA that could isolate and display the sources of variation acting at different spatial scales. FKA isolated significant regionalised factors which give a concise description of the complex soil physical variability at the different selected spatial scales. These factors mapped, allowed the delineation of zones at different salinisation risk to be managed separately to control and prevent salinization risk. The proposed methodology could be a valid support for land use and soil remediation planning at regional scale.

  19. Occurrence, thermal evolution and primary migration processes derived from studies of organic matter in the Lucaogou source rock at the southern margin of the Junggar Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Lucaogou Formation carbonate-rich oil shale source rock is exposed at the southern margin of the Junggar Basin, Xinjiang, NW China. We have sampled it in detail and conducted microstructural, mineralogical and geochemical studies, including thin section petrography, UV fluorescence petrography, X-ray diffraction, vitrinite reflectance, bitumen reflectance, fluid inclusion analysis and Raman spectroscopy. Organic matter is disseminated through the carbonate-bearing siltstone source rocks and concentrated in numerous bedding parallel stylolites and in two sets of carbonate veins, one along bedding parallel fractures and the other cross-cutting stylolites and bedding. The research about maturity of organic matter finds vitrinite reflectance values increase from the dispersed kerogen (0.64%) to the stylolites (the one of oriented vitrinite is 0.72% and the one of migrated bitumen is 2.38%); Homogenization temperatures of fluid inclusions in veins containing hydrocarbon fluid inclusions show an increase from 178.5℃ in the bedding parallel veins to 222℃ in the cross-cutting veins, confirmed by Raman spectroscopy. These results support a model of progressive heating accompanied by fluid loss during later stages of thermal maturation of source rock and the onset of primary migration. Obviously, the occurrence of organic matter is the trace of hydrocarbon primary migration, and the bedding lamination surfaces and cross-cutting fissures are the principal pathways of hydrocarbon-bearing fluids migration. Bedding lamination surfaces evolved into stylolites along the earliest primary migration pathways, followed by bedding parallel and cross-cutting fissures.

  20. Permeability prediction in deep coal seam: a case study on the No. 3 coal seam of the Southern Qinshui Basin in China.

    Science.gov (United States)

    Guo, Pinkun; Cheng, Yuanping

    2013-01-01

    The coal permeability is an important parameter in mine methane control and coal bed methane (CBM) exploitation, which determines the practicability of methane extraction. Permeability prediction in deep coal seam plays a significant role in evaluating the practicability of CBM exploitation. The coal permeability depends on the coal fractures controlled by strata stress, gas pressure, and strata temperature which change with depth. The effect of the strata stress, gas pressure, and strata temperature on the coal (the coal matrix and fracture) under triaxial stress and strain conditions was studied. Then we got the change of coal porosity with strata stress, gas pressure, and strata temperature and established a coal permeability model under tri-axial stress and strain conditions. The permeability of the No. 3 coal seam of the Southern Qinshui Basin in China was predicted, which is consistent with that tested in the field. The effect of the sorption swelling on porosity (permeability) firstly increases rapidly and then slowly with the increase of depth. However, the effect of thermal expansion and effective stress compression on porosity (permeability) increases linearly with the increase of depth. The most effective way to improve the permeability in exploiting CBM or extracting methane is to reduce the effective stress. PMID:24396293

  1. [Correlation Among Soil Organic Carbon, Soil Inorganic Carbon and the Environmental Factors in a Typical Oasis in the Southern Edge of the Tarim Basin].

    Science.gov (United States)

    Gong, Lu; Zhu, Mei-ling; Liu, Zeng-yuan; Zhang, Xue-ni; Xie, Li-na

    2016-04-15

    We analyzed the differentiation among the environmental factors and soil organic/inorganic carbon contents of irrigated desert soil, brown desert soil, saline soil and aeolian sandy soil by classical statistics methods, and studied the correlation between soil carbon contents and the environmental factor by redundancy analysis (RDA) in a typical oasis of Yutian in the southern edge of the Tarim Basin. The results showed that the average contents of soil organic carbon and soil inorganic carbon were 2.51 g · kg⁻¹ and 25.63 g · kg⁻¹ respectively. The soil organic carbon content of the irrigated desert soil was significantly higher than those of brown desert soil, saline soil and aeolian sandy soil, while the inorganic carbon content of aeolian sandy soil was significantly higher than those of other soil types. The soil moisture and nutrient content were the highest in the irrigated desert soil and the lowest in the aeolian sandy sail. All soil types had high degree of salinization except the irrigated desert soil. The RDA results showed that the impacts of environmental factors on soil carbon contents ranked in order of importance were total nitrogen > available phosphorus > soil moisture > ground water depth > available potassium > pH > total salt. The soil carbon contents correlated extremely significantly with total nitrogen, available phosphorus, soil moisture and ground water depth (P carbon contents and other environmental factors (P > 0.05).

  2. Impact of depositional facies on the distribution of diagenetic alterations in the Devonian shoreface sandstone reservoirs, Southern Ghadamis Basin, Libya

    Science.gov (United States)

    Khalifa, Muftah Ahmid; Morad, Sadoon

    2015-11-01

    The middle Devonian, shoreface quartz arenites (present-day burial depths 2833-2786 m) are important oil and gas reservoirs in the Ghadamis Basin, western Libya. This integrated petrographic and geochemical study aims to unravel the impact of depositional facies on distribution of diagenetic alterations and, consequently, related reservoir quality and heterogeneity of the sandstones. Eogenetic alterations include the formation of kaolinite, pseudomatrix, and pyrite. The mesogenetic alterations include cementation by quartz overgrowths, Fe-dolomite/ankerite, and illite, transformation of kaolinite to dickite, illitization of smectite, intergranular quartz dissolution, and stylolitization, and albitization of feldspar. The higher energy of deposition of the coarser-grained upper shoreface sandstones combined with less extensive chemical compaction and smaller amounts of quartz overgrowths account for their better primary reservoir quality compared to the finer-grained, middle-lower shoreface sandstones. The formation of kaolin in the upper and middle shoreface sandstones is attributed to a greater flux of meteoric water. More abundant quartz overgrowths in the middle and lower shoreface is attributed to a greater extent of stylolitization, which was promoted by more abundant illitic clays. This study demonstrated that linking the distribution of diagenetic alterations to depositional facies of shoreface sandstones leads to a better understanding of the impact of these alterations on the spatial and temporal variation in quality and heterogeneity of the reservoirs.

  3. Holocene dinoflagellate cyst record of climate and marine primary productivity change in the Santa Barbara Basin, southern California.

    Science.gov (United States)

    Pospelova, Vera; Mertens, Kenneth N.; Hendy, Ingrid, L.; Pedersen, Thomas F.

    2015-04-01

    High-resolution sedimentary records of dinoflagellate cysts and other marine palynomorphs from the Santa Barbara Basin (Ocean Drilling Program Hole 893A) demonstrate large variability of primary productivity during the Holocene, as the California Current System responded to climate change. Throughout the sequence, dinoflagellate cyst assemblages are characterized by the dominance of cysts produced by heterotrophic dinoflagellates, and particularly by Brigantedinium, accompanied by other upwelling-related taxa such as Echinidinium and cysts of Protoperidinium americanum. During the early Holocene (~12-7 ka), the species richness is relatively low (16 taxa) and genius Brigantedinium reaches the highest relative abundance, thus indicating nutrient-rich and highly productive waters. The middle Holocene (~7-3.5 ka) is characterized by relatively constant cyst concentrations, and dinoflagellate cyst assemblages are indicative of a slight decrease in sea-surface temperature. A noticeable increase and greater range of fluctuations in the cyst concentrations during the late Holocene (~3.5-1 ka) indicate enhanced marine primary productivity and increased climatic variability, most likely related to the intensification of El Niño-like conditions. Keywords: dinoflagellate cysts, Holocene, North Pacific, climate, primary productivity.

  4. Status and understanding of groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units, 2006-2007--California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units was investigated as part of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The three study units are located in the Sierra Nevada region of California in parts of Nevada, Placer, El Dorado, Madera, Tulare, and Kern Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board, in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The project was designed to provide statistically robust assessments of untreated groundwater quality within the primary aquifer systems used for drinking water. The primary aquifer systems (hereinafter, primary aquifers) for each study unit are defined by the depth of the screened or open intervals of the wells listed in the California Department of Public Health (CDPH) database of wells used for municipal and community drinking-water supply. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifers; shallower groundwater may be more vulnerable to contamination from the surface. The assessments for the Tahoe-Martis, Central Sierra, and Southern Sierra study units were based on water-quality and ancillary data collected by the USGS from 132 wells in the three study units during 2006 and 2007 and water-quality data reported in the CDPH database. Two types of assessments were made: (1) status, assessment of the current quality of the groundwater resource, and (2) understanding, identification of the natural and human factors affecting groundwater quality. The assessments characterize untreated groundwater quality, not the quality of treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentrations divided by benchmark concentrations) were used for evaluating groundwater quality for those

  5. A review on tectonic record of strain buildup and stress release across the Andean forearc along the Gulf of Guayaquil-Tumbes basin (GGTB) near Ecuador-Peru border

    OpenAIRE

    2013-01-01

    Gravimetric and geologic data show that the reactivation of the Neogene Interandean depression and/or the ~75 - 65 Ma ophiolite suture into the modern dynamic of the Andes controlled the Gulf of Guayaquil Tumbes basin (GGTB) location and evolution during the past 1.8 - 1.6 Myr at least. Depending on whether the remobilization occurred along the in- terandean depression or the ophiolite suture, the GGTB evolved trough pure or simple shear mechanisms, respectively. Because the GGTB exhibits an ...

  6. Paleomagnetic and geochronological study of Carboniferous forearc basin rocks in the Southern New England Orogen (Eastern Australia)

    Science.gov (United States)

    Pisarevsky, Sergei A.; Rosenbaum, Gideon; Shaanan, Uri; Hoy, Derek; Speranza, Fabio; Mochales, Tania

    2016-06-01

    We present results of a paleomagnetic study from Carboniferous forearc basin rocks that occur at both limbs of the Texas Orocline (New England Orogen, eastern Australia). Using thermal and alternating field demagnetizations, two remanence components have been isolated from rocks sampled from the Emu Creek terrane, in the eastern limb of the orocline. A middle-temperature Component M is post-folding and was likely acquired during low-temperature oxidation at 65-35 Ma. A high-temperature Component H is pre-folding, but its comparison with the paleomagnetic data from coeval rocks in the northern Tamworth terrane on the other limb of Texas Orocline does not indicate rotations around a vertical axis, as expected from geological data. A likely explanation for this apparent discrepancy is that Component H postdates the oroclinal bending, but predates folding in late stages of the 265-230 Ma Hunter Bowen Orogeny. The post-Kiaman age of Component H is supported by the presence of an alternating paleomagnetic polarity in the studied rocks. A paleomagnetic study of volcanic and volcaniclastic rocks in the Boomi Creek area (northern Tamworth terrane) revealed a stable high-temperature pre-folding characteristic remanence, which is dated to c. 318 Ma using U-Pb zircon geochronology. The new paleopole (37.8°S, 182.7°E, A95 = 16.2°) is consistent with previously published poles from coeval rocks from the northern Tamworth terrane. The combination of our new paleomagnetic and geochronological data with previously published results allows us to develop a revised kinematic model of the New England Orogen from 340 Ma to 270 Ma, which compared to the previous model, incorporates a different orientation of the northern Tamworth terrane at 340 Ma.

  7. Peru struggles to maintain crude production

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-14

    Revival of Peru's moribund oil and gas industry in the 1990s hinges on whether the new administration of President Alberto Fujimori is successful in attracting foreign investment in Peru. Fujimori's success would mean Peru pushing ahead into stepped up exploration and major development projects, such as the huge Camisea gas/condensate field discovered 2 years ago. His failure could mean Peru continuing to fall further behind in its already lagging low oil production. Huge sums of money will be needed. Peru also needs to succeed in its efforts to become creditworthy again for international agencies, foreign governments, and commercial banks. Meanwhile, Petroleos del Peru SA (Petroperu), the state oil company, will have to transfer an increasing share of its operations to private investors. But the company is likely to try to hold onto producing fields, even though it is unable to maintain full output.

  8. Depositional architecture of a mixed travertine-terrigenous system in a fault-controlled continental extensional basin (Messinian, Southern Tuscany, Central Italy)

    Science.gov (United States)

    Croci, Andrea; Della Porta, Giovanna; Capezzuoli, Enrico

    2016-03-01

    The extensional Neogene Albegna Basin (Southern Tuscany, Italy) includes several thermogene travertine units dating from the Miocene to Holocene time. During the late Miocene (Messinian), a continental fault-controlled basin (of nearly 500-km2 width) was filled by precipitated travertine and detrital terrigenous strata, characterized by a wedge-shaped geometry that thinned northward, with a maximum thickness of nearly 70 m. This mixed travertine-terrigenous succession was investigated in terms of lithofacies types, depositional environment and architecture and the variety of precipitated travertine fabrics. Deposited as beds with thickness ranging from centimetres to a few decimetres, carbonates include nine travertine facies types: F1) clotted peloidal micrite and microsparite boundstone, F2) raft rudstone/floatstone, F3) sub-rounded radial coated grain grainstone, F4) coated gas bubble boundstone, F5) crystalline dendrite cementstone, F6) laminated boundstone, F7) coated reed boundstone and rudstone, F8) peloidal skeletal grainstone and F9) calci-mudstone and microsparstone. Beds of terrigenous deposits with thickness varying from a decimetre to > 10 m include five lithofacies: F10) breccia, F11) conglomerate, F12) massive sandstone, F13) laminated sandstone and F14) claystone. The succession recorded the following three phases of evolution of the depositional setting: 1) At the base, a northward-thinning thermogene travertine terraced slope (Phase I, travertine slope lithofacies association, F1-F6) developed close to the extensional fault system, placed southward with respect to the travertine deposition. 2) In Phase II, the accumulation of travertines was interrupted by the deposition of colluvial fan deposits with a thickness of several metres (colluvial fan lithofacies association, F10 and F12), which consisted of massive breccias, adjacent to the alluvial plain lithofacies association (F11-F14) including massive claystone and sandstone and channelized

  9. Response of the diatom flora in the Gdańsk Basin (southern Baltic Sea) to eutrophication in the last century

    Science.gov (United States)

    Witak, Małgorzata

    2016-04-01

    The diatom flora in six short cores (length of 10-20 cm) taken from Gdańsk Basin, southern Baltic Sea, was analyzed in order to response of diatoms to environmental changes over the past 100 years. This study is a part of CLISED project (Climate Change Impact on Ecosystem Health - Marine Sediments Indicators) funded from Norway Grants in the Polish-Norwegian Research Programme. Three cores P116, M1 and P1 were retrieved from the Gdańsk Deep region, whereas P104, BMPK10 and P110 were drilled from the shallower part - Gulf of Gdańsk. The sediment cores were dated by 210Pb and represented time interval of AD 1895-2015. In this period an artificial mouth of the Vistula River near Świbno was excavated and riverine waters flowed directly to the Gulf of Gdańsk. Urbanization, progressive industrialization and an increase in the inflow of waste water had a strong influence on ecosystem in the last 120 years. The transport of large amounts of nutrients, organic matter and pollutants by the rivers resulted in environmental degradation of the Gdańsk Basin and its progressive eutrophication in particular. Diatoms, being the major component of algal assemblages, are excellent bioindicators for assessing the state of basin ecosystems. They are usually abundant in marine sediments, diverse and sensitive to numerous environmental variables, including physical (e.g. light, temperature, water transparency) and chemical (e.g. pH, alkalinity, nutrient availability) factors. Changes in nutrients concentrations may lead to substantial transformations in the structure of diatom assemblages. Samples for diatom analyses (ca. 0.3-2.0 g dry sediment) were prepared following the standard procedure for diatom observation under light microscope (Battarbee, 1986). To estimate the concentration of siliceous microfossils per unit weight of dry sediment (absolute abundance), a random settling technique was used (Bodén, 1991). Permanent diatom preparations were mounted in Naphrax® (refractive

  10. Seismic velocities within the sedimentary succession of the Canada Basin and southern Alpha-Mendeleev Ridge, Arctic Ocean: evidence for accelerated porosity reduction?

    Science.gov (United States)

    Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah R.

    2016-01-01

    The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity–depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity–depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity–depth profiles for each seismic trace. A thickness of 12–13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity–depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares

  11. Seismic velocities within the sedimentary succession of the Canada Basin and southern Alpha-Mendeleev Ridge, Arctic Ocean: evidence for accelerated porosity reduction?

    Science.gov (United States)

    Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah

    2016-01-01

    The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity-depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity-depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity-depth profiles for each seismic trace. A thickness of 12-13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity-depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares favourably with

  12. Peruánská gastronomie

    OpenAIRE

    Bočková, Petra

    2013-01-01

    The aim of this thesis is to characterize culture and gastronomy of Peru as a specific tourist destination. First part -- the theoretical one -- deals with explanation of main terms from the fields of tourism and gastronomy. Following parts include characteristics of Peru and its gastronomy. The second chapter, in particular, involves basic information about realia, geography and history of Peru, followed by characteristics of tourism in the country. The third chapter, first of all, explains ...

  13. Analysis of past and future oil production in Peru under a Hubbert approach

    International Nuclear Information System (INIS)

    This study evaluates scenarios for the oil production in Peru applying a Hubbert model. Two scenarios for the estimated ultimate recovery (EUR) were proposed: the first, in which low investments in E&P and social and environmental barriers undermine the development of oil resources beyond the limits characterized as 2P; the second, more optimistic, in which current exploratory and production areas in Amazonia and low-explored Offshore-Shelf basins are developed, thus, increasing EUR to 3P reserves plus contingent resources. Findings show that oil production in Peru has not followed a Single-Hubbert pattern, except for the area with more drilling activity and the highest accumulated production in the Northwest coast. Actually, institutional and regulation changes and less-attractive periods for operators due to poor results in oil discoveries explain why a multi-Hubbert approach better depicted the oil production in Peru. Peru has the potential to achieve a second peak of 274 kbpd of crude oil, overcoming the peak of 195 kbpd, reached in 1982. However, most of the remaining production would be located in Amazonia, where social and environmental issues pose critical challenges. - Highlights: • Two scenarios of estimated ultimately recoverable resources were simulated. • A multi-cycle Hubbert approach better depicted the case of oil production in Peru. • Pipelines expansion and institutional and regulation changes explain this multi-cyle. • Institutional capacity and socio-environmental risks are barriers to oil activities

  14. Jurassic onychites (hooks from squid-like cephalopods) associated with statolith occurrences in the Wessex Basin, southern England

    Science.gov (United States)

    Hart, Malcolm; Page, Kevin; Price, Gregory; Smart, Christopher; Wilby, Philip

    2016-04-01

    Modern coleoid (squid-like) cephalopods have arms that carry arrays of both suckers and hardened, organic hooks. Fossil arm hooks have been known since the description of Sternberg in 1823, although he identified them as plant remains. During the twentieth century there were a number of brief descriptions of hooks but it was Kulicki & Szaniawski (1972) who described 22 morphotypes from the Jurassic of Poland. These authors gave these 'forms' names using a binomial classification though, with many lacking defined (and figured) holotypes and, in some cases, only one recorded specimen, some of their designations should be regarded as invalid. Some of the morphotypes have, however, been reported from DSDP sites on the Falkland Plateau as well as New Zealand, Germany, Poland and the United Kingdom. It is clear that the hooks must belong to widely distributed members of the Belemnitida and Phragmoteuthida. Exceptional soft-bodied preservation of species such as Belemnotheutis antiquus from the Callovian-Oxfordian of the United Kingdom has allowed the identification of the host animal of some morphotypes, though the majority remain non-attributable. In the Christian Malford lagerstätte (Upper Callovian) of Wiltshire large numbers of hooks (including forms described as Acanthuncus, Arites, Deinuncus, Falcuncus, Longuncus and Paraglycerites) are found associated with an abundance of statoliths (cephalopod 'ear bones') and macrofossil evidence of both belemnites and teuthids, some of which includes exceptional soft-bodied preservation (see Wilby et al., 2004, 2008; Hart et al., in press). Using the abundance of material available to us from the Wessex Basin, we are attempting to identify, where possible, the host animals. If this can be established then it should be possible, using micropalaeontological samples, to determine the stratigraphical and palaeoecological ranges of some of the host macro-fossils, many of which are otherwise rarely preserved. HART, M.B., DE JONGHE

  15. Constraining the India-Asia collision by retrieving the paleolatitude from partially remagnetized Paleogene volcanics in the Nanmulin Basin (southern Tibet)

    Science.gov (United States)

    Huang, Wentao; Dupont-Nivet, Guillaume; van Hinsbergen, Douwe; Lippert, Peter; Dekkers, Mark; Guo, Zhaojie; Li, Xiaochun; Zhang, Xiaoran

    2014-05-01

    Determining paleolatitudes of the Lhasa terrane (southern Tibet) using paleomagnetic inclinations is key to constraining the paleogeography and timing of the collision between India and Asia. However, paleolatitude estimates vary widely from 5°N to 30°N due to unrecognized rock magnetic biases such as inclination shallowing in sedimentary rocks or poor averaging of secular variation in volcanic rocks. Here, we investigated Paleogene volcanics of the Linzizong Group from southern Tibet in the Nanmulin Basin that had previously yielded low paleomagnetic inclinations ca. 10°N. Using proper paleomagnetic sampling and measurement protocols we observe similar shallow inclinations. However, sampled sections with different bedding attitudes yield a negative fold test indicating that the isolated remanent magnetizations do not have a primary origin. Detailed rock magnetic analysis, end-member modeling, and petrographic investigation reveal that most of the section has been variably remagnetized due to low-temperature alteration of magmatic titanomagnetite and formation of secondary hematite, which occurred after tilting of the strata. We show that the observed paleomagnetic inclinations vary according to a linear trend with the degree of remagnetization. Accordingly, we can estimate that the primary pre-tilting thermoremanent magnetization has an inclination of 38.1° ([35.7°, 40.5°] within 95% confidence limit), corresponding to a paleolatitude of 21.4° ([19.8°, 23.1°] within 95% confidence limit). This is consistent with results from pristine volcanic units and inclination-shallowing corrected sediments of the upper Linzizong Group ~200 km to the east [Dupont-Nivet et al., Geophysical Journal International, 182, 1189-1198; Huang et al., Geophysical Journal International, 194, 1390-1411]. Our results demonstrate that previously reported low paleolatitudes of the Lhasa terrane can be an artifact of unrecognized remagnetization. Furthermore, we show that original

  16. The regulatory state in Peru

    OpenAIRE

    Parodi Trece, Carlos A.

    2014-01-01

    Significant institutional changes have taken place during the government of Alberto Fujimori. What is the meaning of these changes? Do they reflect Alberto Fujimori's strategy of power consolidation? Are they the result of the strategy of dominant economic classes to continue exploiting Peru's resources? Or are these institutions reflecting a process of democratization of the state?   This article explores these questions by examining state institutions in the area of public services. The arg...

  17. Natural Offshore Oil Seepage and Related Tarball Accumulation on the California Coastline - Santa Barbara Channel and the Southern Santa Maria Basin: Source Identification and Inventory

    Science.gov (United States)

    Lorenson, T.D.; Hostettler, Frances D.; Rosenbauer, Robert J.; Peters, Kenneth E.; Dougherty, Jennifer A.; Kvenvolden, Keith A.; Gutmacher, Christina E.; Wong, Florence L.; Normark, William R.

    2009-01-01

    Oil spillage from natural sources is very common in the waters of southern California. Active oil extraction and shipping is occurring concurrently within the region and it is of great interest to resource managers to be able to distinguish between natural seepage and anthropogenic oil spillage. The major goal of this study was to establish the geologic setting, sources, and ultimate dispersal of natural oil seeps in the offshore southern Santa Maria Basin and Santa Barbara Basins. Our surveys focused on likely areas of hydrocarbon seepage that are known to occur between Point Arguello and Ventura, California. Our approach was to 1) document the locations and geochemically fingerprint natural seep oils or tar; 2) geochemically fingerprint coastal tar residues and potential tar sources in this region, both onshore and offshore; 3) establish chemical correlations between offshore active seeps and coastal residues thus linking seep sources to oil residues; 4) measure the rate of natural seepage of individual seeps and attempt to assess regional natural oil and gas seepage rates; and 5) interpret the petroleum system history for the natural seeps. To document the location of sub-sea oil seeps, we first looked into previous studies within and near our survey area. We measured the concentration of methane gas in the water column in areas of reported seepage and found numerous gas plumes and measured high concentrations of methane in the water column. The result of this work showed that the seeps were widely distributed between Point Conception east to the vicinity of Coal Oil Point, and that they by in large occur within the 3-mile limit of California State waters. Subsequent cruises used sidescan and high resolution seismic to map the seafloor, from just south of Point Arguello, east to near Gaviota, California. The results of the methane survey guided the exploration of the area west of Point Conception east to Gaviota using a combination of seismic instruments. The

  18. Late Norian δ13Corg record in the Tethyan realm: New clues on the complex Late Triassic carbon cycle from the Lagonegro Basin (southern Italy)

    Science.gov (United States)

    Zaffani, Mariachiara; Agnini, Claudia; Concheri, Giuseppe; Godfrey, Linda; Katz, Miriam; Maron, Matteo; Rigo, Manuel

    2016-04-01

    The Late Triassic (ca. 237-201 Ma) is characterized by complex and extreme environmental, climatic and biotic changes (e.g.: the break-up of the supercontinent Pangaea; the humid event known as the Carnian Pluvial Event; the End-Triassic mass extinction; the emplacement of the CAMP volcanism). A global δ13Corg curve for the Late Triassic would provide new clues on this perturbed time interval and would have the potential for global correlations. In particular, the few available data from North American successions define the late Norian (ca. 220-206 Ma) as a "chaotic carbon interval", with rapid vacillations of the carbon isotope values paired with low faunal diversity. Our goal is to reconstruct a global δ13Corg profile for the late Norian, as a contribution to the construction of a more complete global carbon isotope curve for the Late Triassic. For this purpose, we analyzed three sections from the Lagonegro Basin (southern Italy), originally located in the western Tethys, on the other side of the supercontinent Pangaea respect to the North America. The obtained δ13Corg profiles show four negative shifts correlatable with those of the North American record, suggesting that these carbon cycle perturbations have a widespread occurrence. These perturbations are associated with negative shifts of the 87Sr/86Sr, indicating that these global δ13Corg and 87Sr/86Sr negative excursions were possibly caused by emplacement of a Large Igneous Province (LIP). The input of volcanogenic CO2 to the atmosphere-ocean system is supported also by the 12C enrichment observed, as well as by the increase of atmospheric pCO2 inferred by different models for the Norian- Rhaetian interval. This Norian magmatic activity may be ascribed to the Angayucham province (Alaska, North America), a large oceanic plateau active ca. 214 Ma ±7 Myr, with an estimated volume comparable to other two Late Triassic LIPs: the Wrangellia and the CAMP.

  19. Kaolinite, illite and quartz dissolution in the karstification of Paleozoic sandstones of the Furnas Formation, Paraná Basin, Southern Brazil

    Science.gov (United States)

    Melo, Mário Sérgio de; Guimarães, Gilson Burigo; Chinelatto, Adilson Luiz; Giannini, Paulo César Fonseca; Pontes, Henrique Simão; Chinelatto, Adriana Scoton Antonio; Atencio, Daniel

    2015-11-01

    Karstification processes in sandstones of the Furnas Formation, Silurian to Devonian of the Paraná Basin, have been described since the mid-twentieth century. However, some geologists still doubt the idea of true karst in sandstones. Studies carried out in the Campos Gerais region, Paraná State, Southern Brazil, aimed at investigating the nature of erosion processes in Furnas Formation and the role of the dissolution in the development of their notorious erosive features and underground cavities. These studies have led to the recognition of dissolution macro to micro features ('furnas', caves, ponds, sinks, ruiniform relief on cliffs and rocky surfaces, grain corrosion, speleothems, mineral reprecipitation and incrustation). The analysis (scanning electron microscopy, energy dispersive spectrometry and x-ray diffractometry) of sandstones and their alterites has indicated significant dissolution of clay cement along with discrete quartz grain dissolution. This mesodiagenetic cement (kaolinite and illite) is dissolved and reprecipitated as clay minerals with poorly developed crystallinity along with other minerals, such as variscite and minerals of the alunite supergroup, suggesting organic participation in the processes of dissolution and incrustation. The mineral reprecipitation usually forms centimetric speleothems, found in cavities and sheltered rocky surfaces. The cement dissolution associated with other factors (fractures, wet weather, strong hydraulic gradient, antiquity of the landforms) leads to the rock arenisation, the underground erosion and the appearance of the karst features. Carbonate rocks in the basement may locally be increasing the karst forms in the overlying Furnas Formation. The recognition of the karst character of the Furnas Formation sandstones has important implications in the management of underground water resources (increasingly exploited in the region), in the use of the unique geological heritage and in the prevention of geo

  20. Spatio-Temporal Analysis of Model and Satellite Based Soil Moisture Estimations for Assessing Coupling Hot Spots in the Southern La Plata Basin

    Science.gov (United States)

    Bruscantini, C. A.; Karszenbaum, H.; Ruscica, R. C.; Spennemann, P.; Salvia, M.; Sorensson, A. A.; Grings, F. M.; Saulo, C.

    2015-12-01

    The southern La Plata Basin, located in southeastern South America (SESA), a region of great importance because of its hydrological characteristics, the fact that it has the largest population density and is one of the most productive regions in terms of agriculture, cattle raising and industry of the continent, has been identified as a strong hotspot between soil moisture (SM) and the atmosphere by different regional studies. Among them, Ruscica et al. (2014, Atmos. Sci. Let, Int. J. Climatol.), and Spennemann et al. (2015, Int. J. Climatol.) show, through different modeling approaches, the presence of strong soil moisture-precipitation and evapotranspiration interactions during austral summer in SESA, revealing similar hotspots. Nevertheless these studies have diverse limitations related to model assumptions and to vegetation parameterizations, as well as the lack of observational data for the evaluation of models performance (Ferguson and Wood, 2011, J. of Hydrometeorology). On the other hand, in the last decade several instruments on board satellites are providing soil moisture products globally and in a continuous way. A recent work by Grings et al. (2015, IEEE JSTARS, in press), done over the Pampas Plains in SESA showed characteristic soil moisture patterns that follow the Standardized Precipitation Index (SPI) under extreme wet and dry conditions In order to deepen and overcome some of the mentioned model limitations, this work adds satellite soil moisture and vegetation products in the spatio-temporal analysis of the regions of strong soil moisture-atmosphere interactions. The main objectives and related outcomes are: the verification of already identified regions where soil moisture anomalies may have an influence on subsequent precipitation, evapotranspiration and temperature anomalies, and the study of their seasonal characteristics and land cover influences.

  1. Peru : Overcoming the Barriers to Hydropower

    OpenAIRE

    World Bank

    2010-01-01

    Hydropower has been the major source of electricity in Peru, traditionally supplying more than 80 percent of electricity requirements, and serving as a source of independent generation for major mines and industries. With the development of natural gas in the early 1990s, and the opening of the Camisea pipeline, the Government of Peru's (GOP's) attention turned to providing incentives for ...

  2. New Trends in Talent Development in Peru

    Science.gov (United States)

    Blumen, Sheyla

    2013-01-01

    A comprehensive portrait of the current status of gifted and talented concepts, identification of the gifted, and associated provisions within Peru is presented. The major purposes of this article are (a) to analyze the primary conception of giftedness in Peru; (b) to describe the beliefs that people have about gifted individuals; (c) to present…

  3. DIVERSITY OF CARABIDS (COLEOPTERA) ASSOCIATED WITH THE LOWER LURIN RIVER, LIMA, PERU

    OpenAIRE

    ARMANDO VÉLEZ-AZAÑERO; Alfonso Lizárraga-Travaglini

    2013-01-01

    Quarterly samples of beetles (Coleoptera: Carabidae) were taken associated with the lower basin of the Lurín River (Lima-Peru) during the period August 2009 - February 2011, in six sampling points between 5 and 51 masl. Pitfall traps were used and obtained a total of 59 specimens distributed among three tribes, three genera, and four morphospecies. We report the presence of Megacephala, Scarites genus, and Pterostichus with the latter being the predominant genus.

  4. First thoughts on surface tonal patterns in Amawaka, a Panoan language of Peru and Brazil

    OpenAIRE

    2014-01-01

    Amawaka ([ɑmɨ̃ˈwɐkɑ]) is a highly endangered and underdocumented tonal language of the Headwaters (Fleck 2011) subgroup of the Panoan family in the Southwest Amazon Basin, spoken by approximately 200 people. Undocumented phonetic and phonological phenomena of Amawaka include its tonal structure, both in terms of surface realizations and the patterns underlying these realizations. Original audiovisual data from the author’s fieldwork in various Amawaka communities at the Peru-Brazil border wil...

  5. Geomorphic evidences of recent tectonic activity in the forearc, southern Peru Evidencias geomórficas de actividad tectónica reciente en el Antearco Perú sur

    Directory of Open Access Journals (Sweden)

    L. Audin

    2006-12-01

    Full Text Available As the Andean forearc is not concentrating as much tectonic shortening as the foreland (since Middle Miocene and as GPS measurements can not inform on the long-term deformation but rather describe the elastic response of the Andean forearc (Nazca-South American convergence, little is known about the active deformation in the Central Andes Pacific lowlands. However, geomorphic evidences of recent tectonic activity are observed from the Coastal Cordillera to the piedmont of the Western Cordillera. In this paper we analyze this Quaternary tectonic activity in the southern Peruvian forearc, from 17°S to 18°30'S. Examination of aerial photographs and satellite data, and focused field work not only confirms that there is recent tectonic activity but also has revealed the presence of additional active structures that should be taken into account in the description of Andean deformation. In response to active tectonics, these tectonic structures affected very young terraces and Quaternary pediments in the southern Peruvian forearc. We discuss some of the strong geomorphic signatures, such as active fault traces, scarplets, sag ponds, river terraces and some major and minor landslides, which are indicative of active tectonics in this area. Mapping of fault trace geometry and identifying recent surface offsets are used to determine the key places where active tectonics can be involved in the deformation of the forearc, either through normal faulting, strike-slip faults or thrust faults. Among those major tectonic features, some are likely due to seismic crustal activity (along the ongoing Andean tectonic processes and some to relaxation processes of the stress imposed on the outer forearc area after each major subduction earthquakes.Debido a que el antearco andino no está concentrando tanto acortamiento como el antepaís (desde el Mioceno Medio y como las mediciones de GPS no pueden dar información de la deformación de largo plazo sino que más bien

  6. New mammalian records in the Parque Nacional Cerros de Amotape, northwestern Peru

    OpenAIRE

    Cindy M. Hurtado; Víctor Pacheco

    2015-01-01

    The Pacific Tropical Rainforest and Equatorial Dry Forest are found only in southern Ecuador and northern Peru, and are among the most poorly known ecosystems of South America. Even though these forests are protected in Parque Nacional Cerros de Amotape (PNCA), they are threatened by fragmentation because of farming and agriculture. The aim of this study was to determine the medium and large mammalian species richness, using transect census, camera trapping, and specimen bone collection. Nine...

  7. Paleomobility in the Tiwanaku diaspora: biogeochemical analyses at Rio Muerto, Moquegua, Peru.

    Science.gov (United States)

    Knudson, Kelly J; Goldstein, Paul S; Dahlstedt, Allisen; Somerville, Andrew; Schoeninger, Margaret J

    2014-11-01

    Paleomobility has been a key element in the study of the expansion of ancient states and empires, including the Tiwanaku polity of the South Central Andes (AD 500-1000). We present radiogenic strontium and oxygen isotope data from human burials from three cemeteries in the Tiwanaku-affiliated Middle Horizon archaeological site complex of Rio Muerto in the Moquegua Valley of southern Peru. At Rio Muerto, archaeological human enamel and bone values range from (87) Sr/(86) Sr = 0.70657-0.72018, with a mean of (87) Sr/(86) Sr = 0.70804 ± 0.00207 (1σ, n = 55). For the subset of samples analyzed for oxygen isotope values (n = 48), the data ranges from δ(18) Ocarbonate(VSMOW)  = +18.1 to +27.0‰. When contextualized with other lines of archaeological evidence, we interpret these data as evidence for an archaeological population in which the majority of individuals had "local" origins, and were likely second-generation, or more, immigrants from the Tiwanaku heartland in the altiplano. Based on detailed life history data, we argue a smaller number of individuals came at different ages from various regions within the Tiwanaku polity. We consider whether these individuals with isotopic values consistent with "nonlocal" geographic origins could represent first-generation migrants, marriage exchange partners, or occupationally mobile herders, traders or other travelers. By combining isotopic life history studies with mortuary treatment data, we use a person-centered migration history approach to state integration and expansion. Isotopic analyses of paleomobility at the Rio Muerto site complex contribute to the role of diversity in ancient states by demonstrating the range of geographic origins rather than simply colonists from the Lake Titicaca Basin. PMID:25066931

  8. Population structure and reproduction of Deuterodon langei travassos, 1957 (Teleostei, Characidae in a neotropical stream basin from the Atlantic Forest, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Jean Ricardo Simões Vitule

    2008-12-01

    Full Text Available Aspects of the biology of D. langei were studied at different sites along a longitudinal gradient formed by the Ribeirão stream basin, a Neotropical stream of the Atlantic Forest, southern Brazil. Differences were observed in population structure and reproduction along the longitudinal gradient and during the study period. Juvenile fishes occurred in high abundance, mainly in the downstream site after the rainy months. Adults occurred mainly in the intermediate and upstream sites. During their life cycle, adults optimise their reproductive strategy by concentrating the reproductive period with total spawn in a short time interval before summer rains dragged the juvenile, larval forms and/or eggs downstream. The downstream site was characterized by a wide range of microhabitats (ex. submerged grass and shallow flooded area. Thus, the species used different portions of the basin in distinct stages of its life, being ecologically adapted to variation patterns in its temporal and physical environments.Aspectos da biologia de D. langei foram estudados em diferentes locais da bacia do rio Ribeirão, um riacho litorâneo da Floresta Atlântica do sudeste do Brasil. Foram observadas diferenças na estrutura da população e na reprodução, ao longo do gradiente longitudinal da bacia e do período de estudo. Os peixes juvenis ocorreram em grande abundância, principalmente no trecho a jusante da bacia, após os meses mais chuvosos. Adultos ocorreram principalmente nos trechos intermediários e a montante. Não houve diferença significativa na relação sexual entre os locais amostrados, estações do ano, meses e classes de comprimento. O comprimento médio de primeira maturação (L50 foi o mesmo para machos e fêmeas, entre 6,1 e 7,0 cm de comprimento total (Lt. O período reprodutivo foi curto (entre o final da primavera e início do verão, antes dos meses mais chuvosos, com desova total. O Índice de Atividade Reprodutiva (IAR indicou que D

  9. Interpretation of an airborne geophysical survey in southern Paris Basin: towards a lithological cartography, key tool for the management of shrinking/swelling clay problems

    Science.gov (United States)

    Prognon, F.; Tourliere, B.; Perrin, J.; Lacquement, F.; Martelet, G.; Deparis, J.; Gourdier, S.; Drufin, S.

    2011-12-01

    Regolith formations support a full spectrum of human activities. Among others, they provide a source of extractable materials and form the substratum of soils. As such, they should be considered as a capital to be managed and protected. Moreover, one of the main challenges for present and future land settlement is to prevent house building programs from being planned inside shrink-swell risky areas which is only possible thanks to an complete lithological mapping of the french regolith. We illustrate here the results of the geological interpretation of an airborne geophysical survey carried out in "Région Centre" administrative region in the southern part of the Paris Basin, in France. Among other techniques, airborne geophysics is appropriate to quickly provide information on near surface, because of i) its high spatial coverage ii) the rapidity of acquisition and iii) the variety of available sensors (magnetic, spectral radiometry, electromagnetic...). Spectral radiometry data were collected with a line spacing of 1 km. This method provides maps of potassium (K), uranium (U) and thorium (Th) which are the only naturally occurring elements with direct or indirect radioisotopes that produce gamma rays of sufficient intensity to be measured at airborne survey heights. On the radiometric data we applied the HAC (Hierarchical Ascendant Classification) computation procedure: taking into account several variables, the statistical HAC method groups individuals based on their resemblance. Also in this study, calibrated Total Count channel (TCm) is compared to an estimated dose rate (TCe) computed from the measured radioelement abundances: TCe = 13.078 * K + 5.675 * U + 2.494 * Th. Our results show that the ratio TCe/TCm came out to be a good indicator of ground property changes within Sologne mixed sandy-clay environment. Processed geophysical data are cross-checked with geological data (from field observations) and field or laboratory measurements of mineralogical data

  10. Pragmatic consideration of geologic carbon storage design based upon historic pressure response to oil and gas production in the southern San Joaquin basin

    Science.gov (United States)

    Jordan, P. D.

    2015-12-01

    Annual CO2 emissions from large fixed sources in the southern San Joaquin Valley and vicinity in California are about 20 million metric tons per year (MMT/Y). Cumulative net fluid production due to oil and gas extracted from below the minimum depth for geologic carbon storage (taken as 1,500 m) was 1.4 billion m3 at reservoir conditions as of 2010. At an average CO2 storage density of 0.5 metric tons per m3, this implies 35 years of storage capacity at current emission rates just to refill the vacated volume, neglecting possible reservoir consolidation. However, the production occurred from over 300 pools. The production rate relative to average pressure decline in the more productive pools analyzed suggests they could receive about 2 MMT/Y raising the field average pressure to nearly the fracturing pressure. This would require well fields as extensive as those used for production, instead of the single to few wells per project typically envisioned. Even then, the actual allowable injection rate to the larger pools would be less than 2 MMT/Y in order to keep pressures at the injection well below the fracture pressure. This implies storing 20 MMT/Y would require developing storage operations in tens of pools with hundreds, if not over a thousand, wells. This utilization of one of the basins with the most storage capacity in the state would result in reducing the state's fixed source emissions by only one eighth relative to current emissions. The number of fields and wells involved in achieving this suggests a different strategy might provide more capacity at similar cost. Specifically, staging wells that initially produce water in the vicinity of fewer injection wells could result in both more storage. This water could be directed to a shallower zone, or supplied to the surface at a similar cost. The commencement of ocean water desalination in the state indicates the economics of water supply might support treating this water for beneficial use, particularly if it

  11. On the wave energy resource of Peru

    International Nuclear Information System (INIS)

    Highlights: • The wave energy resource of Peru was assessed for the first time. • Peru has a moderate to high offshore wave energy resource. • The south coast of Peru has a higher wave energy potential than the north coast. • The Peruvian wave energy resource has low temporal variations. • The wave energy resource exceeds by seven times electric power demand in Peru. - Abstract: This is the first assessment of the wave energy resource in Peru, an emerging country with an increasing energy demand and a high dependence on fossil fuels. On the basis of wave buoy measurements, we characterize the offshore wave energy resource and analyze its temporal variability, comparing the results with those obtained in previous works for other regions. A wave propagation numerical model (SWAN) is used to determine the nearshore spatial distribution of wave energy. A total of 357 offshore sea states, representing 90% of the wave energy and 94% of the time in an average year, were propagated. The wave energy in Peru presents a resource exceeding by more than seven times the total electric demand of the country. Because of the large amount of resource available and its low seasonal variation, wave energy must be considered in Peru as an alternative to conventional energy resources

  12. Digital model of the seabed geomorphology of southern-central Espirito Santo basin and northern Campos basin; Modelo digital da geomorfologia do fundo oceanico do centro-sul da bacia do Espirito Santo e norte da bacia de Campos

    Energy Technology Data Exchange (ETDEWEB)

    Schreiner, Simone; Souza, Mariana Beatriz Ferraz Mendonca de; Migliorelli, Joana Paiva Robalo [Petroleo Brasileiro S. A. (PETROBRAS), Rio de Janeiro, RJ (Brazil). Unidade de Servicos de Exploracao e Producao], Emails: schreiner@petrobras.com.br, mbfms.fototerra@petrobras.com.br, joanamigli.fototerra@petrobras.com.br

    2009-05-15

    That communication brings the result of a bathymetric mosaic of converted in a digital model of the ocean topography, consisting of 17 seismic projects 3D, besides 17 multibeam bathymetry surveys of South-Central Espirito Santo Basin and Northern Campos Basin.

  13. Distribution and morphological variation of Eleutherodactylus mercedesae Lynch & McDiarmid, 1987 (Amphibia, Anura, Leptodactylidae) with first record for Peru

    Science.gov (United States)

    Padial, J.M.; McDiarmid, R.; De la Riva, I.

    2006-01-01

    We report new distributional information for Eleutherodactylus mercedesae in Bolivia, and provide the first record for Peru based on an adult female. This species, previously endemic to Bolivia, now ranges across about 1000 km in cloud forests on the Amazonian slopes of the Andes from southern Peru to central Bolivia. We provide the first morphological description of females based on two specimens, compare them with the male type and paratype, add some observations to the original description, and comment on variation in the species.

  14. Infrastructure and economic growth in Peru

    OpenAIRE

    Roberto Urrunaga; Carlos Aparicio

    2012-01-01

    This article reviews the literature analysing the importance of infrastructure for economic growth, and performs an econometric estimation to discover the relation between the two variables in the case of Peru. Different estimators are used with panel data from the 24 regions of Peru for the period 1980-2009. The econometric results confirm that public-service infrastructures (roads, electricity and telecommunications) are important in explaining temporary differences in regional output, in k...

  15. Currency Substitution and Inflation in Peru

    OpenAIRE

    Liliana Rojas-Suárez

    1992-01-01

    This paper shows that there is a long-run relationship between the expected rate of depreciation in the black-market-exchange rate and the ratio of domestic to foreign money in Peru; that is, the hypothesis of currency substitution can explain the behavior of real holdings of money in Peru. The paper also shows that, while the importance of currency substitution as a transmission mechanism through which domestic policies affected the dynamics of inflation was relatively small during a period ...

  16. The Giant Otter Project In Peru 1995

    Directory of Open Access Journals (Sweden)

    Christof Schenck

    1995-10-01

    Full Text Available Giant Otters (Pteronura brasiliensis are rarely investigated but highly endangered. The project "STATUS, HABITAT AND CONSERVATION OF GIANT OTTERS IN PERU" from the Frankfurt Zoological Society, - Help for Threatened Wildlife - started in 1990 with a two and half year fieldwork period. The project is actually run with a yearly two months fieldwork period in Peru and ongoing analyzing, management and coordination from Germany. Following we give the report for 1995.

  17. Metropolitan growth and migration in Peru

    OpenAIRE

    Malmberg, Gunnar

    1988-01-01

    Abstract: The study deals with the interplay between migration and metropolitan growth in Peru during the last decades. The key question is to what extent Peru's rural-urban migration and rapid urban growth is triggered by opportunities within the formal and informal sectors in the growing metropolis of Lima. Aggregated data about migration have been related to information of socioeconomic and geographical conditions in rural and urban areas. Multivariate models of interregional migration are...

  18. [The health system of Peru].

    Science.gov (United States)

    Alcalde-Rabanal, Jacqueline Elizabeth; Lazo-González, Oswaldo; Nigenda, Gustavo

    2011-01-01

    This paper describes the health conditions in Peru and, with greater detail, the Peruvian health system, including its structure and coverage, its financial sources, its physical, material and human resources, and its stewardship functions. It also discusses the activities developed in the information and research areas, as well as the participation of citizens in the operation and evaluation of the health system. The article concludes with a discussion of the most recent innovations, including the Comprehensive Health Insurance, the Health Care Enterprises system, the decentralization process and the Local Committees for Health Administration. The main challenge confronted by the Peruvian health system is the extension of coverage to more than I0% of the population presently lacking access to basic health care. PMID:21877089

  19. The thermal history of the Miocene Ibar Basin (Southern Serbia: new constraints from apatite and zircon fission track and vitrinite reflectance data

    Directory of Open Access Journals (Sweden)

    Andrić Nevena

    2015-02-01

    Full Text Available The Ibar Basin was formed during Miocene large scale extension in the NE Dinaride segment of the Alpine- Carpathian-Dinaride system. The Miocene extension led to exhumation of deep seated core-complexes (e.g. Studenica and Kopaonik core-complex as well as to the formation of extensional basins in the hanging wall (Ibar Basin. Sediments of the Ibar Basin were studied by apatite and zircon fission track and vitrinite reflectance in order to define thermal events during basin evolution. Vitrinite reflectance (VR data (0.63-0.90 %Rr indicate a bituminous stage for the organic matter that experienced maximal temperatures of around 120-130 °C. Zircon fission track (ZFT ages indicate provenance ages. The apatite fission track (AFT single grain ages (45-6.7 Ma and bimodal track lengths distribution indicate partial annealing of the detrital apatites. Both vitrinite reflectance and apatite fission track data of the studied sediments imply post-depositional thermal overprint in the Ibar Basin. Thermal history models of the detritial apatites reveal a heating episode prior to cooling that began at around 10 Ma. The heating episode started around 17 Ma and lasted 10-8 Ma reaching the maximum temperatures between 100-130 °C. We correlate this event with the domal uplift of the Studenica and Kopaonik cores where heat was transferred from the rising warm footwall to the adjacent colder hanging wall. The cooling episode is related to basin inversion and erosion. The apatite fission track data indicate local thermal perturbations, detected in the SE part of the Ibar basin (Piskanja deposit with the time frame ~7.1 Ma, which may correspond to the youngest volcanic phase in the region.

  20. New results on ground deformation in the Upper Silesian Coal Basin (southern Poland) obtained during the DORIS Project (EU-FP 7)

    Science.gov (United States)

    Graniczny, Marek; Colombo, Davide; Kowalski, Zbigniew; Przyłucka, Maria; Zdanowski, Albin

    2015-11-01

    This paper presents application of satellite interferometric methods (persistent scatterer interferometric synthetic aperture radar (PSInSAR™) and differential interferometric synthetic aperture radar (DInSAR)) for observation of ground deformation in the Upper Silesian Coal Basin (USCB) in Southern Poland. The presented results were obtained during the DORIS project (EC FP 7, Grant Agreement n. 242212, www.doris-project.eu). Several InSAR datasets for this area were analysed. Most of them were processed by Tele-Rilevamento Europa - T.R.E. s.r.l. Italy. Datasets came from different SAR satellites (ERS 1 and 2, Envisat, ALOS- PALSAR and TerraSAR-X) and cover three different SAR bands (L, C and X). They were processed using both InSAR techniques: DInSAR, where deformations are presented as interferometric fringes on the raster image, and PSInSAR, where motion is indentified on irregular set of persistent scatterer (PS) points. Archival data from the C-band European Space Agency satellites ERS and ENVISAT provided information about ground movement since 1992 until 2010 in two separate datasets (1992-2000 and 2003-2010). Two coal mines were selected as examples of ground motion within inactive mining areas: Sosnowiec and Saturn, where mining ceased in 1995 and 1997, respectively. Despite well pumping after closure of the mines, groundwater rose several dozen meters, returning to its natural horizon. Small surface uplift clearly indicated on satellite interferometric data is related to high permeability of the hydrogeological subregion and insufficient water withdrawal from abandoned mines. The older 1992-2000 PSInSAR dataset indicates values of ground motion ranging from -40.0 to 0.0 mm. The newer 2003-2010 dataset shows values ranging from -2.0 to +7.0 mm. This means that during this period of time subsidence was less and uplift greater in comparison to the older dataset. This is even more evident in the time series of randomly selected PS points from both coal

  1. A Multi-disciplinary Overview of Chagas in Periurban Peru

    Directory of Open Access Journals (Sweden)

    Sarah McCune

    2010-04-01

    Full Text Available There are between 8 and 11 million cases of America Human Trypanosomiasis, commonly known as Chagas disease, in Latin America. Chagas is endemic in southern Peru, especially the Arequipa region, where it has expanded from poor, rural areas to periurban communities. This paper summarizes the findings of four studies in periurban Arequipa: on determinants of disease-vector infestation; on prevalence, spatial patterns, and risk factors of Chagas; on links between migration, settlement patterns, and disease-vector infestation; and on the relationship between discordant test results and spatially clustered transmission hotspots. These studies identified two risk factors associated with the disease: population dynamics and the urbanization of poverty. Understanding the disease within this new urban context will allow for improved public health prevention efforts and policy initiatives. Discovered in 1909 by Brazilian physician Carlos Chagas, American Human Trypanosomiasis is a chronic and potentially life-threatening illness found throughout Latin America (Moncayo, 2003. Indeed, it is estimated that there are between 8 and 11 million cases in Mexico and Central and South America (Centers for Disease Control [CDC], 2009. Chagas disease, as it is most commonly known, is endemic in southern Peru, especially in the region of Arequipa. Once thought to be limited to poor, rural areas, the disease is now appearing in the periurban communities that surround Arequipa City, the capital of the region (Cornejo del Carpio, 2003. Understanding the urbanization of Chagas disease will allow public health and medical professionals to better combat the further transmission of the disease. After providing an overview of Chagas and introducing the scope of the disease in Latin America, this paper will summarize the findings of four recent studies conducted in periurban districts in Arequipa. Ultimately, this paper seeks to identify the risk factors associated with Chagas

  2. Republic of Peru - Environmental Sustainability : A Key to Poverty Reduction in Peru

    OpenAIRE

    World Bank

    2007-01-01

    This report on a key to poverty reduction in Peru identifies a number of cost-effective policy interventions that could be adopted in the short and medium term to support sustainable development goals as the Government of Peru attempts to combat the problems of inadequate water supply, sanitation and hygiene; urban air pollution; natural disasters; lead exposure; indoor air pollution; land...

  3. Dominação, resistencia e autonomia no extremo sul do Vice-reinado do Peru (Séculos XVI e XVII - 10.4025/dialogos.v13i2.410 Dominación, resistencia y autonomía en el extremo sur del Virreinato del Perú (siglos XVI y XVII Domination, resistance and autonomy in the far southern Viceroyalty of Peru (16th and 17th centuries - doi: 10.4025/dialogos.v13i2.410

    Directory of Open Access Journals (Sweden)

    Beatriz Bixio

    2010-08-01

    Full Text Available Num contexto de ampla desestruturação das sociedades indígenas originarias da jurisdição de Córdoba, na antiga Governação de Tucumán, no extremo sul do Vice-reinado do Peru, indaga-se sobre os limites da dominação e sobre as possíveis margens que as populações nativas tiveram para negociar suas respectivas posições no interior do sistema. Com este objetivo, são analisadas as práticas de resistência indígena e as mudanças operadas nelas entre fins do século XVI e fins do XVII. Coloca-se especial atenção nas micro práticas ou “táticas do débil”, entendidas como pequenas operações realizadas desde o lugar do outro eescassamente planejadas. Estas táticas não eram articuladas nem se inseriam num projeto global de resistência, mas conseguiram tremer as bases do poder.En un contexto de amplia desestructuración de las sociedades indígenas originarias de la jurisdicción de Córdoba en la antigua Gobernación del Tucumán (extremo sur del Virreinato del Perú, se indaga en los límites de la dominación colonial y en los posibles márgenes que tuvieron las poblaciones autóctonas para negociar sus respectivas posiciones en el interior del sistema. Con este objeto, se analizan las prácticas de resistencia indígena y las modificaciones sufridas en ellas desde fines del siglo XVI y hasta fines del siglo XVII. Se pone el acento particularmente en las microprácticas o “tácticas del débil” entendidas como pequeñas operaciones realizadas desde el lugar del otro y escasamente planificadas. Estas tácticas no se encontraban articuladas ni formaban parte de un proyecto global de resistencia pero lograron producir algunas sacudidas a los cimientos del poder.In a context of wide de-structuring of indigenous societies from the Cordoba jurisdiction in the former Tucuman Governorship, far southern Viceroyalty of Peru, this work questions the limits of domination and the possible freedoms the native populations had in

  4. Joint Peru/United States report on Peru/United States cooperative energy assessment. Volume 2. Annex 1

    Energy Technology Data Exchange (ETD