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Sample records for rocks central southern

  1. Preliminary Map of Potentially Karstic Carbonate Rocks in the Central and Southern Appalachian States

    Science.gov (United States)

    Weary, David J.

    2008-01-01

    Karst is a landscape produced by dissolution of rocks and the development of integrated subterranean drainages dominated by the flow of ground water in solutionally enlarged conduits. Karst landscapes typically include cave entrances, sinkholes, blind valleys, losing streams, springs, and large and small-scale solution features on bedrock surfaces. Water-bearing rocks beneath the surface containing solutionally enlarged pores, fractures, or conduits are referred to as karst aquifers. About 40 percent of all ground water extracted in the United States comes from karst aquifers (Karst Waters Institute). Karst means many things to many people. To most cavers and many speleologists, karst means areas containing caves. To engineers, home builders, local governments, and insurance companies, karst is exemplified by the occurrence of sinkholes and subsidence hazard. To hydrologists, well drillers, and environmental consultants, the focus on karst may be more limited to karst aquifers and springs. Precise figures are not available, but ground collapses in karst areas in the United States require hundreds of millions of dollars in repair and mitigation costs each year. Most karst in the United States is formed in either carbonate or evaporite rocks. This map depicts only areas of carbonate rock outcrop, the chief host for karst formation in the eastern United States. The U.S. Geological Survey (USGS), in cooperation with the National Cave and Karst Research Institute (NCKRI), the National Speleological Society (NSS), and various State geological surveys, is working on a new national karst map that will delineate areas of karst and karst-like features nationwide. This product attempts to identify potentially karstic areas of the Appalachian states as defined by the Appalachian Regional Commission (ARC), with the addition of the state of Delaware. This map is labeled preliminary because there is an expectation that it will be revised and updated as part of a new national

  2. Geochemistry and petrogenesis of Late Carboniferous igneous rocks from southern Mongolia: Implications for the post-collisional extension in the southeastern Central Asian Orogenic Belt

    Science.gov (United States)

    Hu, Chuansheng; Li, Wenbo; Huang, Qiuyue; Xu, Cheng; Zhou, Jiaan; Li, Zhihua

    2017-08-01

    Late Carboniferous is a critical period in terms of the tectonic evolution of the Central Asian Orogenic Belt (CAOB). In this study, we report the petrology, geochronology and geochemistry of Late Carboniferous mafic to felsic rocks from southern Mongolia, to better characterize the Late Carboniferous magmatism in the southeastern CAOB. Three types of igneous rocks have been identified, including diabase dykes, porphyritic granites and quartz monzonite dykes. LA-ICP MS zircon U-Pb dating of these rocks shows that the diabase dykes and porphyritic granites were simultaneously emplaced at 306 Ma. The quartz monzonite dykes were subsequently emplaced at 300 Ma. The diabases belong to the high-K calc-alkaline series and show strong enrichment of large ion lithophile elements (LILE; e.g., Rb, Ba and Sr) and depletion in high field strength elements (HFSE; Nb, Ta and Ti), with enriched mantle isotopic signature (εNd(t) = -2.6 to +0.5). They were likely derived from the partial melting of metasomatized sub-continental lithospheric mantle (SCLM) and experienced variable degrees of crustal contamination. The porphyritic granites are characterized by high SiO2 contents, strong negative Eu anomalies with low εNd(t) values of -3.0 to -2.7, suggesting that they were derived from crustal anatexis and experienced strong fractional crystallization. Compared with the porphyritic granites, quartz monzonites display lower SiO2 contents, weaker negative Eu anomalies with higher and more variable εNd(t) values (-0.3 to +4.2). This indicates that the quartz monzonites were probably generated by the mixing of crust- and mantle-derived magmas. The petrographic and geochemical data suggest that all the mafic to felsic rocks in the southern Mongolia formed in a post-collisional extensional setting.

  3. Provenances and tectonic implications of Paleozoic siliciclastic rocks from the Baishuijiang Group of the southern Qinling belt, central China

    Science.gov (United States)

    Wang, Tao; Wang, Zongqi; Ma, Zhenhui; Wang, Dongsheng

    2017-05-01

    The Paleozoic Baishuijiang Group is exposed in the southern Qinling belt and consists of turbidite sediments. The provenances of the Paleozoic sedimentary rocks is constrained by the integration of major and trace elements and detrital zircon U-Pb dating, which can help to understand the connection between the provenance and the Paleozoic tectonic evolution of the Qinling orogenic belt. The sandstones and mudstones have intermediate SiO2/Al2O3 and K2O/Na2O ratios, and high Fe2O3 + MgO contents. In comparison with average upper continental crust, they show strong negative Nb-Ta and Sr anomalies, slight depletion of Zr-Hf and Th, but moderate enrichment of Sc, Ni and Cr. These rocks show LREE enrichment, and pronounced negative Eu anomalies in chondrite-normalized REE patterns, similar to post-Archean shales. The weathering trend of the sandstones and mudstones suggests andesitic and granodioritic provenances. These sediments are geochemically similar to continental island arc sediments, and therefore were probably deposited at an active continental margin. Detrital zircon U-Pb dating of five sandstones from the Baishuijiang Group yielded ages ranging from 407 to 3000 Ma, with six peaks at ca. 425, 710, 780, 930, 1800, and 2500 Ma. The youngest age peak at 425 Ma and two zircon grains with a weighted average age of 414 Ma indicate that the maximum depositional age of the Baishuijiang Group is late Paleozoic. Our new age data thus suggest that these turbidite sediments were mainly derived from the northern Qinling belt and the northern margin of the Yangtze Block. We propose that the Paleozoic sediments were deposited in an ocean basin between the northern Qinling belt and the Yangtze Block. Combined with regional geological evidences, our results indicate that there was a paleo-ocean in the Qinling orogenic belt since Neoproterozoic era. The oceanic crust was continually subducted northward, resulting in multiple accretion events from the early Paleozoic to early

  4. Southern Tunisia, Central Mediterranean

    African Journals Online (AJOL)

    GREGORY

    2010-09-13

    Sep 13, 2010 ... Length-weight relationships (LWR) were estimated for 13 fish species which are of economic relevance in the commercial fisheries of the Gulf of Gabes (southern Tunisia). A total of 2403 fish specimens were sampled with several fishing gears from October 2008 to September 2009. The sample size ranged ...

  5. U Pb dating of plutonic rocks involved in the nappe tectonic in southern Cameroon: consequence for the Pan-African orogenic evolution of the central African fold belt

    Science.gov (United States)

    Toteu, Sadrack Felix; Fouateu, Rose Yongue; Penaye, Joseph; Tchakounte, Jacqueline; Mouangue, Aubin Ciriaque Seme; Van Schmus, William Randall; Deloule, Etienne; Stendal, Henrik

    2006-04-01

    TIMS-ID and SIMS U-Pb dating on zircons from metaplutonic rocks involved in the Pan-African nappe of southern Cameroon allow definition of three groups of subduction-related intrusions: group-I intrusions represented by the Masins metagabbro in the Lomie region yielded 666 ± 26 Ma; group-II intrusions represented by the Mamb metasyenogabbro and the Yaoundé pyriclasite yielded ca. 620 Ma and are broadly coeval with the deposition of the Yaoundé metasediments; group-III intrusions represented by the Elon augen metagranite and the Ngaa Mbappe metamonzodiorite yielded ca. 600 Ma. The onset of the nappe tectonics occurred under high-grade conditions in the range 616 to 610 Ma and continued around 600 Ma with the emplacement of the shallowest nappes. Finally, the construction of southern Cameroon proceeded by a multi-stage evolution characterized by a long-lived development of magmatic arcs associated with rapid opening and closure of sedimentary marginal basins in relation to a northward subduction.

  6. Southern Carpathian rock glaciers: Inventory, distribution and environmental controlling factors

    Science.gov (United States)

    Onaca, Alexandru; Ardelean, Florina; Urdea, Petru; Magori, Brigitte

    2017-09-01

    Rock glaciers are valuable diagnostic landforms indicating permafrost creeping during their genesis and activity. Based on the analysis of high quality air-orthophoto and field work, a first polygon-based inventory of rock glaciers from the Southern Carpathians has been elaborated. In total, 306 rock glaciers were included in the inventory comprising 79 debris and 227 talus rock glaciers. Most of these landforms were classified as relict (258), while only 48, covering 2.81 km2, were considered intact. The size of rock glaciers, considered as a proxy for past environmental conditions, and the relationships with the predictor variables (lithology, aspect, contributing area, geographic coordinates, elevation and slope range) were analysed using bivariate statistics, analysis of variance (ANOVA) and various post hoc tests. The statistical analysis revealed that the rock glaciers occurring in the highest mountain ranges in areas composed of granites and granodiorites are considerably larger than the others, because their duration of activity is greater. Strong dependences between rock glacier size and other topographic attributes (contributing area, aspect and slope range) were also confirmed. The rock glacier distribution in the Southern Carpathians is clearly controlled by topography, lithology and debris availability. The abundance of rock glaciers increases with altitude, but their size decreases slightly. In mountain units where granites and granodiorites predominate (Retezat and Parâng Mountains), the density of rock glaciers and the mean specific area covered by these spectacular landforms are considerably higher than in other areas. The higher continentality effects of the Southern Carpathians enabled the formation of rock glaciers at substantially lower elevations than in the Alps. The mean altitude of intact rock glaciers front, which could be used as a morphological indicator of discontinuous permafrost, is located at 2088 m.

  7. Attempts of whole-rock K/Ar dating of mesozoic volcanic and hypabissal igneous rocks from the Central Subbetic (Southern Spain: A case of differential Argon loss related to very low-grade metamorphism

    Directory of Open Access Journals (Sweden)

    Sanz de Galdeano, C.

    1988-04-01

    Full Text Available 12 samples of basic intrusives within Triassic rocks «ophites» and 11 samples of volcanic and associated intrusives within Jurassic to Early Cretaceous sequences of the Subbetic Zone were subjected to whole-rock K/Ar dating in combination with chemical/petrological analysis. Satisfactory results were obtained only from a number of samples of volcanic rocks, however, analytical ages commonly agree, within about 10 relative percent, with those deduced from stratigraphic location. «Ophite» samples, on the other hand, may reveal considerably lower analytic ages than the volcanics and show much stronger scattering, even among samples collected within a small area. It is argued that the inferred loss of Ar results from very-low-grade alpine metamorphic alteration, which affected the «ophites» more intensely than the higher volcanic rocks. Other post-emplacement chemical changes, such as the degree of secondary oxidation of Fe, are also distintive among the two groups of samples, and are to some extent consistent with the above view in that the alteration environment of the ophites should have produced conditions for more penetrative fluid-rock interactions and homogeneous recrystallization. Overall, the magmatic activity from which the ophitic rocks originated might have started in the Late Triassic and continued in the Lower Jurassic. 80th, the «ophites» and the volcanics are though to be the result of magmatic events Collowing tensional to transtensive crustal movements affecting the external basins of the Betic Cordilleras Crom Late Triassic to Early Cretaceous times.Doce muestras de cuerpos básicos intrusivos en rocas triásicas («ofitas» y 11 muestras de volcanitas y rocas intrusivas asociadas en secuencias jurásico-cretáceas de la zona Subbética han sido objeto de datación radiométrica K/Ar (roca total en combinación con análisis químico-petrográfico. Las edades analíticas obtenidas son 's

  8. Rock glaciers, Central Andes, Argentina, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — Primary rock glaciers are fed by avalanche chutes. At the El Salto rock glacier, surveys have been undertaken in order to determine the creep rate. Between 1981 and...

  9. Petrogenesis of Late Cenozoic basaltic rocks from southern Vietnam

    Science.gov (United States)

    An, A.-Rim; Choi, Sung Hi; Yu, Yongjae; Lee, Der-Chuen

    2017-02-01

    Major and trace element concentrations, and Sr-Nd-Hf-Pb isotopic compositions of Late Cenozoic (4.1 to 13.8 Ma) basaltic rocks from southern Vietnam have been determined to understand the nature of their mantle source. The volcanic rocks are composed of tholeiite basalt, alkaline basanite, trachybasalt, basaltic trachyandesite, and trachyandesite. The alkaline rocks show light rare earth element (LREE) enrichment, with (La/Yb)N = 10.3-29.8. The tholeiite basalts are distinguished by much lower values (8.8-9.5) of (La/Yb)N. On a primitive mantle-normalized trace element distribution diagram, they show oceanic island basalt (OIB)-like large-ion lithophile element enrichment without high field strength element depletion. However, some samples exhibit positive anomalies in K and Pb and negative anomalies in Sm, suggesting K-rich residual amphibole in the source. The samples contain Sr (87Sr/86Sr = 0.703794-0.704672), Nd (ɛNd = + 1.7-5.7), Hf (ɛHf = + 4.0-10.9), and Pb (206Pb/204Pb = 18.23-18.75; 207Pb/204Pb = 15.53-15.59; 208Pb/204Pb = 38.32-38.88) isotopes, plotting among OIBs, with depleted mid-ocean ridge basalt mantle-enriched mantle type 2 (DMM-EM2) characteristics. There are no discernible isotopic differences between tholeiite and the alkaline series, reflecting the same source. The Nd and Hf isotopic compositions are coupled, and plot along the mantle-crust array, ruling out the possibility of lithospheric mantle in the source. Plots of NiO against the Fo numbers of olivines from the basaltic rocks are within the range of Hainan and Hawaiian basalt olivines, implying that hybrid pyroxenite is present in the source. Also note that the estimated primary melt compositions fall within the experimental field defined by partial melting of silica-poor eclogite and peridotite. The effective melting pressure (Pf) and melting temperature (T) of the primary melts are Pf = 29.6-32.8 kbar and T = 1470-1480 °C. We suggest that Vietnamese basaltic rocks may be produced by

  10. Mesozoic and Cenozoic rocks from Malta Escarpment (central Mediterranean)

    Energy Technology Data Exchange (ETDEWEB)

    Scandone, P. (Istituto di Geologia e Paleontologia, Pisa, Italy); Patacca, E.; Radoicic, R.; Ryan, W.B.F.; Cita, M.B.; Rawson, M.; Chezar, H.; Miller, E.; McKenzie, J.; Rossi, S.

    1981-07-01

    Sedimentary rocks of Triassic-Neogene age are present on the Malta Escarpment of the eastern Mediterranean. Upper Triassic dolomitic limestones of shallow-water origin, at depths between 2.5 and 3.5 km, are similar in lithofacies to coeval platform carbonates of the Siracusa (Syracuse) belt of southern Sicily. Jurassic rocks include lower-middle Liassic shallow-water limestones followed by condensed hemipelagic lime deposits indicative of sinking and starving of the former platform. Cretaceous materials are represented by both red marls rich in planktonic faunas and reworkd volcaniclastic breccias including shallow-water skeletal material. Paleogene rocks are both shallow-water limestones with corals, algae, and bivalves, and redeposited calcarenites of lithofacies similar to those from surface and subsurface of the Ragusa zone. Oligocene-lower Miocene rocks from the escarpment are also similar in lithology to the coeval Ragusa deposits. Tortonian is represented by hemipelagic marls indicating open-marine environment. Pervasive dolomitization on lime crusts and on initial-stage fissure fillings with strongly positive isotopic oxygen ratio is thought to be a product of Messinian evaporitic drawdown. Pliocene sediments belong to the Trubi facies and consist of pelagic foraminiferal chalk. An impressive vertical relief existed by Miocene times, as attested by Messinian crusts and veins on or in rocks as old as Late Triassic. Our data do not provide evidence that this morphologic feature necessarily coincides with a continent-ocean transition. The present escarpment was produced by faulting, erosion, and defacement. 14 figures, 1 table.

  11. Analysis of gravity data in Central Valleys, Oaxaca, southern, Mexico

    Science.gov (United States)

    Gonzalez, T.; Ferrusquia, I.

    2015-12-01

    The region known as Central Valleys is located in the state of Oaxaca, southern, Mexico (16.3o- 17.7 o N Lat. and 96 o - 97 o W Long.) In its central portion is settled the capital of the state. There are very few published detailed geological studies.. Geomorphological and geological features, indicates that Central Valleys and surrounding mountains conform a graben structure. Its shape is an inverted Y, centred on Oaxaca City. The study area was covered by a detailed gravity survey with a homogenous distribution of stations. The Bouguer gravity map is dominated by a large gravity low, oriented NW-SE. In order to know the characteristics of anomalies observed gravity, data transformations were used. The use of spectral methods has increased in recent years, especially for the estimation of the depth of the source. Analysis of the gravity data sheds light on the regional depth of the Graben basement and the spatial distribution of the volcanic rocks

  12. Petrology of the Plutonic Rocks of west-central Alaska

    Science.gov (United States)

    Miller, Thomas P.

    1970-01-01

    A series of plutons in west-central Alaska defines the Hogatza plutonic belt which extends for about 200 miles in an east-west direction from the northeastern Seward Peninsula to the Koyukuk River. The plutonic rocks have an aggregate area of about 1,200 square miles and their composition, distribution, and possible petrogenesis are discussed for the first time in this report. Field, petrographic and chemical data supported by K/Ar age dating indicate the plutonic rocks are divisible into two suites differing in age, location, and composition. The western plutons are mid-Cretaceous (~100 m.y.) in age and consist of a heterogeneous assemblage of monzonite, syenite, quartz monzonite. Associated with these granitic rocks is a group of alkaline sub-silicic rocks that forma belt of intrusive complexes extending for a distance of at least 180 miles from west-central Alaska to the Bering Sea. The complex at Granite Mountain shows a rare example of zoning from an alkaline rim to a quartz-bearing core. The occurrence of a similar complex at Cape Dezhnev on the easternmost tip of Siberia suggests the alkaline province may extend into Siberia. The easternmost plutons are Late Cretaceous (180 m.y.) in age and composed primarily of granodiorite and quartz monzonite similar to calc-alkaline plutons found throughout the North America Cordillera. The plutons are epizonal and intrude deformed but unmetamorphosed Lower Cretaceous andesitic volcanics and volcanic graywacke which constitute the highly mobile Yukon-Koyukuk volcanogenic province of west-central Alaska. No older rocks have been found within the confines of this vast tract; the occurrence of a bounding ophiolite sequence has lead to the suggestion that the province was formed by large-scale rifting and is underlain by oceanic crust. The possibility of no juvenile sialic crust over much of the area suggests that the potassium-rich magma now represented by the alkaline rocks originated in the mantle. The distribution of the

  13. Rock Magnetic Record of the Middle Miocene Climatic Transition at ODP Site 747, Southern Ocean

    Science.gov (United States)

    Abrajevitch, A.; Roberts, A. P.; Kodama, K.

    2013-12-01

    ODP Site 747, located on the central Kerguelen Plateau, contains a compete record of the Middle Miocene Climatic Transition (MMCT) - a major cooling event that followed the warm mid-Miocene Climatic Optimum and culminated in an 'icehouse' climate regime. Because of its unusually well preserved and rich foraminiferal assemblages, the MMCT interval at Site 747 has been a focus of several high-resolution paleoclimatic studies that have effectively established this sequence as a reference for the Southern Ocean. Major changes in species abundances across the MMCT are conventionally interpreted to reflect changes in water temperature and salinity. Our XRF and rock magnetic study reveals a good correlation between terrigenous input (likely from local volcanic sources) and the abundances of the dominant planktonic foraminiferal species. Such a correlation suggests that nutrient flux (iron fertilization) played a significant role in controlling microplankton communities during the MMCT at Site 747. Concentration-dependent rock magnetic parameters appear to be a useful proxy for nutrient flux in this pelagic marine environment.

  14. Remagnetization of carbonate rocks in southern Tibet : Perspectives from rock magnetic and petrographic investigations

    NARCIS (Netherlands)

    Huang, Wentao; Lippert, Peter C.; Zhang, Yang; Jackson, Michael J.; Dekkers, Mark J.; Li, Juan; Hu, Xiumian; Zhang, Bo; Guo, Zhaojie; van Hinsbergen, Douwe J.J.

    The latitudinal motion of the Tibetan Himalaya—the northernmost continental unit of the Indian plate—is a key component in testing paleogeographic reconstructions of the Indian plate before the India-Asia collision. Paleomagnetic studies of sedimentary rocks (mostly carbonate rocks) from the Tibetan

  15. A permafrost distribution estimate for the Southern Alps, New Zealand, inferred from topoclimatic conditions at rock glacier sites

    Science.gov (United States)

    Sattler, Katrin; Mackintosh, Andrew; Anderson, Brian; Norton, Kevin; de Róiste, Mairead

    2014-05-01

    The presence of numerous rock glaciers and perennial snow patches indicate the existence of discontinuous alpine permafrost in New Zealand's Southern Alps. However, research on the geographic extent of permafrost in the South Island has been limited. Existing estimates are restricted to single mountain ranges or focus on steep bedrock permafrost. A recent global-scale estimate has not been evaluated by local observations. We present the results of a regional, spatially distributed permafrost estimate for the Southern Alps, focusing on debris-covered slopes. Permafrost distribution modelling was based on the statistical evaluation of 280 active and relict rock glaciers. Logistic regression identified characteristic topoclimatic conditions at the head area of presently active rock glaciers. Statistical relationships between permafrost presence, mean annual air temperature, and potential incoming solar radiation in snow-free months were subsequently used to calculate the spatially distributed probability of permafrost occurrence. The potential permafrost extent was delineated using a probability threshold of ≥ 0.6. Model results suggest that topoclimatic conditions are favourable for permafrost occurrence above ~ 2000 m a.s.l. in the central Southern Alps and above ~ 2150 m a.s.l. in the northern ranges. This gradient in permafrost altitude reflects the warmer climate at lower latitudes. Model results were locally validated by BTS (bottom temperature of snow cover) data derived from two-year continuous ground surface temperature (GST) measurements in the Ben Ohau Range, central Southern Alps. Applicability of BTS measurements for permafrost mapping had not been tested previously in the maritime setting of New Zealand, where common warm spells during winter can result in isothermal snow pack conditions, preventing the inference of late-winter equilibrium temperatures. BTS-indicated permafrost sites were in good agreement with modelled permafrost probabilities at the

  16. The Vaigat Rock Avalanche Laboratory, west-central Greenland

    Science.gov (United States)

    Dunning, S.; Rosser, N. J.; Szczucinski, W.; Norman, E. C.; Benjamin, J.; Strzelecki, M.; Long, A. J.; Drewniak, M.

    2013-12-01

    Rock avalanches have unusually high mobility and pose both an immediate hazard, but also produce far-field impacts associated with dam breach, glacier collapse and where they run-out into water, tsunami. Such secondary hazards can often pose higher risks than the original landslide. The prediction of future threats posed by potential rock avalanches is heavily reliant upon understanding of the physics derived from an interpretation of deposits left by previous events, yet drawing comparisons between multiple events is normally challenging as interactions with complex mountainous terrain makes deposits from each event unique. As such numerical models and the interpretation of the underlying physics which govern landslide mobility is commonly case-specific and poorly suited to extrapolation beyond the single events the model is tuned to. Here we present a high-resolution LiDAR and hyperspectral dataset captured across a unique cluster of large rock avalanche source areas and deposits in the Vaigat straight, west central Greenland. Vaigat offers the unprecedented opportunity to model a sample of > 15 rock avalanches of various age sourced from an 80 km coastal escarpment. At Vaigat many of the key variables (topography, geology, post-glacial history) are held constant across all landslides providing the chance to investigate the variations in dynamics and emplacement style related to variable landslide volume, drop-heights, and thinning/spreading over relatively simple, unrestricted run-out zones both onto land and into water. Our data suggest that this region represents excellent preservation of landslide deposits, and hence is well suited to calibrate numerical models of run out dynamics. We use this data to aid the interpretation of deposit morphology, structure lithology and run-out characteristics in more complex settings. Uniquely, we are also able to calibrate our models using a far-field dataset of well-preserved tsunami run-up deposits, resulting from the 21

  17. Brucellosis in Terekeka County, Central Equatoria State, Southern ...

    African Journals Online (AJOL)

    Objectives: To identify factors associated with Brucellosis in patients attending Terekeka Health Facility, Terekeka County, Central Equatoria State, Southern Sudan and to evaluate the utility of the rapid test kit Euracil®. Design: A facility based case-control study. Setting: Terekeka Health Facility, Terekeka County, Central ...

  18. Contrasting responses of Central Asian rock glaciers to global warming

    OpenAIRE

    Annina Sorg; Andreas Kääb; Andrea Roesch; Christof Bigler; Markus Stoffel

    2015-01-01

    While the responses of Tien Shan glaciers ? and glaciers elsewhere ? to climatic changes are becoming increasingly well understood, this is less the case for permafrost in general and for rock glaciers in particular. We use a novel approach to describe the climate sensitivity of rock glaciers and to reconstruct periods of high and low rock glacier activity in the Tien Shan since 1895. Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photograph...

  19. Driving a Fishery along the Bumpy Ride of Today's Globalisation: The Case of the Australian Southern Rock Lobster Association

    NARCIS (Netherlands)

    Dentoni, D.; Lu, J.; English, F.; McBride, R.

    2012-01-01

    The case of the Australian Southern Rock Lobster Association describes real issues faced by the Market Development Manager of a collective agri-food organization (SRL) representing all the southern rock lobster fishermen in Victoria, South Australia and Tasmania. The case deals with recent

  20. Beach rocks of the central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Wagle, B.G.

    both. The contrasts in the coastal features appear to have resulted from a combination of changes in the sea level, climate, lithology, structure and local tec tunic movement (Wagle 1989). Results and Discussion The beach rocks are exposed..., sufficient shell content and ground water temperature have also favored the for mation of these rocks. Essent;al to beach rock devel- opment is ground water with enough calcium to pro-, vide cement. A limestone hinterland is favorable bUl not critical...

  1. VIRTUAL HERITAGE ARCHIVES: BUILDING A CENTRALIZED AUSTRALIAN ROCK ART ARCHIVE

    Directory of Open Access Journals (Sweden)

    R. A. Haubt

    2013-07-01

    Full Text Available This paper examines use of multi-media in the curation, presentation and promotion of rock art. It discusses the construction of a centralised Australian rock art database and explores new technologies available for looking at rock art. In 2011, Prof. Taçon Chair in Rock Art Research and Director of PERAHU (Place, Evolution and Rock Art Heritage Unit called for a national rock art database raising awareness of the importance of preserving rock art as part of Australia's valuable Indigenous heritage (Taçon, 2011. Australia has over 100,000 rock art sites, important heritage places for Indigenous and non-Indigenous Australians and a testament to over 10,000 years of human activity, including interactions with other peoples and the environment. Many of these sites have not been documented or recorded and are threatened by natural and cultural agents. It is becoming increasingly important to develop conservation models for the protection and preservation of sites. Indigenous cultural heritage is difficult to manage on a local government level due to complex human / time / environment relationships and the importance of intangible cultural heritage (SoE SEWPAC, 2011. Currently no centralised database system exists in Australia to curate, present and promote rock art.

  2. Contrasting responses of Central Asian rock glaciers to global warming

    Science.gov (United States)

    Sorg, Annina; Kääb, Andreas; Roesch, Andrea; Bigler, Christof; Stoffel, Markus

    2015-01-01

    While the responses of Tien Shan glaciers – and glaciers elsewhere – to climatic changes are becoming increasingly well understood, this is less the case for permafrost in general and for rock glaciers in particular. We use a novel approach to describe the climate sensitivity of rock glaciers and to reconstruct periods of high and low rock glacier activity in the Tien Shan since 1895. Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photography from Soviet archives and high-resolution satellite imagery, we present here the world's longest record of rock glacier movements. We also demonstrate that the rock glaciers exhibit synchronous periods of activity at decadal timescales. Despite the complex energy-balance processes on rock glaciers, periods of enhanced activity coincide with warm summers, and the annual mass balance of Tuyuksu glacier fluctuates asynchronously with rock glacier activity. At multi-decadal timescales, however, the investigated rock glaciers exhibit site-specific trends reflecting different stages of inactivation, seemingly in response to the strong increase in air temperature since the 1970s. PMID:25657095

  3. Contrasting responses of Central Asian rock glaciers to global warming

    Science.gov (United States)

    Sorg, Annina; Kääb, Andreas; Roesch, Andrea; Bigler, Christof; Stoffel, Markus

    2015-02-01

    While the responses of Tien Shan glaciers - and glaciers elsewhere - to climatic changes are becoming increasingly well understood, this is less the case for permafrost in general and for rock glaciers in particular. We use a novel approach to describe the climate sensitivity of rock glaciers and to reconstruct periods of high and low rock glacier activity in the Tien Shan since 1895. Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photography from Soviet archives and high-resolution satellite imagery, we present here the world's longest record of rock glacier movements. We also demonstrate that the rock glaciers exhibit synchronous periods of activity at decadal timescales. Despite the complex energy-balance processes on rock glaciers, periods of enhanced activity coincide with warm summers, and the annual mass balance of Tuyuksu glacier fluctuates asynchronously with rock glacier activity. At multi-decadal timescales, however, the investigated rock glaciers exhibit site-specific trends reflecting different stages of inactivation, seemingly in response to the strong increase in air temperature since the 1970s.

  4. Contrasting responses of Central Asian rock glaciers to global warming.

    Science.gov (United States)

    Sorg, Annina; Kääb, Andreas; Roesch, Andrea; Bigler, Christof; Stoffel, Markus

    2015-02-06

    While the responses of Tien Shan glaciers--and glaciers elsewhere--to climatic changes are becoming increasingly well understood, this is less the case for permafrost in general and for rock glaciers in particular. We use a novel approach to describe the climate sensitivity of rock glaciers and to reconstruct periods of high and low rock glacier activity in the Tien Shan since 1895. Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photography from Soviet archives and high-resolution satellite imagery, we present here the world's longest record of rock glacier movements. We also demonstrate that the rock glaciers exhibit synchronous periods of activity at decadal timescales. Despite the complex energy-balance processes on rock glaciers, periods of enhanced activity coincide with warm summers, and the annual mass balance of Tuyuksu glacier fluctuates asynchronously with rock glacier activity. At multi-decadal timescales, however, the investigated rock glaciers exhibit site-specific trends reflecting different stages of inactivation, seemingly in response to the strong increase in air temperature since the 1970s.

  5. Ruffed grouse population dynamics in the central and southern Appalachians

    Science.gov (United States)

    John M. Giuliano Tirpak; C. Allan Miller; Thomas J. Allen; Steve Bittner; David A. Buehler; John W. Edwards; Craig A. Harper; William K. Igo; Gary W. Norman; M. Seamster; Dean F. Stauffer

    2006-01-01

    Ruffed grouse (Bonasa urnbellus; hereafter grouse) populations in the central and southern Appalachians are in decline. However, limited information on the dynamics of these populations prevents the development of effective management strategies to reverse these trends. We used radiotelemetry data collected on grouse to parameterize 6 models of...

  6. Coniferous forest habitat types of central and southern Utah

    Science.gov (United States)

    Andrew P. Youngblood; Ronald L. Mauk

    1985-01-01

    A land-classification system based upon potential natural vegetation is presented for the coniferous forests of central and southern Utah. It is based on reconnaissance sampling of about 720 stands. A hierarchical taxonomic classification of forest sites was developed using the habitat type concept. Seven climax series, 37 habitat types, and six additional phases of...

  7. Remote sensing of rock glacier activity in the Spanish Peaks region of southern Colorado

    Science.gov (United States)

    Miles, C.; Savage, A.; Gomez, F. G.

    2016-12-01

    Owing to the significance of rock glaciers for water resources and indicators of climate change, there is a need to improve the capability to monitor changes in rock glacier activity (and, hence, the state of the ground ice) for alpine settings. Remote sensing tools potentially provide means of conducting regional studies. This study focuses on the Spanish Peaks region of southern Colorado where glacial- and talus-derived rock glaciers are found predominantly on slopes of late Cenozoic felsic intrusions. Mapping of rock glaciers and other rock-debris landforms is based on high resolution optical imagery. Talus-derived rock glaciers are typically found at lower altitudes than those derived from rock-buried glaciers and moraines. We utilize Interferometric Synthetic Aperture Radar (InSAR) to identify active rock glaciers (and their temporal kinematic variations). InSAR analyses includes recent data from the Sentinel-1 mission (2015 - present), as well as older archived data spanning through the 1990s. For selected rock glaciers, field verification is also provided by repeat GPS surveys and ground-based radar interferometry spanning 2014 - 2016. Seasonal changes in flow rate are observed, as well as annual variations that may correspond with differing amounts of winter precipitation. This study also explores the utility of thermal remote sensing as a possible tool to identify landforms with significant ground ice. Analysis of thermal emittance data from Landsat and ASTER imagery suggests that active rock glaciers and relatively ice-free landforms (as determined from InSAR) might be distinguishable. This is further tested using 1-dimensional thermal modeling. Compared with InSAR data archives, the potential utility of thermal remote sensing data may allow analysis of longer data archives for a better view of changes periglacial environmental state.

  8. From Central Asia to South Africa: In Search of Inspiration in Rock Art Studies

    Directory of Open Access Journals (Sweden)

    Rozwadowski Andrzej

    2017-06-01

    Full Text Available The paper describes the story of discovering South African rock art as an inspiration for research in completely different part of the globe, namely in Central Asia and Siberia. It refers to those aspect of African research which proved to importantly develop the understanding of rock art in Asia. Several aspects are addressed. First, it points to importance of rethinking of relationship between art, myth and ethnography, which in South Africa additionally resulted in reconsidering the ontology of rock images and the very idea of reading of rock art. From the latter viewpoint particularly inspiring appeared the idea of three-dimensionality of rock art ‘text’. The second issue of South African ‘origin,’ which notably inspired research all over the world, concerns a new theorizing of shamanism. The paper then discusses how and to what extent this new theory add to the research on the rock art in Siberia and Central Asia.

  9. Contrasting responses of Central Asian rock glaciers to global warming

    National Research Council Canada - National Science Library

    Sorg, Annina; Kääb, Andreas; Roesch, Andrea; Bigler, Christof; Stoffel, Markus

    2015-01-01

    .... Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photography from Soviet archives and high-resolution satellite imagery, we present here the world's...

  10. The timing of the tectono-metamorphic evolution at the Neoproterozoic-Phanerozoic boundary in central southern Madagascar

    DEFF Research Database (Denmark)

    Giese, Jörg; Berger, Alfons; Schreurs, Guido

    2011-01-01

    In central southern Madagascar the crystalline basement is composed of mid-crustal rocks which have experienced polycyclic deformation and metamorphism coupled with repeated granitoid magmatism at the Neoproterozoic–Phanerozoic boundary. Based on the integration of in situ U–Th–Pb dating of monaz......In central southern Madagascar the crystalline basement is composed of mid-crustal rocks which have experienced polycyclic deformation and metamorphism coupled with repeated granitoid magmatism at the Neoproterozoic–Phanerozoic boundary. Based on the integration of in situ U–Th–Pb dating...... of monazite and structural relationships,twodistinct phases of major ductile deformation, the Andreaba and Ihosy phases can be distinguished in central southern Madagascar. Both these deformation phases occur between ~550 and 520 Ma. Coeval with, and outlasting deformation, granitic plutons and dykes were...... that the whole crustal section remained in a mid-crustal position. Metamorphic overprinting related to M2 is spatially limited and is heterogeneously distributed in central southern Madagascar. Newly developed M2 mineral assemblages are preferentially found in areas featuring Ihosy phase vertical foliation...

  11. Maturity of carboniferous source rocks in Central Onshore Netherlands. the impact of the Permian thermal anomaly

    NARCIS (Netherlands)

    Abdul Fattah, R.; Verweij, J.M.

    2014-01-01

    Pre-Westphalian layers are considered as potential source rocks in the Netherlands. However, there is little amount of information available on their maturity. 3D basin modelling is carried out on Central Onshore Netherlands to investigate the maturity of the deep Carboniferous source rocks. A

  12. 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.

  13. Early human settlements in the southern Qinling Mountains, central China

    Science.gov (United States)

    Sun, Xuefeng; Lu, Huayu; Wang, Shejiang; Yi, Liang; Li, Yongxiang; Bahain, Jean Jacques; Voinchet, Pierre; Hu, Xuzhi; Zeng, Lin; Zhang, Wenchao; Zhuo, Haixin

    2017-05-01

    China is a key area of early human settlement in East Asia, with numerous Paleolithic localities indicating an early Pleistocene presence of hominins in northern and southern China. Considerable research has been devoted to determining possible migration routes for hominins linking the two areas. In this paper, we report the discovery of several loess-covered Paleolithic sites in the Hanzhong and Ankang Basins along the Hanjiang River in the southern piedmont of the Qinling Mountains (QLM) in central China. A chronology is developed for these sections using a combination of detailed optically stimulated luminescence dating, magnetostratigraphic analyses, and pedostratigraphic correlation with the well-dated loess-paleosol sequence of the central Chinese Loess Plateau. The results indicate that the age of the oldest lithic assemblage at the Longgangsi locality 3 Paleolithic site in Hanzhong Basin is ∼1.20 Ma, thus making this locality as one of the oldest sites in central China. Our work also indicates that hominins occupied the Hanjiang valley at several times: ∼1.2, 0.9, ∼0.6, and ∼0.1 Ma. We propose that the Hanjiang River Valley was a probable hominin routeway through the QLM because many sites corresponding to these different phases were also discovered to the north of the QLM. Future study on the Hanjiang River Valley is important for verifying the hypothesis of an early human migration route between southern and northern China.

  14. Neogene folding and faulting in southern Monterey Bay, Central California, USA

    Science.gov (United States)

    Gardner-Taggart, J. M.; Greene, H. Gary; Ledbetter, M.T.

    1993-01-01

    The goal of this study was to determine the Neogene structural history of southern Monterey Bay by mapping and correlating the shallow tectonic structures with previously identified deeper occurring structures. Side scan sonographs and Uniboom seismic reflection profiles collected in the region suggest that deformation associated with both compressional and transcurrent movement is occurring. Strike-slip movement between the North American and Pacific plates started as subduction ceased 21 Ma, creating the San Andreas fault system. Clockwise rotation of the Pacific plate occurred between 3.4 and 3.9 Ma causing orthogonal convergence between the two plates. This plate rotation is responsible for compressional Neogene structures along the central California coast. Structures exhibit transpressional tectonic characteristics such as thrust faulting, reverse faulting and asymmetrical folding. Folding and faulting are confined to middle Miocene and younger strata. Shallow Mesozoic granitic basement rocks either crop out or lie near the surface in most of the region and form a possible de??collement along which the Miocene Monterey Formation has decoupled and been folded. Over 50% of the shallow faults strike normal (NE-SW) to the previously identified faults. Wrench fault tectonics complicated by compression, gradual uplift of the basement rocks, and a change in plate convergence direction are responsible for the observed structures in southern Monterey Bay. ?? 1993.

  15. The Cambrian-Ordovician rocks of Sonora, Mexico, and southern Arizona, southwestern margin of North America (Laurentia): chapter 35

    Science.gov (United States)

    Page, William R.; Harris, Alta C.; Repetski, John E.; Derby, James R.; Fritz, R.D.; Longacre, S.A.; Morgan, W.A.; Sternbach, C.A.

    2013-01-01

    Cambrian and Ordovician shelf, platform, and basin rocks are present in Sonora, Mexico, and southern Arizona and were deposited on the southwestern continental margin of North America (Laurentia). Cambrian and Ordovician rocks in Sonora, Mexico, are mostly exposed in scattered outcrops in the northern half of the state. Their discontinuous nature results from extensive Quaternary and Tertiary surficial cover, from Tertiary and Mesozoic granitic batholiths in western Sonora, and from widespread Tertiary volcanic deposits in the Sierra Madre Occidental in eastern Sonora. Cambrian and Ordovician shelf rocks were deposited as part of the the southern miogeocline on the southwestern continental margin of North America.

  16. Karst subsidence in South-Central Apulia, Southern Italy.

    Directory of Open Access Journals (Sweden)

    Delle Rose Marco

    2002-01-01

    Full Text Available Subsidence in the karst of Apulia (Southern Italy, one of the classical karst areas of Italy, is described in this paper. The carbonate rocks that make up the geological structure of the Apulia region are affected by subsidence, which is of different type and intensity depending upon geological, topographical, and hydrogeological conditions. In particular, we discriminate between inland subsidence and coastal subsidence. Inland subsidence is generally restricted to the presence of individual cavities, either empty or partly or totally filled with deposits produced by dissolution of soluble rocks underground. Locally, such subsidence can cause severe effects on anthropogenic structures above. The coastal plains of Apulia, particularly the southernmost part (Salento Peninsula, show interesting karst subsidence. Here the main feature is the development of compound sinks extending for several thousands of square metres, or the formation of individual, mostly circular, dolines along the coastline. Occurrence of one or the other of the above features seems to depend upon topographical conditions, and also upon their relationship with sea level oscillations.

  17. Stratigraphy, geochemistry and tectonic significance of the Oligocene magmatic rocks of western Oaxaca, southern Mexico

    Science.gov (United States)

    Martiny, B.; Martinez-Serrano, R. G.; Moran-Zenteno, D. J.; MacIas-Romo, C.; Ayuso, R.A.

    2000-01-01

    In Western Oaxaca, Tertiary magmatic activity is represented by extensive plutons along the continental margin and volcanic sequences in the inland region. K-Ar age determinations reported previously and in the present work indicate that these rocks correspond to a relatively broad arc in this region that was active mainly during the Oligocene (~ 35 to ~ 25 Ma). In the northern sector of western Oaxaca (Huajuapan-Monte Verde-Yanhuitlan), the volcanic suite comprises principally basaltic andesite to andesitic lavas, overlying minor silicic to intermediate volcaniclastic rocks (epiclastic deposits, ash fall tuffs, ignimbrites) that were deposited in the lacustrine-fluvial environment. The southern sector of the volcanic zone includes the Tlaxiaco-Laguna de Guadalupe region and consists of intermediate to silicic pyroclastic and epiclastic deposits, with silicic ash fall tuffs and ignimbrites. In both sectors, numerous andesitic to dacitic hypabyssal intrusions (stocks and dikes) were emplaced at different levels of the sequence. The granitoids of the coastal plutonic belt are generally more differentiated than the volcanic rocks that predominate in the northern sector and vary in composition from granite to granodiorite. The studied rocks show large-ion lithophile element (LILE) enrichment (K, Rb, Ba, Th) relative to high-field-strength (HFS) elements (Nb, Ti, Zr) that is characteristic of subduction-related magmatic rocks. On chondrite-normalized rare earth element diagrams, these samples display light rare earth element enrichment (LREE) and a flat pattern for the heavy rare earth elements (HREE). In spite of the contrasting degree of differentiation between the coastal plutons and inland volcanic rocks, there is a relatively small variation in the isotopic composition of these two suites. Initial 87Sr/86Sr ratios obtained and reported previously for Tertiary plutonic rocks of western Oaxaca range from 0.7042 to 0.7054 and ??Nd values, from -3.0 to +2.4, and for

  18. Petrology of ocean floor rocks from Central Indian Ocean basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; Karisiddaiah, S.M.

    • .,.• • . 10 11 •o 2 3 4 5Cms _!~~~~!~~'=::'--I~._._. _ ~ ;;~:III~il;;~' • ...."':.{.r·· Fig. 7-Holohyaline texture. Fig. 8--TWlOncd and zoned plllgioclase (crossed nicols). Fig. 9-Vesicle with a dark globule (?j, Fig. IG--Crushed rock with quartz, feldspar... in nature and undcrw'?nt changes in its composition due to varying pressure-temperature conditions. This has resulted in basalts which are do minantly constituted of plagioclase and olivine \\-\\·ith less vesicles. The variations in the anorthite content...

  19. Major structural controls on the distribution of pre-Tertiary rocks, Nevada Test Site vicinity, southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Cole, J.C.

    1998-10-23

    The lateral and vertical distributions of Proterozoic and Paleozoic sedimentary rocks in southern Nevada are the combined products of original stratigraphic relationships and post-depositional faults and folds. This map compilation shows the distribution of the pre-Tertiary rocks in the region including and surrounding the Nevada Test Site. It is based on considerable new evidence from detailed geologic mapping, biostratigraphic control, sedimentological analysis, and a review of regional map relationships. Proterozoic and Paleozoic rocks of the region record paleogeographic transitions between continental shelf depositional environments on the east and deeper-water slope-facies depositional environments on the west. Middle Devonian and Mississippian sequences, in particular, show strong lateral facies variations caused by contemporaneous changes in the western margin of North America during the Antler orogeny. Sections of rock that were originally deposited in widely separated facies localities presently lie in close proximity. These spatial relationships chiefly result from major east- and southeast-directed thrusts that deformed the region in Permian or later time. Somewhat younger contractional structures are identified within two irregular zones that traverse the region. These folds and thrusts typically verge toward the west and northwest and overprint the relatively simple pattern of the older contractional terranes. Local structural complications are significant near these younger structures due to the opposing vergence and due to irregularities in the previously folded and faulted crustal section. Structural and stratigraphic discontinuities are identified on opposing sides of two north-trending fault zones in the central part of the compilation region north of Yucca Flat. The origin and significance of these zones are enigmatic because they are largely covered b Tertiary and younger deposits. These faults most likely results from significant lateral

  20. Geochemistry of the alkaline volcanicsubvolcanic rocks of the Fernando de Noronha Archipelago, southern Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Rosana Peporine Lopes

    Full Text Available The Fernando de Noronha Archipelago presents, on its main island, a centrally-located stratigraphic unit, the Remédios Formation (age around 8 - 12 Ma constituted by basal pyroclastic rocks intruded by dikes, plugs and domes of varied igneous rocks, capped by flows and pyroclastics of mafic to ultramafic rocks of the Quixaba Formation (age around 1 - 3 Ma, which is limited from the underlying unit by an extensive irregular erosion surface. A predominant sodic Remédios series (basanites, tephrites, tephriphonolites, essexite, phonolites can be separated from a moderately potassic Remédios sequence (alkali basalts, trachyandesites, trachytes, both alkaline series showing mostly continuous geochemical trends in variation diagrams for major as well as trace elements, indicating evolution by crystal fractionation (mainly, separation of mafic minerals, including apatites and titanites. There are textural and mineralogical evidences pointing to hybrid origin of some intermediate rocks (e.g., resorbed pyroxene phenocrysts in basaltic trachyandesites, and in some lamprophyres. The primitive Quixaba rocks are mostly melanephelinites and basanites, primitive undersaturated sodic types. Geology (erosion surface, stratigraphy (two distinct units separated by a large time interval, petrography (varied Remédios Formation, more uniform Quixaba unit and geochemistry indicate that the islands represent the activity of a protracted volcanic episode, fueled by intermittent melting of an enriched mantle, not related to asthenospheric plume activity.

  1. Evidence of Quaternary rock avalanches in the central Apennines: new data and interpretation of the huge clastic deposit of the L'Aquila basin (central Apennines, Italy)

    Science.gov (United States)

    Esposito, Carlo; Scarascia Mugnozza, Gabriele; Tallini, Marco; Della Seta, Marta

    2014-05-01

    Active extensional tectonics and widespread seismicity affect the axial zone of the central Apennines (Italy) and led to the formation of several plio-quaternary intermontane basins, whose morpho-evolution was controlled by the coupling of tectonic and climatic inputs. Common features of the Apennines intermontane basins as well as their general morpho-evolution are known. Nonetheless, the complex interaction among regional uplift, local fault displacements and morpho-climatic factors caused differences in the denudational processes of the single intermontane basins. Such a dynamic response left precious records in the landscape, which in some cases testify for the occurrence of huge, catastrophic rock slope failures. Several Quaternary rock avalanches have been identified in central Apennines, which are often associated with Deep Seated Gravitational Slope Deformation (DSGSD) and thus strictly related to the geological-structural setting as well as to the Quaternary morpho-structural evolution of the mountain chain. The L'Aquila basin is one of the intermontane tectonic depression aligned along the Middle Aterno River Valley and was the scene of strong historical earthquakes, among which the last destructive event occurred on April 6, 2009 (Mw 6.3). We present here the evidence that the huge clastic deposit on which the city of L'Aquila was built up is the body of a rock avalanche detached from the southern slope of the Gran Sasso Range. The clastic deposit elongates for 13 km to the SW, from the Assergi Plain to L'Aquila and is characterized by typical morphological features such as hummocky topography, compressional ridges and run-up on the opposite slope. Sedimentological characters of the deposit and grain size analyses on the matrix let us confirm the genetic interpretation, while borehole data and significant cross sections allowed us reconstructing the 3D shape and volume of the clastic body. Finally, morphometric analyses of the Gran Sasso Range southern

  2. Rock glacier analyses in the Tyrolean Central Alps based on airborne lidar-data

    Science.gov (United States)

    Girstmair, Anna; Mitterer-Hoinkes, Susanna; Bollmann, Erik; Krainer, Karl; Sailer, Rudolf; Stötter, Johann

    2013-04-01

    Airborne LIDAR-datasets offer a high potential for the monitoring of surface changes within high mountain environments. Based on an analysis of rock glaciers with airborne LIDAR-datasets a rock glacier activity index is developed. The results are then compared to the classified rock glacier activities from the Tyrolean rock glacier inventory. LIDAR-data from 2006 and 2010 are used to generate bi-temporal, high-resolution DTMs, for more than 400 rock glaciers in the Tyrolean Central Alps (Austria). The differential DTMs are used to identify basic processes on rock glacier surfaces including vertical and horizontal displacement rates. In order to calculate the vertical displacement rates the DTMs from 2006 are subtracted from 2010 DTMs, whereas the velocities are calculated by image matching. Based on the DTMs the mean and standard deviation of the surface elevation changes and the surface velocities are calculated for each rock glacier. The accuracy of the results of the surface elevation change calculations is improved by applying a simple stable area approach. This approach allows to correct the systematic error between the bi-temporal DTMs, yielding a higher accuracy for the vertical displacement rates. By combining the normalized mean and standard deviation of the surface elevation changes and velocities, a rock glacier activity index is developed. The activity index ranges from values between zero and one indicating low and high activity rates for each rock glacier. A clear trend between the activity index and the rock glacier inventory is found. Most of the active classified rock glaciers show a high activity index with values exceeding 0.4 and most of the fossil classified rock glaciers show a low activity index with values around zero. Discrepancies between the two methods, the developed rock glacier activity index and the prior manual rock glacier classification, will be discussed. The activity index is in good agreement with the standard classification of

  3. The variability and controls of rock strength along rocky coasts of central Spitsbergen, High Arctic

    Science.gov (United States)

    Strzelecki, Mateusz Czesław

    2017-09-01

    This paper presents the results of the Schmidt Hammer Rock Tests (SHRTs) across a range of rocky coastal landforms. Northern Billefjorden (central Spitsbergen), represents typical High Arctic microtidal fjord environment. Sheltered location and prolonged sea-ice conditions limit wave action. Coastal cliffs, shore platforms and skerries are developed in various rock types including limestone, sandstone, anhydrite/gypsum, dolomite and metamorphic outcrops. SHRT demonstrated a broad variety of relationships between rock strength and distance from shoreline, presence of sediment cover, distribution of snow patches and icefoot, and accumulations of seaweed and driftwood. In general, rock cliff surfaces were the most resistant in their lower and middle zones, that are thermally insulated by thick winter snowdrifts. More exposed cliff tops were fractured and weathered. The differences in rock strength observed along the shore platforms were highly dependent on thickness of sediment cover and shoreline configuration promoting stronger rock surfaces in areas exposed to the longest wave fetch and washed from gravel deposits. Rock strength of skerry islands is influenced by tidal action controlling the duration of tide inundation and movement of sea-ice scratching boulder surfaces. The results presented in this paper emphasize the richness of rock coast geomorphology and processes operating in High Arctic settings.

  4. Sinkhole susceptibility in carbonate rocks of the Apulian karst (southern Italy)

    Science.gov (United States)

    Di Santo, Antonio; Fazio, Nunzio L.; Fiore, Antonio; Lollino, Piernicola; Luisi, Michele; Miccoli, Maria N.; Pagliarulo, Rosa; Parise, Mario; Perrotti, Michele; Pisano, Luca; Spalluto, Luigi; Vennari, Carmela; Vessia, Giovanna

    2016-04-01

    Apulia region, the foreland of the southern Italian Apennines, is made up of a 6-7 km-thick succession of Mesozoic shallow-water limestones and dolostones, locally covered by thin and discontinuous Tertiary and Quaternary carbonate and clastic deposits. Due to their long subaerial exposure, the Mesozoic carbonate bedrock recorded the development in the subsurface of a dense network of karst cavities, mostly controlled by tectonic discontinuities. As a result, a strong susceptibility to natural sinkholes has to be recorded in Apulia. In addition, the possibility of occurrence of other problems related to the high number of man-made cavities has to be added in the region. A great variety of different typologies of artificial cavities (mostly excavated in the Plio-Pleistocene soft calcarenites) is actually present, including underground quarries, worship sites, oil mills, civilian settlements, etc. Overall, 2200 natural and 1200 artificial cavities, respectively, have been so far surveyed in Apulia. Following the urban development in the last century in Apulia, many of these cavities lie nowadays below densely populated neighborhoods, roads or communication routes. These conditions are at the origin of the main geomorphological hazard for the human society in Apulia, which requires a careful evaluation, aimed at protecting and safeguarding the human life, and at providing the necessary information for a correct land use planning and management. The importance of the sinkhole hazard is further testified by the worrying increase in the number of events during the last 5-6 years. In response to these situations, joint research activities were started by the Institute of Research for Hydrological Protection of the National Research Council (CNR-IRPI) and the Basin Authority of Apulia, aimed at several goals, that include (but are not limited to) the collection of information on natural and anthropogenic sinkholes in Apulia, the implementation of numerical analyses for

  5. Uranium and thorium enrichment in rocks from the base of DSDP hole 465A, Hess Rise, central North Pacific

    Energy Technology Data Exchange (ETDEWEB)

    Hein, J.R.; Koski, R.A.; Morgenson, L.A. (Geological Survey, Menlo Park, CA (USA))

    1982-07-01

    Uranium and thorium are concentrated in Cretaceous limestone, chert, ash, basalt, and other rock types at Deep Sea Drilling Project Site 465 located on the southern Hess Rise in the central North Pacific. U concentrations, up to 194 ppm on a carbonate-free basis, are among the highest recorded for any deep-sea deposits. U was initially derived from seawater and concentrated by absorption on terrigenous (humic) organic matter in limestone in a shallow marine environment. U and Th were probably concentrated further by low-temperature hydrothermal fluids emanating from the basaltic basement. Mainly montmorillonite, an alteration product of basalt and ash, and organic matter in sedimentary rocks acted as hosts for U and Th. The unique combination of sediments rich in humic organic matter, abundant smectite in altered ash and basalt, and warm hydrothermal solutions provided the necessary conditions for migration and concentration of U and Th. To better understand the conditions limiting the migrating and concentration of U and Th, other rocks deposited during the ocean-wide Cretaceous anoxic events should be analyzed for these elements.

  6. Kyanite-eclogite to amphibolite fades evolution of hydrous mafic and pelitic rocks, Adula nappe, Central Alps

    Science.gov (United States)

    Heinrich, Christoph A.

    1982-11-01

    In the southern Adula nappe (Central Alps), two stages of regional metamorphism have affected mafic and pelitic rocks. Earlier eclogite facies with a regional zonation from glaucophane eclogites to kyanite-hornblende eclogites was followed by a Tertiary overprint which varied from greenschist to high-grade amphibolite facies. Despite a common metamorphic history, contrasting equilibration conditions are often recorded by high-pressure mafic eclogite and adjacent predominantly lower-pressure pelite assemblages. This pressure contrast may be explained by different overprinting rates of the two bulk compositions during unloading. The rates are controlled by a mechanism in which dehydrating metapelites provide the H2O required for simultaneous overprinting of enclosed mafic eclogites by hydration. Quantitative mass balance modelling based on corona textures is used to show that overprinting of meta pelites during unloading involved dehydration reactions. The relatively rapid rate of dehydration reactions led to nearly complete reequilibration of metapelites to amphibolite facies assemblages. After the formation during high-pressure metamorphism of mafic eclogites, later lower-pressure reequilibration by hydration to amphibolites was slow, and therefore incomplete, because it depended on large scale transport of H2O from adjacent, dehydrating metapelites. The facies contrast observed between rocks of different bulk composition is thus a consequence of the general tendency of metamorphic rocks to retain the most dehydrated assemblage as the final recorded state.

  7. Laramide structure of the central Sangre de Cristo Mountains and adjacent Raton Basin, southern Colorado

    Science.gov (United States)

    Lindsey, D.A.

    1998-01-01

    Laramide structure of the central Sangre de Cristo Mountains (Culebra Range) is interpreted as a system of west-dipping, basement-involved thrusts and reverse faults. The Culebra thrust is the dominant structure in the central part of the range; it dips 30 -55?? west and brings Precambrian metamorphic base-ment rocks over unmetamorphosed Paleozoic rocks. East of the Culebra thrust, thrusts and reverse faults break the basement and overlying cover rocks into north-trending fault blocks; these boundary faults probably dip 40-60?? westward. The orientation of fault slickensides indicates oblique (northeast) slip on the Culebra thrust and dip-slip (ranging from eastward to northward) movement on adjacent faults. In sedimentary cover rocks, east-vergent anticlines overlie and merge with thrusts and reverse faults; these anticlines are interpreted as fault-propagation folds. Minor east-dipping thrusts and reverse faults (backthrusts) occur in both the hanging walls and footwalls of thrusts. The easternmost faults and folds of the Culebra Range form a continuous structural boundary between the Laramide Sangre de Cristo highland and the Raton Basin. Boundary structures consist of west-dipping frontal thrusts flanked on the basinward side by poorly exposed, east-dipping backthrusts. The backthrusts are interpreted to overlie structural wedges that have been emplaced above blind thrusts in the basin margin. West-dipping frontal thrusts and blind thrusts are interpreted to involve basement, but backthrusts are rooted in basin-margin cover rocks. At shallow structural levels where erosion has not exposed a frontal thrust, the structural boundary of the basin is represented by an anticline or monocline. Based on both regional and local stratigraphic evidence, Laramide deformation in the Culebra Range and accompanying synorogenic sedimentation in the western Raton Basin probably took place from latest Cretaceous through early Eocene time. The earliest evidence of uplift and

  8. Sulfide mineralization in ultramafic rocks of the Faryab ophiolite complex, southern Kerman

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Rajabzadeh

    2015-10-01

    Full Text Available Introduction Worldwide, Ni-Cu and PGE magmatic sulfide deposits are confined to the lower parts of stratiform mafic and ultramafic complexes. However, ophiolite mafic and ultramafic complexes have been rarely explored for sulfide deposits despite the fact that they have been extensively explored and exploited for chromite. Sulfide saturation during magmatic evolution is necessary for sulfide mineralization, in which sulfide melts scavenge chalcophile metals from the parent magma and concentrate them in specific lithological zones. The lack of exploration for sulfides in this environment suggests that sulfide saturation is rarely attained in ophiolite-related magmas. Some ophiolites, however, contain sulfide deposits, such as at Acoje in Philippines, and Cliffs in Shetland, U.K. (Evans, 2000; Naldrett, 2004. The Faryab ophiolite complex in southern Kerman Province, the most important mining area for chromite deposits in Iran, is located in the southwest part of the Makran Zone. Evidence of sulfide mineralization has been reported there by some authors (e.g. Rajabzadeh and Moosavinasab, 2013. This paper discusses the genesis of sulfides in the Faryab ophiolite using mineral chemistry of the major mineral phases in different rocks of the ophiolite column in order to determine the possible lithological location of sulfide deposits. Materials and methods Seventy three rock samples from cumulate units were collected from surficial occurrences and drill core. The samples were studied using conventional microscopic methods and the mineralogy confirmed by x-ray diffraction. Electron microprobe analysis was carried out on different mineral phases in order to determine the chemistry of the minerals used in the interpretation of magma evolution in the Faryab ophiolite. Lithologically, the Faryab ophiolite complex is divided into two major parts: the northern part includes magmatic rocks and the southern part is comprised of rocks residual after partial

  9. Late Neoproterozoic basement rocks of Meatiq area, Central Eastern Desert, Egypt: Petrography and remote sensing characterizations

    Science.gov (United States)

    Hassan, Safaa M.; El kazzaz, Yahiya A.; Taha, Maysa M. N.; Mohammad, Abdullah T.

    2017-07-01

    Meatiq dome is one of the mysteries of the basement rocks in Central Eastern Desert (CED) of Egypt. Its mode of formation, and tectonic evolution are still controversial and not fully understood. Satellite remote sensing is a powerful tool for geologic applications, especially in inaccessible regions of the Earth's surface. In this study, three proposed Landsat-8 band ratios (6/2, 6/7, (6/4*4/3)), (6/7, 6/4, 4/2), and (7/5, 7/6, 5/3) are successfully used for detailed geological mapping of the different lithological rock units exposed in Meatiq dome area in the CED. Landsat-8 Principal component (PC) images is also used for refinement the boundaries between the widely-exposed rock units in the study area. Fourteen spectral bands of Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) data are successfully used to emphasize the distribution of some rock forming minerals (i.e. muscovite, quartz, ferrous oxides, ferrous silicates and hydroxyl-bearing minerals) in the lithological rock units of Meatiq dome area. ASTER muscovite index (B7/B6) and quartz index (B14/B12), ferrous iron index (B5/B3), ferrous silicates index (B5/B4), mafic index (B12/B13) and hydroxyl-bearing minerals index ((B7/B6)*(B4/B6)) discriminate muscovite bearing rocks, Granitoids, and other felsic rocks, amphibolite and other mafic rocks. The proposed image processing methods effectively discriminates between four granitic varieties existed in Meatiq area. They are namely; Abu Ziran, Ariki, Fawakhir and Atalla Plutons. This study reveals that the applied data of ASTER and Landsat-8 enhanced images produced a modified geological map with well emphasized rock units which are verified with field observations, and petrographic study.

  10. Paleomagnetism of Permian and Triassic rock, central Chilean Andes

    Science.gov (United States)

    Forsythe, Randall D.; Kent, Dennis V.; Mpodozis, Constantino; Davidson, John

    The first paleomagnetic data from Permian and Triassic formations west of the Andean divide are presented. Four formations of Permian or Triassic age in the central Chilean Andes have been investigated: two are located in the coastal ranges, and two are in the main cordillera. Of the formations in the main cordillera (Pastos Blancos and Matahuaico formations), only the Pastos Blancos Formation has yielded characteristic directions. While a fold test is absent, magnetizations are most likely secondary and yield pre-tilt corrected concordant inclinations, but yield declinations discordant 30° clockwise in comparison to the South American apparent polar wander path. Both formations from the coastal ranges (Cifuncho and Pichidangui formations) yielded stable directions. Postfolding magnetizations in the Cifuncho Formation also show declinations discordant 30° clockwise and concordant inclinations. The Pichidangui Formation has two stable components: one of postfolding age is concordant to apparent polar wander path data, and one of probable prefolding (Late Triassic) age is concordant in declination, but discordant in inclination. Further work is needed to better define the prefolding magnetizations in the Pichidangui Formation, but at present these preliminary results are the first paleomagnetic signs of displaced terranes along the Pacific margin of Chile. If correct, the results suggest that the Pichidangui Formation was some 15° of latitude farther south during the Late Triassic and had likely moved northward to its present latitudinal position with respect to cratonic South America by Middle to Late Jurassic.

  11. Tectonic control of erosion in the southern Central Andes

    Science.gov (United States)

    Val, Pedro; Venerdini, Agostina L.; Ouimet, William; Alvarado, Patricia; Hoke, Gregory D.

    2018-01-01

    Landscape evolution modeling and global compilations of exhumation data indicate that a wetter climate, mainly through orographic rainfall, can govern the spatial distribution of erosion rates and crustal strain across an orogenic wedge. However, detecting this link is not straightforward since these relationships can be modulated by tectonic forcing and/or obscured by heavy-tailed frequencies of catchment discharge. This study combines new and published along-strike average rates of catchment erosion constrained by 10Be and river-gauge data in the Central Andes between 28°S and 36°S. These data reveal a nearly identical latitudinal pattern in erosion rates on both sides of the range, reaching a maximum of 0.27 mm/a near 34°S. Collectively, data on topographic and fluvial relief, variability of rainfall and discharge, and crustal seismicity suggest that the along-strike pattern of erosion rates in the southern Central Andes is largely independent of climate, but closely relates to the N-S distribution of shallow crustal seismicity and diachronous surface uplift. The consistently high erosion rates on either side of the orogen near 34°S imply that climate plays a secondary role in the mass flux through an orogenic wedge where the perturbation to base level is similar on both sides.

  12. AMT and gravity across praTertiary rock complex of Kebumen, Central Java, Indonesia

    Science.gov (United States)

    Laesanpura, Agus; Dahrin, Darharta; Sugianto, Asep

    2017-07-01

    Kebumen area is located in central Java Province, Indonesia, where outcrop of Pretertiary rock of old accretion wedge presence. However, the subsurface of the area, limestone, igneous rock, and Conglomeratic-clay of Karangsambung Formation, is poorly understood in subsurface. The current survey of gravity and AMT data is executing to delineate this boundary. The gravity profile and three point AMT is measure for reconnaissance study. The field observations for rock formations are also scrutinized, but the soil is prohibiting to seen more deep in detail. The general result of interpretation and modeling, show reaching depth of one and half kilo meter, the gravity data cover the mayor rock, but the AMT is more significance in better delineating the boundary. Hence the lithology could be distinguished for mélange rock (1000 Ohm.m) and Karangsambung Formation of clay-conglomerate (80 Ohm.m), but also diabase of volcanic-plutonic rock (4000 Ohm.m). The preliminary result shows two mayor results, for limestone and Diabase. Limestone is spread-out on this area, probably the olistolith, and its extensions is more pronounce in the sounding point than the surface observations only. The mysterious of diabase, is more possible as sill product rather than vertical dike.

  13. Rock-colonizing plants: abundance of the endemic cactus Mammillaria fraileana related to rock type in the southern Sonoran Desert

    Science.gov (United States)

    Blanca R. Lopez; Yoav Bashan; Macario Bacilio; Gustavo. De la Cruz-Aguero

    2009-01-01

    Establishment, colonization, and permanence of plants affect biogenic and physical processes leading to development of soil. Rockiness, temperature, and humidity are accepted explanations to the influence and the presence of rock-dwelling plants, but the relationship between mineral and chemical composition of rocks with plant abundance is unknown in some regions. This...

  14. An overview on source rocks and the petroleum system of the central Upper Rhine Graben

    Science.gov (United States)

    Böcker, Johannes; Littke, Ralf; Forster, Astrid

    2017-03-01

    activation energies. These sediments are considered as most important source rocks of numerous high wax oils (oil family B) in addition to the coaly source rocks from the (Lower) Pechelbronn-Schichten (Late Eocene). Migration pathways are significantly influenced by the early graben evolution. A major erosion period occurred during the latest Cretaceous. The uplift center was located in the northern URG area, resulting in SSE dipping Mesozoic strata in the central URG. During Middle Eocene times a second uplift center in the Eifel area resulted in SW-NE-directed shore lines in the central URG and contemporaneous south-southeastern depocenters during marine transgression from the south. This structural setting resulted in a major NNW-NW-directed and topography-driven migration pattern for expelled Liassic oil in the fractured Mesozoic subcrop below sealing Dogger α clays and basal Tertiary marls.

  15. Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in east- and south-central Alaska

    Science.gov (United States)

    Dusel-Bacon, Cynthia; Csejtey, Bela; Foster, Helen L.; Doyle, Elizabeth O.; Nokleberg, Warren J.; Plafker, George

    1993-01-01

    Most of the exposed bedrock in east- and south-central Alaska has been regionally metamorphosed and deformed during Mesozoic and early Cenozoic time. All the regionally metamorphosed rocks are assigned to metamorphic-facies units on the basis of their temperature and pressure conditions and metamorphic age. North of the McKinley and Denali faults, the crystalline rocks of the Yukon- Tanana upland and central Alaska Range compose a sequence of dynamothermally metamorphosed Paleozoic and older(?) metasedimentary rocks and metamorphosed products of a Devonian and Mississippian continental-margin magmatic arc. This sequence was extensively intruded by postmetamorphic mid-Cretaceous and younger granitoids. Many metamorphic-unit boundaries in the Yukon-Tanana upland are low-angle faults that juxtapose units of differing metamorphic grade, which indicates that metamorphism predated final emplacement of the fault-bounded units. In some places, the relation of metamorphic grade across a fault is best explained by contractional faulting; in other places, it is suggestive of extensional faulting.Near the United States-Canadian border in the central Yukon- Tanana upland, metamorphism, plutonism, and thrusting occurred during a latest Triassic and Early Jurassic event that presumably resulted from the accretion of a terrane that had affinities to the Stikinia terrane onto the continental margin of North America. Elsewhere in the Yukon-Tanana upland, metamorphic rocks give predominantly late Early Cretaceous isotopic ages. These ages are interpreted to date either the timing of a subsequent Early Cretaceous episode of crustal thickening and metamorphism or, assuming that these other areas were also originally heated during the latest Triassic to Early Jurassic and remained buried, the timing of their uplift and cooling. This uplift and cooling may have resulted from extension.South of the McKinley and Denali faults and north of the Border Ranges fault system, medium

  16. Rock partridge (Alectoris graeca graeca population density and trends in central Greece

    Directory of Open Access Journals (Sweden)

    Bontzorlos, V. A.

    2012-01-01

    Full Text Available The rock partridge is an emblematic species of the Greek avifauna and one of the most important game species in the country. The present study, which combined long term in–situ counts with distance sampling methodology in central Greece, indicated that the species’ population in Greece is the highest within its European distribution, in contrast to all prior considerations. Inter–annual trends suggested a stable rock partridge population both within hunting areas and wildlife refuges, whereas during summer, the species presented significantly higher densities in altitudes of more than 1,000 m, most probably due to the effect of predation at lower zones. The similarity of population structure between wildlife refuges and hunting zones along with the stable population trends demonstrate that rock partridge harvest in the country is sustainable.

  17. Biomarker characteristics of source rock and oil seepage correlation in Central Java

    Science.gov (United States)

    Praptisih

    2018-02-01

    The presence of oil seepage in Central Java indicates that there is an effective petroleum system. The problem is where the oil was derived from. Biomarker characteristic is used to provide information on source rock organic matter input, depositional environment and correlation between source rock and oil seepage. The method used for this study is GC and GCMS analyses of the rock extract and oil seepage. The biomarker characteristic suggests that oil seepage in Banjarnegara is derived from the Totogan Formation, while that in Bayat is derived from the Wungkal Formation. Oil seepage in Cipluk area is deposited in the estuarine environment. Therefore, it cannot be correlated with the Kerek Formation. Oil seepage in Kedungjati and Bantal area is not derived from the Kerek and Pelang Formation.

  18. Quantifying rock uplift rates using channel steepness and cosmogenic nuclide–determined erosion rates: Examples from northern and southern Italy

    Science.gov (United States)

    Cyr, Andrew J.; Granger, Darryl E.; Olivetti, Valerio; Molin, Paola

    2010-01-01

    Rock uplift rates can be difficult to measure over 103–105 yr time scales. If, however, a landscape approaches steady state, where hillslope erosion and rock uplift rates are steady and locally similar, then it should be possible to quantify rock uplift rates from hillslope erosion rates. Here, we test this prediction by comparing channel steepness index values and 10Be catchment-averaged erosion rates to well-constrained rock uplift rates in two landscapes in Italy. The first field area is the Romagna Apennines, northern Italy, where rock uplift rates are relatively uniform, between 0.2 and 0.5 mm/yr (regional mean 0.40 ± 0.15 [SE] mm/yr), and have been steady since 0.9 Ma. The second area is the region around northeastern Sicily and the southernmost Italian peninsula, where rock uplift rates are higher and exhibit a strong spatial gradient, from ∼0.7 to ∼1.6 mm/yr (regional mean 1.09 ± 0.13 [SE] mm/yr). In both regions, channel steepness indices and 10Be erosion rates vary directly with rock uplift rates. Although there is considerable variability in erosion rates, regionally averaged rates in both the northern (0.46 ± 0.04 [SE] mm/yr) and southern (1.21 ± 0.24 [SE] mm/yr) areas accurately measure rock uplift rates. Although channel steepness indices do not quantify rock uplift rates, they are useful for (1) identifying regional patterns of rock uplift, (2) identifying areas where uplift rates might be expected to be uniform, and (3) informing 10Be sampling strategies. This study demonstrates that, together, channel steepness and hillslope erosion rates can provide a powerful tool for determining rock uplift rates.

  19. Pattani central mosque in Southern Thailand as sanctuary from violence

    Directory of Open Access Journals (Sweden)

    Ridwan Ridwan

    2014-12-01

    Full Text Available This article describes the real quality of  Pattani Central Mosque to depict another picture of mosques in southern Thailand that has been alleged as an arena for the spreading of Islamic radical ideas and the recruiting of young people into ‘martyrs’ against the Thai Government. It is not doubted, the 2004 Kru-ze Mosque incident reflects the failure of places of worship as a‘sanctuary from violence’. Consequently, there are questions about the kind of practices taking place in Islamic teaching, mosque management, and the views held by mosque stakeholders (Imam, the preachers, and congregation toward good governance, human rights and the anticipation of radicalism given the current situation in Pattani. In sum,  Pattani Central Mosque instead seems to be composed of a fairly equal mixture of moderate and more conservative believers rather than those with radical and extreme tendencies.   Artikel ini mendeskripsikan kualitas yang nyata dari Masjid Raya Pattani untuk mengilustrasikan gambaran lain tentang masjid-masjid di Thailand Selatan yang disinyalir sebagai arena penyebaran ide-ide Islam radikal dan rekruitmen orang–orang muda sebagai “martir” melawan Pemerintah Thailand. Tidak terbantahkan, insiden Masjid Kru-ze tahun 2004 merefleksikan kegagalan tempat-tempat ibadah sebagai ‘sanctuary from violence’. Akibatnya, terdapat sejumlah pertanyaan mengenai jenis-jenis praktik pengajaran, manajemen masjid dan pandangan dari para pengelola/takmir masjid (Imam, juru dakwah, and jemaah terhadap pemerintahan yang baik, hak asasi manusia dan antisipasi atas radikalisme di Pattani dewasa ini. Sebagai kesimpulan, Masjid Raya Pattani tampaknya lebih terbentuk oleh gabungan para pengikut yang moderat dan lebih konservatif dibandingkan mereka yang memiliki tendensi-tendensi radikal dan ekstrem.

  20. Reconsidering the glacier to rock glacier transformation problem: New insights from the central Andes of Chile

    Science.gov (United States)

    Monnier, Sébastien; Kinnard, Christophe

    2015-06-01

    The glacier to rock glacier transformation problem is revisited from a previously unseen angle. A striking case in the Juncal Massif (located in the upper Aconcagua Valley, Chilean central Andes) is documented. There, the Presenteseracae debris-covered glacier has advanced several tens of metres and has developed a rock glacier morphology in its lower part over the last 60 years. The conditions for a theoretically valid glacier to rock glacier transformation are discussed and tested. Permafrost probability in the area of the studied feature is highlighted by regional-scale spatial modelling together with on-site shallow ground temperature records. Two different methods are used to estimate the mean surface temperature during the summer of 2014, and the sub-debris ice ablation rates are calculated as ranging between 0.05 and 0.19 cm d- 1, i.e., 0.04 and 0.17 m over the summer. These low ablation rates are consistent with the development of a coherent surface morphology over the last 60 years. Furthermore, the rates of rock wall retreat required for covering the former glacier at Presenteseracae lie within the common 0.1-2 mm y- 1 range, assuming an average debris thickness and a range of debris-covering time intervals. The integration of the geomorphological observations with the numerical results confirms that the studied debris-covered glacier is evolving into a rock glacier.

  1. Classification of debris-covered glaciers and rock glaciers in the Andes of central Chile

    Science.gov (United States)

    Janke, Jason R.; Bellisario, Antonio C.; Ferrando, Francisco A.

    2015-07-01

    In the Dry Andes of Chile (17 to 35° S), debris-covered glaciers and rock glaciers are differentiated from true glaciers based on the percentage of surface debris cover, thickness of surface debris, and ice content. Internal ice is preserved by an insulating cover of thick debris, which acts as a storage reservoir to release water during the summer and early fall. These landforms are more numerous than glaciers in the central Andes; however, the existing legislation only recognizes uncovered or semicovered glaciers as a water resource. Glaciers, debris-covered glaciers, and rock glaciers are being altered or removed by mining operations to extract valuable minerals from the mountains. In addition, agricultural expansion and population growth in this region have placed additional demands on water resources. In a warmer climate, as glaciers recede and seasonal water availability becomes condensed over the course of a snowmelt season, rock glaciers and debris-covered glaciers contribute a larger component of base flow to rivers and streams. As a result, identifying and locating these features to implement sustainable regional planning for water resources is important. The objective of this study is to develop a classification system to identify debris-covered glaciers and rock glaciers based on the interpretation of satellite imagery and aerial photographs. The classification system is linked to field observations and measurements of ice content. Debris-covered glaciers have three subclasses: surface coverage of semi (class 1) and fully covered (class 2) glaciers differentiates the first two forms, whereas debris thickness is critical for class 3 when glaciers become buried with more than 3 m of surface debris. Based on field observations, the amount of ice decreases from more than 85%, to 65-85%, to 45-65% for semi, fully, and buried debris-covered glaciers, respectively. Rock glaciers are characterized by three stages. Class 4 rock glaciers have pronounced

  2. 77 FR 43586 - Southern Star Central Gas Pipeline, Inc.; Notice of Intent To Prepare an Environmental Assessment...

    Science.gov (United States)

    2012-07-25

    ... Energy Regulatory Commission Southern Star Central Gas Pipeline, Inc.; Notice of Intent To Prepare an... Project involving abandonment of facilities by Southern Star Central Gas Pipeline, Inc. (Southern Star) in... comment on their areas of concern. Southern Star provided landowners with a fact sheet prepared by the...

  3. Early Cretaceous bimodal volcanic rocks in the southern Lhasa terrane, south Tibet: Age, petrogenesis and tectonic implications

    Science.gov (United States)

    Wang, Chao; Ding, Lin; Liu, Zhi-Chao; Zhang, Li-Yun; Yue, Ya-Hui

    2017-01-01

    Limited geochronological and geochemical data from Early Cretaceous igneous rocks of the Gangdese Belt have resulted in a dispute regarding the subduction history of Neo-Tethyan Ocean. To approach this issue, we performed detailed in-situ zircon U-Pb and Hf isotopic, whole-rock elemental and Sr-Nd isotopic analyses on Late Mesozoic volcanic rocks exposed in the Liqiongda area, southern Lhasa terrane. These volcanic rocks are calc-alkaline series, dominated by basalts, basaltic andesites, and subordinate rhyolites, with a bimodal suite. The LA-ICPMS zircon U-Pb dating results of the basaltic andesites and rhyolites indicate that these volcanic rocks erupted during the Early Cretaceous (137-130 Ma). The basaltic rocks are high-alumina (average > 17 wt.%), enriched in large ion lithophile elements (LILEs) and light rare earth elements (LREEs), and depleted in high field strength elements (HFSEs), showing subduction-related characteristics. They display highly positive zircon εHf(t) values (+ 10.0 to + 16.3) and whole-rock εNd(t) values (+ 5.38 to + 7.47). The silicic suite is characterized by low Al2O3 (oceanic lithosphere was flat-lying beneath the Lhasa terrane during the Early Cretaceous.

  4. Fluoride in weathered rock aquifers of southern India: Managed Aquifer Recharge for mitigation.

    Science.gov (United States)

    Brindha, K; Jagadeshan, G; Kalpana, L; Elango, L

    2016-05-01

    Climatic condition, geology, and geochemical processes in an area play a major role on groundwater quality. Impact of these on the fluoride content of groundwater was studied in three regions-part of Nalgonda district in Telangana, Pambar River basin, and Vaniyar River basin in Tamil Nadu, southern India, which experience semi-arid climate and are predominantly made of Precambrian rocks. High concentration of fluoride in groundwater above 4 mg/l was recorded. Human exposure dose for fluoride through groundwater was higher in Nalgonda than the other areas. With evaporation and rainfall being one of the major contributors for high fluoride apart from the weathering of fluoride rich minerals from rocks, the effect of increase in groundwater level on fluoride concentration was studied. This study reveals that groundwater in shallow environment of all three regions shows dilution effect due to rainfall recharge. Suitable managed aquifer recharge (MAR) methods can be adopted to dilute the fluoride rich groundwater in such regions which is explained with two case studies. However, in deep groundwater, increase in fluoride concentration with increase in groundwater level due to leaching of fluoride rich salts from the unsaturated zone was observed. Occurrence of fluoride above 1.5 mg/l was more in areas with deeper groundwater environment. Hence, practicing MAR in these regions will increase the fluoride content in groundwater and so physical or chemical treatment has to be adopted. This study brought out the fact that MAR cannot be practiced in all regions for dilution of ions in groundwater and that it is essential to analyze the fluctuation in groundwater level and the fluoride content before suggesting it as a suitable solution. Also, this study emphasizes that long-term monitoring of these factors is an important criterion for choosing the recharge areas.

  5. Petrographic features of Middle-Late Triassic volcanic rocks of the Transdanubian Range and their comparison to contemporaneous volcanic rocks of the Southern Alps

    Science.gov (United States)

    Farics, Éva; Józsa, Sándor; Haas, János

    2017-04-01

    During the early stage of the Alpine plate tectonic cycle, the Transdanubian Range Unit was located close to the area of the Southern Alps; they were situated at the western margin of the Neotethys. Ocean began opening in the Middle Triassic. Our aim is to present and evaluate the petrographic characteristics of the Middle to Late Triassic volcanic rocks of the Transdanubian Range formed in an extensional regime of the ocean margin and compare them to coeval volcanic formations of the Southern Alps formed in similar geodynamic settings. Andesite (porphyric pilotaxitic texture, with plagioclase and hypersthene, subordinately augite and biotite phenocrysts) is the dominant volcanic rock type in the NE part of the Transdanubian Range (Eastern Bakony - Balatonfő and Buda Hills, which occur as dikes (Buda Hills) and lava flows (Szár Hill). Other volcanic rocks occur only as pebble populations in Eocene basal conglomerates in Buda Hills or Middle-Late Triassic volcanoclastites in the Eastern Bakony and Zsámbék basin. We defined the following rock types: amafitic andesite/microdiorite (consist of two populations of oriented plagioclase and only small abundant glassy groundmass); microdiorite (microophitic texture with large hypersthene, which has plagioclase inclusions in it); trachyte or latite (more primary K-feldspar and less plagioclase phenocrysts with microphenocrysts of augite and biotite); basalt (vesicular texture with pseudomorph after plagioclase, pyroxene and olivine phenocrysts); microdolerite (intergranular texture with pseudomorph after xenomorphic mafic minerals and plagioclase); aplite (microholocrystalline and micropoikilite texture with well-crystallized groundmass; quartz, K-feldspar and biotite crystals); rhyolite (dark and light flow banding and has poorly-developed micropoikilite texture with quartz, K-feldspar and biotite crystals); rhyolite tuff (ignimbrit texture with plagioclase, K-feldspar and biotite as well as lithic fragments - andesite

  6. Pliocene onset of widespread normal faulting in the southern Puna Plateau, southern central Andes, NW Argentina

    Science.gov (United States)

    Montero Lopez, M. C.; Hongn, F. D.; Marrett, R.; Seggiaro, R.; Strecker, M. R.

    2009-12-01

    Normal faults are often observed in many compressional Cenozoic mountain belts and paleotectonic settings and have been associated with a late-stage development in orogen evolution. Often, such normal faults are found in high-elevation sectors in the orogen interior and may form graben, closely spaced arrays or they are kinematically linked with strike-slip faults. In contrast, at lower elevations and in the adjacent foreland regions coeval shortening may be sustained. This situation typifies the active tectonics of the southern central Andes of NW Argentina characterized by the Puna Plateau (22° to 27° S lat), the world’s second largest orogenic plateau with an average elevation of 3.7 km and the adjacent Andean foreland. The Puna contains neotectonic landforms that host widespread active normal faults, closely associated with mafic centres. In contrast, the shortening continued in the foreland. The onset of the extensional kinematic in the Puna has been inferred to be Quaternary in age as many mafic volcanic manifestations were generated during the ultimate 2 Ma. However, our new structural observations and Ar/Ar dating of volcanic deposits and dykes suggests that widespread extension in the Puna started much earlier. We are able to show that the southern margin of the Puna is characterized by extensional structures at different length scales, including extensional fractures, sometimes hosting dykes, as well as normal fault arrays that cut volcanic edifices and flows, visible on satellite imagery. Fault kinematic analysis and an assessment of dyke and fracture orientations documents that the region at about 27°S lat is affected by N-S extension. This must be a regional phenomenon as similar observations can be made in areas farther north as well. Our geochronology work on lava flows and dykes in this region suggests that an extensional regime may have been in existence by 7-6 Ma and extensional processes were well underway by 4 Ma. The often observed

  7. Agonistic behaviour in juvenile southern rock lobster, Jasus edwardsii (Decapoda, Palinuridae: implications for developing aquaculture

    Directory of Open Access Journals (Sweden)

    Chris Carter

    2014-11-01

    Full Text Available The Southern rock lobster, Jasus edwardsii, is a temperate species of spiny lobster with established well managed fisheries in Australia and New Zealand. It has also been under consideration as a species with aquaculture potential. Agonistic behaviour has important consequences under aquaculture conditions that encompass direct effects, such as damage or death of protagonists, and indirect effects on growth that relate to resource access, principally food and refuge. This study aimed to identify and characterize behaviours and to make a preliminary investigation of their occurrence under tank culture. Juvenile Jasus edwardsii were examined in a flow-through seawater system using a remote video camera system. Twenty-nine behaviours were divided into three sub-groups: aggressive (11, avoidance (6 and others (12. Aggressive behaviours included attacks, pushing, lifting, clasping and carrying an opponent. Avoidance behaviours included moving away in a backwards-, forwards- or side-stepping motion as well as with more vigorous tail flips. These behaviours were components of twelve behavioural groups that described contact, attack and displacement between individuals. Activity was crepuscular with two clear peaks, one in the morning and the other in the evening. The occurrence of behavioural groups was not different between the morning and evening. The frequency of aggressive behaviours was not affected by changes made to stocking density or access to food. The implications of agonistic behaviours are discussed further in relation to developing aquaculture.

  8. Agonistic behaviour in juvenile southern rock lobster, Jasusedwardsii (Decapoda, Palinuridae): implications for developing aquaculture.

    Science.gov (United States)

    Carter, Chris G; Westbury, Heath; Crear, Bradley; Simon, Cedric; Thomas, Craig

    2014-01-01

    The Southern rock lobster, Jasusedwardsii, is a temperate species of spiny lobster with established well managed fisheries in Australia and New Zealand. It has also been under consideration as a species with aquaculture potential. Agonistic behaviour has important consequences under aquaculture conditions that encompass direct effects, such as damage or death of protagonists, and indirect effects on growth that relate to resource access, principally food and refuge. This study aimed to identify and characterize behaviours and to make a preliminary investigation of their occurrence under tank culture. Juvenile Jasusedwardsii were examined in a flow-through seawater system using a remote video camera system. Twenty-nine behaviours were divided into three sub-groups: aggressive (11), avoidance (6) and others (12). Aggressive behaviours included attacks, pushing, lifting, clasping and carrying an opponent. Avoidance behaviours included moving away in a backwards-, forwards- or side-stepping motion as well as with more vigorous tail flips. These behaviours were components of twelve behavioural groups that described contact, attack and displacement between individuals. Activity was crepuscular with two clear peaks, one in the morning and the other in the evening. The occurrence of behavioural groups was not different between the morning and evening. The frequency of aggressive behaviours was not affected by changes made to stocking density or access to food. The implications of agonistic behaviours are discussed further in relation to developing aquaculture.

  9. Threatened plant species of the Nevada Test Site, Ash Meadows, central-southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Beatley, J.C.

    1977-04-01

    This report is a companion one to Endangered Plant Species of the Nevada Test Site, Ash Meadows, and Central-Southern Nevada (COO-2307-11) and deals with the threatened plant species of the same area. The species are those cited in the Federal Register, July 1, 1975, and include certain ones listed as occurring only in California or Arizona, but which occur also in central-southern Nevada. As with the earlier report, the purpose of this one is to record in detail the location of the past plant collections which constitute the sole or principal basis for defining the species' distributions and frequency of occurrence in southern Nye County, Nevada, and to recommend the area of the critical habitat where this is appropriate. Many of the species occur also in southern California, and for these the central-southern Nevada records are presented for consideration of the overall status of the species throughout its range.

  10. Pluri-decadal evolution of glacier--rock glacier transitional landforms in the central Andes of Chile

    National Research Council Canada - National Science Library

    Monnier, Sébastien; Kinnard, Christophe

    2017-01-01

    Three glacier–rock glacier transitional landforms in the central Andes of Chile are investigated over the last decades in order to highlight and question the significance of their landscape and flow dynamics. Historical (1955–2000...

  11. The Central Alborz Permian basaltic magmatism: an evidence of southern passive continental margin of Paleo- Tethys

    Directory of Open Access Journals (Sweden)

    Morteza Delavari

    2017-03-01

    Full Text Available The study area is located in the Central Alborz (northeast of Baladeh. The Permianmagmatism in this area occurs as a basaltic unit between Ruteh-Nessen Formation.Petrographically, the rocks are plagioclase phyric and geochemically, display alkalinesodic nature. Chondrite- normalized rare earth element (REE patterns are extremely LREE- enriched similar to those of oceanic island basalts (OIB with (La/SmN,(Sm/YbN and (La/YbN in the ranges of 1.95- 4.62, 4.23- 5.45 and 8.30- 20.52,respectively. Furthermore, primitive mantle normalized multi element diagramsrepresent OIB characteristics. Modeling based on trace element values and the contentof some major elements reveal low degree partial melting (< 10% of a deep (~110 kmgarnet-bearing mantle source. In addition, variation of some trace element ratios such asNb/Rb, K/La, La/Nb, Ba/Nb, Th/Nb and K/Nb suggests a HIMU mantle origin. As thesamples geochemically show intra-plate tectonomagmatic setting without subductionzone signatures. Thus, during the Permian (and earlier times, Alborz has been as apassive continental margin in the southern border of Paleo-Tethys and its magmatism was more probably affected by extensional tectonism or mantle plume activity related toearlier stages of Neo-Tethys ocean development.

  12. Rock Magnetic Properties of a Late Pleistocene Paleosol From Central Mexico

    Science.gov (United States)

    Rivas, J.; Ortega, B.; Solleiro, E.; Sedov, S.

    2005-05-01

    Rock-magnetic characteristics of a volcaniclastic-paleosol sequence from Tlaxcala, central Mexico, are analyzed in order to test the hypothesis of neo-formation of magnetic minerals as result of enhanced pedogenesis in A and B soil horizons, in comparison of the less affected or pedoganically unaltered parent material. Our study was carried out in a Chromic luvisol pedocomplex thought to have been formed during the last interglacial. The results show that, even if pedogenic fine grained magnetic minerals are present in the Bt horizons, these are destroyed in upper horizons, where pedogenesis has been more intense. Horizons A and E present the lowest magnetic susceptibility, however they also present the highest concentration of high coercivity hematite/goethite phases. In order to decode the paleoclimatic signal of this paleosol, rock-magnetism analysis in different pedogenetic materials as the soil itself, and cutans, cracks-filling material and humus found in soils, is in progress.

  13. Correlation between occurrence of manganese nodules and rocks in a part of the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; Sharma, R.

    -138 127 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands Correlation Between Occurrence of Manganese Nodules and Rocks in a Part of the Central Indian Ocean Basin S.D. IYER and R. SHARMA National Institute of Oceanography..., Dona Paula, Goa 403 004 (India) (Received June 23, 1989; revision accepted October 2, 1989) Abstract Iyer, S.D. and Sharma, R., 1990. Correlation between occurrence of manganese nodules and rocks in a part of the Central Indian Ocean Basin. Mar...

  14. Southern pine beetles in central hardwood forests: frequency, spatial extent, and changes to forest structure

    Science.gov (United States)

    John Nowak; Kier Klepzig; D R Coyle; William Carothers; Kamal J K Gandhi

    2015-01-01

    EXCERPT FROM: Natural Disturbances and Historic Range Variation 2015. The southern pine beetle (SPB) is a major disturbance in pine forests throughout the range of southern yellow pines, and is a significant influence on forests throughout several Central Hardwood Region (CHR) ecoregions...

  15. Geochemistry and tectonomagatic setting of Tertiary volcanic rocks of the Kangan area, northeast of Sarbisheh, southern Khorasan

    Directory of Open Access Journals (Sweden)

    Mahshid Malekian Dastjerdi

    2017-02-01

    Full Text Available Introduction The study area is located 12km away from the north east of Sarbisheh at the eastern border of the Lut block (Karimpour et al., 2011; Richards et al., 2012. The magmatic activity in the Lut blockhas begun in the middle Jurassic (165-162 Ma and reached its peak in the Tertiary age (Jung et al., 1983; Karimpour et al., 2011. Volcanic and subvolcanic rocks in the Tertiary age cover over half of the Lut block with up to 2000 m thickness and they were formed due to subduction prior to the collision of the Arabian and Asian plates (Jung et al., 1983; Karimpour et al., 2011. In the Kangan area, the basaltic lavas cropped out beyond the above intermediate to acid volcanic rocks. In this area, bentonite and perlite deposits have an economic importance. The main purpose of this paper is to present a better understanding of the tectono-magmatic settings of volcanic rocks in the northeast of Sarbisheh, east of Iran based on their geochemical characteristics. Materials and methods Fifteen samples were analyzed for major elements by inductively coupled plasma (ICP technologies and trace elements by using inductively coupled plasma mass spectrometry (ICP-MS, following a lithium metaborate/tetraborate fusion and nitric acid total digestion, at the Acme laboratories, Vancouver, Canada. Results The Kangan area is located at the northeast of Sarbishe, Southern Khorasan and the eastern border of the Lut block. In this area, basaltic lavas have cropped out above intermediate to acid lavas such as andesite, dacite, rhyolite (sometimes perlitic .The main minerals in the basalt are plagioclase, olivine and pyroxene, in andesite contain plagioclase, pyroxene, biotite and amphibole and in acid rocks include plagioclase, quartz, sanidine, biotite and amphibole. Intermediate to acid rocks have medium to high-K calc-alkaline nature and basalt is alkaline. Enrichment in LREE relative to HREE (Ce/Yb= 21.14-28.7, high ratio of Zr/Y(4.79- 10.81, enrichment in LILE

  16. Review of potential host rocks for radioactive waste disposal in the southeast United States-Southern Piedmont subregion

    Energy Technology Data Exchange (ETDEWEB)

    1980-10-01

    A literature study was conducted on the geology of the Southern Piedmont province in the states of Maryland, Virginia, North Carolina, South Carolina, and Georgia. The purpose was to identify geologic areas potentially suitable for containment of a repository for the long-term isolation of solidified radioactive waste. The crystalline rocks of the Southern Piedmont province range in age from Precambrian to Paleozoic, and are predominantly slates, phyllites, argillites, schists, metavolcanics, gneisses, gabbros, and granites. These rock units were classified as either favorable, potentially favorable, or unfavorable as potential study areas based on an evaluation of the geologic, hydrologic, and geotechnical characteristics. No socio-economic factors were considered. Rocks subjected to multiple periods of deformation and metamorphism, or described as highly fractured, or of limited areal extent were generally ranked as unfavorable. Potentially favorable rocks are primarily the high-grade metamorphic gneisses and granites. Sixteen areas were classified as being favorable for additional study. These areas are primarily large igneous granite plutons as follows: the Petersburg granite in Virginia; the Rolesville-Castallia, Churchland, and Landis plutons in North Carolina; the Liberty Hill, Winnsboro, and Ogden plutons in South Carolina; and the Siloam, Elberton, and six unnamed granite plutons in Georgia.

  17. Factor analysis of rock, soil and water geochemical data from Salem magnesite mines and surrounding area, Salem, southern India

    Science.gov (United States)

    Satyanarayanan, M.; Eswaramoorthi, S.; Subramanian, S.; Periakali, P.

    2017-09-01

    Geochemical analytical data of 15 representative rock samples, 34 soil samples and 55 groundwater samples collected from Salem magnesite mines and surrounding area in Salem, southern India, were subjected to R-mode factor analysis. A maximum of three factors account for 93.8 % variance in rock data, six factors for 84 % variance in soil data, five factors for 71.2 % in groundwater data during summer and six factors for 73.7 % during winter. Total dissolved solids are predominantly contributed by Mg, Na, Cl and SO4 ions in both seasons and are derived from the country rock and mining waste by dissolution of minerals like magnesite, gypsum, halite. The results also show that groundwater is enriched in considerable amount of minor and trace elements (Fe, Mn, Ni, Cr and Co). Nickel, chromium and cobalt in groundwater and soil are derived from leaching of huge mine dumps deposited by selective magnesite mining activity. The factor analysis on trivalent, hexavalent and total Cr in groundwater indicates that most of the Cr in summer is trivalent and in winter hexavalent. The gradational decrease in topographical elevation from northern mine area to the southern residential area, combined regional hydrogeological factors and distribution of ultramafic rocks in the northern part of the study area indicate that these toxic trace elements in water were derived from mine dumps.

  18. Potassic-ultrapotassic mafic rocks delineate two lithospheric mantle blocks beneath the southern Peruvian Altiplano

    Science.gov (United States)

    Carlier, G.; Lorand, J. P.; Liégeois, J. P.; Fornari, M.; Soler, P.; Carlotto, V.; Cárdenas, J.

    2005-07-01

    The Altiplano of southern Peru displays a large spectrum of Cenozoic potassic (K) and ultrapotassic (UK) mafic rocks that delineate two deep lithospheric mantle blocks that have undergone different depletion and enrichment events. Phlogopite lamproites indicate that the eastern Altiplano block is underlain by a metasomatized harzburgitic mantle of Paleoproterozoic to Archean age (depleted mantle age, TDM = 1130 2485 Ma; ɛNd = -5.0 to -11.4; 87Sr/86Sri = 0.7100 0.7159). Beneath the western Altiplano block, the presence of a younger (TDM = 837 1259 Ma; ɛNd = +0.6 to -6.3; 87Sr/86Sri = 0.7048 0.7069) metasomatized lherzolitic mantle is deduced from multiple occurrences of diopside-rich K-UK lavas (leucitites, leucite-bearing tephrites, olivine, and diopside trachybasalts). A third suite of young (Cusco Vilcanota fault system separating the western and eastern Altiplano blocks; this third suite, composed of diopside-phlogopite lamproites and augite kersantites, minettes, and trachybasalts, sampled a composite mantle source that probably included an asthenospheric component (TDM = 612 864 Ma; ɛNd = -1.1 to -3.5; 87Sr/86Sri = 0.7051 0.7062), in addition to lithospheric components inherited from the eastern and western Altiplano blocks. The spatial distribution of the south Peruvian K-UK magmatism suggests that K-UK melts reached the surface through reuse of older translithospheric weakness zones extending at least to the depth of magma generation. These latter were reactivated by a dextral transpressional regime imposed on the two rigid lithospheric blocks by the Andean orogen.

  19. Using geochemistry to establish the igneous provenances of the Neogene continental sedimentary rocks in the Central Depression and Altiplano, Central Andes

    Science.gov (United States)

    Pinto, Luisa; Hérail, Gérard; Moine, Bernard; Fontan, François; Charrier, Reynaldo; Dupré, Bernard

    2004-04-01

    Geochemical and mineralogical data from ancient sedimentary strata can be reliable indicators of the provenance of sediments. The heavy mineral assemblages and the major and trace element contents of sedimentary rocks from the Neogene continental successions of the Central Depression in Chile and the Mauri and Corque Basins in the Altiplano of Bolivia reflect volcanic source rocks with different degrees of magmatic differentiation and alkalinity. These results indicate that the source rocks of the Central Depression were less differentiated (andesite to rhyodacite) than those of the Altiplano basins (rhyodacite to rhyolite). The low concentration (cations per formula unit) of total Al (alkaline source rock. By contrast, the high concentration of total Al (>0.15 pfu) and [Ca+Na] (˜0.92 pfu), the variable Ti content (0.01-0.04 pfu) of the clinopyroxenes and the high [Nb/Y] (>0.7) in whole-rock analyses of sandstones from the Mauri Basin indicate erosion of alkaline rock sources. Locally, the low concentration of total Al (<0.15 pfu) in the detrital clinopyroxenes of sandstones from the Corque Basin indicates erosion of a subalkaline source rock. The chemical trends in the sandstones are similar to those in volcanic suites from the Western Cordillera and Eastern Cordillera of the Central Andes.

  20. Salinity modeling by remote sensing in central and southern Iraq

    Science.gov (United States)

    Wu, W.; Mhaimeed, A. S.; Platonov, A.; Al-Shafie, W. M.; Abbas, A. M.; Al-Musawi, H. H.; Khalaf, A.; Salim, K. A.; Chrsiten, E.; De Pauw, E.; Ziadat, F.

    2012-12-01

    Salinization, leading to a significant loss of cultivated land and crop production, is one of the most active land degradation phenomena in the Mesopotamian region in Iraq. The objectives of this study (under the auspices of ACIAR and Italian Government) are to investigate the possibility to use remote sensing technology to establish salinity-sensitive models which can be further applied to local and regional salinity mapping and assessment. Case studies were conducted in three pilot sites namely Musaib, Dujaila and West Garraf in the central and southern Iraq. Fourteen spring (February - April), seven June and four summer Landsat ETM+ images in the period 2009-2012, RapidEye data (April 2012), and 95 field EM38 measurements undertaken in this spring and summer, 16 relevant soil laboratory analysis result (Dujaila) were employed in this study. The procedure we followed includes: (1) Atmospheric correction using FLAASH model; (2) Multispectral transformation of a set of vegetation and non-vegetation indices such as GDVI (Generalized Difference Vegetation Index), NDVI (Normalized Difference Vegetation Index), EVI (Enhanced Vegetation Index), SAVI (Soil Adjusted Vegetation Index), SARVI (Soil Adjusted and Atmospherically Resistant Vegetation Index), NDII (Normalized Difference Infrared Index), Principal Components and surface temperature (T); (3) Derivation of the spring maximum (Musaib) and annual maximum (Dujaila and West Garraf) value in each pixel of each index of the observed period to avoid problems related to crop rotation (e.g. fallow) and the SLC-Off gaps in ETM+ images; (4) Extraction of the values of each vegetation and non-vegetation index corresponding to the field sampling locations (about 3 to 5 controversial samples very close to the roads or located in fallow were excluded); and (5) Coupling remote sensing indices with the available EM38 and soil electrical conductivity (EC) data using multiple linear least-square regression model at the confidence

  1. Molecular hydrogen in the central regions of southern infrared galaxies

    NARCIS (Netherlands)

    Koornneef, J; Israel, FP

    1997-01-01

    An extensive set of molecular hydrogen observations of centers of southern infrared galaxies is presented. Our data are combined with published infrared and radio observations to investigate the relationship between nuclear and circumnuclear activity. We convert the observational data to absolute

  2. A new rock glacier inventory of the Lombardy, Central Alps, Italy

    Science.gov (United States)

    Scotti, R.; Brardinoni, F.; Alberti, S.; Frattini, P.; Crosta, G. B.

    2012-04-01

    The Lombardy Alps, with a surface of 2148 km2 above 2000 m a.s.l. (9% of the total) represents an important portion of the southern side of the orogen. For encompassing a variety of tectonic and climatic regimes, they represent an interesting area to examine environmental controls on periglacial processes. Today, technological developments in remote sensing techniques allow us to study periglacial landforms with increasing detail. We present a new inventory for the whole Lombardy Alps in which we identify and classify rock glaciers and protalus ramparts. The inventory has been conducted by combining a number of remotely-sensed images with field traverses. Specifically, the interpretation of high-resolution (0.5 x 0.5 m) digital aerial photos (2000, 2003, 2007) and a 2 m*2 m Digital Surface Model that cover the whole region has allowed inventorying a greater number of relevant landforms when compared to prior regional efforts. Measurements and photographs taken during fieldwork provided critical ground control for the validation of data extracted from remotely-based analysis. Rock glaciers have been mapped in GIS polygons. The inventory follows the specifics detailed by Scapozza and Mari (2010), with some additional information adapted from the PermaNET evidences guidelines (Cremonese et al., 2011). Landform attributes include, geographic coordinates, mountain sector, type, activity, area, elevation (min, max and mean), slope gradient, slope aspect, dominant lithology, vegetation at the front, and upstream presence/absence of a glacier. In total, we identify 1734 periglacial landforms covering a surface of 81,5 km2 (0,34% of the region). In terms of activity, the inventory includes 673 (39%) intact classified and 1061 (61%) relict landforms. The most common landform typology is the talus-lobate (931, 54%) followed by talus tongue-shaped (436, 25%) and protalus ramparts (232, 13%). Minimum elevation, often considered a good approximation of discontinuous permafrost

  3. Paleomagnetic Evidence for 'Oroclinal' Rotation in the Central Japan Arc from Early Miocene Sedimentary Rocks

    Science.gov (United States)

    Hoshi, H.; Sako, K.; Namikawa, T.; Ando, Y.

    2013-12-01

    In this study we focus on the general curvilinear trend of geologic zones (mainly accretionary complexes) in the central Japan arc. This feature is best represented by the Median Tectonic Line (MTL), a major boundary fault between the Sanbagawa high-P/T and Ryoke low-P/T metamorphic belts. Previous paleomagnetic data imply that the curvature is of 'oroclinal' origin, that is, the curved system was originally straight and formed after the accretionary processes and metamorphism. In order to quantitatively assess this possibility, we have carried out a paleomagnetic study for Early Miocene sedimentary rocks from two areas (Morozaki in Aichi Prefecture and Tomikusa in Nagano Prefecture) in central Japan. In Morozaki, oriented cores were collected at 22 sites from felsic tuff and siltstone beds of the Himaka Formation, which is the lowermost formation of the sedimentary sequence in this area. In Tomikusa, cores were taken at 24 sites from various lithologies of the Tomikusa Group. Rock specimens were subjected to stepwise alternating-field or thermal demagnetization in order to extract characteristic remanent magnetization (ChRM) components. Rock magnetic experiments suggest that ChRMs are carried primarily by magnetite. The Himaka Formation sites have reverse-polarity ChRM directions, and we consider this formation to be correlative to Chronozone C5Dr (18.056-17.533 Ma). The Tomikusa Group indicates both normal and reverse polarities and can be correlated to Chronozone C5D (18.056-17.235 Ma). Mean paleomagnetic directions for the two areas were determined and, together with existing paleomagnetic data from other areas, they were used for a paleomagnetic orocline test with a declination-strike diagram. Our result strongly suggests that the geologic zones and boundary faults (including the MTL) in the central Japan arc was straight before 18 Ma. We suggest that the oroclinal rotation results from a combination of the clockwise rotation of the southwestern Japan arc and

  4. Laboratory Experiments to Evaluate Matrix Diffusion of Dissolved Organic Carbon Carbon-14 in Southern Nevada Fractured-rock Aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, Ronald L. [Nevada University, Reno, NV (United States). Desert Research Institute; Fereday, Wyatt [Nevada University, Reno, NV (United States). Desert Research Institute

    2016-05-01

    Dissolved inorganic carbon (DIC) carbon-14 (14C) is used to estimate groundwater ages by comparing the DIC 14C content in groundwater in the recharge area to the DIC 14C content in the downgradient sampling point. However, because of chemical reactions and physical processes between groundwater and aquifer rocks, the amount of DIC 14C in groundwater can change and result in 14C loss that is not because of radioactive decay. This loss of DIC 14C results in groundwater ages that are older than the actual groundwater ages. Alternatively, dissolved organic carbon (DOC) 14C in groundwater does not react chemically with aquifer rocks, so DOC 14C ages are generally younger than DIC 14C ages. In addition to chemical reactions, 14C ages may also be altered by the physical process of matrix diffusion. The net effect of a continuous loss of 14C to the aquifer matrix by matrix diffusion and then radioactive decay is that groundwater appears to be older than it actually is. Laboratory experiments were conducted to measure matrix diffusion coefficients for DOC 14C in volcanic and carbonate aquifer rocks from southern Nevada. Experiments were conducted using bromide (Br-) as a conservative tracer and 14C-labeled trimesic acid (TMA) as a surrogate for groundwater DOC. Outcrop samples from six volcanic aquifers and five carbonate aquifers in southern Nevada were used. The average DOC 14C matrix diffusion coefficient for volcanic rocks was 2.9 x 10-7 cm2/s, whereas the average for carbonate rocks was approximately the same at 1.7 x 10-7 cm2/s. The average Br- matrix diffusion coefficient for volcanic rocks was 10.4 x 10-7 cm2/s, whereas the average for carbonate rocks was less at 6.5 x 10-7 cm2/s. Carbonate rocks exhibited greater variability in

  5. New paleomagnetic results from Upper Cretaceous arc-type rocks from the northern and southern branches of the Neotethys ocean in Anatolia

    Science.gov (United States)

    Cengiz Cinku, Mualla; Heller, Friedrich; Ustaömer, Timur

    2017-10-01

    A paleomagnetic study of Cretaceous arc type rocks in the Central-Eastern Pontides and in the Southeastern Taurides investigates the tectonic and paleolatitudinal evolution of three volcanic belts in Anatolia, namely the Northern and Southern Volcanic Belts in the Pontides and the SE Taurides volcanic belt. The paleomagnetic data indicate that magnetizations were acquired prior to folding at most sampling localities/sites, except for those in the Erzincan area in the Eastern Pontides. The Southern Volcanic Belt was magnetized at a paleolatitude between 23.8_{-3.8}^{+4.2}°N and 20.2_{-1.2}^{+1.3}°N. Hisarlı (J Geodyn 52:114-128, 2011) reported a more northerly paleolatitude (26.6_{-4.6}^{+5.1}°N) for the Northern Volcanic Belt. The comparison of the new paleomagnetic results with previous ones in Anatolia allows to conclude that the Southern Volcanic Belt in the Central-Eastern Pontides was emplaced after the Northern Volcanic Belt as a result of slab-roll back of the Northern Neotethys ocean in the Late Cretaceous. In the Southeast Taurides, Upper Cretaceous arc-related sandstones were at a paleolatitude of 16.8_{-3.8}^{+4.2} . The Late Cretaceous paleomagnetic rotations in the Central Pontides exhibit a counterclockwise rotation of R± Δ R=-37.1° ± 5.8° (Group 1; Çankırı, Yaylaçayı Formation) while Maastrichtian arc type rocks in the Yozgat area (Group 2) show clockwise rotations R + Δ R = 33.7° ± 8.4° and R + Δ R = 29.3° ± 6.0°. In the SE Taurides counterclockwise and clockwise rotations of R± Δ R=-48.6° ± 5.2° and R± Δ R=+34.1° ± 15.1° are obtained (Group 4; Elazığ Magmatic Complex). The Late Cretaceous paleomagnetic rotations in the Pontides follow a general trend in concordance with the shape of the suture zone after the collision between the Pontides and the Kırşehir block. The affect of the westwards excursion of the Anatolian plate and the associated fault bounded block rotations in Miocene are observed in the east of the

  6. Morphotectonic and petrological variations along the southern Central Indian Ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Mukhopadhyay, R.; Iyer, S.D.; Ray, Dwijesh; Karisiddaiah, S.M.; Drolia, R.K.

    of the segment I, about 160 m above the floor bottom. Interestingly, vesicles on rocks are found filled with zeolites, the largest vesicle was measuring 2 x 20mm. The valley floor is about 6 km wide, and the mound type NVZ shows an elevation between 140... and 160 m. About 10 mm thick glassy veneer with few vesicles was encrusted at times by Fe-Mn oxides and clay. Tectonic Domains: As many as nine well-developed ridge segments, separated by ten discontinuities, were encountered along the stretch...

  7. Detrital zircon study of the Dezful Embayment in the central Zagros, southern Iran

    Science.gov (United States)

    Hsieh, Hao Cheng; Chung, Sun Lin; Talebian, Morteza; Chen, Ling; Zarrinkoub, Mohammad H.; Lee, Hao Yang

    2016-04-01

    The Dezful Embayment of the Zagros Simply Folded Belt (ZFTB) in southern Iran is a foreland basin that formed as a flexural basin during the Miocene by the Zagros orogeny. This study reports a LA-ICPMS analysis of zircon U-Pb geochronology of 13 sedimentary rock samples from the Dezful Embayment, and five others from the Urumieh-Dokhtar magmatic arc (UDMA) and the Sanandaj-Sirjan zone (SSZ). In the northern and central parts of the Dezful Embayment, samples were collected from four principal sedimentary sequences including, from bottom to top, the Gachsaran Formation, Mishan Formation, Agha Jari Formation and Bakhtyari Formation. Our new zircon ages, together with published geochronological data from the UDMA and SSZ, can be used to better constrain the source provenance and tectonic implication of the Dezful Embayment related to the Arabia-Eurasia collision following the closure of Neo-Tethys. Samples of the UDMA and SSZ are characterized by abundant zircon ages of Eocene to Oligocene (55-25 Ma) and Jurassic (176-144 Ma), respectively. In the Dezful Embayment, detrital zircon age populations show significant variations. The age spectra of the northern Embayment show major peaks at the Precambrian (950-550 Ma), Late Carboniferous (323-299 Ma), Jurassic (176-144 Ma) and Eocene to Oligocene (55-25 Ma), with the last two age peaks suggesting an important source provenance from Eurasia, involving the SSZ and UDMA. By contrast, in the central Embayment, detrital zircons are dominated by Precambrian ages (2500 Ma, 1850 Ma, and 950-550 Ma), with rare Jurassic and Cenozoic ages. This suggests a different sedimentary source that we interpret to be the Arabian continent from the south. Moreover, gradual changes in the detrital zircon age spectra and thus in the source provenances are observed in different parts of the Dezful Embayment. The change in the northern Embayment occurred in the Agha Jari Formation, earlier than that in the central Embayment occurring between the

  8. Pre-collisional accretionary growth of the southern Laurasian active margin, Central Pontides, Turkey

    Science.gov (United States)

    Aygül, Mesut; Okay, Aral I.; Oberhänsli, Roland; Sudo, Masafumi

    2016-03-01

    Cretaceous subduction-accretionary complexes crop out over wide areas in the central part of the Pontides, northern Turkey. To the north, the wedge consists of a low-grade metaflysch sequence with blocks of marble, Na-amphibole-bearing metabasite (PT = 7-12 kbar; 400 ± 70 °C) and serpentinite. 40Ar/39Ar phengite ages from the phyllites of the metaflysch are ca. 100 Ma. The metaflysch sequence is underlain by oceanic crust-derived HP/LT metabasites and micaschists along a major detachment fault. The metabasites are epidote-blueschists consisting of glaucophane, epidote, titanite, and phengite locally with garnet. Fresh lawsonite-blueschists are exposed as blocks along the detachment fault. Peak metamorphic conditions of a garnet-blueschist are constrained to 17 ± 1 kbar and 500 ± 40 °C and of a lawsonite-blueschist to 14 ± 2 kbar and 370-440 °C. 40Ar/39Ar phengite dating on the micaschists constrains the HP/LT metamorphism as 101-92 Ma, younging southward. Middle Jurassic (ca. 160 Ma) accretionary complexes consisting of blueschist to lower greenschist facies metabasites, marble and volcanogenic metasediment intercalations are exposed at the southern part of the Cretaceous wedge. In the studied area, the North Anatolian Fault forms the contact between Cretaceous and Middle Jurassic HP/LT metamorphic rocks. Wide distribution of Cretaceous subduction-accretionary complexes implies accretionary tectonic continental growth along the Laurasian active margin. High amount of clastic sediment flux into the trench has a major effect on enlarging the wedge during the Albian. Tectonic thickening of the oceanic HP/LT metamorphic sequence, however, was possibly achieved by propagation of the décollement along the retreating slab which can create the space necessary for progressive deep level basal underplating and extension of the wedge for subsequent syn-subduction exhumation.

  9. Hydrothermally fluoritized Ordovician carbonates as reservoir rocks in the Tazhong area, central Tarim Basin, NW China

    Energy Technology Data Exchange (ETDEWEB)

    Zhijun Jin; Dongya Zhu [Exploration and Production Institute, Beijing (China); Xuefeng Zhang; Wenxuan Hu; Yucai Song [Nanjing University (China). Dept. of Earth Sciences

    2006-01-15

    Reservoir rocks at the Tazhong 45 oil pool, central Tarim Basin, consist of fluoritized carbonate strata of Middle-Late Ordovician age. Petrological observations indicate that the fluorite replaces calcite. Several other hydrothermal minerals accompany the fluorite and include pyrite, quartz, sphalerite and chlorite. Two generations of fluid inclusions are present in the fluorite. Homogenization temperatures (Th) for primary inclusions are mostly between 260{sup o}C and 310{sup o}C, representing the temperature of the hydrothermal fluid responsible for fluorite precipitation. Th for secondary inclusions range from 100{sup o}C to 130{sup o}C, and they represent the hydrocarbon charging temperature as shown by the presence of hydrocarbons trapped in some secondary inclusions. The mineral assemblage and the homogenization temperatures of primary fluid inclusions indicate that the precipitation of fluorite is related to hydrothermal activity in the Tazhong area. Strontium isotope analyses imply that the hydrothermal fluids responsible for fluorite precipitation are related to late-stage magmatic activity, and felsic magmas were generated by mixing of mafic magma and crustal materials during the Permian. Theoretical calculations show that the molecular volume of a carbonate rock decreases by 33.5% when calcite is replaced by fluorite, and the volume shrinkage can greatly enhance reservoir porosity by the formation of abundant intercrystalline pores. Fluoritization has thus greatly enhanced the reservoir quality of Ordovician carbonates in the Tazhong 45 area, so that the fluorite and limestone host rocks in the area have become an efficient hydrocarbon reservoir. According to the modelled burial and thermal history of the Tazhong 45 well, and the homogenization temperatures of secondary fluid inclusions in the fluorite, hydrocarbon charging at the Tazhong 45 reservoir took place in the Tertiary. (author)

  10. Tectonic implications of paleomagnetic poles from Lower Tertiary Volcanic Rocks, south central Alaska

    Science.gov (United States)

    Hillhouse, John W.; Grommé, C. Sherman; Csejtey, Bela, Jr.

    1985-12-01

    We have determined the paleolatitude of lower Tertiary volcanic rocks in southern Alaska to measure possible poleward translation of the Wrangellia and the Peninsular terranes after 50 m.y. ago. Previous paleomagnetic studies have shown that in Triassic and Jurassic time these terranes were located near the equator and have moved at least 3000 km poleward relative to the North American craton. Our sample localities are in the northern Talkeetna Mountains in mildly deformed andesite and dacite flows (50.4, 51.3, 53.9, and 56.3 m.y. by K-Ar) that overlap Lower Cretaceous flysch, Lower Permian volcanic rocks of Wrangellia, and Upper Triassic pillow basalt of the Susitna terrane. Results from 26 cooling units (23 of reversed polarity and 3 of normal polarity) give a mean paleomagnetic pole at 69.5°N, 179.6°E, α95 = 12.2°. Stratigraphic sections from opposite limbs of a syncline yield directional paths that pass the fold test, satisfying a necessary condition for primary origin of the magnetization. The corresponding mean paleolatitude (76°N) of the northern Talkeetna Mountains is 8°±10° higher than the latitude predicted from the Eocene reference pole for North America. Therefore, northward drift of the Talkeetna superterrane, which is the amalgamation of the Wrangellia and Peninsular terranes during and after Middle Jurassic time, was probably complete by 50 m.y. ago. Our results are consistent with paleomagnetic poles from uppermost Cretaceous and Paleocene volcanic sequences in Denali National Park, the Lake Clark region, northern Bristol Bay region, and near McGrath. These poles generally lie south of the cratonic poles, suggesting that the region between the Kaltag, Bruin Bay, and Castle Mountain faults has rotated counterclockwise relative to North America since the early Eocene.

  11. Supracrustal rocks in the Kuovila area, Southern Finland: structural evolution, geochemical characteristics and the age of volcanism

    Directory of Open Access Journals (Sweden)

    Pietari Skyttä

    2005-01-01

    Full Text Available The supracrustal rocks of the Kuovila area in the Palaeoproterozoic Svecofennian Uusimaa Belt, southern Finland, consist mainly of volcaniclastic rocks associated with banded iron formations (BIFs and marbles. Small ZnS and PbS mineralizations are occasionally located within the marbles. Some primary features are well preserved in the sedimentary and volcanic rocks, including lamination in tuffites and banded iron formations. Geochemical results show that the volcanism was bimodal and it mainly had volcanic arc affinity. Specific geochemical indicators suggesting a volcanic arc origin for the Kuovila volcanic rocks include: 1 Enrichment of LILE over the HFSE elements and 2 Distinctly low Nb and Ta contents in relation to Th, Ce and LREE. Geochemistry of the Kuovila area volcanic rocks is very similar to those of the Orijärvi and Kisko formations, located ~15 km NE of Kuovila. Felsic tuff in the Kuovila area was dated at 1891±4 Ma by the U-Pb system on zircons. Consequently volcanism was contemporaneous with magmatism in the adjacent Orijärvi area, thus representing the earliest identified volcanic stage in the southern Svecofennian Uusimaa Belt. Early deformation structures within the Kuovila area are suggested to relate to low-metamorphic or localized low-angle thrusting during D1. F1 folds were recumbent and the S1 cleavages are generally weak. Thrusting was followed by approximately N–S contraction with upright, peak-metamorphic F2 folding overprinting D1 structures and defining the Kuovila synform. Two separate intrusive phases include a synvolcanic granodiorite-diorite-gabbro association and a weakly S2-foliated syn-D2 granodiorite. Anatectic granites and associated migmatizing veins are absent, therefore suggesting that D2 pre-dates the ~1.84–1.82 Ga metamorphic event in the Southern Svecofennian Arc Complex (SSAC. D2 structuresin the Kuovila area are suggested to correlate with the early structures with associated axial planar

  12. A fluid-inclusion study of metamorphosed pelitic and carbonate rocks, south-central Maine

    Energy Technology Data Exchange (ETDEWEB)

    Sisson, V.B. (Rice Univ., Houston, TX (USA)); Hollister, L.S. (Princeton Univ., NJ (USA))

    According to Ferry (e.g., 1987), metamorphosed pelitic and carbonate rocks from south-central Maine record mineral equilibrium with a water-rich fluid; yet, the prograde reactions liberated a CO{sub 2}-rich fluid. This implies a large and pervasive H{sub 2}O influx during the initial stages of metamorphism. Fluid inclusions from twelve quartz segregations of variable metamorphic grade record a complex fluid history. Most of the first-generation fluid inclusions are CO{sub 2}-rich and have densities appropriate to the peak metamorphic conditions. These inclusions may contain the fluid released from prograde decarbonation reactions. In general, composition of the fluid inclusions changes with grade, reflecting limited circulation of the locally derived fluids in fracture networks. In one quartz segregation, the fluid-inclusion composition does vary with rock type in an outcrop. A later influx of H{sub 2}O is recorded by a late generation of fluid inclusions and is associated with hydrothermal alteration of granitic stocks. The late-stage fluids may be triggered retrograde reactions that resulted in the N{sub 2}, N{sub 2}-CO{sub 2}, and CH{sub 4} observed in later generations of fluid inclusions.

  13. Early-Middle Triassic high Sr/Y granitoids in the southern Central Asian Orogenic Belt: Implications for ocean closure in accretionary orogens

    Science.gov (United States)

    Li, Shan; Chung, Sun-Lin; Wilde, Simon A.; Jahn, Bor-Ming; Xiao, Wen-Jiao; Wang, Tao; Guo, Qian-Qian

    2017-03-01

    The key to defining the termination of accretion in an accretionary orogen is to recognize the initial magmatic processes that are generated at the time of ocean closure. We present new age, geochemical, and isotopic data for magmatic rocks related to terminal collision along the Solonker-Xar Moron suture zone in the southern Central Asian Orogenic Belt (CAOB) that record such processes following closure of the Paleo-Asian Ocean. These magmatic rocks were emplaced in the Early-Middle Triassic (251-245 Ma) and show high Sr/Y signatures. Their low MgO, Cr, and Ni contents and variable whole-rock ɛNd(t) values (+5.8 to -5.3), together with the range in zircon ɛHf(t) (+15.6 to -9.8) and δ18O values (5.1 to 7.9‰), indicate an origin from partial melting of juvenile lower crustal rocks with some old components, including supracrustal recycling under garnet amphibolite facies conditions. Our data, along with available geological and geophysical evidence, lead us to propose a model of final oceanic contraction in the southern CAOB, resulting in sublinear distribution of high Sr/Y melts along the resultant collision zone, thus defining the onset of postaccretionary processes in the southern CAOB. The identification of collision-related high Sr/Y granitoids from the southern CAOB not only reveals the magmatic process in response to the final episode of orogenic evolution in the CAOB accretionary collision zone but also constrains how and when an archipelago-type accretionary orogen is terminated.

  14. A detailed rock-magnetic and archeomagnetic study of lime-plasters from central Mexico

    Science.gov (United States)

    Soler-Arechalde, A. M.; Rodriguez, M.; Ramirez, O.; Gogichaishvili, A.; Caballero-Miranda, C.; Hueda-Tanabe, Y.; Urrutia-Fucugauchi, J.

    2003-04-01

    We carried out a reconnaissance rock-magnetic and archeomagnetic investigations of lime-plasters at some most important pre-Hispanic sites in Central Mexico. Both burned and unburned lime plasters (in total 30 samples) were analyzed from Teotihuacan, Tlatelolco, Santa Cruz Atizapan and Pañhu. The characteristic directions determined in this study are considered to be of primary origin. Thermomagnetic investigation show that the remanence is carried in most cases by magnetite or Ti-poor titanomagnetite. Unblocking temperature spectra and relatively high coercivity point to 'small' pseudo-single domain magnetic structure grains as responsible for remanent magnetization. Single-component, linear demagnetization plots were observed in most of cases. The mean site directions are consistent with the available reference master curve for Mesoamerica.

  15. Geologic framework of pre-Cretaceous rocks in the Southern Ute Indian Reservation and adjacent areas, southwestern Colorado and northwestern New Mexico

    Science.gov (United States)

    Condon, Steven M.

    1992-01-01

    This report is a discussion and summary of Jurassic and older rocks in the Southern Ute Indian Reservation and adjacent areas, southwestern Colorado and northwestern New Mexico, and is based on analysis of geophysical logs and observations of outcrops. The Reservation, which is located in the northern San Juan Basin, has been the site of deposition of sediments for much of the Phanerozoic. Geologic times represented on the Reservation are the Precambrian, Cambrian, Devonian, Mississippian, Pennsylvanian, Permian, Triassic, Jurassic, Cretaceous, Tertiary, and Quaternary. Rocks of Ordovician and Silurian age have not been reported in this region. Thicknesses of pre-Cretaceous sedimentary rocks range from about 750 feet (229 meters) on the Archuleta arch, east of the Reservation, to more than 8,300 feet (2,530 meters) just northwest of the Reservation. About 5,500 feet (1,676 meters) of pre-Cretaceous sedimentary rocks occur in the central part of the Reservation, near Ignacio. At Ignacio the top of the Jurassic lies at a depth of 7,600 feet (2,316 meters) below the surface, which is composed of Tertiary rocks. As much as 2,500 feet (762 meters) of Tertiary rocks occur in the area. More than 10,000 feet (3,048 meters) of Cretaceous and younger rocks, and 15,600 feet (4,755 meters) of all Phanerozoic sedimentary rocks occur in the vicinity of the Reservation. In the early Paleozoic the area that includes the Southern Ute Reservation was on the stable western shelf of the craton. During this time sediments that compose the following shallow-marine clastic and carbonate rocks were deposited: the Upper Cambrian Ignacio Quartzite (0-150 feet; 0-46 meters), Upper Devonian Elbert Formation (50-200 feet; 15-61 meters), Upper Devonian Ouray Limestone (10-75 feet; 3-23 meters), and Mississippian Leadville Limestone (0-250 feet; 0-76 meters). Mixed carbonate and clastic deposition, which was punctuated by a unique episode of deposition of evaporite sediments, continued through

  16. 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.

  17. Central Colorado Assessment Project (CCAP)-Geochemical data for rock, sediment, soil, and concentrate sample media

    Science.gov (United States)

    Granitto, Matthew; DeWitt, Ed H.; Klein, Terry L.

    2010-01-01

    This database was initiated, designed, and populated to collect and integrate geochemical data from central Colorado in order to facilitate geologic mapping, petrologic studies, mineral resource assessment, definition of geochemical baseline values and statistics, environmental impact assessment, and medical geology. The Microsoft Access database serves as a geochemical data warehouse in support of the Central Colorado Assessment Project (CCAP) and contains data tables describing historical and new quantitative and qualitative geochemical analyses determined by 70 analytical laboratory and field methods for 47,478 rock, sediment, soil, and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed either in the analytical laboratories of the USGS or by contract with commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects. In addition, geochemical data from 7,470 sediment and soil samples collected and analyzed under the Atomic Energy Commission National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program (henceforth called NURE) have been included in this database. In addition to data from 2,377 samples collected and analyzed under CCAP, this dataset includes archived geochemical data originally entered into the in-house Rock Analysis Storage System (RASS) database (used by the USGS from the mid-1960s through the late 1980s) and the in-house PLUTO database (used by the USGS from the mid-1970s through the mid-1990s). All of these data are maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB and from the NURE database were used to generate most of this dataset. In addition, USGS data that have been excluded previously from the NGDB because the data predate earliest USGS geochemical databases, or were once excluded for programmatic reasons

  18. Carbon storage potential in Pleistocene volcanic rocks of the Magnesia area (Central Greece)

    Science.gov (United States)

    Koutsovitis, Petros; Koukouzas, Nikolaos; Magganas, Andreas

    2017-04-01

    The Porfyrio and Mikrothives volcanoes in the Magnesia area (SE Thessaly, Central Greece) are located a few km (˜8 and 12 km respectively) south-southwest of the industrial area of Volos city and are relatively small in size (˜3 and 10 km2 respectively). They are closely associated with other scattered volcanic centers of Late-Pleistocene-Quaternary age, appearing at the western shores of Pagasitikos gulf and at the Northern Euboikos gulf (e.g. Achilleion, Lichades, Agios Ioannis). This volcanic activity is attributed to back-arc extensional volcanism and may be further associated with propagation tectonics of the North Anatolian fault [1,2,3]. Volcanic rocks from the Porfyrio and Mikrothives mostly consist of basaltic and trachyandesitic lavas and pyroclastic tuffs. Porous basaltic lavas (10-15% porosity) exhibit porphyritic textures with a holocrystalline trachytic groundmass. The groundmass consists of lath-shaped plagioclase crystals, alkali feldspar, clinopyroxene, olivine, oxide minerals (ilmenite, titanomagnetite and magnetite), along with other accessory minerals such as quartz, calcite, apatite and pyrite. Phenocrysts are mostly subhedral and anhedral clinopyroxene crystals (mostly augite and less often diopside), olivine and less often plagioclase and quartz. Cr-spinel crystals have been identified within olivine phenocrysts. Pyroclastic tuffs exhibit vesicular textures, with their porosity varying between 20 and 40%. Their groundmass is hypocrystalline vesicular being either trachytic or aphanitic, often enriched in oxide minerals. Phenocrysts are less frequent compared to the lava samples, most often being feldspars. In some samples, pores are partially filled with secondary calcite. From recent literature it is well known that CO2 can be injected, trapped and retained within the pore spaces of volcanic rocks, forming chemically stable carbonate minerals [4,5,6,7]. The Porfyrio and Mikrothives volcanics can be considered as potential sites for

  19. Early to Middle Devonian granitic and volcanic rocks from the central Gulf of Maine

    Science.gov (United States)

    Barr, Sandra M.; Mortensen, James K.; Thompson, Margaret D.; Hermes, O. Don; White, Chris E.

    2011-10-01

    Cashes Ledge igneous suite in the central Gulf of Maine is represented by 10 granitic and two felsic tuff samples collected from bedrock outcrops using the submersible Alvin in 1971-1972 and archived at the Woods Hole Oceanographic Institute. Laser ablation ICP-MS analyses of zircon grains yielded crystallization ages of 414.9 ± 1.1 Ma and 399.7 ± 1.5 Ma for two alkali feldspar granite samples, 407.0 ± 1.9 Ma for a syenogranite sample, and 384.4 ± 2.3 Ma and 383.9 ± 1.6 Ma for two felsic tuff samples. The samples contain iron-rich mafic minerals, including aegirine-augite, grunerite/ferroedenite, and annite. Most of the samples are alkaline to slightly peralkaline, with high concentrations of SiO 2, Y, Zr, Nb, and REE, strong negative Eu anomalies, and positive epsilon Nd values (1.8 to 3.7). The suite resembles part of a belt of similar Silurian-Devonian rocks with ages between 426 and 370 Ma now recognized in the central part of Avalonia in southeastern New England. They formed in a long-lived, likely extensional regime linked to subduction and subsequent complex transcurrent motions among Ganderia, Avalonia, and Meguma, culminating in the closure of the Rheic Ocean.

  20. Correlation between compositions of ore and host rocks in volcanogenic massive sulfide deposits of the Southern Urals

    Science.gov (United States)

    Seravkin, I. B.

    2013-05-01

    The geology and typification of volcanogenic massive sulfide (VMS) deposits of the Southern Urals are considered. The mineralogical-geochemical types of these deposits correlate with the composition of the underlying igneous rocks: Ni-Co-Cu deposits correlatedwith serpentinites (Ivanovka type); (Co)-Cu deposits, with basalts (Dombarovka type); Cu-Zn deposits, with basalt-rhyolite and basalt-andesite-rhyolite complexes (Ural type); and Au-Ba-Pb-Zn-Cu deposits, with basalt-andesite-rhyolite complexes with predominance of andesitic and felsic volcanics (Baimak type). The Ural-type deposits are subdivided into three subtypes: I, underlain by basalts (Zn-Cu deposits); II, hosted in felsic volcanic rocks of bimodal complexes (Cu-Zn deposits); and III, hosted in felsic volcanic rocks of continuously differentiated complexes (Zn-Cu deposits with Ba, Pb, and As). The above types and subtypes bearing local names are compared with global types of VMS deposits (MAR, Cyprus, Noranda, and Kuroko), to which they are close but not identical.

  1. Relations of zoned pegmatites to other pegmatites, granite, and metamorphic rocks in the southern Black Hills, South Dakota

    Science.gov (United States)

    Norton, J.J.; Redden, J.A.

    1990-01-01

    The pegmatite field and the Harney Peak Granite of the southern Black Hills, South Dakota, form an igneous system that progresses from slightly biotitic muscovite granite through layered pegmatitic granite, with alternating sodic and potassic rocks, to simple plagioclase-quartz-perthite pegmatites, and on to zoned pegmatites. Most of the country rocks are Lower Proterozoic mica schists. At 1700 Ga, intrusion of the Harney Peak Granite created a large dome in these rocks, a thermal aureole with a staurolite, a first sillimanite isograd, and a small area of metamorphism above the second sillimanite isograd. The zoned pegmatites have a strong tendency to occur in clusters, and the types of pegmatites are different in different clusters. A less obvious tendency is a regional zonation in which rare-mineral pegmatites become more abundant and muscovite pegmatites less abundant toward the outskirts of the region. The composition of the granite indicates that its magma originated by partial melting of metasedimentary mica schists similar to those at the present surface. The pegmatitic nature of most of the granite probably reflects exsolution of an aqueous phase. -from Authors

  2. Tertiary plutonic rocks of southern Serbia Vardar Zone as dimension stone

    Directory of Open Access Journals (Sweden)

    Kurešević Lidja

    2014-01-01

    Full Text Available Three granitoid plutons of south-Serbian part of the Vardar Zone, of Tertiary age were studied in order to establish their potential for utilization as dimension stone. These rocks vary in composition from quartzmonconite to quartzdiorite. Field study aimed at establishing the geological factors - presence of fractures, harmful minerals, alterations, jointing type and fabric homogeneity in order to determine the possibility of obtaining large size blocks of stone from the plutons. Laboratory examinations comprised petrological analyses and testing of technical properties. Stone from these plutons has shown favourable results in both field and laboratory examinations. Evaluation of the rock based on obtained laboratory testing results is performed according to technical requirements of the Serbian standard B.B3.200. It has shown that rocks from these plutons can be used as dimension stone for the production of slabs for the exterior and interior paving and cladding. [Projekat Ministarstva nauke Republike Srbije, br. OI176016

  3. Book reviews:Bats of Southern and Central Africa: A Biogeographic ...

    African Journals Online (AJOL)

    Book reviews:Bats of Southern and Central Africa: A Biogeographic and Taxonomic Synthesis by Ara Monadjem, Peter John Taylor, F.P.D. (Woody) Cotterill & M. Corrie Schoeman. Wits University Press, Johannesburg. 2010. Pp. 564. Price R591.00 (paperback).ISBN.

  4. Fluid-rock interaction and thermochemical evolution of the eastern Alice Springs Orogen, central Australia

    Science.gov (United States)

    Varga, Jan; Hand, Martin; Raimondo, Tom; Kelsey, David

    2017-04-01

    The Harts Range rift and basement complex is located in the eastern Alice Springs Orogen, central Australia. For the period 450-320 Ma, this tectonic domain is characterised by large-scale deformation of the Harts Range Group rift sequence and pervasive reworking of its underlying basement. Fluid-rock interaction is evidenced by extensive pegmatite intrusion and retrogression occurring episodically throughout this 130 Myr period, possibly coeval with prograde upper-amphibolite facies metamorphism. The orthogneiss-dominated Entia Gneiss Complex (EGC) represents basement structurally underlying the Harts Range Group, and has evidence for associated deformation and fluid ingress between 390-320 Ma. The EGC also contains metapelites at various structural levels of the mid- to lower-crust, providing a means to constrain the thermobarometric record during a period of significant rheological weakening. Despite existing studies, the source of fluid that contributed to pervasive deformation and metamorphism is unresolved. Additionally, the role of fluid in the episodic history of crustal melting, and ultimately the generation of large-scale tectonic reworking in the Harts Range Group, remains unclear. In this contribution, we integrate U-Pb monazite geochronology, geochemistry, petrography and phase equilibria forward modelling from various metapelitic rocks at different structural levels of the Entia Gneiss Complex. Preliminary data show that the timing of metamorphism coincides with pegmatite crystallisation ages. These constraints form the basis for understanding the conditions and timing at which fluid flow occurred, and the potential sources of the fluid will be constrained by stable isotope analyses (δ18O and δD). The combination of in situ geochronological data with petrographic observations linked to P - T models is vital in providing temporal constraints on the physical and thermal evolution of the reworking event.

  5. Carbon dioxide generation and drawdown during active orogenesis of siliciclastic rocks in the Southern Alps, New Zealand

    Science.gov (United States)

    Menzies, Catriona D.; Wright, Sarah L.; Craw, Dave; James, Rachael H.; Alt, Jeffrey C.; Cox, Simon C.; Pitcairn, Iain K.; Teagle, Damon A. H.

    2018-01-01

    Collisional mountain building influences the global carbon cycle through release of CO2 liberated by metamorphic reactions and promoting mechanical erosion that in turn increases chemical weathering and drawdown of atmospheric CO2. The Southern Alps is a carbonate-poor, siliciclastic mountain belt associated with the active Australian Pacific plate boundary. On-going, rapid tectonic uplift, metamorphism and hydrothermal activity are mobilising carbon. Here we use carbon isotope measurements of hot spring fluids and gases, metamorphic host rocks, and carbonate veins to establish a metamorphic carbon budget. We identify three major sources for CO2 within the Southern Alps: (1) the oxidation of graphite; (2) consumption of calcite by metamorphic reactions at the greenschist-amphibolite facies boundary, and (3) the dissolution of groundmass and vein-hosted calcite. There is only a minor component of mantle CO2 arising on the Alpine Fault. Hot springs have molar HCO3-/Ca2+ ∼9, which is substantially higher than produced by the dissolution of calcite indicating that deeper metamorphic processes must dominate. The total CO2 flux to the near surface environment in the high uplift region of the Southern Alps is estimated to be ∼6.4 × 108 mol/yr. Approximately 87% of this CO2 is sourced from coupled graphite oxidation (25%) and disseminated calcite decarbonation (62%) reactions during prograde metamorphism. Dissolution of calcite and mantle-derived CO2 contribute ∼10% and ∼3% respectively. In carbonate-rich orogens CO2 production is dominated by metamorphic decarbonation of limestones. The CO2 flux to the atmosphere from degassing of hot springs in the Southern Alps is 1.9 to 3.2 × 108 mol/yr, which is 30-50% of the flux to the near surface environment. By contrast, the drawdown of CO2 through surficial chemical weathering ranges between 2.7 and 20 × 109 mol/yr, at least an order of magnitude greater than the CO2 flux to the atmosphere from this orogenic belt

  6. Investigation of genetic structure between deep and shallow populations of the southern Rock Lobster, Jasus edwardsii in Tasmania, Australia.

    Directory of Open Access Journals (Sweden)

    Erin M J Morgan

    Full Text Available The southern rock lobster, Jasus edwardsii, shows clear phenotypic differences between shallow water (red coloured and deeper water (pale coloured individuals. Translocations of individuals from deeper water to shallower waters are currently being trialled as a management strategy to facilitate a phenotypic change from lower value pale colouration, common in deeper waters, to the higher value red colouration found in shallow waters. Although panmixia across the J. edwardsii range has been long assumed, it is critical to assess the genetic variability of the species to ensure that the level of population connectivity is appropriately understood and translocations do not have unintended consequences. Eight microsatellite loci were used to investigate genetic differentiation between six sites (three shallow, three deep across southern Tasmania, Australia, and one from New Zealand. Based on analyses the assumption of panmixia was rejected, revealing small levels of genetic differentiation across southern Tasmania, significant levels of differentiation between Tasmania and New Zealand, and high levels of asymmetric gene flow in an easterly direction from Tasmania into New Zealand. These results suggest that translocation among Tasmanian populations are not likely to be problematic, however, a re-consideration of panmictic stock structure for this species is necessary.

  7. Upper Jurassic to Lower Cretaceous(?) synorogenic sedimentary rocks in the southern Spring Mountains, Nevada

    Science.gov (United States)

    Carr, Michael D.

    1980-08-01

    A newly recognized sequence of Upper Jurassic to Lower Cretaceous(?) terrigenous rocks in the Good-springs district, Nevada, was deposited during the emplacement of the Contact thrust plate. Two facies are recognized: (1) interbedded conglomerate and sandstone derived from Mesozoic igneous and terrigenous platform rocks and (2) interbedded carbonate and sandstone-clast conglomerate, quartz sandstone, and red shale. No igneous detritus occurs in the facies with carbonate-clast conglomerate. Carbonate clasts could only have been derived from the Paleozoic carbonate sequence, which was exposed in the area by latest Jurassic to earliest Cretaceous thrusting. The age of rocks from a volcanic unit within the synorogenic sequence was determined radiometrically to be 150 ± 10 m.y. (K-Ar on biotite). The sequence was deposited disconformably on deeply eroded rocks of the early Mesozoic platform and ultimately overridden from the west by the Contact thrust plate. Information from the sequence corroborates previously reported regional data regarding the timing and nature of the Contact-Red Springs thrust event. *Present address: U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025

  8. Shades of the Rainbow Serpent? A KhoeSan Animal between Myth and Landscape in Southern Africa—Ethnographic Contextualisations of Rock Art Representations

    Directory of Open Access Journals (Sweden)

    Sian Sullivan

    2014-06-01

    Full Text Available The snake is a potent entity in many cultures across the world, and is a noticeable global theme in rock art and inscribed landscapes. We mobilise our long-term ethnographic research with southern African KhoeSan peoples to situate and interpret the presence of snake motifs in the region’s rock art. We contextualise the snake as a transformative ontological mediator between everyday and “entranced” KhoeSan worlds (those associated with “altered states of consciousness”, to weave together both mythological and shamanistic interpretations of southern African rock art. Ethnographic explorations of experiences of snakes as both an aspect of natural history and the physical environment, and as embodiments of multiplicitous and mythical meaning by which to live and understand life, shed light on the presence of snakes and associated snake-themes in southern African rock art. By drawing on ethnographic material, and in conjunction with review of literature, we highlight a dynamic assemblage of extant associations between snakes, rain, water, fertility, blood, fat, transformation, dance and healing. We suggest that these extant associations have explanatory potential for understanding the meaning of these themes in the rock art created by the ancestors of contemporary KhoeSan peoples. Our paper contributes to a live debate regarding the interpretive relevance of ethnography for understanding rock art representations from the past.

  9. Rock Geochemistry and Mineralogy from Fault Zones and Polymetallic Fault Veins of the Central Front Range, Colorado

    Science.gov (United States)

    Caine, Jonathan S.; Bove, Dana J.

    2010-01-01

    During the 2004 to 2008 field seasons, approximately 200 hand samples of fault and polymetallic vein-related rocks were collected for geochemical and mineralogical analyses. The samples were collected by the U.S. Geological Survey as part of the Evolution of Brittle Structures Task under the Central Colorado Assessment Project (CCAP) of the Mineral Resources Program (http://minerals.cr.usgs.gov/projects/colorado_assessment/index.html). The purpose of this work has been to characterize the relation between epithermal, polymetallic mineral deposits, paleostress, and the geological structures that hosted fluid flow and localization of the deposits. The data in this report will be used to document and better understand the processes that control epithermal mineral-deposit formation by attempting to relate the geochemistry of the primary structures that hosted hydrothermal fluid flow to their heat and fluid sources. This includes processes from the scale of the structures themselves to the far field scale, inclusive of the intrusive bodies that have been thought to be the sources for the hydrothermal fluid flow. The data presented in this report are part of a larger assessment effort on public lands. The larger study area spans the region of the southern Rocky Mountains in Colorado from the Wyoming to New Mexico borders and from the eastern boundary of the Front Range to approximately the longitude of Vail and Leadville, Colorado. Although the study area has had an extensive history of geological mapping, the mapping has resulted in a number of hypotheses that are still in their infancy of being tested. For example, the proximity of polymetallic veins to intrusive bodies has been thought to reflect a genetic relation between the two features; however, this idea has not been well tested with geochemical indicators. Recent knowledge regarding the coupled nature of stress, strain, fluid flow, and geochemistry warrant new investigations and approaches to test a variety of

  10. Structural and chemical variations in phlogopite from lamproitic rocks of the Central Mediterranean region

    Science.gov (United States)

    Lepore, Giovanni O.; Bindi, Luca; Pedrazzi, Giuseppe; Conticelli, Sandro; Bonazzi, Paola

    2017-08-01

    Micas from mafic ultrapotassic rocks with lamproitic affinity from several localities of the Central Mediterranean region were studied through single-crystal X-ray diffraction (SC-XRD), electron microprobe analysis (EMPA) and Secondary Ion Mass Spectrometry (SIMS); Mössbauer Spectroscopy (MöS), when feasible, was also applied to minimise the number of unknown variables and uncertainties. Analysed lamproitic samples cover the most important Central Mediterranean type localities, from Plan d'Albard (Western Alps) to Sisco (Corsica), Montecatini Val di Cecina and Orciatico (Tuscany, Italy) and Torre Alfina (Northern Latium, Italy). The studied crystals show distinctive chemical and structural features; all of them belong to the phlogopite-annite join and crystallise in the 1M polytype, except for micas from Torre Alfina, where both 1M and 2M1 polytypes were found. Studied micas have variable but generally high F and Ti contents, with Mg/(Mg + Fe) ranging from 0.5 to 0.9; 2M1 crystals from Torre Alfina radically differ in chemical composition, showing high contents of Ti and Fe as well as of Al in both tetrahedra and octahedra, leading to distinctive structural distortions, especially in tetrahedral sites. SIMS data indicate that studied micas are generally dehydrogenated with OH contents ranging from 0.2 apfu (atoms per formula unit) for Orciatico and Torre Alfina to 1.4 for Plan d'Albard crystals; this feature is also testified by the length of the c parameter, which decreases with the loss of hydrogen and/or the increase of the F → OH substitution. Chemical and structural data suggest that the entry of high charge octahedral cations is mainly balanced by an oxy mechanism and, to a lesser extent, by a M3 +,4 +-Tschermak substitution. Our data confirm that Ti preferentially partitions into the M2 site and that different Ti and F contents, as well as different K/Al values, are both dependant upon fH2O and the composition of magma rather than controlled by P and T

  11. Aptian-Albian boundary in Central Southern Atlas of Tunisia: New tectono-sedimentary facts

    Science.gov (United States)

    Ghanmi, Mohamed Abdelhamid; Barhoumi, Amine; Ghanmi, Mohamed; Zargouni, Fouad

    2017-08-01

    The Aptian-Albian boundary preserves one of the most important events in Central-Southern Atlas of Tunisia, which belongs to the Southern Tethyan margin. A major sedimentary break was recorded between Early Aptian and Albian series in Bouhedma-Boudouaou Mountains. This major hiatus probably linked to the ''Austrian phase'' and to the Aptian and Albian ''Crisis'' testify a period of major tectonic events. In this paper, field observations on the Mid-Cretaceous stratigraphy combined with seismic profile interpretation were used for the first time to characterize the Aptian-Albian boundary in Central-Southern Atlas of Tunisia. Our new results reveal that Aptian-Albian boundary marks a critical interval not only in Maknassy-Mezzouna orogenic system but also in the Tunisian Atlas. Furthermore, Aptian-Albian series outcrop is marked by the important sedimentary gaps as well as a dramatic thickness change from West to East and predominately from North to South. This is linked to the extensional tectonic features which characterize all the Central-Southern Atlas of Tunisia.

  12. Microstructural investigations on carbonate fault core rocks in active extensional fault zones from the central Apennines (Italy)

    Science.gov (United States)

    Cortinovis, Silvia; Balsamo, Fabrizio; Storti, Fabrizio

    2017-04-01

    The study of the microstructural and petrophysical evolution of cataclasites and gouges has a fundamental impact on both hydraulic and frictional properties of fault zones. In the last decades, growing attention has been payed to the characterization of carbonate fault core rocks due to the nucleation and propagation of coseismic ruptures in carbonate successions (e.g., Umbria-Marche 1997, L'Aquila 2009, Amatrice 2016 earthquakes in Central Apennines, Italy). Among several physical parameters, grain size and shape in fault core rocks are expected to control the way of sliding along the slip surfaces in active fault zones, thus influencing the propagation of coseismic ruptures during earthquakes. Nevertheless, the role of grain size and shape distribution evolution in controlling the weakening or strengthening behavior in seismogenic fault zones is still not fully understood also because a comprehensive database from natural fault cores is still missing. In this contribution, we present a preliminary study of seismogenic extensional fault zones in Central Apennines by combining detailed filed mapping with grain size and microstructural analysis of fault core rocks. Field mapping was aimed to describe the structural architecture of fault systems and the along-strike fault rock distribution and fracturing variations. In the laboratory we used a Malvern Mastersizer 3000 granulometer to obtain a precise grain size characterization of loose fault rocks combined with sieving for coarser size classes. In addition, we employed image analysis on thin sections to quantify the grain shape and size in cemented fault core rocks. The studied fault zones consist of an up to 5-10 m-thick fault core where most of slip is accommodated, surrounded by a tens-of-meters wide fractured damage zone. Fault core rocks consist of (1) loose to partially cemented breccias characterized by different grain size (from several cm up to mm) and variable grain shape (from very angular to sub

  13. EARLY STAGE OF THE CENTRAL ASIAN OROGENIC BELT BUILDING: EVIDENCES FROM THE SOUTHERN SIBERIAN CRATON

    OpenAIRE

    D. P. Gladkochub; T. V. Donskaya; Shihong Zhang; S. A. Pisarevsky; A. M. Stanevich; A. M. Mazukabzov; Z. L. Motova

    2017-01-01

    The origin of the Central-Asian Orogenic Belt (CAOB), especially of its northern segment nearby the southern margin of the Siberian craton (SC) is directly related to development and closure of the Paleo-Asian Ocean (PAO). Signatures of early stages of the PAO evolution are recorded in the Late Precambrian sedimentary successions of the Sayan-Baikal-Patom Belt (SBPB) on the southern edge of SC. These successions are spread over 2000 km and can be traced along this edge from north-west (Sayan ...

  14. New constraints on the origin of the ophiolitic rocks within sinorogenic turbiditic sequences at Cilento region (southern Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Mazzeo, F.C.; Vita, P. de; Aulinas, M.; Arienzo, I.; Cirillo, G.; Iovine, R.S.; Spari, D.

    2016-07-01

    Mafic igneous rocks (pillow lavas and gabbros) embedded as olistoliths within Miocene turbiditic sequences crop out in the Cilento area at the Mount Centaurino (Campania region, Southern Italy). The concentration of major oxides, as well as trace element ratios (Nb/Yb, Nb/Ta, Th/Nb) and the chondrite-normalized Rare Earth Elements (REE) patterns suggest a tholeiitic character with Mid Oceanic Ridge Basalts (MORB) affinity. The chemical composition of pillow lavas is consistent with magmas generated by 10% degrees of non-modal fractional partial melting, of a spinel-bearing MORB-type asthenospheric mantle. Regarding gabbros, the calculated composition of parental melts in equilibrium with the clinopyroxenes show a wide compositional range, and there are very different from the pillow basalts of the Mount Centaurino, suggesting that the clinopyroxenes might have derived from more evolved melts compared to those that produced the basalts. The origin of these olistoliths is not yet understood. Here we suggest that these rocks represent fragment of a dismantled accretionary wedge embedded during the deposition of the Cilento group sedimentary successions in a thrust top basin. (Author)

  15. Coastal cliffs, rock-slope failures and Late Quaternary transgressions of the Black Sea along southern Crimea

    Science.gov (United States)

    Pánek, Tomáš; Lenart, Jan; Hradecký, Jan; Hercman, Helena; Braucher, Règis; Šilhán, Karel; Škarpich, Václav

    2018-02-01

    Rock-slope failures represent a significant hazard along global coastlines, but their chronology remains poorly documented. Here, we focus on the geomorphology and chronology of giant rockslides affecting the Crimean Mountains along the Black Sea coast. Geomorphic evidence suggests that high (>100 m) limestone cliffs flanking the southern slopes of the Crimean Mountains are scarps of rockslides nested within larger deep-seated gravitational slope deformations (DSGSDs). Such pervasive slope failures originated due to lateral spreading of intensively faulted Late Jurassic carbonate blocks moving atop weak/plastic Late Triassic flysch and tuff layers. By introducing a dating strategy relying on the combination of the uranium-thorium dating (U-Th) of exposed calcareous speleothems covering the landslide scarps with the 36Cl exposure dating of rock walls, we are able to approximate the time interval between the origin of incipient crevices and the final collapse of limestone blocks that exposed the cliff faces. For the three representative large-scale rockslides between the towns of Foros and Yalta, the initiation of the DSGSDs as evidenced by the widening of crevices and the onset of speleothem accumulation was >300 ka BP, but the recent cliff morphology along the coast is the result of Late Pleistocene/Holocene failures spanning ∼20-0.5 ka BP. The exposures of rockslide scarps occurred mostly at ∼20-15, ∼8, ∼5-4 and ∼2-0.5 ka, which substantially coincide with the last major Black Sea transgressions and/or more humid Holocene intervals. Our study suggests that before ultimate fast and/or catastrophic slope failures, the relaxation of rock massifs correlative with karstification, cracks opening, and incipient sliding lasted on the order of 104-105 years. Rapid Late Glacial/Holocene transgressions of the Black Sea likely represented the last impulse for the collapse of limestone blocks and the origin of giant rockslides, simultaneously affecting the majority

  16. A long-lived Late Cretaceous-early Eocene extensional province in Anatolia? Structural evidence from the Ivriz Detachment, southern central Turkey

    Science.gov (United States)

    Gürer, Derya; Plunder, Alexis; Kirst, Frederik; Corfu, Fernando; Schmid, Stefan M.; van Hinsbergen, Douwe J. J.

    2018-01-01

    Central Anatolia exposes previously buried and metamorphosed, continent-derived rocks - the Kırşehir and Afyon zones - now covering an area of ∼300 × 400 km. So far, the exhumation history of these rocks has been poorly constrained. We show for the first time that the major, >120 km long, top-NE 'Ivriz' Detachment controlled the exhumation of the HP/LT metamorphic Afyon Zone in southern Central Anatolia. We date its activity at between the latest Cretaceous and early Eocene times. Combined with previously documented isolated extensional detachments found in the Kırşehir Block, our results suggest that a major province governed by extensional exhumation was active throughout Central Anatolia between ∼80 and ∼48 Ma. Although similar in dimension to the Aegean extensional province to the east, the Central Anatolian extensional province is considerably older and was controlled by a different extension direction. From this, we infer that the African slab(s) that subducted below Anatolia must have rolled back relative to the Aegean slab since at least the latest Cretaceous, suggesting that these regions were underlain by a segmented slab. Whether or not these early segments already corresponded to the modern Aegean, Antalya, and Cyprus slab segments remains open for debate, but slab segmentation must have occurred much earlier than previously thought.

  17. Paleomagnetism of Late Paleozoic and Mesozoic volcanic rocks of Southern Siberia

    Science.gov (United States)

    Fedyukin, I.; Shatsillo, A.

    2016-12-01

    The main objects of the present study are late Permian and Mesozoic volcanic rocks from Selengin-Vitim volcano-plutonic belt (South Siberia). The belt was formed in the back area of Siberian continent active margin. Volcanic rocks are presented by contrastive volcanites more than 5 km thick. The deposits are subdivided into three suits: Ungurkuy (basalts and andesites), Chernoyar (basalts, andesites and tuffs) and Hilok (basalts, pyroclastic flows and tuffs). The age of Ungurkuy suite is deemed to be between Late Carboniferous and Late Permian. The age of Chernoyar suite is Middle-late Triassic. The age og Hilok suite is Late Jurassic. Volcanic deposits of the three suits were studied to create APWP for the Siberian craton. 250 oriented samples from 40 sites were collected from the Chikoy river valley within South Siberia. All samples were characterized by interpretable paleomagnetic signal. The Ungurkuy suite has different dip and strike: from subhorizontal to 40 degrees inclination and NE course. Chernoyar rocks were collected from monoclinal structure with the dip and strike around NW declination and 5-10 degrees inclination. Hilok suite represents large subhorizontal eruptive bodies. Volcanic rocks of Ungurkuy suite show mostly monopolar (normal polarity) magnetization direction between Early Permian and Permian-Triassic Siberian poles, which indicates its Late Permian age. The normal polarity of the deposits indicates its formation in the period between Kiama superchron, characterized by reversal polarity, and Illavara hyperchron with mixed polarity - 265 Ma. Direction from Chernoyar suite is well-correlated with Late Triassic APWP of Europe, directions of magnetization are bipolar. From Hilok suite several sites show direction of magnetization similar to directions revealed from Early Cretaceous volcanites from nearby area. The magnetization is metachronous. In the other sites the directions of magnetization well-correlated with Late Jurassic APWP of Europe

  18. Rock-Eval pyrolysis and vitrinite reflectance results from the Sheep Creek 1 well, Susitna basin, south-central Alaska

    Science.gov (United States)

    Stanley, Richard G.; Lillis, Paul G.; Pawlewicz, Mark J.; Haeussler, Peter J.

    2014-01-01

    We used Rock-Eval pyrolysis and vitrinite reflectance to examine the petroleum source potential of rock samples from the Sheep Creek 1 well in the Susitna basin of south-central Alaska. The results show that Miocene nonmarine coal, carbonaceous shale, and mudstone are potential sources of hydrocarbons and are thermally immature with respect to the oil window. In the samples that we studied, coals are more organic-rich and more oil-prone than carbonaceous shales and silty mudstones, which appear to be potential sources of natural gas. Lithologically similar rocks may be present in the deeper parts of the subsurface Susitna basin located west of the Sheep Creek 1 well, where they may have been buried deeply enough to generate oil and (or) gas. The Susitna basin is sparsely drilled and mostly unexplored, and no commercial production of hydrocarbons has been obtained. However, the existence of potential source rocks of oil and gas, as shown by our Rock-Eval results, suggests that undiscovered petroleum accumulations may be present in the Susitna basin.

  19. Impacts of climate change on water resources and hydropower systems in central and southern Africa

    Energy Technology Data Exchange (ETDEWEB)

    Hamududu, Byman H.

    2012-11-15

    Climate change is altering hydrological processes with varying degrees in various regions of the world. This research work investigates the possible impacts of climate change on water resource and Hydropower production potential in central and southern Africa. The Congo, Zambezi and Kwanza, Shire, Kafue and Kabompo basins that lie in central and southern Africa are used as case studies. The review of climate change impact studies shows that there are few studies on impacts of climate change on hydropower production. Most of these studies were carried out in Europe and north America and very few in Asia, south America and Africa. The few studies indicate that southern Africa would experience reduction in precipitation and runoff, consequently reductions in hydropower production. There are no standard methods of assessing the resulting impacts. Two approaches were used to assess the impacts of climate change on water resources and hydropower. One approach is lumping changes on country or regional level and use the mean climate changes on mean annual flows as the basis for regional changes in hydropower production. This is done to get an overall picture of the changes on global and regional level. The second approach is a detailed assessment process in which downscaling, hydrological modelling and hydropower simulations are carried out. The possible future climate scenarios for the region of central and southern Africa depicted that some areas where precipitation are likely to have increases while other, precipitation will reduce. The region northern Zambia and southern Congo showed increases while the northern Congo basin showed reductions. Further south in southern African region, there is a tendency of decreases in precipitation. To the west, in Angola, inland showed increases while towards the coast highlighted some decreases in precipitation. On a global scale, hydropower is likely to experience slight changes (0.08%) due to climate change by 2050. Africa is

  20. Potentially Harmful Microalgae from the Southern-Central Coast of Cuba

    OpenAIRE

    Moreira, A.; Reguera, B.; Alonso, C; Comas, A.

    2013-01-01

    Benthic and planktic toxic microalgae from the southern-central region of Cuba were surveyed intermittently between 2007 and 2009, mainly in the estuarine Cienfuegos Bay and its adjacent coast. The highest abundance of both benthic and planktic species were recorded in dry season and at the beginning of the rainy period which is directly correlated with a higher incidence of ciguatera and other episodes associated to harmful algal blooms. Ostreopsis ...

  1. Prevalence, Distributions and Determinants of Obesity and Central Obesity in the Southern Cone of America

    OpenAIRE

    Lanas, Fernando; Bazzano, Lydia; Rubinstein, Adolfo; Calandrelli, Matias; Chen, Chung-Shiuan; Elorriaga, Natalia; Gutierrez, Laura; Manfredi, Jose A.; Seron, Pamela; Mores, Nora; Poggio, Rosana; Ponzo, Jacqueline; Olivera, Hector; He, Jiang; Irazola, Vilma E.

    2016-01-01

    Background Obesity is a major determinant of cardiovascular disease in South America. However, population-based data are limited. Methods A total of 7,524 women and men, aged 35 to 74 years old, were randomly selected from 4 cities in the Southern Cone of Latin America between February 2010 and December 2011. Obesity clinical measurements and cardiovascular risk factors were measured using standard methodology. Results The prevalence of obesity and central obesity were 35.7% and 52.9%, respec...

  2. Predicting climate change extirpation risk for central and southern Appalachian forest tree species

    Science.gov (United States)

    Kevin M. Potter; William W. Hargrove; Frank H. Koch

    2010-01-01

    Climate change will likely pose a severe threat to the viability of certain forest tree species, which will be forced either to adapt to new conditions or to shift to more favorable environments if they are to survive. Several forest tree species of the central and southern Appalachians may be at particular risk, since they occur in limited high-elevation ranges and/or...

  3. Mineral potential of felsic plutonic rocks in the north-central Arabian Shield, Kingdom of Saudi Arabia

    Science.gov (United States)

    Moore, W.J.

    1985-01-01

    Fourteen plutons of Late Proterozoie age potentially favorable for rare-element mineralization have been identified in a geochemical and petrographic assessment of felsic plutonic rocks in the north-central Arabian Shield (lat 23°00'-25°00' N., long 40°00'-45°00' E.). The plutons are highly fractionated, leucocratic granitoids assigned to a major magmatic pulse that spanned the later stages of the Hijaz orogeny (about 610 Ma to about 550 Ma). Most of the targeted plutons are small or not deeply eroded. Two rock types are dominant: subsolvus, muscovite-bearing monzogranite or syenogranite; and hypersolvus, mieroeline perthite granite commonly containing sodic pyriboles. Enrichment in varied suites of the granitophile elements (Sn-W-NbTa-Zr-Y-Th-U) is characteristic. The plutons occupy the central part of a broad arcuate belt of geochemically specialized plutons that conforms generally to the eastern limit of exposed Proterozoic basement.

  4. Post-folding magnetization of the Triassic rocks from western Guizhou and southern Yunnan provinces: New evidence for large clockwise rotations in the Simao Terrane

    Science.gov (United States)

    Huang, Kainian; Opdyke, Neil D.

    2015-08-01

    Thermal demagnetization of the redbed samples collected from the Lower Triassic Feixianguan Formation at two localities in western Guizhou Province reveals that the natural remanent magnetization was dominated by a postfolding component of probably recent origin and the prefolding, possibly primary, component was barely preserved. This confirms that the Feixianguan Fm in western Guizhou and northeastern Yunnan provinces was severely remagnetized. Thermal demagnetization also resolves two postfolding components from the limestone samples of the Mid-Triassic Dashuijingshan Formation from southern Yunnan Province: a low temperature component acquired in recent times and a high temperature component probably acquired shortly after the India-Asia collision. The mean in-situ direction for the high temperature component based on eighteen sites is D = 95.4 °, I = 28.4 ° with α95 = 6.2 °, which indicates a clockwise rotation of 86.3 ± 7.3 ° with respect to stable Eurasia. This result together with paleomagnetic results previously reported from the Jurassic-Eocene rocks in the same area demonstrates beyond reasonable doubt that the central Simao Terrane has experienced large clockwise rotations due to the India's collision with, and continuing penetration into, Asia.

  5. Perception of osteopathic medicine among allopathic physicians in the deep central southern United States.

    Science.gov (United States)

    Reeves, Roy R; Burke, Randy S

    2009-06-01

    Relatively few osteopathic physicians (DOs) practice in the deep central southern geographic region as compared to other parts of the United States. To assess the potential effects of underrepresentation on the perception of osteopathic medicine among allopathic physicians (MDs) in this geographic region. A 20-item, Likert scale survey was designed to evaluate participant perceptions of the osteopathic medical profession. The instrument was mailed to 468 MDs who reside and practice in the deep central southern region of the United States. One hundred seven individuals completed the survey for a response rate of 22.9%. Although the majority of respondents (71 [66.3%]) recognized the distinctiveness of the osteopathic medical profession, they were not necessarily able to articulate these differences clearly through their responses to other survey items. In addition, survey participants expressed was a belief that residency training programs accredited by the Accreditation Council for Graduate Medical Education were more beneficial to osteopathic medical graduates than those approved by the American Osteopathic Association (94 [87.8%]). Finally, there was a perception that research efforts supporting "the scientific basis of osteopathic medicine" were inadequate (53 [49.5%]). The one demographic factor that had a statistically significant (Pperceptions of osteopathic medicine among these MDs was previous contact with DOs. Underrepresentation of DOs in the deep central southern region of the United States appears to have an impact on the perception of osteopathic medicine among MDs insofar as direct or indirect contact with osteopathic physicians led to improved perceptions among this cohort.

  6. Large rock avalanches in southern Perù: the Cerro Caquilluco - Cerrillos Negros rock slide - avalanche (Tacna, Tomasiri, Perù)

    Science.gov (United States)

    Crosta, G.; Hermanns, R. L.; Murillo, P. V.

    2012-04-01

    The Andean bent which coincides with the Peruvian-Chilean border region is characterised by one of the largest relief contrasts on earth with depth of the subduction trench ranging from 5000 to 6000 m below sea level and mountain tops ranging from 5500 to 6300 m a.s.l.. The western flank of the Andes is subdivided in 4 major geologic zones (i.e. Coastal Cordillera, longitudinal Basin or depression, the Precordillera or western escarpment and western Cordillera). Local relief contrasts are also pronounced due to the incision of deep canyons into several million old uplifted surfaces, preserved because of the extremely dry climate with precipitation averaging a few mm and less per year. The Lluta collapse (minimum age of 2.5 Ma; volume 26 km3) is one of the largest non-volcanic non-marine landslides on Earth and has been mapped in that area (Wörner et al., 2002). Systematic mapping in northern Chile and Southern Peru has revealed that this is not the only gigantic landslide in the area but that further landslides of similar size occurred in the area, located both along the canyon slopes and along the western escarpment of the Cordillera. This suggests that landsliding has been a major factor in controlling erosion. This contribution describes first results on mapping a giant landslide complex in southern Perù called the Cerro Caquilluco - Cerrillos Negros Tomasiri rock slide - avalanche complex. The systematic mapping we have carried out in the area is presented in a further contribution to this conference. The Cerro Caquilluco - Cerrillos Negros Tomasiri rock slide - avalanche complex affected the upper part of a SW dipping paleosurface (8° to 9°) cut by a disconnected and regular primitive drainage network organized in a series of SW trending parallel valleys. This network developed within the lower Miocene pinkish tuffaceous deposits of the Huaylillas formation, whereas the main landslide scarp lies within the conglomerates of the Upper Moquegua formation

  7. Characterization of a rock avalanche deposit for risk assessment in the town of Celano (Fucino Basin, Central Italy)

    OpenAIRE

    Rinaldini, A.; Marino, A.; Ciucci, M.

    2008-01-01

    International audience; This paper describes multidisciplinary investigations carried out in the urban centre of Celano, a small town located at the northern edge of the Fucino Basin (Central Italy). The town lies upon a wide debris body that was recognized in this study as a rock avalanche deposit estimated to date to the Holocene. Geomorphologic studies and geophysical investigations led to a detailed characterization of the landslide deposit and the surrounding units. The information obtai...

  8. Deformation Temperature, Kinematics, and Internal Strain during Emplacement of Greater Himalayan Rocks in North-Central and Northeastern Bhutan

    Science.gov (United States)

    Penfold, M. L.; Long, S. P.; Gordon, S. M.; Seward, G.; Agustsson, K. S.; Zeiger, K. J.

    2014-12-01

    Across the Himalayan orogen, high-grade Greater Himalayan (GH) rocks are juxtaposed between low-grade metasedimentary rocks, and the deformation mechanisms that led to their emplacement are debated. In this study, geologic mapping and microstructural analysis are utilized to understand the deformation conditions and exhumation path of GH rocks in northern Bhutan. Three north-south transects of GH rocks were mapped, corresponding to structural thicknesses of 11-15 km, and schist, paragneiss, and quartz veins were the main lithologies sampled and analyzed. Quantitative temperature estimates (~430°C, 545°C, 595°C, and 630°C) from quartz crystallographic preferred-orientation plot opening angles, collected from an electron backscatter diffraction detector on a scanning electron microscope, combined with semi-quantitative deformation temperature estimates obtained from cataloguing quartz recrystallization mechanisms in thin-section, show that GH rocks were initially deformed at temperatures between ~500-750°C, and were later overprinted by a lower-temperature (~400-500°C) recrystallization event. The higher-temperature event is interpreted to be associated with ca. 22-15 Ma displacement on the Main Central thrust, at or near peak metamorphic conditions. The lower-temperature overprint is interpreted to have occurred at a shallower point along the deformation path as GH rocks were exhumed, structurally-elevated, and passively translated southward, concurrent with ca. 18-10 Ma duplexing of Lesser Himalayan rocks. During the multiple stages of deformation, the GH rocks experienced a combination of pure- and simple-shear components of strain, as indicated by multiple outcrops that exhibit both top-to-the-north and top-to-the-south kinematic indicators. In addition, mean kinematic vorticity numbers, obtained from the oblique quartz shape-preferred orientation method, ranged from 0.61-0.94 (22-57% pure shear) during the higher-temperature event and 0.18-0.58 (60

  9. Late sodic metasomatism evidences in bimodal volcanic rocks of the Acampamento Velho Alloformation, Neoproterozoic III, southern Brazil

    Directory of Open Access Journals (Sweden)

    Delia Del Pilar M. de Almeida

    2007-12-01

    Full Text Available A mineralogical study was carried out in mafic and felsic volcanic rocks of the Acampamento Velho Alloformation at Cerro do Bugio, Perau and Serra de Santa Bárbara areas (Camaquã Basin in southern Brazil. The Acampamento Velho bimodal event consists of two associations: lower mafic at the base and upper felsic at the top. Plagioclase and alkali-feldspar were studied using an electronic microprobe, and magnetite, ilmenite, rutile, illite and alkali-feldspar were investigated through scanning electron microscopy. The rocks were affected by a process of late sodic autometasomatism. In mafic rocks, Ca-plagioclase was transformed to albite and pyroxenes were altered. In felsic rocks, sanidine was partially pseudomorphosed, generating heterogeneous alkali-feldspar. In this association, unstable Ti-rich magnetite was replaced by rutile and ilmenite. In mafic rocks, the crystallization sequence was: (1 Ti-rich magnetite (?, (2 pyroxene and Ca-plagioclase, (3 albite (alteration to Ca-plagioclase, (4 sericite, chlorite and calcite (alteration to pyroxene, and kaolinite (alteration to plagioclase/albite. In felsic rocks: (1 zircon, (2 Ti-rich magnetite, (3 sanidine, (4 quartz. The introduction of late Na-rich fluids, generated the formation of (5 heterogeneous alkali-feldspar, (6 ilmenite and rutile from the Ti-rich magnetite, (7 albite in the spherulites. Finally, alteration of sanidine, vitroclasts and pumice to (8 illite.Um estudo mineralógico de detalhe foi realizado nas rochas vulcânicas da Aloformação Acampamento Velho nos Cerros do Bugio, Perau e Serra de Santa Bárbara (Bacia do Camaquã, sudeste do Brasil. Este evento bimodal é constituído por duas associações: máfica inferior na base e félsica superior no topo. Foram estudados grãos de plagioclásio e feldspato alcalino com o uso de microssonda eletrônica, sendo que, magnetita,ilmenita, rutilo e ilita além de feldspato alcalino foram pesquisados através do microscópio eletr

  10. Geochemical correlation of oils and source rocks from central and NE Syria

    Energy Technology Data Exchange (ETDEWEB)

    Abboud, M. [Aleppo University (Syria). Dept. of Geology; University of Oklahoma, Norman, OK (United States). School of Geology and Geophysics; Philp, R.P.; Allen, J. [University of Oklahoma, Norman, OK (United States). School of Geology and Geophysics

    2005-04-01

    Eighteen crude oils and seven source rock samples from the Mesopotamian foredeep, NE Syria, and from the NE Palmyrides in the centre of the country have been characterized by geochemical techniques. The presence of two oil families ('A' and 'B') generated by different source rock types of different ages has been established on the basis of biomarker and carbon isotopic analyses. The data indicates that Groups A and B oils were generated by marine clastic and marine carbonate-evaporitic source rocks, respectively. Group A oils, occurring in Middle Triassic, Middle Jurassic and Upper Cretaceous reservoir rocks in the NE Palmyride area, are geochemically similar to extracts from the Lower Triassic Amanus Shale Formation. Group B oils, which are present in Middle Triassic, Middle Jurassic and Upper Cretaceous reservoirs in the Mesopotamian foredeep, are geochemically similar to extracts of the Middle Triassic Kurra Chine Dolomite and Upper Cretaceous Shiranish Formations. (author)

  11. The relationship between weathering and welding degree of pyroclastic rocks in the Kilistra ancient city, Konya (Central Anatolia, Turkey)

    Science.gov (United States)

    Bozdaǧ, Ali; Bayram, A. Ferat; İnce, İsmail; Asan, Kürşad

    2016-11-01

    Pyroclastic rocks used in both historical and modern structures are inevitably exposed to various weathering processes, leading to damage and destruction of them. To reduce the effects of weathering caused by various atmospheric effects, geologists need to know what processes are more effective and how they affect rock bodies. In this study, our aim is to show the relationship between the weathering and welding degree of pyroclastic rocks, sampled around the Ancient City of Kilistra in Konya (Central Anatolia, Turkey). For this purpose, we conducted field trips, and used petrographic and laboratory techniques such as, physico-mechanical tests and accelerated weathering tests (i.e., Freeze-Thaw, F-T; Wetting-Drying, W-D and Salt Crystallization, SC). Pyroclastic rocks around Kilistra ancient city comprise two different sub-units: the unwelded, lower pyroclastic unit (LPU) and the welded, upper pyroclastic unit (UPU). Following cycles of F-T and SC tests, we observed an increase in porosity values, but a decrease in uniaxial compressive strength values, which was more evident in unwelded-LPU samples. Also, the significant macroscopic textural changes occurred in LPU samples, linked to their unwelded nature. However, physico-mechanical features of both LPU and UPU samples were not significantly changed after W-D tests. Altogether, our findings show that welding degree is one of the main factors controlling weathering and physico-mechanical properties of pyroclastic rocks, and also F-T and SC are more effective processes than W-D on weathering. Accordingly, our approach here could be used to protect the endangered historical structures carved into pyroclastic rocks around the world.

  12. Brucellosis in Terekeka counTy, cenTral equaToria sTaTe, souThern ...

    African Journals Online (AJOL)

    East Africa Medical Journal Vol. 89 No. 1 January 2012. BRUCELLOSIS IN TEREKEKA COUNTY, CENTRAL EQUATORIA STATE, SOUTHERN SUDAN. D. Lado, Ministry of Animal Resources and Fisheries Government of Southern Sudan, Kenya, Field Epidemiology and. Laboratory Training Programme, N. Maina, Jomo ...

  13. From source to sink in central Gondwana: Exhumation of the Precambrian basement rocks of Tanzania and sediment accumulation in the adjacent Congo basin

    OpenAIRE

    Kasanzu, Charles Happe; Linol, Bastien; Maarten J. De Wit; Brown, Roderick; Persano, Cristina; Stuart, Finlay M.

    2016-01-01

    Apatite fission track (AFT) and (U-Th)/He (AHe) thermochronometry data are reported and used to unravel the exhumation history of crystalline basement rocks from the elevated (>1000 m above sea level) but low-relief Tanzanian Craton. Coeval episodes of sedimentation documented within adjacent Paleozoic to Mesozoic basins of southern Tanzania and the Congo basin of the Democratic Republic of Congo indicate that most of the cooling in the basement rocks in Tanzania was linked to erosion. Bas...

  14. C-, Sr-isotope stratigraphy of carbonate rocks from the Southern Espinhaço Ridge, Minas Gerais, southeastern Brazil

    Directory of Open Access Journals (Sweden)

    LUCIO M.S. FRAGA

    2014-06-01

    Full Text Available Neoproterozoic carbonate rocks comprise different stratigraphic units in the southern part of the Espinhaço Ridge, Minas Gerais, Brazil. C, O- and Sr-isotope analyses were carried out along four selected stratigraphic sections across these formations. These are: (i the Rio Pardo Grande Formation in the upper portion of the Espinhaço Supergroup, sampled in section 3; (ii Macaúbas Group laminated limestones (Tijucuçu Farm and dolostone layers (Domingas Formation have been respectively sampled along the so-called sections 1 and 2, and (iii the lower stratigraphic units of the Bambuí Group, sampled in section 4. Laminated limestone samples from the Macaúbas Group have δ13C values as high as 10.9‰ decreasing up section to -1.1‰ and 87Sr/86Sr values vary from 0.7072 to 0.7076, a range commonly observed in Cryogenian rocks. In section 2, dolomitic samples exhibit 87Sr/86Sr from 0.7076 to 0.7077 while in section 3, 87Sr/86Sr from 0.7074 to 0.7079. In section 4, 87Sr/86Sr values are around 0.7080. The values of 87Sr/86Sr observed in carbonate samples from the Macaúbas Group are similar to those observed in the Sr-isotope secular curve for the Neoproterozoic. Carbonate samples from the base of the Bambuí Group correlate with Ediacaran fingerprints, after the Marinoan (ca. 635 Ma glaciation.

  15. Bimodal back-arc alkaline magmatism after ridge subduction: Pliocene felsic rocks from Central Patagonia (47°S)

    Science.gov (United States)

    Espinoza, Felipe; Morata, Diego; Polvé, Mireille; Lagabrielle, Yves; Maury, René C.; Guivel, Christèle; Cotten, Joseph; Bellon, Hervé; Suárez, Manuel

    2008-03-01

    Volumetrically minor microsyenites, alkali microgranite and related trachytic dykes intrude early Pliocene OIB-like alkali basaltic and basanitic flows of the Meseta del Lago Buenos Aires in Central Patagonia (47°S-71°30'W), and occur together with scarce trachytic lava flows. Whole-rock K-Ar ages between 3.98 and 3.08 Ma indicate that the emplacement of these felsic rocks occurred more or less synchronously with that of the post-plateau basaltic sequence that they intrude, during a bimodal mafic-felsic magmatic episode devoid of intermediate compositions. Chemically, these rocks have A 1-type granitoid affinities and are characterized by high silica and alkali contents (60-68 wt.% SiO 2; 8.7-10.8 wt.% Na 2O + K 2O), major and trace elements patterns evidencing evolution by low-pressure fractional crystallization, and Sr and Nd isotopic signatures similar to those of coeval basalts (( 87Sr/ 86Sr) o = 0.70488-0.70571; ( 143Nd/ 144Nd) o = 0.512603-0.512645). Nevertheless, some of them have the most radiogenic Sr values ever reported for a magmatic rock in the Meseta and even in the whole Neogene Patagonian Plateau Lavas province (( 87Sr/ 86Sr) o = 0.70556-0.70571; ( 143Nd/ 144Nd) o = 0.512603-0.512608). In addition, very high contents of strongly incompatible elements in the most evolved rocks, together with Sr isotopic ratios higher than those of coeval basalts, suggest the occurrence of open-system magmatic processes. Continuous fractional crystallization from a primitive basaltic source, similar to post-plateau coeval basalts, towards alkali granites combined with small rates of assimilation of host Jurassic tuffs (AFC) in a shallow magmatic reservoir, best explains the geochemical and petrographic features of the felsic rocks. Therefore, A 1-type magmatic rocks can be generated by open-system crystallization of deep asthenospheric melts in back-arc tectonic settings. In Central Patagonia, these ˜ 3-4 Ma old alkaline intrusions occur aligned along a ˜ N160

  16. Utilization of LANDSAT-8 Data for Lithological Mapping of Basement Rocks of Plateau State North Central Nigeria

    Science.gov (United States)

    Amusuk, D. J.; Hashim, M.; Pour, A. B.; Musa, S. I.

    2016-09-01

    This paper utilized the Landsat-8 image data to map the lithology's of Plateau state north central Nigeria. This is includes the rocks, with particular emphasis on their description and classification. We are living in geologic times and sciences that provide adequate knowledge of the natures of what we live on so as to preserve and have means of sustaining human life. Plateau State is covered by four scenes of Landsat Data, and to describe the lithology's, each scene was processed to produce images. Two different false colour composite images of Landsat-8 (FCC 7, 5 and 3 and BR composites) in RGB were generated and used for the production of 1:100,000 geological map of the study area. The identification of predominant biotitic granitic rocks was revealed and that are distributed along the Jos-Bukuru complex and underlying almost half of the entire state. Moreover, the other rock complexes such as basalts and rhyolites volcanic rocks were also discriminated. This study indicates that Landsat-8 image data has great capability to discriminate lithological units and the production of up-to-date geological maps at regional scale and could be applicable in other regions of the African continent.

  17. UTILIZATION OF LANDSAT-8 DATA FOR LITHOLOGICAL MAPPING OF BASEMENT ROCKS OF PLATEAU STATE NORTH CENTRAL NIGERIA

    Directory of Open Access Journals (Sweden)

    D. J. Amusuk

    2016-09-01

    Full Text Available This paper utilized the Landsat-8 image data to map the lithology’s of Plateau state north central Nigeria. This is includes the rocks, with particular emphasis on their description and classification. We are living in geologic times and sciences that provide adequate knowledge of the natures of what we live on so as to preserve and have means of sustaining human life. Plateau State is covered by four scenes of Landsat Data, and to describe the lithology’s, each scene was processed to produce images. Two different false colour composite images of Landsat-8 (FCC 7, 5 and 3 and BR composites in RGB were generated and used for the production of 1:100,000 geological map of the study area. The identification of predominant biotitic granitic rocks was revealed and that are distributed along the Jos-Bukuru complex and underlying almost half of the entire state. Moreover, the other rock complexes such as basalts and rhyolites volcanic rocks were also discriminated. This study indicates that Landsat-8 image data has great capability to discriminate lithological units and the production of up-to-date geological maps at regional scale and could be applicable in other regions of the African continent.

  18. Distribution, Microfabric, and Geochemical Characteristics of Siliceous Rocks in Central Orogenic Belt, China: Implications for a Hydrothermal Sedimentation Model

    Directory of Open Access Journals (Sweden)

    Hongzhong Li

    2014-01-01

    Full Text Available Marine siliceous rocks are widely distributed in the central orogenic belt (COB of China and have a close connection to the geological evolution and metallogenesis. They display periodic distributions from Mesoproterozoic to Jurassic with positive peaks in the Mesoproterozoic, Cambrian—Ordovician, and Carboniferous—Permian and their deposition is enhanced by the tensional geological settings. The compressional regimes during the Jinning, Caledonian, Hercynian, Indosinian, and Yanshanian orogenies resulted in sudden descent in their distribution. The siliceous rocks of the Bafangshan-Erlihe ore deposit include authigenic quartz, syn-depositional metal sulphides, and scattered carbonate minerals. Their SiO2 content (71.08–95.30%, Ba (42.45–503.0 ppm, and ΣREE (3.28–19.75 ppm suggest a hydrothermal sedimentation origin. As evidenced by the Al/(Al + Fe + Mn, Sc/Th, (La/YbN, and (La/CeN ratios and δCe values, the studied siliceous rocks were deposited in a marginal sea basin of a limited ocean. We suggest that the Bafangshan-Erlihe area experienced high- and low-temperature stages of hydrothermal activities. The hydrothermal sediments of the former stage include metal sulphides and silica, while the latter was mainly composed of silica. Despite the hydrothermal sedimentation of the siliceous rocks, minor terrigenous input, magmatism, and biological activity partly contributed to geochemical features deviating from the typical hydrothermal characteristics.

  19. Semi-automatic mapping of fault rocks on a Digital Outcrop Model, Gole Larghe Fault Zone (Southern Alps, Italy)

    Science.gov (United States)

    Mittempergher, Silvia; Vho, Alice; Bistacchi, Andrea

    2016-04-01

    A quantitative analysis of fault-rock distribution in outcrops of exhumed fault zones is of fundamental importance for studies of fault zone architecture, fault and earthquake mechanics, and fluid circulation. We present a semi-automatic workflow for fault-rock mapping on a Digital Outcrop Model (DOM), developed on the Gole Larghe Fault Zone (GLFZ), a well exposed strike-slip fault in the Adamello batholith (Italian Southern Alps). The GLFZ has been exhumed from ca. 8-10 km depth, and consists of hundreds of individual seismogenic slip surfaces lined by green cataclasites (crushed wall rocks cemented by the hydrothermal epidote and K-feldspar) and black pseudotachylytes (solidified frictional melts, considered as a marker for seismic slip). A digital model of selected outcrop exposures was reconstructed with photogrammetric techniques, using a large number of high resolution digital photographs processed with VisualSFM software. The resulting DOM has a resolution up to 0.2 mm/pixel. Most of the outcrop was imaged using images each one covering a 1 x 1 m2 area, while selected structural features, such as sidewall ripouts or stepovers, were covered with higher-resolution images covering 30 x 40 cm2 areas.Image processing algorithms were preliminarily tested using the ImageJ-Fiji package, then a workflow in Matlab was developed to process a large collection of images sequentially. Particularly in detailed 30 x 40 cm images, cataclasites and hydrothermal veins were successfully identified using spectral analysis in RGB and HSV color spaces. This allows mapping the network of cataclasites and veins which provided the pathway for hydrothermal fluid circulation, and also the volume of mineralization, since we are able to measure the thickness of cataclasites and veins on the outcrop surface. The spectral signature of pseudotachylyte veins is indistinguishable from that of biotite grains in the wall rock (tonalite), so we tested morphological analysis tools to discriminate

  20. Floods of October 1977 in southern Arizona and March 1978 in central Arizona

    Science.gov (United States)

    Aldridge, Byron Neil; Eychaner, James H.

    1984-01-01

    Major floods occurred in October 1977 and March 1978 in Arizona. As much as 14 inches of rain fell during October 6-9, 1977, over the mountains of southern Arizona and northern Mexico resulting in the highest discharge since at least 1892 on the Santa Cruz River upstream from Tucson. The flood inundated areas as much as 4 miles wide, covered at least 16,000 acres of farmland, and caused $15.2 million in damage. Residential losses occurred at Nogales, Amado, Green Valley, and Sahuarita. Severe erosional damage occurred along the Santa Cruz River, Agua Fria Canyon, Potrero Creek, and many small drainages in the Sonoita Creek basin. The peak discharge in Agua Fria Canyon was the highest since before 1900. Less severe flooding occurred along the San Pedro River and the Gila River downstream from the San Pedro. Widespread rainfall of 3 to 6 inches and 9 to 14 inches in some areas in the central mountains during February 27 to March 3, 1978, caused the highest discharge since 1920 on the Salt River in Phoenix and resulted in three deaths. Flooding along the Salt and Gila Rivers and several lesser streams caused statewide damage totaling $65.9 million, of which about $37 million occurred in Maricopa County. Nine counties were declared disaster areas. During the flood of March 1978, moderate peak discharges and unusually high volumes of runoff occurred on tributaries to the Salt and Verde Rivers upstream from a system of reservoirs. Flood magnitudes were greater at the main-stem gaging stations than on the tributaries. The peak discharge into Theodore Roosevelt Lake, which was 21 percent full at the start of the flood, was about 155,000 cubic feet per second, the largest known from 1890 to 1978. The reservoirs stored large quantities of water and greatly reduced the magnitude of the flood. The peak discharge of the Salt River was 125,000 cubic feet per second below Granite Reef Dam and 122,000 cubic feet per second at Phoenix. Discharges in excess of 100,000 cubic feet per

  1. EARLY STAGE OF THE CENTRAL ASIAN OROGENIC BELT BUILDING: EVIDENCES FROM THE SOUTHERN SIBERIAN CRATON

    Directory of Open Access Journals (Sweden)

    D. P. Gladkochub

    2017-01-01

    Full Text Available The origin of the Central-Asian Orogenic Belt (CAOB, especially of its northern segment nearby the southern margin of the Siberian craton (SC is directly related to development and closure of the Paleo-Asian Ocean (PAO. Signatures of early stages of the PAO evolution are recorded in the Late Precambrian sedimentary successions of the Sayan-Baikal-Patom Belt (SBPB on the southern edge of SC. These successions are spread over 2000 km and can be traced along this edge from north-west (Sayan area to south-east (Baikal area and further to north-east (Patom area. Here we present the synthesis of all available and reliable LA-ICP-MS U-Pb geochronological studies of detrital zircons from these sedimentary successions.

  2. Continuous micro-earthquake catalogue of the central Southern Alps, New Zealand

    Science.gov (United States)

    Michailos, Konstantinos; Townend, John; Savage, Martha; Chamberlain, Calum

    2017-04-01

    The Alpine Fault is one of the most prominent tectonic features in the South Island, New Zealand, and is inferred to be late in its seismic cycle of M 8 earthquakes based on paleoseismological evidence. Despite this, the Alpine Fault displays low levels of contemporary seismic activity, with little documented on-fault seismicity. This low magnitude seismicity, often below the completeness level of the GeoNet national seismic catalogue, may inform us of changes in fault character along-strike and might be used for rupture simulations and hazard planning. Thus, compiling a micro-earthquake catalogue for the Southern Alps prior to an expected major earthquake is of great interest. Areas of low seismic activity, like the central part of the Alpine Fault, require data recorded over a long duration to reveal temporal and spatial seismicity patterns and provide a better understanding for the processes controlling seismogenesis. The continuity and density of the Southern Alps Microearthquake Borehole Array (SAMBA; deployed in late 2008) allows us to study seismicity in the Southern Alps over a more extended time period than has ever been done previously. Furthermore, by using data from other temporary networks (e.g. WIZARD, ALFA08, DFDP-10) we are able to extend the region covered. To generate a spatially and temporally continuous catalogue of seismicity in New Zealand's central Southern Alps, we used automatic detection and phase-picking methods. We used an automatic phase-picking method for both P- and S- wave arrivals (kPick; Rawles and Thurber, 2015). Using almost 8 years of seismic data we calculated about 9,000 preliminary earthquake. The seismicity is clustered and scattered and a previously observed seismic gap between the Wanganui and Whataroa rivers is also identified.

  3. Geochronological study of zircons from continental crust rocks in the Frido Unit (southern Apennines)

    Science.gov (United States)

    Laurita, Salvatore; Prosser, Giacomo; Rizzo, Giovanna; Langone, Antonio; Tiepolo, Massimo; Laurita, Alessandro

    2015-01-01

    Zircon crystals have been separated from gneisses and metagranitoids of the Pollino area (southern Apennines) in order to unravel the origin of these crustal slices within the ophiolite-bearing Frido Unit. The morphology of the zircon has been investigated by SEM, and the internal structure was revealed by cathodoluminescence. Data obtained by U/Pb dating have been used to deduce the age and significance of the different crystallization stages of zircon, connected to the evolutionary stages of the continental crust (Late Paleozoic-Early Mesozoic). Zircons in gneisses are characterized by inherited cores of magmatic origin, bordered by metamorphic rims. Inherited zircons generally show Paleoproterozoic to Ordovician ages, indicating the provenance of the sedimentary protolith from different sources. The exclusive presence of Late Neoproterozoic zircon cores in leucocratic gneisses may suggest a different magmatic source possibly connected to Pan-African events. Late Carboniferous-Early Permian ages are found mainly in zircon rims of metamorphic origin. These are similar to the emplacement ages of protolith of the metagranites in the middle crust portion. Late Carboniferous-Early Permian metamorphism and magmatism testify the extensional collapse of the Hercynian belt, recorded in European, particularly, in the Corsica-Sardinia block and in Calabria. Late Permian-Triassic ages have been detected in zircon rims from gneisses and metagranitoids. These younger ages appear related to deformation and emplacement of albite-quartz veins in both lithologies, and are related to an extensional episode predating the Middle Triassic to Middle Jurassic rifting in the Tethyan domain, followed by Middle to Late Jurassic spreading.

  4. Stratigraphic cross sections of the Niobrara interval of the Cody Shale and associated rocks in the Wind River Basin, central Wyoming

    Science.gov (United States)

    Finn, Thomas M.

    2017-02-07

    The Wind River Basin in Wyoming is one of many structural and sedimentary basins that formed in the Rocky Mountain foreland during the Laramide orogeny. The basin is nearly 200 miles long, 70 miles wide, and encompasses about 7,400 square miles in central Wyoming. The basin is bounded by the Washakie Range, Owl Creek uplift, and southern Bighorn Mountains on the north, the Casper arch on the east, the Granite Mountains on the south, and Wind River Range on the west.Many important conventional oil and gas fields producing from reservoirs ranging in age from Mississippian through Tertiary have been discovered in this basin. In addition, an extensive unconventional overpressured basin-centered gas accumulation has been identified in Cretaceous and Tertiary strata in the deeper parts of the basin. It has long been suggested that various Upper Cretaceous marine shales, including the Cody Shale, are the principal hydrocarbon source rocks for many of these accumulations. With recent advances and success in horizontal drilling and multistage fracture stimulation, there has been an increase in exploration and completion of wells in these marine shales in other Rocky Mountain Laramide basins that were traditionally thought of only as hydrocarbon source rocks.The two stratigraphic cross sections presented in this report were constructed as part of a project carried out by the U.S. Geological Survey to characterize and evaluate the undiscovered continuous (unconventional) oil and gas resources of the Niobrara interval of the Upper Cretaceous Cody Shale in the Wind River Basin in central Wyoming. The primary purpose of the cross sections is to show the stratigraphic relationship of the Niobrara equivalent strata and associated rocks in the lower part of the Cody Shale in the Wind River Basin. These two cross sections were constructed using borehole geophysical logs from 37 wells drilled for oil and gas exploration and production, and one surface section along East Sheep Creek

  5. Prevalence, Distributions and Determinants of Obesity and Central Obesity in the Southern Cone of America.

    Directory of Open Access Journals (Sweden)

    Fernando Lanas

    Full Text Available Obesity is a major determinant of cardiovascular disease in South America. However, population-based data are limited.A total of 7,524 women and men, aged 35 to 74 years old, were randomly selected from 4 cities in the Southern Cone of Latin America between February 2010 and December 2011. Obesity clinical measurements and cardiovascular risk factors were measured using standard methodology.The prevalence of obesity and central obesity were 35.7% and 52.9%, respectively. The prevalence of obesity and central obesity were higher in women, and even higher in women with lower education compared with women with higher education. In men and women obesity was associated with a higher prevalence of diabetes, odds ratio (OR 2.38 (95% Confidence Interval [CI]: 1.86 to 3.05 and 3.01 (95%CI 2.42 to 3.74 respectively, hypertension (OR 2.79 (95%CI 2.32 to 3.36 and 2.40 (95%CI 2.05 to 2.80 respectively, dyslipidemia (OR 1.83 (95%CI 1.50 to 2.24 and 1.69 (95%CI 1.45 to 1.98, respectively, low physical activity (OR 1.38(95%CI 1.14 to 1.68 and 1.38 (95%CI 1.18 to 1.62 respectively and a lower prevalence of smoking (OR, 0.65 (95%CI 0.53 to 0.80 and 0.58(95%CI 0.48 to 0.70 respectively.Obesity and central obesity are highly prevalent in the general population in the Southern Cone of Latin America and are strongly associated with cardiovascular risk factor prevalence. These data suggest that efforts toward prevention, treatment, and control of obesity should be a public health priority in the Southern Cone of Latin America.

  6. Prevalence, Distributions and Determinants of Obesity and Central Obesity in the Southern Cone of America.

    Science.gov (United States)

    Lanas, Fernando; Bazzano, Lydia; Rubinstein, Adolfo; Calandrelli, Matias; Chen, Chung-Shiuan; Elorriaga, Natalia; Gutierrez, Laura; Manfredi, Jose A; Seron, Pamela; Mores, Nora; Poggio, Rosana; Ponzo, Jacqueline; Olivera, Hector; He, Jiang; Irazola, Vilma E

    2016-01-01

    Obesity is a major determinant of cardiovascular disease in South America. However, population-based data are limited. A total of 7,524 women and men, aged 35 to 74 years old, were randomly selected from 4 cities in the Southern Cone of Latin America between February 2010 and December 2011. Obesity clinical measurements and cardiovascular risk factors were measured using standard methodology. The prevalence of obesity and central obesity were 35.7% and 52.9%, respectively. The prevalence of obesity and central obesity were higher in women, and even higher in women with lower education compared with women with higher education. In men and women obesity was associated with a higher prevalence of diabetes, odds ratio (OR) 2.38 (95% Confidence Interval [CI]: 1.86 to 3.05) and 3.01 (95%CI 2.42 to 3.74) respectively, hypertension (OR 2.79 (95%CI 2.32 to 3.36) and 2.40 (95%CI 2.05 to 2.80) respectively, dyslipidemia (OR 1.83 (95%CI 1.50 to 2.24) and 1.69 (95%CI 1.45 to 1.98), respectively, low physical activity (OR 1.38(95%CI 1.14 to 1.68) and 1.38 (95%CI 1.18 to 1.62) respectively and a lower prevalence of smoking (OR, 0.65 (95%CI 0.53 to 0.80) and 0.58(95%CI 0.48 to 0.70) respectively. Obesity and central obesity are highly prevalent in the general population in the Southern Cone of Latin America and are strongly associated with cardiovascular risk factor prevalence. These data suggest that efforts toward prevention, treatment, and control of obesity should be a public health priority in the Southern Cone of Latin America.

  7. Prevalence, Distributions and Determinants of Obesity and Central Obesity in the Southern Cone of America

    Science.gov (United States)

    Bazzano, Lydia; Rubinstein, Adolfo; Calandrelli, Matias; Chen, Chung-Shiuan; Elorriaga, Natalia; Gutierrez, Laura; Manfredi, Jose A.; Seron, Pamela; Mores, Nora; Poggio, Rosana; Ponzo, Jacqueline; Olivera, Hector; He, Jiang; Irazola, Vilma E.

    2016-01-01

    Background Obesity is a major determinant of cardiovascular disease in South America. However, population-based data are limited. Methods A total of 7,524 women and men, aged 35 to 74 years old, were randomly selected from 4 cities in the Southern Cone of Latin America between February 2010 and December 2011. Obesity clinical measurements and cardiovascular risk factors were measured using standard methodology. Results The prevalence of obesity and central obesity were 35.7% and 52.9%, respectively. The prevalence of obesity and central obesity were higher in women, and even higher in women with lower education compared with women with higher education. In men and women obesity was associated with a higher prevalence of diabetes, odds ratio (OR) 2.38 (95% Confidence Interval [CI]: 1.86 to 3.05) and 3.01 (95%CI 2.42 to 3.74) respectively, hypertension (OR 2.79 (95%CI 2.32 to 3.36) and 2.40 (95%CI 2.05 to 2.80) respectively, dyslipidemia (OR 1.83 (95%CI 1.50 to 2.24) and 1.69 (95%CI 1.45 to 1.98), respectively, low physical activity (OR 1.38(95%CI 1.14 to 1.68) and 1.38 (95%CI 1.18 to 1.62) respectively and a lower prevalence of smoking (OR, 0.65 (95%CI 0.53 to 0.80) and 0.58(95%CI 0.48 to 0.70) respectively. Conclusions Obesity and central obesity are highly prevalent in the general population in the Southern Cone of Latin America and are strongly associated with cardiovascular risk factor prevalence. These data suggest that efforts toward prevention, treatment, and control of obesity should be a public health priority in the Southern Cone of Latin America. PMID:27741247

  8. Space geodetic measurement of crustal deformation in central and southern California, 1984-1992

    Science.gov (United States)

    Feigl, Kurt L.; Agnew, Duncan C.; Bock, Yehuda; Dong, Danan; Donnellan, Andrea; Hager, Bradford H.; Herring, Thomas A.; Jackson, David D.; Jordan, Thomas H.; King, Robert W.

    1993-01-01

    We estimate the velocity field in central and southern California using Global Positioning System (GPS) observations from 1986 to 1992 and very long baseline interferometry (VLBI) observations from 1984 to 1991. Our core network includes 12 GPS sites spaced approximately 50 km apart, mostly in the western Transverse Ranges and the coastal Borderlands. The precision and accuracy of the relative horizontal velocities estimated for these core stations are adequately described by a 95% confidence ellipse with a semiminor axis of approximately 2 mm/yr oriented roughly north-south, and a semimajor axis of approximately 3 mm/yr oriented east-west.

  9. Isotopic studies of beach rock carbonates from Konkan, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, B.; Rajamanickam, G.V.; Gujar, A.R.

    The beach rock carbonates from the 200 km long stretch from Guhagar in the north to Deogad in the south along the Konkan coast (Maharashtra, India) are studied for sup(14)C dating and sup(13)C : sup(12)C and sup(18)O : sup(16)O ratio determination...

  10. Stratigraphical and sedimentary characters of Late Cretaceous formations outcropping in central and southern Tunisia, Tethyan southern margin

    Science.gov (United States)

    Jaballah, J.; Negra, M. H.

    2016-12-01

    The main goals of our approach are to identify some local to global events in relation with tectonic instabilities and/or sea-level changes, occurring during the deposition of Cenomanian-Coniacian carbonate series in Tunisia. Several sections surveyed in Central-Southern Tunisia, along a North-South transect extending from Sidi Bouzid to Gafsa area, show that the Cenomanian-Coniacian series include rudist-rich facies associated to other shallow marine to deeper deposits. Detailed sedimentological studies supported by new biostratigraphical data (provided by H. Bismuth, oral comm.), have allowed to add more precisions on the lithostratigraphical stacking and thus on the Central Tunisia Stratigraphic Chart. Some carbonate members such as the Middle Turonian Bireno and the Late Turonian-Coniacian Douleb have been identified in certain localities for the first time. Indeed, these members were never described before at Jebel el Kébar and Jebel Meloussi. In the Sidi Bouzid area, especially at Jebel el Kébar, the Cenomanian-Coniacian carbonate members are characterized by frequent and rapid changes, related to the existence of highs (horsts, probably) and depressed depositional domains (grabens, probably), which formed during the deposition of the two lower Units of the Middle Turonian Bireno Member. Above, the Late Turonian to Coniacian deposits, have tended to seal the irregular paleotopography affected, at least locally, by Middle Turonian extensional tectonic movements. They could be related, in contrast, to a drowning linked to a sea level rise. Similar events were described abroad during Late Turonian times; a partial drowning of carbonate platforms was already identified in other localities of the African Tethyan margin. However, the global drowning corresponding to the C/T event was not identified in the present study, although previous works have described this event North of the studied sector. As demonstrated in other localities, a global eustatic event could

  11. Age of the Xalnene Ash, Central Mexico: A Rock Magnetic Perspective

    Science.gov (United States)

    Feinberg, J. M.; Renne, P. R.; Waters, M. R.; Arroyo-Cabrales, J.; Ochoa-Castillo, P.; Perez-Campo, M.

    2007-05-01

    Features interpreted as human footprints ~40 ka old have been reported from the Toluquilla quarry near Valsequillo Reservoir, 15 km south of the city of Puebla in central Mexico (Gonzalez et al., 2006). The indentations were found in an indurated basaltic lapilli tuff informally known as the Xalnene Ash. The ~40 ka age of the tuff was based on optically stimulated luminescence (OSL) analysis of baked quartz-rich materials incorporated into the ash during eruption. If true, this ~40 ka age suggests that humans migrated into the Americas at a far earlier time than is currently believed. In contrast to the conclusions of Gonzalez et al. (2006), the age of the Xalnene ash was determined as 1.30 ± 0.03 Ma (2σ) based on highly reproducible 40Ar/39Ar analyses of homogenous basaltic lapilli (Renne et al., 2005). This age is further supported by paleomagnetic data, which shows a reversed polarity for the Xalnene Ash, consistent with deposition during chron C1r.2r (1.77 to 1.07 Ma). The magnetic mineralogy within the Xalnene Ash is not straightforward, and is a reflection of its volcanic origin modified by its subsequent hydrous alteration via prolonged exposure to varying water levels in Lake Valsequillo. Submicron titanomagnetite grains occur within the cores of the lapilli and are characterized by Curie temperatures between 400-500 °C corresponding to unoxidized compositions ranging from Fe2.82Ti0.18O4 to Fe2.68Ti0.32O4. Two components of magnetization were revealed during progressive alternating field (AF) demagnetization of oriented, individual lapilli: a low coercivity, reversed component that is typically removed after 15-20 mT, and a randomly oriented, but well-defined, higher coercivity component. The directions associated with the low coercivity component are consistent with the direction of the bulk rock characteristic remanent magnetization. This low coercivity component may have been acquired immediately after deposition during the final stages of cooling, or

  12. Geo-engineering evaluation of Termaber basalt rock mass for crushed stone aggregate and building stone from Central Ethiopia

    Science.gov (United States)

    Engidasew, Tesfaye Asresahagne; Barbieri, Giulio

    2014-11-01

    The geology of the central part of Ethiopia exhibits a variety of rock types that can potentially be developed for construction stone production, of which the most wide spread and important one is the Termaber basalt. Even though some preliminary work is done on these rocks towards construction material application, it remains largely that this resource is untouched and needs further scientific characterization for the use in large scale industrial application. Basaltic rocks have been widely used in many parts of the world as concrete aggregate and dimension stone for various civil structures. The present research study was carried out for Geo-engineering evaluation of Termaber basalt rock mass for crushed stone aggregate and building stone from Central Ethiopia (around Debre Birhan). The main objective of the present research study was to assess the general suitability of the Termaber basalt to be used as coarse aggregate for concrete mix and/or to utilize it as cut stone at industrial level. Only choice made with full knowledge of the basic characteristics of the material, of its performance and durability against the foreseen solicitations will ensure the necessary quality of the stone work and thereby a possibility to reach its intended service life. In order to meet out the objective of the present study, data from both field and laboratory were collected and analyzed. The field data included geological investigations based on different methods and sample collection while the laboratory work included, uniaxial compressive strength, ultrasonic pulse velocity, dynamic elasticity modulus, bulk density, water absorption, specific gravity, open porosity, aggregate impact value, petrographic examination and XRF, aggregate crushing value, Los Angeles abrasion value, sodium sulfate soundness, X-ray diffraction and alkali silica reactivity tests. The field and laboratory data were compiled and compared together to reveal the engineering performance of the rock mass in

  13. Landform transitions from pronival ramparts to moraines and rock glaciers: A case study from the Smørbotn cirque, Romsdalsalpane,\\ud southern Norway

    OpenAIRE

    Matthews, J.A.; Wilson, P; Mourne, R. W.

    2017-01-01

    Landform transitions are defined as intermediate forms that represent transient developmental stages between conventional landform types. This study evaluates possible cases of landform transitions from pronival (protalus) ramparts to moraine ridges, and from pronival ramparts to lobate rock glaciers (protalus lobes) at the foot of the headwall of Smørbotn cirque in southern Norway. The five landforms had been previously classified as pronival ramparts. We conclude that only two (Smørbotn 2 a...

  14. Characterization of a rock avalanche deposit for risk assessment in the town of Celano (Fucino Basin, Central Italy

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    A. Rinaldini

    2008-01-01

    Full Text Available This paper describes multidisciplinary investigations carried out in the urban centre of Celano, a small town located at the northern edge of the Fucino Basin (Central Italy. The town lies upon a wide debris body that was recognized in this study as a rock avalanche deposit estimated to date to the Holocene. Geomorphologic studies and geophysical investigations led to a detailed characterization of the landslide deposit and the surrounding units. The information obtained was used to assess the vulnerability of the Celano municipal area, by evaluating the stability of the landslide body and the behaviour of its lithologies under seismic loads.

  15. Mycocoenology in Abies alba Miller woods of central-southern Tuscany (Italy

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    Angela Laganà

    2014-01-01

    Full Text Available Numerous reports indicate that fir woods in central and northern Europe have recently been damaged by increasing pollution. It has been demonstrated that fungi can be good bioindicators of forest health status. In polluted areas the production of fruit bodies generally declines and the fungal biodiversity, especially of symbiotic species, is reduced. Here we report the results of a survey of the fungal and plant communities in woods of Abies alba Miller in central-southern Tuscany, already studied in the past. Certain changes were observed in the study areas, but they seem more likely to be due to other factors than pollution, such as the weather conditions, the age and natural evolution of the forests towards their climax.

  16. Mapping the productive sands of Lower Goru Formation by using seismic stratigraphy and rock physical studies in Sawan area, southern Pakistan: A case study

    KAUST Repository

    Munir, K.

    2011-02-24

    This study has been conducted in the Sawan gas field located in southern Pakistan. The aim of the study is to map the productive sands of the Lower Goru Formation of the study area. Rock physics parameters (bulk modulus, Poisson\\'s ratio) are analysed after a detailed sequence stratigraphic study. Sequence stratigraphy helps to comprehend the depositional model of sand and shale. Conformity has been established between seismic stratigraphy and the pattern achieved from rock physics investigations, which further helped in the identification of gas saturation zones for the reservoir. Rheological studies have been done to map the shear strain occurring in the area. This involves the contouring of shear strain values throughout the area under consideration. Contour maps give a picture of shear strain over the Lower Goru Formation. The identified and the productive zones are described by sands, high reflection strengths, rock physical anomalous areas and low shear strain.

  17. A High-Resolution Map of Emerald Ash Borer Invasion Risk for Southern Central Europe

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    Viktoria Valenta

    2015-08-01

    Full Text Available Ash species (Fraxinus spp. in Europe are threatened by the Emerald Ash Borer (Agrilus planipennis, EAB, an invasive wood boring beetle native to East Asia and currently spreading from European Russia westwards. Based on a high-resolution habitat distribution map (grid cell size: 25 × 25 m and data on distribution and abundance of Common Ash (Fraxinus excelsior, the most widespread and highly susceptive host species of EAB in Europe, we assess the spatial distribution of EAB invasion risks for southern Central Europe (Austria, Switzerland, Liechtenstein, southern Germany, South Tyrol. We found highest F. excelsior abundance and thus invasion risks in extensive lowland floodplain forests, medium risks in zonal lowland forests and low risks in upper montane and subalpine forests. Based on average velocities of spread in Russia (13–31 km/year and North America (2.5–80 km/year from flight and human-assisted transport, EAB is likely to cover the distance (1500 km between its current range edge in western Russia and the eastern border of the study region within few decades. However, secondary spread by infested wood products make earlier introductions likely. The high susceptibility and mortality of F. excelsior leave no doubt that this beetle will become a major forest pest once it reaches Central Europe. Therefore, developing and testing management approaches with the aim to halt or at least slow down the invasion of EAB in Europe have to be pursued with great urgency.

  18. Molecular characterization of an endolithic microbial community in dolomite rock in the central Alps (Switzerland).

    Science.gov (United States)

    Horath, Thomas; Bachofen, Reinhard

    2009-08-01

    Endolithic microorganisms colonize the pores in exposed dolomite rocks in the Piora Valley in the Swiss Alps. They appear as distinct grayish-green bands about 1-8 mm below the rock surface. Based on environmental small subunit ribosomal RNA gene sequences, a diverse community driven by photosynthesis has been found. Cyanobacteria (57 clones), especially the genus Leptolyngbya, form the functional basis for an endolithic community which contains a wide spectrum of so far not characterized species of chemotrophic Bacteria (64 clones) with mainly Actinobacteria, Alpha-Proteobacteria, Bacteroidetes, and Acidobacteria, as well as a cluster within the Chloroflexaceae. Furthermore, a cluster within the Crenarchaeotes (40 clones) has been detected. Although the eukaryotic diversity was outside the scope of the study, an amoeba (39 clones), and several green algae (51 clones) have been observed. We conclude that the bacterial diversity in this endolithic habitat, especially of chemotrophic, nonpigmented organisms, is considerable and that Archaea are present as well.

  19. Interaction of Rahaliya-Ekhedhur groundwater with the aquifer rock, West Razzaza Lake, Central Iraq

    Science.gov (United States)

    Al-Dabbas, Moutaz A.

    2017-10-01

    The groundwater of Dammam aquifer in Rahaliya-Ekhedhur area, West Razzaza, Iraq, was studied to identify the main hydrogeochemical processes and the groundwater-rock interaction. The results indicated that Na+ and SO4 2- are the dominant ions in the groundwater. The average contribution of cations in the aquifer is Na+ + K+ (24.7 %), Ca2+ (13.9 %), and Mg2+ (11.4 %), while anions contribution is SO4 2- (23.0 %), Cl- (20.7 %), and HCO3 - (6.3 %). The groundwater characterized by neutral to slightly alkaline hard water, excessively mineralized, and slightly brackish water type. Rock-water interaction processes are identified to include dissolution of carbonates, sulfates, halite, and clay minerals, leaching, and cation exchanges, with little impact of evaporation.

  20. Modeling of petrological and geophysical rock parameters in the Central Eastern Alps

    Science.gov (United States)

    Wind, Sandra; Bousquet, Romain; Götze, Hans-Jürgen; Schmidt, Sabine

    2017-04-01

    Intensely studied regions as the Alps allow interdisciplinary approaches for better understanding complex structure of the lithosphere in orogens. For this reason a geophysical 3D-density model of the Eastern Alps has been reworked from the petrological perspective. By modeling the metamorphic density of rocks using the Theriak-Domino software package the influence of temperature, pressure and chemical composition on the density has been analysed. Density-isopleth-plots of orthogneisses, metabasites, ultramafics and metapelites, which are typical rocks of the Tauern Window, have been calculated showing characteristic density trends for each rock type, depending on stable mineralogical phases and changes of reactions influenced by the chemical composition. To further investigation the influence of the chemical composition on rock densities various Zentralgneiss samples were analysed. Chemical compositions of 45 Zentralgneiss samples from literature were used in addition to five reworked and newly measured samples. By the usage of the corresponding thin sections, information on the metamorphic grade, weathering state and water content were gained. For the used temperature and pressure conditions a complex relation between the density and composition was observed, depending mainly on an increasing iron content. Based on the petrological findings a geophysical density model has been reinvestigated using the IGMAS+ software. With respect to the results of the TRANSALP working group and information about the Moho depth, a good correlation between the measured and modeled gravity field was reached in the new petrological 3D-density model. This model has been used to further analyse the impact of the Zentralgneiss unit on the short waves of the modeled gravity field, resulting in a shifting to a lower gravity anomaly of -15 % and +8 % for the calculated maximum and minimum density. In this study we emphasize the importance of multidisciplinary approaches to enable good

  1. Optical hyperspectral measurements of rocks and soils in Central Srednogorie, Bulgaria

    Science.gov (United States)

    Borisova, Denitsa; Banushev, Banush; Petkov, Doyno; Nedkov, Roumen; Avetisyan, Daniela

    2017-09-01

    Remote sensing is the technique of acquiring, processing, and interpreting images and multi channels spectral data, acquired from optical imager sensors mounted on aircraft and satellite platforms recording the interaction between investigated objects and electromagnetic energy. Remote sensing application in Earth observation begins with the design and development of equipment for carrying out research of the monitored objects remotely and without disturbing their integrity. Ground-truth data in Earth observation of the environment and in the remote sensing investigations are very important. In this work remote sensing images are used for mineral exploration in different applications for mapping geology and recognizing soils and rocks by their spectral signatures. We are used Landsat, ASTER and Sentinel satellites images used to interpret both structures, soils and rocks. For data verification hyperspectral systems USB 2000 and NIRQUEST 512.2 of Ocean Optics Inc. are used in laboratory and field spectrometric measurements. They provide to define finest spectral characteristics of soil minerals and rocks for their identification. The obtained spectral data are compared with similar data from different instruments for Earth observation included in the spectral libraries. They correspond to the shape of the spectral signature in the same spectral range obtained with other spectrometers. These promising results encourage us to plan the next campaigns for the field spectroscopy measurements in different regions of Bulgaria.

  2. Reliable yields of public water-supply wells in the fractured-rock aquifers of central Maryland, USA

    Science.gov (United States)

    Hammond, Patrick A.

    2018-02-01

    Most studies of fractured-rock aquifers are about analytical models used for evaluating aquifer tests or numerical methods for describing groundwater flow, but there have been few investigations on how to estimate the reliable long-term drought yields of individual hard-rock wells. During the drought period of 1998 to 2002, many municipal water suppliers in the Piedmont/Blue Ridge areas of central Maryland (USA) had to institute water restrictions due to declining well yields. Previous estimates of the yields of those wells were commonly based on extrapolating drawdowns, measured during short-term single-well hydraulic pumping tests, to the first primary water-bearing fracture in a well. The extrapolations were often made from pseudo-equilibrium phases, frequently resulting in substantially over-estimated well yields. The methods developed in the present study to predict yields consist of extrapolating drawdown data from infinite acting radial flow periods or by fitting type curves of other conceptual models to the data, using diagnostic plots, inverse analysis and derivative analysis. Available drawdowns were determined by the positions of transition zones in crystalline rocks or thin-bedded consolidated sandstone/limestone layers (reservoir rocks). Aquifer dewatering effects were detected by type-curve matching of step-test data or by breaks in the drawdown curves constructed from hydraulic tests. Operational data were then used to confirm the predicted yields and compared to regional groundwater levels to determine seasonal variations in well yields. Such well yield estimates are needed by hydrogeologists and water engineers for the engineering design of water systems, but should be verified by the collection of long-term monitoring data.

  3. Reliable yields of public water-supply wells in the fractured-rock aquifers of central Maryland, USA

    Science.gov (United States)

    Hammond, Patrick A.

    2017-07-01

    Most studies of fractured-rock aquifers are about analytical models used for evaluating aquifer tests or numerical methods for describing groundwater flow, but there have been few investigations on how to estimate the reliable long-term drought yields of individual hard-rock wells. During the drought period of 1998 to 2002, many municipal water suppliers in the Piedmont/Blue Ridge areas of central Maryland (USA) had to institute water restrictions due to declining well yields. Previous estimates of the yields of those wells were commonly based on extrapolating drawdowns, measured during short-term single-well hydraulic pumping tests, to the first primary water-bearing fracture in a well. The extrapolations were often made from pseudo-equilibrium phases, frequently resulting in substantially over-estimated well yields. The methods developed in the present study to predict yields consist of extrapolating drawdown data from infinite acting radial flow periods or by fitting type curves of other conceptual models to the data, using diagnostic plots, inverse analysis and derivative analysis. Available drawdowns were determined by the positions of transition zones in crystalline rocks or thin-bedded consolidated sandstone/limestone layers (reservoir rocks). Aquifer dewatering effects were detected by type-curve matching of step-test data or by breaks in the drawdown curves constructed from hydraulic tests. Operational data were then used to confirm the predicted yields and compared to regional groundwater levels to determine seasonal variations in well yields. Such well yield estimates are needed by hydrogeologists and water engineers for the engineering design of water systems, but should be verified by the collection of long-term monitoring data.

  4. Paleomagnetic studies of volcanic rocks in Siberia and sedimentary rocks in Southern Alberta: From long-term geomagnetic field variations to age determinations

    Science.gov (United States)

    Blanco Acuna, Dunia

    Paleomagnetism is a fundamental tool to understand the ancient variations of Earth's magnetic field through time. Important applications to geochronology and paleography come from interpreting the variations of the planetary magnetic vector. This dissertation explores the different applications of paleomagnetism to uncover important characteristics of the paleointensity magnetic field during the Permo-Triassic boundary and the nature of the apparent polar wander path (APWP) of Siberia, and to create geochronological frameworks for kimberlites in the Siberian platform and for sediments at the Western Canada Sedimentary Basin. Detailed absolute paleointensity measurements from Permo-Triassic sills at the Siberian platform are studied to determine the existence of a low dipole field, which has been previously reported in the area. We found a mean virtual dipolar moment value of 6.01 +/- 1.45 x 1022 Am 2 which is over 50% higher than the results previously obtained by other authors. Diamondiferous kimberlite pipes are exposed across the north-central part of the Siberian platform. The age of the magmatic activity cannot be clearly determined from isotopic age data---this is the reason why new paleomagnetic poles from four kimberlite pipes are obtained to study their paleomagnetic age. On the basis of a comparison with the Siberian APWP, we estimate the age of the kimberlite magmatism. The acquired paleomagnetic ages span from the Early Silurian to the Middle Late Jurassic. Magnetostratigraphic analysis is used as a dating tool on three deep drilling cores that penetrate Santonian-Campanian strata in southern Alberta, Canada. Chrons 34n and 33r are clearly identified from the studied sections---providing a high-resolution age boundary that creates new age boundaries between adjacent stratigraphic units. In addition, normal polarity zones are observed within C33r, previously described as reverse polarity over its entire length. Siberian APWP contains long unresolved

  5. The Jettencave, Southern Harz Mountains, Germany: Geophysical observations and a structural model of a shallow cave in gypsum/anhydrite-bearing rocks

    Science.gov (United States)

    Kaufmann, Georg; Romanov, Douchko

    2017-12-01

    Gypsum and anhydrite are soluble rocks, where fissures and bedding partings can be enlarged with time by the dissolution of the mineral species through water. The selective enlargement results in sub-surface voids acting as preferential flow path for the drainage of the rock. With time, larger cavities develop, and a network of cave passages can evolve. If the enlarged cave voids are not too deep under the surface, geophysical measurements can be used to detect, identify and trace these structures. We have used gravity measurements (GRAV), electrical resistivity imaging (ERI), self-potential measurements (SP), electrical conductivity measurements (EC), and ground-penetrating radar (GPR) above the cave Jettenhöhle, a cave located in the southern Harz Mountains in Germany. The Jettencave is developed in the Hauptanhydrit formation of the Permian Zechstein sequence, characterised by large breakdown rooms and an exposed water table. The overburden of the cave is only around 10-15 m, and dolomitic rocks are located in close vicinity. We present results from our geophysical surveys in vicinity of the cave. We are able to identify the cave geometry from GRAV, ERI, and GPR measurements, which distinguish the local lithology of the Permian Zechstein rocks in the area. From the ERI and EC measurements, we derive information on the void volume in the soluble rocks. We finally present a three-dimensional structural model of the Jettencave and its surroundings, based on our geophysical results and the hydrological interpretation.

  6. Late Ediacaran volcano-sedimentary successions of southern Sinai (Egypt): tracing the evolution from late- to post-collisional volcanism and its relation to A-type rocks

    Science.gov (United States)

    Azer, Mokhles; Asimow, Paul; Obeid, Mohamed; Price, Jason; Wang, Max

    2017-04-01

    The Late Ediacaran post-collisional volcano-sedimentary successions exposed in southern Sinai (Egypt) represent the last stage of magmatic activity associated with assembly of the northernmost segment of the Neoproterozoic Arabian-Nubian Shield. To clarify the age and tempo of post-collisional activity, three volcanic successions from southern Sinai were selected for the present study: the Sahiya, Iqna Shar'a and Meknas volcanics. They comprise a series of intermediate to silicic volcanic flows and their pyroclastic rocks. New zircon U-Pb dating by SIMS of the lava flows from the three successions yielded ages ranging between ca. 619 to 600 Ma. Combined with field evidence and the geochemical data, the obtained SIMS zircon ages enable us to recognize two phases of volcanic activity in southern Sinai at ca. 619-615 Ma and 606-600 Ma. Both age groups were found within the more northerly volcanic successions at Iqna Shar'a and Meknas and in both these sequences the younger phase uncomformably overlies the older phase. Only the older ages, ca. 615-619 Ma, were found in the Sahiya volcanics, exposed at the southern tip of Sinai. The ages of the youngest calc-alkaline volcanics in the study areas are similar to or slightly younger than the earliest phases of alkaline volcanism in southern Sinai, indicating coeval extrusion of calc-alkalic and alkalic A-type rocks. This observation corroborates similar observations documenting cogenetic calc-alkalic and alkalic plutons in the surrounding areas in southern Sinai. Geochemically, the volcanic rocks of the three successions display large silica variations and are mostly medium- to high-K calc-alkaline rocks. The first phase, from ca. 619-615 Ma, observed in all three volcanic suites, comprises basaltic andesite, andesite and dacite, whereas the second phase, from ca. 606-600 Ma and observed only in the northern volcanic suites (Iqna Shar'a and Meknas), comprises dacite, rhyodacite and rhyolite. In the Sahiya succession basal

  7. Sedimentology, petrology, and gas potential of the Brallier Formation: upper Devonian turbidite facies of the Central and Southern Appalachians

    Energy Technology Data Exchange (ETDEWEB)

    Lundegard, P.D.; Samuels, N.D.; Pryor, W.A.

    1980-03-01

    The Upper Devonian Brallier Formation of the central and southern Appalachian basin is a regressive sequence of siltstone turbidites interbedded with mudstones, claystones, and shales. It reaches 1000 meters in thickness and overlies basinal mudrocks and underlies deltaic sandstones and mudrocks. Facies and paleocurrent analyses indicate differences between the depositional system of the Brallier Formation and those of modern submarine fans and ancient Alpine flysch-type sequences. The Brallier system is of finer grain size and lower flow intensity. In addition, the stratigraphic transition from turbidites to deltaic sediments is gradual and differs in its facies succession from the deposits of the proximal parts of modern submarine fans. Such features as massive and pebbly sandstones, conglomerates, debris flows, and massive slump structures are absent from this transition. Paleocurrents are uniformly to the west at right angles to basin isopach, which is atypical of ancient turbidite systems. This suggests that turbidity currents had multiple point sources. The petrography and paleocurrents of the Brallier Formation indicate an eastern source of sedimentary and low-grade metasedimentary rocks with modern relief and rainfall. The depositional system of the Brallier Formation is interpreted as a series of small ephemeral turbidite lobes of low flow intensity which coalesced in time to produce a laterally extensive wedge. The lobes were fed by deltas rather than submarine canyons or upper fan channel systems. This study shows that the present-day turbidite facies model, based mainly on modern submarine fans and ancient Alpine flysch-type sequences, does not adequately describe prodeltaic turbidite systems such as the Brallier Formation. Thickly bedded siltstone bundles are common features of the Brallier Formation and are probably its best gas reservoir facies, especially when fracture porosity is well developed.

  8. The Pyhäntaka formation, southern Finland: a sequence of metasandstones and metavolcanic rocks upon an intra-orogenic unconformity

    Directory of Open Access Journals (Sweden)

    Mikko Nironen

    2011-08-01

    Full Text Available Detrital zircon studies suggest that the few quartzite occurrences in southern Finland are younger than 1.87 Ga and express sedimentation after 1.89–1.87 Ga accretional deformation and metamorphism in the Svecofennian orogenic belt. Detailed field work in the high-grade metamorphic Pyhäntaka area allowed to distinguish an overturnedformation within metagraywackes (cordierite paragneisses and psammites. The Pyhäntaka formation has a maximum thickness of 1000 meters and consists of quartzite overlain by meta-arkose, metatuff, and metabasalt on top. An uncorformity, expressed by aweathering surface, separates the quartzite from underlying metagraywacke. The metavolcanic rocks within, stratigraphically underlying and overlying the Pyhäntaka formation are mostly basalts and basaltic andesites, but a felsic volcanic rock and dacitic fragments in volcaniclastic rocks imply bimodal affinity. The quartzite was deposited during a stable intra-orogenic period probably after accretion but before 1.83–1.80 Ga collisionaldeformation and metamorphism in the Svecofennian orogen. Rifting during the intraorogenic period and accumulation of variable material in the rift from nearby sources by fluvial processes is a viable scenario for deposition and preservation of the Pyhäntakaformation. Geochemical diagrams of the metavolcanic rocks show a scatter that is best explained by source heterogeneity and crustal contamination. Despite their (likely postaccretion setting the basaltic rocks show arc-type characteristics due to subduction-modified lithospheric mantle sources. Because of recycling, also the paragneisses in the Pyhäntaka area are geochemically similar in spite that they represent different tectonic settings. The use of elemental geochemistry alone appears to be insufficient for discriminatingtectonic settings of basalts or graywackes in the Svecofennian of southern Finland where accretion and post-accretion settings were largely obliterated by late

  9. Hominin responses to environmental changes during the Middle Pleistocene in central and southern Italy

    Directory of Open Access Journals (Sweden)

    R. Orain

    2013-03-01

    Full Text Available The palaeobotanical record of early Palaeolithic sites from Western Europe indicates that hominins settled in different kinds of environments. During the "mid-Pleistocene transition (MPT", from about 1 to 0.6 Ma, the transition from 41- to 100-ka dominant climatic oscillations, occurring within a long-term cooling trend, was associated with an aridity crisis which strongly modified the ecosystems. Starting from the MPT the more favourable climate of central and southern Italy provided propitious environmental conditions for long-term human occupations even during the glacial times. In fact, the human strategy of territory occupation was certainly driven by the availabilities of resources. Prehistoric sites such as Notarchirico (ca. 680–600 ka, La Pineta (ca. 600–620 ka, Guado San Nicola (ca. 380–350 ka or Ceprano (ca. 345–355 ka testify to a preferential occupation of the central and southern Apennines valleys during interglacial phases, while later interglacial occupations were oriented towards the coastal plains, as attested by the numerous settlements of the Roma Basin (ca. 300 ka. Faunal remains indicate that human subsistence behaviours benefited from a diversity of exploitable ecosystems, from semi-open to closed environments. In central and southern Italy, several palynological records have already illustrated the regional- and local-scale vegetation dynamic trends. During the Middle Pleistocene climate cycles, mixed mesophytic forests developed during the interglacial periods and withdrew in response to increasing aridity during the glacial episodes. New pollen data from the Boiano Basin (Molise, Italy attest to the evolution of vegetation and climate between MIS 13 and 9 (ca. 500 to 300 ka. In this basin the persistence of high edaphic humidity, even during the glacial phases, could have favoured the establishment of a refuge area for the arboreal flora and provided subsistence resources for the animal and hominin communities

  10. Hercynian late-post-tectonic granitic rocks from the Fornos de Algodres area (Northern Central Portugal)

    Science.gov (United States)

    Azevedo, M. R.; Nolan, J.

    1998-10-01

    The Fornos de Algodres Complex (FAC) comprises several intrusions of late-post-tectonic Hercynian granitic rocks ranging in composition from hornblende granodiorites and quartz monzodiorites, through coarse porphyritic biotite granites and two-mica granites (coarse-, medium- and fine-grained), to muscovite-rich leucogranites. Field and regional constraints show that the emplacement of this large, composite, batholithic complex post-dates the main Variscan regional deformation phases (D 1+D 2+D 3) and associated metamorphic events. Field, petrographic and geochemical data suggest a strong genetic relationship between most of the members of the FAC. However, their Rb-Sr and Sm-Nd isotopic signatures appear to rule out any genetic process involving a single homogeneous source and/or closed-system fractional crystallization of the same parental magma. A model involving hybridization of mantle-derived basaltic liquids with crustal anatectic melts followed by further contamination and fractional crystallization is proposed to explain the isotopic and geochemical variation trends defined by the FAC granitic rocks.

  11. Speciation on the rocks: integrated systematics of the Heteronotia spelea species complex (Gekkota; Reptilia from Western and Central Australia.

    Directory of Open Access Journals (Sweden)

    Mitzy Pepper

    Full Text Available The isolated uplands of the Australian arid zone are known to provide mesic refuges in an otherwise xeric landscape, and divergent lineages of largely arid zone taxa have persisted in these regions following the onset of Miocene aridification. Geckos of the genus Heteronotia are one such group, and have been the subject of many genetic studies, including H. spelea, a strongly banded form that occurs in the uplands of the Pilbara and Central Ranges regions of the Australian arid zone. Here we assess the systematics of these geckos based on detailed examination of morphological and genetic variation. The H. spelea species complex is a monophyletic lineage to the exclusion of the H. binoei and H. planiceps species complexes. Within the H. spelea complex, our previous studies based on mtDNA and nine nDNA loci found populations from the Central Ranges to be genetically divergent from Pilbara populations. Here we supplement our published molecular data with additional data gathered from central Australian samples. In the spirit of integrative species delimitation, we combine multi-locus, coalescent-based lineage delimitation with extensive morphological analyses to test species boundaries, and we describe the central populations as a new species, H. fasciolatus sp. nov. In addition, within the Pilbara there is strong genetic evidence for three lineages corresponding to northeastern (type, southern, and a large-bodied melanic population isolated in the northwest. Due to its genetic distinctiveness and extreme morphological divergence from all other Heteronotia, we describe the melanic form as a new species, H. atra sp. nov. The northeastern and southern Pilbara populations are morphologically indistinguishable with the exception of a morpho-type in the southeast that has a banding pattern resembling H. planiceps from the northern monsoonal tropics. Pending more extensive analyses, we therefore treat Pilbara H. spelea as a single species with

  12. U-Pb zircon and biostratigraphic data of high-pressure/low-temperature metamorphic rocks of the Talea Ori: tracking the Paleotethys suture in central Crete, Greece

    Science.gov (United States)

    Zulauf, G.; Dörr, W.; Krahl, J.; Lahaye, Y.; Chatzaras, V.; Xypolias, P.

    2016-10-01

    Inherited deformation microfabrics of detrital quartz grains and U-Pb (Laser ablation (LA)-ICPMS and ID TIMS) ages of detrital zircons separated from the Phyllite-Quartzite Unit s.l. of the Talea Ori, central Crete, suggest strikingly different source rocks. Albite gneiss of the lower Rogdia Beds includes Cambrian and Neoproterozoic rounded zircons with main U-Pb age peaks at 628 and 988 Ma. These and minor Paleoproterozoic and Archean peaks, together with the lack of Variscan-aged and Mesoproterozoic zircons, are similar to the age spectra obtained from the Phyllite-Quartzite Unit s.str. of the Peloponnesus and eastern Crete and from the Taurides. All of these zircons should be derived from the northeastern passive margin of Gondwana (Cimmeria). Metatuffites of the uppermost Rogdia Beds and metasandstone of Bali beach, on the other hand, include euhedral detrital zircons displaying a Variscan U-Pb age spectra at ca. 300 Ma with concordia ages at 291 ± 3, 300 ± 1 Ma (Rogdia) and 286 ± 3, 300 ± 3, 313 ± 2 Ma (Bali). Both types of metasediments and their zircons are similar to those of the pre-Alpine basement and overlying Tyros Beds of eastern Crete, revealing a provenance at the southern active margin of Laurasia. Thus, in central Crete the Paleotethys suture should be situated inside the Rogdia Beds. Magmatic zircons separated from a rhyolite boulder of the lower Achlada Beds yielded a concordant U-Pb zircon age at 242 ± 2 Ma placing a maximum age for the deposition of the (meta)conglomerate from which the boulder was collected. This age is compatible with an Olenekian-early Anisian age of the underlying Vasilikon marble suggested by new findings of the foraminifera Meandrospira aff. pusilla. Both the Achlada Beds and the Vasilikon marble can be attributed to the lower Tyros Beds of eastern Crete. The Alpine deformation led to a pervasive mylonitic foliation, which is affecting most of the studied rocks. This foliation results from D2 top

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

    Directory of Open Access Journals (Sweden)

    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

  14. Pluri-decadal (1955–2014) evolution of glacier–rock glacier transitional landforms in the central Andes of Chile (30–33° S)

    OpenAIRE

    Monnier, S.; Kinnard, C.

    2016-01-01

    This study deals with relationships between debris-covered glaciers and rock glaciers in the central Andes of Chile. Three glacier–rock glacier transitional landforms are investigated over the last decades in order to highlight and question the significance of their landscape evolution and dynamics. We use series of historical air photos and Geoeye satellite images together with common remote sensing operations including imagery orthorectification, digital elevation model generation, an...

  15. Old Age, Widows, and Rural Solitude in the Eighteenth Century Central-Southern Spain

    Directory of Open Access Journals (Sweden)

    Francisco GARCÍA GONZÁLEZ

    2016-12-01

    Full Text Available Current research about old age during the Ancient Regime in Spain is insufficient. And the same is the case with women, despite the large number of studies about gender and family history in the past decades. Taking, as a starting point, the analysis of widow women which became heads of households, this paper aims to know which specific characteristics had those households during their old age, composition, size, typology and the tendency to solitude; which activities and livelihood they had, paying attention to those differences as an expression of inequality; and which mechanisms and social reproduction strategies they followed to deal with the effects of aging. This paper is geografically focused in a wide rural area of central-southern Spain and aims to review the assumption that single and widow women in preindustrial age had subordinted lives. 

  16. Mixed nonlinear regression for modelling historical temperatures in Central-Southern Italy

    Science.gov (United States)

    Diodato, Nazzareno; Bellocchi, Gianni; Bertolin, Chiara; Camuffo, Dario

    2013-07-01

    This paper has exploited, for Central and Southern Italy (Mediterranean Sub-regional Area), an unprecedented historical dataset as an attempt to model seasonal (winter and summer) air temperatures in pre-instrumental time (back to 1500). Combining information derived from proxy-documentary data and large-scale simulation, a statistical downscaling approach in the form of mixed regression model was developed to adapt larger-scale estimations (regional component) to the sub-regional temperature pattern (local component). It interprets local temperature anomalies by means of monthly based Temperature Anomaly Scaled Index in the range -5 (very cold conditions in June) to 2 (very warm conditions). The modelled response agrees well with the independent data from the validation sample (Nash-Sutcliffe efficiency coefficient, >0.60). The advantage of the approach is not merely increased accuracy in estimation. Rather, it relies on the ability to extract (and exploit) the right information to replicate coherent temperature series in historical times.

  17. Behaviour of Southern sea lions in presence of killer whales during fishing operations in Central Chile

    Directory of Open Access Journals (Sweden)

    Luis Hückstädt

    2004-06-01

    Full Text Available The killer whale is an opportunistic top-predator of ecosystems worldwide and its diet varies locally and seasonally, which is reflected in diverse feeding behaviours associated with its prey. We report the occurrence of killer whales presumably predating on southern sea lions associated with the jack mackerel fishing fleet in central Chile. The presence of killer whales was recorded during 4 fishing sets. All sightings consisted of 3-5 individual pods of females and calves. The number of sea lions was not significantly affected by the presence of killer whales, but their behaviour was, by reducing the number of behavioural displays, as they stopped feeding and resting activities and stayed close to the hull of the vessel after net retrieval ended. We propose that killer whales could be using the fishery as an indirect source of prey to benefit from the aggregation of sea lions around the vessel, far away from land.

  18. Taxonomical, phytogeographical and ecological analysis of the salt marsh flora of Central and Southern Serbia

    Directory of Open Access Journals (Sweden)

    Zlatković, I.

    2014-12-01

    Full Text Available The floristic studies of salt marshes of Central and Southern Serbia in period 2000-2014 have shown presence of 333 taxa within 176 genera and 46 families. The phytogeographical structure is dominated by taxa with wide distribution (291 or 87.39%. The best represented chorological types are: Eurasian, Holarctic, Mediterranean-submediterranean and cosmopolitan. The analysis of representation of life forms has shown that salt marsh flora in this part of Serbia has therophytic character, with a significant participation of hemicryptophytes. Presence of a high number of threatened taxa, including some listed in “Red Book of Flora of Serbia, 1” as critically endangered (Cr plant taxa, indicates pronounced importance of these habitats for biodiversity conservation.

  19. Phosphorus Availability and Release Pattern from Activated Dolomite Phosphate Rock in Central Florida.

    Science.gov (United States)

    Mao, Xiaoyun; Lu, Qin; Mo, Wei; Xin, Xiaoping; Chen, Xian; He, Zhenli

    2017-06-14

    In this study, novel technology was developed to convert dolomite phosphate rock (DPR) into slow release P fertilizers. The DPR was powdered to <100 mesh and activated with organic molecules under optimal reaction conditions. As compared to original DPR, available P, estimated by water-soluble P released from the three DPRs activated with three types of organic molecules, increased by 6.86, 3.32, and 7.46 times, respectively. Phosphorus supply from the activated DPRs was greater than that of superphosphates (SP). Use of activated DPRs resulted in a significant increase in plant biomass of maize (Zea mays) and millet (Pennisetum glaucum) (succeeding crop), as compared to original DPR, and displayed better effectiveness than monoammonium phosphate or SP. The XRD and FTIR analyses showed that activation did not change the crystal structure of DPR, but the interactions between organic molecules and the P-bearing minerals stimulated P release from DPR.

  20. Wintering Sandhill Crane exposure to wind energy development in the central and southern Great Plains, USA

    Science.gov (United States)

    Pearse, Aaron T.; Brandt, David; Krapu, Gary

    2016-01-01

    Numerous wind energy projects have been constructed in the central and southern Great Plains, USA, the main wintering area for midcontinental Sandhill Cranes (Grus canadensis). In an initial assessment of the potential risks of wind towers to cranes, we estimated spatial overlap, investigated potential avoidance behavior, and determined the habitat associations of cranes. We used data from cranes marked with platform transmitting terminals (PTTs) with and without global positioning system (GPS) capabilities. We estimated the wintering distributions of PTT-marked cranes prior to the construction of wind towers, which we compared with current tower locations. Based on this analysis, we found 7% spatial overlap between the distributions of cranes and towers. When we looked at individually marked cranes, we found that 52% would have occurred within 10 km of a tower at some point during winter. Using data from cranes marked after tower construction, we found a potential indication of avoidance behavior, whereby GPS-marked cranes generally used areas slightly more distant from existing wind towers than would be expected by chance. Results from a habitat selection model suggested that distances between crane locations and towers may have been driven more by habitat selection than by avoidance, as most wind towers were constructed in locations not often selected by wintering cranes. Our findings of modest regional overlap and that few towers have been placed in preferred crane habitat suggest that the current distribution of wind towers may be of low risk to the continued persistence of wintering midcontinental Sandhill Cranes in the central and southern Great Plains.

  1. Oscillations and trends of river discharge in the southern Central Andes and linkages with climate variability

    Science.gov (United States)

    Castino, Fabiana; Bookhagen, Bodo; Strecker, Manfred R.

    2017-12-01

    This study analyzes the discharge variability of small to medium drainage basins (102-104 km2) in the southern Central Andes of NW Argentina. The Hilbert-Huang Transform (HHT) was applied to evaluate non-stationary oscillatory modes of variability and trends, based on four time series of monthly-normalized discharge anomaly between 1940 and 2015. Statistically significant trends reveal increasing discharge during the past decades and document an intensification of the hydrological cycle during this period. An Ensemble Empirical Mode Decomposition (EEMD) analysis revealed that discharge variability in this region can be best described by five quasi-periodic statistically significant oscillatory modes, with mean periods varying from 1 to ∼20 y. Moreover, we show that discharge variability is most likely linked to the phases of the Pacific Decadal Oscillation (PDO) at multi-decadal timescales (∼20 y) and, to a lesser degree, to the Tropical South Atlantic SST anomaly (TSA) variability at shorter timescales (∼2-5 y). Previous studies highlighted a rapid increase in discharge in the southern Central Andes during the 1970s, inferred to have been associated with the global 1976-77 climate shift. Our results suggest that the rapid discharge increase in the NW Argentine Andes coincides with the periodic enhancement of discharge, which is mainly linked to a negative to positive transition of the PDO phase and TSA variability associated with a long-term increasing trend. We therefore suggest that variations in discharge in this region are largely driven by both natural variability and the effects of global climate change. We furthermore posit that the links between atmospheric and hydrologic processes result from a combination of forcings that operate on different spatiotemporal scales.

  2. Columnar aerosol optical properties at AERONET sites in northern, central and southern Mexico

    Science.gov (United States)

    Carabali, Giovanni; Estévez, Hector; Florean-Cruz, Claudia; Navarro-Medina, Abigail; Valdés-Barrón, Mauro; Bonifaz-Alfonzo, Roberto; Riveros-Rosas, David; Velasco-Herrera, Víctor; Vázquez-Gálvez, Felipe

    2017-04-01

    The column-integrated optical properties of aerosol in the north, central and southern Mexico were investigated based on Sun/sky radiometer measurements made at Aerosol Robotic Network (AERONET) sites. Characterization of aerosol properties in these Mexico regions is important due to natural and anthropogenic significant events that occurred: dust storms from Sonora desert, biomass burning from south forest areas and urban/industrial from Mexico City due to the increases in fossil fuel combustion. Some cities in northern Mexico located near desert areas are affected by the dust from Sonora and Chihuahua deserts. These particles are suspended in the atmosphere due to strong wind activity that creates dust storms. In the central part of the Mexican territory, urban air pollution is one of the biggest problems. Mexico City is the most important urban area that face seriously environmental problem generated by daily anthropogenic emissions from activities of some 21 million people and the vast amount of industry. On the other hand, biomass burning in the Yucatan Peninsula, Southern Mexico, and Guatemala is an important source of anthropogenic aerosol in the troposphere (Crutzen and Andrade, 1990). The pollution from these fires affects air quality locally and is transported over the Gulf of Mexico to the United States (Wang et al., 2006). The aim of this work is to study the optical properties of different types of aerosols by analyzing a 5-year (2005-2010) data set from AErosol RObotic NETwork (AERONET). Time series of Angstrom exponent (α) and aerosol optical depth (τ) in 7 wavelengths from 340 to 1020 nm are shown. Additionally, a graphical framework to classify aerosol properties using direct sun-photometer observations in the different regions of Mexico is presented. That aerosol classification was made by applying the method described by Gobbi et al (2007), which relies on the combined analysis of α and its spectral curvature δα.

  3. Food limitation of sea lion pups and the decline of forage off central and southern California.

    Science.gov (United States)

    McClatchie, Sam; Field, John; Thompson, Andrew R; Gerrodette, Tim; Lowry, Mark; Fiedler, Paul C; Watson, William; Nieto, Karen M; Vetter, Russell D

    2016-03-01

    California sea lions increased from approximately 50 000 to 340 000 animals in the last 40 years, and their pups are starving and stranding on beaches in southern California, raising questions about the adequacy of their food supply. We investigated whether the declining sea lion pup weight at San Miguel rookery was associated with changes in abundance and quality of sardine, anchovy, rockfish and market squid forage. In the last decade off central California, where breeding female sea lions from San Miguel rookery feed, sardine and anchovy greatly decreased in biomass, whereas market squid and rockfish abundance increased. Pup weights fell as forage food quality declined associated with changes in the relative abundances of forage species. A model explained 67% of the variance in pup weights using forage from central and southern California and 81% of the variance in pup weights using forage from the female sea lion foraging range. A shift from high to poor quality forage for breeding females results in food limitation of the pups, ultimately flooding animal rescue centres with starving sea lion pups. Our study is unusual in using a long-term, fishery-independent dataset to directly address an important consequence of forage decline on the productivity of a large marine predator. Whether forage declines are environmentally driven, are due to a combination of environmental drivers and fishing removals, or are due to density-dependent interactions between forage and sea lions is uncertain. However, declining forage abundance and quality was coherent over a large area (32.5-38° N) for a decade, suggesting that trends in forage are environmentally driven.

  4. Importance of Rocks and Their Weathering Products on Groundwater Quality in Central-East Cameroon

    Directory of Open Access Journals (Sweden)

    Merlin Gountié Dedzo

    2017-04-01

    Full Text Available The present work highlights the influence of lithology on water quality in Méiganga and its surroundings. The main geological formations in this region include gneiss, granite and amphibolite. The soils developed on these rocks are of ABC type, which are acidic to slightly acidic. Electrical conductivity (EC, organic matter, total nitrogen, nitrate-nitrogen, sulfate, chloride, phosphorus and exchangeable base values were low to very low in the soil samples. Groundwater samples were investigated for their physicochemical characteristics. The wide ranges of EC values (15.1–436 µS/cm and total dissolved solids (9–249 mg/L revealed the heterogeneous distribution of hydrochemical processes within the groundwater of the area. The relative abundance of major dissolved species (mg/L was Ca2+ > Na+ > Mg2+ > K+ for cations and HCO3− >> NO3− > Cl− > SO42− for anions. All the groundwater samples were soft, with total hardness values (2.54–136.65 mg/L below the maximum permissible limits of the World Health Organization (WHO guideline. The majority of water samples (67% were classified as mixed CaMg-HCO3 type. Alkaline earth metal contents dominated those of alkali metals in 66.66% of samples. Thus, for the studied groundwater, Mg2+ and Ca2+ ion adsorption by clay minerals was almost nonexistent; this implies their release into the solution, which accounts for their high concentrations compared to alkali metals. Ion geochemistry revealed that water-rock interactions (silicate weathering and ion exchange processes regulated the groundwater chemistry. One water sample points towards the evaporation domain of this diagram, indicating that groundwater probably does not originate from a deeper system. Kaolinite is the most stable secondary phase in the waters in the study area, in accordance with the geochemical process of monosiallitization, which predominated in the humid tropical zone.

  5. Paleomagnetic and AMS study of Permian and Triassic rocks from the Hronic Nappe and Paleogene rocks from the Central Carpathian Paleogene Basin, Western Carpathians

    Science.gov (United States)

    Márton, Emö; Madzin, Jozef; Bučová, Jana; Grabowski, Jacek; Plašienka, Dušan; Aubrecht, Roman

    2017-04-01

    The Hronic (Choč) units form the highest cover nappe system of the Central Western Carpathians which was emplaced over the Fatric (Krížna) nappe system during the Late Cretaceous. The Permian (red beds and lava flows) and Triassic (sediments) rocks, the main targets of our study, were affected only by diagenetic or very low-grade, burial-related recrystallization and were tilted and transported together. The pre-late Cretaceous sequence is overlapped by Paleogene mainly flysch sequences. Three laboratories (Bratislava, Budapest and Warsaw) were involved in standard paleomagnetic processing and AMS measurements of the samples, while Curie-points were determined in Budapest. The site/locality mean paleomagnetic directions obtained were significantly different from the local direction of the present Earth magnetic field, indicating the long term stability of the paleomagnetic signal. The magnetic fabrics varied from un-oriented to dominantly schistose with well-defined lineations. The latter were normally subhorizontal, although subvertical maxima also occurred among the Triassic sediments. Shallow inclinations, after tilt corrections, suggest near-equatorial position for most of the Permian and Lower Triassic, while around 20°N for the Middle-Upper Triassic localities. The paleomagnetic declinations are interpreted in terms of CW tectonic rotations, which are normally larger for the Permian than for the Triassic samples, although there are some differences within the same age groups. This may be attributed to differential movements during nappe emplacement or subsequent tectonic disturbances. For two localities from the Paleogene cover sequence of the Hronic units, close to the main sampling area (Low Tatra Mts) of the present study documented fairly large CCW rotations, thus obtained additional evidence for the general CCW rotation of the Central Western Carpathians during the Cenozoic. Thus, we conclude that the Cenozoic CCW rotation was pre-dated by large CW

  6. A rock- and paleomagnetic study of a Holocene lava flow in Central Mexico

    NARCIS (Netherlands)

    Vlag, P.; Alva-Valdivia, L.; Boer, C.B. de; Gonzalez, S.; Urrutia-Fucugauchi, J.

    1999-01-01

    Magnetic measurements of the Tres Cruces lava flow (ca. 8500 years BP, Central Mexico) show the presence of two remanence carriers, a Ti-rich titanomagnetite with a Curie temperature between 350 and 400 °C and a Ti-poor magnetite with a Curie temperature close to 580°C. Magnetic changes after

  7. A 10,300-year-old permafrost core from the active rock glacier Lazaun, southern Ötztal Alps (South Tyrol, northern Italy)

    Science.gov (United States)

    Krainer, Karl; Bressan, David; Dietre, Benjamin; Haas, Jean Nicolas; Hajdas, Irka; Lang, Kathrin; Mair, Volkmar; Nickus, Ulrike; Reidl, Daniel; Thies, Hansjörg; Tonidandel, David

    2015-03-01

    Two cores were drilled on rock glacier Lazaun in the southern Ötztal Alps (N Italy). The average ice content of core Lazaun I is 43 vol.% and of core Lazaun II is 22 vol.%. Radiocarbon dating of plant macrofossil remains of core Lazaun I yielded ages ranging from 8960 cal yr BP at a depth of ca. 23.5 m to 2240 cal yr BP at a depth of 2.8 m, indicating that the ice near the base is approximately 10,300 yr old. The rock glacier was intact since that time and the ice persisted even during warm periods of the Holocene. An ice-free debris layer between 16.8 and 14.7 m separates the rock glacier into two frozen bodies. Inclinometer measurements indicate that both frozen bodies are active and that deformation occurs within a shear horizon at a depth of 20-25 m at the base of the lower frozen body and to a minor extent at a depth of approximately 14 m at the base of the upper frozen body. The ice-free debris layer in the middle of the Lazaun rock glacier indicates a more than five centennial long drought period, which dates to about 4300-3740 cal yr BP.

  8. Widespread Neogene and Quaternary Volcanism on Central Kerguelen Plateau, Southern Indian Ocean

    Science.gov (United States)

    Duncan, R. A.; Falloon, T.; Quilty, P. G.; Coffin, M. F.

    2016-12-01

    We report new age determinations and compositions for rocks from 18 dredge hauls collected from eight submarine areas across Central Kerguelen Plateau (CKP). Sea knolls and volcanic fields with multiple small cones were targeted over a 125,000 km2 region that includes Heard and McDonald islands. Large early Miocene (16-22 Ma) sea knolls rise from the western margin of the CKP and are part of a NNW-SSE line of volcanic centers that lie between Îles Kerguelen and Heard and McDonald islands. A second group of large sea knolls is aligned E-W across the center of this region. We see evidence of much younger activity (5 Ma to present) in volcanic fields to the north of, and up to 300 km NE of Heard Island. Compositions include basanite, basalt, and trachybasalt, that are broadly similar to plateau lava flows from nearby Ocean Drilling Program (ODP) Site 1138, lower Miocene lavas at Îles Kerguelen, dredged rocks from the early Miocene sea knolls, and Big Ben lavas from Heard Island. Geochemical data indicate decreasing fractions of mantle source melting with time. The western line of sea knolls has been related to hotspot activity now underlying the Heard Island area. In view of the now recognized much larger area of young volcanic activity, we propose that a broad region of CKP became volcanically active in Neogene time due to incubation of plume material at the base of the relatively stationary overlying plateau. The presence of pre-existing crustal faults promotes access for melts from the Heard mantle plume to rise to the surface.

  9. Paleomagnetism, rock magnetism and opaque mineralogy of iron ore deposits from southern Mexico and their implications for quantitative modelling of magnetometric data

    Energy Technology Data Exchange (ETDEWEB)

    Alva-Valdivia, L.M.; Fucugauchi, Urrutia, J.; Bohnel, H.; Moran Zenteno, D.J. (Universidad Nacional Autonoma de Mexico, Mexico City (Mexico))

    1990-06-01

    Paleomagnetism, Rock Magnetism and Opaque Mineralogy of Iron Ore Deposits from Southern Mexico and Their Implications for Quantitative Modelling of Magnetometric Data. The tectonic history of the Pacific continental margin is critical for understanding their mineral deposits. The margin presents intrusive and volcanic activity characteristic of magmatic arcs of subduction zones, which are genetically related with deposits of Cu, Fe, Mo, Au, and Ag. Although the tectonic history has been complex, involving oblique plate subduction, lateral movements, accretion of magmatic arcs and oceanic plateaux, and lateral displacements of major blocks, the mineral deposits are spatially distributed along elongated belts that roughly follow the margin. The authors have conducted paleomagnetic, rock magnetic, and petrological studies of the iron ore deposits to investigate genesis, magnetic mineralogy, stratigraphic relationships, metamorphism, and applications on quantitative modelling of magnetometric data. The remanent magnetization and susceptibility data are necessary for interpretation of magnetic anomalies. The results permit a comparison of the mineral deposits along the continental margin.

  10. Temporal evolution of the Western and Central volcanism of the Aeolian Island Arc (Italy, southern Tyrhhenian Sea)

    Science.gov (United States)

    Leocat, E.; Gillot, P.-Y.; Peccerillo, A.

    2009-04-01

    The Aeolian Archipelago is a volcanic arc in the Southern Tyrrhenian Sea located on the continental margin of the Calabro-Peloritan basement. The Aeolian volcanism occurs in a very complex geodynamic setting linked to the convergence of the European and African plates. For that reason, it is strongly related to regional tectonic lineaments, such as the NW-SE trending Tindari-Letojani (TL) fault. The archipelago consists of seven main islands and several seamounts, which extend around the Marsili Basin, forming a ring-like shape, typical for an island arc. While the seamounts began their activities around 1 Ma , the emerged part is active since about 400 ka. The magmatic products of the whole arc range from typical island arc calc-alkaline (CA) and shoshonitic series, to slightly silica undersaturated potassic alkaline series that are typical of post-collisional settings. Furthermore, the TL fault, along which the Lipari and Vulcano islands are developed, separates a calc-alkaline western sector (Alicudi, Filicudi and Salina islands) from the calc-alkaline to potassic eastern system (Panarea and Stromboli islands) (Peccerillo,1999). This makes of the Aeolian Islands a complex volcanism, with a still controversial origin. In this context, the aim of this work is to constrain the sources and spatio-temporal evolution of this magmatism. We present here new K-Ar ages based on the accurate Cassignol-Gillot technique devoted to the dating of very young rocks (Gillot et Cornette, 1986). These geochronological data were used together with new geochemical data on the same samples. In this study, we attempt to understand the origin of those magmatic events and the relationship between the deep processes and the shallow structures. Our results allow us to define specific periods of very quick geomechemical changes. In the case of Filicudi island, the first rocks range in composition from CA basalts to andesites. This period ended with the edification of the Mte Guardia at 189

  11. The Origin of the Chinese Central Tianshan Block in the Southern Central Asian Orogenic Belt: Evidence from Detrital Zircon Study

    Science.gov (United States)

    Huang, Z.; Long, X.; Yuan, C.

    2016-12-01

    The Chinese Central Tianshan Block (CTB) is one of the oldest continental fragments in the southern Central Asian Orogenic Belt (CAOB). Although it is vital for understanding the evolution of the CAOB, its origin has been poorly studied. The CTB was previously suggested to have been originated from the North China, the South China, the Tarim cratons or the East European Craton (Baltica). A total of 165 concordant U-Pb and Hf isotopic analyses of detrital zircon are obtained from three meta-sediments in the CTB, including one meta-sandstone from Xingxingxia formation and one meta-sandstone as well as one quartzite from Kawabulake formation. Detrital zircon grains from the Xingxingxia and Kawabulake formations are dominated by respective youngest age populations at 1002 Ma and 930-960 Ma, providing constraints on the maximum depositional ages for these two formations. Zircon grains from the meta-sediments have very similar age distributions, with two dominant peaks at 0.93-1.0 Ga and 1.0-1.6 Ga and a minor peak at 2.3-2.7 Ga. They have similar Hf isotopic signatures, suggesting that the meta-sediments in the CTB share similar sedimentary provenance. The early Neoproterozoic detrital zircon grains are mainly local-derived, whereas the Paleo-Mesoproterozoic grains are both autochthonous and allochthonous. The occurrence of these Mesoproterozoic and Neoproterozoic zircon grains are coincident with the Nuna breakup and the Rodinia assembly. This suggests that the CTB might experience the tectonic switching of the Nuna to the Rodinia. The distinct Meso-Neoproterozoic age patterns and Hf isotopic compositions of these detrital grains from the CTB and the surrounding blocks indicate that the CTB was not located close to the North China, the South China or the Tarim cratons in Precambrian. Our new data suggest that the CTB was most likely once a part of the East European Craton before the Neoproterozoic. This study was supported by National Basic Research Program of China

  12. 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

    , and molybdenum) were 41% high, 36% moderate, and 23% low. In the Southern Sierra study unit, 32, 34, and 34% of the primary aquifer had high, moderate, and low RCs of inorganic constituents with health-based benchmarks (primarily arsenic, uranium, fluoride, boron, and nitrate). The high aquifer-scale proportions for inorganic constituents with non-health-based benchmarks were 14, 34, and 24% for the Tahoe-Martis, Central Sierra, and Southern Sierra study units, respectively, and the primary constituent was manganese for all three study units. Organic constituents with health-based benchmarks were not present at high RCs in the primary aquifers of the Central Sierra and Southern Sierra study units, and were present at high RCs in only 1% of the Tahoe-Martis study unit. Moderate aquifer-scale proportions for organic constituents were 10%: the trihalomethane chloroform in the Tahoe-Martis study unit; chloroform and the herbicide simazine in the Central Sierra study unit; and chloroform, simazine, the herbicide atrazine, and the solvent perchloroethene in the Southern Sierra study unit. The second component of this study, the understanding assessment, identified the natural and human factors that may have affected groundwater quality in the three study units by evaluating statistical correlations between water-quality constituents and potential explanatory factors. The potential explanatory factors evaluated were land use, septic tank density, climate, relative position in the regional flow system, aquifer lithology, geographic location, well depth and depth to the top of the screened or open interval in the well, groundwater age distribution, pH, and dissolved oxygen concentration. Results of the statistical evaluations were used to explain the occurrence and distribution of constituents in the study units. Aquifer lithology (granitic, metamorphic, sedimentary, or volcanic rocks), groundwater age distribution [modern (recharged since 1952), pre-modern (recharged before

  13. Stand structure of a primate rich rainforest region in the central Western Ghats of southern India

    Directory of Open Access Journals (Sweden)

    K. Roy

    2010-06-01

    Full Text Available The Western Ghats of southern India are one of the most important biodiversity regions in the world, not only due to their faunal diversity and abundance but also due to different habitat types, floral diversity and the presence of several endemic plant species. The rainforests in the central Western Ghats are inhabited by several primate species. We investigated the vegetation pattern and tree species occupancy of one of the prime primate habitats in the central Western Ghats. Lion-tailed Macaque (Macaca silenus, Bonnet Macaque (Macaca radiata, Hanuman Langur (Semnopithecus entellus achates and Malabar Slender Loris (Loris lydekkerianus malabaricus inhabit the study area. We studied the density, dominance, frequency and Importance Value Index (IVI of different tree species, using the belt transect method on randomly selected plots covering 4.1ha. We found that all the plant species that emerged to be the most dominant species with high IVI in the forest were also used by the diurnal primates for foraging. Knema attenuata and Syzygium gardneri were found to be the ‘keystone’ species. Since the forests of the study area do not come under the ‘protected area network’ for wildlife, the data obtained during this study will be helpful in the forestry management practices with a view for wildlife conservation of the region.

  14. Zircon Geochemistry of Granitic Rocks from Ong Valley and Moraine Canyon in the Central Transantarctic Mountains, Antarctica

    Science.gov (United States)

    Liu, J.; Morgan, D. J.; Claiborne, L. L.; Padilla, A. J.; Edwards, K. L.; Putkonen, J.; Bibby, T.; Cribb, J. W.

    2015-12-01

    A number of granitic rocks exposed throughout the Central Transantarctic Mountains (CTAM) are thought to have been generated during and following the Ross Orogeny (late Cambrian to early Ordovician). Understanding the origin of these rocks can help improve our understanding of the tectonic events responsible for the suturing of Gondwana. In this study, we use zircon as a tool to investigate the magmatic origins and evolution of CTAM granites. Zircon has a low solubility in almost all melt and fluid compositions, is stable and resistant to alteration at Earth's surface, and is physically durable during transport. These features enable it to survive many crustal processes during which most other minerals are destroyed, thus preserving an important geochemical record of its crystallizing environments. We collected granitic samples from two sites in the CTAM: Ong Valley (157.5°E, 83.25°S), where the Hope Granite is exposed intruded into pre-Cambrian gneisses, and Moraine Canyon (157.55°W, 86.1°S), where bedrock exposure is dominated by a silicic porphyry of the Wyatt Formation. Our zircon U-Pb data, collected in-situ by laser ablation (LA) ICP-MS, suggests that the Hope Granite has a mean weighted crystallization age of 582 ± 23 Ma (2σ; n=26), older than the published age (510 ± 9 Ma, 1σ; whole-rock Rb-Sr isochrons; Faure & Mensing, 2010). The spread in individual zircon ages is consistent with previous estimates for the duration of intrusion (~20 Myr) of the Hope Granite. Published ages for Wyatt Fm rocks range from ~525 to ~800 Ma, but their origin is uncertain. We will analyze zircons from the Wyatt porphyry for U-Pb isotopes (by LA-ICP-MS) to better constrain its age. In addition, we will obtain trace element compositions of zircons from both intrusions to investigate their magmatic origins. This will allow us to explore potential geochemical connections between the intrusions, and may yield additional insight into the tectonic events involved in the Ross

  15. Landsliding generated by thermomechanical interactions between rock columns and wedging blocks: Study case from the Larzac Plateau (Southern France)

    Science.gov (United States)

    Taboada, Alfredo; Ginouvez, Hadrien; Renouf, Mathieu; Azemard, Pierre

    2017-06-01

    The Larzac Plateau is delimited by vertical cliffs whose geometry is controlled by vertical joints. Cliff's erosion involves landslides initiated by incremental enlargement of joints that progressively detach rock columns at very low velocities (1.2 mm/yr). We find that enlargement of joints is linked to intraseasonal thermal cycles ranging between 2-15 days in relation with dilation/contraction of rock blocks trapped inside the joints. The mechanism involves two successive stages in which blocks create a wedging and a ratcheting effect on the rock column. Wedging is associated with compressional forces acting on the rock column, resulting from temperature increase and dilation of the shallow rocks. Ratcheting is associated with downward displacement of blocks by gravity to a new equilibrium position, resulting from temperature decrease and contraction of shallow rocks. The displacement vector in a thermal cycle is split into a plastic and a thermal component; plastic displacements range between 10 — 200 μm according to the seasons, and are absorbed along a shear plane dipping 40° beneath the rock column: they are largest during autumn and winter, minor during spring and negligible in summer. This deformation mechanism is termed thermomechanical creep as permanent deformations are associated to mechanical forces induced by short-term thermal cycles.

  16. Dynamics of rock glaciers and debris-covered glaciers in the Central Chilean Andes over the last 50 years

    Science.gov (United States)

    Bodin, Xavier; Brenning, Alexander; Rojas Marchini, Fernanda

    2010-05-01

    In the semiarid Central Andes of Chile at 33.5°S., mountain permafrost is widely present above 3500-4000 m asl, especially in the form of rock glaciers, which often coexist with glaciers and debris-covered glaciers. This peculiar configuration of the cryosphere involves complex and poorly known responses of its components to climate change. Our study area in the Laguna Negra catchment is part of a watershed that provides up to two-thirds of the drinking water supplies to Chile's capital Santiago (5.5 million inhabitants) during the dry summer months. The 35 km² watershed contains 2.3 km² of uncovered glaciers, 0.9 km² of debris-covered glacier area and 4.3 km² of rock glaciers, and hosts the longest series of glacier mass balance measurement in Chile (Echaurren Norte glacier). Using orthorectified aerial photographs of 1956 and 1996 and a high resolution satellite image of 2008, we mapped the geometric changes that affected the glacier and the debris-covered glacier of the Punta Negra sub-catchment during the last 50 years. Surface displacements and volume changes were estimated based on 1956 and 1996 digital elevation models (DEMs), and the total loss of water equivalent in the catchment was quantified. At a shorter time scale, rock glaciers and a debris-covered glacier are being monitored since 2004, providing insights into their kinematics and near-surface thermal regime. The orthophotos reveal a 44.7% reduction of the uncovered glacier area between 1955 and 1996, and only small surface changes between 1996 and 2008. The volume reduction of both uncovered and debris-covered glaciers is estimated at at least 3.9 million m3 water equivalent between 1955 and 1996. The second noticeable change is the growth of the thermokarst areas on the debris-covered glacier, with the formation of new and the widening and deepening of existing melt-out depressions between 1955 and 2008. The thermal monitoring revealed that, in 2003/04, the mean annual ground surface

  17. Hydrographical features of the southern and central Bay of Bengal during the transition period between winter and summer

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, L.V.G.; Jayaraman, R.

    During Feb.-Mar. 1963, INS KISTNA has carried out its 6th and 7th oceanographic cruises in the southern and central parts of Bay of Bengal under the Indian Programme of IIOE. With the physical oceanographic data collected in these cruises...

  18. Geochronology and geochemistry of Permian bimodal volcanic rocks from central Inner Mongolia, China: Implications for the late Palaeozoic tectonic evolution of the south-eastern Central Asian Orogenic Belt

    Science.gov (United States)

    Zhang, Zhicheng; Chen, Yan; Li, Ke; Li, Jianfeng; Yang, Jinfu; Qian, Xiaoyan

    2017-03-01

    Zircon U-Pb ages, geochemical data and Sr-Nd isotopic data are presented for volcanic rocks from the lower Permian Dashizhai Formation. These rocks are widely distributed in the south-eastern Central Asian Orogenic Belt in central Inner Mongolia, China. The volcanic rocks mainly consist of basaltic andesite and rhyolite, subordinate dacite and local andesite, and exhibit bimodal geochemical features. The results of zircon U-Pb dating indicate that the volcanic rocks formed during the early Permian (292-279 Ma). The mafic volcanic rocks belong to low-K tholeiitic to medium-K calc-alkaline series. These mafic volcanic rocks are also characterised by moderately enriched light rare earth element (LREE) patterns; high abundances of Th, U, Zr and Hf; negative Nb, Ta and Ti anomalies; initial 87Sr/86Sr ratios of 0.70514-0.70623; and positive εNd(t) values (+1.9 to +3.8). These features indicate that the mafic volcanic rocks were likely derived from the high-percentage partial melting of subduction-related metasomatised asthenospheric mantle. The felsic rocks show an A-type affinity, with enrichments in alkalis, Th, U and LREEs. The felsic rocks are depleted in Ba, Sr, Nb, Ta and Ti and exhibit moderately LREE-enriched patterns (LaN/YbN = 2.09-6.45) and strongly negative Eu anomalies (Eu/Eu∗ = 0.04-0.25). These features, along with the positive εNd(t) values (+2.6 to +7.7) and young TDM2 ages (TDM2 = 435-916 Ma), indicate that the felsic rocks were likely derived from a juvenile crustal source that mainly consisted of juvenile mid-ocean ridge basalt-related rocks. The volcanic association in this study and in previously published work widely distributed in central Inner Mongolia. The observations in this study suggest that the lower Permian volcanic rocks formed in an identical tectonic environment. The regional geological data indicate that the bimodal volcanic rocks from the lower Permian Dashizhai Formation in the study area formed in an extensional setting that was

  19. Effects of forest fires in southern and central of Zabaykal region

    Directory of Open Access Journals (Sweden)

    L. V. Buryak

    2016-12-01

    Full Text Available The fire frequency situation in Zabaykal region from 1964 to 2015 is evaluated and discussed in the paper. The main reasons of decadal increase of fire numbers and the area burned are revealed. The main reasons of high fire frequency and the increase of fire activity in the last decades are shown. The characteristics of the weather conditions in the years of high fire frequency are presented. Fire activity was found to increase not only because of the droughts in the last decades but also due to forest disturbances in Zabaykalsky Krai by illegal logging. Based on the data from 170 sample sites laid out with the use of satellite images, forest inventory data and results of ground sample transects, the impact of the wildfires of different type, form and severity on tree mortality in the light-coniferous forests was estimated, as well as the amount of tree regeneration in the forest areas disturbed by fires, logged sites (both burned and unburned, and sites burned repeatedly was evaluated. Wildfires in the Zabaykal region were found to be strong ecological factor influencing on the probability of existence of many forest ecosystems. In case of further climate warming and repeated fires, the part of the forests may transform to the non forest areas. The steppification of the burned sites in the southern forest-steppe regions and in the low parts of the southern slopes at the border with steppe landscapes as well as desertification in the central parts of the region and swamping of burned sites located in the wet soils are observed. Wind and water soil erosion happens at the large burned sites.

  20. Sustainable yield of the Colle Quartara carbonate aquifer in the Southern Lepini Mountains (Central Italy

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    Giovanni Conte

    2016-10-01

    Full Text Available The present research is aimed to contribute to the groundwater resource sustainable management of a carbonate aquifer in a test area of the Lepini Mountains (Central Italy. This aquifer constitutes a major exploited groundwater body of central Apennines. At regional scale, the hydrogeological features of the Lepini hydrostructure are well known. The present study focuses on a portion of the Lepini Mountains where important tapping-works for drinking water supply are in activity (about 1.2 m3/s. New investigations were carried out including: meteo-climatic analysis, spring discharge and hydrometric time series processing, pumping test result interpretation. In addition, a detailed lithostratigraphical and structural survey of a portion of the Lepini hydrostructure at 1:10,000 scale was performed also examining the dense network of discontinuities affecting the carbonate aquifer. Extensional Plio-Pleistocene tectonic activity displaced the carbonate rock sequence under the Pontina Plain, where the carbonate aquifer is confined. The investigation results have allowed the reconstruction of the hydrogeological conceptual model of the studied portion of carbonate massif. Given the scale of the study and the results of the investigation, the carbonate aquifer can be treated as an equivalent porous medium, and the simplified numerical model of the aquifer was constructed with the code MODFLOW-2005. The numerical model, still now under continuous implementation, produced first results on the current withdrawal sustainability, allowing evaluation of possible alternative exploitation scenarios of the carbonate aquifer also considering the probably not significant flow exchanges with the Pontina Plain aquifer.

  1. Paleomagnetic correlation of ignimbrites along the southern margin of the central Snake River Plain, Yellowstone hotspot

    Science.gov (United States)

    Finn, D. R.; Coe, R. S.; Spinardi, F.; Reichow, M. K.; Knott, T.; McDonnell, L.; Cunningham, D.; Branney, M.

    2011-12-01

    Mid-late Miocene explosive volcanism associated with the Yellowstone hotspot occurred in the central Snake River Plain, for example at the 12.5-11.3 Ma Bruneau-Jarbidge and 10-8.6 Ma Twin Falls eruptive centres. The volcanism was characterized by high-temperature rhyolitic caldera-forming super-eruptions, some exceeding 450 km3. To determine the number and scales and of these giant eruptions we are investigating successions of outflow ignimbrites at the southern and northern margins of the plain. The ignimbrites are exposed discontinuously in widely spaced (50-200 km) mountain ranges and are typically extensive, intensely welded and rheomorphic. Paleomagnetic characterization of individual (paleosol-bounded) eruption-units together with field, petrographic and chemical characterization will aid in stratigraphic correlation between distant sections. By correlating and mapping the eruption-units we can better estimate how the frequencies and volumes of the super-eruptions changed during eastward progression of Yellowstone hotspot volcanism. This information helps distinguish between effects of thermal flux, crustal structure, and tectonics on magmatic history of this continental large igneous province. Additionally, large caldera collapse events dramatically modify landscapes, and location and scale of calderas may have significantly contributed to Snake River Plain topography. Over 300 paleomagnetic cores were collected in September 2010 from the Cassia Hills, Rogerson Graben, and Bruneau-Jarbidge regions in the southern margin of the Snake River Plain. We drilled 10 oriented cores per eruption unit at reference sections from each location and demagnetized them with alternating-field (AF) and thermal demagnetization techniques. In some cases AF treatment up to 200 mT was unable to completely destroy a specimen's natural remnant magnetization and so thermal treatment was used to finish the experiment. Zjiderveld diagrams from AF, thermal and hybrid experiments show

  2. Crustal structure and seismotectonics of central Sicily (southern Italy): new constraints from instrumental seismicity

    Science.gov (United States)

    Sgroi, Tiziana; de Nardis, Rita; Lavecchia, Giusy

    2012-06-01

    In this paper, we propose a new model of the crustal structure and seismotectonics for central Sicily (southern Italy) through the analysis of the depth distribution and kinematics of the instrumental seismicity, occurring during the period from 1983 to 2010, and its comparison with individual geological structures that may be active in the area. The analysed data set consists of 392 earthquakes with local magnitudes ranging from 1.0 to 4.7. We defined a new, detailed 1-D velocity model to relocate the earthquakes that occurred in central Sicily, and we calculated a Moho depth of 37 km and a mean VP/VS ratio of 1.73. The relocated seismic events are clustered mainly in the area north of Caltanissetta (e.g. Mainland Sicily) and in the northeastern sector (Madonie Mountains) of the study area; only minor and greatly dispersed seismicity is located in the western sector, near Belice, and along the southern coast, between Gela and Sciacca. The relocated hypocentral distribution depicts a bimodal pattern: 50 per cent of the events occur within the upper crust at depths less than ˜16 km, 40 per cent of the events occur within the middle and depth crust, at depths between 16 and 32 km, and the remaining 10 per cent occur at subcrustal depths. The energy release pattern shows a similar depth distribution. On the basis of the kinematic analysis of 38 newly computed focal plane solutions, two major geographically distinct seismotectonic domains are distinguished: the Madonie Mountain domain, with prevalent extensional and extensional-oblique kinematics associated with upper crust Late Pliocene-Quaternary faulting, and the Mainland Sicily domain, with prevalent compressional and compressional-oblique kinematics associated with thrust faulting, at mid to deep crust depth, along the north-dipping Sicilian Basal Thrust (SBT). The stress inversion of the Mainland Sicily focal solutions integrated with neighbouring mechanisms available in the literature highlights a regional

  3. Shifting shoals and shattered rocks : How man has transformed the floor of west-central San Francisco Bay

    Science.gov (United States)

    Chin, John L.; Wong, Florence L.; Carlson, Paul R.

    2004-01-01

    subembayments--north bay (San Pablo and Suisun Bays), central bay, and south bay--each characterized by a central area of open water surrounded by intertidal mudflats and marshes. Central bay includes Alcatraz and Angel Islands and also a number of submerged bedrock knobs that protrude through the sediment of the bay floor and rise to within about 40 feet (12 m) of the water surface. The most prominent of these are Harding, Shag, Arch, and Blossom Rocks. These rocks have been lowered by blasting several times in the past, but they remain a potential hazard to shipping because newer cargo vessels are designed with increasingly deeper drafts. Central bay's location adjacent to two major population and commerce centers, San Francisco and Oakland, subjects it to greater human influences than less developed parts of the estuary. The western part of central San Francisco Bay is adjacent to the Golden Gate, the estuary's outlet to the Pacific Ocean. The changing submarine topography of the west-central bay, as well as its geology, form the main focus of this book.

  4. Geochemistry and geochronology of meta-igneous rocks from the Tokat Massif, north-central Turkey: implications for Tethyan reconstructions

    Science.gov (United States)

    Catlos, Elizabeth J.; Huber, Kathryn; Shin, Timothy A.

    2013-11-01

    Located in the eastern Pontides of the Sakarya Zone in north-central Turkey, the Tokat Massif records the closure of both the Paleo-Tethyan (Karakaya Complex) and Neo-Tethyan ocean basins. Meta-igneous samples collected from the region were studied to determine their sources and ages. We find significant geochemical differences between metagabbros of the Karakaya and Neo-Tethyan units in terms of their trace elements: Neo-Tethyan rocks are consistent with generation in an island arc setting, whereas Karakaya assemblages were likely generated in an oceanic spreading-center environment. Karakaya metagabbros also contain glaucophane, consistent with subduction subsequent to formation. Small (2-50 μm) zircon and baddeleyite grains from four Karakaya metagabbros were dated in thin section using an ion microprobe. The results demonstrate the reliability of the method to directly constrain the tectonomagmatic history of these types of assemblages. The rocks yield Late Permian/Early Triassic 238U/206Pb crystallization ages of 258 ± 14 Ma (±1σ, zircon) and 254 ± 8 Ma (±1σ, baddeleyite) and an Early Cretaceous minimum metamorphic age of 137 ± 8 Ma (±1σ, zircon). Some zircon grains and baddeleyite grains with zircon overgrowths yield Early to Middle Jurassic ages. Here we present a model in which metamorphism and deformation in this region occurred during northward subduction and closure of a Paleo-Tethyan ocean basin and accretion of the Karakaya units to the Laurasian continental margin. This was followed by the onset of closure of the Neo-Tethys during the Campanian-Paleocene and accretion of island arc units to the Tokat region.

  5. U–Pb zircon and biostratigraphic data of high‐pressure/ low‐temperature metamorphic rocks of the Talea Ori : tracking the Paleotethys suture in central Crete, Greece

    NARCIS (Netherlands)

    Zulauf, G.; Dörr, W.; Krahl, J.; Lahaye, Y.; Chatzaras, V.|info:eu-repo/dai/nl/374329249; Xypolias, P.

    2016-01-01

    Inherited deformation microfabrics of detrital quartz grains and U–Pb (Laser ablation (LA)-ICPMS and ID TIMS) ages of detrital zircons separated from the Phyllite–Quartzite Unit s.l. of the Talea Ori, central Crete, suggest strikingly different source rocks. Albite gneiss of the lower Rogdia Beds

  6. Pliocene-Quaternary orogenic systems in Central Mediterranean: The Apulia-Southern Apennines-Tyrrhenian Sea example

    Science.gov (United States)

    Milia, Alfonsa; Torrente, Maurizio M.; Iannace, Pietro

    2017-08-01

    In the Central Mediterranean the Africa-Eurasia convergence led to the development of complex orogenic systems and back-arc basins. Throughout Pliocene-Quaternary times the Southern Apennines accretionary prism migrated toward the Apulia foreland and, contemporaneously, the Tyrrhenian Sea back-arc basin opened. In this study, we investigated the offshore of the southern Apulia foreland and the Southern Apennines. Using seismic reflection profiles and well data in a dedicated GIS software, we made a detailed stratigraphic analysis, reconstructed the structural pattern, and built 2-D geological models of the main geological surfaces. The structure of the Apulia region formed during two main tectonic stages: lower Pleistocene complex extensional faulting developed in a transtensional regime and middle-upper Pleistocene transpression/shortening. The Southern Apennines accretionary prism developed through the Pliocene-early lower Pleistocene and was overprinted by late lower Pleistocene-middle Pleistocene NW-SE sinistral faults. Through linking new data from the accretionary prism and the foreland with previous information from the Tyrrhenian Sea back-arc, we provide an original interpretation for the relationships between the various provinces that make the Central Mediterranean crustal puzzle and reconstruct the main phases of the evolution of its Pliocene-Quaternary orogenic cycle. We recognized collisional stages of uncoupled plates, followed by late lower-middle Pleistocene postcollisional stages of coupled continental plates. This Pleistocene plate reorganization of Central Mediterranean was probably due to the rupture of the Apulia/Ionian slab or to NNW intraplate shortening transmitted from Africa.

  7. Zircon geochronology of the Mashak volcanic rocks and the problem of the age of the lower-middle Riphean boundary (Southern Urals)

    Science.gov (United States)

    Krasnobaev, A. A.; Kozlov, V. I.; Puchkov, V. N.; Busharina, S. V.; Sergeeva, N. D.; Paderin, I. P.

    2013-09-01

    In the type sections of the Riphean within the Bashkirian mega-anticlinorium (Southern Urals), the Mashak Formation represents a basal unit of the Middle Riphean erathem. The formation comprises throughout its area of distribution the alternation of volcanic, volcano-sedimentary, and sedimentary sequences and is divided into the lower, middle, and upper subformations. The volcanic rocks containing zircons (four samples, rhyodacite and rhyolite collected at Mashak, Berezyak, and Bolshoi Shatak ranges) are largely confined to the lower subformation. Analyses were performed using a SHRIMP II methodology, with special attention to the mineralogical characteristics of zircons, including their habit, morphology, preservation, and inclusions. All zircons show similarities in their mineral chemistry and geochemistry, which are indicative of the geochemical affinity of the volcanic rocks. At the same time, all zircon grains are characterized by specific typological parameters, which may equally reflect the parameters involved in the development of such volcanic rocks under different conditions. The integrated U-Pb age of zircons (SHRIMP II, VSEGEI, St. Petersbrug) from the four samples is 1383 ± 3 Ma. On the basis of the age of the Berdyaush gabbro-granitoid intrusion (up to 1410 Ma), the most likely age of this boundary is 1400 Ma, which is equated to the Calymmian and Ectasian of the International Stratigraphic Scale.

  8. Irregular migration and informal economy in Southern and Central-Eastern Europe: breaking the vicious cycle?

    Science.gov (United States)

    Maroukis, Thanos; Iglicka, Krystyna; Gmaj, Katarzyna

    2011-01-01

    The flexible and cheap labour that European “post-industrial” economies are in need of is often facilitated by undeclared labour. The undocumented migrant, from his/her part, relatively easily finds work that suits his -- at least initial -- plans. What lies behind this nexus between irregular migration and informal economy? To what extent can this nexus be attributed to the structural features of the so-called “secondary”, as opposed to “primary”, labour market? And how does migration policy correlate with this economic context and lead to the entrapment of migrants in irregularity? Finally, can this vicious cycle of interests and life-strategies be broken and what does the experience of the migrants indicate in this respect? This paper addresses these questions via an exploration of the grounds upon which irregular migration and the shadow economy complement each other in southern Europe (SE) and central and Eastern Europe (CEE) (two regions at different points in the migration cycle). In doing so, the dynamic character of the nexus between informal economy and irregular migration will come to the fore, and the abstract identity of the “average” undocumented migrant will be deconstructed.

  9. 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. 

  10. Crust and Mantle Anisotropy Variations from the Coast to Inland In Central and Southern Mexico

    Science.gov (United States)

    Castillo, J. A.; Perez-Campos, X.; Husker, A. L.; Valenzuela Wong, R.

    2014-12-01

    We examine radial and tangential receiver functions (RFs) obtained along the Meso America Subduction Experiment (MASE), a profile from the Pacific coast in central-southern Mexico to the Gulf of Mexico. Tangential RFs show waveform variations in timing and polarity, both in the Moho and the slab Ps phases in function of its backazimuth; also, radial RFs show arrivals timing variation; all of which suggests a non-homogeneous horizontal layer medium. Using a particle motion analysis and a cross-correlation procedure, we are able to quantify the shear wave splitting in the continental crust, the subducted oceanic crust and the mantle below each station of the array in terms of a time delay, and a fast azimuth direction. From these variations, we distinguish between three major regions: 1) dipping subducted slab, 2) horizontal subducted slab, 3) absence of subducted slab. Results for region 1 are consistent with the geometry of the Cocos plate previously determined by other studies, showing a minimum energy content in the tangential RFs for the NE-SW geographic quadrants. In region 2, we identify a strong azimuthal dependence with a variable periodicity of 180° and 360° as well as the existence of "split" Ps phases in our data, possibly related to the presence of fluids and the ultra low velocity layer (ULVL) localized between the continental and oceanic crust. We compare these results with previous silent earthquakes (SSE) and non-volcanic tremors (NVT) studies in the area.

  11. Tectonic foliations and the distribution of landslides in the southern Central Range, Taiwan

    Science.gov (United States)

    Huang, Chung; Byrne, Timothy B.; Ouimet, William B.; Lin, Ching-Weei; Hu, Jyr-Ching; Fei, Li-Yuan; Wang, Yu-Bo

    2016-12-01

    Geometry of planner geological structures can interact with topographic slope and cause different types of slope failure (e.g. wedge failure, dip slope failure, and toppling etc.). This study focus on how the tectonic foliation influences the landslide pattern in the southern Central Range of Taiwan. The tectonic foliations in this area range from pencil cleavage to schistosity depending on the increasing of metamorphic grade, and different foliations have different influences on the landslide behaviors. To describe the relation between foliation and topographic slope, we create the θD value as the angle between the foliation dip direction azimuth and the topographic downslope direction azimuth at a given location. The location of landslides in the area with pencil cleavage has no preferential θD value, and it suggests the landslide distribution has no correlation with foliation. The location of landslides in the area with well-developed slaty cleavage is mostly in the lower θD value, which suggests the landslides are more likely located in the area where the foliation dip direction is parallel to the topographic downslope direction. The location of landslide in the area with schistosity is mostly in the high θD value area, which suggests the landslides are more likely located in the area where the foliation dip direction is opposite to the topographic downslope direction.

  12. Petrology and mineralogy of the La Peña igneous complex, Mendoza, Argentina: An alkaline occurrence in the Miocene magmatism of the Southern Central Andes

    Science.gov (United States)

    Pagano, Diego Sebastián; Galliski, Miguel Ángel; Márquez-Zavalía, María Florencia; Colombo, Fernando

    2016-04-01

    The La Peña alkaline igneous complex (LPC) is located in the Precordillera (32°41‧34″ S - 68°59‧48″ W) of Mendoza province, Argentina, above the southern boundary of the present-day flat-slab segment. It is a 19 km2 and 5 km diameter subcircular massif emplaced during the Miocene (19 Ma) in the Silurian-Devonian Villavicencio Fm. The LPC is composed of several plutonic and subvolcanic intrusions represented by: a cumulate of clinopyroxenite intruded by mafic dikes and pegmatitic gabbroic dikes, isolated bodies of malignite, a central intrusive syenite that develops a wide magmatic breccia in the contact with clinopyroxenite, syenitic and trachytic porphyries, a system of radial and ring dikes of different compositions (trachyte, syenite, phonolite, alkaline lamprophyre, tephrite), and late mafic breccias. The main minerals that form the LPC, ordered according to their abundance, are: pyroxene (diopside, hedenbergite), calcium amphibole (pargasite, ferro-pargasite, potassic-ferro-pargasite, potassic-hastingsite, magnesio-hastingsite, hastingsite, potassic-ferro-ferri-sadanagaite), trioctahedral micas (annite-phlogopite series), plagioclase (bytownite to oligoclase), K-feldspar (sanidine and orthoclase), nepheline, sodalite, apatite group minerals (fluorapatite, hydroxylapatite), andradite, titanite, magnetite, spinel, ilmenite, and several Cu-Fe sulfides. Late hydrothermal minerals are represented by zeolites (scolecite, thomsonite-Ca), epidote, calcite and chlorite. The trace element patterns, coupled with published data on Sr-Nd-Pb isotopes, suggest that the primary magma of the LPC was generated in an initially depleted but later enriched lithospheric mantle formed mainly by a metasomatized spinel lherzolite, and that this magmatism has a subduction-related signature. The trace elements pattern of these alkaline rocks is similar to other Miocene calc-alkaline occurrences from the magmatic arc of the Southern Central Andes. Mineral and whole-rock

  13. A new interpretation for the interference zone between the southern Brasília belt and the central Ribeira belt, SE Brazil

    Science.gov (United States)

    Trouw, Rudolph A. J.; Peternel, Rodrigo; Ribeiro, Andre; Heilbron, Mônica; Vinagre, Rodrigo; Duffles, Patrícia; Trouw, Camilo C.; Fontainha, Marcos; Kussama, Hugo H.

    2013-12-01

    In southeastern Brazil, the Neoproterozoic NNW-SSE trending southern Brasília belt is apparently truncated by the ENE-WSW central Ribeira belt. Different interpretations in the literature of the transition between these two belts motivated detailed mapping and additional age dating along the contact zone. The result is a new interpretation presented in this paper. The southern Brasília belt resulted from E-W collision between the active margin of the Paranapanema paleocontinent, on the western side, now forming the Socorro-Guaxupé Nappe, with the passive margin of the São Francisco paleocontinent on the eastern side. The collision produced an east vergent nappe stack, the Andrelândia Nappe System, along the suture. At its southern extreme the Brasília belt was thought to be cut off by a shear zone, the "Rio Jaguari mylonites", at the contact with the Embu terrane, pertaining to the Central Ribeira belt. Our detailed mapping revealed that the transition between the Socorro-Guaxupé Nappe (Brasília belt) and the Embu terrane (Ribeira belt) is not a fault but rather a gradational transition that does not strictly coincide with the Rio Jaguari mylonites. A typical Cordilleran type magmatic arc batholith of the Socorro-Guaxupé Nappe with an age of ca. 640 Ma intrudes biotite schists of the Embu terrane and the age of zircon grains from three samples of metasedimentary rocks, one to the south, one to the north and one along the mylonite zone, show a similar pattern of derivation from a Rhyacian source area with rims of 670-600 Ma interpreted as metamorphic overgrowth. We dated by LA-MC-ICPMS laser ablation (U-Pb) zircon grains from a calc-alkaline granite, the Serra do Quebra-Cangalha Batholith, located within the Embu terrane at a distance of about 40 km south of the contact with the Socorro Nappe, yielding an age of 680 ± 13 Ma. This age indicates that the Embu terrane was part of the upper plate (Socorro-Guaxupé Nappe) by this time. Detailed mapping

  14. Petrology and geochemistry of volcanic rocks from the island of Panarea: implications for mantle evolution beneath the Aeolian island arc (southern Tyrrhenian sea)

    Science.gov (United States)

    Calanchi, N.; Peccerillo, A.; Tranne, C. A.; Lucchini, F.; Rossi, P. L.; Kempton, P.; Barbieri, M.; Wu, T. W.

    2002-06-01

    Major, trace element and radiogenic isotope (Sr, Nd, Pb) data are reported for a suite of rocks from the Panarea volcano, a large structure that is largely hidden below sea level and outcrops only as a group of small islands between Lipari-Vulcano and Stromboli in the eastern Aeolian arc. The exposed rocks mostly consist of high-potassium calc-alkaline (HKCA) andesites, dacites and some rhyolites; shoshonitic basalts have been collected from submarine centres; mafic calc-alkaline (CA) rocks occur as thin layers of late-erupted strombolian scoriae. Major and trace element data are scattered, but define generally linear trends on inter-element diagrams; Sr-isotope ratios do not display significant increase with evolution, although rough positive trends of 87Sr/86Sr versus SiO2 and Rb/Sr can be recognised within some units. The mafic rocks display varying enrichment in potassium, from CA to shoshonitic compositions, and are characterised by variable abundances of incompatible trace elements, which increase with potassium. There is an increase of 87Sr/86Sr ratios and a decrease of 143Nd/144Nd and 206Pb/204Pb ratios from CA to HKCA and shoshonitic mafic rocks. The scattered and incomplete nature of the outcrops make it difficult to constrain magmatic evolution at Panarea; geochemical and isotopic data suggest that AFC and mixing were important evolutionary processes. However, geochemical modelling does not support the possibility that the first-order compositional variations observed in the mafic rocks are the result of these processes, and suggests a genesis in a heterogeneous mantle source. Recent studies have highlighted strong differences in terms of incompatible trace element ratios and isotopic signatures, between the western-central and the eastern Aeolian arc. Rocks from the western islands (Alicudi, Filicudi, Salina, Vulcano) have typical magmatic arc geochemical signatures and relatively unradiogenic Sr-isotope compositions. By contrast, the eastern island of

  15. Analysis of the central nervous system transcriptome of the eastern rock lobster Sagmariasus verreauxi reveals its putative neuropeptidome.

    Directory of Open Access Journals (Sweden)

    Tomer Ventura

    Full Text Available Neuropeptides have been discovered in many arthropod species including crustaceans. The nature of their biological function is well studied and varies from behavior modulation to physiological regulation of complex biochemical processes such as metabolism, molt and reproduction. Due to their key role in these fundamental processes, neuropeptides are often targeted for modulating these processes to align with market demands in commercially important species. We generated a comprehensive transcriptome of the eyestalk and brain of one of the few commercially important spiny lobster species in the southern Hemisphere, the Eastern rock lobster Sagmariasus verreauxi and mined it for novel neuropeptide and protein hormone-encoding transcripts. We then characterized the predicted mature hormones to verify their validity based on conserved motifs and features known from previously reported hormones. Overall, 37 transcripts which are predicted to encode mature full-length/partial peptides/proteins were identified, representing 21 peptide/protein families/subfamilies. All transcripts had high similarity to hormones that were previously characterized in other decapod crustacean species or, where absent in crustaceans, in other arthropod species. These included, in addition to other proteins previously described in crustaceans, prohormone-3 and prohormone-4 which were previously identified only in insects. A homolog of the crustacean female sex hormone (CFSH, recently found to be female-specific in brachyuran crabs was found to have the same levels of expression in both male and female eyestalks, suggesting that the CFSH female specificity is not conserved throughout decapod crustaceans. Digital gene expression showed that 24 out of the 37 transcripts presented in this study have significant changes in expression between eyestalk and brain. In some cases a trend of difference between males and females could be seen. Taken together, this study provides a

  16. Relationship between the Layered Series and the overlying evolved rocks in the Bjerkreim-Sokndal Intrusion, southern Norway

    DEFF Research Database (Denmark)

    Wilson, James Richard; Overgaard, Gitte

    2005-01-01

    The Bjerkreim-Sokndal layered intrusion (BKSK) consists of a >7000 m-thick Layered Series comprising anorthosites, leuconorites, troctolites, norites, gabbronorites and jotunites (hypersthene monzodiorites), overlain by an unknown thickness of massive, evolved rocks: mangerites (hypersthene...... are essentially constant in the upper part of the MG-unit and in the QMG (An21-13; Fo6-4; Mg#opx17-13; Mg#cpx25-20). The amount of interstitial quartz and the amount of normative orthoclase, however, both increase systematically upwards through the QMG-unit, implying that these rocks are cumulates...

  17. The Morsárjökull rock avalanche in the southern part of the Vatnajökull glacier, south Iceland

    Science.gov (United States)

    Sæmundsson, Şorsteinn; Sigurősson, Ingvar A.; Pétursson, Halldór G.; Decaulne, Armelle; Jónsson, Helgi P.

    2010-05-01

    On the 20th of March 2007 a large rock avalanche fell on Morsárjökull, one of the outlet glaciers from the southern part of the Vatnajökull ice cap, in south Iceland. This is considered to be one of the largest rock avalanches which have occurred in Iceland during the last decades. It is believed that it fell in two separate stages, the main part fell on the 20th of March and the second and smaller one, on the 17th of April 2007. The Morsárjökull outlet glacier is about 4 km long and surrounded by up to 1000 m high valley slopes. The outlet glacier is fed by two ice falls which are partly disconnected to the main ice cap of Vatnajökull, which indicates that the glacier is mainly fed by ice avalanches. The rock avalanche fell on the eastern side of the uppermost part of the Morsárjökull outlet glacier and covered about 1/5 of the glacier surface, an area of about 720,000 m2. The scar of the rock avalanche is located on the north face of the headwall above the uppermost part of the glacier. It is around 330 m high, reaching from about 620 m up to 950 m, showing that the main part of the slope collapsed. It is estimated that about 4 million m3 of rock debris fell on the glacier, or about 10 million tons. The accumulation lobe is up to 1.6 km long, reaching from 520 m a.s.l., to about 350 m a.s.l. Its width is from 125 m to 650 m, or on average 480 m. The total area which the lobe covers is around 720.000 m2 and its mean thickness 5.5 m. The surface of the lobe shows longitudinal ridges and grooves and narrow flow-like lobes, indicating that the debris mass evolved down glacier as a mixture of a slide and debris flow. The debris mass is coarse grained and boulder rich. Blocks over 5 to 8 m in diameter are common on the edges of the lobe up to 1.6 km from the source. No indication was observed of any deformation of the glacier surface under the debris mass. The first glaciological measurements of Morsárjökull outlet glacier were carried out in the year 1896

  18. Black shale source rocks and oil generation in the Cambrian and Ordovician of the central Appalachian Basin, USA

    Science.gov (United States)

    Ryder, R.T.; Burruss, R.C.; Hatch, J.R.

    1998-01-01

    Nearly 600 million bbl of oil (MMBO) and 1 to 1.5 trillion ft3 (tcf) of gas have been produced from Cambrian and Ordovician reservoirs (carbonate and sandstone) in the Ohio part of the Appalachian basin and on adjoining arches in Ohio, Indiana, and Ontario, Canada. Most of the oil and gas is concentrated in the giant Lima-Indiana field on the Findlay and Kankakee arches and in small fields distributed along the Knox unconformity. Based on new geochemical analyses of oils, potential source rocks, bitumen extracts, and previously published geochemical data, we conclude that the oils in both groups of fields originated from Middle and Upper Ordovician blcak shale (Utica and Antes shales) in the Appalachian basin. Moroever, we suggest that approximately 300 MMBO and many trillions of cubic feet of gas in the Lower Silurian Clinton sands of eastern Ohio originated in the same source rocks. Oils from the Cambrian and Ordovician reservoirs have similar saturated hydrocarbon compositions, biomarker distributions, and carbon isotope signatures. Regional variations in the oils are attributed to differences in thermal maturation rather than to differences in source. Total organic carbon content, genetic potential, regional extent, and bitument extract geochemistry identify the balck shale of the Utica and Antes shales as the most plausible source of the oils. Other Cambrian and Ordovician shale and carbonate units, such as the Wells Creek formation, which rests on the Knox unconformity, and the Rome Formation and Conasauga Group in the Rome trough, are considered to be only local petroleum sources. Tmax, CAI, and pyrolysis yields from drill-hole cuttings and core indicate that the Utica Shale in eastern and central Ohio is mature with respect to oil generation. Burial, thermal, and hydrocarbon-generation history models suggest that much of the oil was generated from the Utica-Antes source in the late Paleozoic during the Alleghanian orogeny. A pervasive fracture network

  19. Estimation of the radon production rate in granite rocks and evaluation of the implications for geogenic radon potential maps: A case study in Central Portugal.

    Science.gov (United States)

    Pereira, A; Lamas, R; Miranda, M; Domingos, F; Neves, L; Ferreira, N; Costa, L

    2017-01-01

    The goal of this study was to estimate radon gas production rate in granitic rocks and identify the factors responsible for the observed variability. For this purpose, 180 samples were collected from pre-Hercynian and Hercynian rocks in north and central Portugal and analysed for a) (226)Ra activity, b) radon ((222)Rn) per unit mass activity, and c) radon gas emanation coefficient. On a subset of representative samples from the same rock types were also measured d) apparent porosity and e) apparent density. For each of these variables, the values ranged as follows: a) 15 to 587 Bq kg(-1), b) 2 to 73 Bq kg(-1), c) 0.01 to 0.80, d) 0.3 to 11.4 % and e) 2530 to 2850 kg m(-3). Radon production rate varied between 40 to 1386 Bq m(-3) h(-1). The variability observed was associated with geologically late processes of low and high temperature which led to the alteration of the granitic rock with mobilization of U and increase in radon (222)Rn gas emanation. It is suggested that, when developing geogenic radon potential maps, data on uranium concentration in soils/altered rock should be used, rather than data obtained from unaltered rock. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. The carbon balance in natural and disturbed forests of the southern taiga in central Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Vedrova, E.F.; Shugalei, L.S.; Stakanov, V.D. [Russian Academy of Sciences, Kasnoyarsk (Russian Federation) V.N. Sukachev Inst. of Forest and Wood

    2002-06-01

    We evaluated the balance of production and decomposition in natural ecosystems of Pinus sylvestris, Larix sibirica and Betula pendula in the southern boreal forests of central Siberia, using the Yenisei transect. We also investigated whether anthropogenic disturbances (logging, fire and recreation pressure) influence the carbon budget. Pinus and Larix stands up to age class VI act as a net sink for atmospheric carbon. Mineralization rates in young Betula forests exceed rates of uptake via photosynthesis assimilation. Old-growth stands of all three forest types are CO{sub 2} sources to the atmosphere. The prevalence of old-growth Larix in the southern taiga suggests that Larix stands are a net source of CO{sub 2}. The CO{sub 2} flux to the atmosphere exceeds the uptake of atmospheric carbon via photosynthesis by 0.23 t C/ha/yr (47%). Betula and Pinus forests are net sinks, as photosynthesis exceeds respiration by 13% and 16% respectively. The total carbon flux from Pinus, Larix and Betula ecosystems to the atmosphere is 10,387 thousand tons C/yr. Net Primary Production (0.935 t-C/ha) exceeds carbon release from decomposition of labile and mobile soil organic matter (Rh) by 767 thousand tons C (0.064 t-C/ha), so that these forests are net C-sinks. The emissions due to decomposition of slash (101 thousand tons C; 1.0%) and from fires (0.21%) are very small. The carbon balance of human-disturbed forests is significantly different. A sharp decrease in biomass stored in Pinus and Betula ecosystems leads to decreased production. As a result, the labile organic matter pool decreased by 6-8 times; course plant residues with a low decomposition rate thus dominate this pool. Annual carbon emissions to the atmosphere from these ecosystems are determined primarily by decomposing fresh litterfall. This source comprises 40-79% of the emissions from disturbed forests compared to only 13-28% in undisturbed forests. The ratio of emissions to production (NPP) is 20-30% in disturbed

  1. Viability criteria for steelhead of the south-central and southern California coast

    Science.gov (United States)

    Boughton, David A.; Adams, Peter B.; Anderson, Eric; Fusaro, Craig; Keller, Edward A.; Kelley, Elsie; Lentsch, Leo; Nielsen, Jennifer L.; Perry, Katie; Regan, Helen; Smith, Jerry; Swift, Camm C.; Thompson, Lisa; Watson, Fred

    2007-01-01

    Recovery planning for threatened and endangered steelhead requires measurable, objective criteria for determining an acceptably low risk of extinction. Here we propose viability criteria for two levels of biological organization: individual populations, and groups of populations within the SouthCentral/Southern California Coast Steelhead Recovery Planning Domain. For populations, we adapt criteria commonly used by the IUCN (The World Conservation Union) for identifying at-risk species. For groups of populations we implement a diversity-based “representation and redundancy rule,” in which diversity includes both life-history diversity and biogeographic groupings of populations. The resulting criteria have the potential for straightforward assessment of the risks posed by evolutionary, demographic, environmental, and catastrophic factors; and are designed to use data that are readily collected. However, our prescriptive approach led to one criterion whose threshold could not yet be specified due to inadequate data, and others in which the simplicity of the criteria may render them inefficient for populations with stable run sizes or stable life-history polymorphisms. Both of these problems could likely be solved by directed programs of research and monitoring aimed at developing more efficient (but equally risk-averse) “performance-based criteria.” Of particular utility would be data on the natural fluctuations of populations, research into the stabilizing influence of life-history polymorphisms, and research on the implications of drought, wildfires, and fluvial sediment regimes. Research on estuarine habitat could also yield useful information on the generality and reliability of its role as nursery habitat. Currently, risk assessment at the population level is not possible due to data deficiency, highlighting the need to implement a comprehensive effort to monitor run sizes, anadromous fractions, spawner densities and perhaps marine survival. Assessment at

  2. Ages and origin of felsic rocks from the Eastern Erenhot ophiolitic complex, southeastern Central Asian Orogenic Belt, Inner Mongolia China

    Science.gov (United States)

    Yang, Jinfu; Zhang, Zhicheng; Chen, Yan; Yu, Haifei; Qian, Xiaoyan

    2017-08-01

    The Central Asian Orogenic Belt (CAOB) is known for its massive Phanerozoic generation of juvenile crust. The tectonic evolution of the CAOB during the late Paleozoic era is still debated. The Eastern Erenhot ophiolite complex (EOC) has been recognized as one of the numerous late Paleozoic ophiolitic blocks in the southeastern part of the CAOB. Zircon U-Pb dating on rhyolite and plagiogranite from the EOC yielded a tight range of ages from 360 to 348 Ma, indicating that the complex formed in the early Carboniferous. The primitive mantle-normalized spider diagram of rhyolites (εNd(t) values of +6.8 and +7) and basalts almost overlaps. Such rhyolites may have been derived from partial melting of juvenile basaltic rocks during the initial opening of the Erenhot-Hegenshan oceanic basin. All of the plagiogranites exhibit similar trace element behaviours of High Field-Strength Elements, such as U, Zr and Hf, and Large Ion Lithophile Elements, such as Ba and Rb, to these of gabbros. These plagiogranites were considered products of episodes of partial melting of hydrous gabbros during ocean floor spreading. We conclude that the northern subduction of the Paleo-Asian Ocean stopped before 360 Ma and the southeastern CAOB experienced extension during the late Paleozoic era. The Erenhot-Hegenshan Ocean, which is comparable to the present Red Sea, originated from syn-collisional crustal thickening, subsequent lithosphere extension, and upwelling of the asthenosphere during orogenic quiescence with an age of 20 Ma.

  3. Intergarted geophysical investigations by GPR and ERT on the largest rock fill dam in Europe: Monte Cotugno dam (Southern Italy)

    Science.gov (United States)

    Loperte, A.; Bavusi, M.; Cerverizzo, G.; Lapenna, V.; Soldovieri, F.

    2012-04-01

    This work is concerned with the first results of a survey based on the integration of geophysical techniques for the inspection of the Monte Cotugno dam, the largest rock fill dam in Europe. The Monte Cotugno dam, managed by National Irrigation Development and Agrarian Transformation in Puglia, Basilicata and Irpinia is located on the Sinni river (Basilicata District, South Italy) and represents the nodal point in the whole hydraulic system on the Ionic side of Italy; in fact, the dam allows harnessing of the Sinni river water for agricultural, industrial, drinking and domestic purposes. The dam is of the zoned type and consists of a central core in sandy silt and of gravelly-sandy shoulders; its water tightness is ensured by a bituminous conglomerate facing on the upstream side, welded at the bottom to the foundation sealing system. The latter is about 1,900m long and consist of a massive concrete cut-off wall based on the marly-clay formation, 300m long on the right and 600 m long on the left side. On the valley bottom it is made up of a reinforced concrete cut-off wall that is inserted in the marly-clay formation and is surmounted by an inspection and percolation water collection tunnel. The watertight face consists of a bottom levelling layer 7-8 cm thick in semi open-graded bituminous concrete, a 5 cm separation layer in dense-graded bituminous concrete, a drainage layer in very open-graded concrete varying in thickness from 10 to 16 cm from the top of the dam down, two 4-cm top layers in dense-graded bituminous concrete with stepped joints, a finishing sealing coat containing 1.5 kg/cm2 of asphalt. The shallowest part of this layering is started to show incipient small detachments due to thermal solicitations; these detachments represent a possible way for water infiltration in the dam. In this framework, it was decided to perform the identification, characterization and evaluation of the potential loss of water through small cracks in the bituminous concrete

  4. Igneous activity and related ore deposits in the western and southern Tushar Mountains, Marysvale volcanic field, west-central Utah

    Science.gov (United States)

    Steven, Thomas A.

    1984-01-01

    16 m.y. old may exist near Indian Creek just west of the Mount Belknap caldera. Geophysical evidence confirms the probability of a buried pluton near Indian Creek, and also indicates that another buried pluton probably exists beneath the 9-m.y.-old mineralized area at Sheep Rock. The mineral potential of the different hydrothermal systems, and the types of minerals deposited probably vary considerably from one period of mineralization to another and from one depth environment to another within a given system. PART B: The Big John caldera, on the western flank of the Tushar Mountains in the Marysvale volcanic field in west-central Utah, formed 23-22 m.y. ago in response to ash-flow eruptions of the Delano Peak Tuff Member of the Bullion Canyon Volcanics. These eruptions were near the end of the period of Oligocene-early Miocene calc-alkalic igneous activity that built a broad volcanic plateau in this part of Utah. About 22 m.y. ago, the composition of rocks erupted changed to a bimodal assemblage of mafic and silicic volcanics that was erupted episodically through the remainder of Cenozoic time. The alkali rhyolites are uranium rich in part, and are associated with all the known uranium deposits in the Marysvale volcanic field. The Big John caldera was a broad drained basin whose floor was covered by a layer of stream gravels when ash flows from the western source area of the Mount Belknap Volcanics filled the caldera with the Joe Lott Tuff Member about 19 m.y. ago. Devitrified and zeolitized rocks in the caldera fill have lost one-quarter to one-half of the uranium contained in the original magma. This mobilized uranium probably moved into the hydrologic regime, and some may have been redeposited in stream gravels underlying the Joe Lott within the caldera, or in gravels filling the original drainage channel that extended south from the caldera.

  5. Two new species of Andean gymnophthalmid lizards of the genus Euspondylus (Reptilia, Squamata) from central and southern Peru

    Science.gov (United States)

    Chávez, Germán; Siu-Ting, Karen; Duran, Vilma; Venegas, Pablo J

    2011-01-01

    Abstract Two new species of lizards assigned to the genus Euspondylus from the montane forests of the Peruvian Andes in the Pasco Department (central Peru) and Ayacucho Department (southern Peru) both at elevations of 2550 and 3450 m, respectively, are described. The new species are distinguishable from all other Peruvian and Ecuadorian species of Euspondylus by a unique combination of morphometric, scalation and color pattern characteristics. Natural history data for the new species and for Euspondylus spinalis are also provided. PMID:21852931

  6. Prevalence of Strongyloides stercoralis and other intestinal parasitic infections among mentally retarded residents in central institution of southern Iran

    OpenAIRE

    Azar Shokri; Khojasteh Sharifi Sarasiabi; Saeed Hosseini Teshnizi; Hamid Mahmoodi

    2012-01-01

    Objective: To determine the prevalence of intestinal parasitic infections among mentally retarded residents of rehabilitation center of Bandar Abbas, Hormozgan province, southern Iran. Methods: A cross-sectional study was carried out in central rehabilitation institute of Hormozgan province in summer 2010. Fecal samples of all 133 residents (72 males, 61 females) aged 3-52, were collected in triplicate. Specimens were examined by direct smear, formalin-ether concentration techniques and st...

  7. Subduction zone processes and continental crust formation in the southern Central Andes: insights from geochemistry and geochronology

    OpenAIRE

    Jones, Rosemary Ellen

    2014-01-01

    Subduction zones, such as the Andean convergent margin, are the sites at which new continental crust is generated, and where subducting material is either recycled to the crust via arc magmatism or transferred to the deep mantle. The composition of arc magmas and associated new continental crust reflects variable contributions from mantle, crustal and subducted reservoirs. Insights into crustal growth and recycling processes in the southern Central Andes, specifically in the ...

  8. Quaternary, catastrophic rock avalanches in the Central Apennines (Italy): Relationships with inherited tectonic features, gravity-driven deformations and the geodynamic frame

    Science.gov (United States)

    Bianchi Fasani, G.; Di Luzio, E.; Esposito, C.; Evans, S. G.; Scarascia Mugnozza, G.

    2014-04-01

    Five cases of Quaternary rock avalanches detached from carbonate mountain ridges in the Central Apennines are presented. Due to the large amount of rock masses involved, the width of accumulation and detachment areas and the damming in the host environment, the analysed rock avalanches can be considered as catastrophic rock slope failures, sporadic events in a mountain region characterized by low elevation but where mountain ridges can have a relative elevation of up to 1 km above the lowermost valley floors. The geological setting of tectonic structures that originated during the Apennine orogenesis influenced rock avalanche characteristics, determining the location and shape of detachment areas, the kind of rock mass involved, and the failure mechanisms. Two main types have been identified: i) forelimb rock-slide avalanches (FRSA) such as the Lettopalena and Mt. Arezzo rock avalanche which involved Cenozoic, heterogeneous sequences of carbonate ramp deposits detached from box-shaped source areas according to a rock sliding mechanism; and ii) backlimb slide-wedge rock avalanches (BSWRA) such as the Campo di Giove, Scanno and Celano rock avalanches that detached from sub-circular source areas carved on fault-bounded ridges and involving Meso-Cenozoic carbonate rocks with a combined sliding and rock wedge failure mechanism. The Campo di Giove, Lettopalena and Scanno rock avalanches originated from mountain ridges bounded by inactive fault zones and undergoing deep-seated gravitational slope deformations (DSGSDs) at the mountain scale. These three rock slope failures are considered as isolated events of long-lasting deformative processes featuring creep deformation. Gravity-driven deformations firstly generated as a response to stacking processes and synchronous normal faulting during the Neogene-Early Pleistocene Apennine tectonics. In particular, the Caramanico Fault System (CFS) and the Genzana Fault (GF), bordering the carbonate ridges from which the Campo di

  9. Geomorphological and structural characterization of the southern Weihe Graben, central China: Implications for fault segmentation

    Science.gov (United States)

    Cheng, Yali; He, Chuanqi; Rao, Gang; Yan, Bing; Lin, Aiming; Hu, Jianmin; Yu, Yangli; Yao, Qi

    2018-01-01

    The Cenozoic graben systems around the tectonically stable Ordos Block, central China, have been considered as ideal places for investigating active deformation within continental rifts, such as the Weihe Graben at the southern margin with high historical seismicity (e.g., 1556 M 8.5 Huaxian great earthquake). However, previous investigations have mostly focused on the active structures in the eastern and northern parts of this graben. By contrast, in the southwest, tectonic activity along the northern margin of the Qinling Mountains has not been systematically investigated yet. In this study, based on digital elevation models (DEMs), we carried out geomorphological analysis to evaluate the relative tectonic activity along the whole South Border Fault (SBF). On the basis of field observations, high resolution DEMs acquired by small unmanned aerial vehicles (sUVA) using structure-for-motion techniques, radiocarbon (14C) age dating, we demonstrate that: 1) Tectonic activity along the SBF changes along strike, being higher in the eastern sector. 2) Seven major segment boundaries have been assigned, where the fault changes its strike and has lower tectonic activity. 3) The fault segment between the cities of Huaxian and Huayin characterized by almost pure normal slip has been active during the Holocene. We suggest that these findings would provide a basis for further investigating on the seismic risk in densely-populated Weihe Graben. Table S2. The values and classification of geomorphic indices obtained in this study. Fig. S1. Morphological features of the stream long profiles (Nos. 1-75) and corresponding SLK values. Fig. S2. Comparison of geomorphological parameters acquired from different DEMs (90-m SRTM and 30-m ASTER GDEM): (a) HI values; (b) HI linear regression; (c) mean slope of drainage basin; (d) mean slope linear regression.

  10. Stratigraphy of the Younger Dryas Chronozone and paleoenvironmental implications: Central and Southern Great Plains

    Science.gov (United States)

    Holliday, V.T.; Meltzer, D.J.; Mandel, R.

    2011-01-01

    The Great Plains of the United States was the setting for some of the earliest research in North America into patterns and changes in the character of late Pleistocene environments and their effects on contemporary human populations. Many localities in the region have well-stratified records of terminal Pleistocene and early Holocene human (Paleoindian) activity and past environments. These have proven important in debates over the character of the Younger Dryas Chronozone (YDC; 11,000-10,000 14C BP; 12,900-11,700 cal BP) in the continental interior. This paper reviews the lithostratigraphic record of the YDC on the Central and Southern Great Plains and summarizes paleobiological records (largely isotopic). The goal is to determine if there is any uniformity in the timing, character, direction and/or magnitude of changes in depositional environments or broader geomorphic systems before, during or after the YDC in order to address the question of the character of environments through this time. The stratigraphic records of the late Pleistocene to early Holocene transition, and in particular, the stratigraphic records of the YDC vary through time and space. The data clearly show that a host of geomorphic processes produced the terminal Pleistocene and early Holocene stratigraphic records of the Great Plains. Moreover, the YDC is not necessarily manifest as a distinct lithostratigraphic or biostratigraphic entity in these different types of deposits and soils. The various geomorphic systems of the Great Plains did not behave synchronously in response to any common climate driver. These stratigraphic records reflect local environmental conditions and probably a complex response to the reorganization of mid-latitude climates in the terminal Pleistocene and early Holocene. ?? 2011 Elsevier Ltd and INQUA.

  11. Genetic structure analysis of Spirometra erinaceieuropaei isolates from central and southern China.

    Directory of Open Access Journals (Sweden)

    Xi Zhang

    Full Text Available Sparganosis caused by invasion of the plerocercoid larvae (spargana of Spirometra erinaceieuropaei have increased in recent years in China. However, the population genetic structure regarding this parasite is still unclear. In this study, we used the sequences of two mitochondrial genes cytochrome b (cytb and cytochrome c oxidase subunit I (cox1 to analyze genetic variation and phylogeographic structure of the S. erinaceieuropaei populations.A total of 88 S. erinaceieuropaei isolates were collected from naturally infected frogs in 14 geographical locations of China. The complete cytb and cox1 genes of each sample was amplified and sequenced. Total 61 haplotypes were found in these 88 concatenated sequences. Each sampled population and the total population have high haplotype diversity (Hd, accompanied by very low nucleotide diversity (Pi. Phylogenetic analyses of haplotypes revealed two distinct clades (HeN+HuN+GZ-AS clade and GX+HN+GZ-GY clade corresponding two sub-networks yielded by the median-joining network. Pairwise FST values supported great genetic differentiation between S. erinaceieuropaei populations. Both negative Fu's FS value of neutrality tests and unimodal curve of mismatch distribution analyses supported demographic population expansion in the HeN+HuN+GZ-AS clade. The BEAST analysis showed that the divergence time between the two clades took place in the early Pleistocene (1.16 Myr, and by Bayesian skyline plot (BSP an expansion occurred after about 0.3 Myr ago.S. erinaceieuropaei from central and southern China has significant phylogeographic structure, and climatic oscillations during glacial periods in the Quaternary may affect the demography and diversification of this species.

  12. The epidemiological aspects of congenital heart disease in central and southern district of Iran

    Directory of Open Access Journals (Sweden)

    Sara Amel-Shahbaz

    2014-01-01

    Full Text Available Background: Congenital heart disease (CHD is a major health problem and its prevalence is different around the world. The aim of study was determination of the epidemiological aspects of CHD in central and southern district of Iran. Materials and Methods: In this descriptive and analytical study, 3714 medical records were evaluated from March 21, 2001 to December 18, 2011. Medical records of inpatients from angiography and outpatients in the Heart Clinic of Afshar hospital (a referral hospital in center and south of Iran were the source of information. Types of CHD and demographic data including age, sex and residential location are collected. The data were analyzed by SPSS (version 17 software. Chi-square and Fisher′s exact tests were used to compare variables between groups. Results: At the study, the mean age of the patients at diagnosis time was 8.8 ± 11.6 year (at the range of one day to 76 years with median of 4 years. The percentage of females and males was 54.2 (n: 2014 and 43.8 (n: 1627, respectively. The chi-square test showed that there was significant difference in frequency of CHDs between females and males (P value < 0.0001. Ventricular septal defect (VSD was found to be the most frequent of CHDs (27%. Patent ductus arteriosus (PDA (16.8%, atrial septal defect (ASD (15.8%, pulmonary stenosis (PS (11% and Tetralogy of Fallot (TOF (8.9% were more prevalent in CHDs after VSD. Conclusions: The frequency of CHDs in female was more than male and VSD, PDA, ASD, PS, and TOF were most common in CHDs, respectively.

  13. Atmospheric circulation associated with extreme generalized frosts persistence in central-southern South America

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Gabriela V. [Centro de Investigaciones Cientificas y Transferencia de Tecnologia a la Produccion, Diamante (CICYTTTP-CONICET), Diamante, Entre Rios (Argentina); Berri, Guillermo J. [Servicio Meteorologico Nacional - CONICET, Buenos Aires (Argentina)

    2012-03-15

    Generalized frosts (GF) in central-southern South America have a strong impact due to their spatial extension, and they are especially important when they become persistent. This paper aims at identifying the atmospheric circulation features that determine the extreme GF persistence, i.e. very persistent and without persistence, and the differences between them, during the 1961-1990 winters. Since the GF without persistence group outnumbers the other one, two subgroups are composed with events selected from winters with maximum and minimum frequency of GF occurrence, respectively. Additionally, the individual event of July 1988 within the very persistent GF group is analyzed due to its exceptional persistence. GF persistence is mainly conditioned by two large-scale dynamic factors. One is the Rossby wave train propagation across the Pacific Ocean, and the other one is the location with respect to the continent and the magnitude of the confluence in the jet entrance region in subtropical latitudes. A predominantly meridional Rossby wave train propagation with a confluence region to the west of the continent prior to the event favors GF with intermediate (null) persistence depending on the greater (lesser) jet acceleration. This is conditioned by the magnitude of the confluence, which, in turn, depends on the disposition of the wave train propagation pattern. Instead, an essentially zonal propagation with a confluence region to the east of the continent favors the GF persistence for several days, yet if there is no confluence the event does not persist. The greatest persistence of an event combines the confluence/diffluence of the jet entrance/exit region, which depends on the disposition with respect to the continent of the zonally propagating Rossby wave trains. (orig.)

  14. Genetic structure analysis of Spirometra erinaceieuropaei isolates from central and southern China.

    Science.gov (United States)

    Zhang, Xi; Cui, Jing; Liu, Li Na; Jiang, Peng; Wang, Han; Qi, Xin; Wu, Xing Qi; Wang, Zhong Quan

    2015-01-01

    Sparganosis caused by invasion of the plerocercoid larvae (spargana) of Spirometra erinaceieuropaei have increased in recent years in China. However, the population genetic structure regarding this parasite is still unclear. In this study, we used the sequences of two mitochondrial genes cytochrome b (cytb) and cytochrome c oxidase subunit I (cox1) to analyze genetic variation and phylogeographic structure of the S. erinaceieuropaei populations. A total of 88 S. erinaceieuropaei isolates were collected from naturally infected frogs in 14 geographical locations of China. The complete cytb and cox1 genes of each sample was amplified and sequenced. Total 61 haplotypes were found in these 88 concatenated sequences. Each sampled population and the total population have high haplotype diversity (Hd), accompanied by very low nucleotide diversity (Pi). Phylogenetic analyses of haplotypes revealed two distinct clades (HeN+HuN+GZ-AS clade and GX+HN+GZ-GY clade) corresponding two sub-networks yielded by the median-joining network. Pairwise FST values supported great genetic differentiation between S. erinaceieuropaei populations. Both negative Fu's FS value of neutrality tests and unimodal curve of mismatch distribution analyses supported demographic population expansion in the HeN+HuN+GZ-AS clade. The BEAST analysis showed that the divergence time between the two clades took place in the early Pleistocene (1.16 Myr), and by Bayesian skyline plot (BSP) an expansion occurred after about 0.3 Myr ago. S. erinaceieuropaei from central and southern China has significant phylogeographic structure, and climatic oscillations during glacial periods in the Quaternary may affect the demography and diversification of this species.

  15. Retroarc basin reorganization and aridification during Paleogene uplift of the southern central Andes

    Science.gov (United States)

    Fosdick, J. C.; Reat, E. J.; Carrapa, B.; Ortiz, G.; Alvarado, P. M.

    2017-03-01

    Tectonic development of the Andean Cordillera has profoundly changed the topography, climate, and vegetation patterns of the southern central Andes. The Cenozoic Bermejo Basin in Argentina ( 30°S) provides a key record of thrust belt kinematics and paleoclimate south of the high-elevation Puna Plateau. Ongoing debate regarding the timing of initiation of upper plate shortening and Andean uplift persists, precluding a thorough understanding of the earlier tectonic and climatic controls on basin evolution. We present new sedimentology, detrital geochronology, sandstone petrography, and subsidence analysis from the Bermejo Basin that reveal siliciclastic-evaporative fluvial and lacustrine environments prior to the main documented phase of Oligocene-Miocene shortening of the Frontal Cordillera and Argentine Precordillera. We report the first radiometric dates from detrital zircons collected in the Ciénaga del Río Huaco Formation, previously mapped as Permian, that constrain a Late Cretaceous ( 95-93 Ma) maximum depositional age. Provenance and paleocurrent data from these strata indicate that detritus was derived from dissected arc and cratonic sources in the north and northeast. Detrital zircon U-Pb ages of 37 Ma from the overlying red beds suggest that foredeep sedimentation began by at least the late Eocene. At this time, sediment dispersal shifted from axial southward to transversal eastward from the Andean Arc and Frontal Cordillera. Subsidence analysis of the basin fill is compatible with increasing tectonic deformation beginning in Eocene time, suggesting that a distal foredeep maintained fluvial connectivity to the hinterland during topographic uplift and unroofing of the Frontal Cordillera, prior to Oligocene-Miocene deformation across the Precordillera.

  16. Decrease in water clarity of the southern and central North Sea during the 20th century.

    Science.gov (United States)

    Capuzzo, Elisa; Stephens, David; Silva, Tiago; Barry, Jon; Forster, Rodney M

    2015-06-01

    Light in the marine environment is a key environmental variable coupling physics to marine biogeochemistry and ecology. Weak light penetration reduces light available for photosynthesis, changing energy fluxes through the marine food web. Based on published and unpublished data, this study shows that the central and southern North Sea has become significantly less clear over the second half of the 20th century. In particular, in the different regions and seasons investigated, the average Secchi depth pre-1950 decreased between 25% and 75% compared to the average Secchi depth post-1950. Consequently, in summer pre-1950, most (74%) of the sea floor in the permanently mixed area off East Anglia was within the photic zone. For the last 25+ years, changes in water clarity were more likely driven by an increase in the concentration of suspended sediments, rather than phytoplankton. We suggest that a combination of causes have contributed to this increase in suspended sediments such as changes in sea-bed communities and in weather patterns, decreased sink of sediments in estuaries, and increased coastal erosion. A predicted future increase in storminess (Beniston et al., 2007; Kovats et al., 2014) could enhance the concentration of suspended sediments in the water column and consequently lead to a further decrease in clarity, with potential impacts on phytoplankton production, CO2 fluxes, and fishery production. © 2015 Crown copyright. Global Change Biology published by John Wiley & Sons Ltd. This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

  17. Technological homogeneity within the Arabian Nubian Complex: Comparing chert and quartzite assemblages from central and southern Arabia

    Directory of Open Access Journals (Sweden)

    Yamandú H. Hilbert

    2016-09-01

    Full Text Available Nubian Levallois technology is the defining characteristic of the Middle Paleolithic or Middle Stone Age technocomplex known as the Nubian Complex. Until recently, this technocomplex was found exclusively in northeastern Africa; however, archaeological surveys conducted across the Arabian Peninsula in the last decade have expanded the known distribution of this technological phenomenon. Since 2009, researchers from separate archaeological missions have mapped sites yielding Nubian cores and debitage, and by extension Nubian technology, in the southern, central and northernmost parts of the Arabia Peninsula. Nubian Complex artifacts in central and southern Arabia were made using different raw materials: in Al-Kharj (central Saudi Arabia Middle Paleolithic industries were made exclusively on quartzite, while in Dhofar (southern Oman chert was the only knappable material available for use. Given these differences, we sought to examine the influence of raw material variability on core morphology and size. Contrary to initial hypothesis, this study finds that the differences recorded are not a function of raw material properties. In both areas, Nubian cores were reduced using the same technological systems producing a set of preferential blanks. Rather, the recorded differences from raw material constrains were primarily due to knapping accidents, which occur in higher proportions at quartzite-based assemblages from Al-Kharj (specifically the siret fracture compared with the chert assemblages from Dhofar. In sum, we argue that raw material had little effect on Nubian Levallois core technology and was not a constraint on Nubian Complex artisans.

  18. Origin and age of the Volcanic Rocks of Tláloc Volcano, Sierra Nevada, Central Mexico

    Science.gov (United States)

    Meier, M.; Grobéty, B.; Arce, J. L.; Rueda, H.

    2007-05-01

    The Tláloc volcano (TV) is a 4125 m high stratovolcano of the Trans Mexican Volcanic Belt (TMVB) and is located in the northern end of the N-S trending Sierra Nevada, 30 km NE of Mexico City. Few data on the petrological and temporal evolution of TV have been published to date. Recently dated deposits gave ages between 32'000 and 34'500±500 years BP (Huddart and Gonzalez, 2004). Mapping and sampling of extrusive rocks in the summit region of TV revealed a dome structure with radiating lava flows consisting of dacitic rocks containing plagioclase and hornblende phenocrysts. Some flows, however, seem to be associated with a collapse structure E of the main summit. Crossing relationships indicate that this structure is older (“Paleo Tláloc”). A stratigraphy of the pyroclastic deposits was established along the northern slope of TV. From the numerous pyroclastic flows, separated by paleosoils and fluviatile deposits, only two pumice and one block and ash flow (BAF) have regional extent. Their thickness - distance relationship and their granulometry point to major explosive events. A carbonized wood sample from the BAF deposit gave ages similar to the previous ages (33'180±550 yr BP and 23'170±270 yr BP), a sample from a pyroclastic flow gave even a younger age (16'620±110 yr BP), suggesting that TV remained active also after the volcanoes Iztaccíhuatl and Popocatépetl further to the South started their activity. Based on these preliminary data it may be necessary to reconsider the accepted scenario of the temporal evolution of the central section of the TMVB, which assumes that the activity migrates from North to South with time. Huddart, D. and Gonzalez, S., 2004. Pyroclastic flows and associated sediments, Tláloc-Telapón, piedmont fringe of the eastern basin of Mexico. In: G.J. Aguirre-Diaz, Macías, J.L., and Siebe, C., (Editor), Penrose Conference. UNAM, Metepec, Puebla, Mexico, pp. 35.

  19. Application of chromium stable isotopes to the evaluation of Cr(VI) contamination in groundwater and rock leachates from central Euboea and the Assopos basin (Greece)

    DEFF Research Database (Denmark)

    Economou-Eliopoulos, Maria; Frei, Robert; Atsarou, Cathy

    2014-01-01

    , stable chromium isotopes (expressed as δ53Cr values) were measured in groundwater and leachates in order to identify potential sources for Cr-contamination. The higher Cr(VI) concentrations in soil leachates compared to those in the rock pulp leachates potentially can be explained by the presence......Major and trace elements (a) in groundwater, ultramafic rocks from natural outcrops and soil samples from cultivated sites of Central Euboea and Assopos basin, and (b) in experimentally produced laboratory water leachates of rocks and soils were investigated by SEM/EDS, XRD and ICP/MS. In addition......(III). Using a Rayleigh distillation model and different fractionation factors of Cr(VI) reduction valid for aqueous Fe(II) and Fe(II)-bearing minerals, we calculate that more than ~ 53%, but maximum ~ 94%, of the originally mobile Cr(VI) pool was reduced to immobile Cr(III) in the waters investigated...

  20. Deglacial and Holocene vegetation and climatic changes in the southern Central Mediterranean from a direct land–sea correlation

    Directory of Open Access Journals (Sweden)

    S. Desprat

    2013-03-01

    Full Text Available Despite a large number of studies, the long-term and millennial to centennial-scale climatic variability in the Mediterranean region during the last deglaciation and the Holocene is still debated, including in the southern Central Mediterranean. In this paper, we present a new marine pollen sequence (core MD04-2797CQ from the Siculo-Tunisian Strait documenting the regional vegetation and climatic changes in the southern Central Mediterranean during the last deglaciation and the Holocene. The MD04-2797CQ marine pollen sequence shows that semi-desert plants dominated the vegetal cover in the southern Central Mediterranean between 18.2 and 12.3 ka cal BP, indicating prevailing dry conditions during the deglaciation, even during the Greenland Interstadial (GI-1. Across the transition Greenland Stadial (GS-1 – Holocene, Asteraceae-Poaceae steppe became dominant till 10.1 ka cal BP. This record underlines with no chronological ambiguity that even though temperatures increased, deficiency in moisture availability persisted into the early Holocene. Temperate trees and shrubs with heath underbrush or maquis expanded between 10.1 and 6.6 ka, corresponding to Sapropel 1 (S1 interval, while Mediterranean plants only developed from 6.6 ka onwards. These changes in vegetal cover show that the regional climate in southern Central Mediterranean was wetter during S1 and became drier during the mid- to late Holocene. Wetter conditions during S1 were likely due to increased winter precipitation while summers remained dry. We suggest, in agreement with published modeling experiments, that the early Holocene increased melting of the Laurentide Ice Sheet in conjunction with weak winter insolation played a major role in the development of winter precipitation maxima in the Mediterranean region in controlling the strength and position of the North Atlantic storm track. Finally, our data provide evidence for centennial-scale vegetation and climatic changes in the

  1. Pluri-decadal (1955-2014) evolution of glacier-rock glacier transitional landforms in the central Andes of Chile (30-33° S)

    Science.gov (United States)

    Monnier, Sébastien; Kinnard, Christophe

    2017-08-01

    Three glacier-rock glacier transitional landforms in the central Andes of Chile are investigated over the last decades in order to highlight and question the significance of their landscape and flow dynamics. Historical (1955-2000) aerial photos and contemporary (> 2000) Geoeye satellite images were used together with common processing operations, including imagery orthorectification, digital elevation model generation, and image feature tracking. At each site, the rock glacier morphology area, thermokarst area, elevation changes, and horizontal surface displacements were mapped. The evolution of the landforms over the study period is remarkable, with rapid landscape changes, particularly an expansion of rock glacier morphology areas. Elevation changes were heterogeneous, especially in debris-covered glacier areas with large heaving or lowering up to more than ±1 m yr-1. The use of image feature tracking highlighted spatially coherent flow vector patterns over rock glacier areas and, at two of the three sites, their expansion over the studied period; debris-covered glacier areas are characterized by a lack of movement detection and/or chaotic displacement patterns reflecting thermokarst degradation; mean landform displacement speeds ranged between 0.50 and 1.10 m yr-1 and exhibited a decreasing trend over the studied period. One important highlight of this study is that, especially in persisting cold conditions, rock glaciers can develop upward at the expense of debris-covered glaciers. Two of the studied landforms initially (prior to the study period) developed from an alternation between glacial advances and rock glacier development phases. The other landform is a small debris-covered glacier having evolved into a rock glacier over the last half-century. Based on these results it is proposed that morphological and dynamical interactions between glaciers and permafrost and their resulting hybrid landscapes may enhance the resilience of the mountain cryosphere

  2. Pluri-decadal (1955–2014 evolution of glacier–rock glacier transitional landforms in the central Andes of Chile (30–33° S

    Directory of Open Access Journals (Sweden)

    S. Monnier

    2017-08-01

    Full Text Available Three glacier–rock glacier transitional landforms in the central Andes of Chile are investigated over the last decades in order to highlight and question the significance of their landscape and flow dynamics. Historical (1955–2000 aerial photos and contemporary (> 2000 Geoeye satellite images were used together with common processing operations, including imagery orthorectification, digital elevation model generation, and image feature tracking. At each site, the rock glacier morphology area, thermokarst area, elevation changes, and horizontal surface displacements were mapped. The evolution of the landforms over the study period is remarkable, with rapid landscape changes, particularly an expansion of rock glacier morphology areas. Elevation changes were heterogeneous, especially in debris-covered glacier areas with large heaving or lowering up to more than ±1 m yr−1. The use of image feature tracking highlighted spatially coherent flow vector patterns over rock glacier areas and, at two of the three sites, their expansion over the studied period; debris-covered glacier areas are characterized by a lack of movement detection and/or chaotic displacement patterns reflecting thermokarst degradation; mean landform displacement speeds ranged between 0.50 and 1.10 m yr−1 and exhibited a decreasing trend over the studied period. One important highlight of this study is that, especially in persisting cold conditions, rock glaciers can develop upward at the expense of debris-covered glaciers. Two of the studied landforms initially (prior to the study period developed from an alternation between glacial advances and rock glacier development phases. The other landform is a small debris-covered glacier having evolved into a rock glacier over the last half-century. Based on these results it is proposed that morphological and dynamical interactions between glaciers and permafrost and their resulting hybrid landscapes may enhance the

  3. Unusual Chemistry of the Miocene Central Basin and Range: zr and LREE Enriched Mafic Rocks of the Lucy Gray and Mccullough Mountains, Nevada

    Science.gov (United States)

    Johnsen, R. L.; Smith, E. I.

    2011-12-01

    The dominantly intermediate mid-Miocene (ca. 16-12 Ma) volcanic section in the northern and central McCullough Range of the Basin and Range Province, Nevada, typifies igneous rocks in similar-aged, adjacent mountain ranges (e.g., the Highland Range and the Eldorado Mountains). Calc-alkaline andesite to dacite domes, flows, and related pyroclastic materials dominate while rhyolite and basalt are volumetrically minor constituents. These rocks have the typical "arc" chemical signature prevalent in subduction zones and in pre-extensional Basin and Range igneous rocks (Zr, Nb, Ti depletions, Beer Bottle Pass Granite; and, perhaps most intriguing, 3) the ~1.4 Ga Sulphide Queen carbonatite and age-equivalent shonkinite, syenite, and granite of Mountain Pass. Shonkinites are well known for their extreme LREE enrichment and these in particular contain up to 1000 ppm Zr as well. Could a small amount of contamination of a highly enriched crustal rock such as shonkinite or syenite with a more normal OIB-like basaltic melt account for the odd character of these Miocene rocks? Or is it more likely indicative of an unusually enriched LM source?

  4. Influence of elevation and forest type on community assemblage and species distribution of shrews in the central and southern Appalachian mountains

    Science.gov (United States)

    W. Mark Ford; Timothy S. McCay; Michael A. Menzel; W. David Webster; Cathryn H. Greenberg; John F. Pagels; Joseph F. Merritt; Joseph F. Merritt

    2005-01-01

    We analyzed shrew community data from 398,832 pitfall trapnights at 303 sites across the upper Piedmont, Blue Ridge, northern Ridge and Valley, southern Ridge and Valley, Cumberland Plateau and Allegheny Mountains and Plateau sections of the central and southern Appalachian Mountains from Alabama to Pennsylvania. The objectives of our research were to describe regional...

  5. Influence of elevation and forest type on community assemblage and species distribution of shrews in the central and southern Appalachian Mountains

    Science.gov (United States)

    W. Mark Ford; Timothy S. McCay; Michael A. Menzel; W. David Webster; Cathryn H. Greenberg; John F. Pagels; Joseph F. Merritt

    2006-01-01

    We analyzed shrew community data from 398,832 pitfall trapnights at 303 sites across the upper Piedmont, Blue Ridge, northern Ridge and Valley, southern Ridge and Valley, Cumberland Plateau and Allegheny Mountains and Plateau sections of the central and southern Appalachian Mountains from Alabama to Pennsylvania. The objectives of our research were to describe regional...

  6. Influence of elevation and forest type on community assemblage and species distribution of shrews in the central and southern Appalachian mountains

    Science.gov (United States)

    W. Mark Ford; Timothy S. McCay; Michael A. Menzel; W. David Webster; Cathryn H. Greenberg; John F. Pagels; Joseph F. Merritt

    2005-01-01

    We analyzed shrew community data from 398,832 pitfall trapnights at 303 sites across the upper Piedmont, Blue ridge, northern Ridge and Valley, southern Ride and Valley, Cumberland Plateau and Allegheny Mountains and Plateau sections of the central and southern Appalachian Mountains from Alabama to Pennsylvania. The objectives of our research were to describe regional...

  7. Examining the Effects of Anthropogenic Emissions on Isoprene-Derived Secondary Organic Aerosol Formation During the 2013 Southern Oxidant and Aerosol Study (SOAS) at the Look Rock, Tennessee, Ground Site

    Science.gov (United States)

    A suite of offline and real-time gas- and particle-phase measurements was deployed atLook Rock, Tennessee (TN), during the 2013 Southern Oxidant and Aerosol Study (SOAS) to examine the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol (SOA) formatio...

  8. Pluri-decadal (1955–2014) evolution of glacier–rock glacier transitional landforms in the central Andes of Chile (30–33° S)

    OpenAIRE

    S. Monnier; C. Kinnard

    2017-01-01

    Three glacier–rock glacier transitional landforms in the central Andes of Chile are investigated over the last decades in order to highlight and question the significance of their landscape and flow dynamics. Historical (1955–2000) aerial photos and contemporary (> 2000) Geoeye satellite images were used together with common processing operations, including imagery orthorectification, digital elevation model generation, and image feature tracking. At each site...

  9. Plume-subduction interaction in southern Central America: Mantle upwelling and slab melting

    Science.gov (United States)

    Gazel, Esteban; Hoernle, Kaj; Carr, Michael J.; Herzberg, Claude; Saginor, Ian; den Bogaard, Paul van; Hauff, Folkmar; Feigenson, Mark; Swisher, Carl

    2011-01-01

    The volcanic front in southern Central America is well known for its Galapagos OIB-like geochemical signature. A comprehensive set of geochemical, isotopic and geochronological data collected on volumetrically minor alkaline basalts and adakites were used to better constrain the mantle and subduction magma components and to test the different models that explain this OIB signature in an arc setting. We report a migration of back-arc alkaline volcanism towards the northwest, consistent with arc-parallel mantle flow models, and a migration towards the southeast in the adakites possibly tracking the eastward movement of the triple junction where the Panama Fracture Zone intersects the Middle America Trench. The adakites major and trace element compositions are consistent with magmas produced by melting a mantle-wedge source metasomatized by slab derived melts. The alkaline magmas are restricted to areas that have no seismic evidence of a subducting slab. The geochemical signature of the alkaline magmas is mostly controlled by upwelling asthenosphere with minor contributions from subduction components. Mantle potential temperatures calculated from the alkaline basalt primary magmas increased from close to ambient mantle (~ 1380-1410 °C) in the Pliocene to ~ 1450 °C in the younger units. The calculated initial melting pressures for these primary magmas are in the garnet stability field (3.0-2.7 GPa). The average final melting pressures range between 2.7 and 2.5 GPa, which is interpreted as the lithosphere-asthenosphere boundary at ~ 85-90 km. We provide a geotectonic model that integrates the diverse observations presented here. The slab detached after the collision of the Galapagos tracks with the arc (~ 10-8 Ma). The detachment allowed hotter asthenosphere to flow into the mantle wedge. This influx of hotter asthenosphere explains the increase in mantle potential temperatures, the northwest migration in the back-arc alkaline lavas that tracks the passage of the

  10. Estimation of real evapotranspiration and its variation in Mediterranean landscapes of central-southern Chile

    Science.gov (United States)

    Olivera-Guerra, L.; Mattar, C.; Galleguillos, M.

    2014-05-01

    Evapotranspiration (ETd) is a key controller in the ecohydrological processes of semi-arid landscapes. This is the case of the dry land in Chile's central-southern zone, where forestry, farming and livestock activities must adapt to precipitation with considerable year-on-year variations. In this study, the spatial distribution of ETd was estimated in relation to the land use map and physical parameters of the soil. The ETd was estimated through the Simplified Surface Energy Balance Index (S-SEBI) using data from weather stations and remote data provided by the ASTER and MODIS sensors for November 2004 and 2006, respectively. The spatial variability of ETd was compared among different plant types, soil textural classes and depths using non-parametric statistical tests. In this comparison, the highest rates of ETd were obtained in the forest covers with values of 7.3 ± 0.8 and 8.4 ± 0.8 mm d-1 for 2004 and 2006, respectively. The lowest values were estimated for pastures and shrublands with values of 3.5 ± 1.2 mm d-1 and for crops with rates of 4.4 ± 1.6 mm d-1. Comparison of the ETd of the native forest covers and plantations of exotic species showed statistically significant differences; however, no great variation was noted, at least in the study months. Additionally, the highest rates of ETd were found in the clay loam textures (6.0 ± 1.8 and 6.4 ± 2.0 mm d-1) and the lowest rates in the sandy loam soils (3.7 ± 1.6 and 3.9 ± 1.6 mm d-1) for 2004 and 2006, respectively. The results enable analysis of the spatial patterns of the landscape in terms of the relation between water consumption, ET and the biophysical characteristics of a Mediterranean ecosystem. These results form part of the creation of tools useful in the optimization of decision-making for the management and planning of water resources and soil use in territories with few measuring instruments.

  11. Late Cenozoic acceleration of erosion in the Southern Central Andes revealed by low-temperature thermochronology

    Science.gov (United States)

    Franziska Stalder, Nadja; Herman, Frédéric; Reiners, Peter W.; Aguilar, German

    2017-04-01

    /or glaciations in the area south of 33°S latitude could thus explain the intensified erosion in the Plio-Pleistocene. Coinciding with decreasing topography and a narrowing of the Andean mountain belt, these preliminary results may indicate a climatic control on exhumation, and potentially tectonics, in the Southern Central Andes.

  12. Ethnophytotherapeutical research in the high Molise region (Central-Southern Italy

    Directory of Open Access Journals (Sweden)

    Lucchese Fernando

    2008-03-01

    Full Text Available Abstract Background In the years 2003–2005 research was carried out concerning ethno-medicine in the high Molise (central- southern Italy, a region that has been the object of very little investigation from the ethnobotanical point of view. Upper Molise is a continuation of the mountain profiles of the Abruzzi Appenines: a series of hills, steep slopes and deep fluvial valleys making communications difficult. Primordial traditions (e.g. harvest feasts are typical of the region. Methods Field data were collected through open interviews in the field. These were conducted on both an individual and group level, fresh plants gathered from surrounding areas being displayed. In other cases, individual interviews were conducted by accompanying the person involved to the places where they perform their activities (for example, in the woods with woodcutters, kitchen gardens and fields with housewives, pastures with shepherds, etc.. In total 54 individuals were interviewed. Results Data of 70 taxa belonging to 39 families were gathered. Among the species, 64 are used in human therapy, 5 as insect repellents, 11 in veterinary medicine, 1 to keep eggs and cheeses and 4 for magic purposes. The most important findings in ethno-medicine relate to the lichen Lobaria pulmonaria (L. Hoffm. (wounds and to some vascular plant species: Asplenium trichomanes L. and Ceterach officinarum Willd. (to regularize menstruation, Cyclamen hederifolium (chilblains, Centaurium erythraea Rafn. and Pulmonaria apennina Cristof. & Puppi (bruises, while in the ethno-veterinary field, we have Valeriana officinalis L. (wounds sustained by mules. Also worthy of note, given the isolation of the area, is the number of plants used to protect foodstuffs from parasites, among which Allium sativum L. and Capsicum frutescens L. Conclusion The research revealed a deep-rooted and widespread habit of husbanding the family's resources. Whilst isolation and snowfalls contributed to the widespread

  13. Nursing and midwifery regulatory reform in east, central, and southern Africa: a survey of key stakeholders

    Science.gov (United States)

    2013-01-01

    Background In sub-Saharan Africa, nurses and midwives provide expanded HIV services previously seen as the sole purview of physicians. Delegation of these functions often occurs informally by shifting or sharing of tasks and responsibilities. Normalizing these arrangements through regulatory and educational reform is crucial for the attainment of global health goals and the protection of practitioners and those whom they serve. Enacting appropriate changes in both regulation and education requires engagement of national regulatory bodies, but also key stakeholders such as government chief nursing officers (CNO), professional associations, and educators. The purpose of this research is to describe the perspectives and engagement of these stakeholders in advancing critical regulatory and educational reform in east, central, and southern Africa (ECSA). Methods We surveyed individuals from these three stakeholder groups with regard to task shifting and the challenges related to practice and education regulation reform. The survey used a convenience sample of nursing and midwifery leaders from countries in ECSA who convened on 28 February 2011, for a meeting of the African Health Profession Regulatory Collaborative. Results A total of 32 stakeholders from 13 ECSA countries participated in the survey. The majority (72%) reported task shifting is practiced in their countries; however only 57% reported their national regulations had been revised to incorporate additional professional roles and responsibilities. Stakeholders also reported different roles and levels of involvement with regard to nursing and midwifery regulation. The most frequently cited challenge impacting nursing and midwifery regulatory reform was the absence of capacity and resources needed to implement change. Discussion While guidelines on task shifting and recommendations on transforming health professional education exist, this study provides new evidence that countries in the ECSA region face

  14. Interaction between active tectonics, erosion and diapirism, a case study from Habble-Rud in Southern Central Alborz (Northern Iran)

    Science.gov (United States)

    Jaberi, Maryam; Ghassemi, Mohammad R.; Shayan, Siavosh; Yamani, Mojtaba; Zamanzadeh, Seyed Mohammad

    2018-01-01

    The Alborz mountain chain is a region of active deformation within the Arabia-Eurasia continental collision zone. The southern part of central Alborz Mountains, in the north of Iran, represents complex tectonics because it is located at the border of two developing continental sedimentary basins between southern central Alborz and Central Iran. An arid and semi-arid climate, a large extent of Quaternary sediments, rugged topography, salt domes and faults with historical seismicity influence the Habble-Rud River catchment. In the present research, a number of tectonic geomorphologic indices were extracted from satellite imagery and 10 m DEM (digital elevation model) data in order to identify relative tectonic activity within the basin. The indices include: stream length-gradient index (Sl), drainage basin asymmetry (Af), index of mountain front sinuosity (Smf), hypsometric integral (Hi), index of drainage basin shape (Bs), ratio of valley-floor width to valley height (Vf), and fault density (Fd). Due to the presence of heterogeneous indices for all sections of the catchment causing large extension of Habble-Rud (3260 km2), all of the variables such as extremely erodible formations, faults and folds and salt tectonics on the Southern part; were put into a matrix table. As a new approach, the variables were put into the SAW (simple additive model) model as one of MADM (multi-attribute decision-making models) techniques. The study area was divided into four regions according to the values of SAW. These classes include very high (%11), high (48.3%), moderate (34.7%), and low activity (3.4%). The result of the model suggests that the study area is located on a changing tectonic trend in central Alborz from NW-SE to NE-SW. The regions with high relative tectonic activity in HR catchment correspond to the active Garmsar and Sorkhe-Kalout faults and diapirs.

  15. Curie isotherm depth from aeromagnetic data constraining shallow heat source depths in the central Aeolian Ridge (Southern Tyrrhenian Sea, Italy)

    Science.gov (United States)

    De Ritis, R.; Ravat, D.; Ventura, G.; Chiappini, M.

    2013-04-01

    The Salina, Lipari, and Vulcano volcanic ridge and the surrounding sea sectors (Aeolian Archipelago, Southern Tyrrhenian Sea, Italy) are characterized by vents responsible for a recent (Salina volcanic ridge allows us to constrain the Curie isotherm depth. The elevated portion of the isotherm is between 2 and 3 km below Salina and Vulcano and about 1 km below Lipari. The Curie depth results in the context of other geological and geophysical evidence suggest that the rise of the Curie isotherm is mainly due to the occurrence of shallow heat sources such as magma ponds and associated hydrothermal systems. The short-wavelength magnetic anomaly field reflects magnetic contrasts from highly magnetized volcanic bodies, low-magnetization sediments, and hydrothermally altered rocks. Borehole temperature data verify the Curie temperature derived from the magnetic methods on the island of Vulcano. We conclude that the whole Vulcano, Lipari, and Salina volcanic ridge is active and should be monitored.

  16. Nest predation on birds that nest in rock cavities in a tropical limestone forest of southern China

    Directory of Open Access Journals (Sweden)

    Aiwu Jiang

    2017-04-01

    Full Text Available High nest predation is often found in tropical birds, though data from tropical limestone regions are lacking. In a limestone karst rainforest of south China, two species of babblers breed in rock cavities in different seasonal periods: the endangered Nonggang Babbler (Stachyris nonggangensis breeds in May, like most birds, and the common Streaked Wren Babbler (Napothera brevicaudata breeds in March. We tested the hypothesis that nest predation varied by nesting period using an artificial nest experiment. We used natural rock cavities that varied in their distance to the forest edge, checked nests at different intervals and measured characteristics of cavity location. We found nest predation to be much higher in May (65 of 99 nests than March (14 of 83; predation tended to be higher when nests were visited only once, but no other factor significantly influenced the result. The higher predation rate during warmer weather, and the fact that eggs disappeared mostly at once, yet predators were not detected on infrared nest cameras, suggests that snakes could be important predators; further research is needed to confirm this hypothesis. We conclude that the aberrant nesting period of the Streaked Wren Babbler may be a strategy to escape nest predation.

  17. Phenology and recruitment of Caryocar costaricense (Caryocaceae, an endemic tree species of Southern Central America

    Directory of Open Access Journals (Sweden)

    Silvia Solís

    2009-09-01

    Full Text Available Basic aspects of the reproductive biology are largely unknown for most tropical tree species, although they are important elements to understand the impacts of anthropogenic activities as logging and forest fragmentation on these populations. In this study, data are presented on leaf and reproductive phenology, fruit production and seedling demography of a population of an endemic tree species of Southern Central America, Caryocar costaricense. This species has been affected by selective logging and forest fragmentation of its habitat. Phenology was studied by observation of 15-22 tree crowns during two reproductive periods (2003 and 2005. Circular plots were established around 11 adult trees to count the number of fallen fruits and seedlings during three years (2003, 2004, 2005. Although reproductive phenology is restricted to the short dry season in this species, seed germination occurred year-round. Fruit and seedling production shows a strong inter-individual variation within the study populations, with two large trees producing nearly 50%-70% of the fruits and seedlings during two years. Most of the seeds that fall beneath the tree crown are covered by litterfall or removed by fauna. We found evidence that many of these seeds become part of a seed bank in the forest floor. Because of the observed reproductive dominance of few large trees in these populations, we propose that selective logging on reproductive trees can severely impact the recruitment of this species. Rev. Biol. Trop. 57 (3: 771-780. Epub 2009 September 30.Los aspectos básicos de la biología reproductiva de árboles tropicales son en su mayoría desconocidos, aunque son conocimientos esenciales para entender el impacto de actividades antropogénicas como la tala selectiva y la fragmentación de bosques. En este estudio se presentan datos sobre la fenología foliar y reproductiva, la producción de frutos, y la demografía de plántulas de una población de Caryocar

  18. Cryospheric Dynamics in the Central Chilean Andes: Multi-decadal Reconstruction and Multi-annual Monitoring of Rock Glaciers and a Debris-covered Glacier

    Science.gov (United States)

    Bodin, X.; Rojas, F.; Brenning, A.

    2009-05-01

    In the semiarid Central Chilean Andes at 33.5°S, permafrost is widely present above 3500-4000 m a.s.l., especially in the form of ice-rich debris accumulations such as rock glaciers. While Chilean rock glacier are among the largest known rock glaciers, glaciers are mostly restricted to the highest summits and are affected by a significant retreat during the last decades. Rock glaciers display a characteristic morphology produced by the deep-seated steady-state creeping of their permafrost body, and they are of great geomorphic and hydrological importance in poorly glaciated mountains. Their response to Global Warming is however still poorly understood. Our study area in the Laguna Negra catchment provides up to two-thirds of the drinking water supplies to Chile's capital Santiago (5.5 million inhabitants) during the dry summer months. We investigate the multi-decadal and multi-annual dynamics of a complex cryospheric system composed of a rock glacier and debris-covered glacier. We use aerial photogrammetry to produce diachronic orthophotos and high-resolution digital elevation models of 1956 and 1996, and to detect changes in cryospheric features such as glacier retreat, thermokarst development and rock glacier creep. Surface dynamics on rock glacier transects are furthermore analyzed using differential GPS measurements (2004-2008), indicating horizontal surface displacement rates between 20 and 130 cm/yr. Ground temperatures monitored in 2003/04 with miniature data loggers between 2500 and 4000 m a.s.l. in combination with regional meteorological measurements provide further insight into periglacial process environments in the Andes of Santiago, including information on frost penetration depth, influence of snow cover, and altitudinal gradients. Ongoing research in the Laguna Negra area include a spatially distributed ground thermal monitoring program and, for the first time in the Andes, terrestrial laser scanning of rock glaciers. The cryospheric monitoring

  19. Tourmaline occurrences within the Penamacor-Monsanto granitic pluton and host-rocks (Central Portugal): genetic implications of crystal-chemical and isotopic features

    Science.gov (United States)

    da Costa, I. Ribeiro; Mourão, C.; Récio, C.; Guimarães, F.; Antunes, I. M.; Ramos, J. Farinha; Barriga, F. J. A. S.; Palmer, M. R.; Milton, J. A.

    2014-04-01

    Tourmalinization associated with peraluminous granitic intrusions in metapelitic host-rocks has been widely recorded in the Iberian Peninsula, given the importance of tourmaline as a tracer of granite magma evolution and potential indicator of Sn-W mineralizations. In the Penamacor-Monsanto granite pluton (Central Eastern Portugal, Central Iberian Zone), tourmaline occurs: (1) as accessory phase in two-mica granitic rocks, muscovite-granites and aplites, (2) in quartz (±mica)-tourmaline rocks (tourmalinites) in several exocontact locations, and (3) as a rare detrital phase in contact zone hornfels and metapelitic host-rocks. Electron microprobe and stable isotope (δ18O, δD, δ11B) data provide clear distinctions between tourmaline populations from these different settings: (a) schorl-oxyschorl tourmalines from granitic rocks have variable foititic component (X□ = 17-57 %) and Mg/(Mg + Fe) ratios (0.19-0.50 in two-mica granitic rocks, and 0.05-0.19 in the more differentiated muscovite-granite and aplites); granitic tourmalines have constant δ18O values (12.1 ± 0.1 ‰), with wider-ranging δD (-78.2 ± 4.7 ‰) and δ11B (-10.7 to -9.0 ‰) values; (b) vein/breccia oxyschorl [Mg/(Mg + Fe) = 0.31-0.44] results from late, B- and Fe-enriched magma-derived fluids and is characterized by δ18O = 12.4 ‰, δD = -29.5 ‰, and δ11B = -9.3 ‰, while replacement tourmalines have more dravitic compositions [Mg/(Mg + Fe) = 0.26-0.64], close to that of detrital tourmaline in the surrounding metapelitic rocks, and yield relatively constant δ18O values (13.1-13.3 ‰), though wider-ranging δD (-58.5 to -36.5 ‰) and δ11B (-10.2 to -8.8 ‰) values; and (c) detrital tourmaline in contact rocks and regional host metasediments is mainly dravite [Mg/(Mg + Fe) = 0.35-0.78] and oxydravite [Mg/(Mg + Fe) = 0.51-0.58], respectively. Boron contents of the granitic rocks are low (Monsanto pluton, either as direct tourmaline precipitation in cavities and fractures crossing the

  20. Isotopic Studies of the Guerrero Composite Terrane, West-Central Mexico: Implications for Provenance of Crustal Rocks and Ore Metals

    Science.gov (United States)

    Potra, A.; Macfarlane, A. W.; Salters, V. J.; Sachi-Kocher, A.

    2010-12-01

    New Pb, Sr, and Nd isotope analyses of various crustal units and ores from the Guerrero terrane are presented in order to gain insight into their provenance. Mesozoic basement rocks from the Arteaga Complex and Tejupilco metamorphic suite contain radiogenic Pb relative to bulk earth models (206Pb/204Pb between 18.701 and 19.256, 207Pb/204Pb between 15.623 and 15.693, and 208Pb/204Pb between 38.694 and 39.216), plotting to the right of the average Pb crust evolution curve of Stacey and Kramers (1975). The isotopic compositions of Pb in these rocks are substantially more radiogenic than published data on high-grade metamorphic rocks from the Grenvillian-age Oaxaca terrane, but are similar to Paleozoic basement rocks of the Mixteca terrane. Sr and Nd isotope data suggest that the basement rocks of the Guerrero terrane partly originated from ocean-floor rocks which were overlain by sediments derived from a cratonic terrane, possibly represented by the metamorphic complexes of the Oaxaca or Mixteca terranes. Lead isotope ratios of Cretaceous sedimentary rocks of the Zihuatanejo and Huetamo Sequences define two different clusters, with the Zihuatanejo Sequence units shifted to more radiogenic values (206Pb/204 between 18.763 and 19.437, 207Pb/204Pb between 15.580 and 15.643, and 208Pb/204Pb between 38.510 and 38.892). Samples from the Huetamo Sequence are less radiogenic than the metamorphic basement, with Pb isotope ratios between 18.630 and 18.998 for 206Pb/204, 15.563 and 15.641 for 207Pb/204Pb, and 38.369 and 38.610 for 208Pb/204Pb. They plot close to the radiogenic end of the MORB field, suggesting a possible mixing line between the basement rocks and the MORB component. Lead isotope ratios of Tertiary intrusive rocks from La Verde, El Malacate, and La Esmeralda resemble the orogene reservoir in the plumbotectonics model of Zartman and Doe (1981). Plutonic rocks from La Verde show the most radiogenic Pb compositions, suggesting a significant influence of old

  1. Distribution of manganese nodules, rocks and sediments in the Central Indian Ocean Basin: Factors influencing performance of mining system

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, R.; Sudhakar, M.; Iyer, S.D.

    variable depth of burial at different locations. Rock exposures, as observed in the photographs, have 6-100% coverage on the seafloor. Morphologically, the CIOB comprises abyssal hills and seamounts, as well as valleys and abyssal plains. The topographic...

  2. Seroprevalence study of Toscana virus and viruses belonging to the Sandfly fever Naples antigenic complex in central and southern Italy.

    Science.gov (United States)

    Marchi, Serena; Trombetta, Claudia M; Kistner, Otfried; Montomoli, Emanuele

    Sandfly fever viruses are transmitted by the bite of phlebotomine sandflies; serotypes sandfly fever Naples virus, sandfly fever Sicilian virus and sandfly fever Cyprus virus cause febrile illness, whereas Toscana virus (TOSV) may cause neuroinvasive infections. Although TOSV is an important cause of aseptic meningitis in central and southern Italy, in many cases the infection is asymptomatic, leading to underestimation of the actual spread of the virus. This serosurvey aimed to assess the seroprevalence of TOSV in a random population in Siena (Tuscany, central Italy) in 2003-2004 and 2013-2014 and Bari (Apulia, southern Italy) in 2004 and 2015. 2132 serum samples were tested for the presence of anti-TOSV/SFNV IgG by means of ELISA and IFA commercial tests. Seroprevalence rates were compared in the two cities and over a ten-year period in the same city. Seroprevalence results in the Siena population (22.95% in 2003-2004 vs 26.75% in 2013-2014) confirmed the endemic circulation of TOSV and closely related viruses in central Italy, without major changes over the last decade, while no significant prevalence was observed in Bari (2.90% in 2004 vs 1.85% in 2015). Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Numerical modelling of gas-water-rock interactions in volcanic-hydrothermal environment: the Ischia Island (Southern Italy) case study.

    Science.gov (United States)

    Di Napoli, R.; Federico, C.; Aiuppa, A.; D'Antonio, M.; Valenza, M.

    2012-04-01

    Hydrothermal systems hosted within active volcanic systems represent an excellent opportunity to investigate the interactions between aquifer rocks, infiltrating waters and deep-rising magmatic fluids, and thus allow deriving information on the activity state of dormant volcanoes. From a thermodynamic perspective, gas-water-rock interaction processes are normally far from equilibrium, but can be represented by an array of chemical reactions, in which irreversible mass transfer occurs from host rock minerals to leaching solutions, and then to secondary hydrothermal minerals. While initially developed to investigate interactions in near-surface groundwater environments, the reaction path modeling approach of Helgeson and co-workers can also be applied to quantitative investigation of reactions in high T-P environments. Ischia volcano, being the site of diffuse hydrothermal circulation, is an ideal place where to test the application of reaction-path modeling. Since its last eruption in 1302 AD, Ischia has shown a variety of hydrothermal features, including fumarolic emissions, diffuse soil degassing and hot waters discharges. These are the superficial manifestation of an intense hydrothermal circulation at depth. A recent work has shown the existence of several superposed aquifers; the shallowest (near to boiling) feeds the numerous surface thermal discharges, and is recharged by both superficial waters and deeper and hotter (150-260°C) hydrothermal reservoir fluids. Here, we use reaction path modelling (performed by using the code EQ3/6) to quantitatively constrain the compositional evolution of Ischia thermal fluids during their hydrothermal flow. Simulations suggest that compositions of Ischia groundwaters are buffered by interactions between reservoir rocks and recharge waters (meteoric fluids variably mixed - from 2 to 80% - with seawater) at shallow aquifer conditions. A CO2 rich gaseous phase is also involved in the interaction processes (fCO2 = 0.4-0.6 bar

  4. Paleomagnetism of Jurassic and Cretaceous rocks in central Patagonia: a key to constrain the timing of rotations during the breakup of southwestern Gondwana?

    Science.gov (United States)

    Geuna, Silvana E.; Somoza, Rubén; Vizán, Haroldo; Figari, Eduardo G.; Rinaldi, Carlos A.

    2000-08-01

    A paleomagnetic study in Jurassic and Cretaceous rocks from the Cañadón Asfalto basin, central Patagonia, indicates the occurrence of about 25-30° clockwise rotation in Upper Jurassic-lowermost Cretaceous rocks, whereas the overlying mid-Cretaceous rocks do not show evidence of rotation. This constrains the tectonic rotation to be related to a major regional unconformity in Patagonia, which in turn seems to be close in time with the early opening of the South Atlantic Ocean. The sense and probably the timing of this rotation are similar to those of other paleomagnetically detected rotations in different areas of southwestern Gondwana, suggesting a possible relationship between these and major tectonic processes related with fragmentation of the supercontinent. On the other hand, the mid-Cretaceous rocks in the region yield a paleopole located at Lat. 87° South, Long. 159° East, A95=3.8°. This pole position is consistent with coeval high-quality paleopoles of other plates when transferred to South American coordinates, implying it is an accurate determination of the Aptian (circa 116 Ma) geomagnetic field in South America.

  5. Rock magnetic properties of the Arunta Block, Central Australia, and their implication for the interpretation of long-wavelength magnetic anomalies

    Science.gov (United States)

    Kelso, Paul R.; Banerjee, Subir K.; Teyssier, Christian

    1993-01-01

    Rock magnetic and petrologic studies of a suite of deep crustal rocks from the Arunta Block of Central Australia reveal that the granulite grade rocks are in general much more magnetic than the amphibolite grade samples irrespective of bulk rock composition. The dominant magnetic mineral in all samples is relatively pure magnetite as determined from thermomagnetic and electron microprobe analysis. The bulk magnetic properties are typical of pseudosingle-domain to multidomain size material. The samples from our study have very large remanences compared to previous crustal magnetic studies, with the granulites having a median natural remanent magnetization of 4.1 A/m and Koenigsberger ratio of 7.2. These remanences are relatively resistant to the thermal demagnetization, with nearly 50 percent of the magnetization remaining after 400 C demagnetization. Thus remanence may contribute significantly to the observed magnetic anomalies, including long-wavelength magnetic anomalies, the source of which resides at depth and therefore at elevated temperature, where a thermoviscous remanant magnetization along the present-day field is likely to dominate.

  6. The density of the rock covering Gran Sasso Laboratories in Central Apennines, Italy by underground gravity measurements

    Science.gov (United States)

    Capuano, P.; De Luca, G.; Di Sena, F.; Gasparini, P.; Scarpa, R.

    1998-05-01

    Various nuclear physics experiments are being carried out in the Istituto Nazionale di Fisica Nucleare Laboratories that have been excavated in the Gran Sasso Massif in the Italian Apennines. These experiments make use of the shield effect provided by a 1400-m-thick rock cover that absorb cosmic rays. It is important to know the real density of the rock cover and the extent of its lateral variation. The density of different sections of the rock cover was determined using the correlation between measured underground gravity data and thickness of the rock cover. Observed gravity was corrected using a 3D model, for the mass deficiency covered by excavation of highway tunnels and the cavities that house the laboratories. The average density of the rock cover was found to be 2720±50 kg m -3. Lateral variations are contained within the uncertainty for most of the sections, except for two sections where densities are lowered by as much as 11% because of the presence of a shallow layer formed by loose Quaternary sediments.

  7. The Southern Yellowjacket, Vespula squamosa (Drury) (Hymenoptera: vespidae) in Guatemala, Central America

    Science.gov (United States)

    Southern yellowjackets, Vespula squamosa (Drury) were collected at sites in Guatemala, in the Departments of Baja Verapaz, El Progresso, and Zacapa. Collection localities ranged in elevation from 500 to 1880 m. These locations were forested, or partially forested with some pasture land and coffee ...

  8. Effects of Date and Frequency of Burning on Southern Bayberry (Myrica cerifera) in Central Louisiana

    Science.gov (United States)

    James D. Haywood; Henry A. Pearson; Harold E. Grelen; Thomas W. Popham

    2000-01-01

    Myrica cerifera (southern bayberry or waxmyrtle) is one of the most common shrubs in the longleaf pine/bluestem forest type in the West Gulf Coastal Plain. During controlled burns, individual plants can burn intensely because the wax coated foliage and fruits are very flammable. However, Myrica cerifera can survive tires on...

  9. Map showing the distribution and characteristics of plutonic rocks in the Tonopah 1 degree by 2 degrees Quadrangle, central Nevada

    Science.gov (United States)

    John, D.A.

    1987-01-01

    Plutonic rocks, mostly granite and granodiorite, are widely distributed in the west two-thirds of the Tonopah 1 degree by 2 degree quadrangle, Nevada. These rocks were systematically studied as part of the Tonopah CUSMAP project. Studies included field mapping, petrographic and modal analyses, geochemical studies of both fresh and altered plutonic rocks and altered wallrocks, and K-Ar and Rb-Sr radiometric dating. Data collected during this study were combined with previously published data to produce a 1:250,000-scale map of the Tonopah quadrangle showing the distribution of individual plutons and an accompanying table summarizing composition, texture, age, and any noted hydrothermal alteration and mineralization effects for each pluton.

  10. A Silurian-early Devonian slab window in the southern Central Asian Orogenic Belt: Evidence from high-Mg diorites, adakites and granitoids in the western Central Beishan region, NW China

    Science.gov (United States)

    Zheng, Rongguo; Xiao, Wenjiao; Li, Jinyi; Wu, Tairan; Zhang, Wen

    2018-03-01

    The Beishan orogenic belt is a key region for deciphering the accretionary processes of the southern Central Asian Orogenic Belt. Here in this paper we present new zircon U-Pb ages, bulk-rock major and trace element, and zircon Hf isotopic data for the Baitoushan, and Bagelengtai plutons in the western Central Beishan region to address the accretionary processes. The Baitoushan pluton consists of quartz diorites, monzonites and K-feldspar granites, with zircon LA-ICP-MS U-Pb ages of 435 Ma, 421 Ma and 401 Ma, respectively. The Baitoushan quartz diorites and quartz monzonites exhibit relatively high MgO contents and Mg# values (63-72), display enrichments in LILEs and LREEs, and exhibit high Ba (585-1415 ppm), Sr (416-570 ppm) and compatible element (such as Cr and Ni) abundances, which make them akin to typical high-Mg andesites. The Baitoushan quartz diorites and quartz monzonites were probably generated by the interaction of subducted oceanic sediment-derived melts and mantle peridotites. The Baitoushan K-feldspar granites are ascribed to fractionated I-type granites with peraluminous and high-K calc-alkaline characteristics. They exhibit positive εHf(t) values (2.43-7.63) and Mesoproterozoic-Neoproterozoic zircon Hf model ages (0.92-1.60 Ga). Those early Devonian granites, including Baitoushan K-feldspar granite and Gongpoquan leucogranites (402 Ma), are derived from melting of the mafic lower crust and/or sediments by upwelling of hot asthenospheric mantle. The Bagelengtai granodiorites exhibit similar geochemical signatures with that of typical adakites, with a zircon SHRIMP U-Pb age of 435 Ma. They exhibit relatively high Sr (502-628 ppm) and Al2O3 (16.40-17.40 wt.%) contents, and low MgO (1.02-1.29 wt.%), Y (3.37-6.94 ppm) and HREEs contents, with relatively high Sr/Y and (La/Yb)N ratios. The Bagelengtai granodiorites were derived from partial melting of subducted young oceanic crust, with significant contributions of subducted sediments, subsequently

  11. The Wenquan ultramafic rocks in the Central East Kunlun Fault zone, Qinghai-Tibet Plateau—crustal relics of the Paleo-Tethys ocean

    Science.gov (United States)

    Jia, Lihui; Meng, Fancong; Feng, Huibin

    2017-11-01

    The Wenquan ultramafic rocks, located in the East Kunlun Orogenic belt in the northeastern part of the Qinghai-Tibet Plateau, consist of dunite, wehrlite, olivine-clinopyroxenite and clinopyroxenite, and exhibit cumulate textures. Olivine from dunite has high Fo (forsterite, 90.0-91.8 wt%) and NiO content (0.15-0.42 wt%). Cr-spinels from all of the rocks in this suite are characterized by high Cr# (100×[Cr/(Cr + Al)], 67-91), low Mg# (100×[Mg/(Mg + Fe2+)], 17-35) and low TiO2 contents (mostly 80) and low-CaO (Proterozoic ophiolites. The Wenquan ophiolite might be a relict of the Paleotethyan ocean, indicating that there were two cycles of oceanic-continental evolution along the Central East Kunlun Fault zone.

  12. Whole-rock and sulfide-mineral geochemical data for samples from volcanogenic massive sulfide deposits of the Bonnifield district, east-central Alaska

    Science.gov (United States)

    Dusel-Bacon, Cynthia; Slack, John F.; Koenig, Alan E.; Foley, Nora K.; Oscarson, Robert L.; Gans, Kathleen D.

    2011-01-01

    This Open-File Report presents geochemical data for outcrop and drill-core samples from volcanogenic massive sulfide deposits and associated metaigneous and metasedimentary rocks in the Wood River area of the Bonnifield mining district, northern Alaska Range, east-central Alaska. The data consist of major- and trace-element whole-rock geochemical analyses, and major- and trace-element analyses of sulfide minerals determined by electron microprobe and laser ablation—inductively coupled plasma—mass spectrometry (LA-ICP-MS) techniques. The PDF consists of text, appendix explaining the analytical methods used for the analyses presented in the data tables, a sample location map, and seven data tables. The seven tables are also available as spreadsheets in several file formats. Descriptions and discussions of the Bonnifield deposits are given in Dusel-Bacon and others (2004, 2005, 2006, 2007, 2010).

  13. Rocks of the Thirtynine Mile volcanic field as possible sources of uranium for epigenetic deposits in central Colorado, USA.

    Science.gov (United States)

    Dickinson, K.A.

    1987-01-01

    The most likely volcanic source rock for uranium in epigenetic deposits of the Tallahassee Creek uranium district and nearby areas is the Wall Mountain Tuff. The widespread occurrence of the Tuff, its high apparent original uranium content, approx 11 ppm, and its apparent loss of uranium from devitrification and other alteration suggest its role in providing that element. An estimate of the original Th/U ratio is based on the present thorium and uranium contents of the basal vitrophyre of the Tuff from Castle Rock Gulch, Hecla Junction and other areas.-from Author

  14. Preliminary evaluation of 30 potential granitic rock sites for a radioactive waste storage facility in southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Boardman, C.R.; Knutson, C.F.

    1978-02-15

    Results of preliminary study are presented which was performed under subtask 2.7 of the NTS Terminal Waste Storage Program Plan for 1978. Subtask 2.7 examines the feasibility of locating a nuclear waste repository in a granitic stock or pluton in southern Nevada near the Nevada Test Site (NTS). It is assumed for the purposes of this study that such a repository cannot be located at NTS. This assumption may or may not be correct. This preliminary report does not identify a particular site as being a suitable location for a repository. Nor does it absolutely eliminate a particular site from further consideration. It does, however, answer the basic question of probable suitability of some of the sites and present a systematic method for site evaluation. Since the findings of this initial study have been favorable, it will be followed by more exhaustive and detailed studies of the original 30 sites and perhaps others. In future studies some of the evaluation criteria used in the preliminary study may be modified or eliminated, and new criteria may be introduced.

  15. Habitat suitability modeling of amphibian species in southern and central China: environmental correlates and potential richness mapping.

    Science.gov (United States)

    Chen, Youhua

    2013-05-01

    Successful wildlife management must take into account suitable habitat areas. Information on the correlation between distribution ranges and environmental conditions would, therefore, improve the efficacy of in-situ conservation of wildlife. In this contribution, correlations between environmental factors and the distribution of 51 amphibians in southern and central China were investigated. Ecological niche factor analysis (ENFA) at a spatial resolution of 1° latitude×1° longitude identified a mixture of climatic and habitat factors as important predictors of the occurrence of individual species. The aims of the present work were (i) to evaluate potential distributions of amphibians based on the suitability of areas; (ii) to identify the major environmental descriptors upon which they depend; and (iii) to identify areas of potential high richness that have been overlooked in available inventories. Most of the predicted species ranges of species covered the majority of southern and central China. Six richness hotspots were predicted, of which four have been described previously, but two overlooked (SE Fujian and SE Qinghai). The prediction model was considered to be relatively accurate and it is recommended that these two new potential hotspots should be subjected to further evaluation and sampling efforts. Amphibians have high ecological preference for high humidity and precipitation, and low annual frost days. ENFA is a useful tool in wildlife conservation assessment because it is able to identify potential hotspots where studies on the correlations between environmental descriptors and the occurrence of particular species could be focused.

  16. TFR2-related hereditary hemochromatosis as a frequent cause of primary iron overload in patients from Central-Southern Italy.

    Science.gov (United States)

    Radio, Francesca Clementina; Majore, Silvia; Binni, Francesco; Valiante, Michele; Ricerca, Bianca Maria; De Bernardo, Carmelilia; Morrone, Aldo; Grammatico, Paola

    2014-01-01

    Hereditary hemochromatosis (HH) is a common Mendelian disorder of iron metabolism. Eighty percent of northern Europeans descendant HH patients carry the same mutation (p.C282Y) in the HFE gene. Simultaneously, due to a founder effect, its frequency varies considerably between different populations. In Central-Southern Italy the prevalence of p.C282Y mutation is low and in several patients the disease has different causes. Four additional rarer forms have been described. Type 3 HH has been reported in about 50 families and no more than 30 TFR2 pathogenic mutations have been globally identified. The aim of this study is to assess the TFR2 role in non-HFE HH pathogenesis. TFR2 sequence analysis was performed on 45 Italian patients without HFE mutations. This study revealed TFR2 biallelic pathogenic mutations in 7/45 (15.6%) individuals. Moreover monoallelic TFR2 deleterious defects (18%) or polymorphisms with unclear meaning (36%) were identified. Besides, we recognized 10 novel variants and 9 described changes. We believe this to be the largest series of type 3 HH patients described so far. Present findings support the hypothesis of a main role of the TFR2 gene in HH pathogenesis in those regions, such as Central-Southern Italy, where the p.C282Y frequency is low. © 2013.

  17. Endangered plant species of the Nevada Test Site, Ash Meadows, and Central-Southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Beatley, J.C.

    1977-02-01

    A total of 15 vascular plant taxa, currently appearing on the Endangered Species list, occur in southern Nye County, Nevada, and/or adjacent Inyo County, California. It is the purpose of this report to record in detail the locations of the plant collections upon which the distributions are based, and other information relevant to their status as Endangered Species, and to recommend the areas to be designated critical habitats.

  18. U-Pb ages and Hf isotope compositions of zircons in plutonic rocks from the central Famatinian arc, Argentina

    Science.gov (United States)

    Otamendi, Juan E.; Ducea, Mihai N.; Cristofolini, Eber A.; Tibaldi, Alina M.; Camilletti, Giuliano C.; Bergantz, George W.

    2017-07-01

    The Famatinian arc formed around the South Iapetus rim during the Ordovician, when oceanic lithosphere subducted beneath the West Gondwana margin. We present combined in situ U-Th-Pb and Lu-Hf isotope analyses for zircon to gain insights into the origin and evolution of Famatinian magmatism. Zircon crystals sampled from four intermediate and silicic plutonic rocks confirm previous observations showing that voluminous magmatism took place during a relatively short pulse between the Early and Middle Ordovician (472-465 Ma). The entire zircon population for the four plutonic rocks yields coherent εHf negative values and spreads over several ranges of initial εHf(t) units (-0.3 to -8.0). The range of εHf units in detrital zircons of Famatinian metasedimentary rocks reflects a prolonged history of the cratonic sources during the Proterozoic to the earliest Phanerozoic. Typical tonalites and granodiorites that contain zircons with evolved Hf isotopic compositions formed upon incorporating (meta)sedimentary materials into calc-alkaline metaluminous magmas. The evolved Hf isotope ratios of zircons in the subduction related plutonic rocks strongly reflect the Hf isotopic character of the metasedimentary contaminant, even though the linked differentiation and growth of the Famatinian arc crust was driven by ascending and evolving mantle magmas. Geochronology and Hf isotope systematics in plutonic zircons allow us understanding the petrogenesis of igneous series and the provenance of magma sources. However, these data could be inadequate for computing model ages and supporting models of crustal evolution.

  19. Fluid-rock interactions during UHP metamorphism: A review of the Dabie-Sulu orogen, east-central China

    Science.gov (United States)

    Zhang, Z. M.; Shen, K.; Liou, J. G.; Dong, X.; Wang, W.; Yu, F.; Liu, F.

    2011-08-01

    Comprehensive review on the characteristics of petrology, oxygen isotope, fluid inclusion and nominally anhydrous minerals (NAMs) for many Dabie-Sulu ultrahigh-pressure (UHP) metamorphic rocks including drill-hole core samples reveals that fluid has played important and multiple roles during complicated fluid-rock interactions attending the subduction and exhumation of supracrustal rocks. We have identified several distinct stages of fluid-rock interactions as follows: (1) The Neoproterozoic supercrustal protoliths of UHP rocks experienced variable degrees of hydration through interactions with cold meteoric water with extremely low oxygen isotope compositions during Neoproterozoic Snow-ball Earth time. (2) A series of dehydration reactions took place during Triassic subduction of the Yangtze plate beneath the Sino-Korean plate; the released fluid entered mainly into volatile-bearing high-pressure (HP) and UHP minerals, such as phengite, zoisite-epidote, talc, lawsonite and magnesite, as well as into UHP NAMs, such as garnet, omphacite and rutile. (3) Silicate-rich supercritical fluid (hydrous melt) existed during the UHP metamorphism at mantle depths >100 km which mobilized many normally fluid-immobile elements and caused unusual element fractionation. (4) The fluid exsolved from the NAMs during the early exhumation of the Dabie-Sulu terrane was the main source for HP hydrate retrogression and generation of HP veins. (5) Local amphibolite-facies retrogression at crustal depths took place by infiltration of aqueous fluid of various salinities possibly derived from an external source. (6) The greenschist-facies overprinting and low-pressure (LP) quartz veins were generated by fluid flow along ductile shear zones and brittle faults during late-stage uplift of the UHP terrane.

  20. 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

  1. Historical Glacier Variations in Southern South America since the Little Ice Age: Examples from Lago Viedma (Southern Patagonia) and Mendoza (Central Andes), Argentina

    Science.gov (United States)

    Nussbaumer, S. U.; Masiokas, M.; Pitte, P.; Berthier, E.; Guerrido, C.; Luckman, B. H.; Villalba, R.

    2013-12-01

    The evaluation of historical information can give valuable insight into past glacier dynamics, especially before the onset of modern measurements. Early photographs and maps depict changes for selected glaciers in southern South America. Within this study, written documents and pictorial historical records (drawings, sketches, engravings, photographs, chronicles, topographic maps) are analysed critically, with a particular focus on two regions: Lago Viedma (El Chaltén, southern Patagonia, 49.5°S, 73.0°W) and the Río Mendoza basin (Mendoza, central Andes, 33.1°S, 69.9°W). For the Lago Viedma area, early historical data for the end of the 19th century stem from the expedition of the Chilean-Argentinean border commission. In addition, the expedition by the German Scientific Society, conducted between 1910 and 1916, and the later photographs by Alberto M. de Agostini give an excellent depiction of the glaciers. Glaciar Viedma is a calving glacier which shows distinct retreat from 1896 until the present (though with a stationary or possibly advancing glacier front between 1930/31 and 1951/52), similar to the neighbouring glaciers. On the contrary, nearby Glaciar Perito Moreno shows an exceptional behaviour: the glacier front has been advancing during the first half of the 20th century, staying in an advanced position until the present. At the beginning of the 20th century, Robert Helbling explored the Argentinean-Chilean Andes together with his friend Friedrich Reichert. In the summer of 1909/10, they started a detailed survey of the highly glacierized Juncal-Tupungato mountains (Río Mendoza basin), leading to the first accurate topographic map of the area published in 1914. Its outstanding quality allows a comparison with contemporary satellite imagery. The area received attention in 1934, when the sudden drainage of a glacier-dammed lake in the upper Río del Plomo valley caused fatalities and considerable damage to constructions and the Transandine Railway. A

  2. First data on the age of rocks from the central part of the Vitoria-Trindade Ridge (Brazil Basin, South Atlantic)

    Science.gov (United States)

    Skolotnev, S. G.; Bylinskaya, M. E.; Golovina, L. A.; Ipat'eva, I. S.

    2011-03-01

    Micropaleontological and isotope-geochronological investigations of calcareous sedimentary rocks and volcanites dredged out from the central portion of the submarine Vitoria-Trindade Ridge during the 24th cruise of R/V Akademik Vavilov have been conducted. It has been established based on micropaleontological analysis, which included determination of the species composition of foraminifera and nannoplankton, that the sequence of sedimentary rocks having a pelagic nature formed on the slopes of the volcanic seamounts in the central portion of the Vitoria-Trindade Ridge from the Early to Mid-Miocene to the Holocene; a good correlation between the degree of lithification of these rocks and their age is observed. It has also been established that the carbonate platforms on the abraded tops of the Davis Seamount and the Dogaressa Bank, which are located in the east-central portion of the Vitoria-Trindade Ridge, started forming in the Early Miocene (19-24 Ma). It has been determined using local U-Pb dating of zircon grains with a SHRIMP-II high resolution secondary ion mass spectrometer that the volcanites forming the upper portion of the volcanic rock sequence of the Jaseur Seamount (29.8 ± 6.6 Ma) located in the west-central portion of the Vitoria-Trindade Ridge date to the Oligocene. The investigations conducted have confirmed the opinion that the Vitoria-Trindade Ridge formed in general because of the activity of the hot spot located under the volcanic Trindade and Martin Vaz Islands. However, separate extended lenticular segments of this ridge existed for a long time as single structures, within which the age of the seamounts was not linearly dependent on the distance from the location of the hot spot. Lenses of hot mantle matter that form at the sublithospheric level as a result of impulses of plume activity and move along with the lithospheric plate play a defining role in the development of individual segments forming the Vitoria-Trindade Ridge.

  3. 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...

  4. 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.

    Chemical properties of the water column were examined at the Indian Deep-sea Environment Experiment (INDEX) site in the Central Indian Basin (CIB), as a part of baseline studies prior to the benthic disturbance experiment for the environmental...

  5. Extensional tectonics, basement uplift and Stephano-Permian collapse basin in a late Variscan metamorphic core complex (Montagne Noire, Southern Massif Central)

    Science.gov (United States)

    Echtler, H.; Malavieille, J.

    1990-05-01

    emplacement in a detachment-controlled basin with a NE-oriented extension direction. Together with regional radiometric data the occurrence of very low-grade metamorphism and intense carbonatization within the basal sediments in the vicinity of the core suggests that the basin was formed during the extensional tectonism related to the uplift of the metamorphic core. The Montagne Noire is a well-defined example of late orogenic extensional tectonics on the southern edge of the Variscan Massif Central. Crustal extension and Stephano-Permian basin formation is related to collapse of the thick, wide Hercynian chain during late Palaeozoic times.

  6. Calibrating water depths of Ordovician communities: lithological and ecological controls on depositional gradients in Upper Ordovician strata of southern Ohio and north-central Kentucky, USA

    Directory of Open Access Journals (Sweden)

    Carlton E. Brett

    2015-02-01

    Full Text Available Limestone and shale facies of the Upper Ordovician Grant Lake Formation (Katian: Cincinnatian, Maysvillian are well exposed in the Cincinnati Arch region of southern Ohio and north-central Kentucky, USA. These rocks record a gradual change in lithofacies and biofacies along a gently northward-sloping ramp. This gradient spans very shallow, olive-gray, platy, laminated dolostones with sparse ostracodes in the south to offshore, nodular, phosphatic, brachiopod-rich limestones and marls in the north. This study uses facies analysis in outcrop to determine paleoenvironmental parameters, particularly those related to water depth (e.g., position of the photic zone and shoreline, relative degree of environmental energy. Within a tightly correlated stratigraphic interval (the Mount Auburn and Straight Creek members of the Grant Lake Formation and the Terrill Member of the Ashlock Formation, we document the occurrence of paleoenvironmental indicators, including desiccation cracks and light-depth indicators, such as red and green algal fossils and oncolites. This permitted recognition of a ramp with an average gradient of 10–20 cm water depth per horizontal kilometer. Thus, shallow subtidal (“lagoonal” deposits in the upramp portion fall within the 1.5–6 m depth range, cross-bedded grainstones representing shoal-type environments fall within the 6–18 m depth range and subtidal, shell-rich deposits in the downramp portion fall within the 20–30 m depth range. These estimates match interpretations of depth independently derived from faunal and sedimentologic evidence that previously suggested a gentle ramp gradient and contribute to ongoing and future high-resolution paleontologic and stratigraphic studies of the Cincinnati Arch region.

  7. Structure of central and southern Mexico from velocity and attenuation tomography

    OpenAIRE

    Chen, Ting; Robert W. Clayton

    2012-01-01

    The 3D V_p, V_p/_Vs, P- and S-wave attenuation structure of the Cocos subduction zone in Mexico is imaged using earthquakes recorded by two temporary seismic arrays and local stations. Direct P wave arrivals on vertical components and direct S wave arrivals on transverse components from local earthquakes are used for velocity imaging. Relative delay times for P and PKP phases from teleseismic events are also used to obtain a deeper velocity structure beneath the southern seismic array. Using ...

  8. Late Cenozoic cooling history of the central Menderes Massif: Timing of the Büyük Menderes detachment and the relative contribution of normal faulting and erosion to rock exhumation

    Science.gov (United States)

    Wölfler, Andreas; Glotzbach, Christoph; Heineke, Caroline; Nilius, Nils-Peter; Hetzel, Ralf; Hampel, Andrea; Akal, Cüneyt; Dunkl, István; Christl, Marcus

    2017-10-01

    Based on new thermochronological data and 10Be-derived erosion rates from the southern part of the central Menderes Massif (Aydın block) in western Turkey, we provide new insights into the tectonic evolution and landscape development of an area that undergoes active continental extension. Fission-track and (U-Th)/He data reveal that the footwall of the Büyük Menderes detachment experienced two episodes of enhanced cooling and exhumation. Assuming an elevated geothermal gradient of 50 °C/km, the first phase occurred with an average rate of 0.90 km/Myr in the middle Miocene and the second one in the latest Miocene and Pliocene with a rate of 0.43 km/Myr. The exhumation rates between these two phases were lower and range from 0.14 to 0.24 km/Myr, depending on the distance to the detachment. Cosmogenic nuclide-based erosion rates for catchments in the Aydın block range from 0.1 to 0.4 km/Myr. The similarity of the erosion rates on both sides of the Aydın block (northern and southern flank) indicate that a rather symmetric erosion pattern has prevailed during the Holocene. If these millennial erosion rates are representative on a million-year timescale they indicate that, apart from normal faulting, erosion in the hanging wall of the Büyük Menderes detachment fault did also contribute to the exhumation of the metamorphic rocks.

  9. Subsurface Determination Of Cavities In Limestone Rock Area By Geoelectric Method In Tinapan Village Todanan Blora District Central Java Indonesia

    Directory of Open Access Journals (Sweden)

    Agus Santoso

    2016-09-01

    Full Text Available Two Dimensional of geoelectric method can be used to find out the conductive formation in the earth surface. The purpose of this research is to give the description about the geological subsurface formation, that the high resistivity value is indicate the potential area of cave and void in the limestone rocks. The dipole dipolegeoelectric method is used in this research with the path of lines is 250 m with 10 m electrode spacing. The total lines is 7 and the azimuth is from east to west. Resistivity method is started with inject the electrical current into the earth by current electrode, then potential difference will arise and measured by potential electrode. Variation value of resistance for each layer rock can calculated by divided potential defference with current value. The existence of the cavity is known by the resistivity value is more than 2500 ohm-m, while the cracks have a resistivity of 1500 to 2500 ohm-m

  10. Peak metamorphic temperatures across the Main Central thrust and through Greater Himalayan rocks in western Bhutan: preliminary insights from Raman spectroscopy of carbonaceous material thermometry

    Science.gov (United States)

    Starnes, J. K.; Long, S. P.; Gordon, S. M.; Soignard, E.

    2016-12-01

    Across the length of the Himalayan orogen, high-grade metamorphic rocks of the Greater Himalaya (GH) overlie lower-grade metasedimentary rocks of the Lesser Himalaya (LH) across the top-to-south Main Central thrust (MCT). The magnitude and structural thickness of inverted metamorphism across the MCT, as well as the peak temperatures obtained by GH rocks at different structural distances above the MCT, remain poorly estimated in much of Bhutan. Here, we utilize Raman spectroscopy of carbonaceous material thermometry to quantify peak temperatures obtained by LH and GH rocks. Nine samples of schist and quartzite were collected along the Puna Tsang Chu valley in western Bhutan, at structural distances ranging between 0.5 km below and 10.6 km above the MCT. The MCT is defined at the first appearance of gneissic banding, which also coincides with the first observed leucosomes and kyanite. Four LH samples were analyzed; samples collected at 530, 320, 300, and 170 m below the MCT yielded temperatures of 498 ± 31 °C, 519 ± 57 °C, 475 ± 37 °C, and 541 ± 36 °C, respectively. Five GH samples, collected 0.05, 3.3, 4.9, 9.0, and 10.6 km above the MCT, yielded temperatures that overlap within error (623 ± 41 °C, 646 ± 38 °C, 600 ± 47 °C, 616 ± 40 °C, and 689 ± 39 °C, respectively). These data illustrate a 125 ± 72 °C increase in peak temperature between 0.5 km below and 0.05 km above the MCT, and approximately static peak temperatures between 0.05-10.6 km above the MCT. These preliminary results bracket MCT inverted metamorphism across a <1 km-thick package of rock, which is thinner than the 5-10 km-thick sections of inverted metamorphism documented across the MCT in much of the central and western Himalaya. In addition, the temperatures above the MCT do not reveal any significant tectonometamorphic discontinuities within the lowest 10.5 km of the GH section. Additional temperature data will be collected to further analyze the trends defined by these

  11. Has Aeshna viridis EVERSMANN, 1836 (Odonata: Aeshnidae really disappeared from southern Poland (East-Central Europe?

    Directory of Open Access Journals (Sweden)

    Buczyński Paweł

    2015-03-01

    Full Text Available 50-100 years ago the southern boundary of the distribution area of Aeshna viridis ran through southern Poland. However, no records of this species from this area have been reported since then. The species is therefore considered as having retreated northwards. The present research disclosed three new sites of A. viridis on the edge of or just beyond its historical distribution area: one in south-western Poland (Trestno: 51°04’N, 17º08’E and two in the south-east of the country (Krasiczyn: 49º46’N, 22º38’E, Bolestraszyce: 49º49’N, 22º51’E. All the sites were anthropogenic. This demonstrates the survival of a number of populations and the formation of new ones in water bodies formed de novo or to which Stratiotes aloides was introduced artificially. This suggests that the conservation of A. viridis is possible in this region.

  12. Geophysical demonstration of the absence of correlation between lineaments and hydrogeologically usefull fractures: Case study of the Sanon hard rock aquifer (central northern Burkina Faso)

    Science.gov (United States)

    Soro, Donissongou Dimitri; Koïta, Mahamadou; Biaou, Chabi Angelbert; Outoumbe, Eli; Vouillamoz, Jean-Michel; Yacouba, Hamma; Guérin, Roger

    2017-05-01

    The conceptualization of hard rock aquifers in terms of their geometry and structure has undergone considerable progress over the last two decades. Despite these advances, hydrogeologists are still divided by the models used to describe two central concepts: (i) the influence of weathering processes on hydraulic conductivity; (ii) the influence of tectonics on the hydraulic conductivity of hard rock aquifers. In order to provide further insight into this debate, the present study proposes a conceptual model for hard rock aquifers, based on an integrated hydrogeological and geophysical approach, using information acquired at different scales. The data and observations used for this case study were derived from the Sanon experimental site, located in Burkina Faso, which is presently exposed to a Sudano-Sahelian climate. The methodological approach consisted firstly in developing a description of the site's weathering profile at the scale of a borehole, based on lithologs and electrical resistivity logs. In a second step, the site's ridge to ridge (longitudinal) weathering profile was established from several 2D resistivity sections crossing a maximum number of lineament structures, which in some prior studies were considered to be the superficial manifestation of tectonic fractures. The results show that at that scale the weathering profile is comprised of three main layers, which from top to bottom are referred to as: the saprolite, the fissured layer and the fresh rock. This weathering profile model is consistent with other models proposed in recent years, suggesting that the hydraulic conductivity of hard rock aquifers is a consequence of weathering processes, rather than tectonic fracturing. Tectonic fractures are not visible on the 2D sections of the ridge to ridge profiles, and the lineaments originally thought to be overground representations of tectonic fractures are likely to have different origins. The lack of a substantial correlation between tectonic

  13. Structural observations and U-Pb mineral ages from igneous rocks at the Archaean-Palaeoproterozoic boundary in the Salahmi Schist Belt, central Finland: constraints on tectonic evolution

    Directory of Open Access Journals (Sweden)

    Pietikäinen, K.

    1999-06-01

    Full Text Available The study area in Vieremä, central Finland, contains part of Archaean-Palaeoproterozoic boundary. In the east, the area comprises Archaean gneiss and the Salahmi Schist Belt. The rocks of the schist belt are turbiditic metagreywackes, with well-preserved depositional structures, occurring as Proterozoic wedge-shaped blocks, and staurolite schists, the latter representing higher-strained and metamorphosed equivalents of the metagreywackes. In the west of the area there is an Archaean gneiss block, containing strongly elongated structures, and deformed Svecofennian supracrustal rocks, which are cut by deformed granitoids. These are juxtaposed with the schist belt. The boundaries of these tectonometamorphic blocks are narrow, highly strained mylonites and thrust zones. The metamorphic grade of the supracrustal rocks increases from east to west, the increase being stepwise across the mylonitic block boundaries. The rocks are more deformed from east to west with younger structures overprinting. In the staurolite schists of the Salahmi Schist Belt, the most prominent structure is a lineation (L2 that overprints the bedding and axial plane foliation. In Sorronmäki quarry, at the western boundary of the schist belt, this Palaeoproterozoic lineation dominates all the structures in tonalite gneiss, which gives a U-Pb age of 2731±6 Ma. Southeast of the quarry, at the same boundary, the Salahmi schists have been overturned towards the northeast, suggesting that the Archaean gneiss at Sorronmäki has been thrust towards the northeast over these rocks. In the western part of the study area, the Leppikangas granodiorite that intrudes the Svecofennian supracrustal rocks gives a U-Pb age of 1891+6 Ma. In the granodiorite, a strong lineation formed by the intersection of two foliations, which maybe L2 is associated with thrusting towards the northeast. The monazite age of the Archaean Sorronmäki gneiss is 1817+3 Ma, and the titanite age of the Svecofennian

  14. Trace-element geochemistry of metabasaltic rocks from the Yukon-Tanana Upland and implications for the origin of tectonic assemblages in east-central Alaska

    Science.gov (United States)

    Dusel-Bacon, C.; Cooper, K.M.

    1999-01-01

    We present major- and trace- element geochemical data for 27 amphibolites and six greenstones from three structural packages in the Yukon-Tanana Upland of east-central Alaska: the Lake George assemblage (LG) of Devono-Mississippian augen gneiss, quartz-mica schist, quartzite, and amphibolite; the Taylor Mountain assemblage (TM) of mafic schist and gneiss, marble, quartzite, and metachert; and the Seventymile terrane of greenstone, serpentinized peridotite, and Mississippian to Late Triassic metasedimentary rocks. Most LG amphibolites have relatively high Nb, TiO2, Zr, and light rare earth element contents, indicative of an alkalic to tholeiitic, within-plate basalt origin. The within-plate affinities of the LG amphibolites suggest that their basaltic parent magmas developed in an extensional setting and support a correlation of these metamorphosed continental-margin rocks with less metamorphosed counterparts across the Tintina fault in the Selwyn Basin of the Canadian Cordillera. TM amphibolites have a tholeiitic or calc-alkalic composition, low normalized abundances of Nb and Ta relative to Th and La, and Ti/V values of ocean-floor basalt origin. Y-La-Nb proportions in both TM and Seventymile metabasalts indicate the proximity of the arc and marginal basin to continental crust. The arc geochemistry of TM amphibolites is consistent with a model in which the TM assemblage includes arc rocks generated above a west-dipping subduction zone outboard of the North American continental margin in mid-Paleozoic through Triassic time. The ocean-floor or within-plate basalt geochemistry of the Seventymile greenstones supports the correlation of the Seventymile terrane with the Slide Mountain terrane in Canada and the hypothesis that these oceanic rocks originated in a basin between the continental margin and an arc to the west.

  15. Major and trace-element composition and pressure-temperature evolution of rock-buffered fluids in low-grade accretionary-wedge metasediments, Central Alps

    Science.gov (United States)

    Miron, George D.; Wagner, Thomas; Wälle, Markus; Heinrich, Christoph A.

    2013-05-01

    The chemical composition of fluid inclusions in quartz crystals from Alpine fissure veins was determined by combination of microthermometry, Raman spectroscopy, and LA-ICPMS analysis. The veins are hosted in carbonate-bearing, organic-rich, low-grade metamorphic metapelites of the Bündnerschiefer of the eastern Central Alps (Switzerland). This strongly deformed tectonic unit is interpreted as a partly subducted accretionary wedge, on the basis of widespread carpholite assemblages that were later overprinted by lower greenschist facies metamorphism. Veins and their host rocks from two locations were studied to compare several indicators for the conditions during metamorphism, including illite crystallinity, graphite thermometry, stability of mineral assemblages, chlorite thermometry, fluid inclusion solute thermometry, and fluid inclusion isochores. Fluid inclusions are aqueous two-phase with 3.7-4.0 wt% equivalent NaCl at Thusis and 1.6-1.7 wt% at Schiers. Reproducible concentrations of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, B, Al, Mn, Cu, Zn, Pb, As, Sb, Cl, Br, and S could be determined for 97 fluid inclusion assemblages. Fluid and mineral geothermometry consistently indicate temperatures of 320 ± 20 °C for the host rocks at Thusis and of 250 ± 30 °C at Schiers. Combining fluid inclusion isochores with independent geothermometers results in pressure estimates of 2.8-3.8 kbar for Thusis, and of 3.3-3.4 kbar for Schiers. Pressure-temperature estimates are confirmed by pseudosection modeling. Fluid compositions and petrological modeling consistently demonstrate that chemical fluid-rock equilibrium was attained during vein formation, indicating that the fluids originated locally by metamorphic dehydration during near-isothermal decompression in a rock-buffered system.

  16. Palaeomagnetism of Archaean rocks of the Onverwacht Group, Barberton Greenstone Belt (southern Africa): Evidence for a stable and potentially reversing geomagnetic field at ca. 3.5 Ga

    Science.gov (United States)

    Biggin, Andrew J.; de Wit, Maarten J.; Langereis, Cor G.; Zegers, Tanja E.; Voûte, Sara; Dekkers, Mark J.; Drost, Kerstin

    2011-02-01

    Palaeomagnetic data from the Palaeoarchaean Era (3.2-3.6 Ga) have the potential to provide us with a great deal of information about early conditions within, and processes affecting, the Earth's core, mantle, and surface environment. Here we present new data obtained from some of the oldest palaeomagnetic recorders in the world: igneous and sedimentary rocks from the Onverwacht Group of the Barberton Greenstone Belt (Kaapvaal Craton, southern Africa). Our palaeomagnetic measurements strengthen a recently published positive conglomerate test (Y. Usui, J.A. Tarduno, M. Watkeys, A. Hofmann and R.D. Cottrell, 2009) and our new U-Pb date constrains the conglomerate to older than 3455 ± 8 Ma. The new palaeomagnetic data from other units are nontrivial to interpret and are of uncertain reliability when taken individually; similar, we argue, to all other published palaeomagnetic data of this age. Nonetheless, four poles (two new, two derived from published data) produced from high temperature components of magnetisation recorded in the Komati, Noisy, and Hooggenoeg formations exhibit considerably improved clustering when their directions are corrected for differences in attitude resulting from a large fold structure dated at 3.23 Ga. On the basis of this enhanced consistency in stratigraphic coordinates, the positive conglomerate test, and the absence of any clear indications of their remagnetisation from comparison with younger poles, we argue that these are the most trustworthy palaeomagnetic results yet produced from any rocks of Palaeoarchaean age. When taken in conjunction with published data, the new results present the most compelling evidence to date that the Earth had a stable geomagnetic field at ca. 3.5 Ga in addition to presenting tentative evidence that it was undergoing polarity reversals. The data do not appear to support a claim, made previously from Palaeoarchean palaeomagnetic data from the Pilbara Craton (Y. Suganuma, Y. Hamano, S. Niitsuma, M. Hoashi

  17. Isotopic constraints on the genesis of base-metal ores in southern and central Sardinia

    Science.gov (United States)

    Ludwig, K. R.; Vollmer, R.; Turi, B.; Simmons, K.R.; Perna, G.

    1989-01-01

    The Pb-Zn-Ag deposits of southwestern and central Sardinia occur within a restricted region, but comprise a variety of mineralization ages and styles. New Pb-isotope data, together with published data provide a reasonably coherent picture of possible sources for the various types of deposits. -from Authors

  18. 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

  19. Aeromagnetic anomalies reveal hidden tectonic and volcanic structures in the central sector of the Aeolian Islands, southern Tyrrhenian Sea, Italy

    Science.gov (United States)

    de Ritis, Riccardo; Ventura, Guido; Chiappini, Massimo

    2007-10-01

    Salina Island (Italy) in the central Aeolian chain is the northernmost volcanic structure of an elongated ridge on a regional shear zone with NNW-SSE strike-slip faults and second-order N-S and NE-SW faults. Modeling of high-resolution, low-altitude aeromagnetic data collected in 2003 and 2005 using volcanological data constraints reveals the inner structure of the Salina volcanoes and surrounding marine regions. Regional negative anomalies overlie E-W elongated sedimentary basins related to the early Pliocene-Pleistocene opening of the southern Tyrrhenian Sea. These negative anomalies flank positively magnetized crust of Salina and seamounts off its eastern coast where the shorter-wavelength anomalies map late Pleistocene-Holocene volcanic conduits, dikes, and faults. The magnetic and volcanological data indicate that the early (circa 168-100 ka) basaltic to andesitic Salina volcanism developed along N-S and NE-SW tectonic faults, whereas the more recent andesitic lavas and rhyolitic pyroclastics (circa 100-13 ka) were emitted by vents related to the main NW-SE faults. The tectonic structures also controlled the location of the seamounts around the island and the geometry of the volcano-tectonic collapses. Salina volcanism was emplaced on a NNW-SSE tear fault of the presently developing roll-back slab in the southern Tyrrhenian Sea.

  20. Application of Phase-Weighted Stacking to Low-Frequency Earthquakes near the Alpine Fault, Central Southern Alps, New Zealand

    Science.gov (United States)

    Baratin, L. M.; Townend, J.; Chamberlain, C. J.; Savage, M. K.

    2015-12-01

    Characterising seismicity in the vicinity of the Alpine Fault, a major transform boundary late in its typical earthquake cycle, may provide constraints on the state of stress preceding a large earthquake. Here, we use recently detected tremor and low-frequency earthquakes (LFEs) to examine how slow tectonic deformation is loading the Alpine Fault toward an anticipated major rupture. We work with a continuous seismic dataset collected between 2009 and 2012 from a network of short-period seismometers, the Southern Alps Microearthquake Borehole Array (SAMBA). Fourteen primary LFE templates have been used to scan the dataset using a matched-filter technique based on an iterative cross-correlation routine. This method allows the detection of similar signals and establishes LFE families with common hypocenter locations. The detections are then combined for each LFE family using phase-weighted stacking (Thurber et al., 2014) to produce a signal with the highest possible signal to noise ratio. We find this method to be successful in increasing the number of LFE detections by roughly 10% in comparison with linear stacking. Our next step is to manually pick polarities on first arrivals of the phase-weighted stacked signals and compute preliminary locations. We are working to estimate LFE focal mechanism parameters and refine the focal mechanism solutions using an amplitude ratio technique applied to the linear stacks. LFE focal mechanisms should provide new insight into the geometry and rheology of the Alpine Fault and the stress field prevailing in the central Southern Alps.

  1. Fire Regime in Marginal Jack Pine Populations at Their Southern Limit of Distribution, Riding Mountain National Park, Central Canada

    Directory of Open Access Journals (Sweden)

    Jacques C. Tardif

    2016-09-01

    Full Text Available In central Canada, long fire history reconstructions are rare. In a context where both anthropogenic and climate influences on fire regime have changed, Parks Canada has a mandate to maintain ecological integrity. Here we present a fire history derived from fire-scarred jack pine (Pinus banksiana Lamb. trees growing at their southern distribution limit in Riding Mountain National Park (RMNP. In Lake Katherine Fire Management Unit (LKFMU, a subregion within the park, fire history was reconstructed from archival records, tree-ring records, and charcoal in lake sediment. From about 1450 to 1850 common era (CE the fire return intervals varied from 37 to 125 years, according to models. During the period 1864–1930 the study area burned frequently (Weibull Mean Fire Intervals between 2.66 and 5.62 years; this period coincided with the end of First Nations occupation and the start of European settlement. Major recruitment pulses were associated with the stand-replacing 1864 and 1894 fires. This period nevertheless corresponded to a reduction in charcoal accumulation. The current fire-free period in LKFMU (1930–today coincides with RMNP establishment, exclusion of First Nations land use and increased fire suppression. Charcoal accumulation further decreased during this period. In the absence of fire, jack pine exclusion in LKFMU is foreseeable and the use of prescribed burning is advocated to conserve this protected jack pine ecosystem, at the southern margins of its range, and in the face of potential climate change.

  2. Crust and upper-mantle seismic anisotropy variations from the coast to inland in central and Southern Mexico

    Science.gov (United States)

    Castellanos, Jorge; Pérez-Campos, Xyoli; Valenzuela, Raúl; Husker, Allen; Ferrari, Luca

    2017-07-01

    Subduction zones are among the most dynamic tectonic environments on Earth. Deformation mechanisms of various scales produce networks of oriented structures and faulting systems that result in a highly anisotropic medium for seismic wave propagation. In this study, we combine shear wave splitting inferred from receiver functions and the results from a previous SKS-wave study to quantify and constrain the vertically averaged shear wave splitting at different depths along the 100-station MesoAmerican Subduction Experiment array. This produces a transect that runs perpendicular to the trench across the flat slab portion of the subduction zone below central and southern Mexico. Strong anisotropy in the continental crust is found below the Trans-Mexican Volcanic Belt (TMVB) and above the source region of slow-slip events. We interpret this as the result of fluid/melt ascent. The upper oceanic crust and the overlying low-velocity zone exhibit highly complex anisotropy, while the oceanic lower crust is relatively homogeneous. Regions of strong oceanic crust anisotropy correlate with previously found low Vp/Vs regions, indicating that the relatively high Vs is an anisotropic effect. Upper-mantle anisotropy in the southern part of the array is in trench-perpendicular direction, consistent with the alignment of type-A olivine and with entrained subslab flow. The fast polarization direction of mantle anisotropy changes to N-S in the north, likely reflecting mantle wedge corner flow perpendicular to the TMVB.

  3. 'All under one roof?' differences in food availability and shopping patterns in Southern France and Central England.

    Science.gov (United States)

    Pettinger, Clare; Holdsworth, Michelle; Gerber, Mariette

    2008-04-01

    This study investigates patterns of food shopping and availability of fruit and vegetables and snack foods in a northern European (Central England) and southern European region (Southern France). Two studies were conducted in England (Nottingham) and France (Montpellier): (i) Cross-sectional population surveys using self-administered postal questionnaires to assess type of outlets used for food shopping in random population samples (England: n = 826; Montpellier: n = 766). (ii) Food availability studies to determine: the number of food outlets in defined comparable geographical areas; the number stocking fruit and vegetables, their quality and energy dense snacks. The English respondents used supermarkets most regularly (P difference was not significant. Crisps (P England. Food shopping was done 'under one roof' more often in England, whereas in France, shopping was done in smaller specialist shops, which was reflected in their presence within the locality. Even though availability of fruit and vegetables was good in both countries, snack foods were more abundant in England. This clearly impacts on the food environment and could explain the higher prevalence of obesity in England, factors which are also influenced by culture, habits and convenience.

  4. Some features of the quantitative distribution of sipunculan worms (Sipuncula in the central and southern Barents Sea

    Directory of Open Access Journals (Sweden)

    Evgeny A. Garbul

    2012-02-01

    Full Text Available The article reports on the current state of the sipunculan fauna of the central and southern parts of the Barents Sea. The main quantitative parameters (biomass and abundance of the sipunculan populations are obtained, and the contribution of sipunculids to the total benthos biomass is assessed. The major factors causing long-term variations in Sipunculidae distribution and abundance are evaluated for the area in question.      The investigations show that the most commonly encountered sipunculan species are Nephasoma diaphanes diaphanes,N. abyssorum abyssorum and Phascolion strombus strombus. The main contribution to the total benthos biomass comes from the two species most typical of the Barents Sea benthic fauna: Golfingia margaritacea margaritacea and G. vulgaris vulgaris. It is possible that the reductionin Golfingia biomass between the 1970s and 1990s, described in the article, is due to changes in the sampling methodology.

  5. Four Species of Oribatid Mites (Acari: Oribatida from Central and Southern Mongolia, with Notes on the Genera Montizetes and Zachvatkinibates

    Directory of Open Access Journals (Sweden)

    Badamdorj Bayartogtokh

    2003-06-01

    Full Text Available In the present work four species of oribatid mites from central and southern parts of Mongolia are studied, and two of them, namely Zachvatkinibates mongolicus sp. nov. and Montizetes serratus sp. nov. are described as new to science. Two other species, Kunstella foveolata Krivolutsky and Liebstadia pannonica(Wil1mann are recorded as new to the fauna of Mongolia, and the latter species is reported for the first time from Asia. Description of new and redescription of known species, and data on geographic distribution of known species are given. Anew combination, Montizetes tianshanensis (Wen comb. nov. is proposed. Identification keys to the world species of the genera Zachvatkinibates and Montizetes are provided.

  6. Anthropogenic contaminants in Indo-Pacific humpback and Australian snubfin dolphins from the central and southern Great Barrier Reef.

    Science.gov (United States)

    Cagnazzi, Daniele; Fossi, Maria Cristina; Parra, Guido J; Harrison, Peter L; Maltese, Silvia; Coppola, Daniele; Soccodato, Alice; Bent, Michael; Marsili, Letizia

    2013-11-01

    We present the first evidence of accumulation of organochlorine compounds (DDTs, PCBs, HCB) and polycyclic aromatic hydrocarbons (PAHs) in Indo-Pacific humpback and Australian snubfin dolphins from the central and southern Great Barrier Reef. These dolphins are considered by the Great Barrier Marine Park Authority to be high priority species for management. Analyses of biopsy samples, collected from free ranging individuals, showed PAHs levels comparable to those reported from highly industrialized countries. DDTs and HCB were found at low levels, while in some individuals, PCBs were above thresholds over which immunosuppression and reproductive anomalies occur. These results highlight the need for ongoing monitoring of these and other contaminants, and their potential adverse effects on dolphins and other marine fauna. This is particularly important given the current strategic assessment of the Great Barrier Reef World Heritage Area being undertaken by the Australian Government and the Queensland Government. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Soil physical and chemical properties associated with flat rock and riparian forest communities

    Science.gov (United States)

    David O. Mitchem; James E. Johnson; Laura S. Gellerstedt

    2006-01-01

    Flat Rock forest communities are unique ecosystems found adjacent to some large rivers in the Central and Southern Appalachian Mountains. Characterized by thin, alluvial soils overlying flat, resistant sandstone, these areas are maintained by severe flooding and have unique associated plant systems. With the advent of dams to control flooding in the 20th century, many...

  8. New taxa, combinations and records of Pteridophyta from southern and central Africa

    Directory of Open Access Journals (Sweden)

    J. E. Burrows

    1989-12-01

    Full Text Available Four new taxa of ferns are described and illustrated from southern Africa:  Ophioglossum convexum J.E. Burrows, Mohria caffrorum (L. Desv. var. ferruginea J.E. & S.M. Burrows,  Marsilea farinosa Launert subsp. arrecta J.E. Burrows and Asplenium sebungweense J.E. Burrows. The combination of Grammitis rigescens (Bory ex Willd. J.E. Burrows is made. Ophioglossum thomasii Clausen,  O. rube Hum Welw. ex A. Braun.  Vinana ensiformis Swartz and Asplenium buettneri Hieron. ex Brause are new records for Zimbabwe, while Hymenophyllum splendidum V.d. Bosch and  Asplenium uhligii Hieron. are new records for Malawi and Zimbabwe. Actiniopteris semiflabellata Pichi-Sermolli is recorded from Namibia and Thelypteris oppositiformis (C. Chr. Ching is recorded from the Transvaal.

  9. A review of existing trauma and musculoskeletal impairment (TMSI) care capacity in East, Central, and Southern Africa.

    Science.gov (United States)

    Chokotho, Linda; Jacobsen, Kathryn H; Burgess, David; Labib, Mohamed; Le, Grace; Peter, Noel; Lavy, Christopher B D; Pandit, Hemant

    2016-09-01

    We conducted an assessment of orthopaedic surgical capacity in the following countries in East, Central, and Southern Africa: Burundi, Ethiopia, Kenya, Malawi, Mozambique, Rwanda, Tanzania, Uganda, Zambia, and Zimbabwe. We adapted the WHO Tool for Situational Analysis to Assess Emergency and Essential Surgical Care with questions specific to trauma and orthopaedic care. In May 2013-May 2014, surgeons from the College of Surgeons of East, Central and Southern Africa (COSECSA) based at district (secondary) and referral (tertiary) hospitals in the region completed a web-based survey. COSECSA members contacted other eligible hospitals in their country to collect further data. Data were collected from 267 out of 992 (27%) hospitals, including 185 district hospitals and 82 referral hospitals. Formal accident and emergency departments were present in 31% of hospitals. Most hospitals had no general or orthopaedic surgeons or medically-qualified anaesthetists on staff. Functioning mobile C-arm X-ray machines were available in only 4% of district and 27% of referral hospitals; CT scanning was available in only 3% and 26%, respectively. Closed fracture treatment was offered in 72% of the hospitals. While 20% of district and 49% of referral hospitals reported adequate instruments for the surgical treatment of fractures, only 4% and 10%, respectively, had a sustainable supply of fracture implants. Elective orthopaedic surgery was offered in 29% and Ponseti treatment of clubfoot was available at 42% of the hospitals. The current capacity of hospitals in sub-Saharan Africa to manage traumatic injuries and orthopaedic conditions is significantly limited. In light of the growing burden of trauma and musculoskeletal impairment within this region, concerted efforts should be made to improve hospital capacity with equipment, trained personnel, and specialist clinical services. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Changes in fish diversity and community structure in the central and southern Yellow Sea from 2003 to 2015

    Science.gov (United States)

    Chen, Yunlong; Shan, Xiujuan; Jin, Xianshi; Johannessen, Arne; Yang, Tao; Dai, Fangqun

    2017-07-01

    The central and southern Yellow Sea is an important overwintering ground for many fish species in the Bohai Sea and Yellow Sea. For better understanding the status of the fish community after years of heavy exploitation, variations in fish community structure and diversity were analyzed using data from bottom trawls during 2003-2015. Five fish assemblage indices all showed fluctuations without clear trends from 2003 to 2015, yet there were strong positive and significant correlations (P fish catch. Multivariate analysis showed that two year groups could be pooled for the fish community: Group I consisted of the years 2006, 2007, 2008 and 2015, while Group II consisted of the years 2003, 2004, 2005, 2009, 2010 and 2014; the groups aggregated with 63.71% similarity, indicating a high level of similarity among all years. The multivariate dispersion values were 1.455 and 0.818 for Groups I and II, respectively, indicating greater variances in fish assemblage structure in Group I than that in Group II. Similarity of percentage analysis demonstrated that the average similarities for Group I and Group II were 71.58% and 67.51%, respectively. Size-spectra analysis revealed no consistent trend in the intercept and slope (P > 0.05); there were also no significant differences between the slope of the size-spectra and fishing effort. The catch per unit effort and mean individual weight analyses of the whole fish assemblage both showed a significantly decreasing trend over time. Overall, the results showed that the fish community structure in the central and southern Yellow Sea was relatively stable from 2003 to 2015 and the study could be used as a reference for supporting ecosystem-based fishery management.

  11. Platinum group elements geochemistry of ultramafic and associated rocks from Pindar in Madawara Igneous Complex, Bundelkhand massif, central India

    Science.gov (United States)

    Balaram, V.; Singh, S. P.; Satyanarayanan, M.; Anjaiah, K. V.

    2013-02-01

    Ultramafic rocks comprising dunite, harzburgite, lherzolite, olivine webserite and websterite occur as intrusives in the form of small hillocks at Pindar into the granite-gneisses of Bundelkhand Gneissic Complex (BnGC). The peridotites are dominated by olivine cumulates where chromite and precious metal-bearing sulphides crystallized along with pyroxenes, subsequent to crystallization of olivine into the interstitial spaces of cumulates during cooling. Ultramafic rocks of Pindar are characterized by high MgO (up to 46.0 wt%) and FeO (up to 5.8 wt%); low SiO2 (40.8 to 48.0 wt%), TiO2 (0.2 to 0.5 wt%), Al2O3 (~3.2 wt% av.), CaO (~2.7 wt% av.) and Cu (11 to 73 μg/g). Cr and Ni values range from 2297 to 3150 μg/g and 2434 to 2767 μg/g, respectively. Distribution of Ir (up to 20 ng/g), Ru (27 to 90 ng/g), Rh (3 to 14 ng/g), Pt (18 to 72 ng/g), Pd (10 to 27 ng/g) and Au (22 to 57 ng/g) indicate platinum group element (PGE) and associated gold mineralization in these ultramafic rocks. A mineral phase representing sperrylite (PtAs2) was also identified within the sulphides in scanning electron microscopy with energy dispersive spectrometer (SEM-EDS) studies. The primitive mantle-normalized siderophile elements pattern shows platinum group element PGE (PPGE) enrichment (Rh, Pt, Pd). Discrimination diagrams of Pd/Ir vs. Ni/Cu, Pd/Pt vs. Ni/Cu, Cu/Pd vs. Pd, and Cu vs. Pd for the peridotites of Pindar attribute to affinity towards komatiite magma, derived from high degree of partial melting of prolonged depleted mantle, and the sulphur saturation condition incurred during the crystallization of chromite which was favourable for PGE mineralization.

  12. Zircon U-Pb geochronology and emplacement history of intrusive rocks in the Ardestan section, central Iran

    Energy Technology Data Exchange (ETDEWEB)

    Sarjoughian, F.; Kananian, A.

    2017-11-01

    The Urumieh-Dokhtar Magmatic Arc (UDMA) is part of the Alpine–Himalayan orogenic belt and interpreted to be a subduction-related Andean-type magmatic arc. Along this belt, Eocene volcanics and some gabbroic to granitic bodies crop out. The main rock types of the studied intrusion are granite, granodiorite, and diorite. They have geochemical features typical of magnesian, calc-alkaline, metaluminous to slightly peraluminous granites and I-type intrusive rock that have a strong enrichment in Large-Ion Lithophile (LIL) elements (e.g. Rb, Ba, Sr), and a depletion in High Field Strength (HFS) elements (e.g. Nb, Ti, P), typical of subduction-related magmas. Zircon U-Pb dating was applied to determine the emplacement ages of the different intrusions in the Ardestan area. Among them the Kuh-e Dom diorite is 53.9±0.4Ma old; the Kuh-e Dom granodiorite is 51.10±0.4Ma old; the Mehrabad granodiorite is 36.8±0.5Ma old, the Nasrand granodiorite is 36.5±0.5Ma old, the Zafarghand granodiorite is 24.6±1.0Ma old, and the Feshark granodiorite is 20.5±0.8Ma old. These results delineate more accurately the magmatic evolution related to the Neotethyan subduction from the Lower Eocene to Lower Miocene, and the subsequent Zagros orogeny that resulted from the Arabia-Eurasia collision. The emplacement of these intrusive rocks inside the UDMA, which has a close relationship with the collisional orogeny, is transitional from a subduction-related setting to post-collisional setting in the Ardestan area.

  13. The Magnetic Properties and Fabric of Granulite Facies Deep Crustal Rocks in the Mount Hay Region, southeastern Arunta Block, Central Australia

    Science.gov (United States)

    Kelso, P. R.; Barry, A. J.; Carley, S.; Jackson, M.; Tikoff, B.; Goodwin, L.

    2007-12-01

    The granulite-facies deformation in the Mount Hay region of the Arunta Inlier in central Australia occurred at 816±27°C and approximately 800 MPa. Mount Hay is comprised primarily of mafic granulite plus lesser amounts of charnockitic, porphyroclastic, and quartzofeldspathic granulite. Magnetic fabric of these variably deformed, deep crustal rocks provide insights into the deformation processes occurring within high grade metamorphic shear zones. Samples were collected along a north-south trending 5.5 km traverse. Magnetic measurements include anisotropy of magnetic susceptibility (AMS), high and low temperature susceptibility measurements, saturation remnant magnetization as a function of low temperature, and hysteresis loops. AMS studies in the Mount Hay region show S>L to S>>L (stronger foliation than lineation) for mafic and porphyroclastic granulites, while Srock types are pseudo-single-domain to multidomain. The mafic granulites generally have the lowest coercivity of remanence to coercivity ratio, indicating a finer magnetic grain size, typically pseudo-single- domain. Low-temperature saturation isothermal remanent magnetization yielded Verwey transition temperatures ranging from 111-123 K, suggesting the magnetite is in some cases slightly oxidized or contains impurities. A weak correlation between lower Verwey transitions and lower coercivity of remanence to coercivity ratio is consistent with oxidation due to a larger surface area to volume ratio for finer grain magnetite grains. The dominant Curie temperatures are approximately 567°C, typical of magnetite with minor cation substitution. Most samples exhibit a secondary ordering transition of ~330°C and a 35 K low-temperature saturation isothermal remanence transition during warming which are both characteristic of pyrrhotite. AMS ellipsoid principle directions correlate well

  14. Fishery of the short-necked clam Paphia undulata in Southern Negros Occidental, Central Philippines

    Directory of Open Access Journals (Sweden)

    Karen A. Villarta

    2010-06-01

    Full Text Available This study documents the fishery of the short-necked clam Paphia undulata in coastal waters of southern Negros Occidental. Catch and effort estimates were determined based on daily records of compressor divers gathered between February-July 2008 in Himamaylan City and July 2008-May 2009 in the town of Hinigaran. Fishing and marketing practices in both areas were also documented and population biology information noted.Compared to earlier conditions, present fishing patterns show a worsened stage of overexploitation primarily characterized by collection of predominantly small and immature (mostly <45 mm shell lengths sizes. Intensity/duration and location of fishing also varied due to both abundance and demand factors.The difference in sizes of clams and the varying fishing durations in each area suggest a non-uniform pattern of settlement resulting most likely from differential larval recruitment, the likely factors causing the local boom and bust fishery. The larger and long term extent of the effect of these factors can only be further investigated by parallel 2-3 year fishery-dependent and -independent surveys

  15. Delivering kidney cancer care in rural Central and Southern Illinois: a telemedicine approach.

    Science.gov (United States)

    Alanee, S; Dynda, D; LeVault, K; Mueller, G; Sadowski, D; Wilber, A; Jenkins, W D; Dynda, M

    2014-11-01

    There is a growing body of experience and research suggesting that telemedicine (video conferencing, smart phones and online patient portals) could be the solution to addressing gaps in the provision of specialised healthcare in rural areas. The proposed role of telemedicine in providing needed services in hard to reach areas is not new. The United States Telecommunication Act of 1996 provided the initial traction for telemedicine by removing important economic and legal obstacles regarding the use of technology in healthcare delivery. This initial ruling has been supplemented by the availability of federal funding to support efforts aimed at developing telemedicine in underserved areas. In this paper, we explore one aspect of disease disparity pertinent to rural Illinois (kidney cancer incidence and mortality) and describe how we are planning to use an existing telemedicine program at Southern Illinois University School of Medicine (SIUSOM) to improve kidney cancer (Kca) care in rural Illinois. This represents an example of the possible role of telemedicine in addressing healthcare disparities in rural areas/communities and provides a description of general challenges and barriers to the implementation and maintenance of such systems. © 2014 John Wiley & Sons Ltd.

  16. Preliminary report on seismic-reflection studies of crustal structure in the western, central, and southern United States

    Science.gov (United States)

    Roller, J.C.; Strozier, O.P.; Jackson, W.H.; Healy, J.H.

    1963-01-01

    During 1963 the U.S. Geological Survey, with the assistance of United ElectroDynamics, Inc., recorded five separate reversed seismic profiles. In addition to these profiles, the U.S. Geological Survey participated in a seismic-calibration program for the DRIBBLE experiment at Tatum Dome, Mississippi, a 20,000-pound shot near Dexter, Missouri, and in a cooperative seismic experiment in the Lake Superior region. This work is a continuation of the program started in 1961; however, the emphasis has shifted from a detailed study of the earth's crust in the western United States to a study of crustal structure in various geologic environments including the Wyoming thrust belt, Colorado Plateau, Central Lowlands, the Gulf Coastal Plain, and the southern part of the Canadian Shield. The U.S. Geological Survey has now completed reversed seismic-refraction profiles in nine different geologic provinces. These data present a promising indication that it may be possible to predict the crustal structure in unexplored areas by considering the regional geologic and physiographic environment. The following Pn velocities have been determined: 8.2 km/sec in the Wyoming thrust belt, 7.9 km/sec in the Colorado Plateau, 8.1 km/sec in the Central Lowlands, and about 8.2 km/sec in the Gulf Coastal Plain. The data from the Lake Superior region have not yet been interpreted.

  17. Geochemical evolution of groundwater in carbonate aquifers of southern Latium region, central Italy

    Directory of Open Access Journals (Sweden)

    Giuseppe Sappa

    2013-03-01

    Full Text Available Spring and well water samples, from carbonate aquifers of Latium region, have been characterized to determine the hydrochemical processes governing the evolution of the groundwater. Most of the spring samples, issuing from Lepini, Ausoni and Aurunci Mts., are characterized as alkaline earth HCO3 waters, however, some samples show a composition of Cl--SO4 -- alkaline earth waters. Groundwater samples from Pontina Plain shows three different hydrochemical facies: alkaline earth HCO3 type, Cl-- SO4 -- alkaline earth type and Cl--SO4 -- alkaline type waters. Geochemical modeling and saturation index computation of the sampled waters show an interaction with calcareous and calcareous-dolomitic lithologies. Most of the springs and wells was kinetically saturated with respect to calcite and dolomite, and all the samples were below the equilibrium state with gypsum. This indicates that the groundwater has capacity to dissolve the gypsum along the flow paths. The electrical conductivity and Cl- concentrations of the sampled waters show a positive trend with the decrease in the distance from the coast, highlighting seawater intrusion in the coastal area. According to hydrochemistry results and geochemical modeling, the dominant factors in controlling the hydrochemical characteristics of groundwater are: (i water rock interaction with calcareous and calcareous-dolomitic lithologies; (ii seawater intrusion in the coastal area; (iii dissolution and/or precipitation of carbonate and (i.e. dolomite and calcite evaporate minerals (gypsum determined by saturation indexes; (iv mineral weathering process; (the high Mg/Ca ratio due to the weathering of Mg-rich dolomite.

  18. A case of extreme particulate matter concentrations over Central Europe caused by dust emitted over the southern Ukraine

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    W. Birmili

    2008-02-01

    Full Text Available On 24 March 2007, an extraordinary dust plume was observed in the Central European troposphere. Satellite observations revealed its origins in a dust storm in Southern Ukraine, where large amounts of soil were resuspended from dried-out farmlands at wind gusts up to 30 m s−1. Along the pathway of the plume, maximum particulate matter (PM10 mass concentrations between 200 and 1400 μg m−3 occurred in Slovakia, the Czech Republic, Poland, and Germany. Over Germany, the dust plume was characterised by a volume extinction coefficient up to 400 Mm−1 and a particle optical depth of 0.71 at wavelength 0.532 μm. In-situ size distribution measurements as well as the wavelength dependence of light extinction from lidar and Sun photometer measurements confirmed the presence of a coarse particle mode with diameters around 2–3 μm. Chemical particle analyses suggested a fraction of 75% crustal material in daily average PM10 and up to 85% in the coarser fraction PM10–2.5. Based on the particle characteristics as well as a lack of increased CO and CO2 levels, a significant impact of biomass burning was ruled out. The reasons for the high particle concentrations in the dust plume were twofold: First, dust was transported very rapidly into Central Europe in a boundary layer jet under dry conditions. Second, the dust plume was confined to a relatively stable boundary layer of 1.4–1.8 km height, and could therefore neither expand nor dilute efficiently. Our findings illustrate the capacity of combined in situ and remote sensing measurements to characterise large-scale dust plumes with a variety of aerosol parameters. Although such plumes from Southern Eurasia seem to occur rather infrequently in Central Europe, its unexpected features highlights the need to improve the description of dust emission, transport and transformation processes needs, particularly when facing the

  19. Central Java Southern part area deformation analysis by using GPS-CORS 2015

    Science.gov (United States)

    Yusfania, Meiriska; Anjasmara, Ira Mutiara; Hadi, Avrilina Luthfil; Pramudya, Bima

    2017-07-01

    Indonesia located on the convergence area of four active tectonic plates. Eurasia plate collides with Indo-Australia plate which forms subduction zone at the south of Java Island and forms the java island. Indo-Australia plate moving north by 7cm/year subducting under tectonic plate of Eurasia that relatively stated. As the results, tectonics and volcanic earthquakes are commonly occured at the boundary. In 2006, 5.9 Richter's scale earthquake, took place in Jogjakarta its surrounding, causing severe damage to the infrastructures. Therefore, Central Java has been marked as the seventh area which has high possibilities of earthquake in Indonesia. The aim of this research is to investigate deformation that happened at the South of Central Java using data of Continously Operating Reference Station of Indonesia (Ina-CORS) from 2013-2015. The deformation result is represented in the form of vectors and shifting velocity. Based on the result, it can be analysed that all six stations observed have the similar moving direction that is to the southeast with the horisontal velocity valued from 0.00910 to 0.01203 m/year. The vertical velocity of six stasions range from -0.01147 to 0.04354 m/year. From strain calculation using triangle segment it is found thet the value of compression bigger than extention value. Dominant extention value is in CSLO-CMGL-CBTL segment. The Value ɛ1: 0.01879 μstrain and ɛ2: -0.00997μstrain

  20. Geomorphic signature of active tectonics in the southern Abruzzi Periadriatic hilly belt (Central Italy)

    Science.gov (United States)

    Racano, Simone; Fubelli, Giandomenico; Centamore, Ernesto; Dramis, Francesco

    2016-04-01

    The geo-structural setting of the southern Abruzzi hilly belt that stretches from the northeastern front of the Maiella Massif to the Adriatic coast is characterized by deep-seated northeast verging thrusts masked by a thick cover of Late Pliocene-Middle Pleistocene marine deposits. Most authors consider this area tectonically inactive while only few of them support the hypothesis of its recent activity from the analysis of the river network pattern. Geological and geomorphological investigations carried out in the area have clearly shown the occurrence of surface deformations resulting from the continued activity of compressive tectonics up to recent times. The analysis of the study area by of a 10 m resolution DTM (using the open-source QGIS software) confirmed and supplemented field observations. Particularly significant in this context is the topographic setting of the alluvial strath terraces in the river valleys that develop transversally to the buried thrusts. In correspondence of these structures, topographic highs have grown up displacing the middle-Pleistocene planation surface developed on top of the hilly belt, from the Maiella piedmont to the coastal zone, and diverting laterally the river courses uphill. In the same places, as along the Alento and Foro rivers that cross by antecedence the grown up topographic highs, the long profiles of terraces bend eastward and the height difference between the terrace orders, essentially related all around the area to the Quaternary regional uplift, strongly increases. In some cases, surficial faults have lowered the terraces into graben troughs or have displaced them until assuming an uphill trend. This recent tectonic activity should be taken in account in assessing the seismic hazard of the study area.

  1. Hydrogeochemical processes controlling water and dissolved gas chemistry at the Accesa sinkhole (southern Tuscany, central Italy

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    Franco Tassi

    2014-05-01

    Full Text Available The 38.5 m deep Lake Accesa is a sinkhole located in southern Tuscany (Italy that shows a peculiar water composition, being characterized by relatively high total dissolved solids (TDS values (2 g L-1 and a Ca(Mg-SO4 geochemical facies. The presence of significant amounts of extra-atmospheric gases (CO2 and CH4, which increase their concentrations with depth, is also recognized. These chemical features, mimicking those commonly shown by volcanic lakes fed by hydrothermal-magmatic reservoirs, are consistent with those of mineral springs emerging in the study area whose chemistry is produced by the interaction of meteoric-derived waters with Mesozoic carbonates and Triassic evaporites. Although the lake has a pronounced thermocline, water chemistry does not show significant changes along the vertical profile. Lake water balance calculations demonstrate that Lake Accesa has >90% of its water supply from sublacustrine springs whose subterranean pathways are controlled by the local structural assessment that likely determined the sinking event, the resulting funnel-shape being then filled by the Accesa waters. Such a huge water inflow from the lake bottom (~9·106 m3 yr-1 feeds the lake effluent (Bruna River and promotes the formation of water currents, which are able to prevent the establishment of a vertical density gradient. Consequently, a continuous mixing along the whole vertical water column is established. Changes of the drainage system by the deep-originated waters in the nearby former mining district have strongly affected the outflow rates of the local mineral springs; thus, future intervention associated with the ongoing remediation activities should carefully be evaluated to preserve the peculiar chemical features of Lake Accesa.

  2. A detailed paleomagnetic and rock-magnetic investigation of the Matuyama-Bruhnes geomagnetic reversal recorded in tephra-paleosol sequence of Tlaxcala(Central Mexico

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    Ana Maria Soler-Arechalde

    2015-04-01

    Full Text Available Geomagnetic reversals are global phenomena, for about 50 years the paleomagnetists attempted to acquire as many detailed records as possible using the magnetic memory of sediments and lava flows. Yet, transitional field behavior remains poorly characterized largely because of sporadic aspect of volcanic eruptions. In some specific cases, paleosols such as those developed from alluvial or aeolian sediments, may also record the variations of the Geomagnetic Field across the polarity changes. Here, we report a detailed paleomagnetic and rock-magnetic investigation on some radiometrically dated chromic luvisols located in Central Mexico carrying detrital or chemical remanent magnetization. The research was developed in order i to demonstrate the primary origin of the magnetic remanence and ii to show that paleosoils are good candidates to provide a high resolution record of the behavior of geomagnetic field during reversals. The lower part of the paleosoil sequence shows a clearly defined reverse polarity magnetization followed by geomagnetically unstable transitional field and ended by normal polarity remanence. Our AMS and rock magnetic data suggest that magnetization is acquired during the initial stage of soil formation in context of active volcanic activity since magnetic fabric is essentially sedimentary and reverse and normal polarity paleodirections are almost antipodal. Titanomagnetites are identified as main magnetic carriers of rock-magnetic measurements including thermomagnetics and hysteresis cycles. We propose that the transition recorded in this study correspond to the B-M boundary, considering the K-Ar datings available at the sequence bottom and that the chromic luvisols are potentially good recorders of the paleosecular variation. The identification of the B-M boundary within the studied sequence has fundamental significance for improving the chronological scale of Tlaxcala paleosol-sedimentary sequence and its correlation with the

  3. SHRIMP zircon dating and LA-ICPMS Hf analysis of early Precambrian rocks from drill holes into the basement beneath the Central Hebei Basin, North China Craton

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    Yusheng Wan

    2014-07-01

    Full Text Available The Central Hebei Basin (CHB is one of the largest sedimentary basins in the North China Craton, extending in a northeast–southwest direction with an area of >350 km2. We carried out SHRIMP zircon dating, Hf-in-zircon isotopic analysis and a whole-rock geochemical study on igneous and metasedimentary rocks recovered from drill holes that penetrated into the basement of the CHB. Two samples of gneissic granodiorite (XG1-1 and gneissic quartz diorite (J48-1 have magmatic ages of 2500 and 2496 Ma, respectively. Their zircons also record metamorphic ages of 2.41–2.51 and ∼2.5 Ga, respectively. Compared with the gneissic granodiorite, the gneissic quartz diorite has higher ΣREE contents and lower Eu/Eu* and (La/Ybn values. Two metasedimentary samples (MG1, H5 mainly contain ∼2.5 Ga detrital zircons as well as late Paleoproterozoic metamorphic grains. The zircons of different origins have εHf (2.5 Ga values and Hf crustal model ages ranging from 0 to 5 and 2.7 to 2.9 Ga, respectively. Therefore, ∼2.5 Ga magmatic and Paleoproterozoic metasedimentary rocks and late Neoarchean to early Paleoproterozoic and late Paleoproterozoic tectono-thermal events have been identified in the basement beneath the CHB. Based on regional comparisons, we conclude that the early Precambrian basement beneath the CHB is part of the North China Craton.

  4. A detailed paleomagnetic and rock-magnetic investigation of the Matuyama-Bruhnes geomagnetic reversal recorded in tephra-paleosol sequence of Tlaxcala(Central Mexico)

    Science.gov (United States)

    Soler-Arechalde, Ana; Goguitchaichvili, Avtandyl; Carrancho, Ángel; Sedov, Sergey; Caballero-Miranda, Cecilia; Ortega, Beatriz; Solís, Berenice; Morales Contreras, Juan; Urrutia-Fucugauchi, Jaime; Bautista, Francisco

    2015-04-01

    Geomagnetic reversals are global phenomena, for about 50 years the paleomagnetists attempted to acquire as many detailed records as possible using the magnetic memory of sediments and lava flows. Yet, transitional field behavior remains poorly characterized largely because of sporadic aspect of volcanic eruptions. In some specific cases, paleosols such as those developed from alluvial or aeolian sediments, may also record the variations of the Geomagnetic Field across the polarity changes. Here, we report a detailed paleomagnetic and rock-magnetic investigation on some radiometrically dated chromic luvisols located in Central Mexico carrying detrital or chemical remanent magnetization. The research was developed in order i) to demonstrate the primary origin of the magnetic remanence and ii) to show that paleosoils are good candidates to provide a high resolution record of the behavior of geomagnetic field during reversals. The lower part of the paleosoil sequence shows a clearly defined reverse polarity magnetization followed by geomagnetically unstable transitional field and ended by normal polarity remanence. Our AMS and rock magnetic data suggest that magnetization is acquired during the initial stage of soil formation in context of active volcanic activity since magnetic fabric is essentially sedimentary and reverse and normal polarity paleodirections are almost antipodal. Titanomagnetites are identified as main magnetic carriers of rock-magnetic measurements including thermomagnetics and hysteresis cycles. We propose that the transition recorded in this study correspond to the B-M boundary, considering the K-Ar datings available at the sequence bottom and that the chromic luvisols are potentially good recorders of the paleosecular variation. The identification of the B-M boundary within the studied sequence has fundamental significance for improving the chronological scale of Tlaxcala paleosol-sedimentary sequence and its correlation with the global proxies.

  5. From source to sink in central Gondwana: Exhumation of the Precambrian basement rocks of Tanzania and sediment accumulation in the adjacent Congo basin

    Science.gov (United States)

    Kasanzu, Charles Happe; Linol, Bastien; de Wit, Maarten J.; Brown, Roderick; Persano, Cristina; Stuart, Finlay M.

    2016-09-01

    Apatite fission track (AFT) and (U-Th)/He (AHe) thermochronometry data are reported and used to unravel the exhumation history of crystalline basement rocks from the elevated (>1000 m above sea level) but low-relief Tanzanian Craton. Coeval episodes of sedimentation documented within adjacent Paleozoic to Mesozoic basins of southern Tanzania and the Congo basin of the Democratic Republic of Congo indicate that most of the cooling in the basement rocks in Tanzania was linked to erosion. Basement samples were from an exploration borehole located within the craton and up to 2200 m below surface. Surface samples were also analyzed. AFT dates range between 317 ± 33 Ma and 188 ± 44 Ma. Alpha (Ft)-corrected AHe dates are between 433 ± 24 Ma and 154 ± 20 Ma. Modeling of the data reveals two important periods of cooling within the craton: one during the Carboniferous-Triassic (340-220 Ma) and a later, less well constrained episode, during the late Cretaceous. The later exhumation is well detected proximal to the East African Rift (70 Ma). Thermal histories combined with the estimated geothermal gradient of 9°C/km constrained by the AFT and AHe data from the craton and a mean surface temperature of 20°C indicate removal of up to 9 ± 2 km of overburden since the end of Paleozoic. The correlation of erosion of the craton and sedimentation and subsidence within the Congo basin in the Paleozoic may indicate regional flexural geodynamics of the lithosphere due to lithosphere buckling induced by far-field compressional tectonic processes and thereafter through deep mantle upwelling and epeirogeny tectonic processes.

  6. LATE TRIASSIC (LATE NORIAN-RHAETIAN RADIOLARIANS FROM THE ANTALYA NAPPES, CENTRAL TAURIDES, SOUTHERN TURKEY

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    UGUR KAGAN TEKIN

    2002-11-01

    Full Text Available The Hocaköy section measured from the Alakirçay Nappe (middle nappe of the Antalya Nappes contain rich radiolarian fauna ranging from late Norian (Late Triassic to middle-late Cenomanian (mid Cretaceous. At the basal part of the section, the Late Triassic (late Norian-Rhaetian Gökdere Formation is characterized by gray to beige cherty limestone at the base and pinkish red chert- gray to beige limestone alternation at the top, with moderately to well-preserved radiolarians in the red chert beds. The overlying Jurassic - Middle Cretaceous Hocaköy Radiolarite is mainly represented by chert-mudstone alternations with some limestone interlayers. Radiolarians of the Gökdere Formation can be well correlated with that of the fauna from the Mino Terrane, central Japan and the fauna from the Queen Charlotte Islands, British Columbia, Canada. Four radiolarian zones from central Japan are recognized in the fauna obtained from Gökdere Formation such as “Praemesosaturnalis multidentatus Lowest Occurrence Zone (TR8A” (late Norian, “Praemesosaturnalis pseudokahleri Lowest Occurrence Zone (TR8B” (late Norian, ? “ Skirt F lowest Occurrence Zone (TR8C” (late Norian-Rhaetian and partly “Haeckelicyrtium breviora Taxon Range Zone (TR8D” (Rhaetian. In comparison with the Queen Charlotte fauna, the two zones “Betraccium deweveri Zone” (late Norian and “Proparvicingula moniliformis Zone” (early Rhaetian are also encountered in the Gökdere Formation. Radiolarians of the uppermost part of the Gökdere Formation indicate that “Globolaxtorum tozeri Zone” defined in Queen Charlotte Islands corresponding to the late Rhaetian, is not present in the section. Five new taxa, Capnuchosphaera okayi, Bistarkum rhaeticum, Praemesosaturnalis heilongjiangensis aksekiensis, P. nobleae, Veghicyclia sanfilippoae were determined within the late Norian-Rhaetian radiolarian fauna of the Gökdere Formation in Hocaköy section.   

  7. 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.

  8. Low-Frequency Earthquakes Associated with the Late-Interseismic Central Alpine Fault, Southern Alps, New Zealand

    Science.gov (United States)

    Baratin, L. M.; Chamberlain, C. J.; Townend, J.; Savage, M. K.

    2016-12-01

    field in the central Southern Alps.

  9. A ˜ 700 Ma Sm Nd garnet whole rock age from the granulite facies Central Kaoko Zone (Namibia): Evidence for a cryptic high-grade polymetamorphic history?

    Science.gov (United States)

    Jung, S.; Kröner, A.; Kröner, S.

    2007-09-01

    Continental collision of the Kalahari and the Congo craton in Africa and the Rio de la Plata Craton in South America resulted in a structurally complex Neoproterozoic belt system, the Kaoko-Dom Feliciano-Ribeira belt. It is uncertain whether these three cratons collided more or less simultaneously during one single orogenic event at ˜ 580-550 Ma or whether the belt owe its structural and metamorphic features to several so far poorly constrained events. The Kaoko Belt (NW Nambia), representing the belt system between the southern Congo Craton and the Rio de la Plata Craton, is an ideal object to study these complexities. Within this belt, high-grade meta-igneous and metasedimentary rocks of the sillimanite-K-feldspar zone contain large garnet porphyroblasts that grew at ca. 730 ± 10 °C at 6.7 ± 1.2 kbar during peak metamorphic granulite-facies conditions. A Sm-Nd garnet-whole rock errorchron ( n = 7, MSWD = 6.0) obtained on a siliceous metasediment yielded an unexpected old age of 692 ±14 Ma which is interpreted as an inherited metamorphic age of an older granulite facies event. It is evident that the dated garnets survived the younger high-grade granulite facies metamorphism that occurred between ca. 570 and 520 Ma and preserved their old Sm-Nd isotope systematics implying that the closure temperature for Sm-Nd in garnet is higher than ca. 730 °C in this case. These results imply fast cooling rates at different times during the Pan-African orogeny that prevent isotopic homogenization at sample scale. Moreover, it is suggestive that trace element (REE) diffusion in garnet is considerably slower than major element diffusion. From a regional point of view, it is possible that these specific siliceous metasedimentary rocks may be unrelated to the Pan-African metamorphic evolution of the Kaoko Belt between 570 and 520 Ma and may represent lithological units that belong to so far unrecognized terranes in the Kaoko Belt.

  10. Tectonics, climate and surface processes of the southern central Andes: insights from stable C isotopes and sedimentary environments

    Science.gov (United States)

    Strecker, M. R.; Chamberlain, P. C.; Hilley, G. E.; Mulch, A.; Schmitt, A.; Uba, C.

    2007-12-01

    The Puna of the southern central Andes comprises a high-elevation, semi-arid to arid low-relief, which forms an integral part of the Altiplano orogenic plateau. Internally, the plateau is compartmentalized into sedimentary basins and intervening basement rages that were uplifted in a diachronous manner throughout the present plateau region, similar to ongoing deformation and uplift along the current plateau margin in the broken foreland. A unifying feature of the Puna-Altiplano plateau is that its location corresponds to sectors of the landscape in which channels have generally failed to incise deeply into basin sediments or through surrounding basement ranges. Importantly, in both areas the local base-level is hydrologically isolated from the foreland. This isolation occurs where the incising power of regional drainage systems has been greatly reduced due to a combination of diminished precipitation related to regional climate and local orography, and exposure of bedrock that is resistant to fluvial incision. This hydrologic isolation from the foreland restricts evacuation of eroded material, consequently leading to internal drainage and a reduction of relief between basins and the surrounding peaks. Thus, while a variety of deformation styles and possibly combinations of different processes may have generated the high elevations and structural compartmentalization associated with the plateau, the low-relief character of the plateau may be a geomorphic, rather than a tectonic phenomenon. Basins similar to those in the Puna exist along the plateau margin, although these basins remain only transiently isolated and internally drained due to the proximity to high precipitation gradients which were established due to orographic barriers related to Pliocene uplift. These barriers focus precipitation and erosion and promote headward erosion, stream capture and ultimately basin exhumation and connection to the foreland, which prevents these areas to become incorporated

  11. Cannabinoid Type-1 Receptor Gene Polymorphisms Are Associated with Central Obesity in a Southern Brazilian Population

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    Janaína P. Jaeger

    2008-01-01

    Full Text Available The CB1 cannabinoid receptor and its endogenous ligands, the endocannabinoids, are involved in energy balance control, stimulating appetite and increasing body weight in wasting syndromes. Different studies have investigated the relationship between polymorphisms of the cannabinoid receptor 1 (CNR1 gene and obesity with conflicting results. In the present study, we investigated the 1359G/A (rs1049353, 3813A/G (rs12720071 and 4895A/G (rs806368 polymorphisms in the CNR1 gene in a Brazilian population of European descent. To verify the association between these variants and obesity-related traits in this population, 756 individuals were genotyped by PCR-RFLP methods. The 4895G allele was associated with waist to hip ratio (WHR (P = 0.014; P = 0.042 after Bonferroni correction. An additive effect with the GAA haplotype was associated with WHR (P = 0.028, although this statistical significance disappeared after Bonferroni correction (P = 0.084. No significant association was observed between the genotypes of the 1359G/A and 3813A/G polymorphisms and any of the quantitative variables investigated. Our findings suggest that CNR1 gene polymorphism is associated with central obesity in this Brazilian population of European ancestry.

  12. De novo malignancies following liver transplantation: results from a multicentric study in central and southern Italy, 1990-2008.

    Science.gov (United States)

    Ettorre, G M; Piselli, P; Galatioto, L; Rendina, M; Nudo, F; Sforza, D; Miglioresi, L; Fantola, G; Cimaglia, C; Vennarecci, G; Vizzini, G B; Di Leo, A; Rossi, M; Tisone, G; Zamboni, F; Santoro, R; Agresta, A; Puro, V; Serraino, D

    2013-09-01

    The objective of this study was to quantify incidence rates (IR) and risks of de novo tumors (except nonmelanoma skin cancers) in patients who underwent orthotopic liver transplantation (OLT) in central and southern Italy. Data were collected on 1675 patients (75.5% males) who underwent OLT in six Italian transplantation centers in central and southern Italy (1990-2008). The time at risk of cancer (person years [PY]) was computed from OLT to the date of cancer diagnosis, death, or last follow-up, whichever occurred first. The number of observed cancer cases were compared with the expected one using data from population-based cancer registries. We computed gender- and age-standardized incidence ratios (SIRs) and 95% confidence intervals (CIs). During 10,104.3 PYs (median follow-up, 5.2 years), 98 patients (5.9% of the total) were diagnosed with a de novo malignancy (for a total of 100 diagnoses). Twenty-two of these cancers were post-transplantation lymphoproliferative disorders (PTLD; 18 non-Hodgkin lymphoma [NHL] and 2 Hodgkin's lymphoma [HL]), 6 were Kaposi's sarcoma (KS), and 72 were solid tumors (19 head and neck [H&N], 13 lung, 11 colon-rectum, 6 bladder, and 4 melanoma). The overall incidence was 9.9 cases/10(3) PYs, with a 1.4-fold significantly increased SIR (95% CI, l.2-1.7). Significantly increased SIRs were observed for KS (37.3), PTLD (3.9), larynx (5.7), melanoma (3.1), tongue (7.1), and H&N (4.5) cancers. These results confirmed that OLT patients are at greater risk for cancer, mainly malignancies either virus-associated or related to pre-existent factors (eg, alcohols). These observations point to the need to improve cancer surveillance after OLT. The on-going enrollment of patients in the present cohort study will help to elucidate the burden of cancer after OLT and better identify risk factors associated with its development. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. The Effect of Season-Long Temperature Increases on Rice Cultivars Grown in the Central and Southern Regions of China

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    Zhiyuan Yang

    2017-11-01

    Full Text Available Rice production is challenged by the asymmetric increases in day and night temperatures. Efforts are required to improve our understanding of the impact of climate change on rice production. To this end, 2-year experiment was conducted to evaluate the response of mid-season rice growth in the central and southern regions of China to elevated temperatures. Four replicates of four widely planted indica rice cultivars (Huanghuazhan: HHZ; Shanyou63: SY63; Yangliangyou6: YLY6; Liangyoupeijiu: LYPJ were subjected to four elevated-temperature treatments (control: ambient temperature; NW: night-time warming; DW: daytime warming; AW: all-day warming generated by an open-top hot-blast system under field conditions. This apparatus causes an ~2°C increase in the rice canopy temperature. Of all the elevated-temperature treatments, AW was the most devastating treatment for all rice cultivars, negatively affecting nearly all of investigated parameters, including grain yield and its components, dry matter accumulation, biomass, and harvest index (HI. The AW treatment decreased the grain yield by 11–35% and 43–78% in 2015 and 2016, respectively. No significant reduction in the grain yield was observed in the DW and NW treatments in 2015. However, the grain yield was decreased in DW and NW treatments by 20–52% and 18–55%, respectively, in 2016. Furthermore, the temperature-driven degradation of pollen viability, the number of pollen grains adhering to the stigma and pollen germination on the stigma caused spikelet sterility and thereby decreased the grain yield. The YLY6 and SY63 cultivars performed better than the HHZ and LYPJ cultivars with respect to grain yield and its components in all elevated-temperature treatments in both years. However, 42.97 and 61.01% reductions still occurred for the SY63 and YLY6 cultivars, respectively, in the AW treatment in 2016. The above results suggested that the elevated temperature may cause a noteworthy reduction in

  14. Paleomagnetic and AMS studies of the El Castillo ignimbrite, central-east Mexico: Source and rock magnetic nature

    Science.gov (United States)

    Alva-Valdivia, L. M.; Agarwal, A.; Caballero-Miranda, C.; García-Amador, B. I.; Morales-Barrera, W.; Rodríguez-Elizarraráz, S.; Rodríguez-Trejo, A.

    2017-04-01

    Lithological, petromagnetic, paleomagnetic and magnetic fabric studies are employed to determine the flow direction and the location of the source of the, 2.44 to 2.21 Ma, El Castillo ignimbrite in the central-east Mexico. Based on the increasing matrix to pumice ratio and decreasing pumice size, the ignimbrite field is divided into the northwestern, central and south-southeastern sectors. Lithological comparisons among the three sectors reveal that the ignimbrite had flowed from NW to SE, and the source is in the NW part of the study area. Thermomagnetic results concur with the increasing matrix proportions from the proximal to the distal sector. The coercivity and magnetization ratios of the hysteresis parameters are lower in the SE sector than in the NW and central sectors. The dominant flow direction inferred through magnetic fabrics, at most sites, is NW to SE, which coincides with the direction inferred from lithological comparisons. However, at some sites magnetic fabrics demonstrate flow towards ENE or other various directions. The paleomagnetic analysis and field observations reveal that these anomalous directions are a consequence of anticlockwise block rotation and tilting due to normal and lateral faulting in the region.

  15. A new focus of cutaneous leishmaniasis in the central area of Paraná State, southern Brazil.

    Science.gov (United States)

    Soccol, Vanete Thomaz; de Castro, Edilene Alcântara; Schnell e Schühli, Guilherme; de Carvalho, Yanê; Marques, Ellen; Pereira, Elisângela de Fátima; Alcantara, Fernanda de Souza; Machado, Angela Maria; Kowalthuk, Wolodymir; Membrive, Norberto; Luz, Ennio

    2009-09-01

    We report a new endemic zone of cutaneous leishmaniasis (CL) in the central area of the State of Paraná (Municipality of Prudentópolis), in southern Brazil. This region was not previously considered endemic for CL, and this work constitutes the first report of CL endemicity there. Leishmaniasis was confirmed by smear, culture, and ELISA. Parasites were isolated and identified by random amplification of polymorphic DNA (PCR-RAPD). Phylogeographical analysis, based on two different criteria, was able to distinguish between RAPD profiles from different geographical regions. In total, 100 patients were diagnosed with leishmaniasis by culture and serology methods. The reported incidence rate was 4.32%. Of the 100 patients, 92% of the patients had single lesions, and 79.98% of these lesions were located on their limbs. The fact that 61% of patients were male rural workers points to an extradomiciliar type of transmission. In houses where human leishmaniasis was diagnosed, 29% of the dogs presented anti-Leishmania antibodies. A total of 1663 phlebotomines, representing 5 species, were captured in the studied area with CDC-like light minitraps. Lutzomyia intermedia s.l. was the most prevalent species (94.40%). The isolated parasites were grouped with Leishmania (V.) braziliensis. The epidemiological implications are discussed in the present article.

  16. Zooplankton of 15 lakes in the Southern Central Alps: comparison of recent and past (pre-ca 1850 AD communities

    Directory of Open Access Journals (Sweden)

    Michele ARMIRAGLIO

    2002-08-01

    Full Text Available We report the results of a study on modern zooplankton community as well as on Cladocera sub-fossil remains from 15 high altitude lakes in the Italian Central-Southern Alps, aimed at investigating changes after 19th Century industrialisation. Present-day communities were compared to those of the pre-industrial period (approximately pre-1850 AD. Numerical analysis suggests a relationship between environmental variables, such as pH or total phosphorus, and the cladoceran community structure. However, as found in previous studies, another important environmental variable not included in numerical analysis, is presence or absence of fish. Arctodiaptomus alpinus was not found at pH levels lower than 6.21, while Daphnia lacked from lakes where fish were regularly introduced. Daphnia re-colonised the today fish-less Lago Paione Inferiore, whereas in the past, with a regular introduction of fish, only rotifers and a few Cyclops were found. The re-colonisation is interpreted by regarding the three Paione lakes as parts of a cascade system, where a transport from the upper Lago Paione Superiore to the lower Lago Paione Inferiore can take place, and the sediments represent a kind of an "egg bank".

  17. Geotechnical database and descriptions of permafrost monitoring sites established 2006-07 in the central and southern Mackenzie corridor

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.L.; Chartrand, T.N.; Nguyen, T.-N.; Riseborough, D.W.; Ednie, M.; Ye, S. [Natural Resources Canada, Ottawa, ON (Canada). Geological Survey of Canada

    2009-07-01

    Permafrost is an important aspect of the Mackenzie Valley that impacts upon the natural and socio-economic environments in the region. In order to address gaps in baseline environmental information in the Mackenzie Valley associated with proposed transportation and resource development corridors, the Geological Survey of Canada of Natural Resources Canada conducted a major field program between 2005 and 2007. Forty-three boreholes were drilled in the Mackenzie corridor, located south of Fort Good Hope. Thirty-three of these holes were preserved and instrumented with temperature cables. A Microsoft Access relational database was used to compile geotechnical information and initial ground temperature data from these boreholes. This report presented a geotechnical database and descriptions of permafrost monitoring sites in the central and southern Mackenzie corridor. It discussed the site location and general description, and presented the database structure and graphical presentations of borehole logs and initial thermal data. The information provided in the report has met the needs of several users, including those involved in planning northern development, infrastructure design and regulatory agencies. 14 refs., 2 tabs., 2 figs., 1 appendix.

  18. Clinopyroxene trace element compositions of cumulate mafic rocks and basalts from the Hercynian Moroccan Central Meseta: Petrogenetic implications

    Science.gov (United States)

    Driouch, Y.; Béziat, D.; Grégoire, M.; Laguenini, F.; Abbou, M. Ben; Ntarmouchant, A.; Roddaz, M.; Dahire, M.; Bennouna, A.; Belkasmi, M.; Brusset, S.; Debat, P.

    2010-02-01

    In the Fourhal foreland basin, in the north-eastern part of the Marrocan Central Meseta, mafic series are represented by basalts interbedded with Early Namurian turbidites and by numerous mafic sills, including the Marziqallal sill detailed here. The study of the trace element compositions of the clinopyroxenes, a ubiquitous mineral in the gabbroic sill and basalts, indicate that these two formations are derived from a similar parental magma. This magma evolved following a general fractional crystallization process involving the cumulation of clinopyroxene, then of ilmenite, occurring within the sill and having a leading role in the composition of the associated basalts. Calculated parental melts inferred from clinopyroxene analyses from the various cumulative units of the sill have trace element patterns similar to the one found for the basaltic flows. These patterns are compatible with magma and clinopyroxene compositions from a subduction-related geotectonic setting.

  19. Socioeconomic status as a risk factor for HIV infection in women in East, Central and Southern Africa: a systematic review.

    Science.gov (United States)

    Wojcicki, Janet Maia

    2005-01-01

    This is a critical, systematic review of the relationship between socioeconomic status (SES) and HIV infection in women in Southern, Central and Eastern Africa. In light of the interest in micro-credit programmes and other HIV prevention interventions structured to empower women through increasing women's access to funds and education, this review examines the epidemiological and public health literature, which ascertains the association between low SES using different measurements of SES and risk of HIV infection in women. Also, given the focus on structural violence and poverty as factors driving the HIV epidemic at a structural/ecological level, as advocated by Paul Farmer and others, this study examines the extent to which differences in SES between individuals in areas with generalized poverty affect risk for SES. Out of 71 studies retrieved, 36 studies met the inclusion criteria including 30 cross-sectional, one case-control and five prospective cohort or nested case-control studies. Thirty-five studies used at least one measurement of female's SES and fourteen also included a measurement of partner's SES. Studies used variables measuring educational level, household income and occupation or employment status at the individual and neighbourhood level to ascertain SES. Of the 36 studies, fifteen found no association between SES and HIV infection, twelve found an association between high SES and HIV infection, eight found an association between low SES and HIV infection and one was mixed. In interpreting these results, this review examines the role of potential confounders and effect modifiers such as history of STDs, number of partners, living in urban or rural areas and time and location of study in sub-Saharan Africa. It is argued that STDs and number of partners are on the causal pathway under investigation between HIV and SES and should not be adjusted as confounders in any analysis. In conclusion, it is argued that in low-income sub-Saharan Africans

  20. Gastric adenocarcinoma trends in the central region of Rio Grande do Sul (Southern Brazil: what has changed in 25 years?

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    Alexandre Rampazzo

    2012-09-01

    Full Text Available CONTEXT: Gastric cancer is the fourth most common malignancy in the world. Its incidence varies greatly by geographic region. The highest rate is in Eastern Asia, mainly in Japan and China. In Brazil, gastric cancer is the third most common cancer in males and the fifth most common cancer in females. Rio Grande do Sul state, in Southern Brazil, has similar figures. The main histological type of gastric cancer is adenocarcinoma. OBJECTIVE: To assess the trends of this cancer over 25 years in a reference center in central Rio Grande do Sul. METHODS: We reviewed the records of upper gastrointestinal endoscopies performed at the University Hospital of Santa Maria, RS, between 1986 and 2010. We evaluated the incidence, age and gender distribution, anatomical subsite and histological subtype of gastric cancer throughout this 25-year period. RESULTS: We identified histologically confirmed primary gastric adenocarcinoma in 335 (1.6% of the 20,521 patients who underwent upper gastrointestinal endoscopy during the study period. The mean age of patients was 62.4 (± 13.0 years, and 67.8% were male (a male: female ratio of 2.0:1. Cardia cancer accounted for 14.3% of the cases, and non-cardia cancer accounted for 85.7%. According to Lauren's classification, 48.1% were intestinal subtype and 40.9% were diffuse subtype. There were no differences in mean age or gender distribution by anatomical location or histological subtype. There was also no difference in the proportions of histological subtypes by anatomical location. Over the 25-year period, there was no change in the anatomical distribution of tumors, but there was a significant decrease in the intestinal subtype and a steady increase in the diffuse subtype (P = 0.02. The subset of 39 patients (11.6% who presented at < 45 years of age was more likely to be female and to have tumors of the diffuse subtype than was the total series of patients. CONCLUSIONS: Over this 25-year period, there were no

  1. Rock fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Brown, W.S.; Green, S.J.; Hakala, W.W.; Hustrulid, W.A.; Maurer, W.C. (eds.)

    1976-01-01

    Experts in rock mechanics, mining, excavation, drilling, tunneling and use of underground space met to discuss the relative merits of a wide variety of rock fragmentation schemes. Information is presented on novel rock fracturing techniques; tunneling using electron beams, thermocorer, electric spark drills, water jets, and diamond drills; and rock fracturing research needs for mining and underground construction. (LCL)

  2. The effects of water rock interaction and the human activities on the occurrence of hexavalent chromium in waters. The case study of the Psachna basin, Central Euboea, Greece.

    Science.gov (United States)

    Vasileiou, Eleni; Perraki, Maria; Stamatis, George; Gartzos, Efthimios

    2014-05-01

    High concentrations of heavy metals, particularly of the toxic hexavalent chromium, are recorded in surface and ground waters in many areas, and constitute one of the most severe environmental problems nowadays. The natural genesis of chromium is associated with the geological environment (peridotites and serpentintites). Chromium is structured in many minerals, mainly in spinel (e.g. chromite), in silicate minerals such as phyllosilicate serpentine minerals, chlorite, talc and chain-silicate minerals of pyroxene and amphibole group. Chromium is found in two forms in soils, waters and rocks, the hexavalent and the trivalent one. The relation between Cr(III) and Cr(VI) strongly depends on pH and oxidative properties of the area; however, in most cases, Cr(III) is the dominating variant. The natural oxidation of trivalent to hexavalent chromium can be achieved by manganese oxides, H2O2, O2 gas and oxy-hydroxides of trivalent iron. Anthropogenic factors may also cause the process of chromium's oxidation. In the Psachna basin, Central Euboea, Greece, high concentrations of hexavalent chromium were recently measured in spring- and drill- waters. In this work, we study the effect of the geological environment and of the anthropogenic activities on the water quality with emphasis on chromium. A detailed geochemical, petrological and mineralogical study of rocks and soils was carried out by means of optical microscopy, XRF, XRD and SEM/EDS. Ground and surface water samples were physically characterized and hydrochemically studied by means of ICP and AAF. Combined result evaluation indicates a natural source for the trivalent chromium in waters, attributed to the alteration of Cr-bearing minerals of the ultramafic rocks. However the oxidation of trivalent to hexavalent chromium results from anthropogenic activities, mainly from intensive agricultural activities and the extensive use of fertilizers and pesticides causing nitrate pollution in groundwater. It has been shown

  3. Classification of Debris-Covered Glaciers and Rock Glaciers in the Andes of Central Chile - An Approach Integrating Field Measurements, High-Resolution Satellite Imagery, and Coring Data to Estimate Water Resources

    Science.gov (United States)

    Janke, J. R.; Bellisario, A. C.; Ferrando, F. A.

    2014-12-01

    In the Dry Andes of Chile (17 to 35° S), debris-covered glaciers and rock glaciers are differentiated from "true" glaciers based on the percentage of surface debris cover, thickness of surface debris, and ice content. These landforms are more numerous than glaciers in the Central Andes; however, there are often omitted from inventories. Glaciers, debris covered glaciers, and rock glaciers are being removed by mining, while agricultural expansion and population growth have placed an additional demand on water resources. As a result, it is important to identify and locate these features to implement sustainable solutions. The objective of this study is to develop a classification system to identify debris-covered glaciers and rock glaciers based on satellite imagery interpretation. The classification system is linked to field observations and measurements of ice content. Debris covered glaciers have three subclasses: surface coverage of semi (Class 1) and fully covered (Class 2) glaciers differentiates the first two forms, whereas debris thickness is critical for Class 3 when glaciers become buried with more than 3 m of surface debris. The amount of ice decreases from more than 85%, to 65-85%, to 45-65% for semi, fully, and buried debris-covered glaciers, respectively. Rock glaciers are characterized by three stages. Class 4 rock glaciers have pronounced transverse ridges and furrows that arch across the surface, which indicate flow produce via ice. Class 5 rock glaciers have ridges and furrows that appear linear in the direction of flow, and Class 6 rock glaciers have subdued surface topography that has been denudated as the rock glacier ceases movement. Ice content decreases from 25-45% ice, to 10-25% ice, to less than 10% ice from Class 4 to 6, respectively. The classification scheme can be used to identify and map debris covered glaciers and rock glaciers to create an inventory to better estimate available water resources at the basin-wide scale.

  4. A new genetic interpretation for the Caotaobei uranium deposit associated with the shoshonitic volcanic rocks in the Hecaokeng ore field, southern Jiangxi, China

    Directory of Open Access Journals (Sweden)

    Dong-Sheng Yang

    2017-03-01

    Full Text Available Combined with in-situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS zircon UPb geochronology, published and unpublished literature on the Caotaobei uranium deposit in southern Jiangxi province, China, is re-examined to provide an improved understanding of the origin of the main ore (103 Ma. The Caotaobei deposit lies in the Hecaokeng ore field and is currently one of China's largest, volcanic-related uranium producers. Unlike commonly known volcanogenic uranium deposits throughout the world, it is spatially associated with intermediate lavas with a shoshonitic composition. Uranium mineralization (pitchblende occurs predominantly as veinlets, disseminations, and massive ores, hosted by the cryptoexplosive breccias rimming the Caotaobei crater. Zircons from one latite define four distinct 206Pb/238U age groups at 220–235 Ma (Triassic, 188 Ma (Early Jurassic, 131–137 Ma (Early Cretaceous, and 97–103 Ma (Early-Late Cretaceous transition, hereafter termed mid-Cretaceous. The integrated age (134 ± 2 Ma of Early Cretaceous zircons (group III is interpreted as representing the time of lava emplacement. The age data, together with the re-examination of literature, does not definitively support a volcanogenic origin for the generation of the deposit, which was proposed by the previous workers based mainly on the close spatial relationship and the age similarity between the main ore and volcanic lavas. Drill core and grade-control data reveal that rich concentrations of primary uranium ore are common around the granite porphyry dikes cutting the lavas, and that the cryptoexplosive breccias away from the dikes are barren or unmineralized. These observations indicate that the emplacement of the granite porphyries exerts a fundamental control on ore distribution and thus a genetic link exists between main-stage uranium mineralization and the intrusions of the dikes. Zircon overgrowths of mid-Cretaceous age (99.6

  5. Cave bats of the central west coast and southern section of the Northwest Panay Peninsula, Panay Island, the Philippines

    Directory of Open Access Journals (Sweden)

    A. Mould

    2012-09-01

    Full Text Available Bats (order Chiroptera form a large proportion of the species-rich mammalian fauna of the Philippines, and while the threats posed to these animals are well documented, for many species there is currently insufficient data to enable even a basic assessment of their conservation status. This is true for Panay Island, located in the Western Visayas region of the archipelago, where the need for surveying remaining suitable bat habitat has been identified as a priority. Between 5 April and 9 May 2011 a survey of 21 caves was undertaken on Panay, along the central section of the west coast of the island and within the southern section of the Northwest Panay Peninsula. Survey methods included visual observations, emergence counts and the recording of echolocation calls. Of the caves surveyed, 19 were found to support bats or show signs of their use, and at least 12 different species were observed. Three large maternity colonies of the Common Rousette Rousettus amplexicaudatus and two of the Dusky Roundleaf Bat Hipposideros ater were noted as having particular significance in terms of their conservation value for local populations. Potential maternity colonies of Asian Lesser False Vampire Megaderma spasma, Black-bearded Tomb Bat Taphozous melanopogon and Diadem Roundleaf Bat Hipposideros diadema were also observed but not confirmed. M. spasma was the most frequently encountered species, occurring in small numbers at five different caves. Other species/genera encountered in small numbers were the Arcuate Horseshoe Bat Rhinolophus arcuatus, Common Short-nosed Fruit Bat Cynopterus brachyotis, Philippine Sheath-tailed Bat Emballonura alecto, Yellow-faced Horseshoe Bat Rhinolophus virgo, Bent-wing (Miniopterus and Myotis bat species, and at least one other Horseshoe (Rhinolophus bat species. Ten of the caves were confirmed to support multiple bat species. An indication of current threats and recommendations for further survey and management priorities are

  6. Strongly-sheared wind-forced currents in the nearshore regions of the central Southern California Bight

    Science.gov (United States)

    Noble, Marlene A.; Rosenberger, Kurt; Robertson, George L.

    2015-01-01

    Contrary to many previous reports, winds do drive currents along the shelf in the central portion of the Southern California Bight (SCB). Winds off Huntington Beach CA are the dominant forcing for currents over the nearshore region of the shelf (water depths less than 20 m). Winds control about 50–70% of the energy in nearshore alongshelf surface currents. The wind-driven current amplitudes are also anomalously high. For a relatively weak 1 dyne/cm2 wind stress, the alongshelf surface current amplitudes in this region can reach 80 cm/s or more. Mid-depth current amplitudes for the same wind stress are around 30–40 cm/s. These wind-driven surface current amplitudes are much larger than previously measured over other nearshore shelf regions, perhaps because this program is one of the few that measured currents within a meter of the surface. The near-bed cross-shelf currents over the nearshore region of the Huntington Beach shelf have an Ekman response to winds in that they upwell (downwell) for down (up) coast winds. This response disappears further offshore. Hence, there is upwelling in the SCB, but it does not occur across the entire shelf. Subthermocline water in the nearshore region that may contain nutrients and plankton move onshore when winds are southeastward, but subthermocline water over the shelf break is not transported to the beach. The currents over the outer shelf are not predominately controlled by winds, consistent with previous reports. Instead, they are mainly driven by cross-shelf pressure gradients that are independent of local wind stress.

  7. Pioneer study of population genetics of Rhodnius ecuadoriensis (Hemiptera: Reduviidae) from the central coastand southern Andean regions of Ecuador.

    Science.gov (United States)

    Villacís, Anita G; Marcet, Paula L; Yumiseva, César A; Dotson, Ellen M; Tibayrenc, Michel; Brenière, Simone Frédérique; Grijalva, Mario J

    2017-09-01

    Effective control of Chagas disease vector populations requires a good understanding of the epidemiological components, including a reliable analysis of the genetic structure of vector populations. Rhodnius ecuadoriensis is the most widespread vector of Chagas disease in Ecuador, occupying domestic, peridomestic and sylvatic habitats. It is widely distributed in the central coast and southern highlands regions of Ecuador, two very different regions in terms of bio-geographical characteristics. To evaluate the genetic relationship among R. ecuadoriensis populations in these two regions, we analyzed genetic variability at two microsatellite loci for 326 specimens (n=122 in Manabí and n=204 in Loja) and the mitochondrial cytochrome b gene (Cyt b) sequences for 174 individuals collected in the two provinces (n=73 and=101 in Manabí and Loja respectively). The individual samples were grouped in populations according to their community of origin. A few populations presented positive FIS, possible due to Wahlund effect. Significant pairwise differentiation was detected between populations within each province for both genetic markers, and the isolation by distance model was significant for these populations. Microsatellite markers showed significant genetic differentiation between the populations of the two provinces. The partial sequences of the Cyt b gene (578bp) identified a total of 34 haplotypes among 174 specimens sequenced, which translated into high haplotype diversity (Hd=0.929). The haplotype distribution differed among provinces (significant Fisher's exact test). Overall, the genetic differentiation of R. ecuadoriensis between provinces detected in this study is consistent with the biological and phenotypic differences previously observed between Manabí and Loja populations. The current phylogenetic analysis evidenced the monophyly of the populations of R. ecuadoriensis within the R. pallescens species complex; R. pallescens and R. colombiensis were more

  8. Hard-rock hydrotectonics using geographic information systems in the central highlands of Eritrea: Implications for groundwater exploration

    Science.gov (United States)

    Solomon, Semere; Ghebreab, Woldai

    2008-01-01

    SummaryIn the central highlands of Eritrea, the fractures derived as lineaments from digitally enhanced Landsat TM images are grouped based on their tectonic origins and relative ages into three major sets of geological structures, Set 1, Set 2 and Set 3. Set 1 comprises the oldest NNE-SSW and NW-SE trending tensile lineaments, Set 2 is N-S and WNW-ESE and Set 3 is NE-SW and ENE-WSW. Both Set 2 and Set 3 are conjugate shear fractures. Frequency of groundwater occurrence (producing wells close to fracture lineaments), well yield and distance or locations of well data from the fractures are the main parameters considered in the analysis using geographic information systems (GIS). In the Set 2 and Set 3 shear fractures, well yields at distances of 0-60 m to lineaments are low while well yields at a distance of about 90-120 m away from the major lineaments are high. In the NNE-SSW fractures of Set 1, well yields at distances of 0-60 m from the major fractures are high but much lower than the highest well yields in the shear fractures at about 90-120 m. The relationship between well yield and distance to fracture lineaments in the three sets of fractures indicates that both of the shear fractures are hydrotectonically more significant than the tensile fractures. Of the shear fractures the N-S trending Set 2 lineaments are relatively the most important in terms of groundwater potential. The data summarized in a conceptual hydrotectonic model can be used as a working reference in selecting potential sites for future groundwater exploration in the region. Although drilling sites can be designed within the optimum distances, for example, 90 m distance, along the N-S trending fractures, supplementary detailed geophysical investigations should be carried out prior to drilling. The lineament analysis using GIS thus provides a means for scaling down target areas and design cost-effective and successful groundwater exploration programmes.

  9. Correlation of Geoelectric Data with Aquifer Parameters to Delineate the Groundwater Potential of Hard rock Terrain in Central Uganda

    Science.gov (United States)

    Batte, A. G.; Barifaijo, E.; Kiberu, J. M.; Kawule, W.; Muwanga, A.; Owor, M.; Kisekulo, J.

    2010-12-01

    Knowledge of aquifer parameters is essential for management of groundwater resources. Conventionally, these parameters are estimated through pumping tests carried out on water wells. This paper presents a study that was conducted in three villages (Tumba, Kabazi, and Ndaiga) of Nakasongola District, central Uganda to investigate the hydrogeological characteristics of the basement aquifers. Our objective was to correlate surface resistivity data with aquifer properties in order to reveal the groundwater potential in the district. Existing electrical resistivity and borehole data from 20 villages in Nakasongola District were used to correlate the aquifer apparent resistivity ( ρ e) with its hydraulic conductivity ( K e), and aquifer transverse resistance (TR) with its transmissivity ( T e). K e was found to be related to ρ e by; {{Log }}(K_{{e}} ) = - 0.002ρ_{{e}} + 2.692 . Similarly, TR was found to be related to T by; {{TR}} = - 0.07T_{{e}} + 2260 . Using these expressions, aquifer parameters ( T c and K c) were extrapolated from measurements obtained from surface resistivity surveys. Our results show very low resistivities for the presumed water-bearing aquifer zones, possibly because of deteriorating quality of the groundwater and their packing and grain size. Drilling at the preferred VES spots was conducted before the pumping tests to reveal the aquifer characteristics. Aquifer parameters ( T o and K o) as obtained from pumping tests gave values (29,424.7 m2/day, 374.3 m/day), (9,801.1 m2/day, 437.0 m/day), (31,852.4 m2/day, 392.9 m/day). The estimated aquifer parameter ( T c and K c) when extrapolated from surface geoelectrical data gave (7,142.9 m2/day, 381.9 m/day), (28,200.0 m2/day, 463.4 m/day), (19,428.6 m2/day, 459.2 m/day) for Tumba, Kabazi, and Ndaiga villages, respectively. Interestingly, the similarity between the K c and K o pairs was not significantly different. We observed no significant relationships between the T c and T o pairs. The root

  10. Source-inherited compositional diversity in granite batholiths: The geochemical message of Late Paleozoic intrusive magmatism in central Calabria (southern Italy)

    Science.gov (United States)

    Fiannacca, Patrizia; Cirrincione, Rosolino; Bonanno, Fiorenza; Carciotto, Manuele Mario

    2015-11-01

    The Serre Batholith, in central Calabria, is a Late Paleozoic granitoid complex that makes up the middle portion, ca. 13 km thick, of a continuous and nearly complete section of the continental crust. The batholith displays a large compositional variety, with granitoid rocks ranging with continuity from quartz diorite to syenogranite, a distinct group of leucotonalites also occur. The granitoids are on the whole magnesian and calcic to calc-alkalic, with only some of the more evolved rocks showing a ferroan calc-alkalic to alkali-calcic composition. Quartz diorites and tonalites are metaluminous to weakly peraluminous, while granodiorites and granites are weakly to strongly peraluminous, with two-mica porphyritic types being the only population with a genuine strongly peraluminous character. Fe*-number, MALI and ASI features highlight a strong affinity of the Serre Batholith rocks with Cordilleran granitoids, inherited from the compositions of the source rocks rather than reflecting the real tectonic environment of the magmas. Major trace element and existing Sr-Nd data are consistent with an origin of the Serre Batholith from the assembling of several batches of magmas with specific original compositions derived by fluid-absent melting of different crustal sources. Quartz diorites and tonalites originated from a metabasaltic magma source, whereas metagraywackes with various mafic and pelitic contents appear the most likely sources of weakly peraluminous granodiorites and strongly peraluminous granodiorites and granites. Biotite ± amphibole granodiorites could also have been derived from mafic-intermediate metaigneous sources. Two-mica porphyritic leucogranites are the only rock types representing pure crustal melts, resulting from melting of mafic pelitic sources. The other granitoid compositions are too silica-poor and MgO + FeOt rich to represent pure melts, so they need to include other components, such as solid restitic/peritectic material entrained from the

  11. Relationship between changes in the velocity of longitudinal seismic waves and certain geological-engineering parameters of rock in the Central Kyzylkum

    Energy Technology Data Exchange (ETDEWEB)

    Tallyabaev, R.A.

    1979-01-01

    An examination is made of the interconnection between the longitudinal velocity of seismic waves and certain physico-mechanical properties of rock. Tables are presented for calculated values for seismic wave velocities in relation to various types of rock. The relationship between the longitudinal velocity of seismic waves of sandy-gravel-clay rock and the porosity coefficient was found to be inversely proportional. 4 references, 1 figure.

  12. LA-ICP-MS U-Pb apatite dating of Lower Cretaceous rocks from teschenite-picrite association in the Silesian Unit (southern Poland

    Directory of Open Access Journals (Sweden)

    Szopa Krzysztof

    2014-08-01

    Full Text Available The main products of volcanic activity in the teschenite-picrite association (TPA are shallow, sub-volcanic intrusions, which predominate over extrusive volcanic rocks. They comprise a wide range of intrusive rocks which fall into two main groups: alkaline (teschenite, picrite, syenite, lamprophyre and subalkaline (dolerite. Previous 40Ar/39Ar and 40K/40Ar dating of these rocks in the Polish Outer Western Carpathians, performed on kaersutite, sub-silicic diopside, phlogopite/biotite as well as on whole rock samples has yielded Early Cretaceous ages. Fluorapatite crystals were dated by the U-Pb LA-ICP-MS method to obtain the age of selected magmatic rocks (teschenite, lamprophyre from the Cieszyn igneous province. Apatite-bearing samples from Boguszowice, Puńców and Lipowa yield U-Pb ages of 103± 20 Ma, 119.6 ± 3.2 Ma and 126.5 ± 8.8 Ma, respectively. The weighted average age for all three samples is 117.8 ± 7.3 Ma (MSWD = 2.7. The considerably smaller dispersion in the apatite ages compared to the published amphibole and biotite ages is probably caused by the U-Pb system in apatite being less susceptible to the effects of hydrothermal alternation than the 40Ar/39Ar or 40K/40Ar system in amphibole and/or biotite. Available data suggest that volcanic activity in the Silesian Basin took place from 128 to 103 Ma with the the main magmatic phase constrained to 128-120 Ma.

  13. Urban airborne matter in central and southern Chile: Effects of meteorological conditions on fine and coarse particulate matter

    Science.gov (United States)

    Yáñez, Marco A.; Baettig, Ricardo; Cornejo, Jorge; Zamudio, Francisco; Guajardo, Jorge; Fica, Rodrigo

    2017-07-01

    Air pollution is one of the major global environmental problems affecting human health and life quality. Many cities of Chile are heavily polluted with PM2.5 and PM10, mainly in the cold season, and there is little understanding of how the variation in particle matter differs between cities and how this is affected by the meteorological conditions. The objective of this study was to assess the effect of meteorological variables on respirable particulate matter (PM) of the main cities in the central-south valley of Chile during the cold season (May to August) between 2014 and 2016. We used hourly PM2.5 and PMcoarse (PM10- PM2.5) information along with wind speed, temperature and relative humidity, and other variables derived from meteorological parameters. Generalized additive models (GAMs) were fitted for each of the eight cities selected, covering a latitudinal range of 929 km, from Santiago to Osorno. Great variation in PM was found between cities during the cold months, and that variation exhibited a marked latitudinal pattern. Overall, the more northerly cities tended to be less polluted in PM2.5 and more polluted in PMcoarse than the more southerly cities, and vice versa. The results show that other derived variables from meteorology were better related with PM than the use of traditional daily means. The main variables selected with regard to PM2.5 content were mean wind speed and minimum temperature (negative relationship). Otherwise, the main variables selected with regard to PMcoarse content were mean wind speed (negative), and the daily range in temperature (positive). Variables derived from relative humidity contributed differently to the models, having a higher effect on PMcoarse than PM2.5, and exhibiting both negative and positive effects. For the different cities the deviance explained by the GAMs ranged from 37.6 to 79.1% for PM2.5 and from 18.5 to 63.7% for PMcoarse. The percentage of deviance explained by the models for PM2.5 exhibited a

  14. Reconnaissance of the Pere Marquette River, a cold water river in the central part of Michigan's Southern Peninsula

    Science.gov (United States)

    Hendrickson, G.E.; Doonan, C.J.

    1971-01-01

    The cold-water streams of the northern states provide unique recreational values to the American people (wilderness or semi-wilderness atmosphere, fast-water canoeing, and trout fishing) but the expanding recreational needs must be balanced against the growing demand of water for public and industrial supplies, for irrigation, and for the dilution of sewage and other wastes. In order to make intelligent decisions regarding use and management of the water resource for recreation and other demands, an analysis of the hydrologic factors related to recreational values is essential.The Pere Marquette, an outstanding river for brown and steelhead trout fishing, is also a popular canoe trail. Larger boats, some equipped with motors, are common in the lower reaches where the river is wide and deep. Cabins are abundant on the river near Baldwin but are relatively sparse elsewhere. The broad swampy floodplain that borders most of the river between Walhalla and Ludington apparently offers few favorable cabin sites.The Pere Marquette is located in the west-central part of the Southern Peninsula of Michigan, and flows westward from the headwaters near Chase in Lake County to the mouth at Ludington, in Mason County. The river is south of, and roughly parallel to, U.S. Highway 10 from Chase to Ludington. Access to the river is by roads leading south from U.S. 10 at Nirvana, Idlewild, Baldwin, Branch, Walhalla, Scottville, and many intermediate points.The recreational value of the river depends on the streamflow characteristics, quality of water, and character of stream channel and bed and banks. The purpose of this report is to describe these characteristics and show how they relate to recreational USGS.Most of the information presented here was obtained from a field reconnaissance in July and August, 1966, and from basic records of the U.S. Geological Survey's Water Resources Division. The area of field study is limited to the channel, bed, and banks of the Middle Branch and

  15. Reconnaissance of the Pigeon River, a cold-water river in the north-central part of Michigan's southern peninsula

    Science.gov (United States)

    Hendrickson, G.E.; Doonan, C.J.

    1970-01-01

    The cold-water streams of the northern states provide unique recreational values to the American people (wilderness or semi-wilderness atmosphere, fast-water canoeing, and trout fishing), but the expanding recreational needs must be balanced against the growing demand of water for public and industrial supplies, for irrigation, and for the dilution of sewage and other wastes. In order to make intelligent decisions regarding use and management of the water resource for recreation and other demands, an analysis of the hydrologic factors related to recreational values is essential.The Pigeon River is one of Michigan's outstanding trout streams and is the favorite of a large number of anglers who return year after year. Camping is also popular and is usually, but not always, associated with fishing. Boating is very rare on the Pigeon because of numerous portages around log jams. Cabin-living and resorting are relatively minor on this river as yet, but much of the private river front may be developed in future years.The Pigeon is located in the north-central part of the southern peninsula of Michigan (see index map). Headwaters are a few miles northeast of Gaylord, and the mouth is at Mullet Lake, a few miles northeast of Indian River. Interstate Highway 75 roughly parallels the river about 5 to 10 miles to the west. Exits from this highway at Gaylord, Vanderbilt, Wolverine, and Indian River, provide easy access to the Pigeon.The recreational value of the river depends on the streamflow characteristics, quality of water, and character of stream channel, and bed and banks. The purpose of this atlas is to describe these characteristics, and to show how they relate to recreational uses.Most of the information presented here was obtained from a field reconnaissance in June, 1966, and from basic records of the U.S. Geological Survey's Water Resources Division. The area of field study is limited to the channel, bed, and banks of the main stem of the Pigeon from source to

  16. Reconnaissance of the Black River, a cold-water river in the north-central part of Michigan's southern peninsula

    Science.gov (United States)

    Hendrickson, G.E.; Doonan, C.J.

    1971-01-01

    The cold-water streams of the northern states provide unique recreational values to the American people (wilderness or semi-wilderness atmosphere, fast-water canoeing, trout fishing) but the expanding recreational needs must be balanced against the growing demand of water for public and industrial supplies, for irrigation, and for the dilution of sewage and other wastes. In order to make intelligent decisions regarding use and management of the water resource for recreation and other demands, an analysis of the hydrologic factors related to recreational values is essential.The Black River north of Johannesburg in Otsego County has been rated by many fisherman as the number one brook-trout stream in the north-central part of the southern peninsula of Michigan. Headwaters are a few miles north of Johannesburg, and the Black flows northward to join the Cheboygan river a few miles south of Cheyboygan. Only the part of the Black upstream from the impoundment at Tower is included in this report.The headwaters of the Black can be reached by driving east and north from Gaylord, or east from Vanderbilt. The lower reaches included in this study can be reached from Tower or Onaway.The recreational value of a river depends on the characteristics of streamflow, water-quality, and its bed and banks. The purpose of this atlas is to describe these characteristics and to show how they relate to recreational uses.Some of the information presented here was derived from basic records of the U.S. Geological Survey's Water-Resources Division. Additional information was obtained in field reconnaissance surveys in 1966 and 1968. The study was made in cooperation with the Michigan Geological Survey, Gerald E. Eddy, Chief. Advice and assistance were also obtained from other sections of the Michigan Conservation Department.Sheet 1 of this atlas presents information on streamflow characteristics and water quality. Sheet 2 describes the physical character of the stream channel, bed and banks

  17. Reconnaissance of the Sturgeon River, a cold-water river in the north-central part of Michigan's southern peninsula

    Science.gov (United States)

    Hendrickson, G.E.; Doonan, C.J.

    1971-01-01

    The cold-water streams of the northern states provide unique recreational values to the American people (wilderness or semi-wilderness atmosphere, fast-water canoeing, trout fishing), but the expanding recreational needs must be balanced against the growing demand of water for public and industrial supplies, for irrigation, and for the dilution of sewage and other wastes. In order to make intelligent decisions regarding use and management of the water resources for recreation and other demands, analysis of the hydrologic factors related to recreational values is essential.The Sturgeon River north of Gaylord, one of the best brown trout streams in Michigan, is located in the north-central part of the southern peninsula of Michigan with headwaters just north of Gaylord. The Sturgeon flows northward, generally paralleling Interstate Highway 75. The West Branch of the Sturgeon, which joins the main stem at Wolverine, was not included in this study. Exits from Interstate 75 at Gaylord, Vanderbilt, Wolverine, and Indian River provide easy access to the Sturgeon. The recreational value of a river depends on the hydrologic characteristics of the river-the streamflow, water quality, and character of bed and banks. The purpose of this atlas is to describe these characteristics and to show how they relate to recreational uses. Much of the information presented here was derived from basic records of the U.S. Geological Survey's Water Resources Division. Additional information was obtained in a reconnaissance survey in May and June, 1966. The area of field study is limited to the channel, bed, and banks of the main stem from source to mouth. The study was made in cooperation with the Michigan Geological Survey, Gerald E. Eddy, Chief. Advice and assistance were also obtained from other sections of the Michigan Conservation Department. Sheet 1 of this atlas presents information on streamflow characteristics and water quality. Sheet 2 describes the physical characteristics of the

  18. 100 kyr fluvial cut-and-fill terrace cycles since the Middle Pleistocene in the southern Central Andes, NW Argentina

    Science.gov (United States)

    Tofelde, Stefanie; Schildgen, Taylor F.; Savi, Sara; Pingel, Heiko; Wickert, Andrew D.; Bookhagen, Bodo; Wittmann, Hella; Alonso, Ricardo N.; Cottle, John; Strecker, Manfred R.

    2017-09-01

    Fluvial fill terraces in intermontane basins are valuable geomorphic archives that can record tectonically and/or climatically driven changes of the Earth-surface process system. However, often the preservation of fill terrace sequences is incomplete and/or they may form far away from their source areas, complicating the identification of causal links between forcing mechanisms and landscape response, especially over multi-millennial timescales. The intermontane Toro Basin in the southern Central Andes exhibits at least five generations of fluvial terraces that have been sculpted into several-hundred-meter-thick Quaternary valley-fill conglomerates. New surface-exposure dating using nine cosmogenic 10Be depth profiles reveals the successive abandonment of these terraces with a 100 kyr cyclicity between 75 ± 7 and 487 ± 34 ka. Depositional ages of the conglomerates, determined by four 26Al/10Be burial samples and U-Pb zircon ages of three intercalated volcanic ash beds, range from 18 ± 141 to 936 ± 170 ka, indicating that there were multiple cut-and-fill episodes. Although the initial onset of aggradation at ∼1 Ma and the overall net incision since ca. 500 ka can be linked to tectonic processes at the narrow basin outlet, the superimposed 100 kyr cycles of aggradation and incision are best explained by eccentricity-driven climate change. Within these cycles, the onset of river incision can be correlated with global cold periods and enhanced humid phases recorded in paleoclimate archives on the adjacent Bolivian Altiplano, whereas deposition occurred mainly during more arid phases on the Altiplano and global interglacial periods. We suggest that enhanced runoff during global cold phases - due to increased regional precipitation rates, reduced evapotranspiration, or both - resulted in an increased sediment-transport capacity in the Toro Basin, which outweighed any possible increases in upstream sediment supply and thus triggered incision. Compared with two

  19. Assessing the Viability of Sub-Surface Drip Irrigation for Resource-Efficient Alfalfa Production in Central and Southern California

    Directory of Open Access Journals (Sweden)

    Daniele Zaccaria

    2017-10-01

    Full Text Available In California, alfalfa is grown on a large area ranging between 325,000 and 410,000 hectares and ranks among the thirstiest crops. While the hay production industry is often scrutinized for the large usage of the state’s agricultural water, alfalfa is a crucial feed-supplier for the livestock and dairy sectors, which rank among the most profitable commodity groups in the state. Sub-surface drip irrigation (SDI, although only practiced on approximately 2% of the alfalfa production area in California, is claimed to have the potential to significantly increase hay yield (HY and water productivity (WP compared with surface irrigation (SI. In 2014–2016 we interviewed a number of growers pioneering SDI for alfalfa production in Central and Southern California who reported that yield improvements in the order of 10–30% and water saving of about 20–30% are achievable in SDI-irrigated fields compared with SI, according to their records and perceptions collected over few years of experience. Results from our research on SDI at the University of California, Davis, revealed significantly smaller yield gain (~5% and a slight increase of water use (~2–3% that are similar to findings from earlier research studies. We found that most of the interviewed alfalfa producers are generally satisfied with their SDI systems, yet face some challenges that call for additional research and educational efforts. Key limitations of SDI include high investment costs, use of energy to pressurize water, the need for more advanced irrigation management skills, and better understanding of soil-water dynamics by farm personnel. SDI-irrigated fields also need accurate water monitoring and control, attentive prevention and repair of rodent damages, and careful salinity management in the root zone. In this paper we attempt to evaluate the viability of the SDI technology for alfalfa production on the basis of preliminary results of our research and extension activities, with

  20. Temporal and spatial patterns in wind stress and wind stress curl over the central Southern California Bight

    Science.gov (United States)

    Noble, Marlene A.; Rosenberger, Kurt J.; Rosenfeld, Leslie K.; Robertson, George L.

    2012-01-01

    In 2001, the U.S. Geological Survey, together with several other federal and municipal agencies, began a series of field programs to determine along and cross-shelf transport patterns over the continental shelves in the central Southern California Bight. As a part of these programs, moorings that monitor winds were deployed off the Palos Verdes peninsula and within San Pedro Bay for six 3–4 month summer and winter periods between 2001 and 2008. In addition, nearly continuous records of winds for this 7-year period were obtained from a terrestrial site at the coast and from a basin site offshore of the long-term coastal site. The mean annual winds are downcoast at all sites. The alongshelf components of wind stress, which are the largest part of the low-frequency wind stress fields, are well correlated between basin, shelf and coastal sites. On average, the amplitude of alongshelf fluctuations in wind stress are 3–4 times larger over the offshore basin, compared to the coastal site, irrespective of whether the fluctuations represent the total, or just the correlated portion of the wind stress field. The curl in the large-scale wind stress tends to be positive, especially in the winter season when the mean wind stress is downcoast and larger at the offshore basin site than at the beach. However, since the fluctuation in wind stress amplitudes are usually larger than the mean, periods of weak negative curl do occur, especially in the summer season when the largest normalized differences in the amplitude of wind stress fluctuations are found in the nearshore region of the coastal ocean. Even though the low-frequency wind stress field is well-correlated over the continental shelf and offshore basins, out to distances of 35 km or more from the coast, winds even 10 km inshore of the beach do not represent the coastal wind field, at least in the summer months. The seasonal changes in the spatial structures in wind stress amplitudes suggest that an assessment of the

  1. Age and petrogenesis of Na-rich felsic rocks in western Iran: Evidence for closure of the southern branch of the Neo-Tethys in the Late Cretaceous

    Science.gov (United States)

    Nouri, Fatemeh; Azizi, Hossein; Golonka, Jan; Asahara, Yoshihiro; Orihashi, Yuji; Yamamoto, Koshi; Tsuboi, Motohiro; Anma, Ryo

    2016-03-01

    Intermediate to felsic volcanic and granitic rocks with high Na2O concentrations (5.2-9.1 wt.%) are widely distributed in the Harsin area along the Zagros thrust zone in western Iran. Most of these rocks are classified as low-potassium tholeiite, display affinity with oceanic plagiogranite and contain somewhat high Na content and low concentrations of K2O, Al2O3, Rb, Sr and Ca. Thus, we prefer to apply the term Na-rich felsic rocks to this complex. U-Pb dating yielded ages of 94.6 ± 2.7 Ma (2σ) from baddeleyite and 95.0 ± 2.4 Ma (2σ) from zircon grains, indicating that the complex crystallized in the Late Cretaceous. Based on the mineral compositions, the crystallization occurred at low pressures (mostly Neo-Tethys. This event was the first stage of the Zagros collision, which was followed by collision of the Arabian and Iranian plates during the Eocene through Neogene.

  2. Trace Element Accumulation and Tissue Distribution in the Purpleback Flying Squid Sthenoteuthis oualaniensis from the Central and Southern South China Sea.

    Science.gov (United States)

    Wu, Yan Yan; Shen, Yu; Huang, Hui; Yang, Xian Qing; Zhao, Yong Qiang; Cen, Jian Wei; Qi, Bo

    2017-01-01

    Sthenoteuthis oualaniensis is a species of cephalopod that is becoming economically important in the South China Sea. As, Cd, Cr, Cu, Hg, Pb, and Zn concentrations were determined in the mantle, arms, and digestive gland of S. oualaniensis from 31 oceanographic survey stations in the central and southern South China Sea. Intraspecific and interspecific comparisons with previous studies were made. Mean concentrations of trace elements analyzed in arms and mantle were in the following orders: Zn > Cu > Cd > Cr > As > Hg. In digestive gland, the concentrations of Cd and Cu exceed that of Zn. All the Pb concentrations were under the detected limit.

  3. Renewable energy resource and technology assessment: Southern Tier Central Region, New York, New York. Renewable Energy Resource Inventory; renewable energy technology handbook; technology assessment workbook

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    The Renewable Energy Resource Inventory contains regional maps that record the location of renewable energy resources such as insolation, wind, biomass, and hydropower in the Southern Tier Central Region of New York State. It contains an outline of a process by which communities can prepare local renewable energy resource inventories using maps and overlays. The process starts with the mapping of the resources at a regional scale and telescopes to an analysis of resources at a site-specific scale. The resource inventory presents a site analysis of Sullivan Street Industrial Park, Elmira, New York.

  4. Petrology and ⁴⁰Ar/3⁹Ar-chronology of metavolcanic rocks from the Northern Phyllite Zone (Southern Hunsrück and Taunus Mountains, Germany): insights into a late Variscan ductile shear zone.

    Science.gov (United States)

    Fladt, Matthias; Soder, Christian; Schwarz, Winfried; Trieloff, Mario

    2017-04-01

    The Northern Phyllite Zone (NPZ) is a low-grade mylonitic shear zone between the high-grade rocks of the Mid-German Crystalline Zone and the very low-grade rocks of the Rhenohercynian Zone of the Variscan orogen. The NPZ comprises low-grade metasedimentary and metavolcanic rocks. Basaltic, intermediate and rhyolitic metavolcanics from the Soonwald and the Southern Taunus Mountains show the following paragenesis: actinolite + chlorite + epidote + albite + phengite + titanite + quartz ± calcite ± stilpnomelane ± pumpellyite ± aegirine-augite; blue amphibole (winchite) + chlorite + phengite + stilpnomelane + albite + titanite + quartz + magnetite ± epidote ± hematite; quartz + albite + K-feldspar + phengite + chlorite + titanite ± stilpnomelane ± ilmenite ± magnetite ± hematite. Occasionally, relict magmatic phases are present. The foliation strikes SW-NE and dips 60-70° to the NW. Stretching lineations are subhorizontal. P-T-estimations were done on the basis of equilibrium assemblage modelling yielding peak metamorphic conditions of 300-350 °C and 6-6.5 kbar. Thus, burial depths of 20-22 km and a low geothermal gradient of 15-16 °C/km are inferred. ⁴⁰Ar/3⁹Ar-dating of stepwise heated phengite separates (100-200 µm) results in plateau ages of ˜320 Ma. Two of the examined separates show argon diffusive loss ⁴⁰Ar/3⁹Ar-age spectra, which yield a period of argon loss between 145 and 130 Ma. Diffusive argon loss is possibly related to widespread Jurassic-Cretaceous hydrothermal activity in SW Germany. We interpret the Northern Phyllite Zone as a sinistral shear zone documenting prolonged oblique convergence following the peak of the Variscan orogeny between 340-330 Ma until 320 Ma.

  5. Validation of digital elevation models (DEMs) and comparison of geomorphic metrics on the southern Central Andean Plateau

    Science.gov (United States)

    Purinton, Benjamin; Bookhagen, Bodo

    2017-04-01

    In this study, we validate and compare elevation accuracy and geomorphic metrics of satellite-derived digital elevation models (DEMs) on the southern Central Andean Plateau. The plateau has an average elevation of 3.7 km and is characterized by diverse topography and relief, lack of vegetation, and clear skies that create ideal conditions for remote sensing. At 30 m resolution, SRTM-C, ASTER GDEM2, stacked ASTER L1A stereopair DEM, ALOS World 3D, and TanDEM-X have been analyzed. The higher-resolution datasets include 12 m TanDEM-X, 10 m single-CoSSC TerraSAR-X/TanDEM-X DEMs, and 5 m ALOS World 3D. These DEMs are state of the art for optical (ASTER and ALOS) and radar (SRTM-C and TanDEM-X) spaceborne sensors. We assessed vertical accuracy by comparing standard deviations of the DEM elevation versus 307 509 differential GPS measurements across 4000 m of elevation. For the 30 m DEMs, the ASTER datasets had the highest vertical standard deviation at > 6.5 m, whereas the SRTM-C, ALOS World 3D, and TanDEM-X were all < 3.5 m. Higher-resolution DEMs generally had lower uncertainty, with both the 12 m TanDEM-X and 5 m ALOS World 3D having < 2 m vertical standard deviation. Analysis of vertical uncertainty with respect to terrain elevation, slope, and aspect revealed the low uncertainty across these attributes for SRTM-C (30 m), TanDEM-X (12-30 m), and ALOS World 3D (5-30 m). Single-CoSSC TerraSAR-X/TanDEM-X 10 m DEMs and the 30 m ASTER GDEM2 displayed slight aspect biases, which were removed in their stacked counterparts (TanDEM-X and ASTER Stack). Based on low vertical standard deviations and visual inspection alongside optical satellite data, we selected the 30 m SRTM-C, 12-30 m TanDEM-X, 10 m single-CoSSC TerraSAR-X/TanDEM-X, and 5 m ALOS World 3D for geomorphic metric comparison in a 66 km2 catchment with a distinct river knickpoint. Consistent m/n values were found using chi plot channel profile analysis, regardless of DEM type and spatial resolution. Slope, curvature

  6. Spatial distribution of rock glaciers in the semi-arid Andes of Argentina

    Science.gov (United States)

    Blöthe, Jan Henrik; Halla, Christian; Schrott, Lothar; Götz, Joachim; Trombotto, Dario

    2016-04-01

    Active rock glaciers are indicators for permafrost in periglacial environments of high mountain areas. Within the permafrost body and the seasonally frozen active layer, these rock glaciers potentially store large amounts of water. Especially in semiarid mountain belts, such as the central Andes of Argentina, rock glaciers attain several kilometres in length, covering surface areas of >106 m2. Here, rock glaciers even outrange ice glaciers in cumulative area and absolute number, indicating they might constitute a large water reservoir in this semiarid part of the Andes. Despite their potential hydrological importance, our knowledge about the rock glaciers' spatial distribution, subsurface composition and absolute ice content is still very limited. Our study addresses this shortcoming and aims at assessing the hydrological significance of rock glacier permafrost in the semi-arid Andes of Argentina by combining local geophysical investigations with regional remote sensing analysis. Our research focuses on the central Andes between 30°S and 33°S, where we have compiled an inventory that comprises more than 1200 rock glaciers, as well as 154 clear-ice and debris-covered glaciers. Two field sites that bracket this regional study area towards their northern and southern edge have been selected for local geophysical investigations. At these locations, earlier studies detected the presence of rock glacier permafrost by thermal monitoring and geophysical prospection. Preliminary results of the regional spatial distribution indicate that the spatial density of rock glaciers increases towards the south, concomitant with a twofold increase in mean annual precipitation. Rock glacier density peaks in the area of the Aconcagua massif, while precipitation is further increasing towards the south. Simultaneously, the lower altitudinal limit of intact rock glaciers slightly decreases, with the lowest rock glacier toe positions in the northern study area located at ~3800 m a. s. l

  7. Thermal effects of the Santa Eulália Plutonic Complex (southern Portugal on the meta-igneous and metasedimentary host rocks

    Directory of Open Access Journals (Sweden)

    Cruz, C.

    2014-12-01

    Full Text Available The Santa Eulália Plutonic Complex (SEPC is a late-Variscan granitic body located in the northern part of the Ossa Morena Zone, a inner zone of the Variscan Iberian Massif. The SEPC host rocks are composed of meta-igneous and metasedimentary units, from Upper Proterozoic to Paleozoic ages, with a NW-SE structure, cross-cut by the SEPC. The SEPC host rocks, with low grade metamorphism show well preserved primary sedimentary or igneous mineralogical, textural and structural features. The thermal effect induced by the SEPC is restricted to the roof pendants. At N and NE of the SEPC, textures and paragenesis resulting from thermal metamorphism, are not related to the SEPC intrusion but to a previous magmatism, controlled by the NW-SE regional anisotropies. The restriction of the thermal effects to the pluton roof may be caused by a combination of several interrelated factors: higher volume of granitic mass, thermal effect by advection of fluids and longer period of prevalence of high thermal conditions. The geochemical study of SEPC host rocks shows the heterogeneous character and diversity of metasedimentary, igneous and meta-igneous rocks. The whole rock geochemical data indicate that all the metasedimentary lithologies derived from an upper continental crustal source and the igneous and meta-igneous rocks show no evidence of metasomatic effects by the SEPC emplacement.El Complejo Plutónico de Santa Eulalia (CPSE es un cuerpo granítico tardi-Varisco situado en la parte norte de la Zona de Ossa Morena, en la zona interior del Macizo Ibérico Varisco. Las rocas encajantes del CPSE están compuestas por unidades meta-ígneas y metasedimentarias, de edades que van desde el Proterozoico Superior hasta el Paleozoico, con una estructura de dirección NW-SE, cortada por el CPSE. Las rocas encanjantes del CPSE, con metamorfismo de bajo grado conservan estructuras, mineralogía y textura primarias. El efecto térmicoinducido por el CPSE se limita a los

  8. Chaparral in southern and central coastal California in the mid-1990s: area, ownership, condition, and change.

    Science.gov (United States)

    Jeremy S. Fried; Charles L. Bolsinger; Debby. Beardsley

    2004-01-01

    This report summarizes an inventory of chaparral-dominated lands in southern California conducted during the mid-1990s and provides a review of contemporary literature on the ecological dynamics of chaparral vegetation with emphases on stand development, species composition, and the role of fire. Detailed tables provide estimates of chaparral area by owner, type, size...

  9. 76 FR 41788 - Southern Star Central Gas Pipeline, Inc.; Notice of Intent To Prepare an Environmental Assessment...

    Science.gov (United States)

    2011-07-15

    ... as the Misener Sandstone. Southern Star would also remove existing tank battery facilities dedicated... appendix 1.\\1\\ \\1\\ The appendices referenced in this notice are not being printed in the Federal Register... production well to an observation well and to remove tank battery facilities. Following construction, about 0...

  10. Disturbance from southern pine beetle, suppression, and wildfire affects vegetation composition in central Louisiana: a case study

    Science.gov (United States)

    T.W. Coleman; Alton Martin; J.R. Meeker

    2010-01-01

    We assessed plant composition and forest succession following tree mortality from infestation of southern pine beetle (Dendroctonus frontalis), associated suppression, and wildfire in two forest types, pine (Pinus spp.) with mixed hardwood and longleaf pine (P. palustris). In this case study, vegetation was...

  11. Estimated Altitude of the Consolidated Rock Surface Underlying Quaternary Sediments of the Wood River Valley aquifer system, South-Central Idaho

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is the estimated altitude of the consolidated rock surface underlying Quaternary sediment of the Wood River Valley aquifer system. This surface is...

  12. A quasi-linear structure of the southern margin of Eurasia prior to the India-Asia collision: First paleomagnetic constraints from Upper Cretaceous volcanic rocks near the western syntaxis of Tibet

    Science.gov (United States)

    Yi, Zhiyu; Huang, Baochun; Yang, Liekun; Tang, Xiangde; Yan, Yonggang; Qiao, Qingqing; Zhao, Jie; Chen, Liwei

    2015-07-01

    We report the first combined geochronologic and paleomagnetic study of volcanic rocks from the Shiquanhe and Yare Basins at the westernmost Lhasa Terrane, which aims to provide an accurate constraint on the shape and paleoposition of the southern margin of Asia prior to the India-Asia collision. Three new 40Ar/39Ar ages of 92.5 ± 2.9 Ma, 92.4 ± 0.9 Ma, and 79.6 ± 0.7 Ma determined by fresh matrix or feldspar from lava flows suggest a Late Cretaceous age for the investigated units. Characteristic remanent magnetizations have been successfully isolated from 38 sites which pass positive fold and/or reversal, conglomerate tests and are hence interpreted as primary in origin. The two paleopoles obtained from Yare and Shiquanhe yield consistent paleolatitudes of 13.6°N ± 9.6°N and 14.2°N ± 2.7°N, respectively (for a reference site of 31.5°N, 80°E), indicating that the southern margin of Asia near the western syntaxis was located far south during the Late Cretaceous time. A reconstruction of the Lhasa Terrane in the frame of Eurasia with paleomagnetic data obtained from its western and eastern parts indicates that the southern margin of Eurasia probably had a quasi-linear orientation prior to the collision formerly trending approximately 315°E. This is compatible with the shape of the Neo-Tethys slab observed from seismic tomographic studies. Our findings provide a solid basis for evaluating Cenozoic crustal shortening in the Asian interior and the size of Greater India near the western syntaxis.

  13. Soil differentiation in two toposequences developed from basaltic rocks in North-Central region of the Paraná State, Brazil

    Directory of Open Access Journals (Sweden)

    Marcos Aparecido Gonçalves

    2013-12-01

    Full Text Available In regions where there were basaltic rocks formation due to magmatic flows, variation in particle sizes and rock composition determine characteristic reliefs influencing chemical and physical attributes. The aim of the article was to characterize two different toposequences over basaltic rock basis, in order to identify the influence of their variation in soil formation, morphological properties and their distribution along the slope. The study was carried out in the Third Plateau of Parana State, Brazil, at Serra Geral geological formation, There were chosen two toposequences in equidistant 2000m parallel transects in southwest-northeast direction with different relief and rock composition and features. It was named undulated relief slope (VRO and gently undulated relief slope (VSO in which there were carried out profile morphological description with soil classes identifying, chemical analysis and clay mineralogical analysis. The results permitted to conclude that the internal dynamic and the magmatic segregation process were responsible for relief shapes and rock types formed with significant variation in soil types according variation in composition in the same rock, Both relief shapes and basalt differentiation had strong influence in soil evolution level and soil type distribution along the slopes with distinct B horizons, Nitic B and Latosolic B

  14. Timing and processes for exhumation of HP/LT rocks of the southern Brooks Range (AK): Insight from combined geochemistry and 40Ar/39Ar thermochronology of white mica

    Science.gov (United States)

    O'Brien, T.; Miller, E. L.; Grove, M. J.; Hayden, L. A.

    2015-12-01

    The obduction of an island arc onto the Arctic Alaska continental margin in the Jura-Cretaceous led to southward subduction of continental crust and high-pressure/low-temperature (HP/LT) epidote-blueschist facies metamorphism in the southern Brooks Range (BR). A regionally developed greenschist facies normal-sense shear zone system along the southern margin of the BR suggests that extensional faulting had an influential role in the exhumation of the metamorphic core. To better constrain the exhumation history of the metamorphic core of the BR, samples were collected from a N-S transect through the metamorphic core of the orogen. Electron microprobe (EMP) analyses of white micas reveal that they are composed of phengite (Si > 3.0 pfu) or a combination of phengite + paragonite. Si-content of phengites reveal a southward increase in Si from 3.1 to 3.4 pfu (corresponding to an increase in pressure). Si-contents in higher-P phengites are scattered, reflecting subsequent muscovite growth. The Si trend is matched by a southward increase in the 40Ar/39Ar total gas ages of white micas. Phengite from the north are characterized by younger ages (~115 Ma) and flatter 40Ar/39Ar spectra. Farther south, phengites and paragonites yield older 40Ar/39Ar ages. These samples yield convex, staircase 40Ar/39Ar spectra that initiate ~115-120 Ma and flatten-out ~130-138 Ma. Modeling using MacArgon proposes that an initial cooling of HP/LT metamorphism occurred ~130-138 Ma, recorded in the high-Si phengites and paragonites. Following initial cooling, modeling suggests HP/LT rocks stalled in the greenschist facies field before subsequent exhumation, resulting in the staircase 40Ar/39Ar spectra. Flatter 40Ar/39Ar spectra recorded by the northern samples and modeling of 40Ar/39Ar results from the southern samples suggest that these rocks from metamorphic core of the BR were exhumed to temperatures < 300°C by ~115 Ma.

  15. Structure of the Cocos subduction zone in central and southern Mexico from three-dimensional body-wave attenuation and travel time tomography

    Science.gov (United States)

    Chen, T.; Clayton, R. W.

    2011-12-01

    The 3D P- and S-wave attenuation and velocity structure of the Cocos subduction zone in Mexico is imaged using seismic events recorded by the MASE (100 seismometers running across central Mexico, 2005-2007) and VEOX (47 seismometers running across southern Mexico, 2007-2009) arrays, supplemented by stations from the National Seismic Network in Mexico (SSN). Using a spectral-decay method, we obtain a path attenuation operator t* for each seismogram in the frequency band 1 to 30 Hz, depending on the signal quality. These measurements are then inverted for 3D spatial variations in attenuation. Direct body-wave arrivals from local events are used for 3D velocity inversion. Deeper velocity structures along MASE and VEOX arrays are obtained by including teleseismic events. Inversion results show low attenuation associated with the Cocos slab, and show the slab dip angle increases from central to southern Mexico. High attenuation is imaged in the mantle wedge and the crust above. The highest attenuation is found in the crust near the active Los Tuxtlas volcanic field, probably related to the dehydration and melting process. Low velocity is observed in the mantle wedge and the crust above from velocity inversion. The Cocos slab is traced as high-velocity structure. The Cocos slab dips down to about 500 km in central Mexico along MASE array as shown by previous study (Perez-Campos, GRL, 2008). In southern Mexico along VEOX line, no clear continuous Cocos slab is observed deeper than about 150 km, which is also found by receiver function studies (Kim et al., in press; Perez-Campos et al., in press). There are some indications that the Cocos slab in southern Mexico near the Isthmus of Tehuantepec is truncated by some high-velocity structure dipping south from the Gulf of Mexico. This anomalous south-dipping structure is also seen in receiver function images, and may be related to the collision between the Yucatan Block and Mexico in the Miocene (Kim et al., in press).

  16. Petrology of HP/LT metapelitic rocks of an accretionary wedge, the Central Pontides, Turkey: evidence for tectonic stacking and syn-subduction exhumation

    Science.gov (United States)

    Aygül, Mesut; Okay, Aral; Oberhänsli, Roland

    2015-04-01

    Cretaceous HP/LT chloritoid-bearing metapelitic rocks crop out widely in the central part of the Pontides, northern Turkey. They are associated with eclogite to blueschist-facies metabasites and represent deep levels of an underplated subduction-accretion complex, which is tectonically overlain by low-grade HP phyllite/metasandstone intercalation along an extensional shear zone. Close to the shear zone, the footwall micaschists consist of quartz, phengite, paragonite, chlorite, rutile with syn-kinematic albite porphyroblast formed by pervasive shearing during exhumation. This type of micaschists is tourmaline-bearing and their retrograde nature suggests high-fluid flux along shear zones. Peak metamorphic assemblages are partly preserved in the chloritoid-micaschist farther away from the shear zone. Three peak metamorphic assemblages are identified and their PT conditions are constrained by pseudosections produced by Theriak-Domino and by Raman spectra of carbonaceous material: 1) garnet-chloritoid-glaucophane with lawsonite pseudomorphs (P: 17.5 ± 1 Kbar, T: 390-450 °C) 2) chloritoid with glaucophane pseudomorphs (P: 16-18 Kbar, T: 475 ± 40 °C) and 3) relatively high-Mg chloritoid (17%) with jadeite pseudomorphs (22-25 Kbar; T: 440 ± 30 °C) in addition to phengite, paragonite, quartz, chlorite, rutile. The last mineral assemblage is interpreted as transformation of the chloritoid + glaucophane assemblage to chloritoid + jadeite paragenesis with increasing pressure. Absence of tourmaline suggests that the chloritoid-micaschist did not interact with B-rich fluids during zero strain exhumation. Peak metamorphic assemblages and PT estimates suggest tectonic stacking within wedge with different depths of burial. 40Ar/39Ar phengite age of a pervasively sheared footwall micaschist is constrained to 100.6 ± 1.3 Ma and that of a chloritoid-micaschist is constrained to 91.8 ± 1.8 Ma suggesting exhumation during on-going subduction. Coupling and exhumation of the

  17. Molecular characteristics and virulence factors in methicillin-susceptible, resistant, and heterogeneous vancomycin-intermediate Staphylococcus aureus from central-southern China.

    Science.gov (United States)

    Liu, Cailin; Chen, Zhong-ju; Sun, Ziyong; Feng, Xianju; Zou, Mingxiang; Cao, Wei; Wang, Shanmei; Zeng, Ji; Wang, Yue; Sun, Mingyue

    2015-10-01

    Staphylococcus aureus is a leading cause of nosocomial infections. The purpose of this study was to evaluate the prevalence of methicillin-resistant S. aureus (MRSA) and heterogeneous vancomycin-intermediate S. aureus (hVISA), and compare the antimicrobial susceptibility, molecular characteristic, and virulence factors in methicillin-susceptible S. aureus (MSSA), MRSA, and hVISA from central-southern China. A total of 184 S. aureus were isolated from sterile body fluids. All isolates were subjected to population analysis profiling for the identification of hVISA phenotype and polymerase chain reaction analysis for genotyping and 31 virulence genes. The prevalence of MRSA isolates was 41.8% in central-southern China. Of 77 MRSA isolates, 17 (22.1%) were identified as hVISA. The most common MRSA and MSSA clones were ST239-MRSA-SCCmecIII-t030-agr-I (55.8%) and ST188-MSSA-t189-agr-I (20.6%), respectively. The frequency of carriage of pvl, hemolysins, tst, and staphylococcal enterotoxin genes among MSSA isolates was significantly higher than that for MRSA isolates (p aureus isolates; the virulence genes were more diverse and frequent among MSSA isolates than among MRSA isolates. Furthermore, the distribution of some virulence genes was correlated with the different S. aureus CCs. Copyright © 2014. Published by Elsevier B.V.

  18. Recreating Rocks

    DEFF Research Database (Denmark)

    Posth, Nicole R

    2008-01-01

    Nicole Posth and colleagues spent a month touring South African rock formations in their quest to understand the origin of ancient iron and silicate layers.......Nicole Posth and colleagues spent a month touring South African rock formations in their quest to understand the origin of ancient iron and silicate layers....

  19. Petroleum potential of lower and middle Paleozoic rocks in Nebraska portion of Mid-Continent

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, M.P. (Univ. of Nebraska, Lincoln (USA))

    1989-08-01

    Central North America during the Paleozoic was characterized by northern (Williston) and southern (Anadarko) depositional regimes separated by a stable Transcontinental arch. Nebraska lies on the southern flank of this arch and contains the northern zero edges of the lower and middle Paleozoic rocks of the southern regime. Most of these rocks are secondary dolomites with zones of excellent intercrystalline porosity. The Reagan-LaMotte Sandstones and the overlying Arbuckle dolomites are overlapped by Middle Ordovician rocks toward the Transcontinental arch. Rocks equivalent to the Simpson consist of a basal sand (St. Peter) and overlying interbedded gray-green shales and dolomitic limestones. An uppermost shale facies is present in the Upper Ordovician (Viola-Maquoketa) eastward and southward across Nebraska. The dolomite facies extends northward into the Williston basin. The Silurian dolomites, originally more widely deposited, are overlapped by Devonian dolomites in southeastern Nebraska. Upper Devonian rocks exhibit a regional facies change from carbonate to green-gray shale to black shale southeastward across the Mid-Continent. Mississippian carbonates overlap the Devonian westward and northward across the Transcontinental arch. Pennsylvanian uplift and erosion were widespread, producing numerous stratigraphic traps. Sands related to the basal Pennsylvanian unconformity produce along the Cambridge arch. Arbuckle, Simpson, Viola, and Hunton production is present in the Forest City basin and along the Central Kansas uplift. Although source rocks are scarce and the maturation is marginal, current theories of long-distance oil migration encourage exploration in the extensive lower and middle Paleozoic reservoirs in this portion of the Mid-Continent.

  20. Art Rocks with Rock Art!

    Science.gov (United States)

    Bickett, Marianne

    2011-01-01

    This article discusses rock art which was the very first "art." Rock art, such as the images created on the stone surfaces of the caves of Lascaux and Altimira, is the true origin of the canvas, paintbrush, and painting media. For there, within caverns deep in the earth, the first artists mixed animal fat, urine, and saliva with powdered minerals…

  1. Rock Physics

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    2017-01-01

    Rock physics is the discipline linking petrophysical properties as derived from borehole data to surface based geophysical exploration data. It can involve interpretation of both elastic wave propagation and electrical conductivity, but in this chapter focus is on elasticity. Rock physics is based...... on continuum mechanics, and the theory of elasticity developed for statics becomes the key to petrophysical interpretation of velocity of elastic waves. In practice, rock physics involves interpretation of well logs including vertical seismic profiling (VSP) and analysis of core samples. The results...

  2. A brief study on the imprints of seismo tectonic activities in the crust of central and southern Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, K.V.L.N.S.; Subrahmanyam, A.S.; Subrahmanyam, V.; Murty, G.P.S.; Rao, K.M.

    the Southern Ba~ of Bengal. particularly from II' N to I YN lat. to dra\\\\ inferences on the stability of the area. Close grid geophysical data acquisition is necessary in the posl- Tsunami scenario to study any major Iminor changes O\\'er this pan of Tamil Nadu... and geological data acquisition. Weextend our si ncere thanks 10 the officers and crew of the Sagar Sukthi who helped in collection of the data. References Curray. l.R. and Moore D.G. (1971). Groll'thof rlre Bellgal deep sea fall alld delll/darioll ill rhe...

  3. Petrogenesis and tectonic settings of volcanic rocks of the Ashele Cu-Zn deposit in southern Altay, Xinjiang, Northwest China: Insights from zircon U-Pb geochronology, geochemistry and Sr-Nd isotopes

    Science.gov (United States)

    Wu, Yufeng; Yang, Fuquan; Liu, Feng; Geng, Xinxia; Li, Qiang; Zheng, Jiahao

    2015-11-01

    The Early-Mid-Devonian Ashele Formation of the southern margin of the Chinese Altay hosts the Ashele Cu-Zn volcanogenic massive sulfide (VMS) deposit and consists of intercalated volcanic and sedimentary rocks that have experienced regional greenschist-facies metamorphism. We studied the petrography, zircon U-Pb geochronology, geochemistry, and Sr-Nd isotopes of dacites and basalts in order to understand the petrogenesis of these rocks and the regional tectonic evolution. Two dacites yielded LA-MC-ICP-MS zircon U-Pb ages of 402 ± 6 Ma and 403 ± 2 Ma. The dacites are calc-alkaline, and characterized by high Na2O/K2O ratios (3.6-9.3), and high Mg# values (47-63), enrichment in large ion lithophile elements (LILE) and light rare earth elements (LREE), depletion in Nb, Ta, Ti, and P, and relatively positive εNd(t) values (+3.6 to +7.5), collectively suggesting a sanukitic magma affinity. The variations in the major and trace elements of the dacites indicate that Fe-Ti oxide, plagioclase, and apatite were fractionated during their petrogenesis. The basalts are tholeiitic, and are characterized by high Mg# values (66-73), and negative Nb and Ta anomalies. The geochemical characteristics of the basalts are similar to those of N-MORB. Those characteristics together with the positive εNd(t) values (+6.8 to +9.2) of the basalts, indicate that the precursor magma was derived mainly from an N-MORB-type depleted asthenospheric mantle in an island arc setting. The geochemical similarities between the basalts and dacites indicate that they both originated from a similar depleted mantle source via partial melting under different magmatic conditions in each case, possibly related to ridge subduction.

  4. Bulk rock composition and geochemistry of olivine-hosted melt inclusions in the Grey Porri Tuff and selected lavas of the Monte dei Porri volcano, Salina, Aeolian Islands, southern Italy

    Science.gov (United States)

    Doherty, Angela; Bodnar, Robert; Vivo, Benedetto; Bohrson, Wendy; Belkin, Harvey; Messina, Antonia; Tracy, Robert

    2012-06-01

    The Aeolian Islands are an arcuate chain of submarine seamounts and volcanic islands, lying just north of Sicily in southern Italy. The second largest of the islands, Salina, exhibits a wide range of compositional variation in its erupted products, from basaltic lavas to rhyolitic pumice. The Monte dei Porri eruptions occurred between 60 ka and 30 ka, following a period of approximately 60,000 years of repose. The bulk rock composition of the Monte dei Porri products range from basaltic-andesite scoria to andesitic pumice in the Grey Porri Tuff (GPT), with the Monte dei Porri lavas having basaltic-andesite compositions. The typical mineral assemblage of the GPT is calcic plagioclase, clinopyroxene (augite), olivine (Fo72-84) and orthopyroxene (enstatite) ± amphibole and Ti-Fe oxides. The lava units show a similar mineral assemblage, but contain lower Fo olivines (Fo57-78). The lava units also contain numerous glomerocrysts, including an unusual variety that contains quartz, K-feldspar and mica. Melt inclusions (MI) are ubiquitous in all mineral phases from all units of the Monte dei Porri eruptions; however, only data from olivine-hosted MI in the GPT are reported here. Compositions of MI in the GPT are typically basaltic (average SiO2 of 49.8 wt %) in the pumices and basaltic-andesite (average SiO2 of 55.6 wt %) in the scoriae and show a bimodal distribution in most compositional discrimination plots. The compositions of most of the MI in the scoriae overlap with bulk rock compositions of the lavas. Petrological and geochemical evidence suggest that mixing of one or more magmas and/or crustal assimilation played a role in the evolution of the Monte dei Porri magmatic system, especially the GPT. Analyses of the more evolved mineral phases are required to better constrain the evolution of the magma.

  5. Bulk rock composition and geochemistry of olivine-hosted melt inclusions in the Grey Porri Tuff and selected lavas of the Monte dei Porri volcano, Salina, Aeolian Islands, southern Italy

    Science.gov (United States)

    Doherty, Angela L.; Bodnar, Robert J.; De Vivo, Benedetto; Bohrson, Wendy A.; Belkin, Harvey E.; Messina, Antonia; Tracy, Robert J.

    2012-01-01

    The Aeolian Islands are an arcuate chain of submarine seamounts and volcanic islands, lying just north of Sicily in southern Italy. The second largest of the islands, Salina, exhibits a wide range of compositional variation in its erupted products, from basaltic lavas to rhyolitic pumice. The Monte dei Porri eruptions occurred between 60 ka and 30 ka, following a period of approximately 60,000 years of repose. The bulk rock composition of the Monte dei Porri products range from basaltic-andesite scoria to andesitic pumice in the Grey Porri Tuff (GPT), with the Monte dei Porri lavas having basaltic-andesite compositions. The typical mineral assemblage of the GPT is calcic plagioclase, clinopyroxene (augite), olivine (Fo72−84) and orthopyroxene (enstatite) ± amphibole and Ti-Fe oxides. The lava units show a similar mineral assemblage, but contain lower Fo olivines (Fo57−78). The lava units also contain numerous glomerocrysts, including an unusual variety that contains quartz, K-feldspar and mica. Melt inclusions (MI) are ubiquitous in all mineral phases from all units of the Monte dei Porri eruptions; however, only data from olivine-hosted MI in the GPT are reported here. Compositions of MI in the GPT are typically basaltic (average SiO2 of 49.8 wt %) in the pumices and basaltic-andesite (average SiO2 of 55.6 wt %) in the scoriae and show a bimodal distribution in most compositional discrimination plots. The compositions of most of the MI in the scoriae overlap with bulk rock compositions of the lavas. Petrological and geochemical evidence suggest that mixing of one or more magmas and/or crustal assimilation played a role in the evolution of the Monte dei Porri magmatic system, especially the GPT. Analyses of the more evolved mineral phases are required to better constrain the evolution of the magma.

  6. Applications and limitations of thermobarometry in migmatites and granulites using as an example rocks of the Araçuaí Orogen in southern Bahia, including a discussion on the tectonic meaning of the current results

    Directory of Open Access Journals (Sweden)

    Renato Moraes

    Full Text Available In southern Bahia, there are outcrops of migmatites and granulites in the Jequitinhonha Complex, which is part of the northern portion of the Araçuaí Orogen. Migmatites (garnet-cordierite diatexite dominate the metamorphic rocks and host lenses and layers of felsic garnet granulite. The conditions of temperature and pressure of metamorphism were calculated using conventional thermobarometry and the software THERMOCALC. Values around 850 °C and 7 kbar were obtained with THERMOCALC. The calculations for the garnet-cordierite diatexite were made considering aH2O equal to 1, but the best results of calculations for the granulites are obtained with aH2O values of 0.3. Pressure values obtained with GAPES resulted in consistent values with THERMOCALC, but the pair garnet-orthopyroxene always produces low values for temperature and high ones for pressure. The results are consistent with the presence of the pair garnet and cordierite in diatexite and orthopyroxene in felsic granulite. From the tectonic point of view, the setting in which metamorphism of these rocks occurred requires high heat flow with a thermal anomaly in mid continental crust, as indicated by values of 7 kbar. Recent studies have favored the closure of a back-arc basin for this tectonic setting, but it does not solve the problem that the time span between metamorphic peak and the end of granite intrusions, involving large bodies of charnockite, is more than 80 million years. The model of tectonic switching is suggested here as it can explain the maintenance of high temperatures for a more extended interval of time.

  7. From velocity and attenuation tomography to rock physical modeling: Inferences on fluid-driven earthquake processes at the Irpinia fault system in southern Italy

    Science.gov (United States)

    Amoroso, O.; Russo, G.; De Landro, G.; Zollo, A.; Garambois, S.; Mazzoli, S.; Parente, M.; Virieux, J.

    2017-07-01

    We retrieve 3-D attenuation images of the crustal volume embedding the fault system associated with the destructive Ms 6.9, 1980 Irpinia earthquake by tomographic inversion of t* measurements. A high QP anomaly is found to be correlated with the 1980 fault geometry, while the QS model shows regional-scale variations related to the NE edge of the uplifted pre-Tertiary limestone. An upscaling strategy is used to infer rock properties such as porosity, consolidation, type of fluid mixing, and relative saturation percentage at 8-10 km fault depth. We constrain the porosity and consolidation in the ranges 4-5% and 5-9, respectively, with the possible fluid mixes being both brine-CO2 and CH4-CO2. The consolidation parameter range indicates high pore pressures at the same depths. These results support the evidence for a fracture system, highly saturated in gases and a seismicity triggering mechanism at the fault zone, which is strongly controlled by fluid-induced pore pressure changes.

  8. Carboniferous-Permian volcanic evolution in Central Europe-U/Pb ages of volcanic rocks in Saxony (Germany) and northern Bohemia (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Hoffmann, U.; Breitkreuz, Ch.; Breiter, Karel; Sergeev, S.; Stanek, K.; Tichomirowa, M.

    2013-01-01

    Roč. 102, č. 1 (2013), s. 73-99 ISSN 1437-3254 Institutional support: RVO:67985831 Keywords : pyroclastic rocks * dykes * stratigraphy * SHRIMP U/Pb ages * Pb/Pb single zircon age * Variscides Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.084, year: 2013

  9. On the intraspecific variation in morphometry and shape of sagittal otoliths of common sardine, Strangomera bentincki, off central-southern Chile

    Directory of Open Access Journals (Sweden)

    Sandra Curin-Osorio

    2012-11-01

    Full Text Available Size and shape of fish otoliths are species-specific, but some species also display intraspecific variations. The common sardine, Strangomera bentincki, is a small pelagic fish inhabiting a seasonal upwelling ecosystem off central-southern Chile, having two discrete spawning sites along its latitudinal distribution. Otoliths of specimens were collected from commercial catches in Talcahuano and Corral, representing the central and south spawning zones. On the basis of otolith images, size-based shape descriptors were used to detect ontogenetic variation, and morphometric variables (length, breadth, area, perimeter and weight were used to detect geographical differences in size and shape of otoliths. Outline analysis was studied on the basis of elliptic Fourier descriptors through multivariate statistical procedures. Size-based shape descriptors showed that otolith shape starts to be stable for fish larger than 12 cm total length, which keep an elliptical form. Morphometric variables for fish larger than 12 cm revealed intraspecific variation between central and south zones, which were associated with otolith weight and breadth. Outline analysis did not reveal significant spatial differences, but extreme intraspecific variation was due to the antirostrum, excisure, and posterior part of otoliths. Intraspecific variation in otolith size could be linked to differences in each spawning habitat and related to geographical origin, whose differences are not clearly identified. It is concluded that intraspecific variability in morphometric variables of sardine otoliths revealed geographic differences in size that are not attributable to allometric effects, and that otolith shape was similar between specimens from different geographic origin.

  10. Mapping Vegetation Morphology Types in Southern Africa Savanna Using MODIS Time-Series Metrics: A Case Study of Central Kalahari, Botswana

    Directory of Open Access Journals (Sweden)

    Niti B. Mishra

    2015-03-01

    Full Text Available Savanna ecosystems are geographically extensive and both ecologically and economically important; they therefore require monitoring over large spatial extents. There are, in particular, large areas within southern Africa savanna ecosystems that lack consistent geospatial data on vegetation morphological properties, which is a prerequisite for biodiversity conservation and sustainable management of ecological resources. Given the challenges involved in distinguishing and mapping savanna vegetation assemblages using remote sensing, the objective of this study was to develop a vegetation morphology map for the largest protected area in Africa, the central Kalahari. Six vegetation morphology classes were developed and sample training/validation pixels were selected for each class by analyzing extensive in situ data on vegetation structural and functional properties, in combination with existing ancillary data and coarse scale land cover products. The classification feature set consisted of annual and intra annual matrices derived from 14 years of satellite-derived vegetation indices images, and final classification was achieved using an ensemble tree based classifier. All vegetation morphology classes were mapped with high accuracy and the overall classification accuracy was 91.9%. Besides filling the geospatial data gap for the central Kalahari area, this vegetation morphology map is expected to serve as a critical input to ecological studies focusing on habitat use by wildlife and the efficacy of game fencing, as well as contributing to sustainable ecosystem management in the central Kalahari.

  11. Geochemical, mineralogical and Re-Os isotopic constraints on the origin of Tethyan oceanic mantle and crustal rocks from the Central Pontides, northern Turkey

    Science.gov (United States)

    Çelik, Ömer Faruk; Marzoli, Andrea; Marschik, Robert; Chiaradia, Massimo; Mathur, Ryan

    2017-06-01

    Chromite, ultramafic and mafic rocks from Eldivan, Yapraklı, Ayli Dağ, Küre, Elekdağ and Kızılırmak in northern Turkey have been studied to determine their mineral and whole-rock geochemical, and Re-Os isotope geochemical characteristics. Most of the studied peridotites display depleted but commonly V-shaped chondrite-normalized rare-earth element (REE) patterns while some peridotites as well as pyroxenites from all areas exhibit light REE depleted patterns. Olivine (forsterite 82 to 92 mol%) and spinel (chromium number 13 to 63) in the studied peridotites exhibit a wide range of compositions. Compositions of spinels suggest that peridotites from Eldivan, Ayli Dağ and Küre experienced relatively large degrees of partial melting ( 15 and 19 wt%), whereas those of the Kızılırmak area most likely reflect lower melting degrees ( 4-6 wt%). Whole-rock and mineral chemical data indicate that the ultramafic rocks are similar to abyssal and supra-subduction zone peridotites. The ultramafic rocks of the investigated areas exhibit a wide range of 187Re/188Os (0.12 to 6.6) and measured 187Os/188Os (0.122-1.14), while the basaltic rocks from Küre, Eldivan and Kızılırmak areas have high 187Re/188Os (128-562) and measured 187Os/188Os (0.724-1.943). On the other hand, chromite from Eldivan, Elekdağ and Kızılırmak show high Os contents (21.81-44.04 ppb) and low 187Re/188Os (0.015-0.818) and 187Os/188Os (0.122-0.133). Re-Os model ages (TChur) for all analyzed samples yielded scattered ages ranging from Jurassic to Proterozoic. Overall, geochemical data are interpreted to reflect different degrees of partial melting, melt - rock interactions and metasomatic effects that produced a heterogeneous mantle in a supra-subduction setting.

  12. SHRIMP U-Pb dating and geochemistry of the Cretaceous plutonic rocks in the Korean Peninsula: A new tectonic model of the Cretaceous Korean Peninsula

    Science.gov (United States)

    Kim, Sung Won; Kwon, Sanghoon; Park, Seung-Ik; Lee, Changyeol; Cho, Deung-Lyong; Lee, Hong-Jin; Ko, Kyoungtae; Kim, Sook Ju

    2016-10-01

    The Cretaceous tectonomagmatism of the Korean Peninsula was examined based on geochemical and geochronological data of the Cretaceous plutonic rocks, along with distribution of volcano-sedimentary nonmarine N- to NE-trending fault bounded sedimentary basins. We conducted sensitive high-resolution ion microprobe (SHRIMP) zircon U-Pb ages and whole-rock geochemical compositions of 21 Cretaceous plutonic rocks, together with previously published data, from the central to southern Korean Peninsula. Four age groups of plutonic rocks were identified: Group I (ca. 119-106 Ma) in the northern to central area, Group II (ca. 99-87 Ma) in the central southern area, Group III (ca. 85-82 Ma) in the central to southern area, and Group IV (ca. 76-67 Ma) in the southernmost area. These results indicate a sporadic trenchward-younging trend of the Cretaceous magmatism in the Korean Peninsula. The Group I, II, and III rocks are dominated by high-K calc-alkaline I-type rocks with rift-related A-type granitoids. In contrast, the Group IV rocks are high-K calc-alkaline I-type plutonic rocks with no A-type rocks. The geochemical signatures of the entire groups indicated LREEs (light rare earth elements) enrichments and negative Nb, Ta, and Ti anomalies, indicating normal arc magmatism. A new tectonic model of the Cretaceous Korean Peninsula was proposed based on temporal and spatial distribution of the Cretaceous plutons represented by four age groups; 1) magmatic quiescence throughout the Korean Peninsula from ca. 160 to 120 Ma, 2) intrusions of the I- and A-type granitoids in the northern and central Korean Peninsula (Group I plutonic rocks from ca. 120 to 100 Ma) resulted from the partial melting of the lower continental crust due to the rollback of the Izanagi plate expressed as the conversion from flat-lying subduction to normal subduction. The Gyeongsang nonmarine sedimentary rift basin in the Korean Peninsula and adakite magmatism preserved in the present-day Japanese Islands

  13. Interpretation of the last-glacial vegetation of eastern central Europe using modern analogues from southern Siberia

    Czech Academy of Sciences Publication Activity Database

    Kuneš, P.; Pelánková, Barbora; Chytrý, M.; Jankovská, Vlasta; Pokorný, Petr; Petr, L.

    2008-01-01

    Roč. 35, č. 12 (2008), s. 2223-2236 ISSN 0305-0270 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z80020508 Keywords : fossil pollen spectra * Central Europe * forest Subject RIV: EF - Botanics Impact factor: 4.566, year: 2008

  14. Potassium Fertilization for Long Term No-Till Crop Rotation in the Central-Southern Region of Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Renan Costa Beber Vieira

    Full Text Available ABSTRACT Fertilization programs for annual crops in the state of Paraná, southern Brazil, are based on studies that focused on conventional tillage and were established more than 30 years ago. The primary purpose of this study was to assess potassium (K fertilization on long-term (>30 years no-tillage soybean, corn, wheat, and barley crops grown in rotation on Oxisols in the central-southern region of Paraná. A total of 47 experiments were carried out from 2008 to 2013, three of which addressed K calibration and the other 44, crop response to K fertilization. Critical K soil-test value and interpretation classes were established from the ratio between relative crop yield [RY = (yield without K/max yield × 100] and soil K levels. Winter cereals were found to be more demanding of K than were soybean and corn; also, the former governed critical K soil-test value for crop rotation: 0.23 cmolc dm-3 in the 0.00-0.20 m soil layer. Recommended fertilization rates for soils in the low and medium soil K levels were established by using the build-up approach for soil correction; and those for the high and very high soil K levels were established by removing K at harvest and assessing economic return in crop response experiments. The K rates calculated for the high yield classes exceeded those currently recommended for use in Paraná.

  15. Prevalence and acceptance of tattoos and piercings: a survey of young adults from the southern German-speaking area of Central Europe.

    Science.gov (United States)

    Stieger, Stefan; Pietschnig, Jakob; Kastner, Cornelia K; Voracek, Martin; Swami, Viren

    2010-06-01

    The present study examined the prevalence and acceptance of body piercings and tattoos among a community sample from the southern German-speaking area of Central Europe. A total of 440 respondents completed information about their own body piercings and tattoos and reported whether they would be likely never to have piercings and tattoos in the future. Analyses indicated that 19.8 and 15.2% of respondents had piercings (excluding the earlobe) and tattoos, respectively. Women were more likely to have body piercings than men, but there were no sex differences in tattooing. There were also few sociodemographic differences in piercings and tattoos, and most participants reported being likely to consider body art in the future. These results are considered in relation to prevalence estimates of body art in other Western countries and the associated health risks.

  16. Notes on the Strumariinae (Amaryllidaceae-Amaryllideae. Six new taxa in Strumaria and Hessea from the central and northwestern Cape, South Africa, and southern Namibia

    Directory of Open Access Journals (Sweden)

    D. J. Snijman

    1992-12-01

    Full Text Available Newly described are four species and a subspecies of Strumaria and one species of Hessea. S.  aestivalis  Snijman from the Langberg and  S. perryae Snijman from the Bokkeveld escarpment are rare species closely allied to S. pubescens W.F. Barker.  S. discifera Marloth ex Snijman is widespread on the Bokkeveld and Roggeveld escarpments but S. discifera subsp. bulbifera Snijman which comprises several clonal populations, is narrowly restricted to the dolerite ridges near Nieuwoudtville. S.  villosa Snijman, a rare species, is localised on quartz hills near Kosies in the Richtersveld.  H. speciosa Snijman occurs in red sand and friable loam from southern Namibia to the central Cape.

  17. Deciphering the mid-Carboniferous eustatic event in the central Appalachian foreland basin, southern West Virginia, USA

    Science.gov (United States)

    Blake, B.M.; Beuthin, J.D.

    2008-01-01

    A prominent unconformity, present across shallow shelf areas of the Euramerican paleoequatorial basins, is used to demark the boundary between the Mississippian and Pennsylvanian subsystems. This unconformity, the mid-Carboniferous eustatic event, is generally attributed to a major glacio-eustatic sea-level fall. Although a Mississippian-Pennsylvanian unconformity is recognized throughout most of the Appalachian region, the record of the mid-Carboniferous eustatic event in the structurally deepest part of the basin has been controversial. Based on early reports that suggested the most complete Pennsylvanian section was present in southern West Virginia, various conceptual depositional models postulated continuous sedimentation between the youngest Mississippian Bluestone Formation and the oldest Penn-sylvanian Pocahontas Formation. In contrast, tabular-erosion models envisioned axial drainage systems that evolved in response to changing basin dynamics. These models predicted a Mississippian-Pennsylvanian unconformity. All these models suffered from a lack of biostratigraphic control. The presence of a sub-Pocahontas paleovalley, herein named the Lashmeet paleovalley, has been confirmed in southern West Virginia. The Lashmeet paleovalley was incised over 35 m into Bluestone strata and filled by lithic sands derived from the Appalachian orogen to the northeast and east. The polygenetic Green Valley paleosol complex marks the Bluestone-Pocahontas contact on associated interfluves. Together, these features indicate a substantial period of subaerial exposure and argue strongly in favor of a Mississippian-Pennsylvanian unconformity. Paleontologic data from the Bluestone Formation, including marine invertebrates and conodonts from the marine Bramwell Member and paleofloral data, support a late, but not latest, Arnsbergian age assignment. Marine fossils are not known from the Pocahontas Formation, but macrofloral and palynomorph taxa support a Langsettian age for most of

  18. Dissolved rare earth elements in the central-western sector of the Ross Sea, Southern Ocean: Geochemical tracing of seawater masses.

    Science.gov (United States)

    Turetta, Clara; Barbaro, Elena; Capodaglio, Gabriele; Barbante, Carlo

    2017-09-01

    The present essay contributes to the existing literature on rare earth elements (REEs) in the southern hemisphere by presenting the first data, to our knowledge, on the vertical profiles of dissolved REEs in 71 samples collected in the central-western sector of the Ross Sea (Southern Ocean-SO). The REEs were measured in the water samples collected during the 2002-2003 and 2005-2006 austral summers. 4 samples were collected and analysed in the framework of a test experiment, as part of the WISSARD Project (Whillans Ice Stream Subglacial Access Research Drilling). Our results show significant differences between the REE patterns of the main water masses present in the SO: we could observe specific signature in the High Salinity Shelf Water (HSSW), Ice Shelf Water (ISW) and Low Salinity Shelf Water (LSSW). A significant increase in Terbium (Tb) concentration was observed in the HSSW and ISW, the two principal water masses contributing to the formation of Antarctic Bottom Water (AABW) in the Ross Sea area, and in LSSW. Some of the HSSW samples show enrichment in Neodymium (Nd). Dissolved REE could therefore be used as tracers to understand the deep circulation of the SO (Pacific sector). We hypothesize that: (I) the characteristic dissolved REE pattern may derive from the composition of source area and from the hydrothermal activity of the central-western area of the Ross Sea; (II) the Tb anomaly observed in the AABW on the South Australian platform could be partially explained by the contribution of AABW generated in the Ross Sea region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Volatiles in Olivine Hosted Melt Inclusions from Small Eruptive Centers of the Central Southern Volcanic Zone (CSVZ), Chile

    Science.gov (United States)

    Wacaster, S.; Hickey-Vargas, R.; Wallace, P.

    2008-12-01

    This study is a geochemical analysis of basaltic scoria cones of the CSVZ, where bulk rock analyses have revealed two predominant lava types. We consider the relationship of cones to nearby stratovolcanos and the proximity of both to the Liquine-Ofqui Fault Zone to understand how primitive melts with wide ranging compositions are generated. We characterize melt inclusions to see if they show similar trends as bulk rocks and to evaluate degassing of melts during ascent and crystallization. We report new CO2, H2O, F, S, and Cl data collected by SIMS and FTIR. Type 1 and Type 2 lavas have been identified in prior studies. Type 1 rocks have significant 238U/232Th excesses and higher abundances of fluid mobile elements. Type 2 lavas and scorias have higher LREE/HREE ratios, lower abundances of fluid mobile elements, lower 87Sr/86Sr and U- series isotopes near secular equilibrium. Type 1, usually associated with composite volcanic centers, erupt at one cone in our field area, while Type 2 is found only at other individual cones aligned with the LOFZ. We characterize olivine-hosted melt inclusions with emphasis on volatile element analyses to test the hypotheses of flux melting beneath Type 1 centers versus a lesser extent of decompression melting beneath Type 2 centers. Melt inclusions show the following overall ranges of volatiles: CO2: below detection-1208 ppm; H2O(Total): 0.11-3.9 wt percent: F: 52-1442 ppm; S: 34-2884 ppm, and Cl: 177-1606 ppm. Inclusions from lavas are generally more degassed when compared to those from scoria for CO2 and H2O. Some Cl and F values are lower in inclusions from lavas, but not all. Sulfur is variably degassed in melt inclusions from both lavas and scoria. Melt inclusions from Type 2 Caburgua scoria show evidence for variable degassing and crystallization pressures. One subset of the inclusions were trapped at low pressures (P CO2 CO2 (1.5-4.0 wt % and 300-800 ppm and all under 1100 bars). Type I San Jorge melt inclusions also show

  20. Re-appraisal of the Santa Rita Greenstone Belt stratigraphy, central Brazil, based on new U-Pb SHRIMP age and Sm-Nd data of felsic metavolcanic rocks

    Energy Technology Data Exchange (ETDEWEB)

    Pimentel, Marcio Martins; Jost, Hardy; Fuck, Reinhardt Adolfo; Junges, Sergio Luiz [Brasilia Univ., DF (Brazil). Inst. de Geociencias]. E-mail: marcio@unb.br; Armstrong, Richard [Australian National Univ., Canberra, ACT (Australia). Research School of Earth Sciences; Resende, Marcelo Goncalves [Universidade Catolica de Brasilia, DF (Brazil). Curso de Graduacao em Engenharia Ambiental

    2000-03-01

    The Santa Rita greenstone belt represents one of the supracrustal belts of the Archaen terranes of Goias, central Brazil. The stratigraphic sequence of this greenstone belt comprises a lower of komatities and basalts and an upper metasedimentary unit made of carbonaceous schits, chert, iron formation and marble, unconformably overlain by clastic metasedimentary rocks. Felsic metavolcanics occur at the interface between the metabasalts and the upper metasedimentary pile. U-Pb SHRIMP age for zircons from the felsic metavolcanics reveal that it is not part of the Archaean sequence, but represents the product of mesoproterozoic (1580 {+-} 12 Ma) magmatic event. Sm-Nd isotopic data (initial e{sub CHUR} values between -10.5 and -14.9) and T{sub DM} values of 3.0 and 3.2 Ga, within the range of the surrounding TTG terranes, indicate that the original felsic magmas were produced by re-melting of Archaen crust. The data demonstrate that the Goias greenstone belt contains infolded and imbricated proterozoic rocks, as previously suggested by Sm-Nd isotopic analyses of some of the upper detrital metasedimentary rocks. (author)

  1. Age constraints on Late Paleozoic evolution of continental crust from electron microprobe dating of monazite in the Peloritani Mountains (southern Italy): another example of resetting of monazite ages in high-grade rocks

    Science.gov (United States)

    Appel, Peter; Cirrincione, Rosolino; Fiannacca, Patrizia; Pezzino, Antonino

    2011-01-01

    In situ monazite microprobe dating has been performed, for the first time, on trondhjemite and amphibolite facies metasediments from the Peloritani Mountains in order to obtain information about the age of metamorphism and intrusive magmatism within this still poorly known sector of the Hercynian Belt. All samples show single-stage monazite growth of Hercynian age. One migmatite and one biotitic paragneiss yielded monazite ages of 311 ± 4 and 298 ± 6 Ma, respectively. These ages fit with previous age determinations in similar rocks from southern Calabria, indicating a thermal metamorphic peak at about 300 Ma, at the same time as widespread granitoid magmatism. The older of the two ages might represent a slightly earlier event, possibly associated with the emplacement of an adjacent trondhjemite pluton, previously dated by SHRIMP at 314 Ma. No evidence for pre-Hercynian events and only a little indication for some monazite crystallization starting from ca. 360 Ma were obtained from monazite dating of the metasediments, suggesting either a single-stage metamorphic evolution or a significant resetting of the monazite isotope system during the main Hercynian event (ca. 300 Ma). Rare monazite from a trondhjemite sample yields evidence for a late-Hercynian age of about 275 Ma. This age is interpreted as representing a post-magmatic stage of metasomatic monazite crystallization, which significantly postdates the emplacement of the original magmatic body.

  2. River-spring connectivity and hydrogeochemical interactions in a shallow fractured rock formation. The case study of Fuensanta river valley (Southern Spain)

    Science.gov (United States)

    Barberá, J. A.; Andreo, B.

    2017-04-01

    In upland catchments, the hydrology and hydrochemistry of streams are largely influenced by groundwater inflows, at both regional and local scale. However, reverse conditions (groundwater dynamics conditioned by surface water interferences), although less described, may also occur. In this research, the local river-spring connectivity and induced hydrogeochemical interactions in intensely folded, fractured and layered Cretaceous marls and marly-limestones (Fuensanta river valley, S Spain) are discussed based on field observations, tracer tests and hydrodynamic and hydrochemical data. The differential flow measurements and tracing experiments performed in the Fuensanta river permitted us to quantify the surface water losses and to verify its direct hydraulic connection with the Fuensanta spring. The numerical simulations of tracer breakthrough curves suggest the existence of a groundwater flow system through well-connected master and tributary fractures, with fast and multi-source flow components. Furthermore, the multivariate statistical analysis conducted using chemical data from the sampled waters, the geochemical study of water-rock interactions and the proposed water mixing approach allowed the spatial characterization of the chemistry of the springs and river/stream waters draining low permeable Cretaceous formations. Results corroborated that the mixing of surface waters, as well as calcite dissolution and CO2 dissolution/exsolution, are the main geochemical processes constraining Fuensanta spring hydrochemistry. The estimated contribution of the tributary surface waters to the spring flow during the research period was approximately 26-53% (Fuensanta river) and 47-74% (Convento stream), being predominant the first component during high flow and the second one during the dry season. The identification of secondary geochemical processes (dolomite and gypsum dissolution and dedolomitization) in Fuensanta spring waters evidences the induced hydrogeochemical

  3. THE CENTRALITY OF THE PROCESSES OF CENTRAL AND SOUTHERN ASIA FOR THE GLOBAL SECURITY; AS VIEWED BY THE AMERICAN FOREIGN POLICY

    Directory of Open Access Journals (Sweden)

    OLGA LEPIJINA

    2018-01-01

    Full Text Available During his presidential campaign, Barack Obama announced the withdrawal of U.S. troops from Iraq. Such a statement could be interpreted as a contrast to the extremely unpopular foreign policy of President Bush, as well as a response to the feeling of the majority of Americans wishing their people not to being killed abroad. However, this meant nothing less than the concentration of the U.S. effort wasted in Iraq, for use it in a front of much greater importance such as Afghanistan. The origins of this change in the orientation of American foreign policy lies in the recognition of the assumption, according to which neither Iraq nor the Middle East, but Afghanistan and Pakistan, along with the newly independent states of post-Soviet Central Asia are the key area for U.S. and the entire West security. Precisely in this region the Islamic threat, embodied in organizations like the taliban and Al Qaeda, is concentrated. These organizations do not act for themselves but supported by the security services and Pakistani troops who use them for its own geopolitical aims in its rivalry with India.

  4. An endolithic microbial community in dolomite rock in central Switzerland: characterization by reflection spectroscopy, pigment analyses, scanning electron microscopy, and laser scanning microscopy.

    Science.gov (United States)

    Horath, T; Neu, T R; Bachofen, R

    2006-04-01

    A community of endolithic microorganisms dominated by phototrophs was found as a distinct band a few millimeters below the surface of bare exposed dolomite rocks in the Piora Valley in the Alps. Using in situ reflectance spectroscopy, we detected chlorophyll a (Chl a), phycobilins, carotenoids, and an unknown type of bacteriochlorophyll-like pigment absorbing in vivo at about 720 nm. In cross sections, the data indicated a defined distribution of different groups of organisms perpendicular to the rock surface. High-performance liquid chromatography analyses of pigments extracted with organic solvents confirmed the presence of two types of bacteriochlorophylls besides chlorophylls and various carotenoids. Spherical organisms of varying sizes and small filaments were observed in situ with scanning electron microscopy and confocal laser scanning microscopy (one- and two-photon technique). The latter allowed visualization of the distribution of phototrophic microorganisms by the autofluorescence of their pigments within the rock. Coccoid cyanobacteria of various sizes predominated over filamentous ones. Application of fluorescence-labeled lectins demonstrated that most cyanobacteria were embedded in an exopolymeric matrix. Nucleic acid stains revealed a wide distribution of small heterotrophs. Some biological structures emitting a green autofluorescence remain to be identified.

  5. Pre-Messinian (Sub-Salt Source-Rock Potential on Back-Stop Basins of the Hellenic Trench System (Messara Basin, Central Crete, Greece

    Directory of Open Access Journals (Sweden)

    Maravelis A.

    2016-01-01

    Full Text Available The Greek part of the Mediterranean Ridge suggests, in terms of its hydrocarbon potential, further frontier exploration. The geological similarities between its prolific portions, within the Cyprus and Egyptian Exclusive Economic Zones, indicate possible recoverable natural gas reserves in its Greek portion. Nevertheless it lacks of systematic frontier exploration although direct petroleum indicators occur. Active mud volcanoes on the Mediterranean Ridge, still emitting concurrently gas and gas hydrates, have not been yet assessed even though are strongly related to hydrocarbon occurrence worldwide (Caspian Sea, Gulf of Mexico, Western African Basin, Trinidad-Tobago, the Nile Cone. For this reason, the source rock potential of the Late Miocene lacustrine deposits on a backstop basin of the Hellenic Trench System (Messara Basin, Crete, Greece, was studied. The obtained pyrolysis data indicate that the containing organic matter is present in sufficient abundance and with good enough quality to be regarded as potential source rocks. The observed type III kerogen suggests gas generation potential. Although indications of higher thermal evolution occur the studied rocks suggest low maturation levels. The biogenic gas seeps in the studied research well further demonstrate the regional gas generation potential.

  6. Magnetic fabrics in overthrusted terrains: example from the Buntsandstein Facies in the southern edge of the Axial Zone (Nogueres unit, Central Pyrenees)

    Science.gov (United States)

    Izquierdo Llavall, E.; Casas Sainz, A.; Oliva Urcia, B.

    2012-04-01

    Magnetic fabrics in deformed domains are a source of information of the strain rate and the tectonic evolution of the rocks. The present study shows the results derived from the application of this methodological approach to the Permian-Triassic red beds in the western sector of the Nogueres unit and eastern sector of the Gavarnie thrust sheet (Central Pyrenees). From the structural point of view, the sampled domain constitutes a key area since it is located in the transition between the antiformal stack of the Axial Zone to the West, including non-overturned basement thrust sheets, and the têtes plongeantes domain of the Nogueres unit to the East. The latter comprises three folded thrust sheets, involving Stephanian, Permian and Triassic rocks, whose fronts define several synformal anticlines. Alpine cleavage is generally absent within the têtes plongantes domain but Triassic outcrops located North and West are affected by WNW-ESE-striking, North-dipping cleavage planes. Samples for the study of the anisotropy of magnetic susceptibility were collected from 31 sites, distributed throughout the different structural domains (in the têtes plongeantes domain and in the red beds unconformably overlying the Paleozoic, North and West of the Nogueres unit). Measurements of the magnetic fabric were made at room and low temperature (~77°K) with a KLY-3S susceptibility meter (AGICO, Czech Republic) that combined with a CS-3 apparatus was also used to perform thermomagnetic runs. Mean magnetic susceptibility (Km) in the sampled sites ranges between 35 and 221·10-6 S.I. It is lower in the sandstones (

  7. Natural factors and mining activity bearings on the water quality of the Choapa basin, North Central Chile: insights on the role of mafic volcanic rocks in the buffering of the acid drainage process.

    Science.gov (United States)

    Parra, Amparo; Oyarzún, Jorge; Maturana, Hugo; Kretschmer, Nicole; Meza, Francisco; Oyarzún, Ricardo

    2011-10-01

    This contribution analyzes water chemical data for the Choapa basin, North Central Chile, for the period 1980-2004. The parameters considered are As, Cu Fe, pH, EC, SO₄⁻², Cl⁻¹, and HCO[Formula: see text], from samples taken in nine monitoring stations throughout the basin. Results show rather moderate contents of As, Cu, and Fe, with the exception of the Cuncumén River and the Aucó creek, explained by the influence of the huge porphyry copper deposit of Los Pelambres and by the presence of mining operations, respectively. When compared against results obtained in previous researches at the neighboring Elqui river basin, which host the El Indio Au-Cu-As district, a much reduced grade of pollution is recognized for the Choapa basin. Considering the effect of acid rock drainage (ARD)-related Cu contents on the fine fraction of the sediments of both river basins, the differences recorded are even more striking. Although the Los Pelambres porphyry copper deposit, on the headwaters of the Choapa river basin, is between one and two orders of magnitude bigger than El Indio, stream water and sediments of the former exhibit significantly lower copper contents than those of the latter. A main factor which may explain these results is the smaller degree of H( + )-metasomatism on the host rocks of the Los Pelambres deposit, where mafic andesitic volcanic rocks presenting propylitic hydrothermal alteration are dominant. This fact contrast with the highly altered host rocks of El Indio district, where most of them have lost their potential to neutralize ARD.

  8. First results of repeated Terrestrial Laserscanning monitoring processes at the rock fall area Burgstall/Pasterze Glacier, Hohe Tauern Range, Central Austria

    Science.gov (United States)

    Avian, M.

    2012-04-01

    In July 2007 a large rock fall event at the NW-SE tending ridge of the mountain Mittlerer Burgstall (N47°05´, E12°44´) released appr. 57.000 m3 of rock accumulated at both sides of the ridge partly covering the tongue of Pasterze Glacier, the largest glacier in the Eastern European Alps. First analyses on the event were carried out based on pre- and post event airborne laserscanning as well as photogrammetric data. Ongoing large rock falls in 2008 led to the decision to establish a Terrestrial Laser Scanning (TLS) network to acquire high resolution 3D-surface data. The TLS position is complementary to the existing monitoring network installed in 2006, consisting of ground surface and near surface temperature sensors (projects: ALPCHANGE 2006 - 2011; permaNET 2008-2011; permAfrost 2010 - 2012). In August 2009 first investigations to install a permanent position for TLS to monitor affected rock fall areas were carried out. Unfavourable geometric as well as terrain conditions inhibited the installation of a position to monitor the SW-facing flank of Mittlerer Burgstall mountain. An ideal position to monitor the NE- facing area as well as the S- and E-flank of the nearby Hoher Burgstall was installed in September 2010 at the proglacial area of the Wasserfallwinkelkees glacier. This glacier was once contributing ice masses to the tongue of Pasterze Glacier and is now located about 400 m above the present surface of Pasterze Glacier. Similar to Mittlerer Burgstall, also both flanks of Hoher Burgstall show evidences of imminent larger rock falls which can be hazardous due to the fact that a frequented hiking trail leads to the Oberwalder Hütte alpine hut crosses the lower left part of the E-flank. This hut is a high alpine training centre of the Austrian Alpine club (OEAV) and well visited in during summer. First measurements of both study areas were carried out in September 2010 in mean distances of 600m to the scanning area of Mittlerer Burgstall (MBUG) and 100m to

  9. Source rock

    Directory of Open Access Journals (Sweden)

    Abubakr F. Makky

    2014-03-01

    Full Text Available West Beni Suef Concession is located at the western part of Beni Suef Basin which is a relatively under-explored basin and lies about 150 km south of Cairo. The major goal of this study is to evaluate the source rock by using different techniques as Rock-Eval pyrolysis, Vitrinite reflectance (%Ro, and well log data of some Cretaceous sequences including Abu Roash (E, F and G members, Kharita and Betty formations. The BasinMod 1D program is used in this study to construct the burial history and calculate the levels of thermal maturity of the Fayoum-1X well based on calibration of measured %Ro and Tmax against calculated %Ro model. The calculated Total Organic Carbon (TOC content from well log data compared with the measured TOC from the Rock-Eval pyrolysis in Fayoum-1X well is shown to match against the shale source rock but gives high values against the limestone source rock. For that, a new model is derived from well log data to calculate accurately the TOC content against the limestone source rock in the study area. The organic matter existing in Abu Roash (F member is fair to excellent and capable of generating a significant amount of hydrocarbons (oil prone produced from (mixed type I/II kerogen. The generation potential of kerogen in Abu Roash (E and G members and Betty formations is ranging from poor to fair, and generating hydrocarbons of oil and gas prone (mixed type II/III kerogen. Eventually, kerogen (type III of Kharita Formation has poor to very good generation potential and mainly produces gas. Thermal maturation of the measured %Ro, calculated %Ro model, Tmax and Production index (PI indicates that Abu Roash (F member exciting in the onset of oil generation, whereas Abu Roash (E and G members, Kharita and Betty formations entered the peak of oil generation.

  10. Distribution and biological features of the common pandora, Pagellus erythrinus (Linnaeus, 1758), in the southern Tyrrhenian Sea (Central Mediterranean)

    Science.gov (United States)

    Busalacchi, B.; Bottari, T.; Giordano, D.; Profeta, A.; Rinelli, P.

    2014-12-01

    A synthetic analysis of the distribution, abundance and some biological traits of the common pandora ( Pagellus erythrinus) was performed. Data were gathered in 15 experimental bottom trawl surveys carried out off the southern Tyrrhenian Sea from 1994 to 2008. A total of 2,166 P. erythrinus were found in the investigated area, with a preference for the upper continental shelf (10-100 m). The highest persistence was recorded in the trawl-banned areas. The sex ratio Sr = F/( F + M) ranged between 0.60 and 0.96 (overall 0.78). The size at which 50 % of the individuals were mature was 157 and 170 mm total length for females and males, respectively. The length-weight relationship for all individuals was described by the following parameters: a = 0.016 and b = 2.905. Growth was evaluated (sexes combined) by applying length-based methods; up to eight significant modal components were evidenced. The von Bertalanffy growth parameters for the whole population were estimated at L ∞ = 454 mm, K = 0.08 and t 0 = -2.57. The present results are in agreement with the information available for the other Mediterranean stocks suggesting common biological features.

  11. Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains Central Facility

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, Sally A.; Gaustad, Krista L.; Mlawer, Eli J.; Long, Charles N.; Delamere, Jennifer

    2011-09-01

    We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM) facility at the Southern Great Plains (SGP) site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs), four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated) can be identified. A normalized difference vegetation index (NDVI) is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs) and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

  12. Southern and Central California Chaparral and Oak Woodlands Ecoregion: Chapter 19 in Status and trends of land change in the Western United States--1973 to 2000

    Science.gov (United States)

    Napton, Darrell E.

    2012-01-01

    The Southern and Central California Chaparral and Oak Woodlands Ecoregion, which covers approximately 102,110 km2 (39,425 mi2), is characterized by a Mediterranean climate with cool, moist winters and hot, dry summers (Omernik, 1987; U.S. Environmental Protection Agency, 1997). Natural vegetation includes chaparral (for example, manzanita, Arctostaphylos spp.) and oak (Quercus spp.) woodlands with extensive grassland and shrubland cover. The low mountains and foothills of the ecoregion border or parallel the Pacific Ocean from Mexico to Point Reyes, California, and continue inland surrounding the Central California Valley Ecoregion (fig. 1). These mountains and hills are interrupted by limited areas of flat land generally used for development or agriculture. The largest developed area in the ecoregion is the Los Angeles Basin, followed by the San Francisco Bay area and the San Diego metropolitan area (fig. 1). The largest agricultural area is the Salinas River valley south of Monterey, California. Most of the ecoregion consists of rangelands classified as grassland/ shrubland and forest land covers (figs. 1,2).

  13. On the relationship between the climate variability in middle-low latitudes of the Southern Hemisphere and central Antarctica over the past 350 years

    Science.gov (United States)

    Ekaykin, A. A.; Kozachek, A. V.; Lipenkov, V. Ya.; Shibaev, Yu. A.; Vaikmae, R.

    2012-04-01

    Based on data of geochemical and glaciological investigations in snow pits and on snow cores, stack series of air temperature and snow accumulation rate variability in central Antarctica (Vostok station vicinities) have been obtained for the last 350 years. It has been shown that these parameters varied quasi-periodically with the wavelength of 30-60 years superimposed on the slight positive trend. The correlation of these series with the circulation indices of Southern Hemisphere has allowed to establish some regularities in the climatic variability of low to high latitudes. We suggest that the central Antarctic climate is mainly governed by the type of circulation in the SH: under conditions of zonal circulation negative anomalies of temperature and precipitation rate are observed, while during meridional circulation the sign of anomaly is opposite. It has been noted that in the 1970s the sign of the relationship between many climatic parameters has changed that is likely related to the rearrangement of the climatic system of the SH. It has been also established that during the past 350 years such climate shifts have happened at least 6 times. This work was supported by Russian Foundation for Basic Research grant 10-05-93106.

  14. Regional Climate Zone Modeling of a Commercial Absorption Heat Pump Hot Water Heater Part 1: Southern and South Central Climate Zones

    Energy Technology Data Exchange (ETDEWEB)

    Geoghegan, Patrick J [ORNL; Shen, Bo [ORNL; Keinath, Christopher M. [Stone Mountain Technologies, Inc., Johnson City; Garrabrant, Michael A. [Stone Mountain Technologies, Inc., Johnson City

    2016-01-01

    Commercial hot water heating accounts for approximately 0.78 Quads of primary energy use with 0.44 Quads of this amount from natural gas fired heaters. An ammonia-water based commercial absorption system, if fully deployed, could achieve a high level of savings, much higher than would be possible by conversion to the high efficiency nonheat-pump gas fired alternatives. In comparison with air source electric heat pumps, the absorption system is able to maintain higher coefficients of performance in colder climates. The ammonia-water system also has the advantage of zero Ozone Depletion Potential and low Global Warming Potential. A thermodynamic model of a single effect ammonia-water absorption system for commercial space and water heating was developed, and its performance was investigated for a range of ambient and return water temperatures. This allowed for the development of a performance map which was then used in a building energy modeling software. Modeling of two commercial water heating systems was performed; one using an absorption heat pump and another using a condensing gas storage system. The energy and financial savings were investigated for a range of locations and climate zones in the southern and south central United States. A follow up paper will analyze northern and north/central regions. Results showed that the system using an absorption heat pump offers significant savings.

  15. Geochemical and isotopic variations in the calc-alkaline rocks of Aeolian arc, southern Tyrrhenian Sea, Italy: constraints on magma genesis

    Science.gov (United States)

    Francalanci, L.; Taylor, S. R.; McCulloch, M. T.; Woodhead, J. D.

    1993-03-01

    New geochemical and isotopic data are reported for calc-alkaline (CA) volcanics of the Aeolian arc. Three main groups are recognized: the Alicudi and Filicudi volcanics in the western part of the arc; the Panarea, Salina and Lipari (henceforth termed PSL) volcanics in the central part of the arc and the Stromboli suite which makes up the eastern part of the arc. Each group is characterized by distinctive isotopic ratios and incompatible element contents and ratios. 87Sr/86Sr values (0.70352 0.70538) increase from west to northeast, and are well correlated with 143Nd/144Nd (ɛNd from +4.8 to -1.5). Pb isotope ratios are fairly high (6/4=19.15 19.54; 7/4=15.61 15.71; 8/4=38.97 39.36), with a general increase of 7/4 and 8/4 values from Alicudi to PSL islands and Stromboli. LILE contents and some incompatible element ratios (e.g. Ba/La, La/Nb, Zr/Nb, Rb/Sr) increase from the western to the central part of the arc, whereas HFSE and REE abundances decrease. Opposite variations are often observed in the volcanics toward the north-east from PSL islands. To account for these features and the decoupling observed between isotopic compositions and incompatible element abundances and ratios, it is suggested that a mantle source with affinities to the MORB source is “metasomatized” by slab-derived, crustal components. The proportion of crustal material entrained in the mantle source increases from Alicudi to Stromboli, according to the Sr and Nd isotope variations. It is also proposed that slab derived hydrous fluids play an important role, but which is variable in different sectors of the arc. This is attributed to the metasomatizing agent having variable fluid/melt ratios, reflecting different types of mass transfer from the subducted contaminant (probably pelagic sediments) to the mantle wedge. Thus, it is suggested that the slab derived end-member has a high hydrous fluid/melt ratio in the PSL mantle source and a correspondingly lower ratio in the Alicudi and Stromboli

  16. Scattering from Rock and Rock Outcrops

    Science.gov (United States)

    2015-09-30

    Scattering from Rock and Rock Outcrops Derek R. Olson The Pennsylvania State University Applied Research Laboratory, P.O. Box 30 State...In terms of target detection and classification, scattering from exposed rock on the seafloor, (i.e., individual rocks and rock outcrops) presents...levels, and other statistical measures of acoustic scattering from rocks and rock outcrops is therefore critical. Unfortunately (and curiously

  17. Impacts of land-use and soil properties on groundwater quality in the hard rock aquifer of an irrigated catchment: the Berambadi (Southern India)

    Science.gov (United States)

    Buvaneshwari, Sriramulu; Riotte, Jean; Ruiz, Laurent; Sekhar, Muddu; Sharma, Amit Kumar; Duprey, Jean Louis; Audry, Stephane; Braun, Jean Jacques; Mohan Kumar, Mandalagiri S.

    2017-04-01

    Irrigated agriculture has large impacts on groundwater resources, both in terms of quantity and quality: when combined with intensive chemical fertilizer application, it can lead to progressive groundwater salinization. Mapping the spatial heterogeneity of groundwater quality is not only essential for assessing the impacts of different types of agricultural systems but also for identifying hotspots of water quality degradation that are posing a risk to human and ecosystem health. In peninsular India the development of minor irrigation led to high density of borewells which constitute an ideal situation for studying the heterogeneity of groundwater quality. The annual groundwater abstraction reaches 400 km3, which leads to depletion of the resource and degradation of water quality. In the agricultural Berambadi catchment (84km2, Southern India, part of the environmental observatory BVET/ Kabini CZO) the groundwater table level and chemistry are monitored in 200 tube wells. We recently demonstrated that in this watershed, irrigation history and groundwater depletion can lead to hot spots of NO3 concentration in groundwater, up to 360 ppm (Buvaneshwari et al., 2017). Here we focus on the respective roles of evapotranspiration, groundwater recycling and chemical fertilizer application on chlorine concentration [Cl] in groundwater. Groundwater [Cl] in Berambadi spans over two orders of magnitude with hotspots up to 380 ppm. Increase in groundwater [Cl] results from evapotranspiration and recycling, that concentrates the rain Cl inputs ("Natural [Cl]") and/or from KCl fertilization ("Anthropogenic [Cl]"). To quantify the origin of Cl in each tube well, we used a novel method based on (1) a reference element, sodium, originating only from atmosphere and Na-plagioclase weathering and (2) data from a nearby pristine site, the Mule Hole forested watershed (Riotte et al., 2014). In the forested watershed, the ranges of Cl concentration and Na/Cl molar ratio are 9-23 ppm and 2

  18. Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains central facility

    Directory of Open Access Journals (Sweden)

    J. Delamere

    2011-09-01

    Full Text Available We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM facility at the Southern Great Plains (SGP site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs, four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated can be identified. A normalized difference vegetation index (NDVI is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

  19. Timing of Deformation in the Central Metasedimentary Belt Boundary Thrust Zone (CMBbtz), southern Ontario, Canada, from Electron Microprobe Dating of Monazite

    Science.gov (United States)

    Markley, M. J.; Dunn, S. R.; Peck, W. H.; Jercinovic, M. J.; Williams, M. L.

    2015-12-01

    In the Grenville Province of Southern Ontario, the Central Metasedimentary Belt boundary thrust zone (CMBbtz) is a crustal-scale tectonic boundary between the older, granulite-facies Central Gneiss Belt to the NW and the younger, amphibolite-facies Central Metasedimentary Belt to the SE. Although there are a range of tectonic models for the CMBbtz, most workers agree it is a major tectonic boundary that accommodated ductile thrusting and crustal shortening during the Ottawan phase of the Grenville Orogeny (~1080-1020 Ma). Some studies suggest that ductile thrusting in the CMBbtz was roughly synchronous with synorogenic extensional collapse below an orogenic lid. Previous geochronological studies also provide evidence of earlier deformation and/or metamorphic events in the CMBbtz, although the relation between deformation in the CMBbtz to the Elzeviran (~1230 Ma) and Shawinigan (~1180 Ma) orogenies is unclear. Our study is the first to report in situ electron microprobe monazite (mnz) dates from amphibolite-grade ortho- and para-gneisses of the CMBbtz. Our results are broadly consistent with other chronometers. We present dates from 132 age-domains within 83 mnz grains in 14 samples. Although our data provide strong evidence for deformation and metamorphism along the length of the CMBbtz during the Ottawan (1080-1020 Ma), we also report two other clusters of ages: 1140-1110 Ma and 1230-1170 Ma. The latter cluster falls between the widely accepted ranges for the Elzeviran and Shawinigan orogenies. In addition, some individual outcrops, particularly those in Killaloe and Minden, show mnz ages spanning over 200 m.y., and the setting and compositions of individual monazite domains allow us to link mnz growth to episodes of garnet growth during multiple events. Together these data indicate an unexpectedly continuous and long-lived period of deformation and metamorphism in the CMBbtz.

  20. Isotope/Air Temperature Relationships From Snow-Firn Core Time Series at the Northern and Southern Periphery of the Central Asian Mountain System

    Science.gov (United States)

    Joswiak, D.; Aizen, E.; Aizen, V.

    2004-12-01

    Spatial variability of stable isotope records from snow pits and snow-firn cores to depths of 21 m are used to examine isotope/air temperature relationships for three locations at the northern and southern periphery of the central Asian mountain system: the West Belukha glaciated Plateau in the Altai, the head of Inylchek Glacier in central Tien Shan, and the Bomi glacierized massif in southeastern Tibet. The 18O records show pronounced maxima and minima, interpreted to represent annual accumulation layers and verified with stratigraphic profiles. Mean δ 18O from the Altai core is -13.6\\permil, -16.0\\permil for the Tien Shan core, and -16.3\\permil for the southeastern Tibet core. Mean annual ranges of the δ 18O signal vary from 9.5\\permil in the Altai core, to 16.6\\permil in the Tien Shan core, and 10.1\\permil in the southeastern Tibet core. Mean deuterium excess varied from 10.9\\permil for the Altai core to 23.0\\permil for the Tien Shan core. Isotope/air temperature relationships are examined for variability of regression lines (slope and intercept) associated with internal and external moisture sources, which vary seasonally. Positive regression line slopes are observed for the Tien Shan and Altai Mountains, with minimum δ 18O values associated with minimum winter temperatures. A negative regression line slope is observed at southeastern Tibet, with minimum δ 18O values associated with heavy amounts of isotopically depleted precipitation occurring during the summer months at this location. These isotope records will aid in providing information important to the forecasting of global climate change linking regional responses with atmospheric circulation patterns from the North Atlantic to Pacific and Indian Oceans. These techniques can be applied to recently recovered deep (surface to bottom) ice cores from the central Tien Shan and Altai Mountains.

  1. Intellektuaalne rock

    Index Scriptorium Estoniae

    2007-01-01

    Briti laulja-helilooja ja näitleja Toyah Willcox ning Bill Rieflin ansamblist R.E.M. ja Pat Mastelotto King Krimsonist esinevad koos ansamblitega The Humans ja Tuner 25. okt. Tallinnas Rock Cafés ja 27. okt Tartu Jaani kirikus

  2. The Mass Elevation Effect of the Central Andes and Its Implications for the Southern Hemisphere's Highest Treeline

    Directory of Open Access Journals (Sweden)

    Wenhui He

    2016-05-01

    Full Text Available One of the highest treelines in the world is at 4810 m above sea level on the Sajama Volcano in the central Andes. The climatological cause of that exceptionally high treeline position is still unclear. Although it has been suggested that the mass elevation effect (MEE explains the upward shift of treelines in the Altiplano region, the magnitude of MEE has not yet been quantified for that region. This paper defines MEE as the air temperature difference in summer at the same elevation between the inner mountains/plateaus (Altiplano and the free atmosphere above the adjacent lowlands of the Andean Cordillera. The Altiplano air temperature was obtained from the Global Historical Climatology Network-Monthly temperature database, and the air temperature above the adjacent lowlands was interpolated based on the National Center for Environmental Prediction/National Center for Atmospheric Research Reanalysis 1 data set. We analyzed the mean air temperature differences for January, July, and the warm months from October to April. The air temperature was mostly higher on the Altiplano than over the neighboring lowlands at the same altitude. The air temperature difference increased from the outer Andean east-facing slope to the interior of the Altiplano in summer, and it increased from high latitudes to low latitudes in winter. The mean air temperature in the Altiplano in summer is approximately 5 K higher than it is above the adjacent lowlands at the same mean elevation, averaging about 3700 m above sea level. This upward shift of isotherms in the inner part of the Cordillera enables the treeline to climb to 4810 m, with shrub-size trees reaching even higher. Therefore, the MEE explains the occurrence of one of the world’s highest treelines in the central Andes.

  3. Igneous Rocks

    Science.gov (United States)

    Doe, Bruce R.

    “Igneous Rocks was written for undergraduate geology majors who have had a year of college-level chemistry and a course in mineralogy … and for beginning graduate students. Geologists working in industry, government, or academia should find this text useful as a guide to the technical literature up to 1981 and as an overview of topics with which they have not worked but which may have unanticipated pertinence to their own projects.” So starts the preface to this textbook.As one who works part time in research on igneous rocks, especially as they relate to mineral deposits, I have been looking for such a book with this avowed purpose in a field that has a choking richness of evolving terminology and a bewildering volume of interdisciplinary literature. In addition to the standard topics of igneous petrology, the book contains a chapter on the role of igneous activity in the genesis of mineral deposits, its value to geothermal energy, and the potential of igneous rocks as an environment for nuclear waste disposal. These topics are presented rather apologetically in the preface, but the author is to be applauded for including this chapter. The apology shows just how new these interests are to petrology. Recognition is finally coming that, for example, mineral deposits are not “sports of nature,” a view held even by many economic geologists as recently as the early 1960's; instead they are perfectly ordinary geochemical features formed by perfectly ordinary geologic processes. In fact, the mineral deposits and their attendant alteration zones probably have as much to tell us about igneous rocks as the igneous rocks have to tell us about mineral deposits.

  4. Satellite-measured interannual variability of turbid river plumes off central-southern Chile: Spatial patterns and the influence of climate variability

    Science.gov (United States)

    Saldías, Gonzalo S.; Largier, John L.; Mendes, Renato; Pérez-Santos, Iván; Vargas, Cristian A.; Sobarzo, Marcus

    2016-08-01

    Ocean color imagery from MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the Aqua platform is used to characterize the interannual variability of turbid river plumes off central-southern Chile. Emphasis is placed on the influence of climate fluctuations, namely El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and the Antarctic Oscillation (AAO). Additional satellite data on wind, boat-based hydrographic profiles, and regional climate indices are used to identify the influence of climate variability on the generation of anomalous turbid river plumes. The evolution of salinity at a coastal station on the 90 m isobath between the Itata and Biobío Rivers shows a freshwater surface layer with salinity < 32.5 and 5-10 m thick during major plume events in 2002, 2005 and 2006. Surface salinity minima are correlated with peaks in turbidy from the normalized water leaving radiance at 555 nm (nLw(555)), both representing turbid river plumes. EOF analysis reveals that major turbid plume events occurred primarily during warm phases of the ENSO and PDO, and negative phases of the AAO, when storm tracks are further north. Anomalously large turbid plumes extend long distances offshore (∼ 70-80 km), and individual plumes coalesce into a continuous plume along the coast that covers the entire continental shelf. Season-specific correlation analyses reveal an increased influence of the AAO on river plumes south of Punta Lavapié in spring-summer (negative correlation). North of this major cape, ENSO and PDO indices have a dominant influence on plumes with positive correlations with the nLw(555) signal in winter (and negative in summer). We discuss the biogeochemical implications of plume events and the importance of long-term and high-resolution ocean color observations for studying the temporal evolution of river plumes.

  5. Risk mapping of Rinderpest sero-prevalence in Central and Southern Somalia based on spatial and network risk factors

    Directory of Open Access Journals (Sweden)

    Aden Hussein H

    2010-04-01

    Full Text Available Abstract Background In contrast to most pastoral systems, the Somali livestock production system is oriented towards domestic trade and export with seasonal movement patterns of herds/flocks in search of water and pasture and towards export points. Data from a rinderpest survey and other data sources have been integrated to explore the topology of a contact network of cattle herds based on a spatial proximity criterion and other attributes related to cattle herd dynamics. The objective of the study is to integrate spatial mobility and other attributes with GIS and network approaches in order to develop a predictive spatial model of presence of rinderpest. Results A spatial logistic regression model was fitted using data for 562 point locations. It includes three statistically significant continuous-scale variables that increase the risk of rinderpest: home range radius, herd density and clustering coefficient of the node of the network whose link was established if the sum of the home ranges of every pair of nodes was equal or greater than the shortest distance between the points. The sensitivity of the model is 85.1% and the specificity 84.6%, correctly classifying 84.7% of the observations. The spatial autocorrelation not accounted for by the model is negligible and visual assessment of a semivariogram of the residuals indicated that there was no undue amount of spatial autocorrelation. The predictive model was applied to a set of 6176 point locations covering the study area. Areas at high risk of having serological evidence of rinderpest are located mainly in the coastal districts of Lower and Middle Juba, the coastal area of Lower Shabele and in the regions of Middle Shabele and Bay. There are also isolated spots of high risk along the border with Kenya and the southern area of the border with Ethiopia. Conclusions The identification of point locations and areas with high risk of presence of rinderpest and their spatial visualization as a

  6. Late Neogene oroclinal bending in the central Taurides: A record of terminal eastward subduction in southern Turkey?

    Science.gov (United States)

    Koç, Ayten; van Hinsbergen, Douwe J. J.; Kaymakci, Nuretdin; Langereis, Cornelis G.

    2016-01-01

    The Tauride fold-thrusts belt formed during ∼S-N convergence between Africa and Eurasia since Cretaceous time. The western end of the central Taurides strike NW-SE, highly obliquely to the overall convergence direction, and connect to the NE-SW Beydağları-Lycian Nappe flank of the western Taurides, forming the so-called 'Isparta Angle'. In Neogene time, the western and central Taurides and the inner part of the Isparta Angle became overlain by Neogene sedimentary basins including Manavgat, Köprüçay and Aksu, characterized by marine clastics and carbonates. The eastern limb of the Isparta Angle experienced multidirectional Miocene to Present extension, whereas E-W shortening affected the marine sedimentary basins in the heart of the Isparta Angle. To quantitatively reconstruct the Neogene kinematic evolution of the Taurides, towards restoring the subduction system accommodating Africa-Eurasia convergence, we paleomagnetically assess if and when vertical axis rotations affected the Manavgat, Köprüçay, and Aksu basins in Early Miocene to Pliocene times. We show that the northern Köprüçay Basin rotated ∼20-30° clockwise, the Manavgat Basin underwent ∼25-35° counterclockwise rotation, and the Aksu Basin underwent no rotation since the Early-Middle Miocene. It was previously shown that the Beydağları region underwent a post-Middle Miocene ∼20° counterclockwise rotation. These results show that the prominent oroclinal salient geometry of the western Taurides thus acquired, at least in part, since Miocene times, that the Köprüçay Basin rotated relative to the Aksu Basin along the Aksu thrust, and that the Beydağları platform rotated relative to the Aksu Basin along the Bucak thrust, which must have both been active until Late Neogene time. This synchronous E-W shortening in the heart of the Isparta Angle, and multidirectional extension in its eastern limb may be explained by relative westward retreat of an eastward dipping subducting Antalya

  7. Fabric Controls on the Failure Mode of Strongly Deformed Metamorphic Rocks with Multiple Anisotropies

    Science.gov (United States)

    Agliardi, F.; Zanchetta, S.; Crosta, G. B.; Barberini, V.; Fusi, N.; De Ponti, E.

    2012-12-01

    Classical models of rock fracture in geodynamics, seismology, and rock engineering are built on basic modes of failure (e.g. tensile, shear, leaning) in isotropic homogeneous material. Nevertheless, the strength, deformability and mode of failure of anisotropic, often folded metamorphic rocks forming significant parts of both the shallow and deep Earth's crust strongly depend on rock mineralogy and fabric. Although a large body of literature exists on the effects of single planar anisotropy on rock failure (e.g. strength dependencies and slip tendency), fabric controls on the behavior of rocks which underwent severe ductile deformation (e.g. crenulation folding) are still poorly understood and further knowledge is required to improve existing models. In this perspective, we studied experimentally the mechanical behaviour of gneisses (Monte Canale unit) and phyllites (Ambria Unit) from the Italian Central Alps and Southern Alps. Rock petrography and fabric were characterised through standard optical microscopy and XRD techniques. About 60 gneiss samples and 40 phyllite samples from available drill cores were prepared and tested under uniaxial and triaxial (multistage) compression, and indirect tension (Brazilian) tests. Laboratory tests allowed reconstructing the stress-strain behaviour and the main mechanical properties of intact rock, as well as observing the fracture patterns and estimating fracture energies of tested samples. Rock samples revealed low and scattered values of unconfined compressive strength (UCS) and Young's modulus. Rock samples broke according to four failure modes, from the well-known shear failure along foliation to the development of centimetre-scale brittle shear zones, both at low and high confining pressure. Moreover, no clear dependence of rock strength on the foliation direction could be identified. Fracture patterns were thus further investigated and quantified in 3D through X-ray Computed Tomography imaging, performed at different

  8. White Rock

    Science.gov (United States)

    2002-01-01

    (Released 19 April 2002) The Science 'White Rock' is the unofficial name for this unusual landform which was first observed during the Mariner 9 mission in the early 1970's. As later analysis of additional data sets would show, White Rock is neither white nor dense rock. Its apparent brightness arises from the fact that the material surrounding it is so dark. Images from the Mars Global Surveyor MOC camera revealed dark sand dunes surrounding White Rock and on the floor of the troughs within it. Some of these dunes are just apparent in the THEMIS image. Although there was speculation that the material composing White Rock could be salts from an ancient dry lakebed, spectral data from the MGS TES instrument did not support this claim. Instead, the White Rock deposit may be the erosional remnant of a previously more continuous occurrence of air fall sediments, either volcanic ash or windblown dust. The THEMIS image offers new evidence for the idea that the original deposit covered a larger area. Approximately 10 kilometers to the southeast of the main deposit are some tiny knobs of similarly bright material preserved on the floor of a small crater. Given that the eolian erosion of the main White Rock deposit has produced isolated knobs at its edges, it is reasonable to suspect that the more distant outliers are the remnants of a once continuous deposit that stretched at least to this location. The fact that so little remains of the larger deposit suggests that the material is very easily eroded and simply blows away. The Story Fingers of hard, white rock seem to jut out like icy daggers across a moody Martian surface, but appearances can be deceiving. These bright, jagged features are neither white, nor icy, nor even hard and rocky! So what are they, and why are they so different from the surrounding terrain? Scientists know that you can't always trust what your eyes see alone. You have to use other kinds of science instruments to measure things that our eyes can

  9. Flight phenologies of the southeastern Ips species (Coleoptera: Curculionidae: Scolytinae) and some associated Coleoptera in central and southern Louisiana.

    Science.gov (United States)

    Schoeller, Erich N; Allison, Jeremy D

    2013-12-01

    A year-long flight phenology study was undertaken from 15 July 2009 to 7 July 2010 in central and southeastern Louisiana to estimate the temporal flight patterns of the three southeastern Ips species: Ips grandicollis (Eichhoff), Ips avulsus (Eichhoff), and Ips calligraphus (Germar) (Coleoptera: Curculionidae: Scolytinae) as well as some of their predatory and phloem-feeding coleopteran associates. The southeastern Ips species play important roles as decomposers in forest ecosystems, but can cause ecological and economic damage during epidemic population phases. In total, 282,761 individuals of the three southeastern Ips species were collected using Ips pheromone-baited multiple funnel traps during the study period. Two major Ips activity peaks were observed during 16 September to 7 October of 2009 and 24 March to 15 April of 2010. In total, 9,139 associated Coleoptera were also collected. Greater than 95% of the total number of associated Coleoptera collected were represented by histerids from the genus Platysoma (4,487; 49.1% of total), the trogossitid Temnoscheila virescens (F.) (2,107; 23.1%), cerambycids from the genus Monochamus (1,013; 11.1%), and Acanthocinus obsoletus (Olivier) (743; 8.1%), and the clerid Thanasimus dubius (F.) (477; 5.2%). Results showed that the associates fell into four temporal groups: the winter and spring active species T. dubius; the spring active species Rhagium inquisitor (L.) and histerids from the genus Platysoma; the spring and summer active species T. virescens, Buprestis lineata F., and Monochamus carolinensis (Olivier); and the summer through fall active species A. obsoletus and Monochamus titillator (F.).

  10. Geochemical, petrographic and physical characterizations and associated alterations of the volcanic rocks of the Romanesque San Nicola Church (Ottana, central Sardinia, Italy)

    Science.gov (United States)

    Columbu, Stefano; Palomba, Marcella; Sitzia, Fabio

    2015-04-01

    In this research, the volcanic rocks belonging to the Sardinia Oligo-Miocene volcanic cycle (32 - 11 Ma) and building up the structure of the San Nicola church, one of the most representative churches of the Romanesque architecture, were studied. These stones were widely used in medieval architecture for the excellent workability, but they present some disadvantages, since they are greatly affected by alteration phenomena. The main objectives of this research are i) to focus the mineral, chemical and petrographic compositions of the San Nicola stones, ii) the chemical and physical alteration processes affecting these materials, and iii) to establish the exactly provenance of the volcanic rocks. Furthermore, a comparative study between the rocks from the ancient quarries and those forming the structure of the church was performed. In the ancient quarries, where presumably a more advanced alteration occurs due to the vertical alteration gradient, different facies of the same volcanic lithology, characterized by macroscopical evidences of chemical-physical degradation degree, were sampled. Petrographic, geochemical (both major elements that the traces) and physical-mechanical features of the collected samples were determined to highlight the compositional differences (density, porosity, water-absorption kinetics, mechanical resistance) as a function of the different alteration degree. Moreover, chemical-mineralogical analysis of the sample surfaces from the church, was performed, to highlight possible presence and nature of secondary newly-formed phases (e.g., salt efflorescence). Several methodologies were applied to carry out physical-chemical and petrographic analysis: X-Ray fluorescence (XRF) and Inductively Coupled Mass Spectrometry (ICP-MS), X-Ray Diffractometry (XRD) for chemical and mineral composition; Optical and Scanning Electron Microscopy (SEM) for textures, mineral assemblages and microstructures studies; He-picnometry, water-absorption and mechanical

  11. Paleomagnetic and rock-magnetic study on volcanic units of the Valsequillo Basin: implications for early human occupation in central Mexico

    Science.gov (United States)

    Goguitchaichvili, Avto; Pozzo, Ana Lillian Martin-Del; Rocha-Fernandez, Jose Luis; Urrutia-Fucugauchi, Jaime; Soler-Arechalde, Ana Maria

    2009-01-01

    Alleged human and animal footprints were found within the upper bedding surfaces of the Xalnene volcanic ash layer that outcrops in the Valsequillo Basin, south of Puebla, Mexico (Gonzalez et al, 2005). The ash has been dated at 40 ka by optically stimulated luminescence analysis, thereby providing new evidence that America was colonized earlier than the Clovis culture (about 13.5 Ma). We carried out paleomagnetic and rock magnetic analysis on 18 Xalnene ash block and core samples collected at two distinct localities and 19 standard paleomagnetic cores belonging to nearby monogenetic volcanoes. Our data provide evidence that both the volcanic lava flow and Xalnene ash were emplaced during the Laschamp geomagnetic event spanning from about 45 to 39 ka.

  12. High-resolution 40Ar/39Ar geochronology of volcanic rocks from the Siebengebirge (Central Germany)—Implications for eruption timescales and petrogenetic evolution of intraplate volcanic fields

    Science.gov (United States)

    Przybyla, Thomas; Pfänder, Jörg A.; Münker, Carsten; Kolb, Melanie; Becker, Maike; Hamacher, Uli

    2017-11-01

    A key parameter in understanding mantle dynamics beneath continents is the temporal evolution of intraplate volcanism in response to lithospheric thinning and asthenospheric uplift. To contribute to a better understanding of how intraplate volcanic fields evolve through time, we present a high precision 40Ar/39Ar age dataset for volcanic rocks from the Siebengebirge volcanic field (SVF) from central Germany, one of the best studied and compositionally most diverse intraplate volcanic fields of the Cenozoic Central European Volcanic Province (CEVP). Petrological and geochemical investigations suggest that the formation of the different rock types that occur in the SVF can be explained by a combination of assimilation and fractional crystallisation processes, starting from at least two different parental magmas with different levels of silica saturation (alkali basaltic and basanitic), and originating from different mantle sources. These evolved along two differentiation trends to latites and trachytes, and to tephrites and tephriphonolites, respectively. In contrast to their petrogenesis, the temporal evolution of the different SVF suites is poorly constrained. Previous K/Ar ages suggested a time of formation between about 28 and 19 Ma for the mafic rocks, and of about 27 to 24 Ma for the differentiated rocks. Our results confirm at high precision that the differentiated lithologies of both alkaline suites (40Ar/39Ar ages from 25.3 ± 0.2 Ma to 25.9 ± 0.3 Ma) erupted contemporaneously within a very short time period of 0.6 Ma, whereas the eruption of mafic rocks (basanites) lasted at least 8 Ma (40Ar/39Ar ages from 22.2 ± 0.2 Ma to 29.5 ± 0.3 Ma). This implies that felsic magmatism in the central SVF was likely a single event, possibly triggered by an intense phase of rifting, and that ongoing melting and eruption of mostly undifferentiated mafic lavas dominate the > 8 Ma long magmatic history of this region. Among the mafic lavas, most basanites and tephrites

  13. Mesozoic magmatism and timing of epigenetic Pb-Zn-Ag mineralization in the western Fortymile mining district, east-central Alaska: Zircon U-Pb geochronology, whole-rock geochemistry, and Pb isotopes

    Science.gov (United States)

    Dusel-Bacon, Cynthia; Aleinkoff, J.N.; Day, W.C.; Mortensen, J.K.

    2015-01-01

    The Mesozoic magmatic history of the North American margin records the evolution from a more segmented assemblage of parautochthonous and allochthonous terranes to the more cohesive northern Cordilleran orogenic belt. We characterize the setting of magmatism, tectonism, and epigenetic mineralization in the western Fortymile mining district, east-central Alaska, where parautochthonous and allochthonous Paleozoic tectonic assemblages are juxtaposed, using sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon geochronology, whole-rock geochemistry, and feldspar Pb isotopes of Mesozoic intrusions and spatially associated mineral prospects. New SHRIMP U-Pb zircon ages and published U-Pb and 40Ar/39Ar ages indicate four episodes of plutonism in the western Fortymile district: Late Triassic (216-208 Ma), Early Jurassic (199-181 Ma), mid-Cretaceous (112-94 Ma), and Late Cretaceous (70-66 Ma). All age groups have calc-alkalic arc compositions that became more evolved through time. Pb isotope compositions of feldspars from Late Triassic, Early Jurassic, and Late Cretaceous igneous rocks similarly became more radiogenic with time and are consistent with the magmas being mantle derived but extensively contaminated by upper crustal components with evolving Pb isotopic compositions. Feldspar Pb isotopes from mid-Cretaceous rocks have isotopic ratios that indicate magma derivation from upper crustal sources, probably thickened mid-Paleozoic basement. The origin of the mantle component in Late Cretaceous granitoids suggested by Pb isotopic ratios is uncertain, but we propose that it reflects asthenospheric upwelling following slab breakoff and sinking of an inactive inner subduction zone that delivered the previously accreted Wrangellia composite terrane to the North American continental margin, after the outer Farallon subduction zone was established.

  14. Geology and fuel resources of the southern part of the San Juan Basin, New Mexico. Part 1, The coal field from Gallup eastward toward Mount Taylor, with a measured section of pre-Dakota(?) rocks near Navajo Church

    Science.gov (United States)

    Sears, Julian D.

    1934-01-01

    The report describes the geology and coal deposits of the southwestern part of the San Juan Basin, N.Mex. The field lies northeast of the town of Gallup, on the Atchison, Topeka & Santa Fe Railway, and is an irregular tract of about 630 square miles in central and west-central McKinley County; it includes the southeast corner of the Navajo Indian Reservation. Settlement is confined to the white families at a few trading posts and the Indian agency at Crown Point and to scattered Navajo Indians. The land forms, drainage, vegetation, and climate are those typical of the highland in the semiarid Southwest.The investigation disclosed complicated relations of the Mancos shale and the Mesaverde formation, of Upper Cretaceous age, and a marked variation in the stratigraphic boundary between them. At the western edge of the field, as in the adjoining Gallup coal district, the Mancos consists of about 725 feet of marine shale almost wholly of Benton (lower Colorado) age. It is overlain by about 1,800 feet of chiefly estuarine and fluviatile deposits that represent the lower part of the Mesaverde formation. In ascending order the Mesaverde here consists of the Gallup sandstone member (which includes local lenses of valuable coal), the Dilco coal member, the Bartlett barren member, the Gibson coal member, and the Allison barren member. Eastward through the field the outcrops extend obliquely across the trend of old shore lines out into the ancient basin of marine deposition, and some of the beds consequently show a progressive lateral change into rocks of littoral and marine types. The Gallup sandstone member is in part replaced by marine shale of the Mancos. The upper part of the Dilco coal member is replaced by the Dalton sandstone member, and still farther east the bottom of the Dalton and the top of the remaining Dilco are replaced by the Mulatto tongue of the Mancos shale. The Bartlett barren member becomes coal-bearing and thus merges with the Gibson. The Gibson coal

  15. Timing and conditions of metamorphism and melt crystallization in Greater Himalayan rocks, eastern and central Bhutan: insight from U-Pb zircon and monazite geochronology and trace-element analyses

    Science.gov (United States)

    Zeiger, K.; Gordon, S. M.; Long, S. P.; Kylander-Clark, A. R. C.; Agustsson, K.; Penfold, M.

    2015-05-01

    Within the eastern Himalaya in central and eastern Bhutan, Greater Himalayan (GH) rocks are interpreted to have been thickened by the Kakhtang thrust (KT). In order to understand the metamorphic and exhumation history of the GH and to evaluate the structural significance of the KT, zircon and monazite from twenty samples were analyzed by laser-ablation split-stream ICPMS. In eastern Bhutan, zircon and monazite from samples collected in the KT hanging wall revealed ca. 36-28 Ma metamorphism. Subsequently, the initiation of melt crystallization shows a trend with structural distance above the KT, with early melt crystallization (ca. 27 Ma) in the structurally highest samples and younger melt crystallization (ca. 16 Ma) for leucosomes within the KT zone. Melt crystallization was protracted and continued until ca. 14-13 Ma in both the KT hanging wall and the footwall. In comparison, in central Bhutan, two leucosomes revealed extended melt crystallization from ca. 31 to 19 Ma. The youngest zircon dates from samples exposed structurally above and below the KT are similar, indicating that the KT was not as significant of a structure as other fault systems to which it has been correlated. However, the younging trend in the initiation of melt crystallization with decreasing structural distance above the KT argues that progressive underplating of ductile material assisted in the initial emplacement of the GH unit in central and eastern Bhutan. The KT likely represents a minor shear zone that aided in this underplating process.

  16. Mesoscale variability and nutrient-phytoplankton distributions off central-southern Chile during the upwelling season: The influence of mesoscale eddies

    Science.gov (United States)

    Morales, Carmen E.; Hormazabal, Samuel; Correa-Ramirez, Marco; Pizarro, Oscar; Silva, Nelson; Fernandez, Camila; Anabalón, Valeria; Torreblanca, M. Loreto

    2012-10-01

    Mesoscale features are recurrently found in the Coastal Transition Zone (CTZ) off central-southern Chile (∼35-40°S), a region characterized by seasonal wind-driven coastal upwelling. In this study, oceanographic data from two consecutive cruises carried out during the upwelling season (January 2009) were combined with satellite time series data in order to characterize the structure and evolution of mesoscale eddies and to explore their influence on phytoplankton structure and nutrient distribution, in the context of organic carbon exchanges between the coastal upwelling zone and the CTZ. Two coastally-generated, contiguous mesoscale eddies (∼2 months old) were characterized: a surface cyclonic eddy (CC1) and a subsurface anticyclonic eddy (AA1). The distributions of salinity and dissolved oxygen, together with nutrients, suggested that both eddies were sites of vertical injection of high nutrient concentrations from the Equatorial Subsurface Water mass (ESSW) into the upper layer in the CTZ. In addition, eddy AA1, in combination with an upwelling plume, was involved in the offshore advection of nutrients from the core of the ESSW located in the coastal zone. At shallow depths (CTZ.

  17. The impact of anthropogenic factors on the occurrence of molybdenum in stream and river sediments of central Upper Silesia (Southern Poland

    Directory of Open Access Journals (Sweden)

    Pasieczna Anna

    2017-12-01

    Full Text Available In our study, a detailed survey was conducted with the aim to determine the distribution and possible anthropogenic sources of molybdenum in river and stream sediments in the central Upper Silesian Industrial Region (Southern Poland, where for many years, iron and zinc smelters as well as coking and thermal power plants were operating. At the same time, this has also been a residential area with the highest population density in the country. Sediments (1397 samples in total were collected from rivers and streams, and analysed for the content of molybdenum and 22 other elements. ICP-AES and CV-AAS methods were applied for the determination of the content of elements. The studies revealed molybdenum content in the range of 5 mg·kg−1. The spatial distribution of molybdenum demonstrated by the geochemical map has indicated that the principal factor determining its content in sediments is the discharge of wastewater from steelworks and their slag heaps. Another source of this element in sediments has been the waste of the historical mining of zinc ore and metallurgy of this metal. Additionally, molybdenum migration from landfills of power plants, coal combustion and Mo emission to the atmosphere and dust fall-out have been significant inputs of Mo pollution to the sediments.

  18. Variation in the distribution of wintering anchovy Engraulis japonicus and its relationship with water temperature in the central and southern Yellow Sea

    Science.gov (United States)

    Niu, Mingxiang; Wang, Jun

    2017-09-01

    In the present study, we investigated a shift in the spatial distribution of wintering anchovy ( Engraulis japonicus) and its relationship with water temperature, using data collected by bottom trawl surveys and remote sensing in the central and southern Yellow Sea, during 2000-2015. Our results indicate that the latitudinal distribution of wintering anchovy varied between years, but there was no consistent pattern in the direction of change (north or south). Wintering anchovy did not move northward with increasing water temperature. However, the latitudinal distribution of wintering anchovy correlated well with 10°C and 11°C isotherms. The results of both a one-step and a two-step generalized additive model indicated that water temperature was associated with both presence and biomass of wintering anchovy. This paper is the first to systematically examine the relationship between anchovy distribution and water temperature using a variety of techniques. All the findings confirm the impact of water temperature on wintering anchovy distribution, which has important implications for the continued management of the anchovy resource and the enhancement of marine fishery resources in the Yellow Sea, especially as the climate changes. However water temperature only partly explains the species distribution of anchovy, and stock characteristics also affect fishery distribution. Therefore, other factors should be considered in future research.

  19. Origin and pathways of pro- and retrograde fluids, PTt paths and fluid-mineral equilibria from Alpine veins of the Central Alps : case studies of the Fibbia and Amsteg areas

    OpenAIRE

    Heijboer, Tjerk Cornelis

    2006-01-01

    In order to constrain the conditions of and processes related to vein formation and the origins of mineralising fluids, field work, multiple geochemical methods applied to whole rocks, minerals, and fluid inclusions, as well as thermodynamic modeling on these veinwall rock systems have been carried out. The focus of this study was on vein and fissure systems from two particular areas in the external parts of the Central Alps: the Fibbia area in the southern Gotthard massif and ...

  20. CL-imaging and ion microprobe dating of single zircons from a high-grade rock from the Central Zone, Limpopo Belt, South Africa: Evidence for a single metamorphic event at ˜2.0 Ga

    Science.gov (United States)

    Mouri, H.; Brandl, G.; Whitehouse, M.; de Waal, S.; Guiraud, M.

    2008-02-01

    The combination of ion microprobe dating and cathodoluminescence (CL) imaging of zircons from a high-grade rock from the Central Zone of the Limpopo Belt were used to constrain the age of metamorphic events in the area. Zircon grains extracted from an orthopyroxene-gedrite-bearing granulite were prepared for single crystal CL-imaging and ion microprobe dating. The grains display complex zoning when using SEM-based CL-imaging. A common feature in most grains is the presence of a distinct core with a broken oscillatory zoned structure, which clearly appears to be the remnant of an original grain of igneous origin. This core is overgrown by an unzoned thin rim measuring about 10-30 μm in diameter, which is considered as new zircon growth during a single metamorphic event. Selected domains of the zircon grains were analysed for U, Pb and Th isotopic composition using a CAMECA IMS 1270 ion microprobe (Nordsim facility). Most of the grains define a near-concordant cluster with some evidence of Pb loss. The most concordant ages of the cores yielded a weighted mean 207Pb/ 206Pb age of 2689 ± 15 (2 σ) Ma, interpreted as the age of the protolith of an igneous origin. The unzoned overgrowths of the zircon grains yielded a considerably younger weighted mean 207Pb/ 206Pb age of ˜2006.5 ± 8.0 Ma (2 σ), and these data are interpreted to reflect closely the age of the ubiquitous high-grade metamorphic event in the Central Zone. This study shows clearly, based on both the internal structure of the zircons and the data obtained by ion microprobe dating, that only a single metamorphic event is recorded by the studied 2.69 Ga old rocks, and we found no evidence of an earlier metamorphic event at ˜2.5 Ga as postulated earlier by some workers.

  1. Mass changes of Southern and Northern Inylchek Glacier, Central Tian Shan, Kyrgyzstan, during ∼1975 and 2007 derived from remote sensing data

    Science.gov (United States)

    Shangguan, D. H.; Bolch, T.; Ding, Y. J.; Kröhnert, M.; Pieczonka, T.; Wetzel, H. U.; Liu, S. Y.

    2015-04-01

    Glacier melt is an essential source of freshwater for the arid regions surrounding the Tian Shan. However, the knowledge about glacier volume and mass changes over the last decades is limited. In the present study, glacier area, glacier dynamics and mass changes are investigated for the period ~1975-2007 for Southern Inylchek Glacier (SIG) and Northern Inylchek Glacier (NIG), the largest glacier system in Central Tian Shan separated by the regularly draining Lake Merzbacher. The area of NIG increased by 2.0 ± 0.1 km2 (~1.3%) in the period ~1975-2007. In contrast, SIG has shrunk continuously in all investigated periods since ~1975. Velocities of SIG in the central part of the ablation region reached ~100-120 m a-1 in 2002/2003, which was slightly higher than the average velocity in 2010/2011. The central part of SIG flows mainly towards Lake Merzbacher rather than towards its terminus. The measured velocities at the distal part of the terminus downstream of Lake Merzbacher were below the uncertainty, indicating very low flow with even stagnant parts. Geodetic glacier mass balances have been calculated using multi-temporal digital elevation models from KH-9 Hexagon (representing the year 1975), SRTM3 (1999), ALOS PRISM (2006) and SPOT-5 high-resolution geometrical (HRG) data (2007). In general, a continuous mass loss for both SIG and NIG could be observed between ~1975 and 2007. SIG lost mass at a rate of 0.43 ± 0.10 m w.e. a-1 and NIG at a rate of 0.25 ± 0.10 m w.e. a-1 within the period ~1975-1999. For the period 1999-2007, the highest mass loss of 0.57 ± 0.46 m w.e. a-1 was found for NIG, whilst SIG showed a potential moderate mass loss of 0.28 ± 0.46 m w.e. a-1. Both glaciers showed a small retreat during this period. Between ~1975 and 1999, we identified a thickening at the front of NIG with a maximum surface elevation increase of about 150 m as a consequence of a surge event. In contrast significant thinning (>0.5 m a-1) and comparatively high velocities

  2. Assessment of village-wise groundwater draft for irrigation: a field-based study in hard-rock aquifers of central India

    Science.gov (United States)

    Ray, R. K.; Syed, T. H.; Saha, Dipankar; Sarkar, B. C.; Patre, A. K.

    2017-07-01

    Extracted groundwater, 90% of which is used for irrigated agriculture, is central to the socio-economic development of India. A lack of regulation or implementation of regulations, alongside unrecorded extraction, often leads to over exploitation of large-scale common-pool resources like groundwater. Inevitably, management of groundwater extraction (draft) for irrigation is critical for sustainability of aquifers and the society at large. However, existing assessments of groundwater draft, which are mostly available at large spatial scales, are inadequate for managing groundwater resources that are primarily exploited by stakeholders at much finer scales. This study presents an estimate, projection and analysis of fine-scale groundwater draft in the Seonath-Kharun interfluve of central India. Using field surveys of instantaneous discharge from irrigation wells and boreholes, annual groundwater draft for irrigation in this area is estimated to be 212 × 106 m3, most of which (89%) is withdrawn during non-monsoon season. However, the density of wells/boreholes, and consequent extraction of groundwater, is controlled by the existing hydrogeological conditions. Based on trends in the number of abstraction structures (1982-2011), groundwater draft for the year 2020 is projected to be approximately 307 × 106 m3; hence, groundwater draft for irrigation in the study area is predicted to increase by ˜44% within a span of 8 years. Central to the work presented here is the approach for estimation and prediction of groundwater draft at finer scales, which can be extended to critical groundwater zones of the country.

  3. Assessment of village-wise groundwater draft for irrigation: a field-based study in hard-rock aquifers of central India

    Science.gov (United States)

    Ray, R. K.; Syed, T. H.; Saha, Dipankar; Sarkar, B. C.; Patre, A. K.

    2017-12-01

    Extracted groundwater, 90% of which is used for irrigated agriculture, is central to the socio-economic development of India. A lack of regulation or implementation of regulations, alongside unrecorded extraction, often leads to over exploitation of large-scale common-pool resources like groundwater. Inevitably, management of groundwater extraction (draft) for irrigation is critical for sustainability of aquifers and the society at large. However, existing assessments of groundwater draft, which are mostly available at large spatial scales, are inadequate for managing groundwater resources that are primarily exploited by stakeholders at much finer scales. This study presents an estimate, projection and analysis of fine-scale groundwater draft in the Seonath-Kharun interfluve of central India. Using field surveys of instantaneous discharge from irrigation wells and boreholes, annual groundwater draft for irrigation in this area is estimated to be 212 × 106 m3, most of which (89%) is withdrawn during non-monsoon season. However, the density of wells/boreholes, and consequent extraction of groundwater, is controlled by the existing hydrogeological conditions. Based on trends in the number of abstraction structures (1982-2011), groundwater draft for the year 2020 is projected to be approximately 307 × 106 m3; hence, groundwater draft for irrigation in the study area is predicted to increase by ˜44% within a span of 8 years. Central to the work presented here is the approach for estimation and prediction of groundwater draft at finer scales, which can be