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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. Andes Hantavirus Variant in Rodents, Southern Amazon Basin, Peru

    OpenAIRE

    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

    2014-01-01

    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.

  3. Four-thousand-year-old gold artifacts from the Lake Titicaca basin, southern Peru.

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    Aldenderfer, Mark; Craig, Nathan M; Speakman, Robert J; Popelka-Filcoff, Rachel

    2008-04-01

    Artifacts of cold-hammered native gold have been discovered in a secure and undisturbed Terminal Archaic burial context at Jiskairumoko, a multicomponent Late Archaic-Early Formative period site in the southwestern Lake Titicaca basin, Peru. The burial dates to 3776 to 3690 carbon-14 years before the present (2155 to 1936 calendar years B.C.), making this the earliest worked gold recovered to date not only from the Andes, but from the Americas as well. This discovery lends support to the hypothesis that the earliest metalworking in the Andes was experimentation with native gold. The presence of gold in a society of low-level food producers undergoing social and economic transformations coincident with the onset of sedentary life is an indicator of possible early social inequality and aggrandizing behavior and further shows that hereditary elites and a societal capacity to create significant agricultural surpluses are not requisite for the emergence of metalworking traditions.

  4. Direct evidence of 1,900 years of indigenous silver production in the Lake Titicaca Basin of Southern Peru.

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    Schultze, Carol A; Stanish, Charles; Scott, David A; Rehren, Thilo; Kuehner, Scott; Feathers, James K

    2009-10-13

    Archaeological excavations at a U-shaped pyramid in the northern Lake Titicaca Basin of Peru have documented a continuous 5-m-deep stratigraphic sequence of metalworking remains. The sequence begins in the first millennium AD and ends in the Spanish Colonial period ca. AD 1600. The earliest dates associated with silver production are 1960 + or - 40 BP (2-sigma cal. 40 BC to AD 120) and 1870 + or - 40 BP (2-sigma cal. AD 60 to 240) representing the oldest known silver smelting in South America. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis of production debris indicate a complex, multistage, high temperature technology for producing silver throughout the archaeological sequence. These data hold significant theoretical implications including the following: (i) silver production occurred before the development of the first southern Andean state of Tiwanaku, (ii) the location and process of silverworking remained consistent for 1,500 years even though political control of the area cycled between expansionist states and smaller chiefly polities, and (iii) that U-shaped structures were the location of ceremonial, residential, and industrial activities.

  5. New age constraints on the palaeoenvironmental evolution of the late Paleozoic back-arc basin along the western Gondwana margin of southern Peru

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    Boekhout, F.; Reitsma, M. J.; Spikings, R.; Rodriguez, R.; Ulianov, A.; Gerdes, A.; Schaltegger, U.

    2018-03-01

    The tectonic evolution of the western Gondwana margin during Pangaea amalgation is recorded in variations in the Permo-Carboniferous back-arc basin sedimentation of Peru. This study provides the first radiometric age constraints on the volcanic and sedimentary sequences of south-central eastern Peru up to the western-most tip of Bolivia, and now permits the correlation of lateral facies variations to the late Paleozoic pre-Andean orogenic cycle. The two phases of Gondwanide magmatism and metamorphism at c. 315 Ma and c. 260 Ma are reflected in two major changes in this sedimentary environment. Our detrital U-Pb zircon ages demonstrate that the timing of Ambo Formation deposition corroborates the Late Mississipian age estimates. The transition from the Ambo to the Tarma Formation around the Middle Pennsylvanian Early Gondwanide Orogeny (c. 315 Ma) represents a relative deepening of the basin. Throughout the shallow marine deposits of the Tarma Formation evidence for contemporaneous volcanism becomes gradually more pronounced and culminates around 312 - 309 Ma. Continuous basin subsidence resulted in a buildup of platform carbonates of the Copacabana Formation. Our data highlights the presence of a previously unrecognized phase of deposition of mainly fluvial sandstones and localized volcanism (281-270 Ma), which we named ´Oqoruro Formation'. This sedimentary succession was previously miss-assigned to the so-called Mitu Group, which has recently been dated to start deposition in the Middle Triassic (∼245-240 Ma). The emersion of this marine basin coincides with the onset of a major plutonic pulse related to the Late Gondwanide Orogeny (c. 260). Exhumation lead to the consequent retreat of the epeiric sea to the present-day sub-Andean region, and the coeval accumulation of the fluvial Oqoruro Formation in south eastern Peru. These late Paleozoic palaeoenvironmental changes in the back-arc basins along the western Gondwana margin of southern reflect changes in

  6. Late Archaic–Early Formative period microbotanical evidence for potato at Jiskairumoko in the Titicaca Basin of southern Peru

    Science.gov (United States)

    Rumold, Claudia Ursula

    2016-01-01

    The data presented in this paper provide direct microbotanical evidence concerning the early use of potato (Solanum tuberosum) within its botanical locus of origin in the high south-central Andes. The data derive from Jiskairumoko, an early village site in the western Titicaca Basin dating to the Late Archaic to Early Formative periods (∼3,400 cal y BC to 1,600 cal y BC). Because the site reflects the transition to sedentism and food production, these data may relate to potato domestication and early cultivation. Of 141 starch microremains recovered from 14 groundstone tools from Jiskairumoko, 50 are identified as consistent with cultivated or domesticated potato, based on reference to published materials and a study of wild and cultivated potato starch morphology. Along with macro- and microbotanical evidence for chenopod consumption and grinding tool data reflecting intensive use of this technology throughout site occupation, the microbotanical data reported here suggest the intensive exploitation, if not cultivation, of plant resources at Jiskairumoko. Elucidating the details of the trajectory of potato domestication is necessary for an overall understanding of the development of highland Andean agriculture, as this crop is central to the autochthonous agricultural suite. A paucity of direct botanical evidence, however, has hindered research efforts. The results of the modern and archaeological starch analyses presented here underscore the utility of this method in addressing questions related to the timing, mode, and context of potato origins. PMID:27849582

  7. Late Archaic-Early Formative period microbotanical evidence for potato at Jiskairumoko in the Titicaca Basin of southern Peru.

    Science.gov (United States)

    Rumold, Claudia Ursula; Aldenderfer, Mark S

    2016-11-29

    The data presented in this paper provide direct microbotanical evidence concerning the early use of potato (Solanum tuberosum) within its botanical locus of origin in the high south-central Andes. The data derive from Jiskairumoko, an early village site in the western Titicaca Basin dating to the Late Archaic to Early Formative periods (∼3,400 cal y BC to 1,600 cal y BC). Because the site reflects the transition to sedentism and food production, these data may relate to potato domestication and early cultivation. Of 141 starch microremains recovered from 14 groundstone tools from Jiskairumoko, 50 are identified as consistent with cultivated or domesticated potato, based on reference to published materials and a study of wild and cultivated potato starch morphology. Along with macro- and microbotanical evidence for chenopod consumption and grinding tool data reflecting intensive use of this technology throughout site occupation, the microbotanical data reported here suggest the intensive exploitation, if not cultivation, of plant resources at Jiskairumoko. Elucidating the details of the trajectory of potato domestication is necessary for an overall understanding of the development of highland Andean agriculture, as this crop is central to the autochthonous agricultural suite. A paucity of direct botanical evidence, however, has hindered research efforts. The results of the modern and archaeological starch analyses presented here underscore the utility of this method in addressing questions related to the timing, mode, and context of potato origins.

  8. Tectonic subsidence analyses of miogeoclinal strata from mesozoic marginal basin of Peru

    Energy Technology Data Exchange (ETDEWEB)

    Devlin, W.J.

    1988-01-01

    The Western Peruvian trough is composed of an eastern miogeoclinical facies of carbonate and clastic strata, and a western eugeoclinal facies consisting of a succession of volcanic and sedimentary rocks. In norther and central Peru, the miogeocline is located between a tectonic hinge adjacent to platformal facies of the Maranon geanticline on the east, and an outer marginal high bounded by the Cordillera Blanca fault and Tapacocha axis on the west. Miogeoclinal and platformal strata in southern Peru occur in a broad belt between Arequipa and Lago Titicaca. A marginal basin setting has been proposed for the Western Peruvian trough and the several kilometers of subsidence in the basin has been attributed to back-arc extension and crustal thinning. As a test of this model, quantitative tectonic subsidence curves were constructed from representative sections within miogeoclinar strata from four localities. Preliminary results indicate that the calculated curves have the same overall form as the age-depth curve for ocean floor, suggesting that subsidence was controlled by cooling and thermal contraction of heated lithosphere. The slopes of the curves are less than those for subsidence of oceanic lithosphere. However, they are in agreement with geologic evidence that the miogeocline accumulated on continental crust. Significant variations in the timing of onset, duration, and magnitude of subsidence are observed between sections from northern and southern Peru.

  9. Potential Predictability and Prediction Skill for Southern Peru Summertime Rainfall

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    WU, S.; Notaro, M.; Vavrus, S. J.; Mortensen, E.; Block, P. J.; Montgomery, R. J.; De Pierola, J. N.; Sanchez, C.

    2016-12-01

    The central Andes receive over 50% of annual climatological rainfall during the short period of January-March. This summertime rainfall exhibits strong interannual and decadal variability, including severe drought events that incur devastating societal impacts and cause agricultural communities and mining facilities to compete for limited water resources. An improved seasonal prediction skill of summertime rainfall would aid in water resource planning and allocation across the water-limited southern Peru. While various underlying mechanisms have been proposed by past studies for the drivers of interannual variability in summertime rainfall across southern Peru, such as the El Niño-Southern Oscillation (ENSO), Madden Julian Oscillation (MJO), and extratropical forcings, operational forecasts continue to be largely based on rudimentary ENSO-based indices, such as NINO3.4, justifying further exploration of predictive skill. In order to bridge this gap between the understanding of driving mechanisms and the operational forecast, we performed systematic studies on the predictability and prediction skill of southern Peru summertime rainfall by constructing statistical forecast models using best available weather station and reanalysis datasets. At first, by assuming the first two empirical orthogonal functions (EOFs) of summertime rainfall are predictable, the potential predictability skill was evaluated for southern Peru. Then, we constructed a simple regression model, based on the time series of tropical Pacific sea-surface temperatures (SSTs), and a more advanced Linear Inverse Model (LIM), based on the EOFs of tropical ocean SSTs and large-scale atmosphere variables from reanalysis. Our results show that the LIM model consistently outperforms the more rudimentary regression models on the forecast skill of domain averaged precipitation index and individual station indices. The improvement of forecast correlation skill ranges from 10% to over 200% for different

  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, Daniel M.; O'Neill, John P.; Foster, Mercedes S.; Mark, Todd; Dauphine, Nico; Franke, Irma 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. War and early state formation in the northern Titicaca Basin, Peru.

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    Stanish, Charles; Levine, Abigail

    2011-08-23

    Excavations at the site of Taraco in the northern Titicaca Basin of southern Peru indicate a 2,600-y sequence of human occupation beginning ca. 1100 B.C.E. Previous research has identified several political centers in the region in the latter part of the first millennium B.C.E. The two largest centers were Taraco, located near the northern lake edge, and Pukara, located 50 km to the northwest in the grassland pampas. Our data reveal that a high-status residential section of Taraco was burned in the first century A.D., after which economic activity in the area dramatically declined. Coincident with this massive fire at Taraco, Pukara adopted many of the characteristics of state societies and emerged as an expanding regional polity. We conclude that organized conflict, beginning approximately 500 B.C.E., is a significant factor in the evolution of the archaic state in the northern Titicaca Basin.

  13. Recently active contractile deformation in the forearc of southern Peru

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    Hall, S. R.; Farber, D.; Audin, L.; Finkel, R. C.

    2010-12-01

    In the Precordillera and Western Cordillera of southern Peru (14°-18°S), vast pediment surfaces have been abandoned through drainage diversion and river incision, with the major drainages carving deep canyons. Within this region, we have identified range-sub-parallel contractile structures that accommodate significant distributed crustal deformation. Young geomorphic features document both the presence and youthfulness of these contractile structures. Here, we determine exposure ages on geomorphic features such as pediment surfaces and fluvial terraces using in situ produced cosmogenic radionuclides, in conjunction with field and remote mapping. This chronologic data reveals that ancient surfaces have been preserved as a result of very low erosion rates. We measure this rate to be chronology and geomorphic mapping, we calculate a Pleistocene river incision rate of ~0.3mm/yr determined from data collected along exoreic rivers. This rate is consistent with longer-term incision rates measured in other localities along this margin. We suggest that, in this region of southern Peru, the steep western wedge of the Andean margin supports the high topography of the Altiplano through a combination of uplift along steeply dipping contractile west-vergent structures and isostatic responses to the focused removal of large amounts of crustal material through canyon incision. Further, that these range sub-parallel structures are related at depth to a thrust system that plays a role in not only the maintenance of the Andean margin, but potentially in its formation as well.

  14. Mortality in children among the Aymara Indians of southern Peru.

    Science.gov (United States)

    de Meer, K

    1988-01-01

    During the fieldwork on illness in children in an Aymara peasant community in Southern Peru, data was collected on child mortality. In 35 families surveyed in the village, the total child mortality rate was estimated diachronically at 380 per 1,000 live births. The majority of the child death in these families occurred in the first days after birth. These deaths were also counted as perinatal deaths, and thus the perinatal mortality rate was found to be high as well at 252 per 1,000 total births (99% confidence interval: 181-330 per 1,000). Congenital malformations incompatible with life, neonatal tetanus, and other neonatal disorders did not have an especially high frequency in the village. These disorders seem to explain only a part of the early neonatal deaths responsible for the high mortality rates in children. As perinatal deaths were concentrated in 13 of the 35 families in the survey (especially in those families with many total births and at least two living children), the possibility of infanticide was put forward to explain the high death rates in children in the first days of life. This hypothesis was supported by practices in the village concerning the baptism of dead children by which the cause of death was left unsanctioned. Infanticide could be important to curb recent and future population growth and the resulting pressure on the land.

  15. Mineralogy of the Chaparra IOCG deposit, southern Peru

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    Yáñez, Juan; Alfonso, Pura

    2014-05-01

    The Chaparra IOCG, located in southern Peru, near Chala, is mined and exploited by small-scale miners for gold, however, it has not been studied until now. Here we present a preliminary geological and mineralogic study of this deposit. Powder X ray diffraction, electron microscopy and electron microprobe were used to characterize the mineralization. This deposit is hosted in magmatic rocks from the Coastal Batholith. Host rocks belong to the Linga Super-unit, of Upper Cretaceous age and are mainly constituted by monzonites, monzogabbros and diorites. Major alterations are the propylitic (chlorite - albite - quartz), advanced argillic (jarosite - natrojarosite) and sericitic (muscovite-sericite-quartz). Gypsum and other alteration minerals such as potassium feldspar and phlogopite, vermiculite and natrolite are widespread. Mineralization occurs mainly in quartz veins up to 1 m thick, emplaced filling fractures. Ore mineralogy is mainly composed of hematite, goethite, and sulphides (mainly pyrite, chalcopyrite and covellite). Gold and REE-rich minerals also occur. Native gold can reach up to 1 mm in size, but usually is few μm in size. Its composition is 82-92 wt% Au, up to 12 wt% of Ag and Fe can reach up to 4 wt%. The paragenetic sequence in the Chaparra deposit was divided into three stages: (I) primary mineralization, (II) Fracture filling, and (III) supergene alteration. The sequence begins with the crystallization of magnetite, quartz, pyrrhotite and pyrite. Subsequently, native gold, native Bismuth and uraninite crystallices together with the former minerals, in which are enclosed. Later, monacite is formed, being enclosed in quartz. Pyrite also presents small grains of chalcopyrite inside. Galena, sphalerite and arsenopyrite also are formed, whether included in pyrite or outside. Scarce grains of sakuraiite also occur in this stage. Structural formula of sakuraiie from this deposit is Cu 01.78-1.90 Zn 0.07-12Fe 1.16-124In 0.22-0.26Sn 0.79-082S4). Indium

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

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    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.

  17. Ground failure in the 2001 Mw 8.4 southern Peru earthquake

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    Rondinel-Oviedo, Efrain Alejandro

    On June 23rd 2001 a moment magnitude (M W) 8.4, earthquake shook the southern portion of Peru. This rare large-magnitude event provided a unique opportunity to develop a suite of high quality case histories and also to test and calibrate existing geotechnical earthquake engineering analysis procedures and models against observations from the earthquake. The work presented in this thesis is focused on three topics pertaining to ground failure (i.e., the permanent deformation of the ground resulting from an earthquake) observed during the event: (1) surface ground damage in small basin geometries, (2) seismic compression, and (3) performance of a concrete faced rockfill dam (CFRD) dam. Surface ground strain damage patterns in small basin geometries has previously been typically studied at the large (i.e., geological) scale, but not at the scale of civil engineering infrastructure. During seismic events basin geometries containing soft material confined by stiffer material trap the seismic waves and generate surface waves that travel on the ground along the soft material. Numerical modeling shows that surface waves are generated at basin edges and travel on the ground creating higher duration, higher response (peak ground acceleration, PGA), higher energy (Arias Intensity) and higher angular distortion, especially in zones close to the edges. The impedance contrast between the stiff material and the soft material, and the dip angle play an important role in basin response. Seismic compression (i.e., the shaking induced densification of unsaturated soil) was observed in many highway embankments in the region of the earthquake. In many instances, this phenomenon was exasperated by soil-structure interaction with adjacent bridge or culvert structures. Numerical modeling conducted as part of this research showed (i) a significantly different response when the structure (culvert) is considered, (ii) impedance contrast plays a role in the system responses, and (iii) low

  18. 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.

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

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    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. 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)

  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. Holocene lake-level fluctuations of Lake Aricota, Southern Peru

    Science.gov (United States)

    Placzek, C.; Quade, Jay; Betancourt, J.L.

    2001-01-01

    Lacustrine deposits exposed around Lake Aricota, Peru (17?? 22???S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (Titicaca (16?? S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes. ?? 2001 University of Washington.

  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.

  4. 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.

  5. Late Paleozoic to Jurassic chronostratigraphy of coastal southern Peru: Temporal evolution of sedimentation along an active margin

    Science.gov (United States)

    Boekhout, F.; Sempere, T.; Spikings, R.; Schaltegger, U.

    2013-11-01

    We present an integrated geochronological and sedimentological study that significantly revises the basin and magmatic history associated with lithospheric thinning in southern coastal Peru (15-18°S) since the onset of subduction at ˜530 Ma. Until now, estimating the age of the sedimentary and volcanic rocks has heavily relied on paleontologic determinations. Our new geochronological data, combined with numerous field observations, provide the first robust constraints on their chronostratigraphy, which is discussed in the light of biostratigraphical attributions. A detailed review of the existing local units simplifies the current stratigraphic nomenclature and clarifies its absolute chronology using zircon U-Pb ages. We observe that the Late Paleozoic to Jurassic stratigraphy of coastal southern Peru consists of two first-order units, namely (1) the Yamayo Group, a sedimentary succession of variable (0-2 km) thickness, with apparently no nearby volcanic lateral equivalent, and (2) the overlying Yura Group, consisting of a lower, 1-6 km-thick volcanic and volcaniclastic unit, the Chocolate Formation, and an upper, 1-2 km-thick sedimentary succession that are in markedly diachronous contact across the coeval arc and back-arc. We date the local base of the Chocolate Formation, and thus of the Yura Group, to 216 Ma, and show that the underlying Yamayo Group spans a >110 Myr-long time interval, from at least the Late Visean to the Late Triassic, and is apparently devoid of significant internal discontinuities. The age of the top of the Chocolate Formation, i.e. of the volcanic arc pile, varies from ˜194 Ma to less than ˜135 Ma across the study area. We suggest that this simplified and updated stratigraphic framework can be reliably used as a reference for future studies.

  6. Holocene Lake-Level Fluctuations of Lake Aricota, Southern Peru

    Science.gov (United States)

    Placzek, Christa; Quade, Jay; Betancourt, Julio L.

    2001-09-01

    Lacustrine deposits exposed around Lake Aricota, Peru (17° 22‧S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (<350 yr). Diatomites associated with highstands several meters above the modern lake level indicate wet episodes. Maximum Holocene lake level was attained before 6100 14C yr B.P. and ended ∼2700 14C yr B.P. Moderately high lake levels occurred at 1700 and 1300 14C yr B.P. The highstand at Lake Aricota during the middle Holocene is coeval with a major lowstand at Lake Titicaca (16°S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes.

  7. 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.

  8. Assessment of Aero-radiometric Data of Southern Anambra Basin ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Potassium and Thorium) were used and processed independently to investigate the Southern. Anambra basin for the .... Based on the Rybach equation (1) above, Uranium produces the .... Geothermal Exploration: State of the Art. Techniques.

  9. On the origin of the southern Permian Basin, Central Europe.

    NARCIS (Netherlands)

    van Wees, J.D.A.M.; Stephenson, R.A.; Ziegler, P.A.; Bayer, U.; McCann, T.; Dadlez, R.; Gaupp, R.; Narkiewicz, M.; Bitzer, F.; Scheck, M.

    2000-01-01

    A detailed study of the structural and stratigraphic evolution of the Southern Permian Basin during latest Carboniferous to Early Jurassic times, supported by quantitative subsidence analyses and forward basin modelling for 25 wells, leads us to modify the conventional model for the

  10. Early maize agriculture and interzonal interaction in southern Peru.

    Science.gov (United States)

    Perry, Linda; Sandweiss, Daniel H; Piperno, Dolores R; Rademaker, Kurt; Malpass, Michael A; Umire, Adán; de la Vera, Pablo

    2006-03-02

    Over the past decade, increasing attention to the recovery and identification of plant microfossil remains from archaeological sites located in lowland South America has significantly increased knowledge of pre-Columbian plant domestication and crop plant dispersals in tropical forests and other regions. Along the Andean mountain chain, however, the chronology and trajectory of plant domestication are still poorly understood for both important indigenous staple crops such as the potato (Solanum sp.) and others exogenous to the region, for example, maize (Zea mays). Here we report the analyses of plant microremains from a late preceramic house (3,431 +/- 45 to 3,745 +/- 65 14C bp or approximately 3,600 to 4,000 calibrated years bp) in the highland southern Peruvian site of Waynuna. Our results extend the record of maize by at least a millennium in the southern Andes, show on-site processing of maize into flour, provide direct evidence for the deliberate movement of plant foods by humans from the tropical forest to the highlands, and confirm the potential of plant microfossil analysis in understanding ancient plant use and migration in this region.

  11. [Fertility and reproductive behavior in Peru: Andes mountains and the Amazon basin].

    Science.gov (United States)

    Fort, A L

    1992-01-01

    "The article attempts to discuss the historical and contemporary situations of [fertility among] populations residing in the two least studied areas of Peru: the Andes mountains and the Amazon basin. The study starts with a review of the 'demographic catastrophe' that the Spanish presence meant to the people of these areas.... The harmful effects of the 'rubber boom' and, more recently, of the 'oil boom', periods are also reviewed." Fertility trends in the two areas are analyzed, with a focus on marriage, breast-feeding, and contraceptive use. (SUMMARY IN ENG) excerpt

  12. 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

  13. Environmental records from temperate glacier ice on Nevado Coropuna saddle, southern Peru

    Directory of Open Access Journals (Sweden)

    J. Herreros

    2009-10-01

    Full Text Available We investigated past climate variability and the zonal short and long-range transport of air masses in tropical South America using chemical, isotopic and palynological signals from a 42 m-long ice core recovered in 2003 from the saddle of the Nevado Coropuna, southern Peru (72°39´ W; 15°32´ S; 6080 m a.s.l.. We found that precipitation at this site depends mainly on the easterly circulation of air masses originated from the tropical Atlantic Ocean. Nevertheless, sporadic Pacific air masses arrivals, and strong cold waves coming from southern South America reach this altitude site. In spite of post-depositional effects, we were able to identify two strong ENSO (El Niño-Southern Oscillation event signatures (1982–1983 and 1992 and the eruptive activity of the nearby Sabancaya volcano (1994.

  14. Paleozoic evolution of active margin basins in the southern Central Andes (northwestern Argentina and northern Chile)

    Science.gov (United States)

    Bahlburg, H.; Breitkreuz, C.

    originated as an extensional structure at the continental margin of Gondwana. Independent lines of evidence imply that basin evolution was not connected to subduction. Thus, the basin could not have been in a fore-arc position as previously postulated. Above the folded Devonian-Early Carboniferous strata, a continental volcanic arc developed from the Late Carboniferous to the Middle Triassic. It represents the link between the Choiyoi Province in central Chile and Argentina, and the Mitu Group rift in southern Peru. The volcanic arc succession is characterized by the prevalence of silicic lavas and tuffs and volcaniclastic sedimentary rocks. During the latest Carboniferous, a thick ostracod-bearing lacustrine unit formed in an extended lake in the area of the Depresión Preandina. This lake basin originated in an intra-arc tensional setting. During the Early Permian, marine limestones were deposited on a marine platform west and east of the volcanic arc, connected to the depositional area of the Copacabana Formation in southern Peru.

  15. A case of partial xanthism in a marblefish Aplodactylus punctatus (Teleostei: Aplodactylidae) from southern Peru

    OpenAIRE

    Béarez, Philippe; Treviño, Hugo Treviño; Huamani, Isaac

    2006-01-01

    Se reporta por primera vez en Ilo, sur del Perú, una jerguilla amarilla (Aplodactylus punctatus). Esa condición de tener una piel de color amarillo se denomina xantismo. Este registro, único, corresponde probablemente a una extensión hacia el norte del rango de distribución de la «jerguilla reina», conocida de la costa central de Chile. A yellow skinned jerguilla (Aplodactylus punctatus) is reported for the first time from Ilo, Southern Peru. This condition of skin, in which yellow colorat...

  16. Seismic attenuation structure beneath Nazca Plate subduction zone in southern Peru

    Science.gov (United States)

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

    2017-12-01

    We estimate seismic attenuation in terms of quality factors, QP and QS using P and S phases, respectively, beneath Nazca Plate subduction zone between 10°S and 18.5°S latitude in southern Peru. We first relocate 298 earthquakes with magnitude ranges of 4.0-6.5 and depth ranges of 20-280 km. We measure t*, which is an integrated attenuation through the seismic raypath between the regional earthquakes and stations. The measured t* are inverted to construct three-dimensional attenuation structures of southern Peru. Checkerboard test results for both QP and QS structures ensure good resolution in the slab-dip transition zone between flat and normal slab subduction down to a depth of 200 km. Both QP and QS results show higher attenuation continued down to a depth of 50 km beneath volcanic arc and also beneath the Quimsachata volcano, the northernmost young volcano, located far east of the main volcanic front. We also observe high attenuation in mantle wedge especially beneath the normal subduction region in both QP and QS (100-130 in QP and 100-125 in QS) and slightly higher QP and QS beneath the flat-subduction and slab-dip transition regions. We plan to relate measured attenuation in the mantle wedge to material properties such as viscosity to understand the subduction zone dynamics.

  17. 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.

    2013-01-01

    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. PMID:23243107

  18. 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

  19. Amphitheca isaacsonii gen. et sp. nov. (Acritarcha) from the Ananea Formation (Silurian/Devonian transition), southern Peru

    Czech Academy of Sciences Publication Activity Database

    Vavrdová, Milada; Svobodová, Marcela

    2010-01-01

    Roč. 179, - (2010), s. 189-196 ISSN 1802-6842 Institutional research plan: CEZ:AV0Z30130516 Keywords : Ananea Formation * Amphitheca gen. nov. * acritarchs * southern Peru Subject RIV: DB - Geology ; Mineralogy http://www.nm.cz/publikace/publikace-download.php?name=File1&dir=archiv&table=tabPublikaceArchiv&id=2795

  20. 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.

  1. The Jurassic-early Cretaceous Ilo batholith of southern coastal Peru: geology, geochronology and geochemistry

    Science.gov (United States)

    Boekhout, Flora; Sempere, Thierry; Spikings, Richard; Schaltegger, Urs

    2010-05-01

    The Ilo batholith (17°00 - 18°30 S) crops out in an area of about 20 by 100 km, along the coast of southern Peru. This batholith is emplaced into the ‘Chocolate‘ Formation of late Permian to middle Jurassic age, which consists of more than 1000 m of basaltic and andesitic lavas, with interbedded volcanic agglomerates and breccias. The Ilo Batholith is considered to be a rarely exposed fragment of the Jurassic arc in Peru. Our aim is to reconstruct the magmatic evolution of this batholith, and place it within the context of long-lasting magma genesis along the active Andean margin since the Paleozoic. Sampling for dating and geochemical analyses was carried out along several cross sections through the batholith that were exposed by post-intrusion eastward tilting of 20-30°. Sparse previous work postulates early to middle Jurassic and partially early Cretaceous emplacement, on the basis of conventional K/Ar and 40Ar/39Ar dating methods in the Ilo area. Twenty new U-Pb zircon ages (LA-ICP-MS and CA-ID-TIMS) accompanied by geochemical data suggests the Ilo batholith formed via the amalgamation of middle Jurassic and early Cretaceous, subduction-related plutons. Preliminary Hf isotope studies reveal a primitive mantle source for middle Jurassic intrusions. Additional Sr, Nd and Hf isotope analyses are planned to further resolve the source regions of different pulses of plutonic activity. We strongly suggest that batholith emplacement was at least partly coeval with the emplacement of the late Permian to middle Jurassic Chocolate Formation, which was deposited in an extensional tectonic regime. Our age results and geochemical signature fit into the scheme of episodic emplacement of huge amounts of subduction related magmatism that is observed throughout the whole Andean event, particularly during the middle Jurassic onset of the first Andean cycle (southern Peru, northern Chile and southern Argentina). Although the exact geodynamic setting remains to be precisely

  2. Assessment of Aero-radiometric Data of Southern Anambra Basin ...

    African Journals Online (AJOL)

    High-resolution aero-radiometric data from three radio-elements (Uranium, Potassium and Thorium) were used and processed independently to investigate the Southern Anambra basin for the prospect of producing radiogenic heat. The rock types in the study area were outlined while processing the elements in each rock ...

  3. Hydrogeophysical investigation of Southern Anambra Basin Nigeria ...

    African Journals Online (AJOL)

    The analytical relationship between the Dar Zarrouk parameters and the hydraulic characteristics were used to assess the hydrogeological condition of the basin. These have led to inferences about the aquifer hydraulic conductivities and transmissivities and K product across the area. Consequently favourable areas have ...

  4. Socio-cultural determinants of child mortality in southern Peru: including some methodological considerations.

    Science.gov (United States)

    de Meer, K; Bergman, R; Kusner, J S

    1993-02-01

    Among Amerindian children living at high altitude in the Andes in southern Peru, high child mortality rates have been reported in the literature, especially in the perinatal and neonatal period. We compared mortality rates in children calculated from retrospective survey data in 86 rural families from 2 Aymara and 3 Quechua peasant communities living at the same level of altitude (3825 m) in southern Peru. Relations between land tenure, socio-cultural factors and child mortality were studied, and methodological considerations in this field of interest are discussed. Checks on consistency of empirical data showed evidence for underreporting of neonatal female deaths with birth order 3 and more. Perinatal (124 vs 34 per 1000 births) and infant mortality (223 vs 111 per 1000 live births) was significantly higher in Aymara compared with Quechua children, but no difference was found after the first year of life. A short pregnancy interval was associated with an elevated perinatal and infant mortality rate, and a similar albeit insignificant association was found with increased maternal age. Amount of land owned and birth order were not related with child mortality. Although levels of maternal education are generally low in both cultures, a consistent decline in infant and child mortality was found with the amount of years mothers had attended school. However, the results suggest a U-shaped relationship between the amount of years of parental education and perinatal mortality in offspring. Late fetal and early neonatal mortality were particularly high in one Aymara community where mothers were found to have more years of education. Infanticide, a known phenomenon in the highlands of the Andes, is discussed in relation with the findings of the study. Although maternal and child health services are utilized by the majority of families in 4 of 5 study communities, 43 of 51 mothers under the age of 45 years reported that they delivered their last baby in the absence of

  5. 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

  6. Compositional changes of surface sediments and variability of manganese nodules in the Peru Basin

    Science.gov (United States)

    Marchig, Vesna; von Stackelberg, Ulrich; Hufnagel, Heinz; Durn, Goran

    Two types of manganese nodules were observed in the Peru Basin: large botryoidal nodules in basins and small ellipsoidal nodules on slope positions. The sediment in areas with large botryoidal nodules contains a thinner and weaker oxidation zone than the sediment under small ellipsoidal nodules, indicating that diagenetic processes in the sediment, which supply manganese nodules with metals for their growth, are stronger in sediments on which large botryoidal nodules grow. Organic matter, which activates remobilization of metals, occurs mostly in the form of refractory lipidic compounds in the inner capsule of radiolaria. This material needs bacterial degradation to act as a reducing agent. Easily oxidizable organic components could not be found in the sediments. Other changes in sediment composition do not have a link to manganese nodule growth. Biogenous components (radiolarians, organogenic barite and apatite) increase towards the equatorial high-productivity zone. Authigenous clay minerals (nontronite as well as montmorillonite with high Fe +3 incorporation on positions of ochtaedral Al) increase with distance from the continent. The assessment of environmental impacts will have to take into account the regional differences in sediment composition and the small-scale variability of manganese nodules.

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

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    James Anyelo Vanegas-Ríos

    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.

  8. Timing of deformation and rapid subsidence in the northern Altiplano, Peru: Insights from detrital zircon geochronology of the Ayaviri hinterland basin

    Science.gov (United States)

    Horton, B. K.; Perez, N. D.; Saylor, J. E.

    2011-12-01

    Although age constraints on crustal deformation and sediment accumulation prove critical to testing hypotheses of orogenic plateau construction, a common lack of marine facies, volcanic tuffs, and suitable fossils hinders many attempts at chronological reconstructions. A series of elevated retroarc basins along the axis of the Andean orogenic belt provide opportunities to define the timing of deformation and transformation from foreland to hinterland basin configurations. In this study, we present new U-Pb ages of detrital zircons in the Ayaviri intermontane basin of southern Peru (~4 km elevation) in the northern part of the central Andean (Altiplano) plateau. Nearly all sandstone samples show strong unimodal U-Pb age peaks (generally defined by > 5-50 zircons), suggesting these age peaks represent syndepositional volcanism and can be regarded as accurate estimates of true depositional (stratigraphic) age. Integration of these ages with structural and stratigraphic relationships demonstrate the utility of zircon U-Pb geochronology in defining both (1) the timing of basin partitioning and (2) the pace of sediment accumulation. (1) U-Pb ages for several sandstone samples from growth-strata packages associated with two basin-bounding faults reveal structural partitioning of the Ayaviri basin from late Oligocene to Miocene time. In the north, displacement along the southwest-directed Ayaviri thrust fault commenced in late Oligocene time (~28-24 Ma), inducing initial structural partitioning of an upper Eocene-Oligocene, > 5 km thick succession potentially representing an early Andean retroarc foreland basin. In the south, the Ayaviri basin was further disrupted by initial displacement along the northeast-directed Pasani thrust fault in early to middle Miocene time (~18-15 Ma). (2) Additional U-Pb analyses from the Ayaviri basin fill help delimit the long-term rates of sedimentation, suggesting relatively short-lived (< 5 Myr) pulses of accelerated accumulation. Rapid

  9. Southern Peru desert shattered by the great 2001 earthquake: Implications for paleoseismic and paleo-El Niño–Southern Oscillation records

    OpenAIRE

    Keefer, David K.; Moseley, Michael E.

    2004-01-01

    In the desert region around the coastal city of Ilo, the great southern Peru earthquake of June 23, 2001 (8.2–8.4 moment magnitude), produced intense and widespread ground-failure effects. These effects included abundant landslides, pervasive ground cracking, microfracturing of surficial hillslope materials, collapse of drainage banks over long stretches, widening of hillside rills, and lengthening of first-order tributary channels. We have coined the term “shattered landscape” to describe th...

  10. Geomorphic Effects, Chronologies, and Archaeological Significance of El Nino Floods in Southern Peru

    Science.gov (United States)

    Magilligan, F. J.; Manners, R.; Goldstein, P.

    2003-12-01

    The catastrophic effects of large floods have been well documented, on both contemporary and paleo-timecales, especially for the conterminous U.S. Less is known, however, about extreme events in hyper-arid sub-tropical climates where synoptic scale meteorological causes, such as El Nino-Southern Oscillation events, are the driving atmospheric mechanism. This research documents the geomorphic effects of extreme floods in the Moquegua River valley of southern Peru, in the core of the Atacama Desert. Using a combination of geomorphic mapping, hydrolologic modeling, aerial photography, ASTER satellite imagery, and GIS, we document the geomorphic signature of large contemporary floods within the mid-valley section (1500 masl) of the Rio Moquegua. Stratigraphic evidence and paleostage indicators of paleofloods, such as slackwater deposits and preserved high level flood gravels, are used to evidence late Holocene paleoflood magnitude-frequency relationships. On contemporary timescales, channel belt expansion by lateral erosion during large floods, such as the recent '97 and '98 floods, correspond to as much as 30-40 hectares of floodplain loss along the 20 km study reach. Sixty years of repeat aerial photography indicates that channel belt expansion and floodplain erosion commonly occurs along the Rio Moquegua. The frequent resetting of floodplain alluvium conditioned by these large floods is supported by radiocarbon dating of floodplain exposures. These dates indicate that most of the contemporary floodplain alluvium is younger that 560 14C yrs BP. The highest terrace remnants date to 3250 14C yrs BP and record a series of overbank flood gravels. Evidence for the regionally extensive Miraflores ENSO flood, ca. 1300 AD, exists in tributary and along mainstem sections. This flood has been documented along the coasts of Northern Chile to northern Peru, and has been evoked to explain significant social collapse. Our field evidence indicates that it catastrophically affected

  11. Growth of a manganese nodule from Peru Basin: a radiochemical anatomy

    International Nuclear Information System (INIS)

    Reyss, J.L.; Lemaitre, N.; Marchig, V.; Southon, J.R.; Nelson, D.E.; Vogel, J.S.

    1985-01-01

    Attempts have been made to study the entire growth history of a manganese nodule from the northern part of Peru Basin in the Pacific using radiochemical profiles of 230 Th/ 232 Th, 227 Th/ 230 Th and 10 Be/ 9 Be. Combined with the observations on Fe-Mn contents and textural variation, the radiochemical data indicate that the nodule grew more or less concentrically throughout most of its existence since it formed 1.5 my ago, receiving Mn from both bottom water and pore water. This condition appeared to have changed about 180 ky ago when the growth became asymmetric in that the top and bottom sides became fixed in their relative positions on the sea floor. Since then, the bottom side accreted with a fast rate of close to 200 mm/my, apparently fueled by the supply of diagenetically remobilized Mn in pore water from the sediment substrate. In the meantime, the topside accumulated at about 6 mm/my, a value which is in the normal range for deep-sea nodules having their Mn supplied from the hydrogenous source. (author)

  12. A change in landscape: Lessons learned from abandonment of ancient Wari agricultural terraces in Southern Peru.

    Science.gov (United States)

    Londoño, Ana C; Williams, Patrick Ryan; Hart, Megan L

    2017-11-01

    Ancient agricultural terrace practices have survived for millennia, sustaining populations through extreme climatic shifts and political regime changes. In arid regions with abrupt relief such as Southern Peru, agricultural terracing is undergoing a resurgence, as has seen revitalization of once abandoned terrace and hydraulic systems. Wari terraces at Cerro Baul provide clues to past cultural practices. They also document sustainable farming practices by using resilient land management techniques which can help combat desertification and degradation of arable lands. Three abandoned Wari terrace systems were mapped using microtopographic methods, the erosion patterns examined, the states of preservation compared, and then the design contrasted with modern terracing practices in the Moquegua Valley. In order to negate the harmful effects of desertification, rehabilitation and reconstruction of these terraces using ancient knowledge and techniques may be necessary. Rehabilitation must be conducted with consideration for preservation of cultural patrimony that may be encountered within the terrace treads or riser structures. With future climatic shifts impacting vulnerable dryland areas more than others, the ability to resiliently respond to these changes may be found in the lessons learned from ancient farming techniques such as the Wari. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Structure of the subduction system in southern Peru from seismic array data

    Science.gov (United States)

    Phillips, Kristin; Clayton, Robert W.; Davis, Paul; Tavera, Hernando; Guy, Richard; Skinner, Steven; Stubailo, Igor; Audin, Laurence; Aguilar, Victor

    2012-11-01

    The subduction zone in southern Peru is imaged using converted phases from teleseismic P, PP, and PKP waves and Pwave tomography using local and teleseismic events with a linear array of 50 broadband seismic stations spanning 300 km from the coast to near Lake Titicaca. The slab dips at 30° and can be observed to a depth of over 200 km. The Moho is seen as a continuous interface along the profile, and the crustal thickness in the back-arc region (the Altiplano) is 75 km thick, which is sufficient to isostatically support the Andes, as evidenced by the gravity. The shallow crust has zones of negative impedance at a depth of 20 km, which is likely the result of volcanism. At the midcrustal level of 40 km, there is a continuous structure with a positive impedance contrast, which we interpret as the western extent of the Brazilian Craton as it underthrusts to the west.Vp/Vs ratios estimated from receiver function stacks show average values for this region with a few areas of elevated Vp/Vs near the volcanic arc and at a few points in the Altiplano. The results support a model of crustal thickening in which the margin crust is underthrust by the Brazilian Shield.

  14. Elevational Shifts in the Topographic Position of Polylepis Forest Stands in the Andes of Southern Peru

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    Johanna M. Toivonen

    2017-12-01

    Full Text Available The patchy distribution of high-Andean treeline forests has provoked discussion about the relative importance of anthropogenic and climatic causes of this pattern, both of which vary with topography. We aimed to understand the topographic controls on the distribution of Polylepis subsericans treeline forests in the Andes of southern Peru, and the changes in these controls along an elevational gradient. We mapped Polylepis forests in the Cordillera Urubamba, Cusco, using high-resolution aerial images and related forest cover to topographic variables extracted from a digital terrain model (30-m resolution. The variables were selected based on their expected biological relevance for tree growth at high elevations. We constructed logistic regression models of forest cover, separately for each of five 100-m elevational belts. To deal with spatial autocorrelation, models were based on randomized 10% subsampling of the data with 1000 repetitions. The results suggest a consistent shift in topographic preference with elevation, with forests at lower elevations showing a preference for topographically protected sites near rivers and forests at higher elevations being increasingly restricted to north-facing and well-drained sites. Our study offers the first indication of the ability of Andean treeline forests to benefit from the topographic heterogeneity of the high-Andes. Providing that dispersal and establishment are possible, local relocation between microsites could help these forests to persist regionally in spite of changing climatic conditions.

  15. Precise chronologies of Holocene glacial culminations in the Cordillera Vilcabamba of southern Peru

    Science.gov (United States)

    Licciardi, J. M.; Schaefer, J. M.; Schweinsberg, A. D.

    2012-12-01

    Records of past fluctuations in climatically sensitive tropical mountain glaciers are among the best indicators of regional paleoclimatic trends and controls. The majority of the world's present-day tropical glaciers are found in the Peruvian Andes, but accurate and precise chronologies of past glacial activity in this region remain relatively scarce, particularly during the Holocene. Here we present ~50 new 10Be exposure ages derived from boulders on well-preserved moraine successions in several glaciated drainages in the Cordillera Vilcabamba of southern Peru (13°20'S latitude). The new results suggest that prominent moraines in these valleys are correlative with previously published moraine ages near Nevado Salcantay in this range (Licciardi et al., 2009), but also expand on the initial surface exposure chronologies to reveal additional periods of glacier stabilization not found in previous work. A provisional composite chronology that merges the new and previously obtained moraine ages indicates at least five discrete glacial culminations from the Lateglacial to the late Holocene. Forthcoming 10Be ages from an additional ~50 samples collected from moraine boulders will increase the precision and completeness of the Vilcabamba moraine chronologies. Basal radiocarbon ages are being developed from bog and lake sediments in stratigraphic contact with the 10Be-dated moraines. These new 14C age data will help constrain the local cosmogenic 10Be production rate, thereby increasing the accuracy of the 10Be chronologies.

  16. 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

  17. Tertiary stratigraphy and basin evolution, southern Sabah (Malaysian Borneo)

    Science.gov (United States)

    Balaguru, Allagu; Nichols, Gary

    2004-08-01

    New mapping and dating of strata in the southern part of the Central Sabah Basin in northern Borneo has made it possible to revise the lithostratigraphy and chronostratigraphy of the area. The recognition in the field of an Early Miocene regional unconformity, which may be equivalent to the Deep Regional Unconformity recognised offshore, has allowed the development of a stratigraphic framework of groups and formations, which correspond to stages in the sedimentary basin development of the area. Below the Early Miocene unconformity lies ophiolitic basement, which is overlain by an accretionary complex of Eocene age and a late Paleogene deep water succession which formed in a fore-arc basin. The late Paleogene deposits underwent syn-depositional deformation, including the development of extensive melanges, all of which can be demonstrated to lie below the unconformity in this area. Some localised limestone deposition occurred during a period of uplift and erosion in the Early Miocene, following which there was an influx of clastic sediments deposited in delta and pro-deltaic environments in the Middle Miocene. These deltaic to shallow marine deposits are now recognised as forming two coarsening-upward successions, mapped as the Tanjong and Kapilit Formations. The total thickness of these two formations in the Central Sabah Basin amounts to 6000 m, only half of the previous estimates, although the total stratigraphic thickness of Cenozoic clastic strata in Sabah may be more than 20,000 m.

  18. 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

  19. Fishes of the Taquari-Antas river basin (Patos Lagoon basin, southern Brazil

    Directory of Open Access Journals (Sweden)

    FG. Becker

    Full Text Available The aquatic habitats of the Taquari-Antas river basin (in the Patos Lagoon basin, southern Brazil are under marked environmental transformation because of river damming for hydropower production. In order to provide an information baseline on the fish fauna of the Taquari-Antas basin, we provide a comprehensive survey of fish species based on primary and secondary data. We found 5,299 valid records of fish species in the basin, representing 119 species and 519 sampling sites. There are 13 non-native species, six of which are native to other Neotropical river basins. About 24% of the total native species are still lacking a taxonomic description at the species level. Three native long-distance migratory species were recorded (Leporinus obtusidens, Prochilodus lineatus, Salminus brasiliensis, as well as two potential mid-distance migrators (Parapimelodus nigribarbis and Pimelodus pintado. Although there is only one officially endangered species in the basin (S. brasiliensis, restricted range species (21.7% of total species should be considered in conservation efforts.

  20. A Geochemical Comparison of the Northern Peninsular Ranges Batholith in Southern California and the Coastal Batholith in Southern Peru

    Science.gov (United States)

    Clausen, B. L.; Martínez Ardila, A. M.; Morton, D. M.

    2010-12-01

    An extensive geochemical data set from the northern Peninsular Ranges Batholith (PRB) in southern California is compared and contrasted with the Arequipa segment of the Peruvian Coastal Batholith, including new granitoid samples recently collected near Ica (14°S, 76°W). The data include major and trace elements and Sr isotope ratios. This is part of an on-going study of subduction-related magmatism to refine a petrogenetic model of crust formation at plate boundaries, with a particular interest in the role of magma mixing. Research in the northern PRB suggests that continental crust is formed in several cycles: (1) mantle melting to give mafic volcanics and gabbroic intrusives, (2) basalt/gabbro melting to give felsic granitoids uncontaminated by continental crust and having low initial 87Sr/86Sr (Sri) values less than 0.704, and (3) crustal melting to give high Sri values greater than 0.704. Geochemical evidence was used to determine the extent of mixing between mafic and felsic magma that produced rocks of intermediate SiO2 composition. These differentiation cycles formed a west to east chronologic sequence and yielded granitoids of gabbro, tonalite, and granodiorite composition. Using principal component analysis on the northern PRB granitoids, the four factors affecting geochemical composition were categorized as differentiation, crustal contamination, depth of magma source, and conditions that yield a range from calcic to more alkaline granitoids. A similar major and trace element analysis is being done for a classic result of subduction in the Peruvian Coastal Batholith. The Peruvian samples recently collected include granitoids of the upper Cretaceous Coastal Batholith, as well as the associated volcanics of Cretaceous and Jurassic age. The Coastal Batholith samples include a range of granitoids from the early gabbros and from the four batholithic super-units (from west to east: Linga, Pampahuasi, Tiabaya, and Incahuasi) containing a combination of diorite

  1. Oxygen Isotope Compositions of Meteoric Water Across an Elevation Gradient in Southern Peru

    Science.gov (United States)

    Xu, D. R.; White, E.; Cassel, E. J.; Lynch, B.; Yanites, B.; Breecker, D.

    2017-12-01

    The Central Andes is a prime example of elevated topography generated by oceanic plate subduction. Whereas previous stable isotope studies have investigated the paleoelevation of the Andean Eastern Cordillera, little is known about the paleoelevation of the Western Cordillera, where arc volcanism now occurs. As a first step towards studying the paleoelevation of this region, we investigated the change in δ18O values of modern soil waters across an elevation gradient from sea level to about 4725 meters in southern Peru. We sampled soil profiles from 5 to 80 cm in 15-20cm increments, and we sampled water from flowing natural streams at various elevations. We used cryogenic vacuum extraction to quantitatively remove non-structural water from soil samples. The δ18O values of water extracted from soil samples varies with the depth in the soil due to the diminishing effect of seasonality and evaporation. Every high elevation (>3500m) soil profile we measured had nearly constant δ18O values below 5cm and a total range of δ18O values between -12.8‰ and -17.1‰, apart from the Cusco profile. In the Cusco profile, the δ18O values ranged from -7.2 ‰ at 5 cm to -21.8 ‰ at 60 cm, defining a strong monotonic decrease not seen in other soil profiles. The δ18O trend in the Cusco profile may be different due to the impact of evaporation, soil hydrology, and/or seasonality in the δ18O values of precipitation. Further spatial analysis must be conducted to pinpoint a specific cause. Considering only the samples collected below 40cm, which are likely the best estimate of mean annual precipitation, the δ18O values decrease with increasing elevation at a rate higher than the global mean, suggesting that oxygen isotope paleoaltimetry can work in this study region.

  2. Regression-based season-ahead drought prediction for southern Peru conditioned on large-scale climate variables

    Science.gov (United States)

    Mortensen, Eric; Wu, Shu; Notaro, Michael; Vavrus, Stephen; Montgomery, Rob; De Piérola, José; Sánchez, Carlos; Block, Paul

    2018-01-01

    Located at a complex topographic, climatic, and hydrologic crossroads, southern Peru is a semiarid region that exhibits high spatiotemporal variability in precipitation. The economic viability of the region hinges on this water, yet southern Peru is prone to water scarcity caused by seasonal meteorological drought. Meteorological droughts in this region are often triggered during El Niño episodes; however, other large-scale climate mechanisms also play a noteworthy role in controlling the region's hydrologic cycle. An extensive season-ahead precipitation prediction model is developed to help bolster the existing capacity of stakeholders to plan for and mitigate deleterious impacts of drought. In addition to existing climate indices, large-scale climatic variables, such as sea surface temperature, are investigated to identify potential drought predictors. A principal component regression framework is applied to 11 potential predictors to produce an ensemble forecast of regional January-March precipitation totals. Model hindcasts of 51 years, compared to climatology and another model conditioned solely on an El Niño-Southern Oscillation index, achieve notable skill and perform better for several metrics, including ranked probability skill score and a hit-miss statistic. The information provided by the developed model and ancillary modeling efforts, such as extending the lead time of and spatially disaggregating precipitation predictions to the local level as well as forecasting the number of wet-dry days per rainy season, may further assist regional stakeholders and policymakers in preparing for drought.

  3. 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

  4. Revision of Gymnotus (Gymnotiformes: Gymnotidae) from the Upper Madeira Basin of Bolivia and Peru, with descriptions of two new species.

    Science.gov (United States)

    Craig, Jack M; Correa-roldÁn, Vanessa; Ortega, HernÁn; Crampton, William G R; Albert, James S

    2018-04-20

    Banded Knifefishes (Gymnotus, Gymnotidae) comprise the most species-rich genus of Neotropical electric fishes, with 41 species currently described from throughout the humid Neotropics, from Mexico to Argentina. Despite substantial alpha-taxonomic work in recent years, the diversity of Gymnotus in some regions remains poorly understood. Here we describe the Gymnotus fauna of the Upper Madeira basin of Bolivia and Peru from examination of more than 240 adult specimens. Species are delimited and described using body proportions (traditional morphometrics), fin-ray, squamation and laterosensory-pore counts (meristics), quantitative shape differences (geometric morphometrics), osteological traits, and color patterns. Comparisons of standardized linear measures as well as multivariate statistical methods validate the presence in the Upper Madeira basin of three previously described species, two with wide-spread geographic distributions throughout Greater Amazonia (G. carapo and G. coropinae), and one (G. chaviro) endemic to southwestern Amazonia. We also diagnose and describe two new species that are endemic to the Upper Madeira basin: G. eyra n. sp., morphologically most similar to G. mamiraua from lowland Amazonia, and G. riberalta n. sp., morphologically most similar to G. pantanal from the Paraguay-Paraná basin. The five Gymnotus species from the Upper Madeira basin are not monophyletic, each species being more closely related to a different species from another region; i.e. the Gymnotus species from the Upper Madeira represents a polyphyletic assemblage. These descriptions to 43 the number of valid Gymnotus species.

  5. Mass Balance of Cenozoic Andes-Amazon Source to Sink System—Marañón Basin, Peru

    Directory of Open Access Journals (Sweden)

    Gérôme Calvès

    2018-05-01

    Full Text Available We investigate the mass balance of the Cenozoic Andes-Amazon source to sink system using rock uplift proxies and solid sedimentation of the Marañón Basin in Peru. The evolution of sedimentation rates is calibrated with regional structural restored cross-section. The quantification of eroded sediments from reliefs to sedimentary basin is achieved with ×10 Myr resolution and compared to present day proxies from the HYBAM (HYdrologie et Biogéochimie du Bassin Amazonien Critical Zone Observatory. Erosion of the early Andean landforms started during the Upper Mesozoic period, but sediment rates significantly increase during the Neogene. This is in agreement with the calibrated increase of rock uplift in the Andean orogenic belt.

  6. A new species of Acanthoscurria (Araneae: Theraphosidae: Theraphosinae without stridulatory organ, from southern Peru

    Directory of Open Access Journals (Sweden)

    Nelson Ferretti

    2016-08-01

    Full Text Available Acanthoscurria sacsayhuaman sp. nov. (Araneae: Theraphosidae is described based on a male from Cusco, Peru. The new species is characterized by the absence of stridulatory bristles on retrolateral face of palpal trochanter. Moreover, it can be distinguished by morphology of the male palpal bulb and tibial apophysis of the first pair of legs. The genus is recorded for the first time for Peru.

  7. Evaluation of site effects in Loja basin (southern Ecuador)

    Science.gov (United States)

    Guartán, J.; Navarro, M.; Soto, J.

    2013-05-01

    Site effect assessment based on subsurface ground conditions is often crucial for estimating the urban seismic hazard. In order to evaluate the site effects in the intra-mountain basin of Loja (southern Ecuador), geological and geomorphological survey and ambient noise measurements were carried out. A classification of shallow geologic materials was performed through a geological cartography and the use of geotechnical data and geophysical surveys. Seven lithological formations have been analyzed, both in composition and thickness of existing materials. The shear-wave velocity structure in the center of the basin, composed by alluvial materials, was evaluated by means of inversion of Rayleigh wave dispersion data obtained from vertical-component array records of ambient noise. VS30 structure was estimated and an average value of 346 m s-1 was obtained. This value agrees with the results obtained from SPT N-value (306-368 m s-1). Short-period ambient noise observations were performed in 72 sites on a 500m × 500m dimension grid. The horizontal-to-vertical spectral ratio (HVSR) method was applied in order to determine a ground predominant period distribution map. This map reveals an irregular distribution of predominant period values, ranged from 0.1 to 1.0 s, according with the heterogeneity of the basin. Lower values of the period are found in the harder formation (Quillollaco formation), while higher values are predominantly obtained in alluvial formation. These results will be used in the evaluation of ground dynamic properties and will be included in seismic microzoning of Loja basin. Keywords: Landform classification, Ambient noise, SPAC method, Rayleigh waves, Shear velocity profile, Ground predominant period. ;

  8. Numerical modelling of Quaternary terrace staircase formation in the Ebro foreland basin, southern Pyrenees, NE Iberia

    NARCIS (Netherlands)

    van Balen, R.T.; Stange, K.M.; Cloetingh, S.A.P.L.; Garcia-Castellanos, D.

    2016-01-01

    The southern foreland basin of the Pyrenees (Ebro basin) is an exorheic drainage basin since Late Miocene times. Remnants of an early exorheic Ebro drainage system are not preserved, but morphology provides evidence for the Pliocene–Quaternary drainage development. The incision history of the Ebro

  9. 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

  10. Liquification and soft-sediment deformation in a limestone megabreccia: The Ayabacas giant collapse, Cretaceous, southern Peru

    Science.gov (United States)

    Callot, Pierre; Odonne, Francis; Sempere, Thierry

    2008-12-01

    In the back-arc basin of southern Peru, the bulk of the mid-Cretaceous carbonate platform collapsed near the Turonian-Coniacian boundary (~ 90-89 Ma), due to slope creation and resulting oversteepening. The resulting mass-wasting deposits, namely the Ayabacas Formation, consist of a megabreccia which is organised from NE to SW in relation with two major fault systems. Facies of sediment reworking (such as brecciation, liquification, sedimentary dykes and soft-sediment deformation) are described and four types of resedimentation facies are define. In the northeastern part of the study area, deposits mainly consist of a mixture of very heterometric clasts and blocks (millimetric to kilometric in size), mainly carbonate but also sandy-marly in nature, floating in sandy-marly matrix that exhibits features of liquification (sedimentary dykes and flows) and plastic deformation. Here, resedimentation facies are characterized by deformations and a brecciated facies at each observation scale (from aerial photographs to thin sections) and are therefore defined as fractal or multi-scale breccias. Some clasts and large amounts of the matrix were derived from the underlying clay-rich sandstones of the Murco Formation. These materials were prone to liquification and plastic deformation, allowing them to act as a sliding sole that facilitated the slides and the downslope movement of large limestone rafts. In the southwestern part of the study area, only limestone breccias are observed, in alternation with well-stratified levels. The sliding sole of plastically deformable siliciclastic sediments that previously acted as a lubricating layer was not present here, as materials were more deeply buried. Variations in the degree of sediment lithification from northeast to southwest are inferred to have existed before the collapse and also within the sedimentary succession in the northeastern part. In particular, limestones were well-cemented at the base of the carbonate succession and

  11. 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

  12. A geochemical model of the Peru Basin deep-sea floor—and the response of the system to technical impacts

    Science.gov (United States)

    König, Iris; Haeckel, Matthias; Lougear, André; Suess, Erwin; Trautwein, Alfred X.

    A geochemical model of the Peru Basin deep-sea floor, based on an extensive set of field data as well as on numerical simulations, is presented. The model takes into account the vertical oscillations of the redox zonation that occur in response to both long-term (glacial/interglacial) and short-term (El Niño Southern Oscillation (ENSO) time scale) variations in the depositional flux of organic matter. Field evidence of reaction between the pore water NO 3- and an oxidizable fraction of the structural Fe(II) in the clay mineral content of the deep-sea sediments is provided. The conditions of formation and destruction of reactive clay Fe(II) layers in the sea floor are defined, whereby a new paleo-redox proxy is established. Transitional NO 3- profile shapes are explained by periodic contractions and expansions of the oxic zone (ocean bottom respiration) on the ENSO time scale. The near-surface oscillations of the oxic-suboxic boundary constitute a redox pump mechanism of major importance with respect to diagenetic trace metal enrichments and manganese nodule formation, which may account for the particularly high nodule growth rates in this ocean basin. These conditions are due to the similar depth ranges of both the O 2 penetration in the sea floor and the bioturbated high reactivity surface layer (HRSL), all against the background of ENSO-related large variations in depositional C org flux. Removal of the HRSL in the course of deep-sea mining would result in a massive expansion of the oxic surface layer and, thus, the shut down of the near-surface redox pump for centuries, which is demonstrated by numerical modeling.

  13. 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)

    Miyashita, A.

    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

  14. Soil moisture monitoring in Candelaro basin, Southern Italy

    Science.gov (United States)

    Campana, C.; Gigante, V.; Iacobellis, V.

    2012-04-01

    The signature of the hydrologic regime can be investigated, in principle, by recognizing the main mechanisms of runoff generation that take place in the basin and affect the seasonal behavior or the rainfall-driven events. In this framework, besides the implementation of hydrological models, a crucial role should be played by direct observation of key state variables such as soil moisture at different depths and different distances from the river network. In fact, understanding hydrological systems is often limited by the frequency and spatial distribution of observations. Experimental catchments, which are field laboratories with long-term measurements of hydrological variables, are not only sources of data but also sources of knowledge. Wireless distributed sensing platforms are a key technology to address the need for overcoming field limitations such as conflicts between soil use and cable connections. A stand-alone wireless network system has been installed for continuous monitoring of soil water contents at multiple depths along a transect located in Celone basin (sub-basin of Candelaro basin in Puglia, Southern Italy). The transect consists of five verticals, each one having three soil water content sensors at multiple depths: 0,05 m, 0,6 m and 1,2 m below the ground level. The total length of the transect is 307 m and the average distance between the verticals is 77 m. The main elements of the instrumental system installed are: fifteen Decagon 10HS Soil Moisture Sensors, five Decagon Em50R Wireless Radio Data Loggers, one Rain gauge, one Decagon Data Station and one Campbell CR1000 Data Logger. Main advantages of the system as described and presented in this work are that installation of the wireless network system is fast and easy to use, data retrieval and monitoring information over large spatial scales can be obtained in (near) real-time mode and finally other type of sensors can be connected to the system, also offering wide potentials for future

  15. On the Relationship of Dynamic Forearc Processes in Southern Peru to the Development and Preservation of Andean Topography

    Science.gov (United States)

    Hall, S. R.; Farber, D. L.; Audin, L.; Saillard, M.; Finkel, R. C.

    2008-12-01

    After more than 40 years of study, the timing and nature of Andean uplift remains an area of great scientific debate. The forearc of the Andean margin is of particular neotectonic interest, as previous models of Andean orogenesis attributed little-no Neogene deformation to the western margin of Altiplano. However, using the combination of remote sensing with high-resolution data, in situ cosmogenic isotope concentrations and thermochronology, in recent years the community has made important advances in addressing the rates, timings, styles, and locations of active deformation within the forearc of the Andean margin. To first order, we find that - both in terms of tectonics and climate - since 10Ma, the Andean forearc has been quite a dynamic region. Neotectonic studies in this region have been facilitated by the high degree of geomorphic surface preservation that the hyperarid (for at least the last 3My) coastal Atacama Desert has provided. Specifically, in southern Peru (14°-18°S), vast pediment surfaces have been abandoned through incision along the major river drainages that carve the deep canyons into the Precordillera and Western Cordillera. While the exact timing of the periods of more intense incision plausibly correspond with climate events, the total amount of incision integrated over many climate cycles is a useful indicator of tectonic activity. In this region, we find a number of geomorphic and structural features that provide strong evidence for distributed crustal deformation along range-sub-parallel contractile and strike-slip structures. Specifically, we see 1) ancient surfaces reflecting erosion rates as low as chronologies, and 6) Pleistocene mass-wasting events accommodating the redistribution of ~109-1010 m3 of material per event. Furthermore, the observation that Pleistocene incision rates are comparable with Late Miocene and Pliocene rates, suggests to us, that the rates and style of surface uplift within the forearc of southern Peru has

  16. Quaternary Tectonic and Climatic Processes shaping the Central Andean hyperarid forearc (southern Peru)

    Science.gov (United States)

    Audin, Laurence; Benavente, Carlos; Zerathe, Swann; Saillard, Marianne; Hall, Sarah R.; Farber, Daniel L.

    2015-04-01

    Understanding the forearc structure and processes related to Quaternary evolution and uplift of the Western Andean Cordillera remains an outstanding scientific issue. Models of Andean Plateau evolution based on Tertiary volcanic stratigraphy since 5Ma suggest that the deformation was focused along the eastern margin of the plateau and that minimal uplift occurred along the Pacific margin. On the contrary, new tectonic data and Quaternary surface 10Be dating highlight the presence of recently active deformation, incision and alluvial processes within the upper Andean forearc together with a regional uplift of the coastal zone. Additionally, the high obliquity observed in the northern Arica Bend region makes it an ideal target to discuss whether partitioning of the oblique convergence is accommodated by the neotectonic features that dissect the Quaternary forearc. Our goals are both to decipher the Quaternary tectonic and climatic processes shaping the hyperarid forearc along strike and across strike. Finally, we aim to quantify the respective influence of these factors in the overall uplift of the Western Andes. Indeed, sequences of pediment surfaces, landslide products, paleolake deposits and marine terraces found along the oblique Peruvian margin are a unique set of datable markers that can be used to quantify the rates of Quaternary processes. In this study, we focus on the southern Peru hyperarid Atacama area where regional surfaces and tectonic markers (scarps, folds, temporary streams and paleolake levels offsets…) are well preserved for the Quaternary timescale. Numerous landsliding events align on the major fault segments and reflect Plio-Pleistocene climatic and tectonic activity together with filled and strath terraces. As the present day sea-level is one of the highest levels recorded for Quaternary time span, any emerged marine terrace is preserved by tectonic coastal uplift. In particular, the geomorphic and chronologic correlation between marine and

  17. Epidemiology of Spotted Fever Group and Typhus Group Rickettsial Infection in the Amazon Basin of Peru

    Science.gov (United States)

    2010-01-01

    addition, partial citrate synthase (gltA) and outer membrane protein A (ompA) gene sequences were amplified and analyzed, using previously described...views expressed in this article are those of the author and do not necessarily reflect the official policy or position of the Department of the...rickettsial and leptospira infections in Andean northern Peru. Am J Trop Med Hyg 70: 357-363. 21. Schoeler GB, Moron C, Richards A, Blair PJ, Olson JG, 2005

  18. It's about time? Testing the Dawson ceramic seriation using luminescence dating, Southern Nasca Region, Peru

    OpenAIRE

    Vaughn, KJ; Eerkens, JW; Lipo, C; Sakai, S; Schreiber, K

    2014-01-01

    Copyright © 2014 by the Society for American Archaeology. The Dawson seriation of Nasca ceramics has long been assumed to be an accurate marker of temporal changes in the pre-hispanic south coast of Peru. We test this assumption by directly dating a sample of sherds using Optically Stimulated Luminescence (OSL). Our results suggest that while some phases of the seriation are valid chronological markers, others appear to be the result of factors other than time. We discuss the implications of ...

  19. Human T-lymphotropic virus type 1 infection is frequent in rural communities of the southern Andes of Peru.

    Science.gov (United States)

    Ita, Fanny; Mayer, Erick F; Verdonck, Kristien; Gonzalez, Elsa; Clark, Daniel; Gotuzzo, Eduardo

    2014-02-01

    To evaluate the presence of human T-lymphotropic virus type 1 (HTLV-1) infection in isolated rural communities in the southern Andes of Peru. We conducted a cross-sectional study in five communities located in three provinces in Ayacucho, Peru. The five communities are located at >3000 meters above sea level and are mainly rural, and more than 85% of the population speaks Quechua. Volunteers aged 12 years and older were included. Clinical and epidemiological data were collected, along with a blood sample for serological testing. We included 397 participants; their median age was 41 years (interquartile range 31-57 years) and 69% were women. According to our definitions, 98% were of Quechua origin. HTLV-1 was diagnosed in 11 people: 0/164 in Cangallo, 3/154 (2%) in Vilcashuaman, and 8/79 (10%) in Parinacochas. There were no cases of HTLV-2. All the HTLV-1-positive participants were born in Ayacucho and were of Quechua origin; they ranged in age from 29 to 87 years (median 56 years) and 10/11 were women. Ten were apparently healthy, and one woman was diagnosed with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Three out of 11 had a family member with a lower limb impairment compatible with HAM/TSP. The fact that HTLV-1 infection was present in two out of three provinces suggests that HTLV-1 could be highly endemic in the southern Andes in the Quechua population. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. Granitic rocks from the southern Gyeongsang basin, southeastern Korea, (1)

    International Nuclear Information System (INIS)

    Lee, Yoon-Jong

    1980-01-01

    In southern Gyeongsang basin, southeastern Korea, there are many granitic rock masses. They were divided into 7 groups according to their geological evidences. K-Ar age was determined on 36 samples obtained from the respective groups. Group A: pre-Gyeongsang granitic rock (Pre-Cretaceous), A 1 220 m.y., A 2 166 m.y.; group B: outer zone granitic rock (Cretaceous), 115-72 m.y.; group C: ditto (ditto), 97-70 m.y.; group D: ditto (ditto), 89-68 m.y.; group E: ditto (ditto), 82-68 m.y.; group F: inner zone granitic rock (Cretaceous), 75-74 m.y.; group G: Tertiary granitic rock, 63-41 m.y. The large part of the Cretaceous granitic masses show the double elongated ring form. Most of the Tertiary granitic rocks were probably emplaced in close relation with the Eonyang fault line and Ulsan fault line/or their extension line of the area. (J.P.N.)

  1. Oil, gas potential in shallow water: Peru`s continental shelf basins

    Energy Technology Data Exchange (ETDEWEB)

    Zuniga-Rivero, F.; Keeling, J.A.; Hay-Roe, H. [BPZ and Associates Inc., Houston, TX (United States)

    1998-11-16

    This third article of a series highlights the three sedimentary basins that underlie the 16 million acres of continental shelf adjacent to a 650-mile stretch of Peruvian coastline. This area lies roughly between the ports of Chiclayo and Pisco. These basins offer a variety of reservoirs, traps, and source-rock potential in water depths of less than 1,000 ft. They are characterized by a thick sequence of Neogene strata, underlain by Paleogene, Mesozoic, and Upper Paleozoic sediments down to as much as 7 sec two-way time on modern seismic records. In some places the sedimentary section may reach an aggregate thickness in excess of 50,000 ft. From north to south these contiguous shelf basins are the Sechura-Salaverry, Huacho, and Pisco basins. All three basins are described.

  2. Hydrological Modeling in temporary streams: A case study in Pardiela basin, Southern Portugal

    OpenAIRE

    PEDRO, A.; MORAIS, M.; ROSADO, J.; SILVA, H.; SERAFIM, A.; NEVES, R.; BRITO, D.; POTES, M.; SALGADO, R.; LILLEBØ, I.; CHAMBEL, A.

    2011-01-01

    The project “Conservation and rehabilitation strategies for temporary Mediterranean river corridors: a case study on Pardiela basin, southern Portugal (Guadiana basin)", is being carried out,with the collaboration of researchers from diverse scientific areas, in order to increase the knowledge on temporary streams. The project includes different approaches at reach and basin scales, regarding the study of temporal interactions among different ecological components such as climate, morph...

  3. An integrated geodetic and seismic study of the Cusco Fault system in the Cusco Region-Southern Peru

    Science.gov (United States)

    Norabuena, E. O.; Tavera, H. J.

    2017-12-01

    The Cusco Fault system is composed by six main faults (Zurite, Tamboray, Qoricocha, Tambomachay, Pachatusan, and Urcos) extending in a NW-SE direction over the Cusco Region in southeastern Peru. From these, the Tambomachay is a normal fault of 20 km length, strikes N120°E and bounds a basin filled with quaternary lacustrine and fluvial deposits. Given its 5 km distance to Cusco, an historical and Inca's archeological landmark, it represents a great seismic hazard for its more than 350,000 inhabitants. The Tambomachay fault as well as the other secondary faults have been a source of significant seismic activity since historical times being the more damaging ones the Cusco earthquakes of 1650, 1950 and more recently April 1986 (M 5.8). Previous geological studies indicate that at the beginning of the Quaternary the fault showed a transcurrent mechanism leading to the formation of the Cusco basin. However, nowadays its mechanism is normal fault and scarps up to 22m can be observed. We report the current dynamics of the Tambomachay fault and secondary faults based on seismic activity imaged by a network of 29 broadband stations deployed in the Cusco Region as well as the deformation field inferred from GPS survey measurements carried out between 2014 and 2016.

  4. 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.

  5. 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.

  6. 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

  7. Assessing hydrological changes in a regulated river system over the last 90 years in Rimac Basin (Peru)

    Science.gov (United States)

    Vega-Jácome, Fiorella; Lavado-Casimiro, Waldo Sven; Felipe-Obando, Oscar Gustavo

    2018-04-01

    Hydrological changes were assessed considering possible changes in precipitation and regulation or hydraulic diversion projects developed in the basin since 1960s in terms of improving water supply of the Rimac River, which is the main source of fresh water of Peru's capital. To achieve this objective, a trend analysis of precipitation and flow series was assessed using the Mann-Kendall test. Subsequently, the Eco-flow and Indicators of Hydrologic Alteration (IHA) methods were applied for the characterization and quantification of the hydrological change in the basin, considering for the analysis, a natural period (1920-1960) and an altered period (1961-2012). Under this focus, daily hydrologic information of the "Chosica R-2" station (from 1920 to 2013) and monthly rainfall information related to 14 stations (from 1964 to 2013) were collected. The results show variations in the flow seasonality of the altered period in relation to the natural period and a significant trend to increase (decrease) minimum flows (maximum flows) during the analyzed period. The Eco-flow assessment shows a predominance of Eco-deficit from December to May (rainy season), strongly related to negative anomalies of precipitation. In addition, a predominance of Eco-surplus was found from June to November (dry season) with a behavior opposite to precipitation, attributed to the regulations and diversion in the basin during that period. In terms of magnitude, the IHA assessment identified an increase of 51% in the average flows during the dry season and a reduction of 10% in the average flows during the rainy season (except December and May). Furthermore, the minimum flows increased by 35% with shorter duration and frequency, and maximum flows decreased by 29% with more frequency but less duration. Although there are benefits of regulation and diversion for developing anthropic activities, the fact that hydrologic alterations may result in significant modifications in the Rimac River ecosystem

  8. Moessbauer, X-ray fluorescence and paleomagnetic studies of deep-sea sediments from Peru Basin: two million years of sedimentation history

    International Nuclear Information System (INIS)

    Drodt, M.; Trautwein, A.X.; Dekkers, M.J.

    1996-01-01

    Sediment cores with different sub-bottom depths (I: 45 cm and II: 700 cm) from the Peru Basin have been investigated. From the depth profile of the relative amount of Fe(II) a redox zone is obtained which correlates with the organic carbon flux into the sediment (core I). Moessbauer parameters suggest that the iron in the sediments is mainly contained in clay minerals and to varying extent also in goethite

  9. 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.

  10. End Late Paleozoic tectonic stress field in the southern edge of Junggar Basin

    Directory of Open Access Journals (Sweden)

    Wei Ju

    2012-09-01

    Full Text Available This paper presents the end Late Paleozoic tectonic stress field in the southern edge of Junggar Basin by interpreting stress-response structures (dykes, folds, faults with slickenside and conjugate joints. The direction of the maximum principal stress axes is interpreted to be NW–SE (about 325°, and the accommodated motion among plates is assigned as the driving force of this tectonic stress field. The average value of the stress index R′ is about 2.09, which indicates a variation from strike-slip to compressive tectonic stress regime in the study area during the end Late Paleozoic period. The reconstruction of the tectonic field in the southern edge of Junggar Basin provides insights into the tectonic deformation processes around the southern Junggar Basin and contributes to the further understanding of basin evolution and tectonic settings during the culmination of the Paleozoic.

  11. Evidence of transboundary mercury and other pollutants in the Puyango-Tumbes River basin, Ecuador-Peru.

    Science.gov (United States)

    Marshall, Bruce G; Veiga, Marcello M; Kaplan, Robert J; Adler Miserendino, Rebecca; Schudel, Gary; Bergquist, Bridget A; Guimarães, Jean R D; Sobral, Luis G S; Gonzalez-Mueller, Carolina

    2018-04-25

    In Portovelo in southern Ecuador, 87 gold processing centers along the Puyango-Tumbes River produce an estimated 6 tonnes of gold per annum using a combination of mercury amalgamation and/or cyanidation and processing poly-metallic ores. We analysed total Hg, Hg isotopes, total arsenic, cadmium, copper, lead and zinc in water and sediment along the Puyango in 2012-2014. The highest total mercury (THg) concentrations in sediments were found within a 40 km stretch downriver from the processing plants, with levels varying between 0.78-30.8 mg kg-1 during the dry season and 1.80-70.7 mg kg-1 during the wet season, with most concentrations above the CCME (Canadian Council of Ministers of the Environment) Probable Effect Level (PEL) of 0.5 mg kg-1. Data from mercury isotopic analyses support the conclusion that mercury use during gold processing in Portovelo is the source of Hg pollution found downstream in the Tumbes Delta in Peru, 160 km away. The majority of the water and sediment samples collected from the Puyango-Tumbes River had elevated concentrations of, arsenic, cadmium, copper, lead and zinc exceeding the CCME thresholds for the Protection of Aquatic Life. At monitoring points immediately below the processing plants, total dissolved concentrations of these metals exceeded the thresholds by 156-3567 times in surface waters and by 19-740 times in sediment. The results illustrate a significant transboundary pollution problem involving Hg and other toxic metals, amplified by the fact that the Puyango-Tumbes River is the only available water source in the semi-arid region of northern Peru.

  12. Petroleum geological atlas of the southern permian basin area -Overview SPB-atlas project-organisation and results

    NARCIS (Netherlands)

    Doornenbal, J.C.; Abbink, O.A.; Pagnier, H.J.M.; Wees, J.D. van

    2009-01-01

    The Southern Permian Basin (also referred to as Central European Basin) is Europe s largest sedimentary basin. It is a typical intracontinental basin that evolved from latest Carboniferous to recent times and extends from eastern England to the Belarussian-Polish border and from Denmark to South

  13. 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

  14. 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

  15. Multiproxy records of Holocene climate and glacier variability from sediment cores in the Cordillera Vilcabamba of southern Peru

    Science.gov (United States)

    Schweinsberg, A. D.; Licciardi, J. M.; Rodbell, D. T.; Stansell, N.; Tapia, P. M.

    2012-12-01

    Sediments contained in glacier-fed lakes and bogs provide continuous high-resolution records of glacial activity, and preserve multiproxy evidence of Holocene climate change. Tropical glacier fluctuations offer critical insight on regional paleoclimatic trends and controls, however, continuous sediment records of past tropical climates are limited. Recent cosmogenic 10Be surface exposure ages of moraine sequences in the Cordillera Vilcabamba of southern Peru (13°20'S latitude) reveal a glacial culmination during the early Holocene and a less extensive glaciation coincident with the Little Ice Age of the Northern Hemisphere. Here we supplement the existing 10Be moraine chronology with the first continuous records of multiproxy climate data in this mountain range from sediment cores recovered from bogs in direct stratigraphic contact with 10Be-dated moraines. Radiocarbon-dated sedimentological changes in a 2-meter long bog core reveal that the Holocene is characterized by alternating inorganic and organic-rich laminae, suggesting high-frequency climatic variability. Carbon measurements, bulk density, and bulk sedimentation rates are used to derive a record of clastic sediment flux that serves as a proxy indicator of former glacier activity. Preliminary analyses of the bog core reveal approximately 70 diatom taxa that indicate both rheophilic and lentic environments. Initial results show a general decrease in magnetic susceptibility and clastic flux throughout the early to mid-Holocene, which suggests an interval of deglaciation. An episode of high clastic flux from 3.8 to 2.0 ka may reflect a late Holocene glacial readvance. Volcanic glass fragments and an anomalous peak in magnetic susceptibility may correspond to the historical 1600 AD eruption of Huaynaputina. Ten new bog and lake sediment cores were collected during the 2012 field expedition and analytical measurements are underway. Ongoing efforts are focused on analyzing diatom assemblage data, developing

  16. Miocene fish faunas from the northwestern Amazonia basin (Colombia, Peru, Brazil) with evidence of marine incursions

    NARCIS (Netherlands)

    Monsch, KA

    1998-01-01

    New evidence indicates marine influences during the Miocene in the northwestern Amazonia basin. This is the first major survey of the ichthyofauna from this area in the Miocene. Fossil fish remains from taxa such as the Dasyatoidea, Myliobatoidea, Characiformes, Siluriformes and Sciaenidae are

  17. Mössbauer investigations to characterize Fe lattice sites in sheet silicates and Peru Basin deep-sea sediments

    Science.gov (United States)

    Lougear, André; König, Iris; Trautwein, Alfred X.; Suess, Erwin

    A procedure to classify different Fe lattice sites, i.e., OH-group geometries, in the clay mineral content of deep-sea sediments was developed using Mössbauer spectroscopy at low temperature (77 K). This speciation is of interest with regard to the redox behavior, reactivity and color of marine sediments, since substantial iron redox transitions (associated with sediment color change) have been documented for the structural sheet silicate iron. Lattice site classification was achieved for the Fe(II) fraction, all of which is structural clay Fe(II) in the sediments under investigation. Whereas the major part of the Fe(III) is structural clay iron as well, there is a small Fe(III) fraction in oxide minerals. Therefore, further elaboration of the procedure would be required to also achieve lattice site classification for the Fe(III) fraction. Analysis of the Mössbauer spectra is based on computer fits, the input parameters of which were derived from a separate study of Fe(II)-rich pure chlorites. The procedure of classification is qualified to investigate, e.g., in laboratory experiments, the site-specific reaction rates and the effects on sediment color of iron redox transitions in the sheet silicate content of sediments. The new skills were successfully applied in environmental impact studies on the mining of polymetallic nodules from the Peru Basin deep-sea floor.

  18. USING SRTM TO QUANTIFY SIZE PARAMETERS AND SPATIAL DISTRIBUTION OF ENDORHEIC BASINS IN SOUTHERN SOUTH AMERICA

    Directory of Open Access Journals (Sweden)

    Ralf Hesse

    2008-08-01

    Full Text Available The SRTM data set is the highest resolution DEM with global or continental coverage. It is therefore theDEM of choice for continental-scale geomorphological mapping and quantitative analysis. In this study,SRTM data are used for the identification and characterisation of endorheic basins in southern SouthAmerica (south of 19°S. The results show the feasibility of continental-scale quantitative geomorphologybased on SRTM data and provide insights into the distribution of closed basins. The largest endorheicbasin is located in the Puna region and consists of several interconnected sub-basins. This basin accountsfor 38.6 % (7877 km3 of the total volume of the endorheic basins identified in this study. Analyses of thegeographic distribution show a narrow longitudinal distribution between 64.5 and 71.5° W and a multimodallatitudinal distribution which is characterised by two groups of basins at 22.5–27.5°S and 37.5–50.0° Sand an almost complete absence of basins between 27.5 and 37.5° S. Problems and sources ofmisinterpretation arising from data quality and resolution are discussed. Further research, targeting in particularthe genesis and potential for paleoenvironmental reconstruction of closed basins in southern Argentina, iscalled for.

  19. Investigating regional mobility in the southern hinterland of the Wari Empire: biogeochemistry at the site of Beringa, Peru.

    Science.gov (United States)

    Knudson, Kelly J; Tung, Tiffiny A

    2011-06-01

    Empires have transformed political, social, and environmental landscapes in the past and present. Although much research on archaeological empires focuses on large-scale imperial processes, we use biogeochemistry and bioarchaeology to investigate how imperialism may have reshaped regional political organization and regional migration patterns in the Wari Empire of the Andean Middle Horizon (ca. AD 600-1000). Radiogenic strontium isotope analysis of human remains from the site of Beringa in the Majes Valley of southern Peru identified the geographic origins of individuals impacted by the Wari Empire. At Beringa, the combined archaeological human enamel and bone values range from (87)Sr/(86)Sr = 0.70802 - 0.70960, with a mean (87)Sr/(86)Sr = 0.70842 ± 0.00027 (1σ, n = 52). These data are consistent with radiogenic strontium isotope data from the local fauna in the Majes Valley and imply that most individuals were local inhabitants, rather than migrants from the Wari heartland or some other locale. There were two outliers at Beringa, and these "non-local" individuals may have derived from other parts of the South Central Andes. This is consistent with our understanding of expansive trade networks and population movement in the Andean Middle Horizon, likely influenced by the policies of the Wari Empire. Although not a Wari colony, the incorporation of small sites like Beringa into the vast social and political networks of the Middle Horizon resulted in small numbers of migrants at Beringa. Copyright © 2011 Wiley-Liss, Inc.

  20. 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.

  1. El Niño Variability in the Coastal Desert of Southern Peru during the Mid-Holocene

    Science.gov (United States)

    Fontugne, Michel; Usselmann, Pierre; Lavallée, Danièle; Julien, Michèle; Hatté, Christine

    1999-09-01

    Fourteen organic-rich sedimentary layers in the deposits at Quebrada de los Burros, in coastal southern Peru (Tacna department), lie between two debris-flow units, interpreted to result from El Niño events, at 8980 cal yr B.P. and after 3380 cal yr B.P., respectively. The accumulation of the fine-grained and low-energy sediments of this deposit during the mid-Holocene is incompatible with the occurrence of El Niño events in this region, as these would produce catastrophic flood deposits. The occurrence of organic-rich sediments and evidence of an enhancement of upwelling strength at this time imply the existence of a permanent water supply resulting from an increased condensation of fog at mid-altitudes. These results suggest a lower intensity and, perhaps, a lower frequency of occurrence of the El Niño phenomenon during the mid-Holocene. It is precisely during this period that the most important human settlements are found at this site, probably indicating the presence of reliable supply of fresh water. The chronologies for wetlands in the central south altiplano are out of phase with those indicating increased soil moisture episodes on the coast, implying a long-term difference in climate between these two regions.

  2. Characteristics of registration of medical records in a hospital in southern Peru

    Directory of Open Access Journals (Sweden)

    Cender Udai Quispe-Juli

    2016-04-01

    Full Text Available Objective: To determine the characteristics of registration of medical records of hospitalization in the Hospital III Yanahuara in Arequipa, Peru. Material and methods: The study was observational, cross-sectional and retrospective. 225 medical records of hospitalization were evaluated in November 2015. A tab consisting of 15 items was used; each item was assessed using a scale: "very bad", "bad", "acceptable", "good" and "very good". Adescriptive analysis was done by calculating frequency. Results: Items with a higher proportion of acceptable registration data were: clear therapeutic indication (84%, clinical evolution (74.7%, diagnosis (70.7%, complete and orderly therapeutic indication (54.2%, medical history taking (50.2% and physical examination (43.1%. The very well recorded items were: indication of tests and procedures (97.3%, medical identification (91.1% and allergies (67.1%. Very bad recorded items were: reason for admission (91.1%, life habits (72.9% and prior treatment (38.2%. Conclusions: Most medical records of hospitalization are characterized by an acceptable record of most evaluated items; however they have notable deficiencies in some items.

  3. Southern Peru desert shattered by the great 2001 earthquake: Implications for paleoseismic and paleo-El Niño–Southern Oscillation records

    Science.gov (United States)

    Keefer, David K.; Moseley, Michael E.

    2004-01-01

    In the desert region around the coastal city of Ilo, the great southern Peru earthquake of June 23, 2001 (8.2–8.4 moment magnitude), produced intense and widespread ground-failure effects. These effects included abundant landslides, pervasive ground cracking, microfracturing of surficial hillslope materials, collapse of drainage banks over long stretches, widening of hillside rills, and lengthening of first-order tributary channels. We have coined the term “shattered landscape” to describe the severity of these effects. Long-term consequences of this landscape shattering are inferred to include increased runoff and sediment transport during postearthquake rainstorms. This inference was confirmed during the first minor postearthquake rainstorm there, which occurred in June and July of 2002. Greater amounts of rainfall in this desert region have historically been associated with El Niño events. Previous studies of an unusual paleoflood deposit in this region have concluded that it is the product of El Niño-generated precipitation falling on seismically disturbed landscapes. The effects of the 2001 earthquake and 2002 rainstorm support that conclusion. PMID:15263069

  4. Southern Peru desert shattered by the great 2001 earthquake: implications for paleoseismic and paleo-El Nino-Southern Oscillation records.

    Science.gov (United States)

    Keefer, David K; Moseley, Michael E

    2004-07-27

    In the desert region around the coastal city of Ilo, the great southern Peru earthquake of June 23, 2001 (8.2-8.4 moment magnitude), produced intense and widespread ground-failure effects. These effects included abundant landslides, pervasive ground cracking, microfracturing of surficial hillslope materials, collapse of drainage banks over long stretches, widening of hillside rills, and lengthening of first-order tributary channels. We have coined the term "shattered landscape" to describe the severity of these effects. Long-term consequences of this landscape shattering are inferred to include increased runoff and sediment transport during postearthquake rainstorms. This inference was confirmed during the first minor postearthquake rainstorm there, which occurred in June and July of 2002. Greater amounts of rainfall in this desert region have historically been associated with El Niño events. Previous studies of an unusual paleoflood deposit in this region have concluded that it is the product of El Niño-generated precipitation falling on seismically disturbed landscapes. The effects of the 2001 earthquake and 2002 rainstorm support that conclusion.

  5. The Pindiro Group (Triassic to Early Jurassic Mandawa Basin, southern coastal Tanzania): Definition, palaeoenvironment, and stratigraphy

    Science.gov (United States)

    Hudson, W. E.; Nicholas, C. J.

    2014-04-01

    This paper defines the Pindiro Group of the Mandawa Basin, southern coastal Tanzania based on studies conducted between 2006 and 2009 with the objective of understanding the evolution of this basin. This work draws upon field data, hydrocarbon exploration data, unconventional literature, and the scant published materials available. The paper focuses on the evolution, depositional environments, and definition of the lowermost sedimentary package, which overlies unconformably the metamorphic basement of Precambrian age. The package is described here as the Pindiro Group and it forms the basal group of the Mandawa Basin stratigraphy.

  6. Heavy metal distributions in Peru Basin surface sediments in relation to historic, present and disturbed redox environments

    Science.gov (United States)

    Koschinsky, Andrea

    Heavy metal distributions in deep-sea surface sediments and pore water profiles from five areas in the Peru Basin were investigated with respect to the redox environment and diagenetic processes in these areas. The 10-20-cm-thick Mn oxide-rich and minor metal-rich top layer is underlain by an increase in dissolved Mn and Ni concentrations resulting from the reduction of the MnO 2 phase below the oxic zone. The mobilised associated metals like Co, Zn and Cu are partly immobilised by sorption on clay, organic or Fe compounds in the post-oxic environment. Enrichment of dissolved Cu, Zn, Ni, Co, Pb, Cd, Fe and V within the upper 1-5 cm of the oxic zone can be attributed to the degradation of organic matter. In a core from one area at around 22-25 cm depth, striking enrichments of these metals in dissolved and solid forms were observed. Offset distributions between oxygen penetration and Mn reduction and the thickness of the Mn oxide-rich layer indicate fluctuations of the Mn redox boundary on a short-term time scale. Within the objectives of the German ATESEPP research programme, the effect of an industrial impact such as manganese nodule mining on the heavy metal cycle in the surface sediment was considered. If the oxic surface were to be removed or disturbed, oxygen would penetrate deep into the formerly suboxic sediment and precipitate Mn 2+ and metals like Ni and Co which are preferably scavenged by MnO 2. The solid enrichments of Cd, V, and other metals formed in post-oxic environments would move downward with the new redox boundary until a new equilibrium between oxygen diffusion and consumption is reached.

  7. Seismic evidence of gas hydrates, multiple BSRs and fluid flow offshore Tumbes Basin, Peru

    Science.gov (United States)

    Auguy, Constance; Calvès, Gérôme; Calderon, Ysabel; Brusset, Stéphane

    2017-12-01

    Identification of a previously undocumented hydrate system in the Tumbes Basin, localized off the north Peruvian margin at latitude of 3°20'—4°10'S, allows us to better understand gas hydrates of convergent margins, and complement the 36 hydrate sites already identified around the Pacific Ocean. Using a combined 2D-3D seismic dataset, we present a detailed analysis of seismic amplitude anomalies related to the presence of gas hydrates and/or free gas in sediments. Our observations identify the occurrence of a widespread bottom simulating reflector (BSR), under which we observed, at several sites, the succession of one or two BSR-type reflections of variable amplitude, and vertical acoustic discontinuities associated with fluid flow and gas chimneys. We conclude that the uppermost BSR marks the current base of the hydrate stability field, for a gas composition comprised between 96% methane and 4% of ethane, propane and pure methane. Three hypotheses are developed to explain the nature of the multiple BSRs. They may refer to the base of hydrates of different gas composition, a remnant of an older BSR in the process of dispersion/dissociation or a diagenetically induced permeability barrier formed when the active BSR existed stably at that level for an extended period. The multiple BSRs have been interpreted as three events of steady state in the pressure and temperature conditions. They might be produced by climatic episodes since the last glaciation associated with tectonic activity, essentially tectonic subsidence, one of the main parameters that control the evolution of the Tumbes Basin.

  8. Assessment of undiscovered oil and gas resources of the Susitna Basin, southern Alaska, 2017

    Science.gov (United States)

    Stanley, Richard G.; Potter, Christopher J.; Lewis, Kristen A.; Lillis, Paul G.; Shah, Anjana K.; Haeussler, Peter J.; Phillips, Jeffrey D.; Valin, Zenon C.; Schenk, Christopher J.; Klett, Timothy R.; Brownfield, Michael E.; Drake II, Ronald M.; Finn, Thomas M.; Haines, Seth S.; Higley, Debra K.; Houseknecht, David W.; Le, Phuong A.; Marra, Kristen R.; Mercier, Tracey J.; Leathers-Miller, Heidi M.; Paxton, Stanley T.; Pearson, Ofori N.; Tennyson, Marilyn E.; Woodall, Cheryl A.; Zyrianova, Margarita V.

    2018-05-01

    The U.S. Geological Survey (USGS) recently completed an assessment of undiscovered, technically recoverable oil and gas resources in the Susitna Basin of southern Alaska. Using a geology-based methodology, the USGS estimates that mean undiscovered volumes of about 2 million barrels of oil and nearly 1.7 trillion cubic feet of gas may be found in this area.

  9. Remaining recoverable petroleum in giant oil fields of the Los Angeles Basin, southern California

    Science.gov (United States)

    Gautier, Donald L.; Tennyson, Marilyn E.; Cook, Troy A.; Charpentier, Ronald R.; Klett, Timothy R.

    2012-01-01

    Using a probabilistic geology-based methodology, a team of U.S. Geological Survey (USGS) scientists recently assessed the remaining recoverable oil in 10 oil fields of the Los Angeles Basin in southern California. The results of the assessment suggest that between 1.4 and 5.6 billion barrels of additional oil could be recovered from those fields with existing technology.

  10. Evaluation of water quality at the source of streams of the Sinos River Basin, southern Brazil

    Directory of Open Access Journals (Sweden)

    T Benvenuti

    Full Text Available The Sinos River Basin (SRB is located in the northeastern region of the state of Rio Grande do Sul (29º20' to 30º10'S and 50º15' to 51º20'W, southern Brazil, and covers two geomorphologic provinces: the southern plateau and the central depression. It is part of the Guaíba basin, has an area of approximately 800 km2 and contains 32 counties. The basin provides drinking water for 1.6 million inhabitants in one of the most important industrial centres in Brazil. This study describes different water quality indices (WQI used for the sub-basins of three important streams in the SRB: Pampa, Estância Velha/Portão and Schmidt streams. Physical, chemical and microbiological parameters assessed bimonthly using samples collected at each stream source were used to calculate the Horton Index (HI, the Dinius Index (DI and the water quality index adopted by the US National Sanitation Foundation (NSF WQI in the additive and multiplicative forms. These indices describe mean water quality levels at the streams sources. The results obtained for these 3 indexes showed a worrying scenario in which water quality has already been negatively affected at the sites where three important sub-basins in the Sinos River Basin begin to form.

  11. [Vegetation change of Yamzho Yumco Basin in southern Tibet based on SPOT-VGT NDVI].

    Science.gov (United States)

    Yu, Shu-Mei; Liu, Jing-Shi; Yuan, Jin-Guo

    2010-06-01

    The area we studied is Lake Yamzho Yumco Basin (28 degrees 27'-29 degrees 12'N, 90 degrees 08'-91 degrees 45'E), the largest inland lake basin in southern Tibetan Plateau, China. Using the SPOT-VGT NDVI vegetation index from 1998 to 2007 in the basin, the temporal and spatial variation characteristics of NDVI and its correlation with the major climatic factors (air temperature, precipitation) were analyzed. The results show that the average NDVI of the lake basin ranges from 0.12 to 0.31 and its seasonal change is obvious; the NDVI begins to rise rapidly in May and reaches the maximum value in early September. The average NDVI of the basin shows the slow increasing trend during 1998 to 2007, and it indicates that the eco-environment of the basin is recovering. The high value of NDVI has close relationships with water supply, altitude and vegetation types, so NDVI is relatively high near water sources and is the highest in meadow grassland. The summer air temperature and precipitation are the important climate elements that influence the vegetation in the basin, and the linear correlation coefficients between NDVI and air temperature and precipitation are 0.7 and 0.71, respectively. In recent years, warm and humid trend of the local climate is prevailing to improve the ecological environment in Yamzho Yumco Basin.

  12. 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

  13. Precise Surface Exposure Dating of Early Holocene and Little Ice Age Moraines in the Cordillera Vilcabamba of Southern Peru

    Science.gov (United States)

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

    2008-12-01

    We have established precise ages of two glacial events in the tropical Andean highlands of southern Peru. The field site is located on the flanks of Nevado Salcantay (6271 m asl; 13°20'S latitude), the highest peak in the Cordillera Vilcabamba. A two-fold sequence of nested lateral and end moraines was mapped in a glacial trough emanating from the south face of Salcantay. Well-defined outer and inner moraines were deposited by valley glaciers that terminated 5 km and 3 km, respectively, from their head on the Salcantay massif. Cosmogenic 10Be surface exposure dating of boulders on the outer (n = 7) and inner (n = 7) moraine crests expands upon initial age control for these deposits and improves substantially on the precision of earlier 10Be measurements. The new results yield mean ages of 9.0 ± 0.3 ka for the outer moraine and 195 ± 24 years for the inner moraine, corresponding to glacial events during the early and latest Holocene. These ages are derived using the CRONUS-Earth 10Be exposure age calculator with Lal-Stone production rate scaling and the default height-pressure relationship. The inner moraine age correlates with the timing of the Little Ice Age as defined from northern mid- and high latitude records, and indicates considerable expansion of glaciers heading on Nevado Salcantay during this climatic minimum. Recent geomorphic mapping has identified similar sequences of moraines in adjacent drainages on and near Salcantay, suggesting a broader regional signal of two prominent Holocene glacial events in this segment of the southern Peruvian Andes; 10Be dating of these additional moraines is underway. Our new glacier chronologies complement ice core and lacustrine paleoclimate records in the vicinity, thereby increasing spatial and temporal coverage for identifying patterns of climate change in the tropical Andes during the Holocene. Apart from their paleoclimatic significance, the results also demonstrate a newly- developed capability of 10Be exposure

  14. Understanding strain transfer and basin evolution complexities in the Salton pull-apart basin near the Southern San Andreas Fault

    Science.gov (United States)

    Kell, A. M.; Sahakian, V. J.; Kent, G. M.; Driscoll, N. W.; Harding, A. J.; Baskin, R. L.; Barth, M.; Hole, J. A.; Stock, J. M.; Fuis, G. S.

    2015-12-01

    Active source seismic data in the Salton Sea provide insight into the complexity of the pull-apart system development. Seismic reflection data combined with tomographic cross sections give constraints on the timing of basin development and strain partitioning between the two dominant dextral faults in the region; the Imperial fault to the southwest and the Southern San Andreas fault (SSAF) to the northeast. Deformation associated with this step-over appears young, having formed in the last 20-40 k.a. The complexity seen in the Salton Sea is similar to that seen in pull-apart basins worldwide. In the southern basin of the Salton Sea, a zone of transpression is noted near the southern termination of the San Andreas fault, though this stress regime quickly transitions to a region of transtension in the northern reaches of the sea. The evolution seen in the basin architecture is likely related to a transition of the SSAF dying to the north, and giving way to youthful segments of the Brawley seismic zone and Imperial fault. Stratigraphic signatures seen in seismic cross-sections also reveal a long-term component of slip to the southwest on a fault 1-2 km west of the northeastern Salton Sea shoreline. Numerous lines of evidence, including seismic reflection data, high-resolution bathymetry within the Salton Sea, and folding patterns in the Borrego Formation to the east of the sea support an assertion of a previously unmapped fault, the Salton Trough fault (STF), parallel to the SAF and just offshore within the Salton Sea. Seismic observations are seen consistently within two datasets of varying vertical resolutions, up to depths of 4-5 km, suggesting that this fault strand is much longer-lived than the evolution seen in the southern sub-basin. The existence of the STF unifies discrepancies between the onshore seismic studies and data collected within the sea. The STF likely serves as the current bounding fault to the active pull-apart system, as it aligns with the "rung

  15. 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

  16. Kinship and seasonal migration among the Aymara of southern Peru: human adaptation to energy scarcity

    Energy Technology Data Exchange (ETDEWEB)

    Collins, J.L.

    1981-01-01

    The people of the southern Peruvian highlands have adapted to a condition of energy scarcity through seasonal migration to lowland areas. In the disrict of Sarata (a fictitious name for a real district on the northeastern shore of Lake Titicaca) people spend three to seven months of every year growing coffee in the Tambopata Valley of the eastern Andes. This migratory pattern, which is hundreds of years old, provides the context for an investigation of human adaptive processes. This study presents models of the flow of energy through high-altitude households and shows that energy is a limiting factor for the population. There are two periods when energy subsidies from lowland regions become crucial to the continued survival of highland households. These are the periods of peak growth and reproduction experienced by households early in their developmental cycles, and times of sharply lowered productivity caused by environmental crises such as drought or killing frosts. Seasonal migration provides the subsidies that households rely on during these periods.

  17. Temporal variability and annual budget of inorganic dissolved matter in Andean Pacific Rivers located along a climate gradient from northern Ecuador to southern Peru

    Science.gov (United States)

    Moquet, Jean-Sébastien; Guyot, Jean-Loup; Morera, Sergio; Crave, Alain; Rau, Pedro; Vauchel, Philippe; Lagane, Christelle; Sondag, Francis; Lavado, Casimiro Waldo; Pombosa, Rodrigo; Martinez, Jean-Michel

    2018-01-01

    In Ecuador and Peru, geochemical information from Pacific coastal rivers is limited and scarce. Here, we present an unedited database of major element concentrations from five HYBAM observatory stations monitored monthly between 4 and 10 years, and the discrete sampling of 23 Andean rivers distributed along the climate gradient of the Ecuadorian and Peruvian Pacific coasts. Concentration (C) vs. discharge (Q) relationships of the five monitored basins exhibit a clear dilution behavior for evaporites and/or pyrite solutes, while the solute concentrations delivered by other endmembers are less variable. Spatially, the annual specific fluxes for total dissolved solids (TDS), Ca2+, HCO3-, K+, Mg2+, and SiO2 are controlled on the first order by runoff variability, while Cl-, Na+ and SO42- are controlled by the occurrence of evaporites and/or pyrite. The entire Pacific basin in Ecuador and Peru exported 30 Mt TDS·yr-1, according to a specific flux of ∼70 t·km-2·yr-1. This show that, even under low rainfall conditions, this orogenic context is more active, in terms of solute production, than the global average.

  18. Lithofacies control in detrital zircon provenance studies: Insights from the Cretaceous Methow basin, southern Canadian Cordillera

    Science.gov (United States)

    DeGraaff-Surpless, K.; Mahoney, J.B.; Wooden, J.L.; McWilliams, M.O.

    2003-01-01

    High-frequency sampling for detrital zircon analysis can provide a detailed record of fine-scale basin evolution by revealing the temporal and spatial variability of detrital zircon ages within clastic sedimentary successions. This investigation employed detailed sampling of two sedimentary successions in the Methow/Methow-Tyaughton basin of the southern Canadian Cordillera to characterize the heterogeneity of detrital zircon signatures within single lithofacies and assess the applicability of detrital zircon analysis in distinguishing fine-scale provenance changes not apparent in lithologic analysis of the strata. The Methow/Methow-Tyaughton basin contains two distinct stratigraphic sequences of middle Albian to Santonian clastic sedimentary rocks: submarine-fan deposits of the Harts Pass Formation/Jackass Mountain Group and fluvial deposits of the Winthrop Formation. Although both stratigraphic sequences displayed consistent ranges in detrital zircon ages on a broad scale, detailed sampling within each succession revealed heterogeneity in the detrital zircon age distributions that was systematic and predictable in the turbidite succession but unpredictable in the fluvial succession. These results suggest that a high-density sampling approach permits interpretation of finescale changes within a lithologically uniform turbiditic sedimentary succession, but heterogeneity within fluvial systems may be too large and unpredictable to permit accurate fine-scale characterization of the evolution of source regions. The robust composite detrital zircon age signature developed for these two successions permits comparison of the Methow/Methow-Tyaughton basin age signature with known plutonic source-rock ages from major plutonic belts throughout the Cretaceous North American margin. The Methow/Methow-Tyaughton basin detrital zircon age signature matches best with source regions in the southern Canadian Cordillera, requiring that the basin developed in close proximity to the

  19. The evolution of the magmatic arc of Southern Peru (200-60 Ma), Arequipa area: insight from geochemical modeling

    Science.gov (United States)

    Demouy, S.; Benoit, M.; De Saint Blanquat, M.; Brunet, P.

    2012-12-01

    Cordilleran-type batholiths are built by prolonged arc activity along continental margins and may provide detailed magmatic records of the subduction system evolution. The magmas produced in subduction context involve both mantellic and crustal end members and are subject to various petrological processes. The MASH zones (Hildreth and Moorbath, 1988), at the basis of the continental crust, are the best places for the genesis of such hybrid magmas. The various geochemical signatures observed in the plutonic rocks, may also be attributed to source heterogeneities or generated by subsequent petrological processes. This study has focused in the Arequipa section of the Coastal Batholith of Southern Peru (200-60 Ma), in an area extending over 80x40 km. Major and trace elements as well as Sr and Nd isotopic analyses were performed in a set of 100 samples ranging from gabbro to granite. The obtained data highlight the wide heterogeneity of the geochemical signatures that is not related to the classification of the rocks. In first step, Rb/Sr systematic was used to isolate a set of samples plotting along a Paleocene isochron and defining a cogenetic suite. This suite appears to have evolved by simple fractional crystallization. By using reverse modeling, the parameters controlling the fractional crystallization process were defined, as partition coefficients, initial concentrations and amount of fractional crystallization. The other magmatic suites display a wide range of isotopic and geochemical signatures. To explain this heterogeneity, a model involving competition between fractional crystallization and magma mixing into MASH zones was proposed. A large range of hybrid magma types is potentially generated during the maturation of the system, but this range tends to disappear as fractionation and mixing occurs. Finally the model predicts the genesis of a homogeneous reservoir created at depth, from which magmas may evolve only by fractional crystallization. Therefore

  20. 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

  1. Tsunamigenic scenarios for southern Peru and northern Chile seismic gap: Deterministic and probabilistic hybrid approach for hazard assessment

    Science.gov (United States)

    González-Carrasco, J. F.; Gonzalez, G.; Aránguiz, R.; Yanez, G. A.; Melgar, D.; Salazar, P.; Shrivastava, M. N.; Das, R.; Catalan, P. A.; Cienfuegos, R.

    2017-12-01

    Plausible worst-case tsunamigenic scenarios definition plays a relevant role in tsunami hazard assessment focused in emergency preparedness and evacuation planning for coastal communities. During the last decade, the occurrence of major and moderate tsunamigenic earthquakes along worldwide subduction zones has given clues about critical parameters involved in near-field tsunami inundation processes, i.e. slip spatial distribution, shelf resonance of edge waves and local geomorphology effects. To analyze the effects of these seismic and hydrodynamic variables over the epistemic uncertainty of coastal inundation, we implement a combined methodology using deterministic and probabilistic approaches to construct 420 tsunamigenic scenarios in a mature seismic gap of southern Peru and northern Chile, extended from 17ºS to 24ºS. The deterministic scenarios are calculated using a regional distribution of trench-parallel gravity anomaly (TPGA) and trench-parallel topography anomaly (TPTA), three-dimensional Slab 1.0 worldwide subduction zones geometry model and published interseismic coupling (ISC) distributions. As result, we find four higher slip deficit zones interpreted as major seismic asperities of the gap, used in a hierarchical tree scheme to generate ten tsunamigenic scenarios with seismic magnitudes fluctuates between Mw 8.4 to Mw 8.9. Additionally, we construct ten homogeneous slip scenarios as inundation baseline. For the probabilistic approach, we implement a Karhunen - Loève expansion to generate 400 stochastic tsunamigenic scenarios over the maximum extension of the gap, with the same magnitude range of the deterministic sources. All the scenarios are simulated through a non-hydrostatic tsunami model Neowave 2D, using a classical nesting scheme, for five coastal major cities in northern Chile (Arica, Iquique, Tocopilla, Mejillones and Antofagasta) obtaining high resolution data of inundation depth, runup, coastal currents and sea level elevation. The

  2. 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.

  3. 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

  4. Landslide and glacial lake outburst flood hazard in the Chucchún river basin, Cordillera Blanca, Peru

    Czech Academy of Sciences Publication Activity Database

    Klimeš, Jan; Vilímek, V.; Benešová, M.

    2015-01-01

    Roč. 50, č. 2 (2015), s. 173-180 ISSN 0300-5402 R&D Projects: GA ČR(CZ) GAP209/11/1000 Institutional support: RVO:67985891 Keywords : landslide hazard * GLOFs * flood hazard * Cordillera Blanca * Peru Subject RIV: DE - Earth Magnetism, Geodesy, Geography

  5. 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

  6. Insights on the evolution of mid-ocean basins: the Atlantis Basin of southern Azores

    Science.gov (United States)

    Alves, T.; Bouriak, S.; Volkonskaya, A.; Monteiro, J.; Ivanov, M.

    2003-04-01

    Single-channel seismic reflection and sidescan (OKEAN) data acquired in an unstudied region of the North Atlantic give important insights on the evolution of mid-ocean basins. Located on the eastern flank of the Mid-Atlantic Ridge, south of the Azores Islands, the study area contains more than 1,000 ms two-way travel-time of sediments with a similar seismic stratigraphy to that of ODP sites 950-952 in the Madeira Abyssal Plain. Processed thickness values correspond to a maximum thickness of about 1450 m and an average thickness of more than 500 m based on velocity data from ODP sites 950-952. The structure of the surveyed area and its location in relation to the Madeira Abyssal Plain and Mid-Atlantic Ridge indicate the existence, south of Azores, of two distinct sedimentary basins separated by major structural lineaments (Azores-Gibraltar and Atlantis Fracture Zones) and by seamount chains (Cruiser-Great Meteor Chain, Plato-Atlantis Chain). The basement of the sedimentary basins is irregular, showing multiple dome-shaped volcanic structures identical to those in the Norwegian-Greenland Sea and Madeira Abyssal Plain. However, half-graben/graben basement blocks predominate east of 30ºW underneath a moderately deformed overburden. The complex structure observed most likely reflects changes in the direction and velocity of ocean spreading plus variations in the regional thermal gradients induced by local hot spots. In parallel, some of the sub-surface structures identified next to basin-bounding Fracture Zones may have resulted from transtensional and transpressional tectonism.

  7. 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

  8. Chrysobrycon eliasi, new species of stevardiine fish (Characiformes: Characidae from the río Madre de Dios and upper río Manuripe basins, Peru

    Directory of Open Access Journals (Sweden)

    James Anyelo Vanegas-Ríos

    Full Text Available Chrysobrycon eliasi is described from several drainages of río Madre de Dios and upper río Manuripe basins, río Madeira basin, Peru. The new species is distinguished from its congeners by the maxillary teeth, which are tricuspidate, bicuspidate and conical, and the terminal lateral-line tube developed between caudal-fin rays 10-11. Other characters that help to recognize C. eliasi are the possession of maxilla with 6-15 (usually 11 teeth occupying more than 70% of the length of the maxilla in adults, predorsal scales 18-22, dorsal-fin to hypural complex length 36.32-41.17% of standard length (SL, gill-gland length in males 3.57-5.05% SL, maxillary length 33.76-38.75% of head length, and branched anal-fin rays 24-30. The discovery of C. eliasi allows us to extend the geographic distribution of the genus to the southeast, into the río Madeira basin.

  9. MIDDLE TRIASSIC PLATFORM AND BASIN EVOLUTION OF THE SOUTHERN BAKONY MOUNTAINS (TRANSDANUBIAN RANGE, HUNGARY

    Directory of Open Access Journals (Sweden)

    TAMÁS BUDAI

    2006-11-01

    Full Text Available Middle Triassic history of the Southern Bakony Mts. is outlined on the base of horizontal and vertical facies changes of the formations. During the Pelsonian (Balatonicus Chron the evolution of the basins and platforms was determined basically by synsedimentary tectonics. The Felsõörs basin of the Balaton Highland opened due to the block-faulting of the Bithynian carbonate ramp (Megyehegy Dolomite. Above the drowning blocks „halfgraben” basins were formed (Felsõörs Formation, while isolated platforms developed on the uplifted ones in the middle part of the Balaton Highland and on the Veszprém plateau (Tagyon Formation. Due to the relative sea-level fall in the early Illyrian, the platforms became subaerially exposed and karstified. As a consequence of the late Illyrian tectonic subsidence (manifested by neptunian dykes the central platform of the Balaton Highland has been drowned (Camunum Subchron. On the contrary, the Anisian platform of the Veszprém plateau was totally flooded only during the latest Illyrian (Reitzi Subchron due to eustatic sea-level rise. It was followed by a short highstand period (Secedensis Chron, characterised by the first progradation of the Budaörs platform on the Veszprém plateau and highstand shedding in the basins and on the submarine high (Vászoly Limestone in the centre of the Balaton Highland basin. Due to the following rapid sea-level rise, carbonate sedimentation continued in eupelagic basin from the Fassanian (Buchenstein Formation. At the beginning of the late Longobardian highstand period (Regoledanus Chron the Budaörs platform intensively prograded from the Veszprém plateau to the southwest, causing highstand shedding in the Balaton Highland basin (Füred Limestone. 

  10. 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

  11. Paleobasin analysis and tectonic framework development of southern Zagros basin, interpreted from Landsat 4 thematic mapper image

    Energy Technology Data Exchange (ETDEWEB)

    Iranpanah, A.

    1986-05-01

    Detailed lineament maps produced with the digitally enhanced Landsat 4 thematic mapper in conjunction with field data provide new information on structural relations to the southern Zagros basin. Three major parallel lineaments are from north to south, Qatar-Kazern, Razak, and Oman. These lineaments trend approximately N17/sup 0/E and subdivide the Zagros basin into northern, central, and southern segments. The study area is enclosed by the Razak and Oman lineaments. Piercement salt domes (Precambrian salt) are abundant within the southern Zagros basin, absent east of the Oman lineament, and scarce in the area west of the Razak lineament. This salt dome distribution and the N17/sup 0/E trend suggest that these lineaments are surface manifestations of boundaries of basement crustal blocks that have been reactivated periodically since the Precambrian. The northern extension of this Precambrian basin is marked by salt domes (Precambrian salt) along the Oman lineament, located in the Kerman region 400 km north of Minab. Along the eastern boundary, at the juncture of the southern Zagros basin and western Makran Ranges, the trend of fold axes changes from east-west to north-south. The western basin boundary is characterized by a gradual change in the trend of the fold axis from east-west to northwest-southeast. This study provides useful information for subsurface interpretations, which will benefit hydrocarbon exploration. The Razak and Oman lineaments enclose a highly productive area, and separate the southern Zagros basin from less productive areas to the west and from a nonproductive region to the east where chromite and iron deposits are common. These findings suggest that lineaments may serve as an exploration guide for hydrocarbons and economic mineral deposits, and as a model for developing the tectonic framework of the southern Zagros basin.

  12. Study of southern CHAONAN sag lower continental slope basin deposition character in Northern South China Sea

    Science.gov (United States)

    Tang, Y.

    2009-12-01

    Northern South China Sea Margin locates in Eurasian plate,Indian-Australia plate,Pacific Plates.The South China Sea had underwent a complicated tectonic evolution in Cenozoic.During rifting,the continental shelf and slope forms a series of Cenozoic sedimentary basins,including Qiongdongnan basin,Pearl River Mouth basin,Taixinan basin.These basins fill in thick Cenozoic fluviolacustrine facies,transitional facies,marine facies,abyssal facies sediment,recording the evolution history of South China Sea Margin rifting and ocean basin extending.The studies of tectonics and deposition of depression in the Southern Chaonan Sag of lower continental slope in the Norther South China Sea were dealt with,based on the sequence stratigraphy and depositional facies interpretation of seismic profiles acquired by cruises of“China and Germany Joint Study on Marine Geosciences in the South China Sea”and“The formation,evolution and key issues of important resources in China marginal sea",and combining with ODP 1148 cole and LW33-1-1 well.The free-air gravity anomaly of the break up of the continental and ocean appears comparatively low negative anomaly traps which extended in EW,it is the reflection of passive margin gravitational effect.Bouguer gravity anomaly is comparatively low which is gradient zone extended NE-SW.Magnetic anomaly lies in Magnetic Quiet Zone at the Northern Continental Margin of the South China Sea.The Cenozoic sediments of lower continental slope in Southern Chaonan Sag can be divided into five stratum interface:SB5.5,SB10.5,SB16.5,SB23.8 and Hg,their ages are of Pliocene-Quaternary,late Miocene,middle Miocene,early Miocene,paleogene.The tectonic evolution of low continental slope depressions can be divided into rifting,rifting-depression transitional and depression stages,while their depositional environments change from river to shallow marine and abyssa1,which results in different topography in different stages.The topographic evolvement in the study

  13. 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…

  14. 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.

  15. Techniques of DNA-studies on prehispanic ectoparasites (Pulex sp., Pulicidae, Siphonaptera from animal mummies of the Chiribaya Culture, Southern Peru

    Directory of Open Access Journals (Sweden)

    K Dittmar

    2003-01-01

    Full Text Available During a paleoparasitological survey of several animal mummies (Cavia aperea f. porcellus and Canis familiaris from Chiribaya Baja, an archaeological site in Southern Peru, an unexpected find was made. In the well preserved fur, large numbers of mummified fleas (Pulex simulans/irritansthat parasitized the animals during life were encountered. Due to the relative recent event of the host mummification and the outstanding preservation of the fleas, an attempt for the retrieval of DNA was made. A DNA extraction and sequencing protocol for archaeological ectoparasitic remains has been established, taking additional studies for tissue and protein preservation into account. Tissue preservation was assessed with transmission electron microscopy and the protein preservation was tested through the racemisation ratios of aspartic acid. Regions of the 28S rDNA gene were successfully amplified and sequenced. Further research perspectives are outlined.

  16. Molluscs as evidence for a late Pleistocene and early Holocene humid period in the southern coastal desert of Peru (14.5°S)

    Science.gov (United States)

    Mächtle, Bertil; Unkel, Ingmar; Eitel, Bernhard; Kromer, Bernd; Schiegl, Solveig

    2010-01-01

    The southern Peruvian coastal desert around Palpa, southern Peru (14.5°S) is currently characterized by hyper-arid conditions. However, the presence of two species of molluscs ( Scutalus, Pupoides) and desert-loess deposits indicates the past development of semi-desert and grassland ecosystems caused by a displacement of the eastern desert margin due to hydrological changes. Radiocarbon dating shows that the transition to a semi-arid climate in the southern Peruvian coastal desert took place during the Greenland interstadial 1, ˜ 13.5 cal ka BP. At the beginning of the Holocene, the mollusc fauna vanished due to increasing humidity and the development of grasslands. Dust particles were fixed by the grasses, as indicated by abundant Poaceae phytoliths, and desert loess was formed. The humid period we observe here is out of phase with the palaeoenvironmental records from the Titicaca region, which indicates dry conditions at that time. This paper offers a new idea for this contradiction: an orbitally driven meridional shift of the Bolivian high might have altered the moisture supply across the Andes.

  17. The Frasnian-Famennian boundary (Upper Devonian) in black shale sequences: US Southern Midcontinent, Illinois Basin, and northern Appalachian Basin

    Energy Technology Data Exchange (ETDEWEB)

    Over, D.J. (State Univ. of New York, Geneseo, NY (United States). Dept. of Geological Sciences)

    1994-04-01

    The Frasnian-Famennian (F/F) boundary in the Woodford Shale of the US southern Midcontinent, Sweetland Creek Shale of the Illinois Basin, and the Hanover Shale of the northern Appalachian Basin is recognized to a discrete horizon. In each locality the boundary is marked by evidence of a disconformity: phosphate nodules, concentration of conodonts, or coated and corroded grains. The Woodford Shale consists of finely laminated pyritic organic-rich shale containing interbeds of greenish shale and chert. The F/F boundary horizon is marked by a concentration of conodonts and phosphatic nodules. The boundary lag horizon contains Pa. linguliformis, Pa. subperlobtata, Pa. delicatula delicatula, and Pa. triangularis. Underlying laminations contain Ancyrognathus ubiquitus and Pa. triangularis indicating that the disconformity is within the uppermost MN Zone 13 or Lower triangularis Zone. The upper portion of the Type Sweetland Creek Shale consists of dark organic-rich shales. The F/F boundary is located within an interval containing three green shale interbeds. Palmatolepis triangularis in the absence of Frasnian species first occurs in the middle green shale. In the thick Upper Devonian clastic sequence of the northern Appalachian Basin the F/F boundary is within an interval of interbedded pyritic green and organic-rich silty shales of the Hanover Shale. At Irish Gulf strata containing Pa. triangularis overlie finely laminated dark shales containing Pa. bogartensis, Pa. triangularis, Pa. winchell, Ancyrodella curvata, and Icriodus alternatus. The conodont fauna transition is below a conodont-rich laminae containing a Famennian fauna that marks the boundary horizon.

  18. 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

  19. Pre-Columbian population dynamics in coastal southern Peru: A diachronic investigation of mtDNA patterns in the Palpa region by ancient DNA analysis.

    Science.gov (United States)

    Fehren-Schmitz, Lars; Reindel, Markus; Cagigao, Elsa Tomasto; Hummel, Susanne; Herrmann, Bernd

    2010-02-01

    Alternative models have been proposed to explain the formation and decline of the south Peruvian Nasca culture, ranging from migration or invasion to autochthonous development and ecological crisis. To reveal to what extent population dynamic processes accounted for cultural development in the Nasca mainland, or were influenced by them, we analyzed ancient mitochondrial DNA of 218 individuals, originating from chronologically successive archaeological sites in the Palpa region, the Paracas Peninsula, and the Andean highlands in southern Peru. The sampling strategy allowed a diachronic analysis in a time frame from approximately 800 BC to 800 AD. Mitochondrial coding region polymorphisms were successfully analyzed and replicated for 130 individuals and control region sequences (np 16021-16408) for 104 individuals to determine Native American mitochondrial DNA haplogroups and haplotypes. The results were compared with ancient and contemporary Peruvian populations to reveal genetic relations of the archaeological samples. Frequency data and statistics show clear proximity of the Nasca populations to the populations of the preceding Paracas culture from Palpa and the Peninsula, and suggest, along with archaeological data, that the Nasca culture developed autochthonously in the Rio Grande drainage. Furthermore, the influence of changes in socioeconomic complexity in the Palpa area on the genetic diversity of the local population could be observed. In all, a strong genetic affinity between pre-Columbian coastal populations from southern Peru could be determined, together with a significant differentiation from ancient highland and all present-day Peruvian reference populations, best shown in the differential distribution of mitochondrial haplogroups. 2009 Wiley-Liss, Inc.

  20. TRANSGRESSIVE SEQUENCES ON FORELAND MARGINS: A CASE STUDY OF THE NEOGENE CENTRAL GUADALQUIVIR BASIN, SOUTHERN SPAIN

    Directory of Open Access Journals (Sweden)

    J. GABRIEL PENDÓN

    2004-07-01

    Full Text Available The Guadalquivir foreland basin, located between the Iberian basement northward and the Betic orogen to the South, represents the western sector of the earlier foredeep basin of the Betic Cordillera. Along the northern foreland margin, the sedimentary fill of this basin includes a Tortonian Basal Transgressive Complex (BTC, composed of five internal sequences bounded by transgressive surfaces. Two main parts are distinguished within each sequence: the lower transgressive lag deposits, and the upper stillstand/prograding sediments. Three facies associations were distinguished within this stratigraphic succession along the central sector of this basin margin: unfossiliferous conglomerates and coarse-grained sands (A, fossiliferous conglomerates and coarse-grained sands (B, and yellow medium-coarse-grained fossiliferous sands (C. A fourth facies association (D: blue silty marlstones and shales overlies the BTC. Deposits of alluvial sediments (facies association A and shallow-marine/foreshore sediments (facies association C, were recurrently interrupted by transgressive pulses (facies associations B and C. Every pulse is recorded by an erosional, cemented sandy-conglomerate bar with bivalves (Ostreidae, Isognomon, balanids, gastropods and other marine bioclasts; or their transgressive equivalents. The lateral facies changes in each individual sequence of the BTC are related to: (1 the influence on the northern foreland margin of the tectonic activity of the southern orogenic margin; (2 the palaeorelief formed by irregularities of the substrate which controls the sediment dispersal; and (3 the evolution stages of the sedimentary systems. 

  1. Chemical characteristics of Central Indian Basin waters during the southern summer

    Digital Repository Service at National Institute of Oceanography (India)

    DeSousa, S.N.; Sardessai, S.; RameshBabu, V.; Murty, V.S.N.; Gupta, G.V.M.

    aspects of oxygen deficient conditions and denitrification in the Arabian Sea. Journal of MarineResearch 45,1049–1072. Redfield,A.C.,Ketchum,B.H.,Richards,F.A.,1963.Theinfluenceoforganismsonthecompositionofseawater.In: Hill, M.N. (Ed.), The Sea: Ideas...-Sea Research II 48 (2001)3343–3352 Chemical characteristics of Central Indian Basin waters during the southern summer S.N. de Sousa*,S.D. Sardessai, V. Ramesh Babu, V.S.N. Murty, G.V.M. Gupta NationalInstituteofOceanography,DonaPaula,Goa403004,India Abstract...

  2. A new species of Ituglanis (Siluriformes: Trichomycteridae from the rio Uruguai basin, southern Brazil

    Directory of Open Access Journals (Sweden)

    Juliano Ferrer

    2017-10-01

    Full Text Available ABSTRACT A new species of Ituglanis associated to the grasslands of the Pampa biome is described from the rio Uruguai basin, southern Brazil. The new species is distinguished from its congeners by the low number of ribs and by a unique color pattern composed of an outer layer with scattered round black blotches equivalent in size to the eye circumference over a reddish brown background on the lateral surface of the body. We provide the genetic sequences of the mitochondrial gene Cytochrome c Oxydase subunit I (COI for three of the paratypes and discuss aspects about the recent discovery of the new species.

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

    Science.gov (United States)

    Hollingsworth, Jeffery L.

    2016-01-01

    ' 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.

  4. Study on integrated evaluation of sandstone-hosted uranium metallogenic potential in southern Yili basin

    International Nuclear Information System (INIS)

    Han Shaoyang; Ke Dan; Xu Jianguo; Zheng Enjiu; Li Shengxiang

    2008-01-01

    Plenty of geological data have been accumulated during mineral resource survey in China; under the guidance of new metallogenic theories, it is an important task of how to use these data most effectively for the new cycle uranium survey. In this paper, the flow of establishing the integrated mineral deposits prospecting model for sandstone-hosted uranium deposits is put forward. Based on studying geologic, hydrogeologic and regional geophysical field characteristics of representative uranium deposits No. 512 in southern Yili basin, its multi-source information descriptive model has been established, from which 512-type integrated prospecting models of sandstone-hosted uranium orefield and deposits are summarized. According to the established integrated prospecting models, the metallogenic information extraction of sandstone-hosted uranium deposits has completed in the study area. Finally, the integrated quantitative evaluation of sandstone-hosted uranium metallogenic potential is performed by using the evidence weighing method to integrate middle scale multi-source metallogenic information in the southern Yili basin, and good prediction effect is obtained. (authors)

  5. Principal facts for gravity data collected in the southern Albuquerque Basin area and a regional compilation, central New Mexico

    Science.gov (United States)

    Gillespie, Cindy L.; Grauch, V.J.S.; Oshetski, Kim; Keller, Gordon R.

    2000-01-01

    Principal facts for 156 new gravity stations in the southern Albuquerque basin are presented. These data fill a gap in existing data coverage. The compilation of the new data and two existing data sets into a regional data set of 5562 stations that cover the Albuquerque basin and vicinity is also described. Bouguer anomaly and isostatic residual gravity data for this regional compilation are available in digital form from ftp://greenwood.cr.usgs.gov/pub/openfile- reports/ofr-00-490.

  6. 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

  7. Pore characteristics of shale gas reservoirs from the Lower Paleozoic in the southern Sichuan Basin, China

    Directory of Open Access Journals (Sweden)

    Xianqing Li

    2016-06-01

    Full Text Available Data was acquired from both the drillings and core samples of the Lower Paleozoic Qiongzhusi and Longmaxi Formations' marine shale gas reservoirs in the southern Sichuan Basin by means of numerous specific experimental methods such as organic geochemistry, organic petrology, and pore analyses. Findings helped determine the characteristics of organic matter, total porosity, microscopic pore, and pore structure. The results show that the Lower Paleozoic marine shale in the south of the Sichuan Basin are characterized by high total organic carbon content (most TOC>2.0%, high thermal maturity level (RO = 2.3%–3.8%, and low total porosity (1.16%–6.87%. The total organic carbon content and thermal maturity level of the Qiongzhusi Formation shale are higher than those of the Longmaxi Formation shale, while the total porosity of the Qiongzhusi Formation shale is lower than that of the Longmaxi Formation shale. There exists intergranular pore, dissolved pore, crystal particle pore, particle edge pore, and organic matter pore in the Lower Paleozoic Qiongzhusi Formation and Longmaxi Formation shale. There are more micro-nano pores developed in the Longmaxi Formation shales than those in the Qiongzhusi Formation shales. Intergranular pores, dissolved pores, as well as organic matter pores, are the most abundant, these are primary storage spaces for shale gas. The microscopic pores in the Lower Paleozoic shales are mainly composed of micropores, mesopores, and a small amount of macropores. The micropore and mesopore in the Qiongzhusi Formation shale account for 83.92% of the total pore volume. The micropore and mesopore in the Longmaxi Formation shale accounts for 78.17% of the total pore volume. Thus, the micropores and mesopores are the chief components of microscopic pores in the Lower Paleozoic shale gas reservoirs in the southern Sichuan Basin.

  8. 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.

  9. Availability of ground water in the middle Merrimack River basin, central and southern New Hampshire

    Science.gov (United States)

    Cotton, J.E.

    1976-01-01

    Sufficient amounts of water to supply single family homes are available from the bedrock aquifer nearly everywhere in the middle Merrimack River basin in central and southern New Hampshire. Relatively this and narrow, unconsolidated aquifers of sand or sand and gravel commonly capable of yielding more than 200 gallons per minute to properly located and constructed wells are found only in major stream valleys. The map provides a preliminary assessment of the availability of ground water in the basin, as determined by estimating the capability of the aquifers to store and transmit water. On the map, aquifers are rated as having high, medium, or low potential to yield water. Ground water in the middle Merrimack River basin is generally of good chemical quality. Most of it is clear and colorless, contains no suspended matter and practically no bacteria, water may be affected by land-use practices. Degradation of water quality may occur in unsewered residential and village areas, near solid-waste-disposal sites, agricultural land, and major highways. (Woodard-USGS)

  10. Soft sediment deformation structures in the Maastrichtian Ajali Formation Western Flank of Anambra Basin, Southern Nigeria

    Science.gov (United States)

    Olabode, Solomon Ojo

    2014-01-01

    Soft sediment deformation structures were recognized in the Maastrichtian shallow marine wave to tide influenced regressive sediments of Ajali Formation in the western flank of Anambra basin, southern Nigerian. The soft sediment deformation structures were in association with cross bedded sands, clay and silt and show different morphological types. Two main types recognised are plastic deformations represented by different types of recumbent folds and injection structure represented by clastic dykes. Other structures in association with the plastic deformation structures include distorted convolute lamination, subsidence lobes, pillars, cusps and sand balls. These structures are interpreted to have been formed by liquefaction and fluidization mechanisms. The driving forces inferred include gravitational instabilities and hydraulic processes. Facies analysis, detailed morphologic study of the soft sediment deformation structures and previous tectonic history of the basin indicate that the main trigger agent for deformation is earthquake shock. The soft sediment deformation structures recognised in the western part of Anambra basin provide a continuous record of the tectonic processes that acted on the regressive Ajali Formation during the Maastrichtian.

  11. The deeper structure of the southern Dead Sea basin derived from neural network analysis of velocity and attenuation tomography

    Science.gov (United States)

    Braeuer, Benjamin; Haberland, Christian; Bauer, Klaus; Weber, Michael

    2014-05-01

    The Dead Sea basin is a pull-apart basin at the Dead Sea transform fault, the boundary between the African and the Arabian plates. Though the DSB has been studied for a long time, the available knowledge - based mainly on surface geology, drilling and seismic reflection surveys - gives only a partial picture of its shallow structure. Therefore, within the framework of the international DESIRE (DEad Sea Integrated REsearch) project, a dense temporary local seismological network was operated in the southern Dead Sea area. Within 18 month of recording 650 events were detected. In addition to an already published tomography study revealing the distribution of P velocities and the Vp/Vs ratios a 2D P-wave attenuation tomography (parameter Qp) was performed. The neural network technique of Self-organizing maps (SOM) is used for the joint interpretation of these three parameters (Vp, Vp/Vs, Qp). The resulting clusters in the petrophysical parameter space are assigned to the main lithological units below the southern part of the Dead Sea basin: (1) The basin sediments characterized by strong attenuation, high vp/vs ratios and low P velocities. (2) The pre-basin sediments characterized by medium to strong attenuation, low Vp/Vs ratios and medium P velocities. (3) The basement characterized by low to moderate attenuation, medium vp/vs ratios and high P velocities. Thus, the asymmetric southern Dead Sea basin is filled with basin sediments down to depth of 7 to 12 km. Below the basin sediments, the pre-basin sediments are extending to a depth between 13 and 18 km.

  12. Geomorphic evolution of the San Luis Basin and Rio Grande in southern Colorado and northern New Mexico

    Science.gov (United States)

    Ruleman, Chester A.; Machette, Michael; Thompson, Ren A.; Miggins, Dan M; Goehring, Brent M; Paces, James B.

    2016-01-01

    The San Luis Basin encompasses the largest structural and hydrologic basin of the Rio Grande rift. On this field trip, we will examine the timing of transition of the San Luis Basin from hydrologically closed, aggrading subbasins to a continuous fluvial system that eroded the basin, formed the Rio Grande gorge, and ultimately, integrated the Rio Grande from Colorado to the Gulf of Mexico. Waning Pleistocene neotectonic activity and onset of major glacial episodes, in particular Marine Isotope Stages 11–2 (~420–14 ka), induced basin fill, spillover, and erosion of the southern San Luis Basin. The combined use of new geologic mapping, fluvial geomorphology, reinterpreted surficial geology of the Taos Plateau, pedogenic relative dating studies, 3He surface exposure dating of basalts, and U-series dating of pedogenic carbonate supports a sequence of events wherein pluvial Lake Alamosa in the northern San Luis Basin overflowed, and began to drain to the south across the closed Sunshine Valley–Costilla Plain region ≤400 ka. By ~200 ka, erosion had cut through topographic highs at Ute Mountain and the Red River fault zone, and began deep-canyon incision across the southern San Luis Basin. Previous studies indicate that prior to 200 ka, the present Rio Grande terminated into a large bolson complex in the vicinity of El Paso, Texas, and systematic, headward erosional processes had subtly integrated discontinuously connected basins along the eastern flank of the Rio Grande rift and southern Rocky Mountains. We propose that the integration of the entire San Luis Basin into the Rio Grande drainage system (~400–200 ka) was the critical event in the formation of the modern Rio Grande, integrating hinterland basins of the Rio Grande rift from El Paso, Texas, north to the San Luis Basin with the Gulf of Mexico. This event dramatically affected basins southeast of El Paso, Texas, across the Chisos Mountains and southeastern Basin and Range province, including the Rio

  13. The geometry of pull-apart basins in the southern part of Sumatran strike-slip fault zone

    Science.gov (United States)

    Aribowo, Sonny

    2018-02-01

    Models of pull-apart basin geometry have been described by many previous studies in a variety tectonic setting. 2D geometry of Ranau Lake represents a pull-apart basin in the Sumatran Fault Zone. However, there are unclear geomorphic traces of two sub-parallel overlapping strike-slip faults in the boundary of the lake. Nonetheless, clear geomorphic traces that parallel to Kumering Segment of the Sumatran Fault are considered as inactive faults in the southern side of the lake. I demonstrate the angular characteristics of the Ranau Lake and Suoh complex pull-apart basins and compare with pull-apart basin examples from published studies. I use digital elevation model (DEM) image to sketch the shape of the depression of Ranau Lake and Suoh Valley and measure 2D geometry of pull-apart basins. This study shows that Ranau Lake is not a pull-apart basin, and the pull-apart basin is actually located in the eastern side of the lake. Since there is a clear connection between pull-apart basin and volcanic activity in Sumatra, I also predict that the unclear trace of the pull-apart basin near Ranau Lake may be covered by Ranau Caldera and Seminung volcanic products.

  14. Nd, Sr-isotopic provenance and trace element geochemistry of Amazonian foreland basin fluvial sands, Bolivia and Peru: Implications for ensialic Andean orogeny

    International Nuclear Information System (INIS)

    Basu, A.R.; Sharma, M.; DeCelles, P.G.

    1990-01-01

    Nd and Sr isotopes and the trace element contents, including the rare earths, were determined for fluvial sands of lithic arenite composition from the Madre de Dios foreland basin of Bolivia and Peru. On standard petrologic ternary diagrams, the sands fall in the recycled orogen provenance field and thus are similar to typical ancient foreland basin composition. The average rare earth elemental pattern of the sands is identical to the upper continental crustal average, as estimated from post-Archean composite shales of different continents. Ratio of Th/U, Co/Th, La/Sc and Th/Sc of the fluvial sands are intermediate between an average magmatic arc and an upper crustal average compositions. The dispersion of some trace elemental patterns in the sands can be attributed to fractionation of dense minerals, including zircon, during the sedimentation process. The variations of Nd isotopes in conjunction with the petrographic parameters of lithic metamorphic (Lm) and volcanic (Lv) fragments allow a two-fold classification of the sands. These two sand types can be interpreted in terms of mixing among three different provenances: one volcanic rock-suit with less negative ε Nd (O) parameter than the other volcanic suite, and a third metasedimentary source with ε Nd (O) value of around -12, which is considered to be similar to the average western Brazilian shield composition. Thus the overall compositions of the sands has been modeled as mechanical mixtures of two components, an Andean magmatic arc and the Brazilian shield-derived metasediments. The model is strongly supported by a plot of ε Nd (O) versus ε Sr (O) of the sands. In this plot, the Type 1 and 2 sands define two coherent hyperbolic trends contiguous with two different portions of the Andean magmatic trend. (orig./WB)

  15. Clarifying regional hydrologic controls of the Marañón River, Peru through rapid assessment to inform system-wide basin planning approaches

    Directory of Open Access Journals (Sweden)

    Alice F. Hill

    2018-04-01

    Full Text Available We use remote sensing to enhance the interpretation of the first baseline dataset of hydrologic, isotopic and hydrochemical variables spanning 620 km of the upper Marañón River, in Andean Peru, from the steep alpine canyons to the lower lying jungle. Remote, data-scarce river systems are under increased hydropower development pressure to meet rising energy demands. The upstream-downstream river continuum, which serves as a conduit for resource exchange across ecosystems, is at risk, potentially endangering the people, environments, and economies that rely on river resources. The Marañón River, one of the final free-flowing headwater connections between the Andes and the Amazon, is the subject of myriad large-scale hydropower proposals. Due to challenging access, environmental data are scarce in the upper Marañón, limiting our ability to do system-wide river basin planning. We capture key processes and transitions in the context of hydropower development. Two hydrologic regimes control the Marañón dry-season flow: in the higher-elevation upper reaches, a substantial baseflow is fed by groundwater recharged from wet season rains, in contrast to the lower reaches where the mainstem discharge is controlled by rain-fed tributaries that receive rain from lowland Amazon moisture systems. Sustainability of the upper corridor’s dry-season baseflow appears to be more highly connected to the massive natural storage capacity of extensive wetlands in the puna (alpine grasslands than with cryospheric water inputs. The extent and conservation of puna ecosystems and glacier reservoirs may be interdependent, bringing to bear important conservation questions in the context of changing climate and land use in the region. More generally, this case study demonstrates an efficient combined remote sensing and field observation approach to address data scarcity across regional scales in mountain basins facing imminent rapid change.

  16. Peculiarities of the hydrological regime of the fishery water reservoirs at the basin of the Southern Bug of Vinnytsia region

    OpenAIRE

    V. Baban; I. Gamaliy.

    2014-01-01

    This paper deals with analysis of hydrological regime of the fishery water reservoirs at the basin of the Southern Bug of Vinnytsia region. Systematization of the investigated water bodies was performed by the authors on the basis of previously developed classification and typing of water reservoirs.

  17. Sedimentological and mineralogical characteristics of recent sediments at selected sites in the southern basin of Lake Michigan

    International Nuclear Information System (INIS)

    Tisue, G.T.; Merk, G.

    1976-01-01

    During the 1976 field season, sediment traps and current meters were set out in the southern basin of Lake Michigan to study the relationship between suspended material and currents. The gross mineralogical and chemical characteristics of the bottom sediments at the locations of these experiments were determined

  18. Effects of uranium development on erosion and associated sedimentation in southern San Juan Basin, New Mexico

    Science.gov (United States)

    Cooley, Maurice E.

    1979-01-01

    A reconnaissance was made of some of the effects of uranium development on erosion and associated sedimentation in the southern San Juan Basin, where uranium development is concentrated. In general, the effects of exploration on erosion are minor, although erosion may be accelerated by the building of access roads, by activities at the drilling sites, and by close concentration of drilling sites. Areas where the greatest effects on erosion and sedimentation from mining and milling operations have occurred are: (1) in the immediate vicinity of mines and mills, (2) near waste piles, and (3) in stream channels where modifications, such as changes in depth have been caused by discharge of excess mine and mill water. Collapse of tailings piles could result in localized but excessive erosion and sedimentation.

  19. Influences of structures on the interlayer oxidation zone sandstone-type uranium deposits on the southern margin of Yili basin

    International Nuclear Information System (INIS)

    Wang Mou; Li Shengfu

    2006-01-01

    Based on geology and the theory of hydromorphic origin uranium deposit, structural conditions of uranium formation on the southern margin of Yili Basin are analyzed from two aspects of structural movements and deformation. It is suggested that the subsidiary structures caused by the neotectonic movement are the major factor that control and reform the interlayer oxidation zone sandstone-type uranium deposit, and the differences lie in the tectonics at the eastern and western section on the southern margin of Yili Basin. At the western section, because Mesozoic and Cenozoic strata are tilted by the subsidiary structures, some strata on the margin of the basin outcrop at the surface and suffer from the weathering and erosion, which is favorable for the formation of large size uranium deposits. But at the eastern section, the fault and fold are predominant, outcropping at the surface, cause the redistribution of the uranium, which is favorable for the formation of small size uranium deposits. (authors)

  20. Neotectonic movement and its relation to uranium metallogenesis in central-southern Songliao basin and its adjacent areas

    International Nuclear Information System (INIS)

    Sang Jisheng; Zhang Yongbao; Chen Weiyi

    2004-01-01

    The central-southern Songliao basin and its adjacent area ar located in the south of Inner Mongolian-Northeastern China neotectonic region of the circum-pacific neotectonic domain. Since Late Tertiary the neotectonic movement in the region has been being more intense, and the most obvious feature of the neotectonic movement was characterized by large-amplitude block-faulting and strong volcanic activity. The mega-scale basin-and-range tectonics and other micro-geomorphology created favourable tectonic and geomorphologic conditions for the ore-formation of in-situ leachable sandstone-type uranium deposits. Neotectonic movement played both positive and negative roles in uranium ore-formation. Neotectonics are well developed at the eastern and the southern margins of the Songliao basin, and these areas are favourable for locating in-situ leachable sandstone-type uranium deposits

  1. Late Quaternary faulting in the Vallo di Diano basin (southern Apennines, Italy)

    Science.gov (United States)

    Villani, F.; Pierdominici, S.; Cinti, F. R.

    2009-12-01

    The Vallo di Diano is the largest Quaternary extensional basin in the southern Apennines thrust-belt axis (Italy). This portion of the chain is highly seismic and is currently subject to NE-extension, which triggers large (M> 6) normal-faulting earthquakes along NW-trending faults. The eastern edge of the Vallo di Diano basin is bounded by an extensional fault system featuring three main NW-trending, SW-dipping, right-stepping, ~15-17 km long segments (from north to south: Polla, Atena Lucana-Sala Consilina and Padula faults). Holocene activity has been documented so far only for the Polla segment. We have therefore focused our geomorphological and paleoseismological study on the southern portion of the system, particularly along the ~ 4 km long Atena Lucana-Sala Consilina and Padula faults overlap zone. The latter is characterized by a complex system of coalescent alluvial fans, Middle Pleistocene to Holocene in age. Here we recognized a > 4 km long and 0.5-1.4 km wide set of scarps (ranging in height between 1 m and 2.5 m) affecting Late Pleistocene - Holocene alluvial fans. In the same area, two Late Pleistocene volcanoclastic layers at the top of an alluvial fan exposed in a quarry are affected by ~ 1 m normal displacements. Moreover, a trench excavated across a 2 m high scarp affecting a Holocene fan revealed warping of Late Holocene debris flow deposits, with a total vertical throw of about 0.3 m. We therefore infer the overlap zone of the Atena Lucana-Sala Consilina and Padula faults is a breached relay ramp, generated by hard-linkage of the two fault segments since Late Pleistocene. This ~ 32 km long fault system is active and is capable of generating Mw ≥6.5 earthquakes.

  2. A Thermal Maturity Analysis of the Effective Cretaceous Petroleum System in the Southern Persian Gulf Basin

    Directory of Open Access Journals (Sweden)

    Majid Alipour

    2017-10-01

    Full Text Available Commercial hydrocarbon discoveries in the Cretaceous of the southern Persian Gulf basin provide direct evidence that there is an effective petroleum system associated with the Cretaceous series. The revised models of thermal maturity in this region are needed to investigate lateral and stratigraphic variations of thermal maturity, which have not so far been addressed in detail for this part of the Persian Gulf. Such thermal maturity models are required to delineate the existing play assessment risks and to predict properties in more deeply buried undrilled sections. This study uses two dimensional basin modeling techniques to reconstruct maturity evolution of the Cenomanian Middle Sarvak source rock, presumably the most likely source for these hydrocarbons. The results indicate that an estimated 900 meter difference in the depth of burial between the southeastern high and the adjacent trough tends to be translated into noticeable variations at both temperature (135 °C versus 162 °C and vitrinite reflectance (0.91% versus 1.35%. Since the organic matter in the mentioned source rock is of reactive type II, these could cause a shift of about 18 million years in the onset of hydrocarbon generation over respective areas.

  3. 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.

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

    Science.gov (United States)

    Wu, Yiping; Chen, Ji

    2012-12-15

    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. Published by Elsevier B.V.

  5. Biostratigraphy of a Paleocene–Eocene Foreland Basin boundary in southern Tibet

    Directory of Open Access Journals (Sweden)

    Xiaoqiao Wan

    2010-10-01

    Full Text Available 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.

  6. 40Ar/39Ar geochronology of hypabyssal igneous rocks in the Maranon Basin of Peru - A record of thermal history, structure, and alteration

    Science.gov (United States)

    Prueher, L.M.; Erlich, R.; Snee, L.W.

    2005-01-01

    Hypabyssal andesites and dacites from the Balsapuerto Dome in the Mara?on Basin of Peru record the thermal, tectonic, and alteration history of the area. The Mara?on Basin is one of 19 sub-Andean foreland basins. The hypabyssal rocks in the Balsapuerto Dome are one of four known occurrences of subvolcanic rocks along the deformation front in Peru. This dome is a potential petroleum structural trap. Petroleum seeps near the dome indicate that a source for the petroleum is present, but the extent and amount of petroleum development is unknown. The Balsapuerto hypabyssal rocks are plagioclase-, hornblende-, pyroxene-phyric andesites to dacites. Some parts of the dome are pervasively altered to a hydrothermal assemblage of quartz-sericite-pyrite. 40Ar/39Ar geochronology shows that thermal activity related to emplacement of these subvolcanic rocks took place between 12-10 Ma, subsequent to the major periods of Andean folding and faulting, previously assumed to have occurred about 9 Ma. Eleven argon mineral age-spectrum analyses were completed. Argon apparent ages on amphibole range from 12.7 to 11.6 Ma, and the age spectra are simple, which indicates that the ages are very close to emplacement ages. Potassium feldspar yields an argon age spectrum ranging in age from 12.5 to 11.4 Ma, reflecting the period during which the potassium feldspar closed to argon diffusion between the temperature range of 350?C to about 150?C; thus the potassium feldspar age spectrum reflects a cooling profile throughout this temperature range. This age range is consistent with ages of emplacement for the entire igneous complex indicating that an increased thermal state existed in the area for at least 1.0 m.y. Combined with the coexisting hornblende age, this rock cooled from ~580?C to ~150?C in ~1.2 m.y. resulting in an average cooling rate of 358?C /m.y. White mica, or sericite, formed as a later alteration phase associated with quartz- sericite- pyrite and propylitic alteration in some

  7. Hyperspectral remote sensing applied to mineral exploration in southern Peru: A multiple data integration approach in the Chapi Chiara gold prospect

    Science.gov (United States)

    Carrino, Thais Andressa; Crósta, Alvaro Penteado; Toledo, Catarina Labouré Bemfica; Silva, Adalene Moreira

    2018-02-01

    Remote sensing is a strategic key tool for mineral exploration, due to its capacity of detecting hydrothermal alteration minerals or alteration mineral zones associated with different types of mineralization systems. A case study of an epithermal system located in southern Peru is presented, aimed at the characterization of mineral assemblies for discriminating potential high sulfidation epithermal targets, using hyperspectral imagery integrated with petrography, XRD and magnetic data. HyMap images were processed using the Mixture Tuned Matched Filtering (MTMF) technique for producing alteration map in the Chapi Chiara epithermal gold prospect. Extensive areas marked by advanced argillic alteration (alunite-kaolinite-dickite ± topaz) were mapped in detail, as well as limited argillic (illite-smectite) and propylitic (chlorite spectral domain) alteration. The magmatic-hydrothermal processes responsible for the formation of hypogene minerals were also related to the destruction of ferrimagnetic minerals (e.g., magnetite) of host rocks such as andesite, and the remobilization/formation of paramagnetic Fe-Ti oxides (e.g., rutile, anatase). The large alteration zones of advanced argillic alteration are controlled by structures related to a regional NW-SE trend, and also by local NE-SW and ENE-WSW ones.

  8. Sedimentary facies analysis of the Mesozoic clastic rocks in Southern Peru (Tacna, 18°S): Towards a paleoenvironmental Redefinition and stratigraphic Reorganization

    Science.gov (United States)

    Alván, Aldo; Jacay, Javier; Caracciolo, Luca; Sánchez, Elvis; Trinidad, Inés

    2018-07-01

    The Mesozoic rocks of southern Peru comprise a Middle Jurassic to Early Cretaceous sedimentary sequence deposited during a time interval of approximately 34 Myr. In Tacna, these rocks are detrital and constitute the Yura Group (Callovian to Tithonian) and the Hualhuani Formation (Berriasian). Basing on robust interpretation of facies and petrographic analysis, we reconstruct the depositional settings of such units and provide a refined stratigraphic framework. Accordingly, nine types of sedimentary facies and six architectural elements are defined. They preserve the record of a progradational fluvial system, in which two styless regulated the dispersion of sediments: (i) a high-to moderate-sinuosity meandering setting (Yura Group), and a later (ii) incipient braided setting (Hualhuani Formation). The Yura Group (Callovian-Tithonian) represents the onset of floodplain deposits and lateral accretion of point-bar deposits sited on a semi-flat topography. Nonetheless, the progradational sequence was affected by at least two rapid marine ingressions occurred during Middle Callovian and Tithonian times. Such marine ingressions reveal the proximity of a shallow marine setting and incipient carbonate deposition. In response to increase in topographic gradient, the Hualhuani Formation (Berriasian) deposited as extensive multistory sandy channels. The mineralogy of the Mesozoic sediments suggests sediment supplies and intense recycling from a craton interior (i.e. Amazon Craton and/or plutonic sources) located eastward of the study area.

  9. 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

    2016-05-18

    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.

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

    Directory of Open Access Journals (Sweden)

    Shun-Li Li

    2014-04-01

    Full Text Available Junggar Basin, located in northern Xinjiang, presents continuous and multikilometer-thick strata of the Jurassic deposits. The Jurassic was entirely terrestrial fluvial and lacustrine deltaic sedimentation. Eight outcrop sections across the Jurassic strata were measured 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 palaeoclimate 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 Middle 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.

  11. A thick lens of fresh groundwater in the southern Lihue Basin, Kauai, Hawaii, USA

    Science.gov (United States)

    Izuka, Scot; Gingerich, Stephen

    2002-11-01

    A thick lens of fresh groundwater exists in a large region of low permeability in the southern Lihue Basin, Kauai, Hawaii, USA. The conventional conceptual model for groundwater occurrence in Hawaii and other shield-volcano islands does not account for such a thick freshwater lens. In the conventional conceptual model, the lava-flow accumulations of which most shield volcanoes are built form large regions of relatively high permeability and thin freshwater lenses. In the southern Lihue Basin, basin-filling lavas and sediments form a large region of low regional hydraulic conductivity, which, in the moist climate of the basin, is saturated nearly to the land surface and water tables are hundreds of meters above sea level within a few kilometers from the coast. Such high water levels in shield-volcano islands were previously thought to exist only under perched or dike-impounded conditions, but in the southern Lihue Basin, high water levels exist in an apparently dike-free, fully saturated aquifer. A new conceptual model of groundwater occurrence in shield-volcano islands is needed to explain conditions in the southern Lihue Basin. Résumé. Dans le sud du bassin de Lihue (Kauai, Hawaii, USA), il existe une épaisse lentille d'eau souterraine douce dans une vaste région à faible perméabilité. Le modèle conceptuel conventionnel pour la présence d'eau souterraine à Hawaii et dans les autres îles de volcans en bouclier ne rend pas compte d'une lentille d'eau douce si épaisse. Dans ce modèle conceptuel, les accumulations de lave dont sont formés la plupart des volcans en bouclier couvrent de vastes régions à relativement forte perméabilité, avec des lentilles d'eau douce peu épaisses. Dans le sud du bassin de Lihue, les laves remplissant le bassin et les sédiments constituent une région étendue à faible conductivité hydraulique régionale, qui, sous le climat humide du bassin, est saturée presque jusqu'à sa surface; les surfaces pi

  12. Two new species of Rineloricaria (Siluriformes: Loricariidae from the rio Iguaçu basin, southern Brazil

    Directory of Open Access Journals (Sweden)

    Leonardo F. S. Ingenito

    Full Text Available Rineloricaria langei and R. maacki, new species, are described from upper and middle regions of the rio Iguaçu basin, a left bank tributary of the rio Paraná basin, southern Brazil. Rineloricaria langei has narrow body and is similar to R. quadrensis, which is found in coastal rivers of Rio Grande do Sul State and is distinguishable by several morphometric characters. Rineloricaria maacki is distinguishable from all other congeners by the shape and extension of the naked area of the ventral region of pectoral girdle and other morphological characters. The presence of a naked region on the abdominal surface is shared with other species from the rio Paraná and rio Uruguay basins and coastal drainages from southeastern and southern Brazil. This may indicate a close phylogenetic relationship among these species. Similarities between the two new species and species from the aforementioned drainages also suggest close biogeographic relationship between the Paraná basin and other Brazilian coastal Atlantic drainages throughout the rio Iguaçu basin.

  13. 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

  14. 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

  15. New Insights into the Provenance of the Southern Junggar Basin in the Jurassic from Heavy Mineral Analysis and Sedimentary Characteristics

    Science.gov (United States)

    Zhou, T. Q.; Wu, C.; Zhu, W.

    2017-12-01

    Being a vital component of foreland basin of Central-western China, Southern Junggar Basin has observed solid evidences of oil and gas in recent years without a considerable advancement. The key reason behind this is the lack of systematic study on sedimentary provenance analysis of the Southern Junggar basin. Three parts of the Southern Junggar basin, including the western segment (Sikeshu Sag), the central segment (Qigu Fault-Fold Belt) and the eastern segment (Fukang Fault Zone), possess varied provenance systems, giving rise to difficulties for oil-gas exploration. In this study, 3468 heavy minerals data as well as the sedimentary environment analysis of 10 profiles and 7 boreholes were used to investigate the provenances of the deposits in the southern Junggar basin . Based on this research, it reveals that: Sikeshu sag initially shaped the foreland basin prototype in the Triassic and its provenance area of the sediments from the Sikeshu sag has primarily been situated in zhongguai uplift-chepaizi uplift depositional systems located in the northwestern margin of the Junggar Basin. From the early Jurassic, the key sources were likely to be late Carboniferous to early Permain post-collisional volcanic rocks from the North Tian Shan block to Centrao Tian Shan. In the Xishanyao formation, Abundant lithic metamorphic, epidote and garnet that suggests the source rocks were possibly late Carboniferous subduction-related arc volcanic rocks of the Central Tian Shan. In the Toutunhe formation, Bogda Mountains began uplifting and gradually becoming the major provenance. Moreover, the sedimentary boundaries of Junggar basin have also shifted towards the North Tian Shan again. In the late Jurassic, the conglomerates of the Kalazha formation directly overlie the fine-grained red beds of Qigu formation, which throw light on the rapid tectonic uplift of the North Tian Shan. In the eastern segment, meandering river delta and shore-lacustrine environments were fully developed

  16. The geochemistry of claystone-shale deposits from the Maastritchian Patti formation, Southern Bida basin, Nigeria

    Directory of Open Access Journals (Sweden)

    O Okunlola

    2012-07-01

    Full Text Available An inorganic geochemical study of a claystone and shale sequence from the Patti Formation around Ahoko in the Southern Bida basin, Nigeria, was carried out to determine the basin's depositional conditions,provenance and tectonics. Representative samples underwent mineralogical and geochemical analysis involving major, trace and rare earth element analysis.Mineralogical studies using X-ray diffraction analysis revealed prominent kaolinite, dickite and illite peaks; accessory minerals included quartz and microcline. Major element abundance showed thatthe shale samples had SiO2 (61.26%, Al2O3 (16.88% and Fe2O3 (3.75% constituting more than 79% of bulk chemical composition whilst claystone samples contained SiO2 (67.79%, Al2O3 (17.81% andFe2O3 (1.67%. Higher SiO2, Ba, Sr, V, and Nb concentrations were observed in claystone samples rather than shale whereas the shale samples were observed to be more Zr-, Ni- and Zn-enriched than theclaystone ones. The shale and claystone samples showed slightly light rare earth enrichment and slightly flat heavy rare earth depleted patterns having a negative Eu and Tm anomaly. High TiO2 and Rb/K2Ovalues also indicated that the shale and claystone samples were matured. Geochemical parameters such as U, U/Th, Ni/Co and Cu/Zn ratios indicated that these shales were deposited in oxic conditions; theAl2O3/TiO2 ratio suggested that intermediate igneous rocks were probable source rocks for the shales, while mafic rocks were suggested as being source rocks for the claystone. However, the La/Sc, Th/Sc, Th/Co ratios and shales and claystone plots revealed that they came within the range given for felsic rocks as provenance, thereby suggesting mixed provenace for the sediments. A passive-margin tectonic settingwas adduced for the sedimentary sequences.

  17. 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

  18. Sedimentary provenance in the southern sector of the São Francisco Basin, SE Brazil

    Directory of Open Access Journals (Sweden)

    Gustavo Macedo de Paula-Santos

    Full Text Available ABSTRACT: We present new Sm-Nd, U-Pb and Hf isotope geochronological data for the siliciclastic rocks in the southern sector of the São Francisco Basin. An abrupt change in the Sm-Nd data is observed from the Carrancas Formation’s oligomitic conglomerates (TDM ages between 2.7 and 3.3 Ga; εNd(550 Ma values between -25.09 and -17.98, its finer facies, and the finer facies of the the Moema Laminite (TDM ages from 1.4 to 2.1 Ga; εNd(550 Ma values between -9.46 and -5.59. No further significant changes in the Sm-Nd data occur farther upwards in the Bambuí Group (Sm-Nd TDM ages within the 1.3-2.0 Ga interval; εNd(550 Ma values from -9.53 to -4.09, showing a lack of reorganization in the source areas throughout the deposition of the basin. This is yet another argument to dismiss an unconformity within the Bambuí Group. The presence of the index fossil Cloudina sp. in the lower Sete Lagoas Formation makes the glaciation probably Late Ediacaran in age. U-Pb ages for detrital zircons of the Bambuí Group range from the Archean to the early Ediacaran, but the current data is insufficient to distinguish between the contribution from sources in the Brasília and Araçuaí belts.

  19. 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

  20. Water Quality and Soil Natural Salinity in the Southern Imera Basin (Sicily, Italy

    Directory of Open Access Journals (Sweden)

    Roberta Selvaggi

    2010-10-01

    Full Text Available The Southern Imera river crosses one of the most arid part of Sicily. The geochemical composition of the river water is due to the solubilization processes of gypsum rocks, which accounts for the particularly low quality of resources in the areas in which the presence of evaporitics deposits is highest. The geochemical composition and hydraulic parameters of river was monitored with the aim of reaching a better understanding of the relationships between litology and water quality. The Imera river is a potential local hydric resource, but seasonal variability of salinity does not allow farmers to use its water. A geochemical monitoring of the Imera river water has been carried out in selected localities integrating a GIS analysis of the river hydrography basin and of the distribution of the evaporitic formation. During 2003 and 2005 we performed four monitoring surveys of water chemicophysical parameters (temperature, pH and electrical conductivity and of the main ionic concentrations (Ca2+, Mg2+, K+, Na+, Cl-, SO4 2- . We also installed a multiparameter probe next to the hydrometrical station of Drasi, about 15 km from the river mouth. Such multiparameter probe was used to determine, continuously and simultaneously, temperature, electrical conductivity, pH, dissolved oxygen, redox potenzial, water level. The geochemical composition of the water allowed to confirm the results of Roda (1971 and Favara (2000, who pointed out that the main cause of degrade of the Southern Imera river are the salt-rich waters of some tributaries flowing over gypsum rocks and halite deposits. We have been able to identify which specific areas are the main contributors to the degradation of the Imera river.

  1. Preliminary assessment of the risk of volcanism at a proposed nuclear-waste repository in the southern Great Basin

    International Nuclear Information System (INIS)

    Crowe, B.M.; Carr, W.J.

    1980-01-01

    Volcanic hazard studies of the southern Great Basin are being conducted on behalf of the Nevada Nuclear Waste Storage Investigations program. Current work is chiefly concerned with characterizing the geology, chronology, and tectonic setting of Pliocene and Quaternary volcanism in the Nevada Test Site region, and assessing volcanic risk through consequence and probability studies, particularly with respect to a potential site in the southwestern Nevada Test Site. Young ( - 6 volcanic events per year. Based on this rate, the annual probability of disruption of a 10-km 2 repository located within a 25-km radius circle centered at Yucca Mountain, southwestern Nevada Test Site, is 10 - 8 . A larger area, 50-km radius, yields a disruption probability of 10 - 9 per year. Current tectonic zonation studies of the southern Great Basin will reduce the calculated probabilities of basaltic eruption for certain areas. 21 references, 3 figures

  2. Ruiniform relief in sandstones: the examples of Vila Velha, Carboniferous of the Paraná Basin, Southern Brazil

    OpenAIRE

    DE MELO, M.S.; COIMBRA, A.M.

    1996-01-01

    Vila Velha is a remarkable group of natural sculptures in Palaeozoicsandstones of the Paraná. Basin in Southern Brazil. The sculptures,which resemble the ruins of an old stone city, have resulted from thecombination of Cenozoic weathering and erosive processes with the existing attributes of the sedimentary rocks (texture, cementing oxides,sedimentary and brittle structures). A particular geomorphologic settingwith eroded inselbergs, and a differential iron and manganese cementationduring lat...

  3. Coalbed methane recovery from multilateral horizontal wells in Southern Qinshui Basin

    Directory of Open Access Journals (Sweden)

    Shenggui Liu

    2018-01-01

    Full Text Available Since 2006, more than 80 multilateral horizontal wells have been drilled in Panzhuang block, Southern Qinshui Basin. In this paper, 6 typical wells in a region are selected as an example. The thickness of coal, gas content, reservoir pressure, permeability, burial depth, and reservoir pressure conditions are analyzed. The practice shows that production by multilateral horizontal well declines from 43,111 m3/day per well in the 2nd year to 25,126 m3/day per well in the 4th year. The numerical simulation result shows that the lateral interference forms in Well QNP05 after two years of gas production, and the gas content is reduced to less than 8 m3/t within the controlled region after six years. The area of gas content was less than 8 m3/t after eight years of gas production is about 3.2 km2, which is about 76% of the controlled area of the six multilateral horizontal wells. The results indicate that multilateral horizontal wells contribute to high production rates at potentially profitable levels and can also serve as an effective tool for a high-rank CBM field drainage.

  4. Seasonality of macroalgal communities in a subtropical drainage basin in Paraná state, southern Brazil.

    Science.gov (United States)

    Branco, C C Z; Krupek, R A; Peres, C K

    2008-11-01

    Seasonal dynamics of macroalgal communities was analyzed monthly by samplings in three stream segments of the Pedras River Basin, mid-south region of Paraná State, southern Brazil, from April 2004 to March 2005. The seasonal fluctuations in macroalgal species richness and abundance were correlated with selected environmental variables. In general, the seasonal distribution patterns of these communities were distinct from those reported from other tropical and temperate regions, with higher macroalgal richness and abundance observed from late spring to late fall. Multiple linear regression analysis revealed that the stream variable most closely related with the temporal distribution pattern observed was temperature, which had a very similar seasonal pattern to the biological parameters. On the other hand, the floristic composition was quite diverse in the streams sampled. Among the 25 taxa identified, only two were common to the three streams whereas 15 were restricted to a single sampling site. These data indicate that, although temperature seems to be an effective relationship with global temporal pattern, particular characteristics of each stream can strongly influence the seasonal tendencies in local scale. The results of Detrended Correspondence Analysis (DCA) and Cluster Analysis corroborated this observation.

  5. Sedimentological Characteristics and Re-interpretation of the Paleoenvironment of Lokoja Sandstone, Southern Bida Basin, Nigeria

    International Nuclear Information System (INIS)

    Ojo, O. J.; Akande, S. O.

    2002-01-01

    Detail mapping of the Lokoja Formation consisting predominantly of sandstones exposed along Okene-Abuja highway near the confluence of Rivers Niger and Benue in the southern Bida Basin was undertaken in an attempt to reconstruct their depositional history. The analyses of the lithofacies characteristics, pebble morphogenesis and ichnofossil content of the Lokoja sandstones in the study area reveal their depositional environments which evolved from alluvial fans through braided stream into nearshore shallow marine conditions. The massive, immature, matrix to grain supported conglomerate subfacies can be interpreted as debris flow. The conglomeratic sandstone facies (massive, cross stratified and graded subfacies) reflect deposits of deep braided channels. The bioturbated and herringbone cross stratified conglomeratic sandstones indicate shallowing to marginal marine environments. The fine to medium grained sandstones, siltstones and claystones are interpreted as channel bars and floodplain deposits.Results of pebble morphogenesis analysis indicate predominance of fluvial processes. Minor high energy (probably beach) condition is indicated by some individual clasts from the conglomeratic sandstone facies with sphericity and OP index values less that 0.66 and -1.5 respectively.The study is significant because it represents the first sedimentological evidence of influence of shallow marine in the development of Lokoja sandstones during Campanian-Maastrichtian times

  6. Seasonality of macroalgal communities in a subtropical drainage basin in Paraná state, southern Brazil

    Directory of Open Access Journals (Sweden)

    CCZ. Branco

    Full Text Available Seasonal dynamics of macroalgal communities was analyzed monthly by samplings in three stream segments of the Pedras River Basin, mid-south region of Paraná State, southern Brazil, from April 2004 to March 2005. The seasonal fluctuations in macroalgal species richness and abundance were correlated with selected environmental variables. In general, the seasonal distribution patterns of these communities were distinct from those reported from other tropical and temperate regions, with higher macroalgal richness and abundance observed from late spring to late fall. Multiple linear regression analysis revealed that the stream variable most closely related with the temporal distribution pattern observed was temperature, which had a very similar seasonal pattern to the biological parameters. On the other hand, the floristic composition was quite diverse in the streams sampled. Among the 25 taxa identified, only two were common to the three streams whereas 15 were restricted to a single sampling site. These data indicate that, although temperature seems to be an effective relationship with global temporal pattern, particular characteristics of each stream can strongly influence the seasonal tendencies in local scale. The results of Detrended Correspondence Analysis (DCA and Cluster Analysis corroborated this observation.

  7. 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

  8. Emergency Assessment of Debris-Flow Hazards from Basins Burned by the 2007 Witch Fire, San Diego County, Southern California

    Science.gov (United States)

    Cannon, Susan H.; Gartner, Joseph E.; Michael, John A.; Bauer, Mark A.; Stitt, Susan C.; Knifong, Donna L.; McNamara, Bernard J.; Roque, Yvonne M.

    2007-01-01

    INTRODUCTION The objective of this report is to present a preliminary emergency assessment of the potential for debris-flow generation from basins burned by the Witch Fire in San Diego County, southern California in 2007. Debris flows are among the most hazardous geologic phenomena; debris flows that followed wildfires in southern California in 2003 killed 16 people and caused tens of millions of dollars of property damage. A short period of even moderate rainfall on a burned watershed can lead to debris flows. Rainfall that is normally absorbed into hillslope soils can run off almost instantly after vegetation has been removed by wildfire. This causes much greater and more rapid runoff than is normal from creeks and drainage areas. Highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud, boulders, and unburned vegetation. Within the burned area and downstream, the force of rushing water, soil, and rock can destroy culverts, bridges, roadways, and buildings, potentially causing injury or death. This emergency debris-flow hazard assessment is presented as relative ranking of the predicted median volume of debris flows that can issue from basin outlets in response to 2.25 inches (57.15 mm) of rainfall over a 3-hour period. Such a storm has a 10-year return period. The calculation of debris flow volume is based on a multiple-regression statistical model that describes the median volume of material that can be expected from a recently burned basin as a function of the area burned at high and moderate severity, the basin area with slopes greater than or equal to 30 percent, and triggering storm rainfall. Cannon and others (2007) describe the methods used to generate the hazard maps. Identification of potential debris-flow hazards from burned drainage basins is necessary to issue warnings for specific basins, to make effective mitigation decisions, and to help plan evacuation timing and routes.

  9. Emergency Assessment of Debris-Flow Hazards from Basins Burned by the 2007 Buckweed Fire, Los Angeles County, Southern California

    Science.gov (United States)

    Cannon, Susan H.; Gartner, Joseph E.; Michael, John A.; Bauer, Mark A.; Stitt, Susan C.; Knifong, Donna L.; McNamara, Bernard J.; Roque, Yvonne M.

    2007-01-01

    INTRODUCTION The objective of this report is to present a preliminary emergency assessment of the potential for debris-flow generation from basins burned by the Buckweed Fire in Los Angeles County, southern California in 2007. Debris flows are among the most hazardous geologic phenomena; debris flows that followed wildfires in southern California in 2003 killed 16 people and caused tens of millions of dollars of property damage. A short period of even moderate rainfall on a burned watershed can lead to debris flows. Rainfall that is normally absorbed into hillslope soils can run off almost instantly after vegetation has been removed by wildfire. This causes much greater and more rapid runoff than is normal from creeks and drainage areas. Highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud, boulders, and unburned vegetation. Within the burned area and downstream, the force of rushing water, soil, and rock can destroy culverts, bridges, roadways, and buildings, potentially causing injury or death. This emergency debris-flow hazard assessment is presented as relative ranking of the predicted median volume of debris flows that can issue from basin outlets in response to 2.25 inches (57.15 mm) of rainfall over a 3-hour period. Such a storm has a 10-year return period. The calculation of debris flow volume is based on a multiple-regression statistical model that describes the median volume of material that can be expected from a recently burned basin as a function of the area burned at high and moderate severity, the basin area with slopes greater than or equal to 30 percent, and triggering storm rainfall. Cannon and others (2007) describe the methods used to generate the hazard maps. Identification of potential debris-flow hazards from burned drainage basins is necessary to issue warnings for specific basins, to make effective mitigation decisions, and to help plan evacuation timing and routes.

  10. Emergency Assessment of Debris-Flow Hazards from Basins Burned by the 2007 Santiago Fire, Orange County, Southern California

    Science.gov (United States)

    Cannon, Susan H.; Gartner, Joseph E.; Michael, John A.; Bauer, Mark A.; Stitt, Susan C.; Knifong, Donna L.; McNamara, Bernard J.; Roque, Yvonne M.

    2007-01-01

    INTRODUCTION The objective of this report is to present a preliminary emergency assessment of the potential for debris-flow generation from basins burned by the Santiago Fire in Orange County, southern California in 2007. Debris flows are among the most hazardous geologic phenomena; debris flows that followed wildfires in southern California in 2003 killed 16 people and caused tens of millions of dollars of property damage. A short period of even moderate rainfall on a burned watershed can lead to debris flows. Rainfall that is normally absorbed into hillslope soils can run off almost instantly after vegetation has been removed by wildfire. This causes much greater and more rapid runoff than is normal from creeks and drainage areas. Highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud, boulders, and unburned vegetation. Within the burned area and downstream, the force of rushing water, soil, and rock can destroy culverts, bridges, roadways, and buildings, potentially causing injury or death. This emergency debris-flow hazard assessment is presented as relative ranking of the predicted median volume of debris flows that can issue from basin outlets in response to 1.75 inches (44.45 mm) of rainfall over a 3-hour period. Such a storm has a 10-year return period. The calculation of debris flow volume is based on a multiple-regression statistical model that describes the median volume of material that can be expected from a recently burned basin as a function of the area burned at high and moderate severity, the basin area with slopes greater than or equal to 30 percent, and triggering storm rainfall. Cannon and others (2007) describe the methods used to generate the hazard maps. Identification of potential debris-flow hazards from burned drainage basins is necessary to issue warnings for specific basins, to make effective mitigation decisions, and to help plan evacuation timing and routes.

  11. Emergency Assessment of Debris-Flow Hazards from Basins Burned by the 2007 Canyon Fire, Los Angeles County, Southern California

    Science.gov (United States)

    Cannon, Susan H.; Gartner, Joseph E.; Michael, John A.; Bauer, Mark A.; Stitt, Susan C.; Knifong, Donna L.; McNamara, Bernard J.; Roque, Yvonne M.

    2007-01-01

    INTRODUCTION The objective of this report is to present a preliminary emergency assessment of the potential for debris-flow generation from basins burned by the Canyon Fire in Los Angeles County, southern California in 2007. Debris flows are among the most hazardous geologic phenomena; debris flows that followed wildfires in southern California in 2003 killed 16 people and caused tens of millions of dollars of property damage. A short period of even moderate rainfall on a burned watershed can lead to debris flows. Rainfall that is normally absorbed into hillslope soils can run off almost instantly after vegetation has been removed by wildfire. This causes much greater and more rapid runoff than is normal from creeks and drainage areas. Highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud, boulders, and unburned vegetation. Within the burned area and downstream, the force of rushing water, soil, and rock can destroy culverts, bridges, roadways, and buildings, potentially causing injury or death. This emergency debris-flow hazard assessment is presented as relative ranking of the predicted median volume of debris flows that can issue from basin outlets in response to 2.25 inches (57.15 mm) of rainfall over a 3-hour period. Such a storm has a 10-year return period. The calculation of debris flow volume is based on a multiple-regression statistical model that describes the median volume of material that can be expected from a recently burned basin as a function of the area burned at high and moderate severity, the basin area with slopes greater than or equal to 30 percent, and triggering storm rainfall. Cannon and others (2007) describe the methods used to generate the hazard maps. Identification of potential debris-flow hazards from burned drainage basins is necessary to issue warnings for specific basins, to make effective mitigation decisions, and to help plan evacuation timing and routes.

  12. Emergency Assessment of Debris-Flow Hazards from Basins Burned by the 2007 Poomacha Fire, San Diego County, Southern California

    Science.gov (United States)

    Cannon, Susan H.; Gartner, Joseph E.; Michael, John A.; Bauer, Mark A.; Stitt, Susan C.; Knifong, Donna L.; McNamara, Bernard J.; Roque, Yvonne M.

    2007-01-01

    INTRODUCTION The objective of this report is to present a preliminary emergency assessment of the potential for debris-flow generation from basins burned by the Poomacha Fire in San Diego County, southern California in 2007. Debris flows are among the most hazardous geologic phenomena; debris flows that followed wildfires in southern California in 2003 killed 16 people and caused tens of millions of dollars of property damage. A short period of even moderate rainfall on a burned watershed can lead to debris flows. Rainfall that is normally absorbed into hillslope soils can run off almost instantly after vegetation has been removed by wildfire. This causes much greater and more rapid runoff than is normal from creeks and drainage areas. Highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud, boulders, and unburned vegetation. Within the burned area and downstream, the force of rushing water, soil, and rock can destroy culverts, bridges, roadways, and buildings, potentially causing injury or death. This emergency debris-flow hazard assessment is presented as relative ranking of the predicted median volume of debris flows that can issue from basin outlets in response to 2.25 inches (57.15 mm) of rainfall over a 3-hour period. Such a storm has a 10-year return period. The calculation of debris flow volume is based on a multiple-regression statistical model that describes the median volume of material that can be expected from a recently burned basin as a function of the area burned at high and moderate severity, the basin area with slopes greater than or equal to 30 percent, and triggering storm rainfall. Cannon and others (2007) describe the methods used to generate the hazard maps. Identification of potential debris-flow hazards from burned drainage basins is necessary to issue warnings for specific basins, to make effective mitigation decisions, and to help plan evacuation timing and routes.

  13. Emergency Assessment of Debris-Flow Hazards from Basins Burned by the 2007 Rice Fire, San Diego County, Southern California

    Science.gov (United States)

    Cannon, Susan H.; Gartner, Joseph E.; Michael, John A.; Bauer, Mark A.; Stitt, Susan C.; Knifong, Donna L.; McNamara, Bernard J.; Roque, Yvonne M.

    2007-01-01

    INTRODUCTION The objective of this report is to present a preliminary emergency assessment of the potential for debris-flow generation from basins burned by the Rice Fire in San Diego County, southern California in 2007. Debris flows are among the most hazardous geologic phenomena; debris flows that followed wildfires in southern California in 2003 killed 16 people and caused tens of millions of dollars of property damage. A short period of even moderate rainfall on a burned watershed can lead to debris flows. Rainfall that is normally absorbed into hillslope soils can run off almost instantly after vegetation has been removed by wildfire. This causes much greater and more rapid runoff than is normal from creeks and drainage areas. Highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud, boulders, and unburned vegetation. Within the burned area and downstream, the force of rushing water, soil, and rock can destroy culverts, bridges, roadways, and buildings, potentially causing injury or death. This emergency debris-flow hazard assessment is presented as relative ranking of the predicted median volume of debris flows that can issue from basin outlets in response to 1.75 inches (44.45 mm) of rainfall over a 3-hour period. Such a storm has a 10-year return period. The calculation of debris flow volume is based on a multiple-regression statistical model that describes the median volume of material that can be expected from a recently burned basin as a function of the area burned at high and moderate severity, the basin area with slopes greater than or equal to 30 percent, and triggering storm rainfall. Cannon and others (2007) describe the methods used to generate the hazard maps. Identification of potential debris-flow hazards from burned drainage basins is necessary to issue warnings for specific basins, to make effective mitigation decisions, and to help plan evacuation timing and routes.

  14. Emergency assessment of debris-flow hazards from basins burned by the 2007 Harris Fire, San Diego County, southern California

    Science.gov (United States)

    Cannon, Susan H.; Gartner, Joseph E.; Michael, John A.; Bauer, Mark A.; Stitt, Susan C.; Knifong, Donna L.; McNamara, Bernard J.; Roque, Yvonne M.

    2007-01-01

    IntroductionThe objective of this report is to present a preliminary emergency assessment of the potential for debris-flow generation from basins burned by the Harris Fire in San Diego County, southern California in 2007. Debris flows are among the most hazardous geologic phenomena; debris flows that followed wildfires in southern California in 2003 killed 16 people and caused tens of millions of dollars of property damage. A short period of even moderate rainfall on a burned watershed can lead to debris flows. Rainfall that is normally absorbed into hillslope soils can run off almost instantly after vegetation has been removed by wildfire. This causes much greater and more rapid runoff than is normal from creeks and drainage areas. Highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud, boulders, and unburned vegetation. Within the burned area and downstream, the force of rushing water, soil, and rock can destroy culverts, bridges, roadways, and buildings, potentially causing injury or death. This emergency debris-flow hazard assessment is presented as relative ranking of the predicted median volume of debris flows that can issue from basin outlets in response to 1.75 inches (44.45 mm) of rainfall over a 3-hour period. Such a storm has a 10-year return period. The calculation of debris flow volume is based on a multiple-regression statistical model that describes the median volume of material that can be expected from a recently burned basin as a function of the area burned at high and moderate severity, the basin area with slopes greater than or equal to 30 percent, and triggering storm rainfall. Cannon and others (2007) describe the methods used to generate the hazard maps. Identification of potential debris-flow hazards from burned drainage basins is necessary to issue warnings for specific basins, to make effective mitigation decisions, and to help plan evacuation timing and routes.

  15. Emergency Assessment of Debris-Flow Hazards from Basins Burned by the 2007 Ammo Fire, San Diego County, Southern California

    Science.gov (United States)

    Cannon, Susan H.; Gartner, Joseph E.; Michael, John A.; Bauer, Mark A.; Stitt, Susan C.; Knifong, Donna L.; McNamara, Bernard J.; Roque, Yvonne M.

    2007-01-01

    INTRODUCTION The objective of this report is to present a preliminary emergency assessment of the potential for debris-flow generation from basins burned by the Ammo Fire in San Diego County, southern California in 2007. Debris flows are among the most hazardous geologic phenomena; debris flows that followed wildfires in southern California in 2003 killed 16 people and caused tens of millions of dollars of property damage. A short period of even moderate rainfall on a burned watershed can lead to debris flows. Rainfall that is normally absorbed into hillslope soils can run off almost instantly after vegetation has been removed by wildfire. This causes much greater and more rapid runoff than is normal from creeks and drainage areas. Highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud, boulders, and unburned vegetation. Within the burned area and downstream, the force of rushing water, soil, and rock can destroy culverts, bridges, roadways, and buildings, potentially causing injury or death. This emergency debris-flow hazard assessment is presented as relative ranking of the predicted median volume of debris flows that can issue from basin outlets in response to 1.75 inches (44.45 mm) of rainfall over a 3-hour period. Such a storm has a 10-year return period. The calculation of debris flow volume is based on a multiple-regression statistical model that describes the median volume of material that can be expected from a recently burned basin as a function of the area burned at high and moderate severity, the basin area with slopes greater than or equal to 30 percent, and triggering storm rainfall. Cannon and others (2007) describe the methods used to generate the hazard maps. Identification of potential debris-flow hazards from burned drainage basins is necessary to issue warnings for specific basins, to make effective mitigation decisions, and to help plan evacuation timing and routes.

  16. Hydrologic assessment of three drainage basins in the Pinelands of southern New Jersey, 2004-06

    Science.gov (United States)

    Walker, Richard L.; Nicholson, Robert S.; Storck, Donald A.

    2011-01-01

    The New Jersey Pinelands is an ecologically diverse area in the southern New Jersey Coastal Plain, most of which overlies the Kirkwood-Cohansey aquifer system. The demand for groundwater from this aquifer system is increasing as local development increases. Because any increase in groundwater withdrawals has the potential to affect streamflows and wetland water levels, and ultimately threaten the ecological health and diversity of the Pinelands ecosystem, the U.S. Geological Survey, in cooperation with the New Jersey Pinelands Commission, began a multi-phase hydrologic investigation in 2004 to characterize the hydrologic system supporting the aquatic and wetland communities of the New Jersey Pinelands area (Pinelands). The current investigation of the hydrology of three representative drainage basins in the Pinelands (Albertson Brook, McDonalds Branch, and Morses Mill Stream basins) included a compilation of existing data; collection of water-level and streamflow data; mapping of the water-table altitude and depth to the water table; and analyses of water-level and streamflow variability, subsurface gradients and flow patterns, and water budgets. During 2004-06, a hydrologic database of existing and new data from wells and stream sites was compiled. Methods of data collection and analysis were defined, and data networks consisting of 471 wells and 106 surface-water sites were established. Hydrographs from 26 water-level-monitoring wells and four streamflow-gaging stations were analyzed to show the response of water levels and streamflow to precipitation and recharge with respect to the locations of these wells and streams within each basin. Water-level hydrographs show varying hydraulic gradients and flow potentials, and indicate that responses to recharge events vary with well depth and proximity to recharge and discharge areas. Results of the investigation provide a detailed characterization of hydrologic conditions, processes, and relations among the components

  17. Eocene Unification of Peruvian and Bolivian Altiplano Basin Depocenters

    Science.gov (United States)

    Saylor, J.; Sundell, K. E.; Perez, N.; Karsky, N.; Lapen, T. J.; Cárdenas, J.

    2017-12-01

    Paleogene evolution of the Altiplano basin has been characterized as a flexural foreland basin which developed in response to magmatic and thrust loading along its western margin. Research focused in southern Peru and Bolivia points to broadly synchronous foredeep deposition in a basin assumed to be have been contiguous from at least 14°-23°S. We investigated Paleogene strata exposed on the southwestern margin of Lake Titicaca near the Peru/Bolivia border in order to establish sediment dispersal systems, sediment sources, and the chronology of deposition. A data set of >1,000 paleocurrent measurements throughout the section consistently indicates a western sediment source. The results of detrital zircon mixture modeling are consistent with derivation from Cretaceous volcanic sources, and Cretaceous and Ordovician sedimentary strata exposed in the Western Cordillera. These results confirm previous models in which sedimentary sources for the Altiplano basin are dominated by the Western Cordillera throughout the Paleogene. The detrital zircon signatures from strata in this stratigraphic section where paleocurrent orientation is well constrained provide a benchmark for future research seeking to determine sediment sources for the Altiplano basin. However, refined chronologies based on detrital zircon U-Pb maximum depositional ages (MDAs) point to development of at least two Paleocene depocenters in Peru and Bolivia separated by a zone of nondeposition or erosion in southern Peru. The basal Muñani Formation in southern Peru yields MDAs of 36.9-40.2 Ma, which requires revision of the previously determined middle Paleocene onset of deposition. The Muñani Formation overlies the Vilquechico Group which has been biostratigraphically determined to range from Campanian-Maastrichtian (or possibly Paleocene, 60 Ma). The revised chronology for the Muñani Formation requires a disconformity of at least 20 Myr during which deposition continued in both the Peruvian and Bolivian

  18. The bi-decadal rainfall cycle, Southern Annular Mode and tropical cyclones over the Limpopo River Basin, southern Africa

    CSIR Research Space (South Africa)

    Malherbe, J

    2014-06-01

    Full Text Available contribution to rainfall by tropical cyclones and depressions. The findings suggest that a broadening of the Hadley circulation underpinned by an anomalous anticyclonic pattern to the east of southern Africa altered tropospheric steering flow, relative...

  19. 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 (<2.0 μm) from both fire

  20. Hydrogeologic investigations of the southern Española Basin, NM

    Science.gov (United States)

    Earney, T.; Christensen, D.; Horton, A.; Folsom, M.; Kelley, S.

    2017-12-01

    For the past 5 years, students participating in the Summer of Applied Geophysical Experience (SAGE) have been studying groundwater conditions in the southern Española Basin, in northern New Mexico, with a goal of developing a better understanding of both regional and local scale geothermal anomalies. A regional geothermal gradient map constructed over the study area indicates that there are two regions with anomalously high geothermal gradients, one associated with the Buckman municipal wellfield (BMWF) and the other in the vicinity of the Cerros del Rio volcanic field. Overproduction at the BMWF was responsible for a 100 meter drop in groundwater levels between 1989 and 2003, leading to a significant amount of land subsidence. Repeat measurements of thermal profiles for several monitoring wells at Buckman reveal incremental warming over a 5 year period from 2013 to 2017. Additionally, land elevation recovery was documented between 2007 and 2010 using InSAR (Interferometric Synthetic Aperture Radar). These observations are inferred to be a response to decreased production rates in nearby wells Buckman 1 and 8. This suggests that the groundwater flow system at Buckman is still in a state of recovery from the years of overproduction. The proximity of the well field to a small mapped fault near Buckman 8 potentially explains why geothermal gradients are anomalously high at the BMWF. Monitoring well SF-2b received special attention in an attempt to explain a localized thermal anomaly between 200 and 230 meters down hole. Explanations including geology (faults and stratigraphy) and interference from nearby production wells do not seem to account for the anomaly. The anomaly is therefore interpreted as the result of a damaged casing. Elevated geothermal anomalies at the Cerros del Rio volcanic field could be explained by structural and textural changes to groundwater flow units that occurred when aligned plug and dikes feeding volcanic vents intruded along faults. A

  1. Permian salt dissolution, alkaline lake basins, and nuclear-waste storage, Southern High Plains, Texas and New Mexico

    International Nuclear Information System (INIS)

    Reeves, C.C. Jr.; Temple, J.M.

    1986-01-01

    Areas of Permian salt dissolution associated with 15 large alkaline lake basins on and adjacent to the Southern High Plains of west Texas and eastern New Mexico suggest formation of the basins by collapse of strata over the dissolution cavities. However, data from 6 other alkaline basins reveal no evidence of underlying salt dissolution. Thus, whether the basins were initiated by subsidence over the salt dissolution areas or whether the salt dissolution was caused by infiltration of overlying lake water is conjectural. However, the fact that the lacustrine fill in Mound Lake greatly exceeds the amount of salt dissolution and subsidence of overlying beds indicates that at least Mound Lake basin was antecedent to the salt dissolution. The association of topography, structure, and dissolution in areas well removed from zones of shallow burial emphasizes the susceptibility of Permian salt-bed dissolution throughout the west Texas-eastern New Mexico area. Such evidence, combined with previous studies documenting salt-bed dissolution in areas surrounding a proposed high-level nuclear-waste repository site in Deaf Smith County, Texas, leads to serious questions about the rationale of using salt beds for nuclear-waste storage

  2. Timing of maximum glacial extent and deglaciation from HualcaHualca volcano (southern Peru), obtained with cosmogenic 36Cl.

    Science.gov (United States)

    Alcalá, Jesus; Palacios, David; Vazquez, Lorenzo; Juan Zamorano, Jose

    2015-04-01

    Andean glacial deposits are key records of climate fluctuations in the southern hemisphere. During the last decades, in situ cosmogenic nuclides have provided fresh and significant dates to determine past glacier behavior in this region. But still there are many important discrepancies such as the impact of Last Glacial Maximum or the influence of Late Glacial climatic events on glacial mass balances. Furthermore, glacial chronologies from many sites are still missing, such as HualcaHualca (15° 43' S; 71° 52' W; 6,025 masl), a high volcano of the Peruvian Andes located 70 km northwest of Arequipa. The goal of this study is to establish the age of the Maximum Glacier Extent (MGE) and deglaciation at HualcaHualca volcano. To achieve this objetive, we focused in four valleys (Huayuray, Pujro Huayjo, Mollebaya and Mucurca) characterized by a well-preserved sequence of moraines and roches moutonnées. The method is based on geomorphological analysis supported by cosmogenic 36Cl surface exposure dating. 36Cl ages have been estimated with the CHLOE calculator and were compared with other central Andean glacial chronologies as well as paleoclimatological proxies. In Huayuray valley, exposure ages indicates that MGE occurred ~ 18 - 16 ka. Later, the ice mass gradually retreated but this process was interrupted by at least two readvances; the last one has been dated at ~ 12 ka. In the other hand, 36Cl result reflects a MGE age of ~ 13 ka in Mollebaya valley. Also, two samples obtained in Pujro-Huayjo and Mucurca valleys associated with MGE have an exposure age of 10-9 ka, but likely are moraine boulders affected by exhumation or erosion processes. Deglaciation in HualcaHualca volcano began abruptly ~ 11.5 ka ago according to a 36Cl age from a polished and striated bedrock in Pujro Huayjo valley, presumably as a result of reduced precipitation as well as a global increase of temperatures. The glacier evolution at HualcaHualca volcano presents a high correlation with

  3. Mercury Levels in Human Hair and Farmed Fish near Artisanal and Small-Scale Gold Mining Communities in the Madre de Dios River Basin, Peru

    Directory of Open Access Journals (Sweden)

    Aubrey L. Langeland

    2017-03-01

    Full Text Available Artisanal and small-scale gold mining (ASGM has been an important source of income for communities in the Madre de Dios River Basin in Peru for hundreds of years. However, in recent decades, the scale of ASGM activities in the region has increased dramatically, and exposures to a variety of occupational and environmental hazards related to ASGM, including mercury, are becoming more widespread. The aims of our study were to: (1 examine patterns in the total hair mercury level of human participants in several communities in the region and compare these results to the 2.2 µg/g total hair mercury level equivalent to the World Health Organization (WHO Expert Committee of Food Additives (JECFA’s Provisional Tolerable Weekly Intake (PTWI; and (2, to measure the mercury levels of paco (Piaractus brachypomus fish raised in local aquaculture ponds, in order to compare these levels to the EPA Fish Tissue Residue Criterion of 0.3 µg Hg/g fish (wet weight. We collected hair samples from 80 participants in four communities (one control and three where ASGM activities occurred in the region, and collected 111 samples from fish raised in 24 local aquaculture farms. We then analyzed the samples for total mercury. Total mercury levels in hair were statistically significantly higher in the mining communities than in the control community, and increased with increasing geodesic distance from the Madre de Dios headwaters, did not differ by sex, and frequently exceeded the reference level. Regression analyses indicated that higher hair mercury levels were associated with residence in ASGM communities. The analysis of paco fish samples found no samples that exceeded the EPA tissue residue criterion. Collectively, these results align with other recent studies showing that ASGM activities are associated with elevated human mercury exposure. The fish farmed through the relatively new process of aquaculture in ASGM areas appeared to have little potential to contribute

  4. Mercury Levels in Human Hair and Farmed Fish near Artisanal and Small-Scale Gold Mining Communities in the Madre de Dios River Basin, Peru.

    Science.gov (United States)

    Langeland, Aubrey L; Hardin, Rebecca D; Neitzel, Richard L

    2017-03-14

    Artisanal and small-scale gold mining (ASGM) has been an important source of income for communities in the Madre de Dios River Basin in Peru for hundreds of years. However, in recent decades, the scale of ASGM activities in the region has increased dramatically, and exposures to a variety of occupational and environmental hazards related to ASGM, including mercury, are becoming more widespread. The aims of our study were to: (1) examine patterns in the total hair mercury level of human participants in several communities in the region and compare these results to the 2.2 µg/g total hair mercury level equivalent to the World Health Organization (WHO) Expert Committee of Food Additives (JECFA)'s Provisional Tolerable Weekly Intake (PTWI); and (2), to measure the mercury levels of paco ( Piaractus brachypomus ) fish raised in local aquaculture ponds, in order to compare these levels to the EPA Fish Tissue Residue Criterion of 0.3 µg Hg/g fish (wet weight). We collected hair samples from 80 participants in four communities (one control and three where ASGM activities occurred) in the region, and collected 111 samples from fish raised in 24 local aquaculture farms. We then analyzed the samples for total mercury. Total mercury levels in hair were statistically significantly higher in the mining communities than in the control community, and increased with increasing geodesic distance from the Madre de Dios headwaters, did not differ by sex, and frequently exceeded the reference level. Regression analyses indicated that higher hair mercury levels were associated with residence in ASGM communities. The analysis of paco fish samples found no samples that exceeded the EPA tissue residue criterion. Collectively, these results align with other recent studies showing that ASGM activities are associated with elevated human mercury exposure. The fish farmed through the relatively new process of aquaculture in ASGM areas appeared to have little potential to contribute to human

  5. 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.

  6. Basin geodynamics and sequence stratigraphy of Upper Triassic to Lower Jurassic deposits of Southern Tunisia

    Science.gov (United States)

    Carpentier, Cédric; Hadouth, Suhail; Bouaziz, Samir; Lathuilière, Bernard; Rubino, Jean-Loup

    2016-05-01

    Aims of this paper are to propose a geodynamic and sequential framework for the late Triassic and early Jurassic of and south Tunisia and to evidence the impact of local tectonics on the stratigraphic architecture. Facies of the Upper Triassic to Lower Jurassic of Southern Tunisia have been interpreted in terms of depositional environments. A sequential framework and correlation schemes are proposed for outcrops and subsurface transects. Nineteen middle frequency sequences inserted in three and a half low frequency transgression/regression cycles were evidenced. Despite some datation uncertainties and the unknown durations of Lower Jurassic cycles, middle frequency sequences appear to be controlled by eustasy. In contrast the tectonics acted as an important control on low frequency cycles. The Carnian flooding was certainly favored by the last stages of a rifting episode which started during the Permian. The regression accompanied by the formation of stacked angular unconformities and the deposition of lowstand deposits during the late Carnian and Norian occured during the uplift and tilting of the northern basin margins. The transpressional activity of the Jeffara fault system generated the uplift of the Tebaga of Medenine high from the late Carnian and led to the Rhaetian regional angular Sidi Stout Unconformity. Facies analysis and well-log correlations permitted to evidence that Rhaetian to Lower Jurassic Messaoudi dolomites correspond to brecciated dolomites present on the Sidi Stout unconformity in the North Dahar area. The Early-cimmerian compressional event is a possible origin for the global uplift of the northern African margin and Western Europe during the late Carnian and the Norian. During the Rhaetian and the early Jurassic a new episode of normal faulting occured during the third low frequency flooding. This tectonosedimentary evolution ranges within the general geodynamic framework of the north Gondwana margin controlled by the opening of both

  7. 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

  8. STRATIGRAPHY OF THE CARNIAN - NORIAN CALCARI CON SELCE FORMATION IN THE LAGONEGRO BASIN, SOUTHERN APENNINES

    Directory of Open Access Journals (Sweden)

    MANUEL RIGO

    2012-03-01

    Full Text Available The Upper Triassic Calcari con Selce Formation, cropping out in the southern Apennines (S Italy, consists of 400 m of micritic limestones, often nodular, with chert beds and nodules, organized in dm to m beds intercalated with mm (rarely centimetric marly horizons. Three intervals characterized by higher siliciclastic content have been recognized within this formation, and stratigraphically ordered after an accurate conodont biostratigraphical investigation: 1 the green clay-radiolaritic horizon, previously named in literature with the informal expression of “livello argilloso ad Halobia superba”, Tuvalian (upper Carnian; 2 an interval of some tens of meters of limestones and brown shales with abundant chert beds, here informally termed the "brown member", Tuvalian/Lacian (upper Carnian/lower Norian; 3 the ca. 3 m thick red shale horizon, Sevatian (upper Norian in age. All these intervals are characterized by micritic limestones or marly limestones with bivalves, radiolarians and conodonts alternating with shales (green, brown or red having thicknesses of 50 cm or more. These intervals are also associated to an increase of calciturbidites, consisting of echinoderm fragments, isolated thin-shelled bivalves and reworked, partially lithified intraclasts of the Calcari con Selce Fm. The Carnian green clay-radiolaritic horizon and the Sevatian red siliciclastic interval are useful lithostratigraphic markers recognizable throughout the Lagonegro Basin and have been used as guide horizons to evaluate the lateral continuity of contiguous limestone beds. The green clay-radiolaritic horizon has been logged in 4 sections (Pignola 2, Mt. Armizzone, Pezza la Quagliara, San Michele. The sections are presently at approximately 50 km distance - but Tertiary thrusts occur between the sections, suggesting a larger separation at the time of the deposition of the Formation. Above the green clay-radiolaritic horizon, single carbonate beds or banks with the same

  9. Characterization of water quality for streams in the southern Yampa River basin, northwestern Colorado. Water Resources Investigation

    International Nuclear Information System (INIS)

    Parker, R.S.

    1991-01-01

    Historically, the Yampa River basin in northwestern Colorado has been an area of coal-mining development. Coal mining generally has been developed in the southern part of the basin and at lower elevations. The purpose of the report is to characterize the stream water quality by summarizing selected major dissolved constituents for the streams that drain the southern part of the Yampa River basin. Characterization is done initially by providing a statistical summary of the constituents for individual water-quality sites in the study area. These statistical summaries can be used to help assess water-quality within specified stream reaches. Water-quality data are available for sites on most perennial streams in the study area, and these data provide the best information about the immediate stream reach. Water-quality data from all sites are combined into regions, and linear-regression equations between dissolved constituents and specific conductance are calculated. Such equations provide an estimate of the water-quality relations within these regions. The equations also indicate an increase in error as individual sites are combined

  10. 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.

  11. Tectonics, climate and mountain building in the forearc of southern Peru recorded in the 10Be chronology of low-relief surface abandonment

    Science.gov (United States)

    Hall, S. R.; Farber, D.; Audin, L.; Finkel, R. C.

    2009-12-01

    Regional low-relief surfaces have long been recognized as key features to understanding the response of landscapes to surface uplift. The canonical models of low-relief surface formation involve an extended period of tectonic quiescence during which, the fluvial systems bevel the landscape to a uniform elevation. This quiescent period is punctuated by a period(s) of surface uplift, which causes fluvial incision thereby abandoning the low-relief landscape. Over time, as rivers continue to incise in response to changes in sediment supply, river discharge, and base level fall, pieces of the relict low-relief landscape are left as abandoned remnants stranded above active channels. By determining the age of abandoned surfaces, previous workers have identified the onset of a change in the tectonic or climatic setting. One key assumption of this model is that the low-relief surfaces are truly abandoned with no current processes further acting on the surface. To improve our understanding of the underlying assumptions and problems of low-relief surface formation, we have used detailed mapping and absolute dating with cosmogenic 10Be to investigate surfaces in the hyperarid forearc region of southern Peru between ~14° and 18°S. Within this region, marine terraces and strath terraces reflect Plio-Pleistocene surface uplift, and together with the hyperarid climate, ongoing surface uplift provides a perfect natural laboratory to examine the processes affecting low-relief surface abandonment and preservation. With our new chronology we address: 1) the space and time correlations of surfaces, 2) incision rates of streams in response to base-level fall, and 3) surface erosion rates. Multiple surfaces have yielded 10Be surface abandonment ages that span >2 Ma - ~35 ka. While most of the surfaces we have dated are considerably less than 1 Ma, we have located two surfaces which are likely older than 2 Ma and constrain regional erosion rates to be chronology of Pleistocene surface

  12. Sedimentary record of subsidence pulse at the Triassic/Jurassic boundary interval in the Slovenian Basin (eastern Southern Alps

    Directory of Open Access Journals (Sweden)

    Rožič Boštjan

    2017-08-01

    Full Text Available In the Alpine Realm the Early Jurassic is characterized by the disintegration and partial drowning of vast platform areas. In the eastern part of the Southern Alps (present-day NW Slovenia, the Julian Carbonate Platform and the adjacent, E-W extending Slovenian Basin underwent partial disintegration, drowning and deepening from the Pliensbachian on, whereas only nominal environmental changes developed on the large Dinaric (Friuli, Adriatic Carbonate Platform to the south (structurally part of the Dinarides. These events, however, were preceded by an earlier - and as yet undocumented extensional event - that took place near the Triassic/Jurassic boundary. This paper provides evidence of an accelerated subsidence from four selected areas within the Slovenian Basin, which show a trend of eastwardly-decreasing deformation. In the westernmost (Mrzli vrh section - the Upper Triassic platform-margin - massive dolomite is overlain by the earliest Jurassic toe-of-slope carbonate resediments and further, by basin-plain micritic limestone. Further east (Perbla and Liščak sections the Triassic-Jurassic transition interval is marked by an increase in resedimented carbonates. We relate this to the increasing inclination and segmentation of the slope and adjacent basin floor. The easternmost (Mt. Porezen area shows a rather monotonous, latest Triassic-Early Jurassic basinal sedimentation. However, changes in the thickness of the Hettangian-Pliensbachian Krikov Formation point to a tilting of tectonic blocks within the basin area. Lateral facies changes at the base of the formation indicate that the tilting occurred at and/or shortly after the Triassic/Jurassic boundary

  13. Sedimentary record of subsidence pulse at the Triassic/Jurassic boundary interval in the Slovenian Basin (eastern Southern Alps)

    Science.gov (United States)

    Rožič, Boštjan; Jurkovšek, Tea Kolar; Rožič, Petra Žvab; Gale, Luka

    2017-08-01

    In the Alpine Realm the Early Jurassic is characterized by the disintegration and partial drowning of vast platform areas. In the eastern part of the Southern Alps (present-day NW Slovenia), the Julian Carbonate Platform and the adjacent, E-W extending Slovenian Basin underwent partial disintegration, drowning and deepening from the Pliensbachian on, whereas only nominal environmental changes developed on the large Dinaric (Friuli, Adriatic) Carbonate Platform to the south (structurally part of the Dinarides). These events, however, were preceded by an earlier - and as yet undocumented extensional event - that took place near the Triassic/Jurassic boundary. This paper provides evidence of an accelerated subsidence from four selected areas within the Slovenian Basin, which show a trend of eastwardly-decreasing deformation. In the westernmost (Mrzli vrh) section - the Upper Triassic platform-margin - massive dolomite is overlain by the earliest Jurassic toe-of-slope carbonate resediments and further, by basin-plain micritic limestone. Further east (Perbla and Liščak sections) the Triassic-Jurassic transition interval is marked by an increase in resedimented carbonates. We relate this to the increasing inclination and segmentation of the slope and adjacent basin floor. The easternmost (Mt. Porezen) area shows a rather monotonous, latest Triassic-Early Jurassic basinal sedimentation. However, changes in the thickness of the Hettangian-Pliensbachian Krikov Formation point to a tilting of tectonic blocks within the basin area. Lateral facies changes at the base of the formation indicate that the tilting occurred at and/or shortly after the Triassic/Jurassic boundary

  14. Hydrologic analysis of the challenges facing water resources and sustainable development of Wadi Feiran basin, southern Sinai, Egypt

    Science.gov (United States)

    Ahmed, Ayman A.; Diab, Maghawri S.

    2018-04-01

    Wadi Feiran basin is one of the most promising areas in southern Sinai (Egypt) for establishing new communities and for growth in agriculture, tourism, and industry. The present challenges against development include water runoff hazards (flash flooding), the increasing water demand, and water scarcity and contamination. These challenges could be mitigated by efficient use of runoff and rainwater through appropriate management, thereby promoting sustainable development. Strategies include the mitigation of runoff hazards and promoting the natural and artificial recharge of aquifers. This study uses a watershed modeling system, geographic information system, and classification scheme to predict the effects of various mitigation options on the basin's water resources. Rainwater-harvesting techniques could save more than 77% of the basin's runoff (by volume), which could be used for storage and aquifer recharge. A guide map is provided that shows possible locations for the proposed mitigation options in the study basin. Appropriate measures should be undertaken urgently: mitigation of groundwater contamination (including effective sewage effluent management); regular monitoring of the municipal, industrial and agricultural processes that release contaminants; rationalization and regulation of the application of agro-chemicals to farmland; and regular monitoring of contaminants in groundwater. Stringent regulations should be implemented to prevent wastewater disposal to the aquifers in the study area.

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

    International Nuclear Information System (INIS)

    Harmsen, S.C.

    1994-01-01

    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

  16. 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.

  17. Lower Badenian coarse-grained Gilbert deltas in the southern margin of the Western Carpathian Foredeep basin

    Science.gov (United States)

    Nehyba, Slavomír

    2018-02-01

    Two coarse-grained Gilbert-type deltas in the Lower Badenian deposits along the southern margin of the Western Carpathian Foredeep (peripheral foreland basin) were newly interpreted. Facies characterizing a range of depositional processes are assigned to four facies associations — topset, foreset, bottomset and offshore marine pelagic deposits. The evidence of Gilbert deltas within open marine deposits reflects the formation of a basin with relatively steep margins connected with a relative sea level fall, erosion and incision. Formation, progradation and aggradation of the thick coarse-grained Gilbert delta piles generally indicate a dramatic increase of sediment supply from the hinterland, followed by both relatively continuous sediment delivery and an increase in accommodation space. Deltaic deposition is terminated by relatively rapid and extended drowning and is explained as a transgressive event. The lower Gilbert delta was significantly larger, more areally extended and reveals a more complicated stratigraphic architecture than the upper one. Its basal surface represents a sequence boundary and occurs around the Karpatian/Badenian stratigraphic limit. Two coeval deltaic branches were recognized in the lower delta with partly different stratigraphic arrangements. This different stratigraphic architecture is mostly explained by variations in the sediment delivery and /or predisposed paleotopography and paleobathymetry of the basin floor. The upper delta was recognized only in a restricted area. Its basal surface represents a sequence boundary probably reflecting a higher order cycle of a relative sea level rise and fall within the Lower Badenian. Evidence of two laterally and stratigraphically separated coarse-grained Gilbert deltas indicates two regional/basin wide transgressive/regressive cycles, but not necessarily of the same order. Provenance analysis reveals similar sources of both deltas. Several partial source areas were identified (Mesozoic

  18. Breaching of strike-slip faults and flooding of pull-apart basins to form the southern Gulf of California seaway from 8 to 6 Ma

    Science.gov (United States)

    Umhoefer, P. J.; Skinner, L. A.; Oskin, M. E.; Dorsey, R. J.; Bennett, S. E. K.; Darin, M. H.

    2017-12-01

    Studies from multiple disciplines delineate the development of the oblique-divergent Pacific - North America plate boundary in the southern Gulf of California. Integration of onshore data from the Loreto - Santa Rosalia margin with offshore data from the Pescadero, Farallon, and Guaymas basins provides a detailed geologic history. Our GIS-based paleotectonic maps of the plate boundary from 9 to 6 Ma show that evolution of pull-apart basins led to the episodic northwestward encroachment of the Gulf of California seaway. Because adjacent pull-apart basins commonly have highlands between them, juxtaposition of adjacent basin lows during translation and pull apart lengthening played a critical role in seaway flooding. Microfossils and volcanic units date the earliest marine deposits at 9(?) - 8 Ma at the mouth of the Gulf. By ca. 8 Ma, the seaway had flooded north to the Pescadero basin, while the Loreto fault and the related fault-termination basin was proposed to have formed along strike at the plate margin. East of Loreto basin, a short topographic barrier between the Pescadero and Farallon pull-apart basins suggests that the Farallon basin was either a terrestrial basin, or if breaching occurred, it may contain 8 Ma salt or marine deposits. This early southern seaway formed along a series of pull-apart basins within a narrow belt of transtension structurally similar to the modern Walker Lane in NV and CA. At ca. 7 Ma, a series of marine incursions breached a 75-100 km long transtensional fault barrier between the Farallon and Guaymas basins offshore Bahía Concepción. Repeated breaching events and the isolation of the Guaymas basin in a subtropical setting formed a 2 km-thick salt deposit imaged in offshore seismic data, and thin evaporite deposits in the onshore Santa Rosalia basin. Lengthening of the Guaymas, Yaqui, and Tiburon basins caused breaches of the intervening Guaymas and Tiburón transforms by 6.5-6.3 Ma, forming a permanent 1500 km-long marine seaway

  19. 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. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  20. Forage Options for Dairy Farms with Reduced Water Availability in the Southern Murray Darling Basin of Australia

    Directory of Open Access Journals (Sweden)

    Mary-Jane Rogers

    2017-12-01

    Full Text Available The dairy industry in the southern Murray Darling Basin region of Australia is a major consumer of irrigation water because rainfall is low relative to evapotranspiration and the industrys relies heavily on irrigated temperate pastures and fodder crops. Water reforms, and potential climate change scenarios for this region suggest that there will be an overall decline in rainfall and water available for irrigation in the future. For the irrigated dairy industry to remain economically viable, there is a need for dairy farmers to improve the water productivity (WP of their forage systems and to be able to respond to year-to-year, and within year, variation in water availability. Researchers and dairy farmers are evaluating strategies to increase WP. These include: (i selecting better-adapted species for current and predicted climatic conditions; (ii using species that can survive and still be productive under reduced irrigation and then recover when full irrigation is restored; (iii modifying irrigation strategies to reduce water use whilst maintaining WP; and (iv grazing management strategies that facilitate the survival during, and recovery after, periods of moisture stress. This review will examine these strategies and discusses their potential to optimise forage production from irrigation water inputs so that the dairy industry in the southern Murray Darling Basin remains viable in the future.

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

    International Nuclear Information System (INIS)

    Hetland, Donald L.; Michie, Uisdean McL.

    1981-01-01

    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

  2. Biological characteristics of Central Indian Basin waters during the southern summer

    Digital Repository Service at National Institute of Oceanography (India)

    Matondkar, S.G.P.; Nair, K.K.C.; Ansari, Z.A.

    Phytoplankton biomass, taxonomy, primary productivity, and photosynthetically available radiation (PAR) were studied as part of baseline data collection for prospective nodule mining in the Central Indian Basin during the ORV Sagar Kanya cruise SK...

  3. Assessment of radiation background level of Shandong basin in east line of northward rerouting of southern river

    International Nuclear Information System (INIS)

    Deng Daping; Xu Jiaang; Zhu Jianguo; Chen Yingmin; Lu Feng; Song Gang; Cao Jingli

    2007-01-01

    Objective: To assess the radiation background levels of Shandong basin in east line of northward rerouting of southern river. Methods: The activity concentrations of gross-alpha, gross-beta, 137 Cs, 238 U, 232 Th, 40 K, 226 Ra and 90 Sr in the samples were measured by national standard methods respectively. The values of the dose conversion factor given by UNSCEAR 2000 were adopted for dose estimation. Results: The average activity concentrations of gross-alpha, gross-beta, 137 Cs, 238 U, 232 Th, 40 K, 226 Ra and 90 Sr in the samples were pooled in order to analyze dose estimation. The committed effective doses of the 226 Ra, 238 U, 90 Sr, 232 Th and 137 Cs from lake water for residents are 1.46, 4.95 x 10 -1 , 1.24 x 10 -1 , 2.58 x 10 -2 and 7.93 x 10 -3 μSv per year respectively. The committed effective doses of the 226 Ra, 238 U and 90 Sr from cyprinoid fish are 5.49 x 10 -2 , 3.69 x 10 -2 and 1.77 x 10 -2 μSv per year respectively. Conclusions: The results show that the average activity concentrations of gross-alpha, gross-beta, 137 Cs, 238 U, 232 Th, 40 K, 226 Ra and 90 Sr in the samples from Shandong basin of northward rerouting of southern river are within the background levels. And in the main lake basin, the estimated exposures of public caused by the radionuclide in water and cyprinoid fish are so low that they can be ignored unless there ate some radioactive contamination in the future. (authors)

  4. Sedimentary and tectonic evolution of the southern Qiangtang basin: Implications for the Lhasa-Qiangtang collision timing

    Science.gov (United States)

    Ma, Anlin; Hu, Xiumian; Garzanti, Eduardo; Han, Zhong; Lai, Wen

    2017-07-01

    The Mesozoic stratigraphic record of the southern Qiangtang basin in central Tibet records the evolution and closure of the Bangong-Nujiang ocean to the south. The Jurassic succession includes Toarcian-Aalenian shallow-marine limestones (Quse Formation), Aalenian-Bajocian feldspatho-litho-quartzose to feldspatho-quartzo-lithic sandstones (shallow-marine Sewa Formation and deep-sea Gaaco Formation), and Bathonian outer platform to shoal limestones (Buqu Formation). This succession is truncated by an angular unconformity, overlain by upper Bathonian to lower Callovian fan-delta conglomerates and litho-quartzose to quartzo-lithic sandstones (Biluoco Formation) and Callovian shoal to outer platform limestones (Suowa Formation). Sandstone petrography coupled with detrital-zircon U-Pb and Hf isotope analysis indicate that the Sewa and Gaaco formations contain intermediate to felsic volcanic detritus and youngest detrital zircons (183-170 Ma) with ɛHf(t) ranging widely from +13 to -25, pointing to continental-arc provenance from igneous rocks with mixed mantle and continental-crust contributions. An arc-trench system thus developed toward the end of the Early Jurassic, with the southern Qiangtang basin representing the fore-arc basin. Above the angular unconformity, the Biluoco Formation documents a change to dominant sedimentary detritus including old detrital zircons (mainly >500 Ma ages in the lower part of the unit) with age spectra similar to those from Paleozoic strata in the central Qiangtang area. A major tectonic event with intense folding and thrusting thus took place in late Bathonian time (166 ± 1 Ma), when the Qiangtang block collided with another microcontinental block possibly the Lhasa block.

  5. Hydrological Responses to Changes in the Rainfall Regime are Less Pronounced in Forested Basins: an Analysis of Southern Brazil, 1975-2010

    Science.gov (United States)

    Chagas, V. B. P.; Chaffe, P. L. B.

    2017-12-01

    It is unknown to what extent the hydrological responses to changes in the rainfall regime vary across forested and non-forested landscapes. Southern Brazil is approximately 570000 km² and was naturally covered mostly by tropical and subtropical forests. In the last century, a large proportion of forests were replaced by agricultural activities. The rainfall regime has also changed substantially in the last decades. The annual rainfall, number and magnitude of extreme events, and number of non-rainy days have increased in most of the area. In this study, we investigated the changes in the regime of 142 streamflow gauges and 674 rainfall gauges in Southern Brazil, from 1975 to 2010. The changes in the regime were analyzed for forested basins (i.e., with more than 50% forest coverage) and non-forested basins (i.e., with less than 20% forest coverage). The area of the river basins ranged from 100 to 60000 km². We analyzed a total of six signatures that represent the regime, including annual averages, seasonality, floods, and droughts. The statistical trends of the signatures were calculated using the Mann-Kendall test and the Sen's slope. The results showed that the majority of basins with opposing signal trends for mean annual streamflow and rainfall are non-forested basins (i.e., basins with higher anthropogenic impacts). Forested basins had a lower correlation between trends in the streamflow and rainfall trends for the seasonality and the average duration of drought events. There was a lower variability in the annual maximum 1-day streamflow trends in the forested basins. Additionally, despite a decrease in the 31-day rainfall minima and an increase in the seasonality, in forested basins the 7-day streamflow minima increases were substantially larger than in non-forested basins. In summary, the forested basins were less responsive to the changes in the precipitation 1-day maxima, seasonality, number of dry days, and 31-day minima.

  6. 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

  7. Solar energy in Peru

    Energy Technology Data Exchange (ETDEWEB)

    Pierson, H.

    1981-12-01

    The past, present, and future of Peru is discussed in terms of solar energy development and the social, economic, climatic, and technical factors involved. It is pointed out that there are 3 geographical divisions in Peru including: (1) the foggy coastal strip where rain is infrequent, insolation is low and population is high; (2) the mountainous Andes region with high insolation and many populated high mountain valleys; and (3) the rainy, Amazon basin covered with jungle, and sparcely populated with high but inconsistent insolation. Since there is little competition with other forms of energy, solar energy shows promise. Passive solar heating of buildings, particularly in the Andes region, is described, as well as the use of solar water heaters. Prototypes are described and illustrated. Industrial use of solar heated water in the wool industry as well as solar food drying and solar desalination are discussed. High temperature applications (electrical generators and refrigeration) as well as photovoltaic systems are discussed briefly. It is concluded that social and political factors are holding back the development of solar energy but a start (in the form of prototypes and demonstration programs) is being made. (MJJ)

  8. Timing of the Cenozoic basins of Southern Mexico and its relationship with the Pacific truncation process: Subduction erosion or detachment of the Chortís block

    Science.gov (United States)

    Silva-Romo, Gilberto; Mendoza-Rosales, Claudia Cristina; Campos-Madrigal, Emiliano; Hernández-Marmolejo, Yoalli Bianii; de la Rosa-Mora, Orestes Antonio; de la Torre-González, Alam Israel; Bonifacio-Serralde, Carlos; López-García, Nallely; Nápoles-Valenzuela, Juan Ivan

    2018-04-01

    In the central sector of the Sierra Madre del Sur in Southern Mexico, between approximately 36 and 16 Ma ago and in the west to east direction, a diachronic process of the formation of ∼north-south trending fault-bounded basins occurred. No tectono-sedimentary event in the period between 25 and 20 Ma is recognized in the study region. A period during which subduction erosion truncated the continental crust of southern Mexico has been proposed. The chronology, geometry and style of the formation of the Eocene Miocene fault-bounded basins are more congruent with crustal truncation by the detachment of the Chortís block, thus bringing into question the crustal truncation hypothesis of the Southern Mexico margin. Between Taxco and Tehuacán, using seven new Laser Ablation- Inductively-coupled plasma mass spectrometry (LA-ICP-MS) U-Pb ages in magmatic zircons, we refine the stratigraphy of the Tepenene, Tehuitzingo, Atzumba and Tepelmeme basins. The analyzed basins present similar tectono-sedimentary evolutions as follows: Stage 1, depocenter formation and filling by clastic rocks accumulated as alluvial fans and Stage 2, lacustrine sedimentation characterized by calcareous and/or evaporite beds. Based on our results, we propose the following hypothesis: in Southern Mexico, during Eocene-Miocene times, the diachronic formation of fault-bounded basins with general north-south trend occurred within the framework of the convergence between the plates of North and South America, and once the Chortís block had slipped towards the east, the basins formed in the cortical crust were recently left behind. On the other hand, the beginning of the basins' formation process related to left strike slip faults during Eocene-Oligocene times can be associated with the thermomechanical maturation cortical process that caused the brittle/ductile transition level in the continental crust to shallow.

  9. Deformation style and controlling geodynamic processes at the eastern Guadalquivir foreland basin (Southern Spain)

    Science.gov (United States)

    Marín-Lechado, C.; Pedrera, A.; Peláez, J. A.; Ruiz-Constán, A.; González-Ramón, A.; Henares, J.

    2017-06-01

    The tectonic structure of the Guadalquivir foreland basin becomes complex eastward evolving from a single depocenter to a compartmented basin. The deformation pattern within the eastern Guadalquivir foreland basin has been characterized by combining seismic reflection profiles, boreholes, and structural field data to output a 3-D model. High-dipping NNE-SSW to NE-SW trending normal and reverse fault arrays deform the Variscan basement of the basin. These faults generally affect Tortonian sediments, which show syntectonic features sealed by the latest Miocene units. Curved and S-shaped fault traces are abundant and caused by the linkage of nearby fault segments during lateral fault propagation. Preexisting faults were reactivated either as normal or reverse faults depending on their position within the foreland. At Tortonian time, reverse faults deformed the basin forebulge, while normal faults predominated within the backbulge. Along-strike variation of the Betic foreland basin geometry is supported by an increasing mechanical coupling of the two plates (Alborán Domain and Variscan basement) toward the eastern part of the cordillera. Thus, subduction would have progressed in the western Betics, while it would have failed in the eastern one. There, the initially subducted Iberian paleomargin (Nevado-Filábride Complex) was incorporated into the upper plate promoting the transmission of collision-related compressional stresses into the foreland since the middle Miocene. Nowadays, compression is still active and produces low-magnitude earthquakes likely linked to NNE-SSW to NE-SW preexiting faults reactivated with reverse oblique-slip kinematics. Seismicity is mostly concentrated around fault tips that are frequently curved in overstepping zones.

  10. Holocene and latest Pleistocene oblique dextral faulting on the southern Inyo Mountains fault, Owens Lake basin, California

    Science.gov (United States)

    Bacon, S.N.; Jayko, A.S.; McGeehin, J.P.

    2005-01-01

    The Inyo Mountains fault (IMF) is a more or less continuous range-front fault system, with discontinuous late Quaternary activity, at the western base of the Inyo Mountains in Owens Valley, California. The southern section of the IMF trends ???N20??-40?? W for at least 12 km at the base of and within the range front near Keeler in Owens Lake basin. The southern IMF cuts across a relict early Pliocene alluvial fan complex, which has formed shutter ridges and northeast-facing scarps, and which has dextrally offset, well-developed drainages indicating long-term activity. Numerous fault scarps along the mapped trace are northeast-facing, mountain-side down, and developed in both bedrock and younger alluvium, indicating latest Quaternary activity. Latest Quaternary multiple- and single-event scarps that cut alluvium range in height from 0.5 to 3.0 m. The penultimate event on the southern IMF is bracketed between 13,310 and 10,590 cal years B.P., based on radiocarbon dates from faulted alluvium and fissure-fill stratigraphy exposed in a natural wash cut. Evidence of the most recent event is found at many sites along the mapped fault, and, in particular, is seen in an ???0.5-m northeast-facing scarp and several right-stepping en echelon ???0.5-m-deep depressions that pond fine sediment on a younger than 13,310 cal years B.P. alluvial fan. A channel that crosses transverse to this scarp is dextrally offset 2.3 ?? 0.8 m, providing a poorly constrained oblique slip rate of 0.1-0. 3 m/ k.y. The identified tectonic geomorphology and sense of displacement demonstrate that the southern IMF accommodates predominately dextral slip and should be integrated into kinematic fault models of strain distribution in Owens Valley.

  11. 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...

  12. 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

  13. 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

  14. 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

  15. Analysis on groundwater evolution and interlayer oxidation zone position at the southern margin of Yilin basin

    International Nuclear Information System (INIS)

    Zhang Guanghui

    2007-01-01

    This paper discusses the development and evolution history of groundwater and its reworking to the interlayer oxidation zone, hydrogeochemical zonation of interlayer oxidation zone, mechanism of water-rock interaction and transportation pattern of uranium in the water in Yili Basin. It is suggested that groundwater is one of the important factors to control the development of interlayer oxidation zone and uranium mineralization. (authors)

  16. 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.

  17. Analysis on the geological features and ore-forming conditions at the southern margin of Erdos basin

    International Nuclear Information System (INIS)

    Ren Zhongxian; Shen Pingxi; Chen Fenling

    2014-01-01

    At the southern margin of Erdos basin, the paleo-interlayer-oxidation was developed in the medium-coarse-grained sandstone of Middle Jurassic System. High content uranium was enriched which are favorable for sandstone-type uranium deposit. There had been found multiple sandstone-type uranium deposits (ore occurrences) in this area. Uranium mineralization occurs in the sand body of braided fluvial facies in the lower member of Zhiluo Formation of Middle Jurassic System. It was controlled by the paleo-interlayer-oxidation. Uranium mineralization was closely related with the permeability of sandstone and occurs generally in the sandstones where is loose cementation and water permeability better. The stratum of Middle Jurassic System was extensively developed in the work area. Therefore it has great prospecting potential for the sandstone-type uranium deposit. (authors)

  18. Proterozoic structure, cambrian rifting, and younger faulting as revealed by a regional seismic reflection network in the Southern Illinois Basin

    Science.gov (United States)

    Potter, C.J.; Drahovzal, James A.; Sargent, M.L.; McBride, J.H.

    1997-01-01

    Four high-quality seismic reflection profiles through the southern Illinois Basin, totaling 245 km in length, provide an excellent regional subsurface stratigraphic and structural framework for evaluation of seismic risk, hydrocarbon occurrence, and other regional geologic studies. These data provide extensive subsurface information on the geometry of the intersection of the Cambrian Reelfoot and Rough Creek rifts, on extensive Proterozoic reflection sequences, and on structures (including the Fluorspar Area Fault Complex and Hicks Dome) that underlie a transitional area between the well-defined New Madrid seismic zone (to the southwest) and a more diffuse area of seismicity in the southern Illinois Basin. Our principal interpretations from these data are listed here in order of geologic age, from oldest to youngest: 1. Prominent Proterozoic layering, possibly equivalent to Proterozoic (???1 Ga) Middle Run Formation clastic strata and underlying (1.3-1.5 Ga) volcanic rocks of the East Continent rift basin, has been strongly deformed, probably as part of the Grenville foreland fold and thrust belt. 2. A well-defined angular unconformity is seen in many places between Proterozoic and Cambrian strata; a post-Grenville Proterozoic sequence is also apparent locally, directly beneath the base of the Cambrian. 3. We infer a major reversal in Cambrian rift polarity (accommodation zone) in the Rough Creek Graben in western Kentucky. 4. Seismic facies analysis suggests the presence of basin-floor fan complexes at and near the base of the Cambrian interval and within parts of a Proterozoic post-Grenville sequence in several parts of the Rough Creek Graben. 5. There is an abrupt pinchout of the Mount Simon Sandstone against crystalline basement beneath the Dale Dome (near the Texaco no. 1 Cuppy well, Hamilton County) in southeastern Illinois, and a more gradual Mount Simon pinchout to the southeast. 6. Where crossed by the seismic reflection line in southeast Illinois, some

  19. Euglossa williamsi, a new species of orchid bee from the Amazon Basin of Ecuador and Peru, with notes on its taxonomic association and biogeography (Hymenoptera, Apidae

    Directory of Open Access Journals (Sweden)

    Ismael Hinojosa-Díaz

    2011-12-01

    Full Text Available Euglossawilliamsi sp. n. is here described from the lowland Amazonianregion in Ecuador and Peru, and as part of a small species assemblage within Euglossa consisting of E. dodsoni Moure and E. obtusa Dressler. An identification key to the males of the group is provided plus detailed figures of the new species and representative illustrations for the others. A brief discussion of the taxonomic and biogeographical implications of the new species is provided. New records in Honduras and Nicaragua are provided for the related E. dodsoni.

  20. Hydrocarbon migration and accumulation in the Upper Cretaceous Qingshankou Formation, Changling Sag, southern Songliao Basin: Insights from integrated analyses of fluid inclusion, oil source correlation and basin modelling

    Science.gov (United States)

    Dong, Tian; He, Sheng; Wang, Dexi; Hou, Yuguang

    2014-08-01

    The Upper Cretaceous Qingshankou Formation acts as both the source and reservoir sequence in the Changling Sag, situated in the southern end of the Songliao Basin, northeast China. An integrated approach involving determination of hydrocarbon charging history, oil source correlation and hydrocarbon generation dynamic modeling was used to investigate hydrocarbon migration processes and further predict the favorable targets of hydrocarbon accumulations in the Qingshankou Formation. The hydrocarbon generation and charge history was investigated using fluid inclusion analysis, in combination with stratigraphic burial and thermal modeling. The source rocks began to generate hydrocarbons at around 82 Ma and the hydrocarbon charge event occurred from approximately 78 Ma to the end of Cretaceous (65.5 Ma) when a large tectonic uplift took place. Correlation of stable carbon isotopes of oils and extracts of source rocks indicates that oil was generated mainly from the first member of Qingshankou Formation (K2qn1), suggesting that hydrocarbon may have migrated vertically. Three dimensional (3D) petroleum system modeling was used to evaluate the processes of secondary hydrocarbon migration in the Qingshankou Formation since the latest Cretaceous. During the Late Cretaceous, hydrocarbon, mainly originated from the Qianan depression, migrated laterally to adjacent structural highs. Subsequent tectonic inversion, defined as the late Yanshan Orogeny, significantly changed hydrocarbon migration patterns, probably causing redistribution of primary hydrocarbon reservoirs. In the Tertiary, the Heidimiao depression was buried much deeper than the Qianan depression and became the main source kitchen. Hydrocarbon migration was primarily controlled by fluid potential and generally migrated from relatively high potential areas to low potential areas. Structural highs and lithologic transitions are potential traps for current oil and gas exploration. Finally, several preferred hydrocarbon

  1. Stratigraphic and structural relationships between Meso-Cenozoic Lagonegro basin and coeval carbonate platforms in southern Apennines, Italy

    Science.gov (United States)

    Pescatore, Tullio; Renda, Pietro; Schiattarella, Marcello; Tramutoli, Mariano

    1999-12-01

    Stratigraphic studies and facies analysis integrated with a new geological and structural survey of the Meso-Cenozoic units outcropping in the Campania-Lucania Apennines, southern Italy, allowed us to restore the palaeogeographic pattern and the tectonic evolution of the chain during Oligo-Miocene times. The southern Apennines are a N150°-striking and NE-verging fold-and-thrust belt mainly derived from the deformation of the African-Apulian passive margin. Four wide belts with different features have been recognized in the chain area. From east to west the following units outcrop: (a) successions characterized by basinal to marginal facies, ranging in age from Cretaceous to Miocene, tectonically lying on Plio-Pleistocene foredeep deposits; (b) successions characterized by shallow-water, basinal and shelf-margin facies, ranging in age from middle Triassic to Miocene ('Lagonegro units'), overthrust on the previous ones; (c) Triassic to Miocene carbonate platform successions ('Apenninic platform units'), overthrust on the Lagonegro units; (d) Jurassic-Cretaceous to Miocene deep-water successions (ophiolite-bearing or 'internal' units and associated siliciclastic wedges), outcropping along the Tyrrhenian belt and the Calabria-Lucania boundary, overthrust on the Apenninic platform units. All these units tectonically lie on the buried Apulian platform which is covered, at least in the eastern sector of the chain, by Pliocene to Pleistocene foredeep deposits. Stratigraphic patterns of the Cretaceous to lower Miocene Lagonegro successions are coherent with the platform margin ones. Calcareous clastics of the Lagonegro basin are in fact supplied by an adjacent western platform, as inferred by several sedimentological evidences (slump and palaeocurrent directions and decreasing grain size towards the depocentre of the basin). Tectonic relationships among the different units of the chain — with particular emphasis on the Lagonegro and Apenninic platform units of the

  2. 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.

  3. Regional gravity and magnetic surveys along southern margin of Indravati basin, Central India - a guide to unconformity related uranium mineralisation

    International Nuclear Information System (INIS)

    Patra, I.; Ramesh Babu, V.; Chaturvedi, A.K.; Sreenivas, R.; Chari, M.N.; Dash, J.K.; Roy, M.K.

    2009-01-01

    Geophysical methods play vital role at various stages in mineral exploration programme particularly in case of buried deposits. The unconformity related uranium deposits owing to their concealed nature are explored by geophysical methods as an indirect tool. Regional ground gravity and magnetic surveys have been conducted to decipher the basin configuration, presence of fault/ fractures and basic activity. These structural features may form favorable criteria for mineralisation. Qualitative and quantitative interpretation of the gravity and magnetic data along the southern margin of Mesoproterozoic Indravati basin has been correlated with ground follow up geological investigation. There exists a good correlation between interpreted faults, fracture zones and mafic activity from the magnetic and gravity surveys with available borehole data in the area. Further, 2D models generated from magnetic data have paved the way for planning boreholes and thereby reorienting the sub-surface exploration programme. Evidence of alteration and fracturing intercepted from the borehole correlates well with the low gravity and magnetic. Hence, gravity and magnetic surveys can be effectively utilized in delineating basement configuration and to estimate sediment thickness besides deciphering post sedimentary fault/fractures which are favorable factors for unconformity related uranium mineralisation. (author)

  4. 76 FR 10914 - Notice of Public Meetings: Mojave-Southern Great Basin Resource Advisory Council, Nevada

    Science.gov (United States)

    2011-02-28

    ... Area (NCA) Visitor's Center, Las Vegas, Nevada; July 21, 2011, at the BLM Southern Nevada District... final meeting agenda that will be available two weeks prior to each meeting. FOR FURTHER INFORMATION... be raised by RAC members. The final agendas with any additions/corrections to agenda topics...

  5. Geological factors controlling occurrence and distribution of arsenic in groundwaters from the southern margin of the Duero Basin, Spain.

    Science.gov (United States)

    Giménez-Forcada, Elena; Smedley, Pauline L

    2014-12-01

    Groundwater from springs and boreholes on the southern edge of the Cenozoic Duero Basin (DB) of Spain has concentrations of arsenic (As) which are commonly above the EC drinking-water limit of 10 μg/L and reach observed values up to 241 μg/L. Groundwater compositions within the sedimentary aquifer vary from Ca-HCO3 type, variably affected by evaporation and agricultural pollution at shallow levels, to Na-HCO3 compositions in deeper boreholes of the basin. Groundwater conditions are mainly oxidising, but reducing groundwaters exist in sub-basins within the aquifer, localised flow paths likely being influenced by basement structure. Arsenic concentrations are spatially variable, reaching up to 38 μg/L in springs of the Spanish Central System (SCS) basement aquifer and up to 62 μg/L in springs from the DB. Highest As concentrations are associated with the Na-HCO3 compositions in deep boreholes (200-450 m depth) within the DB. These have high pH values (up to 9.6) which can give rise to associated elevated concentrations of V and U (up to 64 and 30 μg/L, respectively). In the deep borehole waters of the DB, oxidising flows derived from the mineralised igneous-metamorphic basement and discharging via major faults, and are considered the origin of the higher concentrations. Compositions are consistent with desorption of As and other anionic species from metal oxyhydroxides in an oxic environment. Under locally reducing conditions prevalent in some low-flow parts of the DB, an absence of detectable dissolved As is coincident with low or undetectable SO4 concentrations, and consistent with loss via formation of authigenic sulphide minerals. Mitigation measures are needed urgently in this semi-arid region where provision of alternative sources of safe drinking water is logistically difficult and expensive.

  6. 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.

  7. Evaluation of genotoxicity and cytotoxicity of water samples from the Sinos River Basin, southern Brazil

    Directory of Open Access Journals (Sweden)

    E Bianchi

    Full Text Available Some water bodies in the Sinos River Basin (SRB have been suffering the effects of pollution by residential, industrial and agroindustrial wastewater. The presence of cytotoxic and genotoxic compounds could compromise the water quality and the balance of these ecosystems. In this context, the research aimed to evaluate the genotoxicity and cytotoxicity of the water at four sites along the SRB (in the cities of Santo Antônio da Patrulha, Parobé, Campo Bom and Esteio, using bioassays in fish and cell culture. Samples of surface water were collected and evaluated in vitro using the Astyanax jacuhiensis fish species (micronucleus test and comet assay and the Vero lineage of cells (comet assay and cytotoxicity tests, neutral red - NR and tetrazolium MTT. The micronucleus test in fish showed no significant differences between the sampling sites, and neither did the comet assay and the MTT and NR tests in Vero cells. The comet assay showed an increase in genetic damage in the fish exposed to water samples collected in the middle and lower sections of the basin (Parobé, Campo Bom and Esteio when compared to the upper section of the basin (Santo Antônio da Patrulha. The results indicate contamination by genotoxic substances starting in the middle section of the SRB.

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

    International Nuclear Information System (INIS)

    Masoudi, M.; Asrari, E.

    2009-01-01

    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.

  9. Early evolution of the southern margin of the Neuquén Basin, Argentina: Tectono-stratigraphic implications for rift evolution and exploration of hydrocarbon plays

    Science.gov (United States)

    D'Elia, Leandro; Bilmes, Andrés; Franzese, Juan R.; Veiga, Gonzalo D.; Hernández, Mariano; Muravchik, Martín

    2015-12-01

    Long-lived rift basins are characterized by a complex structural and tectonic evolution. They present significant lateral and vertical stratigraphic variations that determine diverse basin-patterns at different timing, scale and location. These issues cause difficulties to establish facies models, correlations and stratal stacking patterns of the fault-related stratigraphy, specially when exploration of hydrocarbon plays proceeds on the subsurface of a basin. The present case study corresponds to the rift-successions of the Neuquén Basin. This basin formed in response to continental extension that took place at the western margin of Gondwana during the Late Triassic-Early Jurassic. A tectono-stratigraphic analysis of the initial successions of the southern part of the Neuquén Basin was carried out. Three syn-rift sequences were determined. These syn-rift sequences were located in different extensional depocentres during the rifting phases. The specific periods of rifting show distinctly different structural and stratigraphic styles: from non-volcanic to volcanic successions and/or from continental to marine sedimentation. The results were compared with surface and subsurface interpretations performed for other depocentres of the basin, devising an integrated rifting scheme for the whole basin. The more accepted tectono-stratigraphic scheme that assumes the deposits of the first marine transgression (Cuyo Cycle) as indicative of the onset of a post-rift phase is reconsidered. In the southern part of the basin, the marine deposits (lower Cuyo Cycle) were integrated into the syn-rift phase, implying the existence of different tectonic signatures for Cuyo Cycle along the basin. The rift climax becomes younger from north to south along the basin. The post-rift initiation followed the diachronic ending of the main syn-rift phase throughout the Neuquén Basin. Thus, initiation of the post-rift stage started in the north and proceeded towards the south, constituting a

  10. 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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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 3 type or the Ca–Na–HCO 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 analysed

  12. 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

  13. Water resource planning and water quality in the Riu Cixerri Basin (Southern Sardinia)

    International Nuclear Information System (INIS)

    Coni, M.; Ferralis, M; Madonia, P.; Sechi, C.; Verde, C.

    2000-01-01

    Present paper deals with a hydrogeological and biological study of the Riu Cixerri watershed (Southern Sardinia), carried out in order to evaluate volumes and quality of surface waters. Variables of hydrogeological balance have been derived by the use of a G.I.S. based method. The obtained results underline the low reliability of data used for past water resource planning and the good self purification capability of the Cixerri river [it

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

    International Nuclear Information System (INIS)

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

    2009-01-01

    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

  15. Origin of Boron and Brine Evolution in Saline Springs in the Nangqen Basin, Southern Tibetan Plateau

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    Ji-long Han

    2018-01-01

    Full Text Available The Nangqen Basin is a typical shearing-extensional basin situated in the hinterland of the Tibetan Plateau. It contains abundant saline spring resources and abnormal trace element enrichments. The hydrochemical molar ratios (Na/Cl, B/Cl, and Br/Cl, H-O isotopes, and B isotopes of the saline spring were systematically measured to describe the evolution of brines and the origin of the boron. The sodium chloride coefficient of the water samples in this area is around 1.0 or slightly greater, which is characteristic of leached brines; the highest B/Cl value is 4.25 (greater than that of seawater. The Na/Cl, B/Cl, and Br/Cl values of the springs are clear indicators of a crustal origin. The δ18O values of the spring waters range from −12.88‰ to −16.05‰, and the δD values range from −100.91‰ to −132.98‰. Meanwhile the B content and B isotopes in the saline springs are in the ranges of 1.00 to 575.56 ppm and +3.55‰ to +29.59‰, respectively. It has been proven that the saline springs in the Nangqen Basin are a type of leached brine, suggesting that the saline springs have a terrestrial origin. The δ11B-B characteristics of the springs are similar to those observed in the Tibetan geothermal area, indicating that these two places have the same B source. Moreover, they have a crustal origin (marine carbonate rocks and volcanic rocks instead of a deep mantle source.

  16. Neogene paleoelevation of intermontane basins in a narrow, compressional mountain range, southern Central Andes of Argentina

    Science.gov (United States)

    Hoke, Gregory D.; Giambiagi, Laura B.; Garzione, Carmala N.; Mahoney, J. Brian; Strecker, Manfred R.

    2014-11-01

    The topographic growth of mountain ranges at convergent margins results from the complex interaction between the motion of lithospheric plates, crustal shortening, rock uplift and exhumation. Constraints on the timing and magnitude of elevation change gleaned from isotopic archives preserved in sedimentary sequences provide insight into how these processes interact over different timescales to create topography and potentially decipher the impact of topography on atmospheric circulation and superposed exhumation. This study uses stable isotope data from pedogenic carbonates collected from seven different stratigraphic sections spanning different tectonic and topographic positions in the range today, to examine the middle to late Miocene history of elevation change in the central Andes thrust belt, which is located immediately to the south of the Altiplano-Puna Plateau, the world's second largest orogenic plateau. Paleoelevations are calculated using previously published local isotope-elevation gradients observed in modern rainfall and carbonate-formation temperatures determined from clumped isotope studies in modern soils. Calculated Neogene basin paleoelevations are between 1 km and 1.9 km for basins that today are located between 1500 and 3400 m elevation. Considering the modern elevation and δ18O values of precipitation at the sampling sites, three of the intermontane basins experienced surface uplift between the end of deposition during the late Miocene and present. The timing of elevation change cannot be linked to any documented episodes of large-magnitude crustal shortening. Paradoxically, the maximum inferred surface uplift in the core of the range is greatest where the crust is thinnest. The spatial pattern of surface uplift is best explained by eastward migration of a crustal root via ductile deformation in the lower crust and is not related to flat-slab subduction.

  17. Sedimentologic development of a Late Oligocene Miocene forearc embayment, Valdivia Basin Complex, southern Chile

    Science.gov (United States)

    le Roux, J. P.; Elgueta, Sara

    2000-01-01

    Deposition of Tertiary sediments in the southeastern part of the Valdivia Basin commenced during the Late Oligocene with the rapid incision of rivers draining the Palaeo-Coastal Range. Alluvial fans developing along the steep valley flanks joined gravelly braided streams transporting bedload to the coast. Tectonic and eustatic stability lasting into the Early Miocene subsequently allowed lateral erosion of the valley flanks and the development of extensive fluvial and estuarine peat swamps. This stable period was interrupted briefly by a volcanic eruption at 23.5 Ma. Shortly after 23 Ma, rapid uplift caused by an acceleration in plate convergence resulted in renewed erosion of the landscape, as reflected in the deposition of coarse river gravels. Basin subsidence and marine transgression proceeding up the river valleys subsequently formed still, deep embayments, occasionally disturbed by debris flows and turbidity currents originating on the steep, wooded valley flanks. At the upper limits of the inlets, bayhead deltas, tidal flats and beaches existed. In some areas, fan deltas prograded into the embayments, as reflected in the interfingering relationship between conglomerates and marine mudrocks. In the deeper parts of the embayments, the frequency of debris flows and turbidity currents increased markedly during periods of relative sea-level lowstand. The landscape was eventually inundated by continued subsidence and marine transgression, which lasted until a possibly eustatic sea-level fall in the early Tortonian.

  18. Consumptive Water Use Analysis of Upper Rio Grande Basin in Southern Colorado.

    Science.gov (United States)

    Dubinsky, Jonathan; Karunanithi, Arunprakash T

    2017-04-18

    Water resource management and governance at the river basin scale is critical for the sustainable development of rural agrarian regions in the West. This research applies a consumptive water use analysis, inspired by the Water Footprint methodology, to the Upper Rio Grande Basin (RGB) in south central Colorado. The region is characterized by water stress, high dessert conditions, declining land health, and a depleting water table. We utilize region specific data and models to analyze the consumptive water use of RGB. The study reveals that, on an average, RGB experiences three months of water shortage per year due to the unsustainable extraction of groundwater (GW). Our results show that agriculture accounts for 77% of overall water consumption and it relies heavily on an aquifer (about 50% of agricultural consumption) that is being depleted over time. We find that, even though potato cultivation provides the most efficient conversion of groundwater resources into economic value (m 3 GW/$) in this region, it relies predominantly (81%) on the aquifer for its water supply. However, cattle, another important agricultural commodity produced in the region, provides good economic value but also relies significantly less on the aquifer (30%) for water needs. The results from this paper are timely to the RGB community, which is currently in the process of developing strategies for sustainable water management.

  19. 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)

    Bedregal, P.S.; Mendoza, P.A.; Ubillus, M.S.; Montoya, E.H.; Jennings, J.

    2015-01-01

    Fragments of archaeological pottery from a rescue excavation at the site of La Real in Arequipa, Peru, were studied by instrumental neutron activation analysis, k 0 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)

  20. Groundwater quality in the shallow aquifers of the Tulare, Kaweah, and Tule Groundwater Basins and adjacent highlands areas, Southern San Joaquin Valley, California

    Science.gov (United States)

    Fram, Miranda S.

    2017-01-18

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. The shallow aquifers of the Tulare, Kaweah, and Tule groundwater basins and adjacent highlands areas of the southern San Joaquin Valley constitute one of the study units being evaluated.

  1. Prevalence and risk factors for encephalomyocarditis virus infection in Peru.

    Science.gov (United States)

    Czechowicz, Josephine; Huaman, Jose Luis; Forshey, Brett M; Morrison, Amy C; Castillo, Roger; Huaman, Alfredo; Caceda, Roxana; Eza, Dominique; Rocha, Claudio; Blair, Patrick J; Olson, James G; Kochel, Tadeusz J

    2011-04-01

    Although encephalomyocarditis virus (EMCV) infection has been commonly documented among domestic animals, less is known about EMCV transmission among humans. Recently, we described the isolation of EMCV from two febrile patients in Peru. To further investigate EMCV transmission in Peru, we screened febrile patients reporting to health clinics in Peru for serological evidence of recent EMCV infection. We also conducted a serological survey for EMCV-neutralizing antibodies in the city of Iquitos, located in the Amazon basin department of Loreto, Peru. Additionally, we screened serum from rodents collected from 10 departments in Peru for evidence of EMCV exposure. EMCV infection was found to be only rarely associated with acute febrile disease in Peru, accounting for 17% in cities in the tropical rainforest of northeastern Peru (Iquitos and Yurimaguas). On the basis of the serological survey conducted in Iquitos, risk factors for past infection include increased age, socioeconomic indicators such as residence construction materials and neighborhood, and swine ownership. Evidence from the rodent survey indicates that EMCV exposure is common among Murinae subfamily rodents in Peru (9.4% EMCV IgG positive), but less common among Sigmodontinae rodents (1.0% positive). Further studies are necessary to more precisely delineate the mode of EMCV transmission to humans, other potential disease manifestations, and the economic impact of EMCV transmission among swine in Peru.

  2. International Uranium Resources Evaluation Project (IUREP) orientation phase mission summary report: Peru

    International Nuclear Information System (INIS)

    1984-01-01

    A report has recently been published which describes the findings of the International Uranium Resources Evaluation Project (TUREP) Mission to Peru. The IUREP Orientation Phase Mission to Peru estimates that the Speculative Resources of that country fall within the range of 6 000 to 11 000 tonnes uranium. The majority of this potential is expected to be located in Late Tertiary ignimbrites and associated sediments in the high Andes of southern Peru. Other favourable geological environments include calcretes, developed from Tertiary volcanogenic sources over the Precambrian in the Pacific Coastal desert in southern Peru, and Hercynian subvolcanic granites in the eastern Cordillera of southern Peru. The Mission recommends that over a period of five years approximately U.S. $10 million be spent on exploration in Peru. The majority of this would be spent on drilling ($5 million) and tunnelling ($2 million) with an additional $3 million on surface and airborne radiometric surveys. (author)

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

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    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.

  4. Geology and geochemistry of endoroique basin case of Baghdad chott southern of Algeria

    Science.gov (United States)

    Lamini, Abdellah; Hacini, Messaoud

    2018-05-01

    Chott Baghdad is an inland saline lake of the type Na-(Mg)-CI-(SO4). It is situated in septontrional Algerian sahara basin (northern of Africa).these small depression is fall dawn about 31m below sea level. One of characteristic of this zone is dry climate in summer when temperature reach 45°C and decrease in winter 5 °C. Chott Baghdad irrigate with surface water zone, continental saharan aquifer and precipitated water. Evaporative lakes without river outlets are common and their chemical composition has been reported to exhibit a wide diversity (Hardie and Eugster, 1970; Eugster and Hardie, 1978). Geologics and gitologic characteristics of deposed evaporates in Baghdad basin, small closed lagon take place with brines rich in ions SO42 - , Ca2+, Na+, Cl- and under the effect of evaporation generate the rock salt and gypsum precipitation. The objective of this study is to simulate evolution the geochemical cycle inside of chott Baghdad, in addition try to interpreter behavior of major element which constructs this small depression. The most important thing is to calculate saturated index of evaporated mineral and compare it with DRX result. To reach this study, monthly brine samples were collected from January to December. Different analytic methods were used: physico-chemical analytic (PH, temperature and conductivity). In addition, spectrophotometer and titration, phlameemissions were done to calculate major element concentration. From this study, we can conclude that major element behavior (Na+, Cl-, SO42 - , Mg+, K+, HCO3-, and Ca2+) is as follow: Chlore and sodium was decreasing at end of geochemical cycle. In addition, Bicarbonate, potassium and magnesium have characteristic evolution, where they increase at the beginning of geochemical cycle till summer then decrease steadily at the end of cycle. Where us, Calcium is quit steady during one year cycle.

  5. Simulation of Regional Ground-Water Flow in the Suwannee River Basin, Northern Florida and Southern Georgia

    Science.gov (United States)

    Planert, Michael

    2007-01-01

    The Suwannee River Basin covers a total of nearly 9,950 square miles in north-central Florida and southern Georgia. In Florida, the Suwannee River Basin accounts for 4,250 square miles of north-central Florida. Evaluating the impacts of increased development in the Suwannee River Basin requires a quantitative understanding of the boundary conditions, hydrogeologic framework and hydraulic properties of the Floridan aquifer system, and the dynamics of water exchanges between the Suwannee River and its tributaries and the Floridan aquifer system. Major rivers within the Suwannee River Basin are the Suwannee, Santa Fe, Alapaha, and Withlacoochee. Four rivers west of the Suwannee River are the Aucilla, the Econfina, the Fenholloway, and the Steinhatchee; all drain to the Gulf of Mexico. Perhaps the most notable aspect of the surface-water hydrology of the study area is that large areas east of the Suwannee River are devoid of channelized, surface drainage; consequently, most of the drainage occurs through the subsurface. The ground-water flow system underlying the study area plays a critical role in the overall hydrology of this region of Florida because of the dominance of subsurface drain-age, and because ground-water flow sustains the flow of the rivers and springs. Three principal hydrogeologic units are present in the study area: the surficial aquifer system, the intermediate aquifer system, and the Floridan aquifer system. The surficial aquifer system principally consists of unconsoli-dated to poorly indurated siliciclastic deposits. The intermediate aquifer system, which contains the intermediate confining unit, lies below the surficial aquifer system (where present), and generally consists of fine-grained, uncon-solidated deposits of quartz sand, silt, and clay with interbedded limestone of Miocene age. Regionally, the intermediate aquifer system and intermediate con-fining unit act as a confining unit that restricts the exchange of water between the over

  6. [US Geological Survey research in radioactive waste disposal, fiscal year 1980:] Tectonics, seismicity, volcanism, and erosion rates in the southern Great Basin

    International Nuclear Information System (INIS)

    Carr, W.J.; Rogers, A.M.

    1982-01-01

    The objective is to assess the potential for faulting, damaging earthquakes, recurrence of volcanism, and local acceleration of erosion in parts of the southern Great Basin. The following approaches are being used: (1) investigating the rate, intensity, and distribution of faulting during approximately the last 25 m.y., with emphasis on the last 10 m.y.; (2) monitoring and interpreting present seismicity; (3) studying the history of volcanism; and (4) evaluating past rates of erosion and deposition. Progress is reported

  7. Folded Basinal Compartments of the Southern Mongolian Borderland: A Structural Archive of the Final Consolidation of the Central Asian Orogenic Belt

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    Dickson Cunningham

    2017-01-01

    Full Text Available The Central Asian Orogenic Belt (CAOB records multiple Phanerozoic tectonic events involving consolidation of disparate terranes and cratonic blocks and subsequent reactivation of Eurasia’s continental interior. The final amalgamation of the CAOB terrane collage involved diachronous closure of the Permian-Triassic Solonker suture in northernmost China and the Jurassic Mongol-Okhotsk suture in northeast Mongolia and eastern Siberia. The distribution, style, and kinematics of deformation associated with these two terminal collision events is poorly documented in southern Mongolia and northernmost China because these regions were later tectonically overprinted by widespread Cretaceous basin and range-style crustal extension and Miocene-recent sinistral transpressional mountain building. These younger events structurally compartmentalized the crust into uplifted crystalline basement blocks and intermontane basins. Consequently, widespread Cretaceous and Late Cenozoic clastic sedimentary deposits overlie older Permian-Jurassic sedimentary rocks in most basinal areas and obscure the deformation record associated with Permian-Triassic Solonker and Jurassic Mongol-Okhotsk collisional suturing. In this report, satellite image mapping of basinal compartments that expose folded Permian-Jurassic sedimentary successions that are unconformably overlapped by Cretaceous-Quaternary clastic sediments is presented for remote and poorly studied regions of southern Mongolia and two areas of the Beishan. The largest folds are tens of kilometers in strike length, east-west trending, and reveal north-south Late Jurassic shortening (present coordinates. Late Jurassic fold vergence is dominantly northerly in the southern Gobi Altai within a regional-scale fold-and-thrust belt. Local refolding of older Permian north-south trending folds is also evident in some areas. The folds identified and mapped in this study provide new evidence for the regional distribution and

  8. River-Basin Politics and the Rise of Ecological and Transnational Democracy in Southeast Asia and Southern Africa

    Directory of Open Access Journals (Sweden)

    Chris Sneddon

    2008-06-01

    Full Text Available In recent years, debates over 'deliberative', 'transnational' and 'ecological' democracy have proliferated, largely among scholars engaged in discussions of modernisation, globalisation and political identity. Within this broad context, scholars and practitioners of environmental governance have advanced the argument that a democratic society will produce a more environmentally conscious society. We want to make a volte-face of this argument and ask: to what extent does engagement with environmental politics and, specifically, water politics, contribute to processes of democratisation? After reviewing some of the contributions to debates over 'ecological' and 'transnational' democracy, we explore this question within the context of conflicts over river-basin development in Southeast Asia and southern Africa. We argue that there are multiple pathways to democratisation and that, in some cases, the environment as a political issue does constitute a significant element of democratisation. But notions of 'ecological' and 'transnational' democracy must embody how both 'environment' and 'the transnational', as mobilised by specific social movements in specific historical and geographical circumstances, are politically constructed.

  9. Soil response to long-term projections of extreme temperature and precipitation in the southern La Plata Basin

    Science.gov (United States)

    Pántano, Vanesa C.; Penalba, Olga C.

    2017-12-01

    Projected changes were estimated considering the main variables which take part in soil-atmosphere interaction. The analysis was focused on the potential impact of these changes on soil hydric condition under extreme precipitation and evapotranspiration, using the combination of Global Climate Models (GCMs) and observational data. The region of study is the southern La Plata Basin that covers part of Argentine territory, where rainfed agriculture production is one of the most important economic activities. Monthly precipitation and maximum and minimum temperatures were used from high quality-controlled observed data from 46 meteorological stations and the ensemble of seven CMIP5 GCMs in two periods: 1970-2005 and 2065-2100. Projected changes in monthly effective temperature and precipitation were analysed. These changes were combined with observed series for each probabilistic interval. The result was used as input variables for the water balance model in order to obtain consequent soil hydric condition (deficit or excess). Effective temperature and precipitation are expected to increase according to the projections of GCMs, with few exceptions. The analysis revealed increase (decrease) in the prevalence of evapotranspiration over precipitation, during spring (winter). Projections for autumn months show precipitation higher than potential evapotranspiration more frequently. Under dry extremes, the analysis revealed higher projected deficit conditions, impacting on crop development. On the other hand, under wet extremes, excess would reach higher values only in particular months. During December, projected increase in temperatures reduces the impact of extreme high precipitation but favours deficit conditions, affecting flower-fructification stage of summer crops.

  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. An organic geochemical correlation study of some Drmno depresssion crude oils (southern part of the Pannonian Basin, Yugoslavia

    Directory of Open Access Journals (Sweden)

    D. VITOROVIC

    2001-05-01

    Full Text Available The results of an investigation of crude oils originating from the Sirakovo and Bradarac-Maljurevac localities (southern part of the Pannonian Basin are reported in this paper. The aim was to estimate the organic geochemical similarity of the crude oils from the Drmno (Kostolac depression oil fields. The nine selected samples originated from reservoir rocks of various depths. Reliable source and organic geochemical maturation parameters served as the basis for the correlation studies. The similar origin of the investigated Drmno depression crude oils was corroborated, characterized by a significant participation of terrestrial precursor biomass. They were shown to be of relatively low maturity and to have been formed during the earlier stages of the diagenet- ic-catagenetic sequence of processes leading to the formation of crude oils, most probably in source rocks ofTertiary age, corresponding to vitrinite reflectances between Ro = 0.70 % and Ro = 0.80 %. The crude oils from Bradarac-Maljurevac seemed to be somewhat less homogeneous with respect to organic geochemical parameters compared to Sirakovo crude oils.

  12. Historical Evolution of the Hydrological Functioning of the Old Lake Xochimilco, Southern Mexico Basin

    Science.gov (United States)

    Gonzalez, T.; Ruvalcaba, A.

    2012-12-01

    The lacustrian area of Xochimilco is one of the remnants of the old system of lakes located in the Basin of Mexico. After the Spanish conquest, began a series of actions including hydraulic-works that have changed the original landscape of this region. This region had important springs that for more than 50 years supplied water to the Mexico City. Since 1960, the excessive exploitation of the aquifer and urban growth in the region exhausted the springs. Using historical information we were able to characterize the major phenomena that have substantially changed the hydrogeological functioning of the region, in some more than 100 years. Currently, the exploitation of extraction wells has caused a gradual decrease in their static level and the existing remnant of the old lake is maintained with treated water. Observable effects are presented. The topographic gradient has been modified occurs subsidence and fractures are visible besides a severe reduction in the lake area which has been reduced to 15% of its original extent.

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

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    CM Furtado

    Full Text Available 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.

  14. Late quaternary dynamics in the Madeira river basin, southern Amazonia (Brazil, as revealed by paleomorphological analysis

    Directory of Open Access Journals (Sweden)

    Ericson H. Hayakawa

    2015-03-01

    Full Text Available Ancient drainage systems are being increasingly documented in the Amazon basin and their characterization is crucial for reconstructing fluvial evolution in this area. Fluvial morphologies, including elongate belts, are well preserved along the Madeira River. Digital Elevation Model from the Shuttle Radar Topography Mission favored the detection of these features even where they are covered by dense rainforest. These paleomorphologies are attributed to the shifting position of past tributaries of the Madeira River through avulsions. These radial paleodrainage networks produced fan-shaped morphologies that resemble distributary megafans. Distinguishing avulsive tributary systems from distributary megafans in the sedimentary record is challenging. Madeira´s paleodrainage reveals the superposition of tributary channels formed by multiple avulsions within a given time period, rather than downstream bifurcation of coexisting channels. Channel avulsion in this Amazonian area during the late Quaternary is related to tectonics due to features as: (i straight lineaments coincident with fault directions; (ii northeastward tilting of the terrain with Quaternary strata; and (iii several drainage anomalies, including frequent orthogonal drainage inflections. These characteristics altogether lead to propose that the radial paleodrainage present at the Madeira River margin results from successive avulsions of tributary channels over time due to tectonics.

  15. Emergency Assessment of Debris-Flow Hazards from Basins Burned by the 2007 Ranch Fire, Ventura and Los Angeles Counties, Southern California

    Science.gov (United States)

    Cannon, Susan H.; Gartner, Joseph E.; Michael, John A.; Bauer, Mark A.; Stitt, Susan C.; Knifong, Donna L.; McNamara, Bernard J.; Roque, Yvonne M.

    2007-01-01

    INTRODUCTION The objective of this report is to present a preliminary emergency assessment of the potential for debris-flow generation from basins burned by the Ranch Fire in Ventura and Los Angeles Counties, southern California in 2007. Debris flows are among the most hazardous geologic phenomena; debris flows that followed wildfires in southern California in 2003 killed 16 people and caused tens of millions of dollars of property damage. A short period of even moderate rainfall on a burned watershed can lead to debris flows. Rainfall that is normally absorbed into hillslope soils can run off almost instantly after vegetation has been removed by wildfire. This causes much greater and more rapid runoff than is normal from creeks and drainage areas. Highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud, boulders, and unburned vegetation. Within the burned area and downstream, the force of rushing water, soil, and rock can destroy culverts, bridges, roadways, and buildings, potentially causing injury or death. This emergency debris-flow hazard assessment is presented as relative ranking of the predicted median volume of debris flows that can issue from basin outlets in response to 2.25 inches (57.15 mm) of rainfall over a 3-hour period. Such a storm has a 10-year return period. The calculation of debris flow volume is based on a multiple-regression statistical model that describes the median volume of material that can be expected from a recently burned basin as a function of the area burned at high and moderate severity, the basin area with slopes greater than or equal to 30 percent, and triggering storm rainfall. Cannon and others (2007) describe the methods used to generate the hazard maps. Identification of potential debris-flow hazards from burned drainage basins is necessary to issue warnings for specific basins, to make effective mitigation decisions, and to help plan evacuation timing and routes.

  16. Emergency Assessment of Debris-Flow Hazards from Basins Burned by the 2007 Slide and Grass Valley Fires, San Bernardino County, Southern California

    Science.gov (United States)

    Cannon, Susan H.; Gartner, Joseph E.; Michael, John A.; Bauer, Mark A.; Stitt, Susan C.; Knifong, Donna L.; McNamara, Bernard J.; Roque, Yvonne M.

    2007-01-01

    INTRODUCTION The objective of this report is to present a preliminary emergency assessment of the potential for debris-flow generation from basins burned by the Slide and Grass Valley Fires in San Bernardino County, southern California in 2007. Debris flows are among the most hazardous geologic phenomena; debris flows that followed wildfires in southern California in 2003 killed 16 people and caused tens of millions of dollars of property damage. A short period of even moderate rainfall on a burned watershed can lead to debris flows. Rainfall that is normally absorbed into hillslope soils can run off almost instantly after vegetation has been removed by wildfire. This causes much greater and more rapid runoff than is normal from creeks and drainage areas. Highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud, boulders, and unburned vegetation. Within the burned area and downstream, the force of rushing water, soil, and rock can destroy culverts, bridges, roadways, and buildings, potentially causing injury or death. This emergency debris-flow hazard assessment is presented as relative ranking of the predicted median volume of debris flows that can issue from basin outlets in response to 3.50 inches (88.90 mm) of rainfall over a 3-hour period. Such a storm has a 10-year return period. The calculation of debris flow volume is based on a multiple-regression statistical model that describes the median volume of material that can be expected from a recently burned basin as a function of the area burned at high and moderate severity, the basin area with slopes greater than or equal to 30 percent, and triggering storm rainfall. Cannon and others (2007) describe the methods used to generate the hazard maps. Identification of potential debris-flow hazards from burned drainage basins is necessary to issue warnings for specific basins, to make effective mitigation decisions, and to help plan evacuation timing and routes.

  17. Tetrapod tracks in Permo–Triassic eolian beds of southern Brazil (Paraná Basin

    Directory of Open Access Journals (Sweden)

    Heitor Francischini

    2018-05-01

    Full Text Available Tetrapod tracks in eolianites are widespread in the fossil record since the late Paleozoic. Among these ichnofaunas, the ichnogenus Chelichnus is the most representative of the Permian tetrapod ichnological record of eolian deposits of Europe, North America and South America, where the Chelichnus Ichnofacies often occurs. In this contribution, we describe five sets of tracks (one of which is preserved in cross-section, representing the first occurrence of Dicynodontipus and Chelichnus in the “Pirambóia Formation” of southern Brazil. This unit represents a humid desert in southwestern Pangea and its lower and upper contacts lead us to consider its age as Lopingian–Induan. The five sets of tracks studied were compared with several ichnotaxa and body fossils with appendicular elements preserved, allowing us to attribute these tracks to dicynodonts and other indeterminate therapsids. Even though the “Pirambóia Formation” track record is sparse and sub-optimally preserved, it is an important key to better understand the occupation of arid environments by tetrapods across the Permo–Triassic boundary.

  18. Interannual variation of the South China Sea circulation during winter: intensified in the southern basin

    Science.gov (United States)

    Zu, Tingting; Xue, Huijie; Wang, Dongxiao; Geng, Bingxu; Zeng, Lili; Liu, Qinyan; Chen, Ju; He, Yunkai

    2018-05-01

    Surface geostrophic current derived from altimetry remote sensing data, and current profiles observed from in-situ Acoustic Doppler Current Profilers (ADCP) mooring in the northern South China Sea (NSCS) and southern South China Sea (SSCS) are utilized to study the kinetic and energetic interannual variability of the circulation in the South China Sea (SCS) during winter. Results reveal a more significant interannual variation of the circulation and water mass properties in the SSCS than that in the NSCS. Composite ananlysis shows a significantly reduced western boundary current (WBC) and a closed cyclonic eddy in the SSCS at the mature phase of El Niño event, but a strong WBC and an unclosed cyclonic circulation in winter at normal or La Niña years. The SST is warmer while the subsurface water is colder and fresher in the mature phase of El Niño event than that in the normal or La Niña years in the SSCS. Numerical experiments and energy analysis suggest that both local and remote wind stress change are important for the interannual variation in the SSCS, remote wind forcing and Kuroshio intrusion affect the circulation and water mass properties in the SSCS through WBC advection.

  19. Amazon river basin evapotranspiration and its influence on the rainfall in southern Brazil

    Science.gov (United States)

    Folegatti, M. V.; Wolff, W.

    2017-12-01

    Amazon river basin (ARB) presents a positive water balance, i.e. the precipitation is higher than evapotranspiration. Regarding the regional circulation, ARB evapotranspiration represents an important source of humidity for the South of Brazil. Thus, the aim of this work is to answer the question: how much is the correlation between ARB evapotranspiration and rainfall in South of Brazil? The shapefiles data of ARB and countries/states boundary were obtained through the Oak Ridge National Laboratory (ORNL) and Instituto Brasileiro de Geografia e Estatística (IBGE), respectively. According to rasters data, the precipitation was obtained from study of Numerical Terradynamic Simulation Group (NTSG) for images of Moderate Resolution Imaging Spectroradiometer (MODIS), under code MOD16A2, whereas rasters data for evapotranspiration were obtained from National Aeronautics and Space Administration (NASA) by Tropical Rainfall Measuring Mission Multi-Satellite Precipitation Analysis (TMPA), under code 3B43_V7. The products MOD16A2 and 3B43_V7 have a respective spatial resolution of 0.5º and 0.25º, and a monthly temporal resolution from January/2000 to December/2014. For ARB and South region of Brazil was calculated the mean evapotranspiration and mean precipitation through the pixels within of the respective polygons. To answer the question of this work was performed the cross-correlation analysis between these time series. We observed the highest value for the lag that corresponds the begin of spring (October), being 0.3 approximately. As a result, the mean precipitation on South region of Brazil during spring and summer was in the order of 15% to 30 %, explained by ARB evapotranspiration. For this reason, the maintenance of ARB is extremely important for water resource grant in South of Brazil.

  20. 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.

  1. Regional hydrology of the Blanding-Durango area, southern Paradox Basin, Utah and Colorado

    International Nuclear Information System (INIS)

    Whitfield, M.S. Jr.; Thordarson, W.; Oatfield, W.J.; Zimmerman, E.A.; Rueger, B.F.

    1983-01-01

    Principal findings of this study that are pertinent to an assessment of suitability of the hydrogeologic systems to store and contain radioactive waste in salt anticlines of adjacent areas are: water in the upper ground-water flow system discharges to the San Juan River - a major tributary of the Colorado River. Discharge of water from the upper aquifer system to streambed channels of the San Juan River and its tributaries during low-flow periods primarily is through evapotranspiration from areas on flood plains and maintenance of streamflow; the lower ground-water system does not have known recharge or discharge areas within the study area; subsurface inflow to this system comes from recharge areas located north and northeast of the study area; the upper and lower ground-water systems are separated regionally by thick salt deposits in the Blanding-Durango study area of the Paradox basin; potential exists in mountainous areas for downward leakage between the upper and lower ground-water systems, where salt deposits are thin, absent, or faulted; no brines were found in this study area with outflow to the biosphere; water in the upper ground-water system generally is fresh. Water in the lower ground-water system generally is brackish or saline; and ground-water flow disruptions by contiguous faults probably are common in the upper ground-water system. These disruptions of flow are not apparent in the lower ground-water system, perhaps because available hydrologic data for the lower ground-water system are scarce. The above major findings do not preclude the potential for waste storage in salt; however, they do not allow the prediction of detailed ground-water flow rates and directions through this area. 55 references, 13 figures, 15 tables

  2. 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.

  3. Peru action simmering despite privatization delays

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    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

  4. Architecture of a low-angle normal fault zone, southern Basin and Range (SE California)

    Science.gov (United States)

    Goyette, J. A.; John, B. E.; Campbell-Stone, E.; Stunitz, H.; Heilbronner, R.; Pec, M.

    2009-12-01

    Exposures of the denuded Cenozoic detachment fault system in the southern Sacramento Mountains (SE California) delimit the architecture of a regional low-angle normal fault, and highlight the evolution of these enigmatic faults. The fault was initiated ~23 Ma in quartzo-feldspathic basement gneiss and granitoids at a low-angle (2km, and amplitudes up to 100m. These corrugations are continuous along their hinges for up to 3.6 km. Damage zone fracture intensity varies both laterally, and perpendicular to the fault plane (over an area of 25km2), decreasing with depth in the footwall, and varies as a function of lithology and proximity to corrugation walls. Deformation is concentrated into narrow damage zones (100m) are found in areas where low-fracture intensity horses are corralled by sub-horizontal zones of cataclasite (up to 8m) and thick zones of epidote (up to 20cm) and silica-rich alteration (up to 1m). Sub-vertical shear and extension fractures, and sub-horizontal shear fractures/zones dominate the NE side of the core complex. In all cases, sub-vertical fractures verge into or are truncated by low-angle fractures that dominate the top of the damage zone. These low-angle fractures have an antithetic dip to the detachment fault plane. Some sub-vertical fractures become curviplanar close to the fault, where they are folded into parallelism with the sub-horizontal fault surface in the direction of transport. These field data, corroborated by ongoing microstructural analyses, indicate fault activity at a low angle accommodated by a variety of deformation mechanisms dependent on lithology, timing, fluid flow, and fault morphology.

  5. 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.

  6. Estimating background denudation rates and delivery of landslide sediment from a time series of 10Be concentrations in landslide dominated basins in the southern Central Range of Taiwan

    Science.gov (United States)

    Chen, C. Y.; Willett, S.; West, A. J.; Dadson, S. J.; Hovius, N.; Christl, M.; Shyu, J. B. H.

    2017-12-01

    The southern Central Range of Taiwan is located at a tectonic transition zone between an oceanic subduction zone and the arc-continent collision forming the Taiwan orogen. The rapidly evolving tectonic setting, tropical climate and frequent typhoons result in a complex uplift pattern, transient landscapes and extensive landslides. For this study, we obtained a series of 10Be concentrations over the last decade for 13 major drainage basins in the southern Central Range, bracketing the occurrence of a major typhoon, Morakot, which hit Taiwan in 2009 and triggered thousands of landslides. This time series allows us to simultaneously estimate the background erosion rate and assess the impact of Morakot-triggered landslides on 10Be concentrations. The time series of 10Be concentrations shows temporally lower concentrations of 10Be indicating dilution following the Morakot event in most basins. The diluted 10Be concentrations imply erosion rates up to three times higher than the lowest measured rates in the same basins. We constructed a simple sediment-mixing model parameterized by a sudden input of sediment supplied from landslides superimposed on a background denudation rate. This model was calibrated to measured landslide inventories and the series of 10Be data. We obtain a range of permissible background erosion rate and fraction of landslide sediments over time for each basin. The inferred background erosion rate reveals a northward increasing trend, reflecting the initial stage of the mountain building and indicating tectonic forcing is the main driver of the landscape evolution in the southern Central Range. The temporal changes in fraction of landslide sediments show that the available landslide material generated by the Morakot event is decreasing over time with a timescale of several years.

  7. Jurassic onychites (arm hooks) from squid-like cephalopods from the Wessex Basin, southern England

    Science.gov (United States)

    Hart, Malcolm; Hughes, Zoe; Page, Kevin; Price, Gregory; Smart, Christopher

    2017-04-01

    of hook that are often arranged in pairs. Using the abundance of material available to us from the Wessex Basin, we are attempting to identify the host animals wherever this is possible. If this can be established then it may 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 outside known lagerstätte. A recently described specimen (Bristol Museum and Art Gallery, BRMSG Ce12385) of only the hooks associated with 4 arms can, therefore, be attributed to the Clarkeiteuthis lineage. Coming from the Lower Pliensbachian of the Dorset Coast this occurrence falls in the stratigraphical 'gap' between the known taxa of the Sinemurian (Clarkeiteuthis montefiore) and the Toarcian (Clarkeiteuthis conocauda). This specimen does, however, show paired hooks of different types, similar to another specimen in Manchester University Museum: this is not seen in C. conocauda and places the specimen in C. montefiore or a yet undescribed species of Clarkeiteuthis. Engeser, T.S. & Clarke, M.R. 1988. Cephalopod hooks, both recent and fossil. In: Clarke, M.R. & Trueman, E.R. (eds), Palaeontology and Neontology of Cephalopods, vol. 12,; Wilbur, K.M. (Ed.), The Mollusca, Academic press Inc., London, 133-151. Hart, M.B. & Hutchinson, D. in press. A newly described 'clarkeiteuthid' from the Lias Group of Dorset. Geoscience in South-West England. Hart, M.B., De Jonghe, A., Page, K.N., Price, G.D. & Smart, C.W. 2016. Exceptional accumulations of statoliths in association with the Christian Malford lagerstätte (Callovian, Jurassic) in Wiltshire, United Kingdom. Palaios, 31, 203-220. Kulicki, C. & Szaniawski, H. 1972. Cephalopod arm hooks from the Jurassic of Poland. Acta Palaeontologica Polonica, 17, 379-419. Wilby, P.R., Hudson, J.D., Clements, R.G. & Hollingworth, N.T.J. 2004. Taphonomy and origin of an accumulate of soft-bodied cephalopods in the Oxford Clay

  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. Controls on large landslide distribution and implications for the geomorphic evolution of the southern interior Columbia River basin

    Science.gov (United States)

    Safran, E.B.; Anderson, S.W.; Mills-Novoa, M.; House, P.K.; Ely, L.

    2011-01-01

    Large landslides (>0.1 km2) are important agents of geomorphic change. While most common in rugged mountain ranges, large landslides can also be widespread in relatively low-relief (several 100 m) terrain, where their distribution has been relatively little studied. A fuller understanding of the role of large landslides in landscape evolution requires addressing this gap, since the distribution of large landslides may affect broad regions through interactions with channel processes, and since the dominant controls on landslide distribution might be expected to vary with tectonic setting. We documented >400 landslides between 0.1 and ~40 km2 across ~140,000 km2 of eastern Oregon, in the semiarid, southern interior Columbia River basin. The mapped landslides cluster in a NW-SE-trending band that is 50-100 km wide. Landslides predominantly occur where even modest local relief (~100 m) exists near key contacts between weak sedimentary or volcaniclastic rock and coherent cap rock. Fault density exerts no control on landslide distribution, while ~10% of mapped landslides cluster within 3-10 km of mapped fold axes. Landslide occurrence is curtailed to the NE by thick packages of coherent basalt and to the SW by limited local relief. Our results suggest that future mass movements will localize in areas stratigraphically preconditioned for landsliding by a geologic history of fluviolacustrine and volcaniclastic sedimentation and episodic capping by coherent lava flows. In such areas, episodic landsliding may persist for hundreds of thousands of years or more, producing valley wall slopes of ~7??-13?? and impacting local channels with an evolving array of mass movement styles. ?? 2011 Geological Society of America.

  10. Hydrologic Evaluation of Integrated Multi-satellite Retrivals for GPM over Nanliu River Basin in Southern China

    Science.gov (United States)

    Zhenqing, L.; Sheng, C.; Chaoying, H.

    2017-12-01

    The core satellite of Global Precipitation Measurement (GPM) mission was launched on 27 February2014 with two core sensors dual-frequency precipitation radar (DPR) and microwave imager (GMI). The algorithm of Integrated Multi-satellitE Retrievals for the Global Precipitation Measurement (GPM) mission (IMERG) blends the advantages of currently most popular satellite-based quantitative precipitation estimates (QPE) algorithms, i.e. TRMM Multi-satellite Precipitation Analysis (TMPA), Climate Prediction Center morphing technique (CMORPH) ADDIN EN.CITE ADDIN EN.CITE.DATA , Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Cloud Classification System (PERSIANN-CCS).Therefore, IMERG is deemed to be the state-of-art precipitation product with high spatio-temporal resolution of 0.1°/30min. The real-time and post real-time IMERG products are now available online at https://stormpps.gsfc.nasa.gov/storm. Early studies about assessment of IMERG with gauge observations or analysis products show that the current version GPM Day-1 product IMERG demonstrates promising performance over China [1], Europe [2], and United States [3]. However, few studies are found to study the IMERG' potentials of hydrologic utility.In this study, the real-time and final run post real-time IMERG products are hydrologically evaluated with gauge analysis product as reference over Nanliu River basin (Fig.1) in Southern China since March 2014 to February 2017 with Xinanjiang model. Statistics metrics Relative Bias (RB), Root-Mean-Squared Error (RMSE), Correlation Coefficient (CC), Probability Of Detection (POD), False Alarm Ratio (FAR), Critical Success Index (CSI), and Nash-Sutcliffe (NSCE) index will be used to compare the stream flow simulated with IMERG to the observed stream flow. This timely hydrologic evaluation is expected to offer insights into IMERG' potentials in hydrologic utility and thus provide useful feedback to the IMERG algorithm developers and

  11. A high resolution magnetostratigraphic profile across the Permian-Triassic boundary in the Southern Sydney Basin, eastern Australia

    Science.gov (United States)

    Belica, M. E.; Tohver, E.; Nicoll, R.; Denyszyn, S. W.; Pisarevsky, S.; George, A. D.

    2016-12-01

    The Permian-Triassic boundary (PTB) is associated with the largest mass extinction in Phanerozoic geologic history. Despite several decades of intense study, there is ongoing debate regarding the exact timing of extinction and the global correlation of marine and terrestrial P-T sections. The terrestrial record is hampered by a lack of index fossils; however, magnetostratigraphy offers an opportunity for correlation because it relies on the global synchronicity of magnetic reversals. A magnetostratigraphic profile across the Permian-Triassic boundary has been obtained from a stratigraphically continuous terrestrial section in the Southern Sydney Basin of eastern Australia. The 60 m section is located within the Narrabeen Group, which consists of fluvial to lacustrine sandstones and mudstones. Paleomagnetic samples were collected at one meter intervals to determine a detailed reversal record. Samples were stepwise thermally demagnetized to isolate a primary remanence, and magnetic susceptibility was measured in the field at 30 cm intervals with values ranging from -0.047-2.50 (10-3 SI units). Three normal and three reverse magnetozones were detected after removal of a low temperature overprint, and the results show good agreement with the Global Magnetic Polarity Timescale as well as marine Permian-Triassic sections where the PTB is well constrained. Furthermore, a reverse polarity subchron has been identified within the normal magnetozone spanning the PTB similar to results published from the Netherlands and China. The magnetic stratigraphy suggests that the Narrabeen Group was deposited during the late Changhsingian to early Induan, and provides a revised placement of the PTB in the lower Wombarra Claystone. Integration of the magnetostratigraphy with existing isotopic datasets suggests that the terrestrial extinction in eastern Australia occurred 7.5 m below the PTB in the Changhsingian Coalcliff Sandstone. A tuff within a coal seam underlying the Coalcliff

  12. 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

  13. 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

  14. [Spatial variation of soil carbon and stable isotopes in the southern margin desert of Junggar Basin, China].

    Science.gov (United States)

    Wang, Na; Xu, Wen Qiang; Xu, Hua Jun; Feng, Yi Xing; Li, Chao Fan

    2017-07-18

    The southern margin desert of Junggar Basin in the central arid region of Asia was selec-ted as the study area. To gain insight into the distribution characteristic of stable carbon isotope and the relationship between the change of soil carbon and the distance to oasis of soil organic carbon (SOC) and soil inorganic carbon (SIC), three belt transects were set according to the distance between the desert and the oasis in edge, middle and hinterland of the desert respectively, and collected the soil profile samples with depth of 2 m. The results indicated that the SOC content reduced with the soil depth, and the variation with the distance to oasis was the edge> the middle> the hinterland. The δ 13 C value of SOC varied in the range of -21.92‰ to -17.41‰, and decreased with the depth; the range in the middle and hinterland was -25.20‰ to -19.30‰, and increased then declined with the depth. Therefore, we could infer that the C3 plants played a dominant role in the central of desert, and had experienced the succession from C3 plants to C4 plants. The average content of SIC was 38.98 g·kg -1 in the edge of desert, which was about 6.01 folds as large as the content in the hinterland. This indicated that a large number of SIC with 0-2 m depth were clustered in the edge of the desert. The δ 13 C value of SIC increased first then decreased with the soil depth, and enriched in the bottom layer, which was mainly affected by the original carbonate content and soil carbon dioxide.

  15. Abandoned mine drainage in the Swatara Creek Basin, southern anthracite coalfield, Pennsylvania, USA: 2. performance of treatment systems

    Science.gov (United States)

    Cravotta, Charles A.

    2010-01-01

    A variety of passive and semi-passive treatment systems were constructed by state and local agencies to neutralize acidic mine drainage (AMD) and reduce the transport of dissolved metals in the upper Swatara Creek Basin in the Southern Anthracite Coalfield in eastern Pennsylvania. To evaluate the effectiveness of selected treatment systems installed during 1995–2001, the US Geological Survey collected water-quality data at upstream and downstream locations relative to each system eight or more times annually for a minimum of 3 years at each site during 1996–2007. Performance was normalized among treatment types by dividing the acid load removed by the size of the treatment system. For the limestone sand, open limestone channel, oxic limestone drain, anoxic limestone drain (ALD), and limestone diversion well treatment systems, the size was indicated by the total mass of limestone; for the aerobic wetland systems, the size was indicated by the total surface area of ponds and wetlands. Additionally, the approximate cost per tonne of acid treated over an assumed service life of 20 years was computed. On the basis of these performance metrics, the limestone sand, ALD, oxic limestone drain, and limestone diversion wells had similar ranges of acid-removal efficiency and cost efficiency. However, the open limestone channel had lower removal efficiency and higher cost per ton of acid treated. The wetlands effectively attenuated metals transport but were relatively expensive considering metrics that evaluated acid removal and cost efficiency. Although the water-quality data indicated that all treatments reduced the acidity load from AMD, the ALD was most effective at producing near-neutral pH and attenuating acidity and dissolved metals. The diversion wells were effective at removing acidity and increasing pH of downstream water and exhibited unique potential to treat moderate to high flows associated with storm flow conditions.

  16. Geomorphology Characterization of Ica Basin and Its Influence on the Dynamic Response of Soils for Urban Seismic Hazards in Ica, Peru

    Directory of Open Access Journals (Sweden)

    Isabel Bernal

    2018-01-01

    Full Text Available We evaluated the influence of the geomorphology of Peru’s Ica Basin on the dynamic response of soils of the city of Ica. We applied five geophysical methods: spectral ratio (H/V, frequency-wavenumber (F-K, multichannel analysis of surface waves (MASW, multichannel analysis of microtremor (MAM, and Gravimetric Analysis. Our results indicate that the soils respond to two frequency ranges: F0 (0.4–0.8 Hz and F1 (1.0–3.0 Hz. The F-K, which considers circular arrays, shows two tendencies with a jump between 1.0 and 2.0 Hz. MASW and MAM contribute to frequencies greater than 2.0 Hz. The inversion curve indicates the presence of three layers of 4, 16, and 60 m with velocities of 180, 250, and 400 m/s. The Bouguer anomalies vary between −17.72 and −24.32 mGal and with the spectral analysis we identified two deposits, of 60 m and 150 m of thickness. Likewise, the relationship between the velocities of 400 and 900 m/s, with the frequency = 1.5 Hz, allows us to determine the thickness for the layers of 60 (slightly alluvial to moderately compact and 150 m (soil-rock interface. These results suggest that the morphology of the Ica Basin plays an important role in the dynamic behavior of the soils to low frequency.

  17. Comparison of peak discharges among sites with and without valley fills for the July 8-9, 2001 flood in the headwaters of Clear Fork, Coal River basin, mountaintop coal-mining region, southern West Virginia

    Science.gov (United States)

    Wiley, Jeffrey B.; Brogan, Freddie D.

    2003-01-01

    The effects of mountaintop-removal mining practices on the peak discharges of streams were investigated in six small drainage basins within a 7-square-mile area in southern West Virginia. Two of the small basins had reclaimed valley fills, one basin had reclaimed and unreclaimed valley fills, and three basins did not have valley fills. Indirect measurements of peak discharge for the flood of July 8-9, 2001, were made at six sites on streams draining the small basins. The sites without valley fills had peak discharges with 10- to 25-year recurrence intervals, indicating that rainfall intensities and totals varied among the study basins. The flood-recurrence intervals for the three basins with valley fills were determined as though the peak discharges were those from rural streams without the influence of valley fills, and ranged from less than 2 years to more than 100 years.

  18. Sedimentology and sequence stratigraphy from outcrops of the Kribi-Campo sub-basin: Lower Mundeck Formation (Lower Cretaceous, southern Cameroon)

    Science.gov (United States)

    Ntamak-Nida, Marie Joseph; Bourquin, Sylvie; Makong, Jean-Claude; Baudin, François; Mpesse, Jean Engelbert; Ngouem, Christophe Itjoko; Komguem, Paul Bertrand; Abolo, Guy Martin

    2010-08-01

    The Kribi-Campo sub-basin is composed of an Early to Mid Cretaceous series from West Africa's Atlantic coast and is located in southern Cameroon in the Central African equatorial rain forest. It is the smallest coastal basin in Cameroon and forms the southern part of the Douala/Kribi-Campo basin known as Douala basin ( s.l.). Until now, no detailed sedimentological studies have been carried out on the outcrops of this basin located in the Campo area. The aim of this study was to characterise the depositional environments, vertical evolution and tectonic context of these Lower Cretaceous series in order to make a comparison with adjacent basins and replace them in the geodynamic context. Facies analysis of the Lower Mundeck Formation (Lower Cretaceous) indicates the presence of four major, interfigered facies associations, that are inferred to represent elements of an alluvial to lacustrine-fan delta system. The clast lithologies suggest proximity of relief supplying coarse-grained sediment during the deposition of the Lower Mundeck Formation at Campo. The general dip and direction of the bedding is approximately 10°-12°NW, which also corresponds to the orientation of the foliations in the underlying metamorphic basement. The main sedimentary succession is characterised by a major retrogradational/progradational cycle of Late Aptian age, evaluated at about 3 Ma, with a well-developed progradational trend characterised by fluctuations of the recognised depositional environments. Fluctuations in lake level and sediment supply were possibly controlled by active faults at the basin margin, although climatic changes may have also played a role. The consistently W-WNW palaeoflow of sediments suggests that the palaeorelief was located to the east and could be oriented in a NNE-SSW direction, downthrown to the west. Local outcrops dated as Albian, both north and south of the main outcrop, display some marine influence. These deposits are cut by 040-060 faults parallel to

  19. Peru, People and Plants.

    Science.gov (United States)

    Thompson, Dennis

    Designed for horticulture, horticulture therapy, and botany students at Edmonds Community College (Washington), this 6-hour module explores the pre-Columbian use of plant materials in Peru and its relationships to cultural practices in modern Peru. The first sections provide basic information about the module, such as its objectives, the concepts…

  20. EnviSAT ASAR Monitoring Of The Natural And Archaeological Landscape Of Nasca, Peru

    Science.gov (United States)

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

    2013-12-01

    We exploit the 4year-long archive of ENVISAT ASAR IS2 C-band imagery available through ESA Cat-1 project id.11073 over Nasca (Southern Peru), to reconstruct the temporal evolution of the Rio Grande drainage basin and its impacts on the natural and cultural heritage preserved within this region, well- known for the evidences of the ancient Paracas and Nasca Civilizations who flourished between the 4th century BC and the 6th century AD. Inferences about the recent changes of the cultural landscapes and the main landforms in 2003-2007 were retrieved based on SAR backscattering (σ0) time series. Ancient aqueduct systems (the so-called puquios) and the famous geoglyphs ('Nasca Lines') were detected, even at a medium-resolution scale provided by ENVISAT images.

  1. The Quequén Salado river basin: Geology and biochronostratigraphy of the Mio-Pliocene boundary in the southern Pampean plain, Argentina

    Science.gov (United States)

    Beilinson, E.; Gasparini, G. M.; Tomassini, R. L.; Zárate, M. A.; Deschamps, C. M.; Barendregt, R. W.; Rabassa, J.

    2017-07-01

    The Quequén Salado river basin has been the focus of several contributions since the first decades of the XX century, namely dealing with the general geological features of the deposits and with the vertebrate remains. In this paper, the Neogene geological history documented by the Quequén Salado river exposures is reconstructed by means of stratigraphic, sedimentological and paleomagnetic studies along with the paleontological analysis of vertebrate remains. The study area is a crucial setting not only to better understand the evolution of the southern Pampas basin during the late Miocene-early Pliocene interval, but also to test the validity of the biochronologic and biostratigraphic schemes, especially the "Irenense". A geological model for the Quequén Salado river valley is proposed: a case of downcutting and headward erosion that contributes with a coherent interpretation to explain the spatial distribution of facies and fossil taxa: the younger in the distal sector of the Quequén Salado middle basin and the older in the lower basin. The sedimentary record is believed to represent the distal reaches of a distributary fluvial system that drained from the Ventania ranges. The stratigraphic section of Paso del Indio Rico results a key stratigraphic site to fully understand the stratigraphic nature of the boundary between the Miocene and the Pliocene (the Huayquerian and Montehermosan stages/ages). In this sense, two stratigraphically superposed range zones have been recognized in the area: Xenodontomys ellipticus Range Zone (latest Miocene-early Pliocene; late Huayquerian), and Eumysops laeviplicatus Range Zone (early Pliocene; Montehermosan). Taking into account the available geological and paleontological evidences, the "Irenense" would not represent a valid biostratigraphic unit, since, according to the geological model here proposed, it would be represented by elements of the Xenodontomys ellipticus Range Zone in the lower QS basin and by elements of the

  2. 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...... marginal basin, and the mechanics of and strain distribution during its subsequent closure. In order to investigate the deposition, the tectonic deformation and the fluid migration, geological mapping of a key area of the basin has been performed. In addition, georadar reflection profiles have been...... covered. This study highlighted several sulphide-rich horizon within the basal succession of the basin infill. The sulphides are either in relation with tectonic structures or with genuinely clay-rich deposits. The studied succession shows a progressive deepening of the basin through time with facies...

  3. Stratigraphy and paleogeographic significance of a Late Pennsylvanian to Early Permian channeled slope sequence in the Darwin Basin, southern Darwin Hills, east-central California

    Science.gov (United States)

    Stevens, Calvin H.; Stone, Paul; Magginetti, Robert T.; Ritter, Scott M.

    2015-01-01

    The complex stratigraphy of late Paleozoic rocks in the southern Darwin Hills consists of regionally extensive Mississippian and Early to Middle Pennsylvanian rocks overlain by latest Pennsylvanian to Early Permian rocks, herein called the Darwin Hills sequence. Deposition of this latter sequence marked the beginning of the Darwin Basin. In Mississippian time, a carbonate platform prograded westward over slightly older slope deposits. In the Late Mississippian this platform was exposed to erosion and siliciclastic sediments were deposited. In Early to Middle Pennsylvanian time the area subsided, forming a west-facing ramp that was subjected to deformation and erosion in Middle or early Late Pennsylvanian time. Later this area was tilted westward and deep-water sediments were deposited on this slope. In latest Pennsylvanian to earliest Permian time, a major channel was cut through the older Pennsylvanian rocks and into the Upper Mississippian strata. This channel was gradually filled with increasingly finer grained, deep-water sediment as the area evolved into a basin floor by Early Permian (Sakmarian) time. Expansion of the Darwin Basin in Artinskian time led to a second phase of deposition represented by strata of the regionally extensive Darwin Canyon Formation. The geology in this small area thus documents tectonic events occurring during the early development of the Darwin Basin.

  4. Crust and upper-mantle structure of Wanganui Basin and southern Hikurangi margin, North Island, New Zealand as revealed by active source seismic data

    Science.gov (United States)

    Tozer, B.; Stern, T. A.; Lamb, S. L.; Henrys, S. A.

    2017-11-01

    Wide-angle reflection and refraction data recorded during the Seismic Array HiKurangi Experiment (SAHKE) are used to constrain the crustal P-wave velocity (Vp) structure along two profiles spanning the length and width of Wanganui Basin, located landwards of the southern Hikurangi subduction margin, New Zealand. These models provide high-resolution constraints on the structure and crustal thickness of the overlying Australian and subducted Pacific plates and plate interface geometry. Wide-angle reflections are modelled to show that the subducted oceanic Pacific plate crust is anomalously thick (∼10 km) below southern North Island and is overlain by a ∼1.5-4.0 km thick, low Vp (4.8-5.4 km s-1) layer, interpreted as a channel of sedimentary material, that persists landwards at least as far as Kapiti Island. Distinct near vertical reflections from onshore shots identify a ∼4 km high mound of low-velocity sedimentary material that appears to underplate the overlying Australian plate crust and is likely to contribute to local rock uplift along the Axial ranges. The overriding Australian plate Moho beneath Wanganui Basin is imaged as deepening southwards and reaches a depth of at least 36.4 km. The Moho shape approximately mirrors the thickening of the basin sediments, suggestive of crustal downwarping. However, the observed crustal thickness variation is insufficient to explain the large negative Bouguer gravity anomaly (-160 mGal) centred over the basin. Partial serpentinization within the upper mantle with a concomitant density decrease is one possible way of reconciling this anomaly.

  5. FOXO3 variants are beneficial for longevity in Southern Chinese living in the Red River Basin: A case-control study and meta-analysis

    OpenAIRE

    Sun, Liang; Hu, Caiyou; Zheng, Chenguang; Qian, Yu; Liang, Qinghua; Lv, Zeping; Huang, Zezhi; Qi, KeYan; Gong, Huan; Zhang, Zheng; Huang, Jin; Zhou, Qin; Yang, Ze

    2015-01-01

    Forkhead box class O (FOXO) transcription factors play a crucial role in longevity across species. Several polymorphisms in FOXO3 were previously reported to be associated with human longevity. However, only one Chinese replication study has been performed so far. To verify the role of FOXO3 in southern Chinese in the Red River Basin, a community-based case-control study was conducted, and seven polymorphisms were genotyped in 1336 participants, followed by a meta-analysis of eight case-contr...

  6. 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)

    Barriere, J.P.

    2003-01-01

    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.)

  7. Black Mats, Spring-Fed Streams, and Late-Glacial-Age Recharge in the Southern Great Basin

    Science.gov (United States)

    Quade, Jay; Forester, R.M.; Pratt, W.L.; Carter, C.

    1998-01-01

    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 tappaniana and Vertigo berryi are 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 okeechobi and 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 ??13C values of organic matter in the black mats range from -12 to -26???, reflecting contributions of tissue from both C3 (sedges, most shrubs and trees) and C4 (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 yrB.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

  8. Detailed chronology of a giant Pleistocene rock-avalanche sequence in the hyperarid southern Peru revealed by jointly applied 10Be and 3He cosmic ray exposure dating : The Study case of the Cerro Caquilluco landslide complex.

    Science.gov (United States)

    Swann, Zerathe; Laurence, Audin; Carlos, Benavente; Régis, Braucher; Pierre-Henri, Blard; Didier, Bourlès; Julien, Carcaillet; Fabrizio, Delgado; Pascal, Lacroix; Valderrama Patricio, Murillo; Aster Team

    2015-04-01

    Giant landslides are recognized to be remarkably abundant on the Western Andean front of southern Peru and northern Chile, especially in the Arica Bend region (e.g. Crosta et al., 2014a). This area is characterized by strong topographic gradients and subsequent incision of deep canyons, due to the evolution of the Andean range that provide suitable conditions for the development of such instabilities. The climate is hyper-arid (Atacama Desert), although rare but highly impulsive wet events have been evidenced since the Pleistocene. In parallel, this region is submitted to strong (Mw 8-9) and recurrent (~100 yrs) subduction earthquakes. Previous studies suggest that large landslides represent the main agent of erosion of the Western Cordillera, providing soft material for subsequent fluvial remobilization. However the lack of time constrains on the numerous fossil landslides identified away from major canyons still hamper to assess a real mass balance of sliding material versus the known fluvial erosion and tectonic uplift rates. Finally the role of landslides in the long-term erosion rates of the Andean range on its arid flank remains quantitatively unknown. Recently, two studies gave divergent opinions about the main factor supposed to control the slope failures in that region. Based on cosmogenic nuclides derived erosion rates, McPhillips et al. (2014) argue that the last Holocene climate variation did not have had any effect on the rate of landsliding, suggesting that here landslides are mainly triggered by earthquake. On the other hand, Margirier et al. (2014) have showed a temporal correlation between a failure episode of the giant Chuquibamba landslide and the Ouki wet climatic event identified on the Altiplano ~100 ka ago. In this study we focus on dating the Cerro Caquilluco rock avalanche complex described by Crosta et al. (2014). With a total volume of about 15 km3, a length of 43 km and an internal structure characterized by various depositional lobes

  9. 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.

  10. 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. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  11. Short report: serologic evidence of human ehrlichiosis in Peru.

    Science.gov (United States)

    Moro, Pedro L; Shah, Jyotsna; Li, Olga; Gilman, Robert H; Harris, Nick; Moro, Manuel H

    2009-02-01

    A serosurvey for human ehrlichiosis caused by Ehrlichia chaffeensis and Anaplasma phagocytophilum was performed in different regions of Peru by using indirect immunofluorescence assays (IFAs). Regions included an urban community in a shantytown in Lima (Pampas) and three rural communities located on the northern coast of Peru (Cura Mori), in the southern Peruvian Andes (Cochapata), and in the Peruvian jungle region (Santo Tomas). An overall E. chaffeensis seroprevalence of 13% (21 of 160) was found by IFA. Seroprevalences in females and males was 15% (16 of 106) and 9% (5 of 53), respectively. Seroprevalences in Cura Mori, Cochapata, Pampas, and Santo Tomas were 25% (10 of 40), 23% (9 of 40), 3% (1 of 40), and 3% (1 of 40), respectively. Seroprevalences in Cura Mori and Cochapata were significantly higher than in Santo Tomas or Pampas (P Peru. Further studies are needed to characterize Ehrlichia species in Peru, their vectors and their clinical significance.

  12. Dental education in Peru.

    Science.gov (United States)

    Komabayashi, Takashi; Sato, Manuel; Rodiguez, Lyly; Sato, Doris; Bird, William F

    2008-09-01

    This paper provides information about Peru's dental history and dental school system, including the curriculum and dental licensure. With the increase in the number of dental schools in Peru, the number of dentists is also increasing. Until 1965, Peru had only three dental schools; currently, there are 14. Four of these dental schools are public, and ten are private. A five- or six-year dental program leads to the B.D.S. degree. After successful completion of a thesis defense or competency examination, the D.D.S. degree is awarded. The D.D.S. is mandatory for practicing dentistry in Peru. Currently, there are approximately 14,000 active dentists, with a dentist-patient ratio of approximately 1:2,000.

  13. 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

  14. Contrasting isotopic mantle sources for proterozoic lamproites and kimberlites from the Cuddapah basin and eastern Dharwar craton: implication for proterozoic mantle heterogeneity beneath southern India

    International Nuclear Information System (INIS)

    Chalapathi Rao, N.V.; Gibson, S.A.; Pyle, D.M.; Dickin, A.P.

    1998-01-01

    Kimberlites intruding the Precambrian basement towards the western margin of the Cuddapah basin near Anantapur (1090 Ma) and Mahbubnagar (1360 Ma) in Andhra Pradesh have initial 87 Sr/ 86 Sr between 0.70205 to 0.70734 and σNd between +0.5 to +4.68. Mesoproterozoic lamproites (1380 Ma) from the Cuddapah basin (Chelima and Zangamarajupalle) and its NE margin (Ramannapeta) have initial 87 Sr/ 86 Sr between 0.70520 and 0.7390 and εNd from -6.43 to -8.29. Combined Sr- and Nd- isotopic ratios suggest that lamproites were derived from enriched sources which have time-averaged higher Rb/Sr and lower Sm/Nd ratios than the Bulk Earth whereas kimberlites were derived from depleted source with lower Rb/Sr and higher Sm/Nd ratios. Calculated T DM model ages suggest that the lamproite source enrichment (∼2 Ga) preceded that of kimberlites (∼1.37 Ga). Our work demonstrates the existence of isotopically contrasting upper mantle sources for southern Indian kimberlites and lamproites and provides evidence for a lateral, isotopically heterogeneous mantle beneath the Cuddapah basin and eastern Dharwar craton. The significance of our results in the context of diamond exploration is also highlighted. (author)

  15. U-Pb zircon constraints on the age of the Cretaceous Mata Amarilla Formation, Southern Patagonia, Argentina: Its relationship with the evolution of the Austral Basin

    International Nuclear Information System (INIS)

    Varela, Augusto N; Poire, Daniel G; Martin, Thomas; Gerdes, Axel; Goin, Francisco J; Gelfo, Javier N; Hoffmann, Simone

    2012-01-01

    Despite the abundant fossil content of the Mata Amarilla Formation (Southern Patagonia, Santa Cruz Province, Argentina), its age has always generated a considerable number of questions and debates. The chronological data provided by invertebrates, dinosaurs, fish, turtles, plesiosaurs and fossil flora are contradictory. In this work, twenty U-Pb spot analyses by laser ablation were carried out on the outer parts of the zoned zircon crystals from a tuff layer of the middle section of the Mata Amarilla Formation, yielding a U-Pb concordia age of 96.23±0.71 Ma, which corresponds to the middle Cenomanian. The deposition of the lower section of the Mata Amarilla Formation marks the onset of the foreland stage of the Austral Basin (also known as Magallanes Basin); this transition is characterized by the west-east shift of the depositional systems, which is consistent with the progradation of the Cretaceous fold-and-thrust belt. Thus, the onset of the foreland stage could have occurred between the upper Albian and lower Cenomanian, as the underlying Piedra Clavada Formation is lower Albian in age. On comparing the data obtained with information from the Ultima Esperanza Province in Chile, it can be suggested that the initiation of the closure of the Rocas Verdes Marginal Basin occurred simultaneously

  16. Terrorism in Peru.

    Science.gov (United States)

    Barrientos Hernandez, Dora H; Church, Adam L

    2003-01-01

    Two major domestic terrorist groups have plagued Peru over the past 20 years, the Sendero Luminoso or "Shining Path" (SL) and the Revolutionary Movement Túpac Amaru (MRTA). On 28 August 2003, the Peruvian Truth and Reconciliation Commission reported that an estimated 69,280 persons were killed in the internal conflict in Peru from 1980 to 2000. Most of the victims were farmers (56%), most attacks occurred in rural settings (79%), and the SL was responsible for most of the deaths (54%). Aggressive anti-terrorism efforts by police and military during this period, often at the expense of basic human rights, also contributed to this large burden of terrorism on Peru. During the 1990s, terrorist attacks in Peru had spread to its urban areas. On 17 December 1996, 22 members of MRTA took over the Japanese ambassador's residence in Lima, holding 72 hostages until the grounds were stormed by Peruvian special forces on 23 April 1997. Until recently, emergency planning and preparedness for terrorism-related events in Peru were largely underdeveloped. In the last five years, Peru has taken two key steps towards developing a mature emergency response system, with the establishment of the country's first emergency medicine residency training program and the construction of the first dedicated trauma center in Lima.

  17. Crustal structure of north Peru from analysis of teleseismic receiver functions

    Science.gov (United States)

    Condori, Cristobal; França, George S.; Tavera, Hernando J.; Albuquerque, Diogo F.; Bishop, Brandon T.; Beck, Susan L.

    2017-07-01

    In this study, we present results from teleseismic receiver functions, in order to investigate the crustal thickness and Vp/Vs ratio beneath northern Peru. A total number of 981 receiver functions were analyzed, from data recorded by 28 broadband seismic stations from the Peruvian permanent seismic network, the regional temporary SisNort network and one CTBTO station. The Moho depth and average crustal Vp/Vs ratio were determined at each station using the H-k stacking technique to identify the arrival times of primary P to S conversion and crustal reverberations (PpPms, PpSs + PsPms). The results show that the Moho depth correlates well with the surface topography and varies significantly from west to east, showing a shallow depth of around 25 km near the coast, a maximum depth of 55-60 km beneath the Andean Cordillera, and a depth of 35-40 km further to the east in the Amazonian Basin. The bulk crustal Vp/Vs ratio ranges between 1.60 and 1.88 with the mean of 1.75. Higher values between 1.75 and 1.88 are found beneath the Eastern and Western Cordilleras, consistent with a mafic composition in the lower crust. In contrast values vary from 1.60 to 1.75 in the extreme flanks of the Eastern and Western Cordillera indicating a felsic composition. We find a positive relationship between crustal thickness, Vp/Vs ratio, the Bouguer anomaly, and topography. These results are consistent with previous studies in other parts of Peru (central and southern regions) and provide the first crustal thickness estimates for the high cordillera in northern Peru.

  18. Tropical systems from the southwest Indian Ocean making landfall over the Limpopo River Basin, southern Africa: a historical perspective

    CSIR Research Space (South Africa)

    Malherbe, J

    2011-03-01

    Full Text Available The study provides perspective on the contribution of landfalling tropical systems (cyclones, depressions, storms and lows) from the southwest Indian Ocean (SWIO) towards rainfall over the eastern interior of southern Africa, over the period 1948...

  19. Pb/Pb isochron ages and Pb isotope geochemistry of Bambui Group carbonate rocks from the southern portion of the Sao Francisco Basin

    International Nuclear Information System (INIS)

    Babinski, M.

    1993-01-01

    This study involves the establishment of chemical and analytical procedure for Pb/Pb dating of Neo proterozoic carbonate rocks and their application to obtaining isochron ages of Bambui Group rocks from the southern portion of the Sao Francisco Basin, Minas Gerais State. The Pb isotopic compositions and U and Pb concentrations determined on more than 90 samples (≅ 600 analyses) from Sete Lagoas do Jacare formations, Bambui Group, from different parts of the basin, showed four distinct types of Pb, here called types I, II, III and IV. Type I Pb was found in samples with low Pb concentrations and relatively high U concentrations. Type II Pb is present in samples with relatively high Pb concentrations and low U concentrations it is non-radiogenic crustal Pb. Type III Pb is also found in samples with high Pb concentrations and low U concentrations but it is radiogenic crustal Pb. Type IV Pb occurs in samples with U/Pb ratios lower than 1 and is intermediate in composition between Type III and Type I Pb. According to the data presented in this paper it is suggested that carbonate rocks from Sete Lagoas Formations were deposited before 686±69 Ma. Rocks from the Lagoa do Jacare Formation, contained only Type II Pb, which does not permit determination of a Pb/Pb age. During the interval from 690 to 500 Ma, the Pb isotope system of the carbonate rocks from the Sao Francisco Basin was disturbed, and in some areas it was totally reset. The imprecise U/Pb ages of 550-600 Ma obtained from some of the carbonate rocks reflect this disturbance. The ages determined in this study are in agreement with most of the published ages of the tectonism from the Brasiliano fold belts marginal to Sao Francisco Craton, showing that the isotopic systems of Sao Francisco Basin rocks were largely affected by brasiliano tectonism. (author)

  20. Structuring of The Jurassic Basin of Chott in Gabes region (Southern Tunisia) associated to the Liassic rifting from geophysical and well data

    Science.gov (United States)

    Hassine, Mouna; Abbes, Chedly; Azaiez, Hajer; Gabtni, Hakim; Bouzid, Wajih

    2016-04-01

    The graben system of El Hamma, west of Gabes in Tunisia, corresponds to a pull apart basin developed in an extensive relay zone between two principal shear corridors (PSC) with a dextral sliding of N110-120 average direction. These PSC corresponds to two segments of the south-Atlasic shear corridor of NW-SE direction, which extends from Chott El Hodna in Algeria, to the NW, to the Libyan Djeferra to the SE (M.Hassine and al., 2015; M.Hassine and al., work in progress). This work aims to define the basin structuring during the Jurassic, especially from the Upper Lias during the Liassic rifting. For this, we performed seismic, gravity and well data analysis. Several wells situated in this basin and on its edges, which totally or partly crossed the Jurassic series which were described by several authors (J. Bonnefous, 1972 ; M. Soussi, 2002, 2004). These series corresponds to the Nara formation (PF Burollet, 1956) elevated to a group rank by M. Soussi (2003). It consists of two carbonate units separated by a marl-carbonate and sandstone member, dated successively of lower Lias (Hettangian- lower Pliensbachian.), Toarcian to Callovian and Upper Callovian-Tithonian. The correlation of this Jurassic formations along a North-South transect shows, from the South to the North, a significant variation in facies and thickness of the Jurassic series especially from the Upper Lias. Two resistant moles appears to the Northern and Southern edges of the pull-apart basin of El Hamma. The trend reversal of the lateral evolution of this series take place on the border NW-SE faults of the basin (PSC). The analysis of several seismic lines calibrated to well data, reveals a differentiated structuring inside the pull-apart basin itself, associated on the one hand, to the play of the N160 and N130-140 direction fault network which structure the basin in horsts and grabens of second order ( M. Hassine and al., 2015); and on the other hand, to the rise of the upper Triassic evaporates

  1. 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.

  2. The flux and recovery of bioactive substances in the surface sediments of deep basins off southern California

    International Nuclear Information System (INIS)

    Jahnke, R.A.

    1990-01-01

    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 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 3 H-adenine incorporation was compared with TCO 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

  3. 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…

  4. 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

  5. Petroleum investment conditions in Peru

    International Nuclear Information System (INIS)

    Garcia Schreck, M.

    1996-01-01

    This report focuses on the current petroleum investment conditions in Peru, and Peru's hydrocarbon potential. Investment conditions are examined, and political risk, internal security, the economic environment, and the legal framework for investment are considered. (UK)

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

    NARCIS (Netherlands)

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

    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

  7. Seasonal Distribution, Biology, and Human Attraction Patterns of Culicine Mosquitoes (Diptera: Culicidae) in a Forest Near Puerto Almendras, Iquitoes, Peru

    National Research Council Canada - National Science Library

    Jones, James

    2004-01-01

    This study was conducted, as part of a field-ecology study of arboviral activity in the Amazon Basin of Peru, to determine the taxonomy, frequency, seasonal, and vertical distributions of potential mosquito vectors...

  8. Impact of farm dams on river flows; A case study in the Limpopo River basin, Southern Africa

    NARCIS (Netherlands)

    Meijer, E.; Querner, E.P.; Boesveld, H.

    2013-01-01

    The study analysed the impact of a farm dam on the river flow in the Limpopo River basin. Two methods are used to calculate the water inflow: one uses the runoff component from the catchment water balance; the other uses the drainage output of the SIMFLOW model. The impact on the flow in a

  9. Hydrothermal alteration maps of the central and southern Basin and Range province of the United States compiled from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data

    Science.gov (United States)

    Mars, John L.

    2013-01-01

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and Interactive Data Language (IDL) logical operator algorithms were used to map hydrothermally altered rocks in the central and southern parts of the Basin and Range province of the United States. The hydrothermally altered rocks mapped in this study include (1) hydrothermal silica-rich rocks (hydrous quartz, chalcedony, opal, and amorphous silica), (2) propylitic rocks (calcite-dolomite and epidote-chlorite mapped as separate mineral groups), (3) argillic rocks (alunite-pyrophyllite-kaolinite), and (4) phyllic rocks (sericite-muscovite). A series of hydrothermal alteration maps, which identify the potential locations of hydrothermal silica-rich, propylitic, argillic, and phyllic rocks on Landsat Thematic Mapper (TM) band 7 orthorectified images, and geographic information systems shape files of hydrothermal alteration units are provided in this study.

  10. Study of fault configuration related mysteries through multi seismic attribute analysis technique in Zamzama gas field area, southern Indus Basin, Pakistan

    Directory of Open Access Journals (Sweden)

    Shabeer Ahmed Abbasi

    2016-03-01

    Full Text Available Seismic attribute analysis approach has been applied for the interpretation and identification of fault geometry of Zamzama Gas Field. Zamzama gas field area, which lies in the vicinity of Kirthar fold and thrust belt, Southern Indus Basin of Pakistan. The Zamzama fault and its related structure have been predicted by applying the Average Energy Attribute, Instantaneous Frequency Attribute, relative Acoustic Impedance Attribute and Chaotic Reflection Attribute on the seismic line GHPK98A.34. The results have been confirmed by applying the spectral decomposition attribute on the same seismic line that reveal the geometric configuration of Zamzama structure. The fault is reverse and started from 0 s and ended at the depth of 2.5 s on the vertical seismic section. Hanging wall moves up along the fault plane under the action of eastward oriented stress, which formed a large north–south oriented and eastward verging thrusted anticline.

  11. 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

  12. FOXO3 variants are beneficial for longevity in Southern Chinese living in the Red River Basin: A case-control study and meta-analysis.

    Science.gov (United States)

    Sun, Liang; Hu, Caiyou; Zheng, Chenguang; Qian, Yu; Liang, Qinghua; Lv, Zeping; Huang, Zezhi; Qi, KeYan; Gong, Huan; Zhang, Zheng; Huang, Jin; Zhou, Qin; Yang, Ze

    2015-04-27

    Forkhead box class O (FOXO) transcription factors play a crucial role in longevity across species. Several polymorphisms in FOXO3 were previously reported to be associated with human longevity. However, only one Chinese replication study has been performed so far. To verify the role of FOXO3 in southern Chinese in the Red River Basin, a community-based case-control study was conducted, and seven polymorphisms were genotyped in 1336 participants, followed by a meta-analysis of eight case-control studies that included 5327 longevity cases and 4608 controls. In our case-control study, we found rs2802288*A and rs2802292*G were beneficial to longevity after Bonferroni correction (pallele = 0.005, OR = 1.266; pallele = 0.026, OR = 1.207). In addition, in the longevity group, carriers with rs2802288*A and rs2802292*G presented reduced HbA1c (p = 0.001), and homozygotes of rs2802292*GG presented improved HOMA-IR (p = 0.014). The meta-analysis further revealed the overall contribution of rs2802288*A and rs2802292*G to longevity. However, our stratified analysis revealed that rs2802292*G might act more strongly in Asians than Europeans, for enhancement of longevity. In conclusion, our study provides convincing evidence for a significant association between the rs2802288*A and rs2802292*G gene variants in FOXO3 and human longevity, and adds the Southern Chinese in the Red River Basin to the growing number of human replication populations.

  13. 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.

  14. Mycobacterium ulcerans disease, Peru.

    Science.gov (United States)

    Guerra, Humberto; Palomino, Juan Carlos; Falconí, Eduardo; Bravo, Francisco; Donaires, Ninoska; Van Marck, Eric; Portaels, Françoise

    2008-03-01

    Eight adult patients (ages 18-58, 5 women) with Buruli ulcer (BU) confirmed by at least 2 diagnostic methods were seen in a 10-year period. Attempts to culture Mycobacterium ulcerans failed. Five patients came from jungle areas, and 3 from the swampy northern coast of Peru. The patients had 1-5 lesions, most of which were on the lower extremities. One patient had 5 clustered gluteal lesions; another patient had 2 lesions on a finger. Three patients were lost to follow-up. All 5 remaining patients had moderate disease. Diverse treatments (antituberculous drugs, World Health Organization [WHO] recommended antimicrobial drug treatment for BU, and for 3 patients, excision surgery) were successful. Only 1 patient (patient 7) received the specific drug treatment recommended by WHO. BU is endemic in Peru, although apparently infrequent. Education of populations and training of health workers are first needed to evaluate and understand the full extent of BU in Peru.

  15. Nuclear technology in Peru

    International Nuclear Information System (INIS)

    Montoya, M.

    1993-01-01

    This book deals with the Nuclear Energy in Peru. It consists of ten chapters. In the first chapter is presented a rapid overview on nuclear science history. The second chapter describes the nuclear proliferation and the nuclear competition in South America. The nuclear organization in Peru, the Peruvian Institute of Nuclear Energy, and the main centers are described in the third chapter. The following chapters deals with peruvian advances in nuclear medicine, agriculture and food, nuclear application to industry, hydrology, earth sciences and environmental considerations. In the last chapter, the perspectives for nuclear science and technology in Peru are described from the inter institutional cooperation point of view. This book also includes appendix and bibliography. (author)

  16. Potential field studies of the central San Luis Basin and San Juan Mountains, Colorado and New Mexico, and southern and western Afghanistan

    Science.gov (United States)

    Drenth, Benjamin John

    This dissertation includes three separate chapters, each demonstrating the interpretive utility of potential field (gravity and magnetic) geophysical datasets at various scales and in various geologic environments. The locations of these studies are the central San Luis Basin of Colorado and New Mexico, the San Juan Mountains of southwestern Colorado, and southern and western Afghanistan. The San Luis Basin is the northernmost of the major basins that make up the Rio Grande rift, and interpretation of gravity and aeromagnetic data reveals patterns of rifting, rift-sediment thicknesses, distribution of pre-rift volcanic and sedimentary rocks, and distribution of syn-rift volcanic rocks. Syn-rift Santa Fe Group sediments have a maximum thickness of ˜2 km in the Sanchez graben near the eastern margin of the basin along the central Sangre de Cristo fault zone. Under the Costilla Plains, thickness of these sediments is estimated to reach ˜1.3 km. The Santa Fe Group sediments also reach a thickness of nearly 1 km within the Monte Vista graben near the western basin margin along the San Juan Mountains. A narrow, north-south-trending structural high beneath San Pedro Mesa separates the graben from the structural depression beneath the Costilla Plains. Aeromagnetic anomalies are interpreted to mainly reflect variations of remanent magnetic polarity and burial depth of the 5.3-3.7 Ma Servilleta basalt of the Taos Plateau volcanic field. Magnetic-source depth estimates indicate patterns of subsidence following eruption of the basalt and show that the Sanchez graben has been the site of maximum subsidence. One of the largest and most pronounced gravity lows in North America lies over the rugged San Juan Mountains in southwestern Colorado. A buried, low-density silicic batholith related to an Oligocene volcanic field coincident with the San Juan Mountains has been the accepted interpretation of the source of the gravity low since the 1970s. However, this interpretation was

  17. Bentonites of the Irati Formation in the southern sector of the Parana Basin, Brazil; Bentonitas da Formacao Irati no setor sul da Bacia do Parana

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Aurelio Fagundes; Dani, Norberto; Remus, Marcus Vinicius Dornelles; Sommer, Margot Guerra, E-mail: norberto.dani@ufrgs.br, E-mail: marcus.remus@ufrgs.br, E-mail: margot.sommer@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil); Horn, Bruno Ludovico Dihl, E-mail: brunoldhorn@gmail.com [Servico Geologico do Brasil (CPRM), Recife, PE (Brazil). Superintendencia Regional

    2017-01-15

    This paper aims to identify and to present mineralogical and chemical arguments that demonstrate the existence of bentonite levels in the Irati Formation, found in outcrops to the west Acegua in southern Rio Grande do Sul (Brazil). These levels are thin, on average 4 cm thick, large in area, and are composed of grayish-white to greenish massive clay stones that contrast, in the field, with the shales of the Irati Formation. The bentonite levels of the Irati Formation are predominantly composed of Ca-montmorillonite, which constitutes the fine matrix of the rock; and scattered primary or magmatic crystals not larger than very fine sand. Among the main primary minerals representative of volcanic setting, it is possible to identify β-quartz paramorphs, sanidine, biotite, zircon, apatite and ilmenite, in addition to quartz and feldspar shards (splinters). More rarely, fragments of meso and macrocharcoals are found within the bentonite layers, which contrast with the maturity and type of non-vegetal organic matter of the Irati shale. Therefore, the nature of the precursor volcanism is inferred on the basis of rock geochemistry and crystal chemistry of the neoformed montmorillonite in the bentonite levels. Both methodologies indicate that during this period the volcanic ashes that reached the Parana Basin were generated by volcanism of intermediate composition, which is in accordance with what is known about the Lower Choiyoi Volcanic Province manifestations, which were synchronous with the sedimentation of the Irati Formation in the Parana Basin. (author)

  18. 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.

  19. Efficacy of sulfadoxine-pyrimethamine and mefloquine for the treatment of uncomplicated Plasmodium falciparum malaria in the Amazon basin of Peru Eficácia da sulfadoxina-pirimetamina e mefloquina no tratamento de malária não-complicada por Plasmodium falciparum na bacia amazônica peruana

    Directory of Open Access Journals (Sweden)

    Alan J. Magill

    2004-06-01

    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.Testes in vivo foram realizados para avaliar resistência a drogas antimalária, em pessoas com malária não complicada, causada por Plasmodium falciparum, numa região isolada da Bacia Amazônica, na fronteira com o Brasil e a Colômbia. Os testes mostraram resistência >50% RII/RIII a sulfadoxina-pirimetamina, mas não evidenciaram resistência a mefloquina.

  20. Cenomanian and Cenomanian-Turonian boundary deposits in the southern part of the Bohemian Cretaceous Basin, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Čech, S.; Hradecká, L.; Svobodová, Marcela; Švábenická, L.

    2005-01-01

    Roč. 80, č. 4 (2005), s. 321-354 ISSN 1210-3527 Grant - others:GA MŽP1(CZ) 1975/630/02 Institutional research plan: CEZ:AV0Z3013912 Keywords : Cenomanian * biostratigraphy * Bohemian Cretaceous Basin Subject RIV: DB - Geology ; Mineralogy http://www.geology.cz/bulletin/contents/2005/vol80no4/321_cech.pdf

  1. Identification of hydrogeochemical processes and pollution sources of groundwater nitrate in Leiming Basin of Hainan island, Southern China

    Science.gov (United States)

    Shaowen, Y.; Zhan, Y., , Dr; Li, Q.

    2017-12-01

    Identifying the evolution of groundwater quality is important for the control and management of groundwater resources. The main aims of the present study are to identify the major factors affecting hydrogeochemistry of groundwater resources and to evaluate the potential sources of groundwater nitrate in Leiming basin using chemical and isotopic methods. The majority of samples belong to Na-Cl water type and are followed by Ca-HCO3 and mixed Ca-Na-HCO3. The δ18O and δ2H values in groundwater indicate that the shallow fissure groundwater is mainly recharged by rainfall. The evaporated surface water is another significant origin of groundwater. The weathering and dissolution of different rocks and minerals, input of precipitation, evaporation, ion exchange and anthropogenic activities, especially agricultural activities, influence the hydrogeochemistry of the study area. NO- 3 concentration in the groundwater varies from 0.7 to 51.7 mg/L and high values are mainly occurred in the densely populated area. The combined use of isotopic values and hydrochemical data suggests that the NO- 3 load in Leiming basin is not only derived from agricultural activities but also from other sources such as waste water and atmospheric deposition. Fertilizer is considered as the major source of NO- 3 in the groundwater in Leiming basin.

  2. 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. Copyright © 2016. Published by Elsevier B.V.

  3. 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

  4. 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…

  5. IDRC in Peru

    International Development Research Centre (IDRC) Digital Library (Canada)

    financial services for the poor. For more information visit the. Regional Office for Latin America and the Caribbean (LAC) website: www.idrc.ca/lacro. Subscribe to the IDRC Bulletin and our regional bulletin: www.idrc.ca/idrcbulletin. PERU. ○. BRAZIL. COLOMBIA. ECUADOR. BOLIVIA. Pacific Ocean. 150 km. Lima. Callao.

  6. English Teaching Profile: Peru.

    Science.gov (United States)

    British Council, London (England). English Language and Literature Div.

    The role and status of English in Peru are examined, with attention directed to: (1) English within the education system; (2) teachers of English; (3) educational administration of English teaching, (4) materials support, development, and planning, (5) English outside the education system; (6) British and American support for the teaching of…

  7. 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

  8. IDRC in Peru

    International Development Research Centre (IDRC) Digital Library (Canada)

    Funding: $3,412,926. Donor: Canadian International Food Secu- rity Research Fund (IDRC and the Canadian. International Development Agency). Duration: 2011–2014. Grantees: Universidad Nacional Agraria La. Molina and Sociedad Peruana de Derecho. Ambiental, Peru and University of British. Columbia, Canada.

  9. 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 & ...

  10. Spotlight on Peru.

    Science.gov (United States)

    1997-01-01

    Lima's population grew from 1 million to 7 million during 1969-89, almost entirely due to rural-urban immigration. Other urban areas such as Iquitos experienced similar growth over the period. National, regional, and municipal governments have been working to restore civil order in the country and to bring basic health, sanitation, and education programs to the population. However, language, attitudinal, and cultural differences impede progress in this diverse and changing country. Peru's young population of median age 21 years presents a challenge to the development and implementation of effective reproductive health care programs for the country. Pathfinder's work in Peru is helped by current President Alberto Fujimori's strong and active support for family planning. In the face of strong opposition from the Roman Catholic Church, President Fujimori has held onto his conviction and commitment to reduce levels of maternal morbidity and mortality in Peru by increasing the accessibility of family planning programs. Pathfinder's work in Peru with the US Agency for International Development (USAID) includes the 5-year program Project 2000 designed to improve maternal and child health in 12 priority regions of the country. Pathfinder is also working with USAID to link family planning to postpartum services in 30 public hospitals throughout the country. New programs will be launched with contributions from individuals and foundations.

  11. Early migration and estuary stopover of introduced chinook salmon population in the Lapataia River Basin, southern Tierra del Fuego Island

    Science.gov (United States)

    Chalde, T.; Fernández, D. A.

    2017-12-01

    Established populations of chinook salmon (Oncorhynchus tshawytscha) have recently been reported in South America, at both Atlantic and Pacific basins. Several studies have evaluated different aspects of their life histories; however, little is known about the use of the estuaries by the juveniles of these populations. We examined spawning time, seaward migration timing, growth rate, scale patterns, diet, and geometric morphometric, contrasting the early life history during freshwater and estuary residence of a chinook population established in Lapataia Basin. Fall run spawning took place in March-April and the parr emerged in September. Two distinct seaward migration patterns were identified from sein net fishing records: one population segment migrating earlier to the estuary in October and a second group migrating later in February. The growth rate of fish captured at the estuary was significantly higher than the fish captured in freshwater. In addition, higher scale intercirculi distances were observed in estuary fish showing differences in growth rate. The feeding habitat in fish captured in both environments changed through time from bottom feeding to surface feeding and from significant diet overlap to no overlap. The morphology of the fish captured at the estuary was associated with the elongation of the caudal peduncle and a decrease in the condition factor index, both changes related to smolt transformation. The earlier migration and the higher growth rate of juveniles in the estuary together with fish of 1 + yo captured in this environment reveal that the estuary of Lapataia Basin is not only a stopover for the chinook salmon, but also a key habitat to reside and feed previous to the final seaward migration.

  12. The Mediterranean Basin and Southern Europe in a warmer world: what can we learn from the past?

    Directory of Open Access Journals (Sweden)

    Joel eGuiot

    2015-06-01

    Full Text Available Since the late-nineteenth century, surface temperatures have non-uniformly increased worldwide. The repercussion of the global warming in drylands, such as in the Mediterranean, may become a main source of concern in a near future, as it is often accompanied by increased droughts, that will severely degrade water supply and quality. History shows that access to water resources has always presented a challenge for societies around the Mediterranean throughout the Holocene (roughly the last 10,000 years. Repeatedly, adverse climate shifts seem to have interacted with social, economic and political variables, exacerbating vulnerabilities in drier regions. We present a reconstruction of the Holocene climate in the Mediterranean Basin using an innovative method based on pollen data and vegetation modeling. The method consists in calculating the inputs of the vegetation model so that the outputs fit the pollen data, using a Bayesian framework. This model inversion is particularly suited to deal with increasing dissimilarities between past millennia and the last century, especially due to a direct effect of CO2 on vegetation. The comparison of fardistant past and last century shows that the intensity of century-scale precipitation fall, amplified by higher temperatures and then evapotranspiration, appears to be unmatched over the last 10,000 years and the comparison between west and east precipitation anomalies show a clear see-saw effect through all the Holocene, in particular during the dry episodes of Near and Middle East. As a consequence that Tthe recent climatic change seems thento have been unprecedented during the last 10,000 years in the Mediterranean Basin,.over the next few decades, Mediterranean societies will likely be more critically vulnerable to climate change, than at any dry period of the past. We show also that adverse climate shifts are often correlated with the decline or collapse of Mediterranean civiliszations, particularly in

  13. Diabetes Mellitus in Peru.

    Science.gov (United States)

    Villena, Jaime E

    2015-01-01

    Peru is an upper medium-income developing country with an increasing prevalence of chronic diseases, including diabetes. To review and describe the epidemiology, drivers, and diabetes care plan in Peru. The medical literature was reviewed based on systematic searching of PubMed, Scielo, and various gray literature from the International Diabetes Federation, World Health Organization, and local Peruvian agencies. In Peru, diabetes affects 7% of the population. Type 2 diabetes accounts for 96.8% of outpatients visits with this condition. Type 1 diabetes has an incidence of 0.4/100,000 per year, and gestational diabetes affects 16% of pregnancies. The prevalence of glucose intolerance is 8.11% and that of impaired fasting glucose 22.4%. The prevalence of overweight, obesity, and metabolic syndrome in adults is 34.7%, 17.5%, and 25%, respectively. Metabolic syndrome prevalence is greater in women and the elderly and at urban and low-altitude locations. Diabetes is the eighth cause of death, the sixth cause of blindness, and the leading cause of end-stage kidney disease and nontraumatic lower limb amputation. In Peru, diabetes accounts for 31.5% of acute myocardial infarctions and 25% of strokes. Infections, diabetic emergencies, and cardiovascular disorders are the main causes for admissions, with a mortality rate Diabetes is a major health care issue in Peru that exposes difficult challenges and shortcomings. The national strategy for tackling diabetes includes promotion of healthy lifestyles; training primary care physicians and providing them with evidence-based clinical practice guidelines, safe and effective medications, and tools for monitoring treatment; and, finally, construction of a comprehensive health care network for early referral in order to prevent, detect, and treat diabetic complications. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  14. Fishes of the Taquari-Antas river basin (Patos Lagoon basin, southern Brazil Peixes da bacia do rio Taquari-Antas (sistema da Laguna dos Patos, sul do Brasil

    Directory of Open Access Journals (Sweden)

    FG. Becker

    2013-02-01

    Full Text Available The aquatic habitats of the Taquari-Antas river basin (in the Patos Lagoon basin, southern Brazil are under marked environmental transformation because of river damming for hydropower production. In order to provide an information baseline on the fish fauna of the Taquari-Antas basin, we provide a comprehensive survey of fish species based on primary and secondary data. We found 5,299 valid records of fish species in the basin, representing 119 species and 519 sampling sites. There are 13 non-native species, six of which are native to other Neotropical river basins. About 24% of the total native species are still lacking a taxonomic description at the species level. Three native long-distance migratory species were recorded (Leporinus obtusidens, Prochilodus lineatus, Salminus brasiliensis, as well as two potential mid-distance migrators (Parapimelodus nigribarbis and Pimelodus pintado. Although there is only one officially endangered species in the basin (S. brasiliensis, restricted range species (21.7% of total species should be considered in conservation efforts.Os ambientes aquáticos da Bacia do rio Taquari-Antas (Bacia da Laguna dos Patos, sul do Brasil vêm sofrendo considerável transformação, principalmente em razão da implantação de barragens para geração de energia elétrica. Com o objetivo de estabelecer um diagnóstico amplo da ictiofauna da Bacia do Taquari-Antas, realizou-se um inventário das espécies dessa bacia a partir de dados primários e secundários. Foram obtidos 5.299 registros válidos de espécies de peixe na bacia, representando 119 espécies e 519 localidades amostradas. Ocorrem, na bacia, 13 espécies não nativas, seis das quais são oriundas de outras bacias neotropicais. Cerca de 24% de todas as espécies carecem de descrição taxonômica no nível específico. Foram registradas três espécies nativas migradoras de longa distância (Leporinus obtusidens, Prochilodus lineatus e Salminus brasiliensis e

  15. Volcanogenic-hydrothermal iron-rich materials from the southern part of the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S; Gupta, S; Charan, S; Mills, O.P.

    . This may further be corroborated by the E–W elongation of some of the N–S-oriented seamounts, caused by the addition of magmatic materials and are thus indicative of more than one episode of volcanism. There are additional evidences which indicate volcanic...-brown material from the Japan Basin. Mar. Geol. 129, 331–336. Aumento, F., Mitchell, W.S., 1975. Magnetic spherules from the Mid-Atlantic Ridge. Geology 3, 407–410. Barrett, T.J., Friedrichsen, H., 1982. Elemental and isotopic composition of some metalliferous...

  16. 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

  17. 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.

  18. 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.

  19. Hydrogeological behaviour of the Fuente-de-Piedra playa lake and tectonic origin of its basin (Malaga, southern Spain)

    Science.gov (United States)

    Rodriguez-Rodriguez, Miguel; Martos-Rosillo, Sergio; Pedrera, Antonio

    2016-12-01

    Changes in the quantity of groundwater input due to water extraction for irrigation and urban supply has modified the water balance in the Fuente de Piedra playa lake. We have analysed the hydrogeology of the playa-lake system and developed a water-level model by means of a simple long-term water balance and piezometric analysis. In addition, a tectonic model is proposed to explain the endorheic basin development that led to the formation of the playa. Upright folds developed since the late Miocene and density-driven subsidence favoured the setting-up of and endorheic system located between the Atlantic and the Mediterranean basins in the Quaternary. The underlying low permeability rocks beneath the playa form a very stable aquitard with highly saline groundwater that prevents groundwater recharge of the lake into the aquitard. The hydrological modelling allowed us to simulate the evolution of the wáter level under a scenario of unaltered conditions during a 13-year period, showing that the percentage of days with dry conditions varies from 24.8% of the time under altered conditions to 14.9% as far as an unaltered scenario is concerned.

  20. The character and causes of flash flood occurrence changes in mountainous small basins of Southern California under projected climatic change

    Directory of Open Access Journals (Sweden)

    Theresa M. Modrick

    2015-03-01

    Full Text Available Study region: Small watersheds (O[25 km2] in the mountain regions of southern California comprise the study region. Study focus: This paper examines changes in flash flood occurrence in southern California resulting from projected climatic change. The methodology synthesizes elements of meteorological modeling, hydrology and geomorphology into an integrated modeling approach to define flash flood occurrence in a systematic and consistent way on a regional basis with high spatial and temporal resolution appropriate for flash flooding. A single climate model with three-dimensional atmospheric detail was used as input to drive simulations for historical and future periods. New hydrological insights for the region: Results indicate an increase in flash flood occurrence for the study region. For two distributed hydrologic models employed, the increase in flash flood occurrence frequency is on average between 30% and 40%. Regional flash flood occurrence is characterized by near saturation of the upper soil layer, and wider ranges in lower soil layer saturation and in precipitation. Overall, a decrease in the total number of precipitation events was found, although with increased precipitation intensity, increased event duration, and higher soil saturation conditions for the 21st century. This combination could signify more hazardous conditions, with fewer precipitation events but higher rainfall intensity and over soils with higher initial soil moisture saturation, leading to more frequent occurrence of flash floods. Keywords: Flash flooding, Climate change, Soil moisture, Precipitation, Distributed hydrologic modeling

  1. 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

  2. Can a primary remanence be retrieved from partially remagnetized Eocence volcanic rocks in the Nanmulin Basin (southern Tibet) to date the India-Asia collision?

    Science.gov (United States)

    Huang, Wentao; Dupont-Nivet, Guillaume; Lippert, Peter C.; van Hinsbergen, Douwe J. J.; Dekkers, Mark J.; Guo, Zhaojie; Waldrip, Ross; Li, Xiaochun; Zhang, Xiaoran; Liu, Dongdong; Kapp, Paul

    2015-01-01

    Paleomagnetic dating of the India-Asia collision hinges on determining the Paleogene latitude of the Lhasa terrane (southern Tibet). Reported latitudes range from 5°N to 30°N, however, leading to contrasting paleogeographic interpretations. Here we report new data from the Eocene Linzizong volcanic rocks in the Nanmulin Basin, which previously yielded data suggesting a low paleolatitude ( 10°N). New zircon U-Pb dates indicate an age of 52 Ma. Negative fold tests, however, demonstrate that the isolated characteristic remanent magnetizations, with notably varying inclinations, are not primary. Rock magnetic analyses, end-member modeling of isothermal remanent magnetization acquisition curves, and petrographic observations are consistent with variable degrees of posttilting remagnetization due to low-temperature alteration of primary magmatic titanomagnetite and the formation of secondary pigmentary hematite that unblock simultaneously. Previously reported paleomagnetic data from the Nanmulin Basin implying low paleolatitude should thus not be used to estimate the time and latitude of the India-Asia collision. We show that the paleomagnetic inclinations vary linearly with the contribution of secondary hematite to saturation isothermal remanent magnetization. We tentatively propose a new method to recover a primary remanence with inclination of 38.1° (35.7°, 40.5°) (95% significance) and a secondary remanence with inclination of 42.9° (41.5°,44.4°) (95% significance). The paleolatitude defined by the modeled primary remanence—21°N (19.8°N, 23.1°N)—is consistent with the regional compilation of published results from pristine volcanic rocks and sedimentary rocks of the upper Linzizong Group corrected for inclination shallowing. The start of the Tibetan Himalaya-Asia collision was situated at 20°N and took place by 50 Ma.

  3. Oligosarcus jacuiensis (Characiformes: Characidae, a new species from the Uruguay and Jacuí River basins, southern Brazil

    Directory of Open Access Journals (Sweden)

    Naércio Aquino Menezes

    Full Text Available The new species herein described, collected in the Jacuí and Uruguay River basins, Rio Grande do Sul, Brazil, can be distinguished from the already known species of the genus, but Oligosarcus jenynsii, O. perdido, O. acutirostris, O. solitarius and O. hepsetus, by the number of perforated lateral line scales. It shares with the first two species the absence of a premaxillary foramen, present in the last three species and differs from O. jenynsii by having a smaller orbital diameter and the tip of the pectoral fin failing to reach the pelvic-fin origin, and from O. perdido by the presence of more horizontal scale rows around the caudal peduncle.

  4. The depositional setting of the Late Quaternary sedimentary fill in southern Bannu basin, Northwest Himalayan fold and thrust belt, Pakistan.

    Science.gov (United States)

    Farid, Asam; Khalid, Perveiz; Jadoon, Khan Zaib; Jouini, Mohammed Soufiane

    2014-10-01

    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.

  5. 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.

  6. [Update on tegumentary leishmaniasis and carrion's disease vectors in Peru].

    Science.gov (United States)

    Zorrilla, Victor; Vásquez, Gissella; Espada, Liz; Ramírez, Pablo

    2017-01-01

    Among approximately 190 species of Lutzomyia in Peru, only a small number have been identified as vectors of tegumentary leishmaniasis in Western and inter-Andean valleys. These include L. peruensis, L. verrucarum, L. tejadai, L. ayacuchensis, and L. pescei. In the Amazon region, L. yuilli yuilli, L. chagasi, L. davisi, and L. auraensis are naturally infected, among the subgenera Leishmania and Viannia. L. auraensis is newly reported as a potential vector of leishmaniasis in neotropical regions. Among the primary and most widely distributed vectors of human bartonellosis or Carrión's disease, L. verrucarum and L. peruensis are predominant in the Andean regions of northern, central, and southern Peru. Other potential vectors of Carrion's disease are L. serrana in the Monzon Valley, Huamalies, and Huanuco; L. pescei in Apurímac and Cusco; and L. robusta and L. maranonensis in Jaén, San Ignacio, and Utcubamba provinces, and the high forests of Peru. Because of the high prevalence of leishmaniasis and bartonellosis outside of known endemic areas in Peru, it is necessary to update data and distribution maps of these disease vectors. This may improve both prevention and control measures. Existing information about sandfly vectors in Peru is also provided in this article.

  7. Corpus Planning for the Southern Peruvian Quechua Language.

    Science.gov (United States)

    Coronel-Molina, Serafin M.

    1997-01-01

    The discussion of corpus planning for the Southern Quechua language variety of Peru examines issues of graphization, standardization, modernization, and renovation of Quechua in the face of increasing domination by the Spanish language. The efforts of three major groups of linguists and other scholars working on language planning in Peru, and the…

  8. Giant Otters in Peru

    OpenAIRE

    Schenk C.; Staib E.

    1992-01-01

    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.

  9. Child nutrition: Peru

    International Nuclear Information System (INIS)

    2003-01-01

    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)

  10. Lamprophyres from the Harohalli dyke swarm in the Halaguru and Mysore areas, Southern India: Implications for backarc basin magmatism

    Science.gov (United States)

    Lanjewar, Shubhangi; Randive, Kirtikumar

    2018-05-01

    The Bangalore and Harohalli dyke swarms occur in the eastern part of the Dharwar craton. The older Bangalore dyke swarm is made up of dolerites, trending east-west, and the younger contains alkaline dykes that trend approximately north-south. The lamprophyres of the Harohalli dyke swarm occur in the Halaguru and Mysore industrial areas where they are exposed as fresh porphyritic - panidiomorphic dykes, containing crustal xenoliths, and showing chilled contacts with the country rock charnokites. They are chiefly composed of amphiboles which form well-developed phenocrysts. Clinopyroxenes are present in some of the dykes. Compositional zoning is observed in clinopyroxenes and amphiboles; their zoning patterns indicate that the magma experienced cryptic variations and that fractional crystallization was a dominant process in the evolution of the Harohalli Lamprophyres (HRL). The HRL are calc-alkaline with shoshonitic affinity and exhibit a K2O/Na2O ratio of ∼1. They show primitive (MORB-like) trace-element characters. LILE and LREE both show marginally enriched patterns; whereas HFSE and HREE show strongly depleted patterns. In the regional geologic sense, HRL dykes are characterised by two major influences; namely, (i) primary source region characteristics, which are geochemically more primitive, roughly falling within fields of primitive - MORB and enriched- MORB and (ii) the continental lithosphere. The data points for the HRL distinctly show their proximity to N-MORB and scatter towards the continental crust. Moreover, features like xenolith assimilation might influence the trace-element characteristics of the HRL dykes. Such magmas with mixed characters can be formed in a backarc basin environment. Geochemical proxies such as Ba/Nb vs Nb/Yb, Ba/Th vs Th/Nb, and the water content of magmas; which have been effectively used for discriminating backarc basin magmas worldwide, also indicate that the HRL magmas were generated in a backarc environment with inputs from

  11. 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

  12. Vegetation Response to Climate Change in the Southern Part of Qinghai-Tibet Plateau at Basinal Scale

    Science.gov (United States)

    Liu, X.; Liu, C.; Kang, Q.; Yin, B.

    2018-04-01

    Global climate change has significantly affected vegetation variation in the third-polar region of the world - the Qinghai-Tibet Plateau. As one of the most important indicators of vegetation variation (growth, coverage and tempo-spatial change), the Normalized Difference Vegetation Index (NDVI) is widely employed to study the response of vegetation to climate change. However, a long-term series analysis cannot be achieved because a single data source is constrained by time sequence. Therefore, a new framework was presented in this paper to extend the product series of monthly NDVI, taking as an example the Yarlung Zangbo River Basin, one of the most important river basins in the Qinghai-Tibet Plateau. NDVI products were acquired from two public sources: Global Inventory Modeling and Mapping Studies (GIMMS) Advanced Very High Resolution Radiometer (AVHRR) and Moderate-Resolution Imaging spectroradiometer (MODIS). After having been extended using the new framework, the new time series of NDVI covers a 384 months period (1982-2013), 84 months longer than previous time series of NDVI product, greatly facilitating NDVI related scientific research. In the new framework, the Gauss Filtering Method was employed to filter out noise in the NDVI product. Next, the standard method was introduced to enhance the comparability of the two data sources, and a pixel-based regression method was used to construct NDVI-extending models with one pixel after another. The extended series of NDVI fit well with original AVHRR-NDVI. With the extended time-series, temporal trends and spatial heterogeneity of NDVI in the study area were studied. Principal influencing factors on NDVI were further determined. The monthly NDVI is highly correlated with air temperature and precipitation in terms of climatic change wherein the spatially averaged NDVI slightly increases in the summer and has increased in temperature and decreased in precipitation in the 32 years period. The spatial heterogeneity of

  13. VEGETATION RESPONSE TO CLIMATE CHANGE IN THE SOUTHERN PART OF QINGHAI-TIBET PLATEAU AT BASINAL SCALE

    Directory of Open Access Journals (Sweden)

    X. Liu

    2018-04-01

    Full Text Available Global climate change has significantly affected vegetation variation in the third-polar region of the world – the Qinghai-Tibet Plateau. As one of the most important indicators of vegetation variation (growth, coverage and tempo-spatial change, the Normalized Difference Vegetation Index (NDVI is widely employed to study the response of vegetation to climate change. However, a long-term series analysis cannot be achieved because a single data source is constrained by time sequence. Therefore, a new framework was presented in this paper to extend the product series of monthly NDVI, taking as an example the Yarlung Zangbo River Basin, one of the most important river basins in the Qinghai-Tibet Plateau. NDVI products were acquired from two public sources: Global Inventory Modeling and Mapping Studies (GIMMS Advanced Very High Resolution Radiometer (AVHRR and Moderate-Resolution Imaging spectroradiometer (MODIS. After having been extended using the new framework, the new time series of NDVI covers a 384 months period (1982–2013, 84 months longer than previous time series of NDVI product, greatly facilitating NDVI related scientific research. In the new framework, the Gauss Filtering Method was employed to filter out noise in the NDVI product. Next, the standard method was introduced to enhance the comparability of the two data sources, and a pixel-based regression method was used to construct NDVI-extending models with one pixel after another. The extended series of NDVI fit well with original AVHRR-NDVI. With the extended time-series, temporal trends and spatial heterogeneity of NDVI in the study area were studied. Principal influencing factors on NDVI were further determined. The monthly NDVI is highly correlated with air temperature and precipitation in terms of climatic change wherein the spatially averaged NDVI slightly increases in the summer and has increased in temperature and decreased in precipitation in the 32 years period. The

  14. Stratigraphic record of Pliocene-Pleistocene basin evolution and deformation within the Southern San Andreas Fault Zone, Mecca Hills, California

    Science.gov (United States)

    McNabb, James C.; Dorsey, Rebecca J.; Housen, Bernard A.; Dimitroff, Cassidy W.; Messé, Graham T.

    2017-11-01

    A thick section of Pliocene-Pleistocene nonmarine sedimentary rocks exposed in the Mecca Hills, California, provides a record of fault-zone evolution along the Coachella Valley segment of the San Andreas fault (SAF). Geologic mapping, measured sections, detailed sedimentology, and paleomagnetic data document a 3-5 Myr history of deformation and sedimentation in this area. SW-side down offset on the Painted Canyon fault (PCF) starting 3.7 Ma resulted in deposition of the Mecca Conglomerate southwest of the fault. The lower member of the Palm Spring Formation accumulated across the PCF from 3.0 to 2.6 Ma during regional subsidence. SW-side up slip on the PCF and related transpressive deformation from 2.6 to 2.3 Ma created a time-transgressive angular unconformity between the lower and upper members of the Palm Spring Formation. The upper member accumulated in discrete fault-bounded depocenters until initiation of modern deformation, uplift, and basin inversion starting at 0.7 Ma. Some spatially restricted deposits can be attributed to the evolution of fault-zone geometric complexities. However, the deformation events at ca. 2.6 Ma and 0.7 Ma are recorded regionally along 80 km of the SAF through Coachella Valley, covering an area much larger than mapped fault-zone irregularities, and thus require regional explanations. We therefore conclude that late Cenozoic deformation and sedimentation along the SAF in Coachella Valley has been controlled by a combination of regional tectonic drivers and local deformation due to dextral slip through fault-zone complexities. We further propose a kinematic link between the 2.6-2.3 Ma angular unconformity and a previously documented but poorly dated reorganization of plate-boundary faults in the northern Gulf of California at 3.3-2.0 Ma. This analysis highlights the potential for high-precision chronologies in deformed terrestrial deposits to provide improved understanding of local- to regional-scale structural controls on basin

  15. Seismic Velocity Structure and Improved Seismic Image of the Southern Depression of the Tainan Basin from Pre-Stack Depth Migration

    Directory of Open Access Journals (Sweden)

    Qunshu Tang Chan Zheng

    2010-01-01

    Full Text Available In this paper, a velocity model of the Southern Depression of the Tainan Basin is obtained along with its migrated image from an iterative pre-stack depth migration approach. The Cenozoic strata are uniformly layered with velocities varying from ~1.8 to ~3.6 km s-1. However, the general velocity is slightly lower in the NW segment than the SE. Both fractures and burial depth might be the controls of their seismic velocities. There is an unconformable contact between the Cenozoic and underlying Mesozoic strata with an abrupt velocity jump from ~3.2 to ~4.3 km s-1. The Mesozoic strata are recognized with acoustically distinct reflection patterns (chaotic, deformed and discontinuous and complex internal structures (uplift, folds and faults. Their interval velocities range from ~4.3 to ~4.7 km s-1 within a depth from ~3.5 down to ~12.5 km, and the maximum depositional thickness reaches up to 6.5 km. Multiple tectonic events such as collision, subsidence and uplift might be responsible for the complexity of the Mesozoic strata.

  16. 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.

  17. Mantle wedge structure beneath the Yamato Basin, southern part of the Japan Sea, revealed by long-term seafloor seismic observations

    Science.gov (United States)

    Shinohara, M.; Nakahigashi, K.; Yamashita, Y.; Yamada, T.; Mochizuki, K.; Shiobara, H.

    2016-12-01

    The Japanese Islands are located at subduction zones where Philippine Sea (PHS) plate subducts from the southeast beneath the Eurasian plate and the Pacific plate descends from the east beneath the PHS and Eurasian plates and have a high density of seismic stations. Many seismic tomography studies using land seismic station data were conducted to reveal the seismic structure. These studies discussed the relationship between heterogeneous structures and the release of fluids from the subducting slab, magma generation and movement in the subduction zone. However, regional tomography using the land station data did not have a sufficient resolution to image a deep structure beneath the Japan Sea.To obtain the deep structure, observations of natural earthquakes within the Japan Sea are essential. Therefore, we started the repeating long-term seismic observations using ocean bottom seismometers(OBSs) in the Yamato Basin from 2013 to 2016. We apply travel-time tomography method to the regional earthquake and teleseismic arrival-data recorded by OBSs and land stations. In this presentation, we will report the P and S wave tomographic images down to a depth of 300 km beneath the southern part of the Japan Sea. This study was supported by "Integrated Research Project on Seismic and Tsunami Hazards around the Sea of Japan" conducted by the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan.

  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. Formation mechanisms and sequence response of authigenic grain-coating chlorite: evidence from the Upper Triassic Xujiahe Formation in the southern Sichuan Basin, China

    Directory of Open Access Journals (Sweden)

    Yu Yu

    2016-11-01

    Full Text Available Abstract Authigenic grain-coating chlorite is widely distributed in the clastic rocks of many sedimentary basins around the world. These iron minerals were mainly derived from flocculent precipitates formed when rivers flow into the ocean, especially in deltaic environments with high hydrodynamic conditions. At the same time, sandstone sequences with grain-coating chlorites also tend to have relatively high glauconite and pyrite content. EPMA composition analysis shows that glauconites with “high Al and low Fe” content indicate slightly to semi-saline marine environments with weak alkaline and weakly reducing conditions. By analyzing the chlorite-containing sandstone bodies of the southern Sichuan Xujiahe Formation, this study found that chlorite was mainly distributed in sedimentary microfacies, including underwater distributary channels, distributary channels, shallow lake sandstone dams, and mouth bars. Chlorite had a tendency to form in the upper parts of sandstone bodies with signs of increased base level, representing the influence of marine (lacustrine transgression. This is believed to be influenced by megamonsoons in the Middle and Upper Yangtze Region during the Late Triassic Epoch. During periods of abundant precipitation, river discharges increased and more Fe particulates flowed into the ocean (lake. In the meantime, increases or decreases in lake level were only affected by precipitation for short periods of time. The sedimentary environment shifted from weakly oxidizing to weak alkaline, weakly reducing conditions as sea level increased, and Fe-rich minerals as authigenic chlorite and glauconite began to form and deposit.

  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)

    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. Genetic divergence in populations of Lutzomyia ayacuchensis, a vector of Andean-type cutaneous leishmaniasis, in Ecuador and Peru.

    Science.gov (United States)

    Kato, Hirotomo; Cáceres, Abraham G; Gomez, Eduardo A; Mimori, Tatsuyuki; Uezato, Hiroshi; Hashiguchi, Yoshihisa

    2015-01-01

    Haplotype and gene network analyses were performed on mitochondrial cytochrome oxidase I and cytochrome b gene sequences of Lutzomyia (Lu.) ayacuchensis populations from Andean areas of Ecuador and southern Peru where the sand fly species transmit Leishmania (Leishmania) mexicana and Leishmania (Viannia) peruviana, respectively, and populations from the northern Peruvian Andes, for which transmission of Leishmania by Lu. ayacuchensis has not been reported. The haplotype analyses showed higher intrapopulation genetic divergence in northern Peruvian Andes populations and less divergence in the southern Peru and Ecuador populations, suggesting that a population bottleneck occurred in the latter populations, but not in former ones. Importantly, both haplotype and phylogenetic analyses showed that populations from Ecuador consisted of clearly distinct clusters from southern Peru, and the two populations were separated from those of northern Peru. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  2. Rainfall Variability, Wetland Persistence, and Water–Carbon Cycle Coupling in the Upper Zambezi River Basin in Southern Africa

    Directory of Open Access Journals (Sweden)

    Lauren E. L. Lowman

    2018-05-01

    Full Text Available The Upper Zambezi River Basin (UZRB delineates a complex region of topographic, soil and rainfall gradients between the Congo rainforest and the Kalahari Desert. Satellite imagery shows permanent wetlands in low-lying convergence zones where surface–groundwater interactions are vigorous. A dynamic wetland classification based on MODIS Nadir BRDF-Adjusted Reflectance is developed to capture the inter-annual and seasonal changes in areal extent due to groundwater redistribution and rainfall variability. Simulations of the coupled water–carbon cycles of seasonal wetlands show nearly double rates of carbon uptake as compared to dry areas, at increasingly lower water-use efficiencies as the dry season progresses. Thus, wetland extent and persistence into the dry season is key to the UZRB’s carbon sink and water budget. Whereas groundwater recharge governs the expansion of wetlands in the rainy season under large-scale forcing, wetland persistence in April–June (wet–dry transition months is tied to daily morning fog and clouds, and by afternoon land–atmosphere interactions (isolated convection. Rainfall suppression in July–September results from colder temperatures, weaker regional circulations, and reduced instability in the lower troposphere, shutting off moisture recycling in the dry season despite high evapotranspiration rates. The co-organization of precipitation and wetlands reflects land–atmosphere interactions that determine wetland seasonal persistence, and the coupled water and carbon cycles.

  3. Economic Evaluation of Hydrological Ecosystem Services in Mediterranean River Basins Applied to a Case Study in Southern Italy

    Directory of Open Access Journals (Sweden)

    Marcello Mastrorilli

    2018-02-01

    Full Text Available Land use affects eco-hydrological processes with consequences for floods and droughts. Changes in land use affect ecosystems and hydrological services. The objective of this study is the analysis of hydrological services through the quantification of water resources, pollutant loads, land retention capacity and soil erosion. On the basis of a quantitative evaluation, the economic values of the ecosystem services are estimated. By assigning an economic value to the natural resources and to the hydraulic system, the hydrological services can be computed at the scale of catchment ecosystem. The proposed methodology was applied to the basin “Bonis” (Calabria Region, Italy. The study analyses four land use scenarios: (i forest cover with good vegetative status (baseline scenario; (ii modification of the forest canopy; (iii variation in forest and cultivated surfaces; (iv insertion of impermeable areas. The simulations prove that the variations of the state of forest areas has considerable influence on the water balance, and then on the provided economic value. Small economic changes derive from reducing the impermeable areas. Increasing the agricultural area to 50% of the total, and reducing the forest surface, affects soil erosion, reduces the storage capacity of the water, and consequently the water harvesting. The suggested methodology can be considered a suitable tool for land planning.

  4. Lacustrine Environment Reservoir Properties on Sandstone Minerals and Hydrocarbon Content: A Case Study on Doba Basin, Southern Chad

    Science.gov (United States)

    Sumery, N. F. Mohd; Lo, S. Z.; Salim, A. M. A.

    2017-10-01

    The contribution of lacustrine environment as the hydrocarbon reservoir has been widely known. However, despite its growing importance, the lacustrine petroleum geology has received far less attention than marine due to its sedimentological complexity. This study therefore aims in developing an understanding of the unique aspects of lacustrine reservoirs which eventually impacts the future exploration decisions. Hydrocarbon production in Doba Basin, particularly the northern boundary, for instance, has not yet succeeded due to the unawareness of its depositional environment. The drilling results show that the problems were due to the: radioactive sand and waxy oil/formation damage, which all are related to the lacustrine depositional environment. Detailed study of geological and petrophysical integration on wireline logs and petrographic thin sections analysis of this environment helps in distinguishing reservoir and non-reservoir areas and determining the possible mechanism causing the failed DST results. The interpretations show that the correlation of all types> of logs and rho matrix analysis are capable in identifying sand and shale bed despite of the radioactive sand present. The failure of DST results were due to the presence of arkose in sand and waxy oil in reservoir bed. This had been confirmed by the petrographic thin section analysis where the arkose has mineral twinning effect indicate feldspar and waxy oil showing bright colour under fluorescent light. Understanding these special lacustrine environment characteristics and features will lead to a better interpretation of hydrocarbon prospectivity for future exploration.

  5. Status of groundwater quality in the Southern, Middle, and Northern Sacramento Valley study units, 2005-08: California GAMA Priority Basin Project

    Science.gov (United States)

    Bennett, George L.; Fram, Miranda S.; Belitz, Kenneth

    2011-01-01

    Groundwater quality in the Southern, Middle, and Northern Sacramento Valley study units was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study units are located in California's Central Valley and include parts of Butte, Colusa, Glenn, Placer, Sacramento, Shasta, Solano, Sutter, Tehama, Yolo, and Yuba 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 and the Lawrence Livermore National Laboratory. The three study units were designated to provide spatially-unbiased assessments of the quality of untreated groundwater in three parts of the Central Valley hydrogeologic province, as well as to provide a statistically consistent basis for comparing water quality regionally and statewide. Samples were collected in 2005 (Southern Sacramento Valley), 2006 (Middle Sacramento Valley), and 2007-08 (Northern Sacramento Valley). The GAMA studies in the Southern, Middle, and Northern Sacramento Valley were designed to provide statistically robust assessments of the quality of untreated groundwater in the primary aquifer systems that are used for drinking-water supply. The assessments are based on water-quality data collected by the USGS from 235 wells in the three study units in 2005-08, and water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer systems (hereinafter, referred to as primary aquifers) assessed in this study are defined by the depth intervals of the wells in the CDPH database for each study unit. The quality of groundwater in shallow or deep water-bearing zones may differ from quality of groundwater in the primary aquifers; shallow groundwater may be more vulnerable to contamination from the surface. The status of the current quality of the groundwater resource was assessed by using data from samples analyzed for volatile organic

  6. Environmental risk assessment in five rivers of Parana River basin, Southern Brazil, through biomarkers in Astyanax spp.

    Science.gov (United States)

    Barros, Ivaldete Tijolin; Ceccon, Juliana Parolin; Glinski, Andressa; Liebel, Samuel; Grötzner, Sonia Regina; Randi, Marco Antonio Ferreira; Benedito, Evanilde; Ortolani-Machado, Claudia Feijó; Filipak Neto, Francisco; de Oliveira Ribeiro, Ciro Alberto

    2017-07-01

    In the current study, water quality of five river sites in Parana River basin (Brazil), utilized for public water supply, was assessed through a set of biomarkers in fish Astyanax spp. Population growth and inadequate use of land are challenges to the preservation of biodiversity and resources such as water. Some physicochemical parameters as well as somatic indexes, gills and liver histopathology, genotoxicity, and biochemical biomarkers were evaluated. The highest gonadosomatic index (GSI) and antioxidant parameters (catalase and glutathione S-transferase activities, non-protein thiols), as well as the lowest damage to biomolecules (lipid peroxidation, protein carbonylation, DNA damage) were observed in site 0 (Piava River), which is located at an environmental protected area. Site 1, located in the same river, but downstream site 0 and outside the protection area, presents some level of impact. Fish from site 2 (Antas River), which lack of riparian forest and suffer from silting, presented the highest micronucleus incidence and no melanomacrophages. Differently, individuals from site 3 (Xambrê River) and site 4 (Pinhalzinho River) which receive surface runoff from Umuarama city, urban and industrial sewage, have the highest incidences of liver and gill histopathological alterations, including neoplasia, which indicated the worst health conditions of all sites. In particular, site 4 had high levels of total nitrogen and ammonia, high turbidity, and very low oxygen levels, which indicate important chemical impact. Comparison of the biomarkers in fish allowed classification of the five sites in terms of environmental impact and revealed that sites 3 and 4 had particular poor water quality.

  7. Evaluation of the Tindouf Basin Region in Southern Morocco as an Analog Site for Soil Geochemistry on Noachian Mars.

    Science.gov (United States)

    Oberlin, Elizabeth A; Claire, Mark W; Kounaves, Samuel P

    2018-02-09

    Locations on Earth that provide insights into processes that may be occurring or may have occurred throughout martian history are often broadly deemed "Mars analog environments." As no single locale can precisely represent a past or present martian environment, it is important to focus on characterization of terrestrial processes that produce analogous features to those observed in specific regions of Mars or, if possible, specific time periods during martian history. Here, we report on the preservation of ionic species in soil samples collected from the Tindouf region of Morocco and compare them with the McMurdo Dry Valleys of Antarctica, the Atacama Desert in Chile, the martian meteorite EETA79001, and the in situ Mars analyses from the Phoenix Wet Chemistry Laboratory (WCL). The Moroccan samples show the greatest similarity with those from Victoria Valley, Beacon Valley, and the Atacama, while being consistently depleted compared to University Valley and enriched compared to Taylor Valley. The NO 3 /Cl ratios are most similar to Victoria Valley and Atacama, while the SO 4 /Cl ratios are similar to those from Beacon Valley, Victoria Valley, and the Atacama. While perchlorate concentrations in the Moroccan samples are typically lower than those found in samples of other analog sites, conditions in the region are sufficiently arid to retain oxychlorines at detectable levels. Our results suggest that the Tindouf Basin in Morocco can serve as a suitable analogue for the soil geochemistry and subsequent aridification of the Noachian epoch on Mars. Key Words: Mars analogues-Antarctica-Morocco-Oxyanions-Perchlorate-Nitrate. Astrobiology 18, xxx-xxx.

  8. The Educational System of Peru.

    Science.gov (United States)

    Nemeth, Edward J.

    An overview of the basic system of education in Peru is presented. Despite various achievements in education, Peruvian authorities in recent years generally have not considered educational progress sufficient to meet the social and economic needs of their society. As a result, two educational structures are presently operating in Peru. The…

  9. Changing Girls' Education in Peru.

    Science.gov (United States)

    Heyman, Cory; Brush, Lorie; Provasnik, Stephen; Fanning, Marina; Lent, Drew; De Wilde, Johan

    Access to quality education is a problem for all rural children in Peru, but especially for rural girls, who complete primary school at far lower rates than other Peruvian children. In 1998, USAID launched the Girls' Education Activity (GEA) in Peru, also known as New Horizons for Girls' Education, which aims to increase girls' completion of…

  10. Neogene biogenic sediments of onshore Peru. Part 2. Geochemistry and diagenesis

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P.A.; Dunbar, R.B.; Marty, R.C.

    1985-01-01

    The Neogene sediments of coastal Peru are comprised in part of biogenic silica, phosphorites, and authigenic dolomites. The authors have studied these sediments in the Pisco Basin of southern Peru. In this region the sediments have escaped large-scale post-depositional structural or thermal overprinting. The phosphorites of the Middle Member of the Miocene Pisco Formation occur as 5 to 10 cm. thick beds of phosphatic sediments separated by meters of siliceous, tuffaceous, or dolomitic muds and silts. The phosphatic grains are usually colitic and the depositions are often channeled and reworked on a small scale. Many of these colitic beds disconformably overlie phosphatized dolomitic beds. The dolomites of the Pisco Formation occur as authigenic beds and nodules a few centimeters to over one meter in diameter. They occur at intervals of one to tens of meters. The dolomites are well-ordered and calcite-free. The mole percent calcium varies from 47.3 to 57.4, iron from 0.12 to 2.18, and manganese from 0.03 to 0.62. Strontium varies from 90 to 837 ppm, zinc from 12 to 124 ppm, and sulfate from 100 to 2000 ppm. The carbon isotopic composition of the Pisco dolomites is usually negative, varying from +7.05 to -21.86 per mil PDB. The oxygen isotopic compositions vary from -0.18 to +4.16 per mil PDB. These chemical signatures are consistent with rapid authigenic formation of the dolomite: (1) within a few meters of the sea floor, (2) at shallow water depths, (3) in sediments undergoing microbial sulfate reduction but in the presence of some dissolved sulfate, and (4) in the absence of thermal or fresh water diagenetic overprinting.

  11. 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).

  12. 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

  13. Integrated geophysical studies on the area east of Abu Gharadig basin, southern Cairo, Egypt, using potential field data

    Science.gov (United States)

    El-Awady, Mohammed Mohamed; El-Badrawy, Hussein Tawfek; Abuo El-Ela, Amin Mohamed; Solimaan, Mohamed Refaat; Alrefaee, Hamed Abdelhamid; Elbowab, Mostafa

    2016-12-01

    Potential field data of the area east of Abu Gharadig basin were used to delineate the tectonic framework of probable economic interest and for future development plans for the area. To achieve this goal, the RTP and Bouguer gravity maps of the study area were subjected to several filtering and processing techniques. The regional magnetic map shows NE-SW high regional magnetic trends at the northwestern and southeastern parts as well as low magnetic trends at the central part reflecting thick non-magnetized sediments and/or deep highly magnetized basement rocks. Similarly, the regional gravity map shows NE-SW diagonal high and low gravity trends across the entire area of study as well as a distinct increase of gravity values toward the northwest corner reflecting thickening of sedimentary cover and/or deepening of denser basement rock at the central part. The residual maps reveal many anomalies of shallow sources with different polarities, amplitudes and extensions in the form of alternating high and low gravity and magnetic indicating that the basement rocks are dissected by faults forming uplifted and downthrown blocks. Edge detection techniques outlined effectively the boarders and extensions of the structural highs and lows through showing gravity and magnetic maxima over the edges of these tectonic features. Moreover, the River Nile course is controlled by shallow normal faults affecting the recent Nile sediments and is clearly shown by edge detection maps of gravity data. Euler deconvolution of magnetic and gravity data reveals clustering of solution along fault trends or causative bodies centers. The Euler depth estimate to the basement surface shows a good correlation with the depth determined by the power spectrum method where its value ranges around 4 km. The interpreted basement tectonic map of the study area is dominated by ENE-WSW Syrian Arc, NW-SE Gulf of Suez and Red Sea, NE-SW Aqaba, E-W Mediterranean and N-S East Africa tectonic trends. The older

  14. [Fertility transition in Peru].

    Science.gov (United States)

    Ferrando, D; Aramburu, C E

    1992-12-01

    Data from national censuses and sample surveys are the basis for this examintion of differential fertility and the fertility transition in Peru. Changes in the level and structure of fertility in the 3 major geographic regions are compared, and the role of contraceptive usage and nuptiality changes in the fertility decline are analyzed. Peru's total fertility rate was estimated at 6.85 in 1965 and has since declined to 6.56 in 1965-70, 6.00 in 1970-75, 5.30 in 1975-80, 4.65 in 1980-85, and 4.00 in 1985-90. The fertility decline varied in intensity and timing in the geographic regions. A clear fertility decline began among upper and middle income groups in the principal cities in the 1960s, spreading gradually to the urban low income sectors. Not until the late 1970s did the fertility decline spread to the rest of the population, coinciding with the years of severe economic crisis. The urban total fertility rate declined from 6 to 3.77 during 1961-86, but rural fertility increased through 1972 to 8.12, before declining slightly to 7.62 in 1981 and more markedly to 6.65 in 1986. Sociocultural and economic differences between Peru's natural regions are appreciable, and account for the contrasts in fertility trends. The greatest changes occurred in metropolitan Lima, which already had relatively low fertility in 1961. Its total fertility rate declined 44% from 5.6 in 1961 to 3.13 in 1986. Fertility declined by slightly under 40% in the rest of the coast, by almost 25% in the jungle, and by scarcely 14% in the sierra. The total fertility rates in 1961 and 1986, respectively, were 6.38 and 4.13 on the coast, 6.64 and 6.45 in the highlands, and 7.92 and 5.97 in the lowlands. The fertility decline, especially in the lower classes, was a response initially to the process of cultural modernization which in slightly over 2 decades saw a profound transformation of Peru from a rural, Andean, illiterate, and agrarian society to an urban, coastal, literate, and commercial society

  15. 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

  16. Basaltic lava flows covering active aeolian dunes in the Paraná Basin in southern Brazil: Features and emplacement aspects

    Science.gov (United States)

    Waichel, Breno L.; Scherer, Claiton M. S.; Frank, Heinrich T.

    2008-03-01

    Burial of active aeolian dunes by lava flows can preserve the morphology of the dunes and generate diverse features related to interaction between unconsolidated sediments and lavas. In the study area, located in southern Brazil, burial of aeolian deposits by Cretaceous basaltic lava flows completely preserved dunes, and generate sand-deformation features, sand diapirs and peperite-like breccia. The preserved dunes are crescentic and linear at the main contact with basalts, and smaller crescentic where interlayered with lavas. The various feature types formed on sediment surfaces by the advance of the flows reflect the emplacement style of the lavas which are compound pahoehoe type. Four feature types can be recognized: (a) type 1 features are related to the advance of sheet flows in dune-interdune areas with slopes > 5°, (b) type 2 is formed where the lava flows advance in lobes and climb the stoss slope of crescentic dunes (slopes 8-12°), (c) type 3 is generated by toes that descend the face of linear dunes (slopes 17-23°) and (d) type 4 occurs when lava lobes descend the stoss slope of crescentic dunes (slopes 10-15°). The direction of the flows, the disposition and morphology of the dunes and the ground slope are the main factors controlling formation of the features. The injection of unconsolidated sand in lava lobes forms diapirs and peperite-like breccias. Sand diapirs occur at the basal portion of lobes where the lava was more solidified. Peperite-like breccias occur in the inner portion where lava was more plastic, favoring the mingling of the components. The generation of both features is related to a mechanical process: the weight of the lava causes the injection of sand into the lava and the warming of the air in the pores of the sand facilitates this process. The lava-sediment interaction features presented here are consistent with previous reports of basalt lavas with unconsolidated arid sediments, and additional new sand-deformation features

  17. 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.

  18. Implementation of a subcanopy solar radiation model on a forested headwater basin in the Southern Appalachians to estimate riparian canopy density and stream insolation for stream temperature models

    Science.gov (United States)

    Belica, L.; Petras, V.; Iiames, J. S., Jr.; Caldwell, P.; Mitasova, H.; Nelson, S. A. C.

    2016-12-01

    Water temperature is a key aspect of water quality and understanding how the thermal regimes of forested headwater streams may change in response to climatic and land cover changes is increasingly important to scientists and resource managers. In recent years, the forested mountain watersheds of the Southeastern U.S. have experienced changing climatic patterns as well as the loss of a keystone riparian tree species and anticipated hydrologic responses include lower summer stream flows and decreased stream shading. Solar radiation is the main source of thermal energy to streams and a key parameter in heat-budget models of stream temperature; a decrease in flow volume combined with a reduction in stream shading during summer have the potential to increase stream temperatures. The high spatial variability of forest canopies and the high spatio-temporal variability in sky conditions make estimating the solar radiation reaching small forested headwater streams difficult. The Subcanopy Solar Radiation Model (SSR) (Bode et al. 2014) is a GIS model that generates high resolution, spatially explicit estimates of solar radiation by incorporating topographic and vegetative shading with a light penetration index derived from leaf-on airborne LIDAR data. To evaluate the potential of the SSR model to provide estimates of stream insolation to parameterize heat-budget models, it was applied to the Coweeta Basin in the Southern Appalachians using airborne LIDAR (NCALM 2009, 1m resolution). The LIDAR derived canopy characteristics were compared to current hyperspectral images of the canopy for changes and the SSR estimates of solar radiation were compared with pyranometer measurements of solar radiation at several subcanopy sites during the summer of 2016. Preliminary results indicate the SSR model was effective in identifying variations in canopy density and light penetration, especially in areas associated with road and stream corridors and tree mortality. Current LIDAR data and

  19. 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

  20. 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).

  1. 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.

  2. 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

  3. 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

  4. New species and host plants of Anastrepha (Diptera: Tephritidae) primarily from Peru and Bolivia

    Science.gov (United States)

    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), ...

  5. 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.

  6. Peru turnaround tied to privatization

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Petroleos del Peru predicts a 10% increase in Peru's oil production this year and a further increase in 1994. Petroperu also forecasts a sharp increase in drilling in Peru this year. After several years of declining oil production, a gradual turnaround in the cash strapped country's petroleum industry is largely tied to its progress in privatization. The government last year began a campaign to privatize all state owned companies by the end of July 1995. The paper discusses forecasts by Petroperu; the contract of Occidental del Amazonas Inc.; the Petromar privatization; Great Western's contract; development of the Aguaytia gas field; and refinery contracts

  7. Crustal structure and tectonic deformation of the southern Ecuadorian margin

    Science.gov (United States)

    Calahorrano, Alcinoe; Collot, Jean-Yves; Sage, Françoise; Ranero, César R.

    2010-05-01

    Multichannel seismic lines acquired during the SISTEUR cruise (2000) provide new constraints on the structure and deformation of the subduction zone at the southern Ecuadorian margin, from the deformation front to the continental shelf of the Gulf of Guayaquil. The pre-stack depth migrated images allows to characterise the main structures of the downgoing and overriding plates and to map the margin stratigraphy in order to propose a chronology of the deformation, by means of integrating commercial well data and industry seismic lines located in the gulf area. The 100-km-long seismic lines show the oceanic Nazca plate underthrusting the South American plate, as well as the subduction channel and inter-plate contact from the deformation front to about 90 km landward and ~20 km depth. Based on seismic structure we identify four upper-plate units, consisting of basement and overlaying sedimentary sequences A, B and C. The sedimentary cover varies along the margin, being few hundreds of meters thick in the lower and middle slope, and ~2-3 km thick in the upper slope. Exceptionally, a ~10-km -thick basin, here named Banco Peru basin, is located on the upper slope at the southernmost part of the gulf. This basin seems to be the first evidence of the Gulf of Guayaquil opening resulting from the NE escaping of the North Andean Block. Below the continental shelf, thick sedimentary basins of ~6 to 8 km occupy most of the gulf area. Tectonic deformation across most of the upper-plate is dominated by extensional regime, locally disturbed by diapirism. Compression evidences are restricted to the deformation front and surrounding areas. Well data calibrating the seismic profiles indicate that an important portion of the total thickness of the sedimentary coverage of the overriding plate are Miocene or older. The data indicate the extensional deformation resulting from the NE motion of the North Andean Block and the opening of the Gulf of Guayaquil, evolves progressively in age

  8. 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.

  9. 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.

  10. May 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...

  11. 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

  12. 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

  13. New stratigraphic, chronologic, and magnetic fabric constraints for Neogene and Quaternary ignimbrites in the Central Andes (South Peru)

    Science.gov (United States)

    De La Rupelle, A.; Thouret, J. C.; Cubukcu, H. E.; Jicha, B.; Bréard, E.; Gerbe, M.-C.; Le Pennec, J.-L.; Diot, H.; Boivin, P.

    2012-04-01

    Central Andean deformation history in southern Peru is recorded in Neogene volcanic units of Ocoña and Cotahuasi canyons that cut across the western Cordillera. Acceleration (100 km3) Nazca (c.24.6 Ma), Alpabamba (19.4-18.0 Ma), and Huaylillas (14.25-12.7 Ma) ignimbrite sheets preceded the canyon incision, whereas sheets of smaller volume (Peru, stratigraphy, chronology, AMS, fabric, Neogene, Quaternary.

  14. The upper lithostratigraphic unit of ANDRILL AND-2A core (Southern McMurdo Sound, Antarctica): local Pleistocene volcanic sources, paleoenvironmental implications and subsidence in the southern Victoria Land Basin

    Science.gov (United States)

    Del Carlo, P.; Panter, K. S.; Bassett, K. N.; Bracciali, L.; di Vincenzo, G.; Rocchi, S.

    2009-12-01

    We report results from the study of the uppermost 37 meters of the Southern McMurdo Sound (SMS) AND-2A drillcore, corresponding to the lithostratigraphic unit 1 (LSU 1), the most volcanogenic unit within the core. Nearly all of LSU 1 consists of volcanic breccia and sandstone that is a mixture of near primary volcanic material dominated by lava and vitric clasts with minor exotic material derived from distal basement sources. Lava clasts and glass are mafic and range from strongly alkaline (basanite, tephrite) to moderately alkaline (alkali basalt, hawaiite) compositions that are similar to nearby land deposits. 40Ar-39Ar laser step-heating analyses on groundmass separated from lava clasts yield Pleistocene ages (692±38 and 793±63, ±2σ internal errors). Volcanoes of the Dailey Island group, located ~13 km SW of the drillsite, are a possible source for the volcanic materials based on their close proximity, similar composition and age. A basanite lava flow on Juergens Island yields a comparable Pleistocene age of 775±22 ka. Yet there is evidence to suggest that the volcanic source is much closer to the drillsite and that the sediments were deposited in much shallower water relative to the present-day water depth of 384 mbsl. Evidence for local volcanic activity is based in part on the common occurrence of delicate vitriclasts (e.g. glass shards and Pele’s hair) and a minimally reworked ~2 meter thick monomict breccia that is interpreted to have formed by autobrecciating lava. In addition, conical-shaped seamounts and high frequency magnetic anomalies encompass the drillsite and extend south including the volcanoes of the Dailey Islands. Sedimentary features and structures indicate shallow water sedimentation for the whole of LSU 1. Rippled asymmetric cross-laminated sands and hummocky cross-stratification occur intermittently throughout LSU 1 and indicate water depths shallower than 100 meters. The occurrence of ooliths and layers containing siderite and Fe

  15. 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.

  16. 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

  17. 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

  18. New insight on the recent tectonic evolution and uplift of the southern Ecuadorian Andes from gravity and structural analysis of the Neogene-Quaternary intramontane basins

    Science.gov (United States)

    Tamay, J.; Galindo-Zaldívar, J.; Ruano, P.; Soto, J.; Lamas, F.; Azañón, J. M.

    2016-10-01

    The sedimentary basins of Loja, Malacatos-Vilcabamba and Catamayo belong to the Neogene-Quaternary synorogenic intramontane basins of South Ecuador. They were formed during uplift of the Andes since Middle-Late Miocene as a result of the Nazca plate subduction beneath the South American continental margin. This E-W compressional tectonic event allowed for the development of NNE-SSW oriented folds and faults, determining the pattern and thickness of sedimentary infill. New gravity measurements in the sedimentary basins indicate negative Bouguer anomalies reaching up to -292 mGal related to thick continental crust and sedimentary infill. 2D gravity models along profiles orthogonal to N-S elongated basins determine their deep structure. Loja Basin is asymmetrical, with a thickness of sedimentary infill reaching more than 1200 m in the eastern part, which coincides with a zone of most intense compressive deformation. The tectonic structures include N-S, NW-SE and NE-SW oriented folds and associated east-facing reverse faults. The presence of liquefaction structures strongly suggests the occurrence of large earthquakes just after the sedimentation. The basin of Malacatos-Vilcabamba has some folds with N-S orientation. However, both Catamayo and Malacatos-Vilcabamba basins are essentially dominated by N-S to NW-SE normal faults, producing a strong asymmetry in the Catamayo Basin area. The initial stages of compression developed folds, reverse faults and the relief uplift determining the high altitude of the Loja Basin. As a consequence of the crustal thickening and in association with the dismantling of the top of the Andes Cordillera, extensional events favored the development of normal faults that mainly affect the basins of Catamayo and Malacatos-Vilcabamba. Gravity research helps to constrain the geometry of the Neogene-Quaternary sedimentary infill, shedding some light on its relationship with tectonic events and geodynamic processes during intramontane basin

  19. Asymmetrical, inversely graded, upstream-migrating cyclic steps in marine settings: Late Miocene-early Pliocene Fish Creek-Vallecito Basin, southern California

    Science.gov (United States)

    Gong, Chenglin; Chen, Liuqin; West, Logan

    2017-10-01

    Cyclic steps are ubiquitous in modern sedimentary environments, yet their recognition remains sparse in the rock record. Here, we interpret three sets of undulating backsets (1 to 3) recognized in the late Miocene-early Pliocene Latrania Formation in the Anza-Borrego Desert, the Fish Creek-Vallecito Basin, southern California, USA as the first cm- to dm-scale outcrop record of cyclic steps, based on asymmetrical cross-sections, upstream migration, and inversely graded laminae. Upstream migration and asymmetrical cross-sections of backsets and concomitant backset laminae are attributed to supercritical-to-subcritical flow transitions through weak hydraulic jumps, which are composed of: (i) thin (tens of centimetres) and slower (reported as flow velocities (Ū) of 0.45 to 1.45 m s- 1, with mean value of Ū = 0.89 m s- 1) subcritical (represented by internal Froude numbers (Fr) of 0.67 to 0.99, with mean value of Fr = 0.84) turbidity currents on the stoss sides, and (ii) thin (tens of centimetres) and faster (reported as Ū of 0.99 to 4.03 m s- 1, with mean value of Ū = 2.24 m s- 1) supercritical (represented by Fr of 1.84 to 3.07, with mean value of Fr = 2.42) turbidity flows on the lee sides. The inversely graded laminae in the troughs of backsets are 2 to 5 cm thick, and consist of two discrete divisions: (i) 1 to 2 cm thick, lower finer-grained divisions made up of parallel laminated siltstones, overlain by very fine- to fine-grained sandstones, and (ii) 2 to 3 cm thick, upper divisions composed of medium- to coarse-grained sandstones, with sporadic occurrence of subrounded pebbles. These inversely graded laminae are related to stratified, collisional and/or frictional traction carpets under conditions of high fall-out rates. Due to the poor preservation potential of cyclic steps, the rock record of cyclic steps is generally considered to be rare. The present outcrop-based study presents a detailed analysis of sedimentary facies, growth patterns, and flow

  20. Petro-geochemical constraints on the source and evolution of magmas at El Misti volcano (Peru)

    OpenAIRE

    Rivera, M.; Martin, H.; Le Pennec, Jean-Luc; Thouret, J. C.; Gourgaud, A.; Gerbe, M. C.

    2017-01-01

    El Misti volcano, a large and hazardous edifice of the Andean Central Volcanic Zone (CVZ) of southern Peru, consists of four main growth stages. Misti 1 (>112 ka) is an old stratovolcano partly concealed by two younger stratocones (Misti 2, 112-40 ka; Misti 3, 38-11 ka), capped in turn by a recent summit cone (Misti 4,

  1. 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

    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

  2. A reassessment of the suspended sediment load in the Madeira River basin from the Andes of Peru and Bolivia to the Amazon River in Brazil, based on 10 years of data from the HYBAM monitoring programme

    Science.gov (United States)

    Vauchel, Philippe; Santini, William; Guyot, Jean Loup; Moquet, Jean Sébastien; Martinez, Jean Michel; Espinoza, Jhan Carlo; Baby, Patrice; Fuertes, Oscar; Noriega, Luis; Puita, Oscar; Sondag, Francis; Fraizy, Pascal; Armijos, Elisa; Cochonneau, Gérard; Timouk, Franck; de Oliveira, Eurides; Filizola, Naziano; Molina, Jorge; Ronchail, Josyane

    2017-10-01

    The Madeira River is the second largest tributary of the Amazon River. It contributes approximately 13% of the Amazon River flow and it may contribute up to 50% of its sediment discharge to the Atlantic Ocean. Until now, the suspended sediment load of the Madeira River was not well known and was estimated in a broad range from 240 to 715 Mt yr-1. Since 2002, the HYBAM international network developed a new monitoring programme specially designed to provide more reliable data than in previous intents. It is based on the continuous monitoring of a set of 11 gauging stations in the Madeira River watershed from the Andes piedmont to the confluence with the Amazon River, and discrete sampling of the suspended sediment concentration every 7 or 10 days. This paper presents the results of the suspended sediment data obtained in the Madeira drainage basin during 2002-2011. The Madeira River suspended sediment load is estimated at 430 Mt yr-1 near its confluence with the Amazon River. The average production of the Madeira River Andean catchment is estimated at 640 Mt yr-1 (±30%), the corresponding sediment yield for the Andes is estimated at 3000 t km-2 yr-1 (±30%), and the average denudation rate is estimated at 1.20 mm yr-1 (±30%). Contrary to previous results that had mentioned high sedimentation rates in the Beni River floodplain, we detected no measurable sedimentation process in this part of the basin. On the Mamoré River basin, we observed heavy sediment deposition of approximately 210 Mt yr-1 that seem to confirm previous studies. But while these studies mentioned heavy sedimentation in the floodplain, we showed that sediment deposition occurred mainly in the Andean piedmont and immediate foreland in rivers (Parapeti, Grande, Pirai, Yapacani, Chimoré, Chaparé, Secure, Maniqui) with discharges that are not sufficiently large to transport their sediment load downstream in the lowlands.

  3. The role of post-collisional strike-slip tectonics in the geological evolution of the late Neoproterozoic volcano-sedimentary Guaratubinha Basin, southern Brazil

    Science.gov (United States)

    Barão, Leonardo M.; Trzaskos, Barbara; Vesely, Fernando F.; de Castro, Luís Gustavo; Ferreira, Francisco J. F.; Vasconcellos, Eleonora M. G.; Barbosa, Tiago C.

    2017-12-01

    The Guaratubinha Basin is a late Neoproterozoic volcano-sedimentary basin included in the transitional-stage basins of the South American Platform. The aim of this study is to investigate its tectonic evolution through a detailed structural analysis based on remote sensing and field data. The structural and aerogeophysics data indicate that at least three major deformational events affected the basin. Event E1 caused the activation of the two main basin-bounding fault zones, the Guaratubinha Master Fault and the Guaricana Shear Zone. These structures, oriented N20-45E, are associated with well-defined right-lateral to oblique vertical faults, conjugate normal faults and vertical flow structures. Progressive transtensional deformation along the two main fault systems was the main mechanism for basin formation and the deposition of thick coarse-grained deposits close to basin-borders. The continuous opening of the basin provided intense intermediate and acid magmatism as well as deposition of volcaniclastic sediments. Event E2 characterizes generalized compression, recorded as minor thrust faults with tectonic transport toward the northwest and left-lateral activation of the NNE-SSW Palmital Shear Zone. Event E3 is related to the Mesozoic tectonism associated with the South Atlantic opening, which generated diabase dykes and predominantly right-lateral strike-slip faults oriented N10-50W. Its rhomboidal geometry with long axis parallel to major Precambrian shear zones, the main presence of high-angle, strike-slip or oblique faults, the asymmetric distribution of geological units and field evidence for concomitant Neoproterozoic magmatism and strike-slip movements are consistent with pull-apart basins reported in the literature.

  4. 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…

  5. Nasca Lines, Peru

    Science.gov (United States)

    2001-01-01

    The Nasca Lines are located in the Pampa region of Peru, the desolate plain of the Peruvian coast 400 km south of Lima. The Lines were first spotted when commercial airlines began flying across the Peruvian desert in the 1920's. Passengers reported seeing 'primitive landing strips' on the ground below. The Lines were made by removing the iron-oxide coated pebbles which cover the surface of the desert. When the gravel is removed, they contrast with the light color underneath. In this way the lines were drawn as furrows of a lighter color. On the pampa, south of the Nasca Lines, archaeologists have now uncovered the lost city of the line-builders, Cahuachi. It was built nearly two thousand years ago and was mysteriously abandoned 500 years later. This ASTER sub-image covers an area of 14 x 18 km, was acquired on December 22, 2000, and is located at 14.7 degrees south latitude and 75.1 degrees west longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  6. Peru: population and policy.

    Science.gov (United States)

    Sobrevilla, L A

    1987-06-01

    Peru's 1985 Population Policy Law states as its second objective that individuals and couples should be well informed and provided with the education and health services that will assist them in making responsible decisions about the number and spacing of their children. Thus, the law establishes a firm basis for IEC programs. With regard to population education, the purpose of the law is to create awareness through all educational channels of the reciprocal influence of population dynamics and socioeconomic development and to promote positive attitudes toward small family size. The law promotes the use of the communications media to educate and inform about population issues. The National Population Council, which coordinates and supervises the IEC activities of public sector agencies, has issued publications and audiovisual materials, conducted meetings with government officials and opinion leaders, and promoted awareness of population policy as a key part of development planning. In 1984, the Council organized the First National Seminar on Communication and Population to review activities, set the basis for intersectoral coordination, unify criteria, and review population policy concepts and language. The Ministry of Health carries out IEC activities as part of its family planning services program. In addition, the Ministry of Education has organized a national population education program that aims to revise school curricula to include a greater emphasis on population dynamics and family life education. The activities of a number of private institutions complement the IEC work public sector organizations.

  7. [Bioethics in Peru].

    Science.gov (United States)

    Zuloaga, R L

    1990-01-01

    Bioethics has still not acquired an identity of its own in Peru. The Ethics Committee of the Peruvian Medical School and the National AIDS Commission are review committees that deal with ethical problems arising in practice. Doubts regarding quality control of the drugs being tested have been raised in research on human subjects. Questions related to reproduction are very important. There is a high incidence of adolescent pregnancies, and illegal abortions result in many deaths and hospitalizations of women in serious condition. Birth control methods, such as vasectomy, conflict with attitudes about manhood in Peruvian society. Euthanasia is prohibited by the Ethical Code of the Peruvian Medical School, and legislation penalizes assisted suicide. Organ transplantation is hindered by concerns over early declaration of death. Handicapped children are often rejected by society owing to an absurd belief in the possibility that disorders such as Down's syndrome are contagious. The Ministry of Health requires state hospitals to accept AIDS patients, but instances of rejection are still reported.

  8. Palaeofluid evolution in a fractured basalt hosted reservoir in the Ulles-Ruzsa-Bordany area, southern sector of the Pannonian Basin

    Czech Academy of Sciences Publication Activity Database

    Szabó, B.; Schubert, F.; Toth, T.M.; Steinbach, Gabor

    2016-01-01

    Roč. 69, č. 3 (2016), s. 281-293 ISSN 1330-030X Institutional support: RVO:61388971 Keywords : fractured basalt reservoir * Pannonian Basin * zeolite minerals Subject RIV: EE - Microbiology, Virology Impact factor: 0.595, year: 2016

  9. Vertical Profiles Of 226Ra, 232Th And 40K Activities In Rocks From The Irati Formation Of The Paraná Sedimentary Basin, Southern Brazil

    Science.gov (United States)

    Ferreira, Ademar de O.; Bastos, Rodrigo O.; Appoloni, Carlos R.

    2008-08-01

    Naturally occurring radioisotopes are present in different concentrations in sedimentary rocks, reflecting the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. Using a high-resolution γ-ray spectrometry methodology, sedimentary rocks were measured to assess the concentration activities of the natural radioisotopes. The surveyed rocks are from the Irati formation in the Paraná sedimentary basin, which are exposed by an abandoned, open-pit limestone mine, in the city of Sapopema, southern Brazil. The exposed vertical profile is 5 m, and its stratigraphy is represented by an alternation of limestone and bituminous shale (layers being a few decimeters thick), and some millimeter rhythm layers with limestone and bituminous shale laminas. Eleven samples were collected along this profile, each of them dried in the open air during 48 hours, sieved through 4 mm mesh and sealed in cylindrical recipients. Measurements were accomplished using a 66% relative efficiency HPGE detector connected to a standard gamma ray spectrometry electronic chain. The detector efficiency in the range of 60 to 1800 keV was carried out with the certified IAEA-385 sediment sample. The Lower Limit of Detection (LLD) to the system is 2.40 Bqṡkg-1 for 226Ra, 1.84 Bqṡkg-1 for 232Th and 4.20 Bqṡkg-1 for 40K. Activity concentrations were determined for 226Ra (from 16.22 to 151.55 Bqṡkg-1), 232Th (from 2.93 to 56.12 Bqṡkg-1) and 40K (from 38.45 to 644.63 Bqṡkg-1). The layers enriched with organic matter presented the higher values of activity. The measured concentrations of the natural radioisotopes were lower for limestone samples (average values and respective deviations were 22.81±0.22 Bqṡkg-1 for 226Ra, 4.21±0.07 Bqṡkg-1 for 232Th, and 50.11±0.82 Bqṡkg-1 for 40K). Higher concentrations were measured for the bituminous shale samples (average values and respective deviations were 108.10±12.17 Bqṡkg-1 for 226Ra, 43.69

  10. Vertical Profiles Of 226Ra, 232Th And 40K Activities In Rocks From The Irati Formation Of The Parana Sedimentary Basin, Southern Brazil

    International Nuclear Information System (INIS)

    Ferreira, Ademar de O.; Bastos, Rodrigo O.; Appoloni, Carlos R.

    2008-01-01

    Naturally occurring radioisotopes are present in different concentrations in sedimentary rocks, reflecting the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. Using a high-resolution γ-ray spectrometry methodology, sedimentary rocks were measured to assess the concentration activities of the natural radioisotopes. The surveyed rocks are from the Irati formation in the Parana sedimentary basin, which are exposed by an abandoned, open-pit limestone mine, in the city of Sapopema, southern Brazil. The exposed vertical profile is 5 m, and its stratigraphy is represented by an alternation of limestone and bituminous shale (layers being a few decimeters thick), and some millimeter rhythm layers with limestone and bituminous shale laminas. Eleven samples were collected along this profile, each of them dried in the open air during 48 hours, sieved through 4 mm mesh and sealed in cylindrical recipients. Measurements were accomplished using a 66% relative efficiency HPGE detector connected to a standard gamma ray spectrometry electronic chain. The detector efficiency in the range of 60 to 1800 keV was carried out with the certified IAEA-385 sediment sample. The Lower Limit of Detection (LLD) to the system is 2.40 Bq·kg -1 for 226 Ra, 1.84 Bq·kg -1 for 232 Th and 4.20 Bq·kg -1 for 40 K. Activity concentrations were determined for 226 Ra (from 16.22 to 151.55 Bq·kg -1 ), 232 Th (from 2.93 to 56.12 Bq·kg -1 ) and 40 K (from 38.45 to 644.63 Bq·kg -1 ). The layers enriched with organic matter presented the higher values of activity. The measured concentrations of the natural radioisotopes were lower for limestone samples (average values and respective deviations were 22.81±0.22 Bq·kg -1 for 226 Ra, 4.21±0.07 Bq·kg -1 for 232 Th, and 50.11±0.82 Bq·kg -1 for 40 K). Higher concentrations were measured for the bituminous shale samples (average values and respective deviations were 108.10±12.17 Bq·kg -1 for

  11. Itaya virus, a Novel Orthobunyavirus Associated with Human Febrile Illness, Peru

    Science.gov (United States)

    Hontz, Robert D.; Guevara, Carolina; Halsey, Eric S.; Silvas, Jesus; Santiago, Felix W.; Widen, Steven G.; Wood, Thomas G.; Casanova, Wilma; Vasilakis, Nikos; Watts, Douglas M.; Kochel, Tadeusz J.; Ebihara, Hideki

    2015-01-01

    Our genetic analyses of uncharacterized bunyaviruses isolated in Peru identified a possible reassortant virus containing small and large gene segment sequences closely related to the Caraparu virus and a medium gene segment sequence potentially derived from an unidentified group C orthobunyavirus. Neutralization tests confirmed serologic distinction among the newly identified virus and the prototype and Caraparu strains. This virus, named Itaya, was isolated in 1999 and 2006 from febrile patients in the cities of Iquitos and Yurimaguas in Peru. The geographic distance between the 2 cases suggests that the Itaya virus could be widely distributed throughout the Amazon basin in northeastern Peru. Identification of a new Orthobunyavirus species that causes febrile disease in humans reinforces the need to expand viral disease surveillance in tropical regions of South America. PMID:25898901

  12. Itaya virus, a Novel Orthobunyavirus Associated with Human Febrile Illness, Peru.

    Science.gov (United States)

    Hontz, Robert D; Guevara, Carolina; Halsey, Eric S; Silvas, Jesus; Santiago, Felix W; Widen, Steven G; Wood, Thomas G; Casanova, Wilma; Vasilakis, Nikos; Watts, Douglas M; Kochel, Tadeusz J; Ebihara, Hideki; Aguilar, Patricia V

    2015-05-01

    Our genetic analyses of uncharacterized bunyaviruses isolated in Peru identified a possible reassortant virus containing small and large gene segment sequences closely related to the Caraparu virus and a medium gene segment sequence potentially derived from an unidentified group C orthobunyavirus. Neutralization tests confirmed serologic distinction among the newly identified virus and the prototype and Caraparu strains. This virus, named Itaya, was isolated in 1999 and 2006 from febrile patients in the cities of Iquitos and Yurimaguas in Peru. The geographic distance between the 2 cases suggests that the Itaya virus could be widely distributed throughout the Amazon basin in northeastern Peru. Identification of a new Orthobunyavirus species that causes febrile disease in humans reinforces the need to expand viral disease surveillance in tropical regions of South America.

  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. 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,…

  15. Camisea: Peru in gassy state

    International Nuclear Information System (INIS)

    Cardenas Acosta, Liliana

    2005-01-01

    San Martin and Cashiriari fields, located to 500 kilometers to the southeast of Lima, conform the Camisea field that possesses the reserves more important of gas in Latin America. Camisea has gas and proven liquids of 13 quintillion cubic feet of natural gas and 600 million liquid barrels respectively. The paper includes projections, markets and benefits for the Peru

  16. Pseudotectites from Colombia and Peru

    NARCIS (Netherlands)

    Martin, R.; Sitter-Koomans, de C.

    1955-01-01

    In a previous note on “Americanites” (Martin, 1934) from Colombia and Peru, the writer came to the conclusion, on the basis solely of published data, that it was very likely that these so-called tectites are in reality obsidian of terrestrial origin. He stated, however, that “before it is possible

  17. The sea-air exchange of mercury (Hg) in the marine boundary layer of the Augusta basin (southern Italy): concentrations and evasion flux.

    Science.gov (United States)

    Bagnato, E; Sproveri, M; Barra, M; Bitetto, M; Bonsignore, M; Calabrese, S; Di Stefano, V; Oliveri, E; Parello, F; Mazzola, S

    2013-11-01

    The first attempt to systematically investigate the atmospheric mercury (Hg) in the MBL of the Augusta basin (SE Sicily, Italy) has been undertaken. In the past the basin was the receptor for Hg from an intense industrial activity which contaminated the bottom sediments of the Bay, making this area a potential source of pollution for the surrounding Mediterranean. Three oceanographic cruises have been thus performed in the basin during the winter and summer 2011/2012, where we estimated averaged Hgatm concentrations of about 1.5±0.4 (range 0.9-3.1) and 2.1±0.98 (range 1.1-3.1) ng m(-3) for the two seasons, respectively. These data are somewhat higher than the background Hg atm value measured over the land (range 1.1±0.3 ng m(-3)) at downtown Augusta, while are similar to those detected in other polluted regions elsewhere. Hg evasion fluxes estimated at the sea/air interface over the Bay range from 3.6±0.3 (unpolluted site) to 72±0.1 (polluted site of the basin) ng m(-2) h(-1). By extending these measurements to the entire area of the Augusta basin (~23.5 km(2)), we calculated a total sea-air Hg evasion flux of about 9.7±0.1 g d(-1) (~0.004 tyr(-1)), accounting for ~0.0002% of the global Hg oceanic evasion (2000 tyr(-1)). The new proposed data set offers a unique and original study on the potential outflow of Hg from the sea-air interface at the basin, and it represents an important step for a better comprehension of the processes occurring in the marine biogeochemical cycle of this element. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Mesozoic architecture of a tract of the European-Iberian continental margin: Insights from preserved submarine palaeotopography in the Longobucco Basin (Calabria, Southern Italy)

    Science.gov (United States)

    Santantonio, Massimo; Fabbi, Simone; Aldega, Luca

    2016-01-01

    The sedimentary successions exposed in northeast Calabria document the Jurassic-Early Cretaceous tectonic-sedimentary evolution of a former segment of the European-Iberian continental margin. They are juxtaposed today to units representing the deformation of the African and Adriatic plates margins as a product of Apenninic crustal shortening. A complex pattern of unconformities reveals a multi-stage tectonic evolution during the Early Jurassic, which affected the facies and geometries of siliciclastic and carbonate successions deposited in syn- and post-rift environments ranging from fluvial to deep marine. Late Sinemurian/Early Pliensbachian normal faulting resulted in exposure of the Hercynian basement at the sea-floor, which was onlapped by marine basin-fill units. Shallow-water carbonate aprons and reefs developed in response to the production of new accommodation space, fringing the newborn islands which represent structural highs made of Paleozoic crystalline and metamorphic rock. Their drowning and fragmentation in the Toarcian led to the development of thin caps of Rosso Ammonitico facies. Coeval to these deposits, a thick (> 1 km) hemipelagic/siliciclastic succession was sedimented in neighboring hanging wall basins, which would ultimately merge with the structural high successions. Footwall blocks of the Early Jurassic rift, made of Paleozoic basement and basin-margin border faults with their onlapping basin-fill formations, are found today at the hanging wall of Miocene thrusts, overlying younger (Middle/Late Jurassic to Late Paleogene) folded basinal sediments. This paper makes use of selected case examples to describe the richly diverse set of features, ranging from paleontology to sedimentology, to structural geology, which are associated with the field identification of basin-margin unconformities. Our data provide key constraints for restoring the pre-orogenic architecture of a continental margin facing a branch of the Liguria-Piedmont ocean in the

  19. Discussion on the genesis and mineralization of sandstone type uranium deposit in the southern-central Longchuanjiang basin, western Yunnan province

    International Nuclear Information System (INIS)

    Cai Yuqi; Li Mangen

    2002-01-01

    The author mainly discusses the character of the depositional systems, geological structures and ore-bearing series in the south-central Longchuanjiang basin, and points out that the uranium mineralization is closely related to the two depositional discontinuities caused by the tectonic evolution. Based on the characteristics of uranium mineralization in the area, pitchblende, uranium blacks and phosphuranylite are discovered in No. 382 uranium deposit and radiometric super-micro-minerals in No. 381 deposit. The research on the uranium mineralization age in No. 382 deposit shows that the mineralization in the south-central part of the basin has genetically multi-staged

  20. Assessment of hydrochemical trends in the highly anthropised Guadalhorce River basin (southern Spain) in terms of compliance with the European groundwater directive for 2015.

    Science.gov (United States)

    Urresti-Estala, Begoña; Gavilán, Pablo Jiménez; Pérez, Iñaki Vadillo; Cantos, Francisco Carrasco

    2016-08-01

    One of the key aspects introduced by the European Water Framework Directive 2000/60/EC (WFD) and developed by Groundwater Directive 2006/118/EC was the need to analyse pollution trends in groundwater bodies in order to meet the environmental objectives set in Article 4 WFD. According to this Directive, the main goal of "good status" should be achieved by the year 2015, and having reached this horizon, now is a suitable time to assess the changes that have taken place with the progressive implementation of the WFD. An extensive database is available for the Guadalhorce River basin, and this was used not only to identify in groundwater but also to draw real conclusions with respect to the degree of success in meeting the targets established for this main deadline (2015) The geographic and climate context of the Guadalhorce basin has facilitated the development of a variety of economic activities, but the one affecting the largest surface area is agriculture (which is practised on over 50 % of the river basin). The main environmental impacts identified in the basin aquifers arise from the widespread use of fertilisers and manures, together with the input of sewage from population centres. In consequence, some of the groundwater bodies located in the basin have historically had very high nitrate concentrations, often exceeding 200 mg/L. In addition, return flows, the use of fertilisers and other pressures promote the entry of other pollutants into the groundwater, as well as the salinisation of the main aquifers in the basin. In order to assess the hydrochemical changes that have taken place since the entry into force of the WFD, we performed a detailed trends analysis, based on data from the official sampling networks. In some cases, over 35 years of water quality data are available, but these statistics also present significant limitations, due to some deficiencies in the design or management; thus, data are missing for many years, the results are subject to

  1. The Southern Ocean Observing System

    OpenAIRE

    Rintoul, Stephen R.; Meredith, Michael P.; Schofield, Oscar; Newman, Louise

    2012-01-01

    The Southern Ocean includes the only latitude band where the ocean circles the earth unobstructed by continental boundaries. This accident of geography has profound consequences for global ocean circulation, biogeochemical cycles, and climate. The Southern Ocean connects the ocean basins and links the shallow and deep limbs of the overturning circulation (Rintoul et al., 2001). The ocean's capacity to moderate the pace of climate change is therefore influenced strongly by the Southern Ocean's...

  2. Cenozoic sedimentation and exhumation of the foreland basin system preserved in the Precordillera thrust belt (31-32°S), southern central Andes, Argentina

    Science.gov (United States)

    Levina, Mariya; Horton, Brian K.; Fuentes, Facundo; Stockli, Daniel F.

    2014-09-01

    Andean retroarc compression associated with subduction and shallowing of the oceanic Nazca plate resulted in thin-skinned thrusting that partitioned and uplifted Cenozoic foreland basin fill in the Precordillera of west-central Argentina. Evolution of the central segment of the Precordillera fold-thrust belt is informed by new analyses of clastic nonmarine deposits now preserved in three intermontane regions between major east directed thrust faults. We focus on uppermost Oligocene-Miocene basin fill in the axial to frontal Precordillera at 31-32°S along the Río San Juan (Albarracín and Pachaco sections) and the flank of one of the leading thrust structures (Talacasto section). The three successions record hinterland construction of the Frontal Cordillera, regional arc volcanism, and initial exhumation of Precordillera thrust sheets. Provenance changes recorded by detrital zircon U-Pb age populations suggest that initial shortening in the Frontal Cordillera coincided with an early Miocene shift from eolian to fluvial accumulation in the adjacent foreland basin. Upward coarsening of fluvial deposits and increased proportions of Paleozoic clasts reflect cratonward (eastward) advance of deformation into the Precordillera and resultant structural fragmentation of the foreland basin into isolated intermontane segments. Apatite (U-Th)/He thermochronometry of basin fill constrains to 12-9 Ma the most probable age of uplift-induced exhumation and cooling of Precordillera thrust sheets. This apparent pulse of exhumation is evident in each succession, suggestive of rapid, large-scale exhumation by synchronous thrusting above a single décollement linking major structures of the Precordillera.

  3. Foreign oil companies weathering Peru's political crisis

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that foreign oil companies are weathering Peru's political crisis, and the outlook for increased foreign participation in Peru's petroleum sector remains promising. There has been improvement in the political turmoil and soured international relations that followed President Alberto Fujimori's Apr. 5 suspension of Peru's Congress, charging political corruption and attempts to block his fiscal reforms. But there are fresh concerns over an increase in terrorism aimed at oil industry facilities by antigovernment guerrilla groups in Peru. Meanwhile, state-owned oil company Petroleos del Peru (Petroperu) continues efforts to sell assets as part of Fujimori's mandated privatization program. And foreign companies continue to grapple with uncertainty and bureaucratic red tape in chasing investment opportunities in Peru's beleaguered but opening petroleum sector

  4. Seasonally warmer and humid climates in a lower paleolatitude position of southern Brazil (Paraná Basin): new findings of the Lueckisporites virkkiae zone (late Cisuralian-Guadalupian) in the Serra do Rio do Rastro and neighboring localities

    Science.gov (United States)

    di Pasquo, Mercedes; Souza, Paulo A.; Kavali, Pauline Sabina; Felix, Cristina

    2018-03-01

    First palynological information from surface samples of the Serra Alta and Rio do Rasto formations (Passa Dois Group, Paraná Basin), exposed in the Serra do Rio do Rastro (White's Column) and Urubici regions in Santa Catarina State (Brazil) is presented. The Serra Alta Formation is transitionally deposited over the Irati Formation, which is constrained to the late Artinskian/Kungurian by different paleontological and radiometric data. Twelve productive samples (of forty) yielded fairly well preserved palynomorphs, dominated by striate and non striate bisaccate and asaccate pollen grains and subordinated trilete and monolete spores, monosaccate pollen grains and Botryococcus. Diagnostic species of the Lueckisporites virkkiae Zone (Artinskian-Guadalupian) in the Paraná Basin are recorded along with few species of Guadalupian-Lopingian age (e.g. Cladaitina veteadensis, Guttulapollenites hannonicus, Lophotriletes parryensis, Protohaploxypinus microcorpus, Staurosaccites quadrifidus, Weylandites cincinnatus). They support a Kungurian-?Roadian age for the Serra Alta, and a Capitanian (?Lopingian) age for the Rio do Rasto formations. Four samples from the Sete Quedas outcrop yielded scarce and poorly preserved specimens of Lueckisporites likely due to weathering. A statistic comparison among our assemblages and selected Permian palynozones and palynofloras from South America supports a closer correlation with the La Veteada Formation (Guadalupian-Lopingian) from western Argentina due to common occurrence of all the species, and with the Striatites Zone (late Artinskian-Kungurian) of the Chacoparaná Basin, and the I-S Zone Melo Formation in Uruguay. The botanical affinities of the palynomorphs from both assemblages indicate the presence of spores of hygro-mesophytic affinities along with meso-xerophyle pollen grains, which is in agreement with seasonally warmer and humid climates favored by a lower paleolatitude position. The presence of pyrite in some of the miospore

  5. 2D compositional modeling of petroleum generation, expulsion and migration in the Southern compartment of the Reconcavo Basin, Brazil; Modelisation compositionnelle 2D de la genese, expulsion et migration du petrole dans le compartiment sud du Bassin de Reconcavo, Bresil

    Energy Technology Data Exchange (ETDEWEB)

    Barroz Penteado, H.L. de

    1999-01-07

    The Reconcavo Basin is part of a rift formed between the Late Jurassic and the Early Cretaceous in northeastern Brazil. The objective of this thesis was the compositional modeling of petroleum generation, expulsion and migration along a cross-section in the Southern Compartment of the basin with the Temispack basin simulation software. A geochemical study of the lacustrine shales of the Gomo Member (Candelas Fm.) has been performed to determine their petroleum potential, the evolution of maturation with depth and changes in petroleum composition. Hydrogen indices of immature kerogens (400-850 mg/g TOC) were shown to be higher than those of whole rocks, thus indicating a retention of Rock-Eval pyrolysis products in the mineral matrix of these type I source rocks. Saturates (30-50% of organic extracts in the immature zone) increase both in absolute and in relative (60-80%) terms in the oil window (2000-2600 m) because of a partial secondary cracking of NSOs and aromatics. After having tested several scenarios of geodynamic evolution between the Aptian and the Oligocene, a variable thickness of post-rift sediments (maximum of 1200 m) has been shown to be necessary to calibrate maturity parameters. Petroleum migration has been modeled to understand migration pathways as well as the role of faults as drains. Thus, two petroleum migration systems have been identified for the Dom Joao and Cexis accumulations. Petroleum compositional variations have been modeled by coupling the processes of retention and secondary cracking. A good calibration of compositions was obtained with secondary cracking parameters for NSOs and aromatics which are close to those of the main primary cracking reaction of a type I kerogen, coupled with a retention of 50% of NSOs within the source rocks. (author)

  6. Peru Brand: a Nation under Construction?

    OpenAIRE

    Elder Cuevas-Calderón

    2016-01-01

    During the last decade Peru has experienced a euphoric rediscovery –pseudo revaluation as a country– due to its booming gastronomy, tourism and economic growth.In this context, the presentresearch uses semio-psychoanalytic and postcolonial theories to explain Peru’s social outlook regarding the concept of nation, its reunion with a non-existent identity and the construction of the idea of nation based on the marketing campaign titled the Peru Brand. Thus, Peru Brand, far from uniting all Peru...

  7. An astronomical observatory for Peru

    Science.gov (United States)

    del Mar, Juan Quintanilla; Sicardy, Bruno; Giraldo, Víctor Ayma; Callo, Víctor Raúl Aguilar

    2011-06-01

    Peru and France are to conclude an agreement to provide Peru with an astronomical observatory equipped with a 60-cm diameter telescope. The principal aims of this project are to establish and develop research and teaching in astronomy. Since 2004, a team of researchers from Paris Observatory has been working with the University of Cusco (UNSAAC) on the educational, technical and financial aspects of implementing this venture. During an international astronomy conference in Cusco in July 2009, the foundation stone of the future Peruvian Observatory was laid at the top of Pachatusan Mountain. UNSAAC, represented by its Rector, together with the town of Oropesa and the Cusco regional authority, undertook to make the sum of 300,000€ available to the project. An agreement between Paris Observatory and UNSAAC now enables Peruvian students to study astronomy through online teaching.

  8. Presence of Piscirickettsia salmonis in farmed trout (Oncorhynchus mykiss) in Junin, Peru

    OpenAIRE

    Yunis A., Jefferson; Anicama D., Jahir; Manchego S., Alberto; Sandoval C., Nieves

    2015-01-01

    This study aimed to determine the possible presence ofPiscirickettsia salmonis in farmed rainbow trout (Oncorhynchus mykiss) in the Mantaro river basin, Junin, Peru, by the indirect inmunofluorescence test (IFAT). Kidney and spleen samples were collected from 180 trout from three fish farms. All samples resulted negative to P. salmonis; however, some individuals showed clinical sings of disease as skin ulcer, melanosis, abdominal swelling and exophthalmoses. Also, in the internal organs was f...

  9. A new species of Hypostomus Lacépède, 1803 (Siluriformes: Loricariidae from the upper rio Paraná basin, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Fernando C. Jerep

    Full Text Available A new species of Hypostomus with large and spaced light roundish spots is described from the upper rio Paraná basin. Hypostomus multidens new species is distinguished from all remaining congeners with light spots on a darker background by two independent characters: the presence of teeth with two symmetrical cusps, and a high tooth number in each dentary (122267, mean 196.8 and premaxilla (115-260, mean 190.8.

  10. Fault-related CO2 degassing, geothermics, and fluid flow in southern California basins---Physiochemical evidence and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Boles, James R. [Univ. of California, Santa Barbara, CA (United States); Garven, Grant [Tufts Univ., Medford, MA (United States)

    2015-08-04

    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.

  11. Fault-Related CO2 Degassing, Geothermics, and Fluid Flow in Southern California Basins--Physiochemical Evidence and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Garven, Grant [Tufts Univ., Medford, MA (United States)

    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.

  12. Disease Vector Ecology Profile: Peru

    Science.gov (United States)

    1998-12-01

    mi) border), on the south by Chile (160 km (99 mi) border), and in the west by the Pacific Ocean (2,414 km (1,497 mi) coast). Peru consists of three...1993), Brazil (1993), Paraguay (1996) and Chile (1997). Two isolates of hantavirus were reported in late 1996 from the rice rat, Oligoryzomys...Simuliidae. Fauna de Agua Dulce de la Republica Argentina. 38. (Insecta, Diptera, Simuliidae), Fascicle 2, 304 pp. +78 pp. of unnumbered figures

  13. Birth Control in Lima, Peru

    OpenAIRE

    Hall, M. Francoise

    2014-01-01

    It was carried out a case study of pregnancies and contraceptive methods used by a random sample of 500 women in Lima, Peru . During the five years preceding the interview, the proportion of pregnancies ending in abortions was 19 , 20 and 15 % in the socio- economic middle and lower respectively upper levels . Although the percentage of induced abortions was admitted as low , the rate of abortions was considered relatively high , and it was thought that probably included many whose provocatio...

  14. APPLICATION OF WELL LOG ANALYSIS IN ASSESSMENT OF PETROPHYSICAL PARAMETERS AND RESERVOIR CHARACTERIZATION OF WELLS IN THE “OTH” FIELD, ANAMBRA BASIN, SOUTHERN NIGERIA

    Directory of Open Access Journals (Sweden)

    Eugene URORO

    2014-12-01

    Full Text Available Over the past years, the Anambra basin one of Nigeria’s inland basins has recorded significant level of hydrocarbon exploration activities. The basin has been confirmed by several authors from source rock analyses to have the potential for generating hydrocarbon. For the hydrocarbon to be exploited, it is imperative to have a thorough understanding of the reservoir. Computer-assisted log analyses were employed to effectively evaluate the petrophysical parameters such as the shale volume (Vsh, total porosity (TP, effective porosity (EP, water saturation (Sw, and hydrocarbon saturation (Sh. Cross-plots of the petrophysical parameters versus depth were illustrated. Five hydrocarbon bearing reservoirs were delineated in well 1, four in well 2. The reservoirs in well 3 do not contain hydrocarbon. The estimated reservoir porosity varies from 10% to 21% while their permeability values range from 20md to 1400md. The porosity and permeability values suggest that reservoirs are good enough to store and also permit free flow of fluid. The volume of shale (0.05% to 0.35% analysis reveals that the reservoirs range from shaly sand to slightly shaly sand to clean sand reservoir. On the basis of petrophysics data, the reservoirs are interpreted a good quality reservoir rocks which has been confirmed with high effective porosity range between 20% and high hydrocarbon saturation exceeding 55% water saturation in well 1 and well 2. Water saturation 3 is nearly 100% although the reservoir properties are good.  

  15. 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. © 2014 Wiley Periodicals, Inc.

  16. Crop improvement projects in Peru

    International Nuclear Information System (INIS)

    Broeshart, H.

    1978-01-01

    Only two percent of the territory of Peru consists of arable land. Sixteen million people depend on the production of about three million hectares of land, which means that on the average only 1800 square metres is available per person. It is clear that Peru is one of the poorest countries of the world as far as available arable land is concerned and consequently it will have to drastically increase its agricultural production per unit area or import large quantities of agricultural products to feed its rapidly growing population. Agricultural research on the efficient use of fertilizers is being carried out by the regional experiment station (CRIA), by the National University of Agriculture, La Molina, Lima, dealing with programmes on maize, potatoes, cereals and forage crops, by national universities in the country and by specialized research institutes for tropical agriculture on sugar-cane, cotton, coffee and tea. Isotope and radiation techniques are a particularly effective means of determining the best cultural practices for the efficient use of fertilizers and water, and the Joint FAO/IAEA Division of Atomic Energy in Food and Agriculture has been involved in the organization of field and greenhouse programmes at experiment stations and universities in Peru since 1963

  17. Hydrological modeling of the Peruvian–Ecuadorian Amazon Basin using GPM-IMERG satellite-based precipitation dataset

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    R. Zubieta

    2017-07-01

    Full Text Available In the last two decades, rainfall estimates provided by the Tropical Rainfall Measurement Mission (TRMM have proven applicable in hydrological studies. The Global Precipitation Measurement (GPM mission, which provides the new generation of rainfall estimates, is now considered a global successor to TRMM. The usefulness of GPM data in hydrological applications, however, has not yet been evaluated over the Andean and Amazonian regions. This study uses GPM data provided by the Integrated Multi-satellite Retrievals (IMERG (product/final run as input to a distributed hydrological model for the Amazon Basin of Peru and Ecuador for a 16-month period (from March 2014 to June 2015 when all datasets are available. TRMM products (TMPA V7 and TMPA RT datasets and a gridded precipitation dataset processed from observed rainfall are used for comparison. The results indicate that precipitation data derived from GPM-IMERG correspond more closely to TMPA V7 than TMPA RT datasets, but both GPM-IMERG and TMPA V7 precipitation data tend to overestimate, compared to observed rainfall (by 11.1 and 15.7 %, respectively. In general, GPM-IMERG, TMPA V7 and TMPA RT correlate with observed rainfall, with a similar number of rain events correctly detected ( ∼  20 %. Statistical analysis of modeled streamflows indicates that GPM-IMERG is as useful as TMPA V7 or TMPA RT datasets in southern regions (Ucayali Basin. GPM-IMERG, TMPA V7 and TMPA RT do not properly simulate streamflows in northern regions (Marañón and Napo basins, probably because of the lack of adequate rainfall estimates in northern Peru and the Ecuadorian Amazon.

  18. Evidence for Cenozoic extensional basin development and tectonic inversion south of the flat-slab segment, southern Central Andes, Chile (33° 36°S.L.)

    Science.gov (United States)

    Charrier, R.; Baeza, O.; Elgueta, S.; Flynn, J. J.; Gans, P.; Kay, S. M.; Muñoz, N.; Wyss, A. R.; Zurita, E.

    2002-04-01

    The mainly volcanic Cenozoic deposits that make up much of the western part of the Principal Cordillera in Central Chile are generally subdivided into two major units: an older Abanico or Coya-Machalí Formation and a younger Farellones Formation. Difficulty in differentiating these units has led to considerable debate. On the basis of the wide distribution, great thickness, and presence of sedimentary intercalations, it has been postulated that these arc volcanics were deposited in an intermontane basin; more recently, it has been proposed that this basin developed under extensional conditions and underwent subsequent tectonic inversion. We present field, geochronologic, geochemical, and thermal maturity data that support the latter interpretation. Collectively, this new information clarifies the stratigraphic, tectonic, and paleogeographic evolution of these deposits. The vast geographic extent of the Abanico Formation and lateral equivalents, which reach from at least 32°30' to 44°S along the Principal Cordillera, its great thickness, and the presence of repeated thick fluvial and lacustrine intercalations all indicate deposition in a large, strongly subsident, and probably north-south oriented basin, developed between middle to late Eocene and Oligocene. The unconformable contact with underlying Mesozoic units observed at several localities indicates that deposition followed a substantial erosional episode during late Cretaceous and/or early Cenozoic time. Basal deposits of the Abanico Formation near Termas del Flaco increase rapidly in thickness to the west. Still further to the west, a thick Abanico section contains, in its upper part, mammal fossils older than those found in the basal deposits near Termas. This evidence indicates a major space of deposition west of this locality, which had been filled before deposition took place at Termas. The east-vergent, high-angle El Fierro thrust fault on the east side of the westward-growing deposits is interpreted

  19. Climate and tectonic evolution of the Descanso-Yauri basin in the northernmost Altiplano: Archetype example of a 'lithospheric drip' basin

    Science.gov (United States)

    Kar, N.; Garzione, C. N.

    2015-12-01

    We present a new multiproxy Miocene-Pliocene paleoelevation record of the northernmost Altiplano plateau reconstructed from pollen, clumped isotope (TΔ47) and δ18Oc of sedimentary carbonates and leaf wax n-alkane δD signatures. The ~18Ma to ~9Ma deposits of our study area, Descanso-Yauri basin in southern Peru show 11 to 16ºC warmer than modern mean annual air temperature, low elevation vegetation pollen assemblage (dominated by Podocarpus), and an average precipitation δ18Omw (VSMOW) value of -8.3±2.0‰ (2σ). The ~5 to 4 Ma deposits in the Descanso-Yauri basin are characterized by herb and shrub vegetation and an average δ18O mw (VSMOW) value of -14.6±3.0‰ (2σ), indicative of an elevation and/or climate similar to modern conditions. Based on the multiproxy paleoclimate record, we interpret that there was a 2±1 km surface uplift between 9 and 5 Ma in the northernmost Altiplano plateau. Deformation history analysis through map scale structural investigation combined with provenance analysis from conglomerate clast composition and paleocurrents show that the thrusts bounding the NE side of the Descanso-Yauri basin were active until ˜9Ma. Deformation waned afterwards, and switched to an extensional deforma