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Sample records for coalfields southern north

  1. Demand for housing and the development of the Selby Coalfield: a case study. [North Yorkshire

    SciTech Connect

    Edwards, C.; Webb, M.G.

    1980-06-01

    Development in the Selby Coalfield in North Yorkshire will bring in new miners who will require housing services estimated at between 865 to 1725 housing units. Using Selby as a case study, the demand for local authority housing and the financial deficit this will create are estimated. Financing strategies to meet this deficit are considered as well as their effect on rents and coal prices. The cost of housing should be included as a relevant development cost of projects of this type. Other policy issues are whether these special housing needs are included in the planning of Central Government Housing and the responsibility of the Selby District Council to finance housing. (21 references, 8 tables. (DCK)

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

    NASA Astrophysics Data System (ADS)

    Phiri, Cryton; Wang, Pujun; Nyambe, Imasiku Anayawa

    2016-06-01

    This study attempts to augment geology and potential hydrocarbon play system database not only in the Maamba Coalfield basin of southern Zambia but in other similar continental non-marine Karoo rift basins in the region as well. Geological analyses were conducted through extensive outcrops and exposures and subsurface boreholes. Six (6) major lithofacies (diamictites, conglomerates, sandstones, siltstones, coal and mudstones) represents Lower Karoo Group sequence. Four (4) mudstone core samples were prepared for thin section petrography. In addition, six (6) samples of sandstones obtained from outcrops, exposures and cores were impregnated with blue epoxy before thin sectioning in order to facilitate easy recognition of porosity. Quantification of framework grain composition and porosity was achieved by point counting a total of 300 points per thin section. The identification of diagenetic constituents and pore types was made possible by the use of scanning electron microscopy (SEM). Rock-Eval pyrolysis analyses utilised 35 core samples of mudstones and coal. According to results of the analyses, three (3) deposition settings which include; alluvial, fluvial-lacustrine and lacustrine setting are envisaged. . Fluvial-lacustrine deposits are host to mudstones and coal source rocks and sandstone reservoir rocks. Mudstones and coal source rocks gave the total organic carbon (TOC) that is well above the recommended thresholds of 0.5 wt % and 2.5 wt % of gas and oil generation respectively. The hydrogen index (HI) values are mostly below 200 mg HC/g TOC, indicating fair quantities of type III kerogen. The thermal maturity readings measured by temperature Tmax range from 440 to 485 °C in agreement with calculated vitrinite reflectance (Rocalc) range of 0.76-1.57% indicating mature to post mature stages. This maturation is attributed to the burial temperatures and near-surface heat flows by faults. Production Index (PI) values are less than 0.1 suggesting some hydrocarbon

  3. A new species of Discinites (Noeggerathiales) from the Upper Permian of Weibei Coalfield, North China.

    PubMed

    Jun; Guanglong

    2000-07-01

    A new species of Discinites is described from the Late Permian Upper Shihhotse Formation of the Weibei Coalfield, Shaanxi Province, China. D. hanchengensis sp. nov. has decurrent and disk-like sporophylls with deep-toothed apices, elliptical sporangia and rectangular epidermal cells. The spores are generally of the Calamospora type. The megaspores and microspores are 300-380 and 45-90µm in diameter, respectively. The microspores are similar in size to those of all other species of Discinites that contain Calamospora, but the megaspores are remarkably smaller. The new species represents the first record of Discinites with Calamospora from China and from the Cathaysian flora. Finally, we summarize the associated foliages of Discinites in the Cathaysian flora and find that they are all markedly different from those found in the Euramerican flora.

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

    USGS Publications Warehouse

    Cravotta, Charles A.

    2010-01-01

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

  5. Resource and potential reclamation evaluation of Rattlesnake Butte study area, Dickinson coalfield, North Dakota: summary. Final report 1978-82

    SciTech Connect

    Westman, G.H.; Parish, L.M.

    1982-06-01

    The purpose of this investigation was to collect baseline data for establishing reclamation objectives and lease stipulations. The report includes data on climate, physiography, geology, coal resources, and overburden. The study area, located in Southwestern North Dakota, lies within the unglaciated portion of the Great Plains Physiographic Province.

  6. 2. GENERAL VIEW LOOKING NORTH, SHOWING THE SOUTHERN FACADE OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. GENERAL VIEW LOOKING NORTH, SHOWING THE SOUTHERN FACADE OF THE NORTHERN-MOST CAR BARN (CONSTRUCTED 1893) AT CENTRAL AVENUE AND BOND STREET - Johnstown Passenger Railway Company, Car Barns, 726 Central Avenue, Johnstown, Cambria County, PA

  7. Thermal history of the Sabero Coalfield (Southern Cantabrian Zone, NW Spain) as revealed by apatite fission track analyses from tonstein horizons: implications for timing of coalification

    NASA Astrophysics Data System (ADS)

    Botor, Dariusz; Anczkiewicz, Aneta A.

    2015-10-01

    Apatite fission track (AFT) central ages from Carboniferous (Stephanian) tonsteins of the Sabero Coalfield, NW Spain, range from 140.8 ± 7.5 to 65.8 ± 8.1 Ma (Cretaceous), with mean c-axis projected track length values ranging from 12.5 to 13.4 μm. Mean random vitrinite reflectance ( R r) of these samples ranges from 0.91 to 1.20 %, which can be translated into maximum palaeotemperatures of ca. 130 to 180 °C. All analysed samples experienced substantial post-depositional annealing. The considerably younger AFT ages compared to the depositional ages of the samples and R r data indicate the certainty of the occurrence of at least one heating event after the deposition of strata. The unimodal track length distributions, the relatively short mean track length, and the rather low standard deviation (SD) (1.0-1.6 μm) indicate a relatively simple thermal history that could be related to the post-Late Variscan heating event followed by prolonged residence in the apatite partial annealing zone (APAZ). Geological data combined with thermal models of AFT data indicate that Stephanian strata reached the maximum palaeotemperatures in the Permian period, which was therefore the major time of the coalification processes. The Permian magmatic activity was responsible for a high heat flow, which, with the added effect of sedimentary burial, could account for the resetting of the AFT system. It appears that the fault-related hydrothermal activity could have redistributed heat in areas of significant subsidence. Cooling occurred in the Triassic-Cretaceous times after a high heat flow Permian regime. A post-Permian maturation of the Stephanian organic matter is not very likely, since there is no evidence of a high Mesozoic burial that was sufficient to cause a significant increase in the palaeotemperatures. Finally, exhumation and associated erosion rates may possibly have been faster in the Tertiary, causing the present exposure of the studied rocks.

  8. 75 FR 53687 - Southern Montana Electric Generation & Transmission Cooperative, Inc. v. NorthWestern Corporation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-01

    ...] Southern Montana Electric Generation & Transmission Cooperative, Inc. v. NorthWestern Corporation; Notice...) Rules of Practice and Procedure, 18 CFR 385.206, Southern Montana Electric Generation &...

  9. 13. Looking north, from the southern approach to the bridge. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Looking north, from the southern approach to the bridge. The bridge deck, which is concrete with several patch coats of asphalt (now chiefly gravel and some turf), demonstrates a sharp gradient from the abutment to the bridge center line. - Vigo County Bridge No. 139, Spanning Sugar Creek at Seventy-fourth Place, Terre Haute, Vigo County, IN

  10. 2. Southern Light Tower and Northern Light Tower, view north, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Southern Light Tower and Northern Light Tower, view north, south sides - Kennebec River Light Station, South side of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

  11. Southern part of the Sea of Okhotsk, north of Japan

    NASA Image and Video Library

    1974-01-20

    SL4-141-4340 (20 Jan. 1974) --- An oblique view of the southern part of the Sea of Okhotsk, north of Japan, as photographed from the Skylab space station in Earth orbit by one of the Skylab 4 crewmen. The camera used was a hand-held 70mm Hasselblad, and SO-368 medium-speed Ektachrome. NORTH IS AT THE TOP WHEN THE PICTURE IS HELD WITH THE LARGEST LAND MASS AT THE BOTTOM. Most of the land area is Hokkaido Island, Japan. The southern tip of Sakhalin Island (Soviet Union) is in the northwest corner. This photograph was taken to aid in the study of the formation of sea ice. Comparison of these photographs will be made with observations made during a joint USSR-U.S. experiment in the Bering Sea a year earlier. Observations in the Sea of Okhotsk are of interest because the ice has a morphology similar to that of the Bering Sea. Photo credit: NASA

  12. "The Lady Is Not Returning!": Educational Precarity and a Social Haunting in the UK Coalfields

    ERIC Educational Resources Information Center

    Bright, N. Geoffrey

    2016-01-01

    Drawing on research in de-industrialised coal-mining communities in the north of England, this article focuses on how experiences of some young people might be approached through a notion of precarity linked to the idea of a "social haunting" of the coalfields. Concentrating on data gathered in the period after the 2010 change of UK…

  13. "The Lady Is Not Returning!": Educational Precarity and a Social Haunting in the UK Coalfields

    ERIC Educational Resources Information Center

    Bright, N. Geoffrey

    2016-01-01

    Drawing on research in de-industrialised coal-mining communities in the north of England, this article focuses on how experiences of some young people might be approached through a notion of precarity linked to the idea of a "social haunting" of the coalfields. Concentrating on data gathered in the period after the 2010 change of UK…

  14. Variation in the chemistry of macerals in coals of the Mist Mountain Formation, Elk Valley coalfield, British Columbia, Canada

    USGS Publications Warehouse

    Mastalerz, Maria; Bustin, R.M.

    1997-01-01

    Variations in elemental and molecular chemistry of macerals, with vitrinite, semifusinite and sporinite in particular, are discussed for the coal seams of the Mist Mountain Formation in the Elk Valley coalfield, in western Canada. In the south Elk Valley coalfield, carbon content of vitrinite oscillates around 85%, and oxygen content increases gradually up section, from seam A to C. In the north Elk Valley coalfield, carbon content in vitrinite shows marked variations (from 70% to 85%) between the samples and is lower than in the south Elk Valley coalfield, which is consistent with a higher maturation level of south Elk Valley coalfield samples. Sulphur content is below 1% in both coalfields. Semifusinite, in general, has higher carbon and lower oxygen content than vitrinite, whereas cutinite has higher carbon content than vitrinite and slightly higher or comparable to that of semifusinite. Functional group distributions show large variations between the seams and these variations are attributed mainly to differences in a primary depositional environment and only occasionally to later weathering and oxidation processes. The results presented in this paper provide also information on the length and branching of aliphatic chains, which, for liptinite macerals is valuable from the oil generation viewpoint, whereas for semifusinite, it may help to understand reactive versus non-reactive behaviour during coking.

  15. North-Seeking Magnetotactic Gammaproteobacteria in the Southern Hemisphere

    PubMed Central

    Leão, Pedro; Teixeira, Lia C. R. S.; Cypriano, Jefferson; Farina, Marcos; Abreu, Fernanda; Bazylinski, Dennis A.

    2016-01-01

    ABSTRACT Magnetotactic bacteria (MTB) comprise a phylogenetically diverse group of prokaryotes capable of orienting and navigating along magnetic field lines. Under oxic conditions, MTB in natural environments in the Northern Hemisphere generally display north-seeking (NS) polarity, swimming parallel to the Earth's magnetic field lines, while those in the Southern Hemisphere generally swim antiparallel to magnetic field lines (south-seeking [SS] polarity). Here, we report a population of an uncultured, monotrichously flagellated, and vibrioid MTB collected from a brackish lagoon in Brazil in the Southern Hemisphere that consistently exhibits NS polarity. Cells of this organism were mainly located below the oxic-anoxic interface (OAI), suggesting it is capable of some type of anaerobic metabolism. Magnetosome crystalline habit and composition were consistent with elongated prismatic magnetite (Fe3O4) particles. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that this organism belongs to a distinct clade of the Gammaproteobacteria class. The presence of NS MTB in the Southern Hemisphere and the previously reported finding of SS MTB in the Northern Hemisphere reinforce the idea that magnetotaxis is more complex than we currently understand and may be modulated by factors other than O2 concentration and redox gradients in sediments and water columns. IMPORTANCE Magnetotaxis is a navigational mechanism used by magnetotactic bacteria to move along geomagnetic field lines and find an optimal position in chemically stratified sediments. For that, magnetotactic bacteria swim parallel to the geomagnetic field lines under oxic conditions in the Northern Hemisphere, whereas those in the Southern Hemisphere swim antiparallel to magnetic field lines. A population of uncultured vibrioid magnetotactic bacteria was discovered in a brackish lagoon in the Southern Hemisphere that consistently swim northward, i.e., the opposite of the overwhelming majority of other

  16. Shallow gas in Cenozoic sediments of the Southern North Sea

    NASA Astrophysics Data System (ADS)

    Trampe, Anna F.; Lutz, Rüdiger; Franke, Dieter; Thöle, Hauke; Arfai, Jashar

    2013-04-01

    Shallow petroleum systems in the southern North Sea are known for several decades but they were not actively explored for a long time. In recent years these unconventional shallow petroleum systems are studied in greater detail and one shallow gas field (A-12) is in production in the Netherlands. Additionally, oil was encountered in Miocene sandstones in the southern Danish North Sea (Lille John well) just north of the Danish-German border. Seismic amplitude anomalies are an indication for hydrocarbons in sediments. Therefore we have mapped the occurrence of seismic amplitude anomalies in the German North Sea based on more than 25.000 km of 2D seismic data and around 4.000 km2 of 3D seismic data. Amplitude anomalies are ubiquitous phenomena in the study area. These anomalies are not only caused by hydrocarbons but also by changing lithologies e.g. peat or fluid migration. Therefore several classes of seismic anomalies, e.g. bright spots, chimneys, blanking areas and velocity pull-down were mapped. Examples for these classes were studied with AVO (amplitude variation with offset) analyses to verify the existence or non-existence of gas in the sediments. Shallow gas can be produced and transported through the dense pipeline grid of the southern and central North Sea or it could be burned offshore close to wind parks in small power plants and the electric energy then transported through the existing power connections of the wind parks. Thus enabling a continuous energy supply during calm wind periods. This study is carried out within the framework of the project "Geoscientific Potential of the German North Sea (GPDN)" in which the Cenozoic sedimentary system was mapped in great detail. A detailed model of delta evolution (Baltic river system) was developed which serves as a structural framework. The studied interval is time equivalent to the Utsira formation which is used offshore Norway for sequestration of CO2. These different possibilities of using or exploiting

  17. Predicting North American Scolytinae invasions in the Southern Hemisphere.

    PubMed

    Lantschner, Maria Victoria; Atkinson, Thomas H; Corley, Juan C; Liebhold, Andrew M

    2017-01-01

    Scolytinae species are recognized as one of the most important tree mortality agents in coniferous forests worldwide, and many are known invaders because they are easily transported in wood products. Nonnative trees planted in novel habitats often exhibit exceptional growth, in part because they escape herbivore (such as Scolytinae) pressure from their native range. Increasing accidental introductions of forest pest species as a consequence of international trade, however, is expected to diminish enemy release of nonnative forest trees. In this context, there is need to characterize patterns of forest herbivore species invasion risks at global scales. In this study, we analyze the establishment potential of 64 North American Scolytinae species in the Southern Hemisphere. We use climate-based ecological niche models (MaxEnt) to spatially define the potential distribution of these Scolytinae species in regions of the Southern Hemisphere were pines are planted. Our model predicts that all of the pine-growing regions of the Southern Hemisphere are capable of supporting some species of North American Scolytinae, but there are certain "hotspot" regions, southeastern Argentina, Bolivia, Chile, Peru and southwestern Australia, that appear to be suitable for a particularly large number of species. The species with the highest predicted risk of establishment were Dendroctonus valens, Xyleborus intrusus, Hylastes tenuis, Ips grandicollis, Gnathotrichus sulcatus, and Ips calligraphus. Given that global commerce is anticipated to continue to increase, we can expect that more Scolytinae species will continue to establish outside their range. Our results provide information useful for identifying a global list of potential invasive species in pine plantations, and may assist in the design of comprehensive strategies aimed at reducing pest establishment in Southern Hemisphere forest plantations. © 2016 by the Ecological Society of America.

  18. Spatial Organization of Decadal and Bidecadal Rainfall On Southern North America and Southern South America

    NASA Astrophysics Data System (ADS)

    Lucero, O. A.; Rodriguez, N. C.

    The spatial organization of decadal and bidecadal components (fluctuations) of annual rainfall is identified in this research for two regions: 1) southern South America, and 2) southern North America (conterminous USA, southeastern Canada and northern and central Mexico). Findings indicate that these decadal and bidecadal components have highly-coherent wave-like spatial organization. Two types of organization of decadal and bidecadal components of annual rainfall were identified: a train of propagating fluctuations, and quasi-standing fluctuations. For decadal components, such patterns alternate in time. A widespread change in the spatial organization of decadal com- ponents of annual rainfall took place simultaneously in both continents in 1932. The bidecadal component is organized as standing fluctuations in southern North Amer- ica, and as travelling fluctuations in southern South America. The spatial pattern of decadal fluctuations of annual rainfall has 12- and 13-year cycle; and the spatial pat- tern of bidecadal fluctuations has predominantly 21- and 22-year cycles. Correspond- ing author's email: omarabellucero@yahoo.com

  19. Southern borderland of Triassic Laurasia in north-east Iran

    NASA Astrophysics Data System (ADS)

    Ruttner, A. W.

    1993-04-01

    Results obtained by Iranian and European geoscientists in the critical area to the north-east of the North Iran Suture east of Mashhad are desribed and discussed. A slightly metamorphosed ophiolite belt, outcropping as the south easterly continuation of the previously known ophiolites of Mashhad along the north eastern perimeter of the Fariman-Torbat-e-Jam depression, proved to be either the remnant of a Permian ocean floor or more likely the remnant of a narrow ocean trough. There is as yet no proof of a Triassic age for this ophiolitic belt. To the north of this ophiolitic belt an epicontinental Triassic sequence is exposed at the southern edge of Laurasia in the erosional Window of Aghdarband. This is the result of intermittent sedimentation in a pull-apart basin along sinistral strike-slip faults. The Triassic of Aghdarband has much in common with other deposits of the Triassic Tethys; however, it shows a few unique features, e.g. the Early Anisian Nicomedites fauna of a palaeobiogeographic North Tethyan Subprovince, or volcanogenic sedimentation during the late Anisian and the entire Ladinian. Permian ophiolites outcropping at the south-west corner of the Aghdarband erosional Window are transgressively overlain by basal conglomerats of this Triassic sequence. Hence the existence of a Triassic ocean south of Laurasia is very unlikely. This is an agreement with paleomagnetic data which suggest that the Central Iranian microcontinent was in direct contact with Laurasia during Triassic times. These palaeomagnetic data also suggest a clockwise rotation of the Central East Iran microplate during Triassic times (contrary to the anticlockwise rotation of this microplate in post-Triassic times). The sinistral strike-slip faulting and compression from the south-west which controls the structure of the Triassic may be derivative sequels to this clockwise rotation. All Eo-Cimmerian deformations of the Triassic rocks (e.g. folding, thrust faulting, strike-slip faulting

  20. Salt tectonics in the southern North Sea, Netherlands

    SciTech Connect

    Remmelts, G. )

    1993-09-01

    Large parts of the southern North Sea are underlain by Upper Permian Zechstein salt. A vast amount of this sequence, originally more than 1000 m thick, has migrated into salt structures. Many hydrocarbon accumulations are related to these structures. The formation of the salt structures may have created structural traps or (by influencing the sedimentation pattern) stratigraphic traps. Salt generally acts as a seal, but depletion of salt can create migration routes into higher strata for hydrocarbons originating from underlying source rocks. The thermal conductivity of the salt can influence the maturity of source rocks in its direct vicinity. Salt structures are formed almost exclusively by Zechstein salt. Minor movement occurred in Triassic evaporites. The development of salt structures is influenced strongly by regional tectonics. Basement faulting probably triggered the salt movement. The dominant structural grain is reflected in the orientation and location of the salt structures. Periods of increased growth rates coincide with tectonic phases. Long walls of salt formed in the northern area where the Triassic north-south orientated faults (which were rejuvenated in Late Jurassic) predominate. Toward the south, the northwest-southeast direction of the Late Jurassic interferes with the north-south trend and gradually becomes the dominant direction. This is reflected in the shortening of the north-south salt structures and eventually in the change in their orientation. Average vertical growth rates have been calculated to be around 0.005-0.035 mm/yr. When correction for suberosion and erosion processes could be quantified and applied to the growth rates, they were significantly higher.

  1. Diet overlap among flatfish species in the southern North Sea.

    PubMed

    Schückel, S; Sell, A F; Kröncke, I; Reiss, H

    2012-06-01

    The diets of two non-commercial flatfish species (solenette Buglossidium luteum and scaldfish Arnoglossus laterna) and two commercial flatfish species (dab Limanda limanda and plaice Pleuronectes platessa) were compared in a study area in the German Bight (southern North Sea) to investigate prey-resource partitioning between these species. The diets of A. laterna and B. luteum mainly comprised crustaceans (harpacticoids, amphipods, cumaceans and decapods), whereas the diet of L. limanda and P. platessa consisted mainly of polychaetes. The Schoener index, calculated for different fish size classes between these flatfish species, showed a biologically significant diet overlap between small-sized L. limanda and P. platessa and B. luteum and A. laterna, using similar prey resources of smaller prey (e.g. amphipods, harpacticoids and juvenile bivalves). In contrast, with increasing body size, a change in the diet of L. limanda and P. platessa towards larger prey occurred (e.g. polychaetes and decapods), resulting in low diet overlap values with B. luteum and A. laterna. Due to these size-related differences in resource use, it is assumed that there is reduced interspecific competition for prey between larger L. limanda and P. platessa and both non-commercial flatfishes, probably facilitating resource partitioning within the same area. In contrast, smaller L. limanda and P. platessa may compete directly for the same prey resources with B. luteum and A. laterna. Furthermore, prey availability of most important prey items of the studied flatfishes was relatively low in the study area. Therefore, increasing abundances of B. luteum and A. laterna in the southern North Sea since the late 1980s, owing to fishing effects and climate change, might affect the population dynamics of L. limanda and P. platessa.

  2. View of north central Wyoming and southern Montana

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A view of approximately 3,600 square miles of north central Wyoming and southern Montana as seen in this Skylab 3 Earth Resources Experiments Package S190-B (five-inch earth terrain camera) photograph taken from the Skylab space station in Earth orbit. The Big Horn River flowing northward crosses between the northwest trending Big Horn Mountains and the Pryor Mountains. Yellowtail Reservoir, in the center of the picture, is impounded by a dam across the Big Horn River. A sharp contrast is clearly evident between the small rectangular crop areas along the Big Horn River (upper right) and the strip farming (yellow) practiced on the rolling hill along the Big Horn River and its tributaries (upper left corner and right edge). The low sun angle enhances the structural features of the mountains as well as the drainage patterns in the adjacent basins. Rock formations appear in this color photograph as they would to the eye from this altitude. The distinctive redbeds can be traced along the fr

  3. A review of southern pine decline in North America

    Treesearch

    David R. Coyle; Kier D. Klepzig; Frank H. Koch; Lawrence A. Morris; John T. Nowak; Steven W. Oak; William J. Otrosina; William D. Smith; Kamal J.K. Gandhi

    2015-01-01

    The southeastern United States is among the most productive forested areas in the world. Four endemic southern pine species – loblolly, longleaf, shortleaf, and slash - contribute significantly to the economic and ecological values in the region. A recently described phenomenon known as Southern Pine Decline (SPD) has been reported as having widespread impact in the...

  4. 50 CFR 226.219 - Critical habitat for the Southern Distinct Population Segment of North American Green Sturgeon...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Distinct Population Segment of North American Green Sturgeon (Acipenser medirostris). 226.219 Section 226... the Southern Distinct Population Segment of North American Green Sturgeon (Acipenser medirostris). Critical habitat is designated for the Southern Distinct Population Segment of North American green...

  5. 50 CFR 226.219 - Critical habitat for the Southern Distinct Population Segment of North American Green Sturgeon...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Population Segment of North American Green Sturgeon (Acipenser medirostris). 226.219 Section 226.219 Wildlife... Distinct Population Segment of North American Green Sturgeon (Acipenser medirostris). Critical habitat is designated for the Southern Distinct Population Segment of North American green sturgeon (Southern DPS) as...

  6. The influence of Southern Ocean winds on the North Atlantic carbon sink

    NASA Astrophysics Data System (ADS)

    Bronselaer, Ben; Zanna, Laure; Munday, David R.; Lowe, Jason

    2016-06-01

    Observed and predicted increases in Southern Ocean winds are thought to upwell deep ocean carbon and increase atmospheric CO2. However, Southern Ocean dynamics affect biogeochemistry and circulation pathways on a global scale. Using idealized Massachusetts Institute of Technology General Circulation Model (MITgcm) simulations, we demonstrate that an increase in Southern Ocean winds reduces the carbon sink in the North Atlantic subpolar gyre. The increase in atmospheric CO2 due to the reduction of the North Atlantic carbon sink is shown to be of the same magnitude as the increase in atmospheric CO2 due to Southern Ocean outgassing. The mechanism can be described as follows: The increase in Southern Ocean winds leads to an increase in upper ocean northward nutrient transport. Biological productivity is therefore enhanced in the tropics, which alters the chemistry of the subthermocline waters that are ultimately upwelled in the subpolar gyre. The results demonstrate the influence of Southern Ocean winds on the North Atlantic carbon sink and show that the effect of Southern Ocean winds on atmospheric CO2 is likely twice as large as previously thought in past, present, and future climates.

  7. 1. View north from StanleyBostitch property toward southern boundary/stone wall ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. View north from Stanley-Bostitch property toward southern boundary/stone wall of Joseph Fry Farm with South County Trail/Route 2 to the east (right) - Joseph Fry Farm Landscape, 2153 South County Trail Road (U.S. Route 2), East Greenwich, Kent County, RI

  8. Forest statistics for the Southern Coastal Plain of North Carolina 1973

    Treesearch

    Noel D. Cost

    1973-01-01

    This report highlights the principal findings of the fourth inventory of the timber resource in the Southern Coastal plain of North Carolina. The inventory was s t a r t e d in November 1972 and completed in August 1973. Three previous inventories, completed in 1937, 1952, and 1962, provide statistics for measuring changes and trends over the past 36 years. In this...

  9. Gene flow from North Africa contributes to differential human genetic diversity in southern Europe.

    PubMed

    Botigué, Laura R; Henn, Brenna M; Gravel, Simon; Maples, Brian K; Gignoux, Christopher R; Corona, Erik; Atzmon, Gil; Burns, Edward; Ostrer, Harry; Flores, Carlos; Bertranpetit, Jaume; Comas, David; Bustamante, Carlos D

    2013-07-16

    Human genetic diversity in southern Europe is higher than in other regions of the continent. This difference has been attributed to postglacial expansions, the demic diffusion of agriculture from the Near East, and gene flow from Africa. Using SNP data from 2,099 individuals in 43 populations, we show that estimates of recent shared ancestry between Europe and Africa are substantially increased when gene flow from North Africans, rather than Sub-Saharan Africans, is considered. The gradient of North African ancestry accounts for previous observations of low levels of sharing with Sub-Saharan Africa and is independent of recent gene flow from the Near East. The source of genetic diversity in southern Europe has important biomedical implications; we find that most disease risk alleles from genome-wide association studies follow expected patterns of divergence between Europe and North Africa, with the principal exception of multiple sclerosis.

  10. Gene flow from North Africa contributes to differential human genetic diversity in southern Europe

    PubMed Central

    Botigué, Laura R.; Henn, Brenna M.; Gravel, Simon; Maples, Brian K.; Gignoux, Christopher R.; Corona, Erik; Atzmon, Gil; Burns, Edward; Ostrer, Harry; Flores, Carlos; Bertranpetit, Jaume; Comas, David; Bustamante, Carlos D.

    2013-01-01

    Human genetic diversity in southern Europe is higher than in other regions of the continent. This difference has been attributed to postglacial expansions, the demic diffusion of agriculture from the Near East, and gene flow from Africa. Using SNP data from 2,099 individuals in 43 populations, we show that estimates of recent shared ancestry between Europe and Africa are substantially increased when gene flow from North Africans, rather than Sub-Saharan Africans, is considered. The gradient of North African ancestry accounts for previous observations of low levels of sharing with Sub-Saharan Africa and is independent of recent gene flow from the Near East. The source of genetic diversity in southern Europe has important biomedical implications; we find that most disease risk alleles from genome-wide association studies follow expected patterns of divergence between Europe and North Africa, with the principal exception of multiple sclerosis. PMID:23733930

  11. The Failure of an Interracial Southern Rhetoric: The Southern Tenant Farmers Union in North Carolina.

    ERIC Educational Resources Information Center

    Griffin, Keith H.

    When the American Civil War ended, the southern aristocracy turned to sharecropping as a means for continuing its existence and for keeping former slaves in the fields. Tenant families during the economic depression of 1929 were forced to live in squalid conditions, and the natural antagonism between whites and blacks was exacerbated by the…

  12. Biochemical characterization of the eelgrass Zostera marina at its southern distribution limit in the North Pacific

    USGS Publications Warehouse

    Cabello-Pasini, Alejandro; Munoz-Salazar, R.; Ward, D.H.

    2004-01-01

    The eelgrass Zostera marina L. is distributed along the Baja California Peninsula (Mexico) where it is exposed to a wide range of irradiances and temperatures that could promote changes in its biochemical composition. Consequently, the objective of this study was to characterize the variations in the levels of chlorophyll, carbohydrates, proteins, fiber, ash and calories in the shoots of Z. marina from the north (San Quintin) and south (Ojo de Liebre and San Ignacio lagoons) of the peninsula. Temperature in the southern lagoons was 5-6??C higher than in the northern lagoon; likewise, in situ irradiance was two-fold greater in the south than in the north. As a result of the lower irradiance levels, the concentration of chlorophyll in the shoots of Z. marina was twice as high (1.7 mg gWW-1) in the northern lagoon than in the southern ones (0.8 mg gWW-1). Similar to chlorophyll levels, the concentration of soluble carbohydrates in the shoots was greater in the northern lagoon than in the southern ones, suggesting that the high levels of chlorophyll are enough to compensate for the low irradiance levels and to maintain a positive carbon balance at San Quintin. On the other hand, the levels of proteins in the shoots from the north of the peninsula were slightly lower than those from the southern populations. In general, these results suggest that the different environmental conditions to which Z. marina is exposed along the peninsula impact its biochemical composition.

  13. Accumulation status of persistent organochlorines in albatrosses from the North Pacific and the Southern Ocean.

    PubMed

    Guruge, K S; Watanabe, M; Tanaka, H; Tanabe, S

    2001-01-01

    Current status of contamination by persistent organochlorines (OCs) such as polychlorinated biphenyles (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), isomers of hexachlorocyclohexane (HCHs), hexachlorobenzene (HCB) and chlordane compounds (CHLs) were examined in 61 individuals belonging to eight albatross species collected from the North Pacific and the Southern Ocean. Generally high OC concentrations were found in albatrosses from the North Pacific than those from the Southern Oceans. Black-footed albatrosses had noticeably high PCBs and DDTs concentrations with mean values of 92 and 33 micrograms/g wet weight in subcutaneous fat, respectively. Among the other OCs, concentration of CHLs was higher than that of HCB in North Pacific albatrosses. HCHs accumulation was the lowest among all the OCs analyzed. Species-specific differences were observed for HCB, CHLs and DDTs in some species in the Southern Ocean. No significant difference of gender and age-related accumulation was observed in total OCs. However, PCB concentrations were higher in mature birds than those from immature ones in the Southern Ocean. Species-specific accumulation patterns of OCs in albatrosses were closely related with their feeding, migration, age and geographical ranges.

  14. Southern Hemisphere water mass conversion linked with North Atlantic climate variability.

    PubMed

    Pahnke, Katharina; Zahn, Rainer

    2005-03-18

    Intermediate water variability at multicentennial scales is documented by 340,000-year-long isotope time series from bottom-dwelling foraminifers at a mid-depth core site in the southwest Pacific. Periods of sudden increases in intermediate water production are linked with transient Southern Hemisphere warm episodes, which implies direct control of climate warming on intermediate water conversion at high southern latitudes. Coincidence with episodes of climate cooling and minimum or halted deepwater convection in the North Atlantic provides striking evidence for interdependence of water mass conversion in both hemispheres, with implications for interhemispheric forcing of ocean thermohaline circulation and climate instability.

  15. Comparison of survival patterns of northern and southern genotypes of the North American tick Ixodes scapularis (Acari: Ixodidae) under northern and southern conditions.

    PubMed

    Ginsberg, Howard S; Rulison, Eric L; Azevedo, Alexandra; Pang, Genevieve C; Kuczaj, Isis M; Tsao, Jean I; LeBrun, Roger A

    2014-08-26

    Several investigators have reported genetic differences between northern and southern populations of Ixodes scapularis in North America, as well as differences in patterns of disease transmission. Ecological and behavioral correlates of these genetic differences, which might have implications for disease transmission, have not been reported. We compared survival of northern with that of southern genotypes under both northern and southern environmental conditions in laboratory trials. Subadult I. scapularis from laboratory colonies that originated from adults collected from deer from several sites in the northeastern, north central, and southern U.S. were exposed to controlled conditions in environmental chambers. Northern and southern genotypes were exposed to light:dark and temperature conditions of northern and southern sites with controlled relative humidities, and mortality through time was recorded. Ticks from different geographical locations differed in survival patterns, with larvae from Wisconsin surviving longer than larvae from Massachusetts, South Carolina or Georgia, when held under the same conditions. In another experiment, larvae from Florida survived longer than larvae from Michigan. Therefore, survival patterns of regional genotypes did not follow a simple north-south gradient. The most consistent result was that larvae from all locations generally survived longer under northern conditions than under southern conditions. Our results suggest that conditions in southern North America are less hospitable than in the north to populations of I. scapularis. Southern conditions might have resulted in ecological or behavioral adaptations that contribute to the relative rarity of I. scapularis borne diseases, such as Lyme borreliosis, in the southern compared to the northern United States.

  16. North-South contraction of the mojave block and strike-slip tectonics in southern california.

    PubMed

    Bartley, J M; Glazner, A F; Schermer, E R

    1990-06-15

    The Mojave block of southern California has undergone significant late Cenozoic north-south contraction. This previously unappreciated deformation may account for part of the discrepancy between neotectonic and plate-tectonic estimates of Pacific-North American plate motion, and for part of the Big Bend in the San Andreas fault. In the eastern Mojave block, contraction is superimposed on early Miocene crustal extension. In the western Mojave block, contractional folds and reverse faults have been mistaken for extensional structures. The three-dimensional complexity of the contractional structures may mean that rigid-block tectonic models of the region based primarily on paleomagnetic data are unreliable.

  17. Use of DINEOF with high frequency geostationary ocean colour data in the southern North Sea.

    NASA Astrophysics Data System (ADS)

    Alvera-Azcárate, Aida; Vanhellemont, Quinten; Ruddick, Kevin; Barth, Alxander; Beckers, Jean-Marie

    2015-04-01

    DINEOF (Data Interpolating Empirical Orthogonal Functions), a technique to reconstruct missing data, is applied to a series of turbidity data of the southern North Sea in 2008, obtained through the Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensor on board Meteosat Second Generation 2. These data are characterised by a very high temporal resolution (15 minutes), and long night-time gaps. An outlier detection approach that exploits the high temporal resolution of the SEVIRI dataset is developed. After removal of outliers, the turbidity data are reconstructed with DINEOF, and a series of tidal cycles are examined at various positions over the southern North Sea. The main objective is to demonstrate the capability of DINEOF to reproduce tidal variability in the reconstructed dataset, and to study the high temporal and spatial variability of turbidity in the southern North Sea. An analysis of the main harmonic constituents (annual cycle, daily cycle, M2 and S2 tidal components) is performed to assess the contribution of each of these modes to the total variability of turbidity.

  18. Incursions of southern-sourced water into the deep North Atlantic during late Pliocene glacial intensification

    NASA Astrophysics Data System (ADS)

    Lang, David C.; Bailey, Ian; Wilson, Paul A.; Chalk, Thomas B.; Foster, Gavin L.; Gutjahr, Marcus

    2016-05-01

    The circulation and internal structure of the oceans exert a strong influence on Earth's climate because they control latitudinal heat transport and the segregation of carbon between the atmosphere and the abyss. Circulation change, particularly in the Atlantic Ocean, is widely suggested to have been instrumental in the intensification of Northern Hemisphere glaciation when large ice sheets first developed on North America and Eurasia during the late Pliocene, approximately 2.7 million years ago. Yet the mechanistic link and cause/effect relationship between ocean circulation and glaciation are debated. Here we present new records of North Atlantic Ocean structure using the carbon and neodymium isotopic composition of marine sediments recording deep water for both the Last Glacial to Holocene (35-5 thousand years ago) and the late Pliocene to earliest Pleistocene (3.3-2.4 million years ago). Our data show no secular change. Instead we document major southern-sourced water incursions into the deep North Atlantic during prominent glacials from 2.7 million years ago. Our results suggest that Atlantic circulation acts as a positive feedback rather than as an underlying cause of late Pliocene Northern Hemisphere glaciation. We propose that, once surface Southern Ocean stratification and/or extensive sea-ice cover was established, cold-stage expansions of southern-sourced water such as those documented here enhanced carbon dioxide storage in the deep ocean, helping to increase the amplitude of glacial cycles.

  19. Comparison of survival patterns of northern and southern genotypes of the North American tick Ixodes scapularis (Acari: Ixodidae) under northern and southern conditions

    USGS Publications Warehouse

    Ginsberg, Howard S.; Rulison, Eric L.; Azevedo, Alexandra; Pang, Genevieve C.; Kuczaj, Isis M.; Tsao, Jean I.; LeBrun, Roger A.

    2014-01-01

    BackgroundSeveral investigators have reported genetic differences between northern and southern populations of Ixodes scapularis in North America, as well as differences in patterns of disease transmission. Ecological and behavioral correlates of these genetic differences, which might have implications for disease transmission, have not been reported. We compared survival of northern with that of southern genotypes under both northern and southern environmental conditions in laboratory trials.MethodsSubadult I. scapularis from laboratory colonies that originated from adults collected from deer from several sites in the northeastern, north central, and southern U.S. were exposed to controlled conditions in environmental chambers. Northern and southern genotypes were exposed to light:dark and temperature conditions of northern and southern sites with controlled relative humidities, and mortality through time was recorded.ResultsTicks from different geographical locations differed in survival patterns, with larvae from Wisconsin surviving longer than larvae from Massachusetts, South Carolina or Georgia, when held under the same conditions. In another experiment, larvae from Florida survived longer than larvae from Michigan. Therefore, survival patterns of regional genotypes did not follow a simple north–south gradient. The most consistent result was that larvae from all locations generally survived longer under northern conditions than under southern conditions.ConclusionsOur results suggest that conditions in southern North America are less hospitable than in the north to populations of I. scapularis. Southern conditions might have resulted in ecological or behavioral adaptations that contribute to the relative rarity of I. scapularis borne diseases, such as Lyme borreliosis, in the southern compared to the northern United States.

  20. Paleoenvironmental control of accumulation and quality of upper Freeport coal bed (Allegheny Formation, Middle Pennsylvanian), Castleman coalfield, Maryland

    SciTech Connect

    Lyons, P.C.; Jacobsen, E.F.; Flores, R.M.

    1984-12-01

    The upper Freeport is generally a thick, widespread coal bed in the north-central Appalachian basin. It is a principal bed mined in the Castleman coalfield, Garrett County, Maryland, as delineated on a new geologic map of the coalfield. In the northern part of the coalfield, the upper Freeport is 21-48 in. (53-122 cm) thick and thickens toward the northwest, where the ash and sulfur contents are generally 7-10 wt.% and less than 1.5 wt.%, respectively. This coal bed thins southward and eastward and is absent from a large area in the central part of the coalfield, where its position is occupied by a carbonaceous claystone or flint clay. Toward the south and east, the upper Freeport coal bed generally contains 12-15 wt.% ash and 1.5-6.2 wt.% sulfur. Lithofacies analysis of the floor rocks and their lateral equivalents indicates deposition of the upper Freeport coal bed in floodplain swamps. Limestone and limy claystone floor rocks in the northwest represent distal floodplain lake deposits. Where the coal is unminable or absent to the south, proximal overbank floodplain shale, siltstone, and silty claystone grade laterally into channel sandstone. The gradation of thin coal into carbonaceous claystone to the south indicates increased oxidation and shoaling in a well-drained swamp. There, the coal has the highest ash and sulfur contents, which probably reflect the influx of detritus and iron-rich clays. Thus, the upper Freeport is thickest and has the lowest ash and sulfur contents where the paleoenvironment was a poorly drained, distal floodplain swamp.

  1. Research and application of the heat transfer model of Coalfield fire

    NASA Astrophysics Data System (ADS)

    Weiguo, Dong; Zhongyong, Cai; Chunxia, Xu

    2010-05-01

    Coalfield fire is a common disaster of human. The status of coalfield fire in the world, the ways and character of coalfield fire heat transfer, were introduced in this paper on the purpose of quantifying the coal burnt in the Coalfield fire, the greenhouse gas released and the exploitation of CDM methodology. The heat of coalfield fire was released into the atmosphere by four ways: radiation, convection, carried by concentrated emission gas and dispersing emission gas. Based on the conservative principle, the heat transfer model of Coalfield fire was established. Based on the energy conservation law and the element conservation principle, the quantity of coal burned and CO2 released of the Coalfield fire can be calculated through the quantity of heat transferred. Applying this model into the practical calculation of the south fire zone of Shuixi Gou Coalfield Fire, Jimsar County, Xinjiang, P.R. China, the result show that the burnt coal of this fire zone is about 41.6 kiloton per year; the quantity of CO2 released is about 106.3 kiloton per year. The establishment of the heat transfer model of Coalfield fire has very important signification for quantifying the evaluation of the influence of coalfield fire to environment and resource, also for exploiting coalfield fire extinguishing CDM methodology.

  2. 50 CFR 226.219 - Critical habitat for the Southern Distinct Population Segment of North American Green Sturgeon...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 10 2014-10-01 2014-10-01 false Critical habitat for the Southern... ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS DESIGNATED CRITICAL HABITAT § 226.219 Critical habitat for...). Critical habitat is designated for the Southern Distinct Population Segment of North American green...

  3. Man in the North Technical Paper. Education in the Canadian North, Report Three: Southern Teachers for the North.

    ERIC Educational Resources Information Center

    Girad, Ghislaine

    The purpose of this study is to investigate professional teaching preparation in the North of teachers who received their training in latitudes south of 60 degrees. The procedure involved: (1) 2 formal meetings of task force members; (2) the dispatching of 2 questionnaires to northern teachers; (3) a series of meetings of native parents and native…

  4. Recent Population Trends in North Carolina and the Southern Region: 1970-1975. Progress Report Soc. 64, 1977.

    ERIC Educational Resources Information Center

    Clifford, William B.

    Estimates of population change and the components of change for North Carolina and its counties were made for the 1970-75 period. Attention was given to the growth patterns in the metropolitan and nonmetropolitan areas of North Carolina and the southern region. Data showed that the state's population grew at a faster rate during this period than…

  5. Shoreline responses to storm impacts: North Norfolk coast, southern North Sea

    NASA Astrophysics Data System (ADS)

    Brooks, Sue; Spencer, Thomas

    2016-04-01

    Recent phases of enhanced mid-latitude storminess (e.g. NW European winter of 2013 - 14) have led to a growing awareness of the considerable impacts of storms on coastal landscapes and their communities. Using aerial photography, bi-annual cross-shore profiles, detailed alongshore ground survey, and offshore/inshore wave buoy and regional tide gauge datasets, this paper considers storm impacts on the barrier coastline of North Norfolk, UK. Firstly, at Scolt Head Island, we show that the barrier dune crest has been progressively set back landwards since 2006 in three storm-related phases, with each shoreline translation being of the order of 5-8 m. However, a fourth storm produced no significant shoreline change, demonstrating that the threshold for morphological change is a function of the combined effects of still water level and wave height at the shore, the magnitude and duration of these components, and the timing of their interaction. Secondly, we consider recovery times in the system against periods of quiescence and heightened storm activity on this coast. Thirdly, it has been argued that future changes in extreme water level will be governed by mean sea level rise. Long-term rates of North Norfolk barrier retreat (1.15 m a-1, 1891-2013) have occurred under a regional rate of relative sea level rise over the 20th century of 2.7 ± 0.4 mm a-1 (Lowestoft tide gauge, 1900-2014). If there is a broad correlation between rates of barrier retreat and sea level rise, then recent increases in the rate of regional sea level rise (4.4 ± 1.1 mm a-1, 1993-2011) imply a considerable acceleration in the rate of barrier migration over the remainder of the 21st century.

  6. North Pecan Island field: a mature trend discovery in Miocene of southern Louisiana

    SciTech Connect

    Bauer, A.G.; McCormick, J.A.

    1985-02-01

    The Exxon 1 M.J. Epley discovery well for North Pecan Island field was completed in early 1982 as a discovery of significant new gas and condensate reserves in the mature Miocene trend of south Louisiana. The field is located in Vermilion Parish within a large megablock between 2 major down-to-the basin growth-fault systems and is on the southern end of a south-plunging structural nose. Traps in 2 fault segments are formed in southeasterly dipping beds upthrown to 2 north dipping, sealing faults. Six separate Robulus chambersi sandstones contain gas and condensate reserves. Major gas and condensate reserves from sandstone reservoirs in the R. chambersi section were discovered in the mid-1960s 3.3 mi. west in the Pecan island field and in the North Freshwater Bayou field, 5 mi northeast of the North Pecan Island field discovery. Several earlier dry holes just north of the discovery were drilled seeking to extend production from the upstructure Fire Island field (3 mi north), which produced a limited amount of gas and condensate from R. chambersi sandstones. Extensive structural and isopach mapping, aided by new high-resolution seismic data, revealed the North Pecan Island prospect to be structural high to production at Pecan Island and that the prospective section was deposited over a growing paleostructure. Four wells have been completed to date in the field, with flow rates as high as 30 MMCFGB. Current estimates place the new field recoverable at approximately 250 bcf of gas and 6 million bbl condensate.

  7. Comparison of Archean and Phanerozoic granulites: Southern India and North American Appalachians

    NASA Technical Reports Server (NTRS)

    Mcsween, Harry Y., Jr.; Kittleson, Roger C.

    1988-01-01

    Archean granulites at the southern end of the Dharwar craton of India and Phanerozoic granulites in the southern Appalachians of North America share an important characteristic: both show continuous transitions from amphibolite facies rocks to higher grade. This property is highly unusual for granulite terranes, which commonly are bounded by major shears or thrusts. These two terranes thus offer an ideal opportunity to compare petrogenetic models for deep crustal rocks formed in different time periods, which conventional wisdom suggests may have had different thermal profiles. The salient features of the Archean amphibolite-to-granulite transition in southern India have been recently summarized. The observed metamorphic progression reflects increasing temperature and pressure. Conditions for the Phanerozoic amphibolite-to-granulite transition in the southern Appalachians were documented. The following sequence of prograde reactions was observed: kyanite = sillimanite, muscovite = sillimanite + K-feldspar, partial melting of pelites, and hornblende = orthopyroxene + clinopyroxene + garnet. The mineral compositions of low-variance assemblages in mafic and intermediate rocks are almost identical for the two granulite facies assemblages. In light of their different fluid regimes and possible mechanisms for heat flow augmentation, it seems surprising that these Archean and Phanerozoic granulite terranes were apparently metamorphosed under such similar conditions of pressure and temperature. Comparison with other terrains containing continuous amphibolite-to-granulite facies transitions will be necessary before this problem can be addressed.

  8. Quantification of tertiary exhumation in the United Kingdom southern North Sea using sonic velocity data

    SciTech Connect

    Hillis, R.R.

    1995-01-01

    Sonic velocities from the Upper and Middle Chalk (Upper Cretaceous), the Bunter Sandstone and the Bunter Shale (both Lower Triassic) were used to independently quantify apparent exhumation (height above maximum burial depth) in the United Kingdom (UK) southern North Sea. Apparent exhumation is the displacement, on the depth axis, of a given velocity/depth trend from the normal (unaffected by exhumation) trend. Apparent exhumation results derived from the Upper and Middle Chalk, the Bunter Sandstone, and the Bunter Shale are statistically similar. The consistency of results from carbonate and clastic units suggests that, at a formational and regional scale, over-compaction (i.e., anomalously high sonic velocity) in all three units analyzed reflects previously greater burial depth, rather than sedimentological and/or diagenetic processes, and validates the use of lithologies other than shale in maximum burial depth studies. The consistency of results from units of Early Triassic to Late Cretaceous age suggests that Tertiary exhumation was of sufficiently great magnitude to mask any earlier Mesozoic periods of exhumation, and the maximum Mesozoic-Cenozoic burial depth in the southern North Sea was attained prior to Tertiary exhumation. The proposed magnitudes of exhumation are generally greater than those previously published for the southern North Sea, but they are consistent with recent estimates from apatite fission track analysis. Cretaceous-Tertiary burial prior to exhumation must have been of great magnitude and more rapid than suggested by the preserved stratigraphy. The effect of this extra burial and subsequent exhumation on sedimentary rock decompaction procedure and thermal maturation modeling is illustrated for the Cleethorpes-1 and 44/7-1 wells, and must also be incorporated in modeling reservoir diagenesis. The regional, Tertiary tectonic uplift associated with exhumation must have had a thick-skinned origin.

  9. Developmental defects in pelagic embryos of several flatfish species in the Southern North sea

    NASA Astrophysics Data System (ADS)

    Cameron, P.; Berg, J.; Dethlefsen, V.; Von Westernhagen, H.

    In the spring of 1984 through and in the summer of 1987 pelagic flatfish eggs were collected in horizontal subsurface hauls with a 1-m ring net in the southern North Sea between 51°49' to 55°30'N and 2°30' to 8°00'E. The flatfish eggs were observed alive for their developmental stage and aberrations from normal development. Flatfish eggs occurring in the winter ichthyoplankton of the southern North Sea were dab, Limanda limanda; flounder. Platichthys flesus; plaice, Pleuronectes platessa, and long rough dab, Hippoglossoides platessoides. Summer samples contained dab, turbot, Psetta maxima; little sole, Buglossidium luteum; common sole, Solea solea; Norwegian topknot, Phrynorhombus norwegicus, and lemon sole, Microstomus kitt. In winter as well as in summer eggs of dab were the most abundant in the southern North Sea with up to 249 eggs·m -3 surface water in winter and 26 eggs·m -3 in summer. The investigations revealed considerable quantities of abnormally developed flatfish embryos in the plankton samples. Highest malformation rates were recorded for the early stages of dab (44.4%) followed by flounder (41.3%) and plaice (26.0%) in winter; in summer these rates were for dab 18.9%, for turbot 14.1% and for little sole 12.5%. Generally malformation rates decreased with development. Areas of high malformation rates were off the river estuaries and in near-shore areas along the Dutch and German coasts. Malformation rates decreased with the distance from the coast. Causes and effects of the occurrence of malformations during embryonic development are discussed.

  10. Characterization of Phaeocystis globosa (Prymnesiophyceae), the blooming species in the Southern North Sea

    NASA Astrophysics Data System (ADS)

    Rousseau, Véronique; Lantoine, François; Rodriguez, Francisco; LeGall, Florence; Chrétiennot-Dinet, Marie-Josèphe; Lancelot, Christiane

    2013-02-01

    Despite significant research dedicated to the marine genus Phaeocystis, which forms large blooms in the coastal waters of the Southern North Sea, some aspects of the taxonomy and biology of this species still suffer from a sketchy knowledge. It is currently admitted that P. globosa is the species that blooms in the Southern North Sea. This has however, never been confirmed by SSU rDNA sequencing which constitutes nowadays, together with the morphology of the haploid flagellate, a reliable taxonomic criterion to distinguish between Phaeocystis species. Also, although the fine morphology of the haploid scaly flagellate is well known, there is a lack of comparable and harmonized description of the other cell types, i.e. colonial cells and diploid flagellates, previously identified within the Phaeocystis life cycle. In this study, we used SSU rDNA sequencing, light and electron scanning microscopy and flow cytometry to identify and characterize three cell types produced in controlled and reproducible manner from two strains of Phaeocystis isolated from the Belgian coastal zone. Our morphometry and sequencing data confirm unambiguously that P. globosa is the species that blooms in the Southern North Sea, but suggest in addition that both strains are representative of the original P. globosa Scherffel. Our study compares, for the first time since the species description, the fine morphometry and ploidy features of diploid colonial cells, diploid and haploid flagellates originating from same strains, providing therefore unambiguous identification criteria for distinguishing them from each other. The diploid stage, colonial or flagellated cell, is thus characterized by a naked surface, has a size range nearly twice that of the haploid flagellate and do not produce the chitinous filaments specific of the haploid stage. Colonial cells lack flagella and haptonema but possess on their apical side two appendages, which elongate to form the flagella of the diploid flagellate.

  11. Pleistocene glaciation in the blue ridge province, southern appalachian mountains, north Carolina.

    PubMed

    Berkland, J O; Raymond, L A

    1973-08-17

    Glacial polish, grooves, and striations discovered at an elevation of 1370 meters in the headwaters of Boone Fork on Grandfather Mountain, North Carolina, indicate the former, existence of alpine glaciation at a latitude of 36 degrees 07'N. The Boone Fork glacier was located 890 kilometers south of the previously recognized southern limit of alpine glaciation in the Appalachian Mountains, and 350 kilometers southeast of the nearest point on the Laurentide ice sheet. This find has significant implications for studies of Pleistocene geomorphology, paleobiology, and paleoclimatology in the eastern United States.

  12. Dimethylsulfoniopropionate (DMSP) cell quota of key Southern North Sea spring diatoms and Phaeocystis globosa.

    NASA Astrophysics Data System (ADS)

    Speeckaert, Gaëlle; Gypens, Nathalie; Lancelot, Christiane; Borges, Alberto V.

    2015-04-01

    Dimethylsulfide (DMS) in the ocean results of complex transformations of dimethylsulfoniopropionate (DMSP) produced by phytoplankton under different controls, including microbial transformation pathways. The phytoplankton composition is an important factor of variability due to the species dependence of the DMSP production and conversion to DMS. To better appraise the link between phytoplankton diversity and the DMS(P) cycling in the Southern North Sea we present measurements of the DMSP cell quota of key spring phytoplankton species (Skeletonema costatum, Thalassiosira rotula, Rhizosolenia delicatula, Asterionella glacialis, Nitzschia closterium, Chaetoceros debilis, Chaetoceros socialis and Phaeocystis globosa) isolated from the North Sea and maintained in non-limiting and axenic laboratory culture conditions. Results are discussed with regards to literature data and hypothesis currently used in DMS(P) biogeochemical models.

  13. Benthic macrofauna communities of the submersed Pleistocene Elbe valley in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Rehm, Peter; Rachor, Eike

    2007-06-01

    Macrozoobenthic community structure was studied in two surveys along a transect of 13 stations following the submersed Pleistocene Elbe valley in the south-eastern North Sea during May to June 2000 and March 2001. Two replicates of bottom samples were taken with a van Veen grab of 0.1 m2 sampling size. In order to analyse the benthic macrofauna communities, the animals obtained were identified and counted, and MDS and cluster analysis were performed. Out of 200 taxa identified, 84 were polychaetes, 46 molluscs, 40 crustaceans, 15 echinoderms, and 15 belonged to other groups. Mean abundance was 4,860 individuals per m2, mean biomass 32.9 g ash free dry mass per m2. Mean diversity was 1.76 and mean evenness 0.54. The macrofauna of the Pleistocene Elbe valley is composed of three associations according to the cluster analysis. Each association is described by a combination of characterizing and discriminating species. An Amphiura-brachiata― Tellimya-ferruginosa-association was found in the south-eastern part of the depression, whereas a transitional association with elements of both assemblages lead to an Amphiura- filiformis― Galathowenia- oculata― Nuculoma- tenuis-association in the north-western part of the valley. In the context of the entire southern North Sea, both associations are small-scale substructures, and as such are contained in the Nucula- nitidosa-community and the Amphiura- filiformis-community, respectively. A north-westward shift of the community of the southern Elbe valley was found and discussed as a possible consequence of warm winters of the last decades.

  14. Modelling survival and connectivity of Mnemiopsis leidyi in the southern North Sea and Scheldt estuaries

    NASA Astrophysics Data System (ADS)

    van der Molen, J.; van Beek, J.; Augustine, S.; Vansteenbrugge, L.; van Walraven, L.; Langenberg, V.; van der Veer, H. W.; Hostens, K.; Pitois, S.; Robbens, J.

    2014-06-01

    Three different models were applied to study the reproduction, survival and dispersal of Mnemiopsis leidyi in the Scheldt estuaries and the southern North Sea: a high-resolution particle tracking model with passive particles, a low resolution particle tracking model with a reproduction model coupled to a biogeochemical model, and a dynamic energy budget (DEB) model. The results of the models, each with its strengths and weaknesses, suggest the following conceptual situation: (i) the estuaries possess enough retention capability to keep an overwintering population, and enough exchange with coastal waters of the North Sea to seed offshore populations; (ii) M. leidyi can survive in the North Sea, and be transported over considerable distances, thus facilitating connectivity between coastal embayments; (iii) under current climatic conditions, M. leidyi may not be able to reproduce in large numbers in coastal and offshore waters of the North Sea, but this may change with global warming - however this result is subject to substantial uncertainty. Further quantitative observational work is needed on the effects of temperature, salinity and food availability on reproduction and on mortality at different life stages to improve models such as used here.

  15. Comparisons of The Habitat Utilization Of Top Predators In The Southern Ocean And The North Pacific

    NASA Astrophysics Data System (ADS)

    Costa, D. P.; Robinson, P.; Huckstadt, L. E.; Crocker, D. E.; Goebel, M. E.

    2010-12-01

    Northern and Southern elephant seals (Mirounga angustirostris, M. leonina) separated some 4 MYA. While these congeners are physiologically very similar and thus have the potential to forage in similar ways they inhabit very different habitats. While southern elephant seals (SES) are distributed throughout the southern ocean, northern elephant seals (NES) are limited to the Northeast Pacific Ocean and range over lower latitudes than SES. In order to compare and contrast the physiological capability and response to different habitats we compared the foraging behavior of 167 adult female northern elephant seals (Año Nuevo and San Benitos Islands) and 55 southern elephant seals (Livingston Island, Antarctic Peninsula) using satellite telemetry and dive recorders. As expected both species carried out very similar dive depths (NES 509m ± 166 vs SES 345m±79) and dive durations (NES 23.0 min ± 6.7; SES 22.5 min ± 5.0). However, there were significant differences in their foraging pattern that we attribute to differences in the availability of continental shelf and suitable foraging habitat. While 85% of NES females foraged offshore, the dominant strategy for SES was benthic foraging on the continental shelf. Even with the differences in habitat, the fundamental components of their foraging patterns remained the same as when they foraged pelagically they both species relied on persistent large scale oceanographic features where mixing enhances productivity such as the North Pacific Transition zone (NES) and the Southern Antarctic Circumpolar Current Front (SES). Given the very different habitats and prey species consumed by these two species their overall foraging behavior is surprisingly similar suggesting that as a mesopelagic predator the elephant seal design is rather robust.

  16. Source term balance in a severe storm in the Southern North Sea

    NASA Astrophysics Data System (ADS)

    van Vledder, Gerbrant Ph.; Hulst, Sander Th. C.; McConochie, Jason D.

    2016-12-01

    This paper presents the results of a wave hindcast of a severe storm in the Southern North Sea to verify recently developed deep and shallow water source terms. The work was carried out in the framework of the ONR funded NOPP project (Tolman et al. 2013) in which deep and shallow water source terms were developed for use in third-generation wave prediction models. These deep water source terms for whitecapping, wind input and nonlinear interactions were developed, implemented and tested primarily in the WAVEWATCH III model, whereas shallow water source terms for depth-limited wave breaking and triad interactions were developed, implemented and tested primarily in the SWAN wave model. So far, the new deep-water source terms for whitecapping were not fully tested in shallow environments. Similarly, the shallow water source terms were not yet tested in large inter-mediate depth areas like the North Sea. As a first step in assessing the performance of these newly developed source terms, the source term balance and the effect of different physical settings on the prediction of wave heights and wave periods in the relatively shallow North Sea was analysed. The December 2013 storm was hindcast with a SWAN model implementation for the North Sea. Spectral wave boundary conditions were obtained from an Atlantic Ocean WAVEWATCH III model implementation and the model was driven by hourly CFSR wind fields. In the southern part of the North Sea, current and water level effects were included. The hindcast was performed with five different settings for whitecapping, viz. three Komen type whitecapping formulations, the saturation-based whitecapping by Van der Westhuysen et al. (2007) and the recently developed ST6 whitecapping as described by Zieger et al. (2015). Results of the wave hindcast were compared with buoy measurements at location K13 collected by the Dutch Ministry of Transport and Public Works. An analysis was made of the source term balance at three locations, the deep

  17. Offshore Windfarm Impact on Pelagic Primary Production in the Southern North Sea

    NASA Astrophysics Data System (ADS)

    Slavik, Kaela; Zhang, Wenyan; Lemmen, Carsten; Wirtz, Kai

    2016-04-01

    As society struggles to find solutions to mitigate global warming, the demand for renewable energy technology has increased. Especially investment in offshore wind energy has proliferated in the European Union, with projections over the next 15 years estimating an over 40 fold increase in total offshore wind electricity. Though built with the goal of reducing the environmental impacts associated with traditional energy production, the long-term ecological impacts of offshore windfarm structures is not yet well understood. The consequences are of particular importance in the southern North Sea, where the expansion of offshore windfarms is focused. Our study investigates how the gradual accumulation of epifaunal biomass on submerged substrate at offshore windfarms impacts ecosystem services in the southern North Sea. Biofouling is governed predominately by the filter feeder Mytilus edulis, which, as an ecological engineer, will further alter the surrounding benthic and pelagic environment. We reconstruct the distribution of benthic filter feeders in the SNS and generate scenarios of increased potential distribution based on available information of Mytilus edulis settlement at turbines and of turbine locations. These maps are coupled through the MOSSCO (Modular Coupling System for Shelves and Coasts) to state-of-the-art and high resolution hydrodynamic and ecosystem models. We find a substantial change in pelagic primary production as a result of additional Mytilus edulis growth at offshore windfarms.

  18. Harbour porpoises (Phocoena phocoena) stranded along the southern North Sea: an assessment through metallic contamination.

    PubMed

    Mahfouz, Céline; Henry, Françoise; Courcot, Lucie; Pezeril, Sylvain; Bouveroux, Thibaut; Dabin, Willy; Jauniaux, Thierry; Khalaf, Gaby; Amara, Rachid

    2014-08-01

    Throughout the last few years, the southern North Sea has witnessed an increase in the number of stranded marine mammals, particularly the harbour porpoise (Phocoena phocoena). This species is subject to several potential threats such as exposure to contaminants, changes in food supply, marine traffic and fishery by-catch. The aims of this study were to investigate potential associations between contaminants and health status and to analyze spatial and temporal trends of metal concentrations in harbour porpoises. Selected trace elements (As, Cd, Cr, Cu, Hg, Mn, Se, V and Zn) were measured in kidneys and livers of 105 harbour porpoises stranded along the southern North Sea (French and Belgian coasts from 2006 to 2013) and 27 stranded along the Bay of Biscay (French coast from 2009 to 2012). Porpoises that died from infectious disease displayed significant higher hepatic concentrations of Cd, Hg, Se and Zn compared to healthy porpoises that died from physical trauma. Adult porpoises displayed significant higher concentrations of Cd, Cr, Hg, Se and V in livers compared to juveniles. No spatial or temporal trends in metal concentrations were detected in our study. The results of the present study suggested that chemical contamination may represent one of many threats encountered by harbour porpoises, but it cannot explain alone the increase in the number of stranded individuals.

  19. Orthogonal fracture formation in the South Wales coalfield: implications from a field study and fluid overpressure of quartz veins

    NASA Astrophysics Data System (ADS)

    Fukunari, Tetsuzo; Gudmundsson, Agust

    2014-05-01

    Orthogonal fractures can easily make networks in geological formations and are of great importance for permeability and fluid transport in subsurface reservoirs. Despite many studies focusing on the formation of orthogonal fractures, no clear and generally accepted model has been established as yet although their formation is widely believed to occur during crustal uplift or exhumation. Here we provide new insights into their mechanism of formation based on the results of a fieldwork and analytical study of orthogonal fractures and quartz veins in alternating sand-shale layers in the South Wales coalfield, which is one of foreland basins developed in relation with north-south compression of the Variscan Orogeny. More than 3,000 fractures were measured at various localities extending from southern end to northern end of the basin. Most of the fractures in the sandstone layers, are extension fractures (mode I cracks), and become arrested at contacts with shale layers. The fractures strike north-south and east-west. Some fractures are filled with shale, probably supplied from adjacent shale layers, suggesting the shale behaved as semi-ductile material at the time of fracture formation. A remarkable observation is that most of the fractures are perpendicular to bedding planes throughout the basin. This is despite the fact that the beds are strongly folded as a result of the Variscan Orogeny. The perpendicular attitude suggests that the fracture formation somewhat predates or coincides with that of folding. This implies that the orthogonal fractures in this area did not form during crustal uplift/exhumation but rather during basin growth at the time of regional north-south convergence and associated compression of the Variscan Orogeny. By using aspect (length/thickness) ratios of quartz veins of the same geometry as the orthogonal fractures, fluid overpressure (driving pressure) at the time of fracture formation is estimated at around 33 MPa for fractures striking north

  20. Concentration and toxic potential of polychlorinated biphenyl congeners in migratory oceanic birds from the North Pacific and the Southern Ocean.

    PubMed

    Guruge, K S; Tanaka, H; Tanabe, S

    2001-09-01

    Concentrations of PCBs and their toxic potential were examined in subcutaneous fat of eight albatross and one petrel species collected from the North Pacific and the Southern Oceans. Among all the species analyzed, high PCB levels were found in adult male blackfooted albatross from the North Pacific with the mean value of 92 microg/g wet weight. No significant gender difference in PCB accumulation was observed (P>0.1). The mean PCB levels in Southern Oceanic birds were 1 or 2 orders of magnitude lower than those from the North Pacific albatrosses. A regional-specific accumulation of non-ortho coplanar congeners were observed, most birds from the Southern Ocean had higher IUPAC 169 levels while IUPAC 126 concentrations were higher in those from the North Pacific. The estimated toxic equivalents for black-footed and Laysan albatrosses from the North Pacific were in the same range of some fish-eating birds, which were highly contaminated by PCBs. The correlation between ratio of IUPAC 169/126 concentration and total PCBs concentration indicated the possibility of induction in cytochrome P450 activities in North Pacific albatrosses (P<0.01). The calculated hazard indices indicated that black-footed and Laysan albatrosses inhabiting in the North Pacific had similar threshold levels which were known to cause toxic effects in some populations of fish-eating birds.

  1. Geophysical Constraints on the Location and Nature of the North Saharan Flexure in Southern Tunisia

    NASA Astrophysics Data System (ADS)

    Gabtni, Hakim; Jallouli, Chokri; Mickus, Kevin; Zouari, Hédi; Turki, Mohamed Moncef

    2005-11-01

    Gravity data, integrated with seismic refraction/reflection data, well data and geological investigations, were used to determine the location of the paleogeographic boundary between the Precambrian Saharan domain and the younger Tunisian Atlas domain. This boundary (North Saharan Flexure or NSF) has not been as clearly defined as it has been to the west in Algeria and Morocco. The gravity data analysis, which included the construction of complete Bouguer and residual gravity anomaly maps, revealed that the Atlasic domain is characterized by relative negative gravity anomalies and numerous linear gravity trends implying a thick and deformed sediment cover. The Saharan domain is characterized by relatively positive gravity anomalies with few gravity trends implying a thin and relatively undeformed sediment cover. An edge-enhancement analysis of the residual gravity anomalies revealed that the NSF is characterized by a series of discontinuous east- and northwest-trending linear anomalies south of 34°N that are not related to the well-known faults within the Gafsa and Accident de Medenine regions. Based on the continuity of the amplitudes of seismic reflection data and the trends of the residual gravity anomalies, the NSF is not an abrupt discontinuity but a series of step faults dipping toward the Atlasic domain. To obtain a more quantitative representation of the southern edge of Tunisian Atlas, a regional gravity model constrained by two wells and seismic reflection/refraction data was constructed along a north-south trending profile which confirms the presence of thicker sediments north of the NSF. Our analysis shows that the NSF has controlled the depositional environment of the sedimentary rocks within the region since at least Triassic time and has acted as a barrier to Atlasic deformation south of the NSF. The NSF is considered an important tectonic feature that has controlled the paleogeographic evolution of the southern margin of the Tethys Ocean, and it

  2. Arc-continent collision on the southern Margin of North America: Cuba and Hispaniola

    NASA Astrophysics Data System (ADS)

    Draper, G.; Pindell, J.

    2004-12-01

    Comparison of the geology of Cuba and Hispaniola demonstrates how different tectonic styles can be produced in closely adjacent parts of the accretion arc. Cuba is a laterally extensive fold-and-thrust belt that includes a narrow belt of Early Cretaceous to Campanian arc rocks, ocean crust, sub-oceanic mantle and metamorphosed continental crust. Hispaniola represents a broader and more complete (although deformed) Early Cretaceous to Eocene arc structure with a single accreted, metamorphosed continental terrane. We suggest that Cuba's preset arc terrane is essentially a fore-arc that was underplated by continental crust in the Campanian collision of the Greater Antilles arc with southern Yucatan. Following this collision, the proto Caribbean lithosphere detached from the eastern margin of Yucatan resulting in rapid, north directed rollback. This, in turn, developed extension of the over-riding Cuban lithosphere and exhumed the underplated continental crust as extensional metamorphic core complexes. The present Cuban fold belt was formed as a result of collision with the southern margin of North America in the mid-Eocene. In contrast, Hispaniola was to the east of Cuba and was not detectably involved in the Campanian collisional event. At present, it is not clear if the extensional rollback event that affected Cuba had any significant effect on Hispaniola. Hispaniola's collision with North America began in the late Eocene(?) and culminated in the Oligocene and was highly oblique. This event resulted in highly oblique, south-verging thrusting that telescoped the back arc basin. It also produced a pop-up structure that reveals evidence of an earlier, mid-Cretaceous collisional event within the arc. This oblique collision persists until the present.

  3. Rotliegende group event stratigraphy, Quadrants 42 and 47, Southern North Sea

    SciTech Connect

    Wrigley, R. ); Philling, D.; Melvin, A. )

    1993-09-01

    The Easington Catchment Area is located in United Kingdom continental shelf Quadrants 42 and 47, 40 km offshore north Humberside, in the Southern North Sea basin. The area is located on the northern margin of the Rotliegende play fairway, where reservoir development, facies and quality is highly variable. Conventional lithostratigraphic nomenclature for the Lower Permian of the United Kingdom continental shelf Southern North Sea basin proposes a twofold subdivision of the Rotliegende Group with the boundary between the Leman Sandstone Formation (LSF) and the Silverpit Claystone Formation (SCF), often portrayed on wireline logs as a sharp contact. Analysis of core and log data from wells in the area demonstrates that the boundary is diachronous. Given the complexity of the depositional environment, the adoption of a sharp boundary is potentially misleading when correlating wells and predicting reservoir trends. This paper describes the development of a tectonic and climatically controlled event stratigraphy for the Rotliegende Group. In the absence of biostratigraphic data, sabkha and lacustrine intercalations have been interpreted as isochronous markers which equate to maximum flooding surfaces in marine sequences. Where sabkha intercalations are absent, laterally equivalent sand sheet packages or fluvial events have been used for correlation. A series of paleogeographic models and well correlations have been produced which are highly predictive in terms of facies distribution. The results of the study also highlight the diachronous nature of the LSF and SCF and the control of Carboniferous paleo-relief on facies and thickness variations in the Rotliegende Group. The results of the study have been used to predict Rotliegende Group facies and reservoir quality on a regional basis, a critical play element for successful exploration in this mature area.

  4. Energy generation potential from coals of the Charqueadas Coalfield, RS, Brazil

    NASA Astrophysics Data System (ADS)

    Correa da Silva, Z. C.; Heemann, R.; Castro, L.; Ketzer, J. M.

    2009-04-01

    Three coal seams, I2B (Inferior 2), I1F (Inferior 1) and MB, from the Charqueadas Coalfield located in the central-east region of the State of Rio Grande do Sul, Southern Brazil were studied on the basis of geological, petrographic, chemical and geochemical techniques and correlated to the SR1, SR2 and SR3 coal seams from the Santa Rita Coalfield. The Charqueadas Coalfield reserves reach 2,993x106 metric tons of coal distributed in six coal seams. The study of sedimentary and organic facies is made on the subsurface data from five boreholes drilled in the area. There show a well marked lateral facies change from sub aquatic to sub aerial environment, conditioned by both the water level variations and the irregular palaeotopography of the basement. The coals change from limnic to forest-terrestrial moor types characterized by variations of composition in terms of macerals, microlithotypes and mineral matter. The coals are rich in mineral matter (28 to 40%); the vitrinite content reaches 50 %, inertinite 44 % and liptinite varies from 10 to 30 %, in mineral matter free basis. Among the microlithotypes carbominerite and vitrite are predominant. Rank studies carried out by different methods (vitrinite reflectance, max and red-green quotient among others) gave conflicting results, which are explained by the strong bituminization of the vitrinite. However, agreement between fluorescence measurements and organic geochemical parameters (e.g. CPI values) confirm that the coals are of a High Volatile Bituminous B/C (ASTM) or Gasflammkohle (DIN) rank. Based on these characteristics, the Charqueadas coal seams show great potential for use in Underground Coal Gasification (UCG) and Enhanced Coalbed Methane (ECBM) projects. Nowadays the state of Rio Grande do Sul is rapidly growing and needs to increase the energy efficiency to attend the industrial demands, filling the gap between supply and energy generation. As with conventional IGCC, UCG gas can be used to generate

  5. Salt-influenced structures in the mesozoic-tertiary cover of the southern North Sea, U.K.

    SciTech Connect

    Coward, M.; Stewart, S.

    1996-12-31

    A structural model encompassing the southern North Sea Basin west of the Central Graben has been developed that combines gravity gliding of the postsalt cover with basement tectonics. The basin differs from many salt basins in that it forms a closed system. Section construction and balancing through the cover of the North Sea need to take into account thin-skinned and thick-skinned extensions and contractions. The North Sea salt formed in Permian time in two large oval basins separated by the Mid North Sea High. The shape of these basins reflects variable patterns of thermal subsidence. Subsequent salt tectonics was governed by local graben structures and by regional uplift and subsidence. Rifting initiated during the Triassic and allowed reactive and locally passive diapirs to develop in the post-salt cover. In the southern North Sea, the Dowsing graben system in the cover is offset from the Dowsing fault zone below the salt. This offset in extensional structures probably relates to the salt thickness and to the position of the surface hinge line that controlled the onset of gravity gliding in the postsalt section. Gravity gliding of the cover into the Triassic-Jurassic Sole Pit trough and away from zones of rift flank uplift was associated with Late Jurassic-Early Cretaceous extension in the Central North Sea; gliding caused asymmetric compressional pillows to develop downslope. Gravity spreading of the cover during the Late Cretaceous-early Tertiary was associated with tilting during thermal subsidence of the southern North Sea Basin, enhanced by pulses of tectonic inversion in the southern North Sea basement. The resultant glide tectonics formed new small grabens upslope and compressional pillows downslope. Where the compressional pillows were eroded sufficiently or faulted later, the salt broke through the thinned cover to produce new active and then passive diapirs, which drained the pillows to produce new rim synclines.

  6. Abandoned mine shafts and levels in the British coalfields

    NASA Astrophysics Data System (ADS)

    Davies, Christopher S.

    1988-07-01

    Industrial dereliction is a concern to all societies. In the United Kingdom the British government is trying to make its abandoned coalfields more attractive to new industry through a combination of land reclamation and job incentive programs. The most ambitious of these projects occurs in the South Wales Coalfield, which records 200 years of land defilement and the highest unemployment amplitudes in mainland Britain. In returning this area to a semblance of its previous state, problems arise over how best to fill and cap the many derelict pit shafts and abandoned shallow mines that riddle this region. This analysis reports on the methods of treatment used to achieve this end, along with the procedures used to minimize ground subsidence, water pollution, noxious gas emission, and the potential for physical injury. These environmental controls have application to the United States and Western Europe, where pockets of industrial blight are also symptomatic of a troubled local economy.

  7. Siting of USArray Seismic Stations in North Carolina and southern Virginia: Experience of NC-1 Team

    NASA Astrophysics Data System (ADS)

    Martin, P.; Howard, J.; Horne, T.

    2012-12-01

    The USArray component of the EarthScope, a transportable array of 400 seismometers installed in a grid about 70 km apart, is in the next two years entering its final stage with station deployment along the Atlantic coast of the United States. Here, we present the experience of the student-faculty team from North Carolina Central University (NCCU) in finding and documenting the suitable sites for the twenty five USArray stations in North Carolina and southern Virginia. The ideal sites are easily accessible yet far from traffic and other sources of noise, with good cell phone coverage, sun exposure and out of flood-prone areas. Although the initial selection of potential locations was done using geospatial mapping and analysis software provided by EarthScope, finding and finalizing the sites involved driving more then 1,000 miles each week for over two months inspecting possible site locations. Aside from driving, the majority of time was spent talking about the EarthScope project and hosting of USArray stations to mostly reluctant landowners. In addition to facing various challenges in finding appropriate sites due to land use issues, such as suburban sprawl of central North Carolina, or topography factors, such as low lying flood prone coastal areas, by far the major challenge was finding the landowners willing to host the seismic station for the necessary three years. In addition to involving students from an HBCU in seismology related project and increasing the visibility of NCCU geophysics program in the University and local community through publicity releases in local media and on university web site, the project had an important outreach component. As North Carolina is located along the seismically quiet, passive Atlantic margin, most residents are not familiar with earthquakes and seismology and the siting experience provided students an opportunity to practice explaining the earthquake research to the general public. The dialog also highlighted science

  8. Artificial neural networks for modeling time series of beach litter in the southern North Sea.

    PubMed

    Schulz, Marcus; Matthies, Michael

    2014-07-01

    In European marine waters, existing monitoring programs of beach litter need to be improved concerning litter items used as indicators of pollution levels, efficiency, and effectiveness. In order to ease and focus future monitoring of beach litter on few important litter items, feed-forward neural networks consisting of three layers were developed to relate single litter items to general categories of marine litter. The neural networks developed were applied to seven beaches in the southern North Sea and modeled time series of five general categories of marine litter, such as litter from fishing, shipping, and tourism. Results of regression analyses show that general categories were predicted significantly moderately to well. Measured and modeled data were in the same order of magnitude, and minima and maxima overlapped well. Neural networks were found to be eligible tools to deliver reliable predictions of marine litter with low computational effort and little input of information. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. A model for tides and currents in the English Channel and southern North Sea

    USGS Publications Warehouse

    Walters, Roy A.

    1987-01-01

    The amplitude and phase of 11 tidal constituents for the English Channel and southern North Sea are calculated using a frequency domain, finite element model. The governing equations - the shallow water equations - are modifed such that sea level is calculated using an elliptic equation of the Helmholz type followed by a back-calculation of velocity using the primitive momentum equations. Triangular elements with linear basis functions are used. The modified form of the governing equations provides stable solutions with little numerical noise. In this field-scale test problem, the model was able to produce the details of the structure of 11 tidal constituents including O1, K1, M2, S2, N2, K2, M4, MS4, MN4, M6, and 2MS6.

  10. Surface Forcing from CH4 at the North Slope of Alaska and Southern Great Plains Sites

    NASA Astrophysics Data System (ADS)

    Collins, W.; Feldman, D.; Turner, D. D.

    2014-12-01

    Recent increases in atmospheric CH4 have been spatially heterogeneous as indicated by in situ flask measurements and space-borne remote-sensing retrievals from the AIRS instrument, potentially leading to increased radiative forcing. We present detailed, specialized measurements at the DOE ARM North Slope of Alaska (NSA) and Southern Great Plains (SGP) sites to derive the time-series of both CH4 atmospheric concentrations and associated radiative implications at highly-contrasting natural and anthropogenic sources. Using a combination of spectroscopic measurements, in situ observations, and ancillary data for the atmospheric thermodynamic state from radiosondes and cloud-clearing from active sounders, we can separate out the contribution of CH4 to clear-sky downwelling radiance spectra and its infrared surface forcing. The time-series indicates year-to-year variation in shoulder season increases of CH4 concentration and forcing at NSA and large signals from anthropogenic activity at SGP.

  11. Anisotropy from SKS splitting across the Pacific-North America plate boundary offshore southern California

    NASA Astrophysics Data System (ADS)

    Ramsay, Joseph; Kohler, Monica D.; Davis, Paul M.; Wang, Xinguo; Holt, William; Weeraratne, Dayanthie S.

    2016-10-01

    SKS arrivals from ocean bottom seismometer (OBS) data from an offshore southern California deployment are analysed for shear wave splitting. The project involved 34 OBSs deployed for 12 months in a region extending up to 500 km west of the coastline into the oceanic Pacific plate. The measurement process consisted of removing the effects of anisotropy using a range of values for splitting fast directions and delay times to minimize energy along the transverse seismometer axis. Computed splitting parameters are unexpectedly similar to onland parameters, exhibiting WSW-ENE fast polarization directions and delays between 0.8 and 1.8 s, even for oceanic plate sites. This is the first SKS splitting study to extend across the entire boundary between the North America and Pacific plates, into the oceanic part of the Pacific plate. The splitting results show that the fast direction of anisotropy on the Pacific plate does not align with absolute plate motion (APM), and they extend the trend of anisotropy in southern California an additional 500 km west, well onto the oceanic Pacific plate. We model the finite strain and anisotropy within the asthenosphere associated with density-buoyancy driven mantle flow and the effects of APM. In the absence of plate motion effects, such buoyancy driven mantle flow would be NE-directed beneath the Pacific plate observations. The best-fit patterns of mantle flow are inferred from the tomography-based models that show primary influences from foundering higher-density zones associated with the history of subduction beneath North America. The new offshore SKS measurements, when combined with measurements onshore within the plate boundary zone, indicate that dramatic lateral variations in density-driven upper-mantle flow are required from offshore California into the plate boundary zone in California and western Basin and Range.

  12. Introducing mixotrophy into a biogeochemical model describing an eutrophied coastal ecosystem: The Southern North Sea

    NASA Astrophysics Data System (ADS)

    Ghyoot, Caroline; Lancelot, Christiane; Flynn, Kevin J.; Mitra, Aditee; Gypens, Nathalie

    2017-04-01

    Most biogeochemical/ecological models divide planktonic protists between phototrophs (phytoplankton) and heterotrophs (zooplankton). However, a large number of planktonic protists are able to combine several mechanisms of carbon and nutrient acquisition. Not representing these multiple mechanisms in biogeochemical/ecological models describing eutrophied coastal ecosystems can potentially lead to different conclusions regarding ecosystem functioning, especially regarding the success of harmful algae, which are often reported as mixotrophic. This modelling study investigates, for the first time, the implications for trophic dynamics of including 3 contrasting forms of mixotrophy, namely osmotrophy (using alkaline phosphatase activity, APA), non-constitutive mixotrophy (acquired phototrophy by microzooplankton) and also constitutive mixotrophy. The application is in the Southern North Sea, an ecosystem that faced, between 1985 and 2005, a significant increase in the nutrient supply N:P ratio (from 31 to 81 mole N:P). The comparison with a traditional model shows that, when the winter N:P ratio in the Southern North Sea is above 22 molN molP-1 (as occurred from mid-1990s), APA allows a 3 to 32% increase of annual gross primary production (GPP). In result of the higher GPP, the annual sedimentation increases as well as the bacterial production. By contrast, APA does not affect the export of matter to higher trophic levels because the increased GPP is mainly due to Phaeocystis colonies, which are not grazed by copepods. The effect of non-constitutive mixotrophy depends on light and affects the ecosystem functioning in terms of annual GPP, transfer to higher trophic levels, sedimentation, and nutrient remineralisation. Constitutive mixotrophy in nanoflagellates appears to have little influence on this ecosystem functioning. An important conclusion from this work is that different forms of mixotrophy have different impacts on system dynamics and it is thus important to

  13. Van Horn Sandstone, Trans-Pecos Texas: Evidence for Late Cambrian rifting along southern North America

    SciTech Connect

    Hongshuan, Ye; Soegaard, K. . Programs in Geosciences)

    1993-02-01

    The Van Horn Sandstone in the Trans-Pecos region of west Texas is interpreted as a rift sequence which developed in response to Cambrian breakup along the southern margin of the North American continent. The Van Horn Sandstone consists exclusively of braided alluvial sediments and occupies relatively small isolated basins in the vicinity of the town of Van Horn. The sandstone is in structural unconformable contact above intensely deformed Precambrian sediments which are < 1,123 Ma old. The Van Horn Sandstone is overlain by more than 650 meters of earliest Ordovician to Mississippian shallow-marine shelf sediments. Geohistory analysis of the overlying Paleozoic shelf sediments indicates that subsidence was driven by thermal contraction of the crust and that the shallow-marine sediments represent a drift sequence. Subsidence history curves correspond with theoretical thermal decay curves where [beta] = 1.2 and suggest that thermal subsidence commenced in Late Cambrian time about 510 Ma ago. Increased crustal attenuation, resulting in development of an ocean basin, occurred between Van Horn and the original location of deep water sediments presently exposed in the Marathon uplift to the south. Proposed Late Cambrian breakup south of Van Horn is coeval with rifting in the southern Oklahoma aulachogen and Rome trough in the Appalachian Mountains, but post-dates the main Late Proterozoic rifting event between 625 and 555 Ma along the eastern and western freeboard of North American. The significance of diachronous rifting in Eocambrian-Cambrian time is unclear at present but has consequences for fragmentation of the late Precambrian supercontinent Rodinia'.

  14. Postglacial formation and dynamics of North Patagonian Rainforest in the Chonos Archipelago, Southern Chile

    NASA Astrophysics Data System (ADS)

    Haberle, S. G.; Bennett, K. D.

    2004-12-01

    Pollen analysis of continuous sediment cores from two lakes in the northern Chonos Archipelago (44°S) in southern Chile shows a complete postglacial record of vegetation change. The fossil records indicate that deglaciation was complete in the northern Chonos by at least 13,600 14C yr BP. Ericaceous heath and grassland persisted for more than 600 years after deglaciation under the influence of dry/cold climates and frequent burning. Nothofagus- Pilgerodendron- Podocarpus forest, with modern analogues in the southern Chonos Archipelago, was established across the northern islands by 12,400 14C yr BP under increasingly warm and wet climates. There is no evidence for a return to cooler climates during the Younger Dryas chronozone. The rise of Tepualia stipularis and Weinmannia trichosperma as important forest components between 10,600 and 6000 14C yr BP may be associated with climates that were warmer than present. The collapse of Pilgerodendron communities during this time may have been triggered by a combination of factors related to disturbance frequency including tephra deposition events, fire and climate change. After 6000 14C yr BP Pilgerodendron recovers and Nothofagus-Pilgerodendron-Tepualia forest persists until the present. European logging and burning activity may have increased the susceptibility of North Patagonian Rainforest to invasion by introduced species and to future collapse of the long-lived Pilgerodendron communities.

  15. "Narrow and Filthy Alleys of the City?": The Residential Settlement Patterns of Black Southern Migrants to the North.

    ERIC Educational Resources Information Center

    Tolnay, Stewart E.; Crowder, Kyle D.; Adelman, Robert M.

    2000-01-01

    Analysis of the 1970 Neighborhood Characteristics Public Use Microdata Sample indicates that recent (1965-70) southern Black migrants to the North resided in the "best" neighborhoods (less poverty, segregation, and family instability), while earlier Black migrants lived in the worst neighborhoods. Recent migrants also received the…

  16. Morphology and channel evolution of small streams in the southern Blue Ridge mountains of western North Carolina

    Treesearch

    David Leigh

    2010-01-01

    Small streams are understudied in the Southern Blue Ridge Mountains, yet they constitute a huge portion of the drainage network and are relevant with respect to human impact on the landscape and stream restoration efforts. Morphologies of 44 streams (0.01 to 20 km2 watersheds) from western North Carolina are characterized and couched in the context of historical...

  17. Effects of prescribed fire and fire surrogates on Saproxylic coleoptera in the Southern Appalachians of North Carolina

    Treesearch

    Joshua W. Campbell; James L. Hanula; Thomas A. Waldrop

    2008-01-01

    We examined the effects of forest management practices (prescribed burning, mechanical, and prescribed burn plus mechanical) on saproxylic forest Coleoptera in the southern Appalachian Mountains of North Carolina. During the 2-yr study, we captured 37,191 Coleoptera with baited multiple- unnel traps and pipe traps, comprising 20 families and 122 species that were used...

  18. Forest growth of Mississippi's north unit - A case study of the Southern Forest surveys growth estimation procedures

    Treesearch

    Dennis M. May

    1988-01-01

    This report presents the procedures by which the Southern Forest Inventory and Analysis unit estimates forest growth from permanent horizontal point samples. Inventory data from the 1977-87 survey of Mississippi's north unit were used to demonstrate how trees on the horizontal point samples are classified into one of eight components of growth and, in turn, how...

  19. "Narrow and Filthy Alleys of the City?": The Residential Settlement Patterns of Black Southern Migrants to the North.

    ERIC Educational Resources Information Center

    Tolnay, Stewart E.; Crowder, Kyle D.; Adelman, Robert M.

    2000-01-01

    Analysis of the 1970 Neighborhood Characteristics Public Use Microdata Sample indicates that recent (1965-70) southern Black migrants to the North resided in the "best" neighborhoods (less poverty, segregation, and family instability), while earlier Black migrants lived in the worst neighborhoods. Recent migrants also received the…

  20. Participatory Research in North America; A Perspective on Participatory Research in Latin America; Participatory Research in Southern Europe.

    ERIC Educational Resources Information Center

    Gaventa, John; And Others

    1988-01-01

    The authors present perspectives on the employment of participatory research techniques in three areas: (1) North America (Gaventa); (2) Latin America (de Souza); and (3) Southern Europe (Orefice). Discussion focuses on participatory research strategies for popular groups, purposes and considerations regarding participatory research, and the role…

  1. Integrated pest management of the southern green stinkbug, Nezara viridula (Hemiptera: Pentatomidae) on tomato in North Florida

    USDA-ARS?s Scientific Manuscript database

    The Southern Green Stinkbug, Nezara viridula is a serious insect pest of tomatoes in north Florida. We evaluated three trap crops and three refuge crops to investigate their potential for IPM of N. viridula. The experimental trap crops and refuge crops were, striped sunflower, WGF sorghum and brown ...

  2. Are the birch trees in Southern England a source of Betula pollen for North London?

    PubMed

    Skjøth, C A; Smith, M; Brandt, J; Emberlin, J

    2009-01-01

    Birch pollen is highly allergenic. Knowledge of daily variations, atmospheric transport and source areas of birch pollen is important for exposure studies and for warnings to the public, especially for large cities such as London. Our results show that broad-leaved forests with high birch tree densities are located to the south and west of London. Bi-hourly Betula pollen concentrations for all the days included in the study, and for all available days with high birch pollen counts (daily average birch pollen counts>80 grains/m3), show that, on average, there is a peak between 1400 hours and 1600 hours. Back-trajectory analysis showed that, on days with high birch pollen counts (n=60), 80% of air masses arriving at the time of peak diurnal birch pollen count approached North London from the south in a 180 degree arc from due east to due west. Detailed investigations of three Betula pollen episodes, with distinctly different diurnal patterns compared to the mean daily cycle, were used to illustrate how night-time maxima (2200-0400 hours) in Betula pollen counts could be the result of transport from distant sources or long transport times caused by slow moving air masses. We conclude that the Betula pollen recorded in North London could originate from sources found to the west and south of the city and not just trees within London itself. Possible sources outside the city include Continental Europe and the Betula trees within the broad-leaved forests of Southern England.

  3. Newly discovered eclogite in the southern Appalachian orogen, northwestern North Carolina

    NASA Astrophysics Data System (ADS)

    Willard, R. A.; Adams, Mark G.

    1994-05-01

    Recent detailed geologic mapping in the Blue Ridge belt of northwestern North Carolina has revealed the first reported eclogite ( sensu stricto) in the southern Appalachian orogen. The eclogite occurs at the base of the Ashe Metamorphic Suite within a shear zone that separates the Spruce Pine thrust sheet from the underlying Grenville-age basement rocks. This contact juxtaposes rocks of apparent oceanic affinities (predominantly metapelite, metabasite, and meta-ultramafic rocks) with rocks of the ancient North American craton. The primary metamorphic assemblage in the eclogite is garnet + omphacite + quartz + rutile. Hornblende and plagioclase occur only as retrograde amphibolite facies phases in the eclogite. Pressure-temperature estimates for the primary eclogite assemblage are consistent with minimum pressures of 13-17 kbar at 625-790°C, while the retrograde amphibolite facies assemblage suggests conditions of 8.5-12 kbar and 650-730°C. Ultramafic blocks also occur within the shear zone containing the eclogite. The presence of high-pressure metamorphic rocks associated with ultramafic rocks and pelitic schists within a shear zone separating continental rocks from oceanic rocks is strong evidence for an ancient subduction event and indicates that at least part of the Ashe Metamorphic Suite is a subduction-related, accretionary mélange.

  4. Advection of North Atlantic Deep Water from the Labrador Sea to the southern hemisphere

    NASA Astrophysics Data System (ADS)

    Rhein, Monika; Kieke, Dagmar; Steinfeldt, Reiner

    2015-04-01

    Recently formed Labrador Seawater (LSW) and overflow water from Denmark Strait (DSOW) are main components of the Atlantic Meridional Overturning Circulation. Both exhibit a distinct chlorofluorocarbon (CFC) maximum. Here we use 25 years of CFC observations in the Atlantic to study the main features of the circulation of LSW and DSOW. From the CFC data, the age and fraction of young deep water are inferred. Due to the superior spatial data resolution compared to former attempts, regional differences in the spreading velocity and pathways of young deep water become evident, dependent on the regional circulation. The observed distributions of young LSW and DSOW showed that the DWBC is the fastest pathway to reach the southern hemisphere. The downstream decrease of the fractions of young LSW in the DWBC is slower compared to model studies. From 47°N to 42°N, DWBC transports of young LSW and DSOW decrease by 44% and 49%, respectively. At 26°N, the DWBC transport of young water is still 39% of the LSW formation rate and 44% of the DSOW overflow transport. Interior pathways also exist, especially in the subpolar North Atlantic and in the transition zone between the subpolar and subtropical gyre. Compared to DSOW, the distributions indicate a higher tendency for LSW to follow additional interior pathways. North of 45°N the major part of LSW is younger than 20 years. The general weakening of new LSW formation since the 1990s worked toward a homogenization between the LSW in the western and the eastern subpolar North Atlantic.

  5. Industrial-era lead and mercury contamination in southern Greenland implicates North American sources.

    PubMed

    Pérez-Rodríguez, Marta; Silva-Sánchez, Noemí; Kylander, Malin E; Bindler, Richard; Mighall, Tim M; Schofield, J Edward; Edwards, Kevin J; Martínez Cortizas, Antonio

    2017-09-21

    To study the long-range transport of atmospheric pollutants from lower latitude industrial areas to the Arctic, we analysed a peat core spanning the last ~700cal.yr (~1300-2000CE) from southern Greenland, an area sensitive to atmospheric pollution from North American and Eurasian sources. A previous investigation conducted in the same location recorded atmospheric lead (Pb) pollution after ~1845, with peak values recorded in the 1970s, and concluded that a North American source was most likely. To confirm the origin of the lead, we present new Pb isotope data from Sandhavn, together with a high-resolution record for mercury (Hg) deposition. Results demonstrate that the mercury accumulation rate has steadily increased since the beginning of the 19th century, with maximum values of 9.3μgm(-2)yr(-1) recorded ~1940. Lead isotopic ratios show two mixing lines: one which represents inputs from local and regional geogenic sources, and another that comprises regional geogenic and pollution sources. Detrending the Pb isotopic ratio record (thereby extracting the effect of the geogenic mixing) has enabled us to reconstruct a detailed chronology of metal pollution. The first sustained decrease in Pb isotope signals is recorded as beginning ~1740-1780 with the lowest values (indicating the highest pollution signature) dated to ~1960-1970. The (206)Pb/(207)Pb ratio of excess Pb (measuring 1.222, and reflecting pollution-generated Pb), when compared with the Pb isotopic composition of the Sandhavn peat record since the 19th century and the timing of Pb enrichments, clearly points to the dominance of pollution sources from North America, although it did not prove possible to further differentiate the emissions sources geographically. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. North American precipitation and temperature patterns associated with the El Nino/Southern Oscillation (ENSO)

    SciTech Connect

    Ropelewski, C.F.; Halpert, M.S.

    1986-01-01

    This paper describes an investigation of the typical North American precipitation and temperature patterns associated with the El Nino/Southern Oscillation (ENSO). Monthly composites, covering idealized two-year ENSO episodes, are computed at all stations with data spanning seven or more ENSO events. The first harmonic is extracted from the 24 monthly composite values and plotted in the form of a two-year harmonic dial vector. When plotted on a map of North America, these vectors reveal both the regions of coherent response and the phase of the response with respect to the evolution of the ENSO episode. Time series of temperature and precipitation for the regions identified in the harmonic vector maps are examined to determine the magnitudes of the responses and the percentage of the time that the identified response actually occurred in association with the ENSO events. The analysis shows that above normal precipitation was associated with ENSO in 18 out of 22 cases in the season starting with October of the ENSO year to March of the following year for an area of North America that includes parts of the southeastern US and northern Mexico. Above normal precipitation was also observed in the Great Basin area of the western US in 9 out of 11 cases for the April through October season during ENSO years. No high latitude precipitation signals were indicated by this analysis. Areas of Alaska and western Canada experienced positive temperature anomalies in 17 out of 21 ENSO episodes (81%) during the season defined by December of the ENSO year through the following March. Parts of the southeastern US near the Gulf of Mexico were found to have negative temperature anomalies associated with 20 out of 25 ENSO episodes for the season October of the ENSO year through the following March.

  7. Interannual sedimentary effluxes of alkalinity in the southern North Sea: Model results compared with summer observations.

    NASA Astrophysics Data System (ADS)

    Paetsch, Johannes; Kuehn, Wilfried; Six, Katharina

    2016-04-01

    Alkalinity generation in the sediment of the southern North Sea is the focus of several recent studies. One motivation for these efforts is the potentially enhanced buffering capacity of anthropogenic CO2 invasion into the corresponding pelagic system. An adaptation of a global multilayer sediment model (Heinze et al., 1999) in combination with a pelagic ecosystem model for shelf sea dynamics was used to study the benthic reactions on very different annual cycles (2001 - 2009) including the River Elbe summer flooding in 2002. The focus of this study is the efflux of alkalinity, their different contributors (aerobic respiration, denitrification, net sulfate reduction, calcite dissolution, nitrification) and their seasonal and interannual cycles. Similar to the observations covering the southern North Sea (Brenner et al., 2015) the model results show large horizontal gradients from the near-shore high productive areas with benthic remineralization up to Rmin = 10.6 mol C m-2 yr-1 and TA generation RTA = 2 mol C m-2 yr-1 to off-shore moderate productive areas with mean Rmin = 2.5 mol C m-2 yr-1 and mean TA generation RTA = 0.4 mol C m-2 yr-1. Beside calcite dissolution, aerobic respiration (producing ammonium) and denitrification are the largest contributors to alkalinity generation. Nitrification is reducing alkalinity in the sediment. Due to low regenerated primary production in summer, the year 2001 exhibits the lowest input of particulate organic matter into the sediment (POCexp=2.3 mol C m-2 yr-1), while the year 2003 exhibits the highest export production (POCexp=2.6 mol C m-2 yr-1). The biogeochemical reactions and the effluxes from the sediment follow these pelagic amplitudes with a time lag of about one year with damped amplitudes. References Brenner, H., Braeckman, U., Le Guitton, M., Meysman, F.J.R., 2015. The impact of sedimentary alkalinity release on the water column CO2 system in the North Sea. Biogeosiences Discussion, 12(15): 12395-12453. Heinze, C

  8. Pliocene palaeotemperature reconstruction for the southern North Sea Based on Ostracoda

    USGS Publications Warehouse

    Wood, A.M.; Whatley, R.C.; Cronin, T. M.; Holtz, T.

    1993-01-01

    The development of a large northeastern Atlantic shelf ostracod database has confirmed that an intrinsic relationship exists between watermass temperature and the spatial (latitudinal) distribution of benthonic shelf Ostracoda. A second Pliocene ostracod database, using assemblages from four boreholes in The Netherlands and a number of localities from the East Anglian Neogene succession has also been constructed. A quantitative method of modern analogues and the Squared Chord Distance dissimilarity coefficient has been employed as a means of calculating the level of similarity between Recent and Neogene assemblages and, therefore, to aid in the reconstruction of palaeotemperatures in the southern North Sea Basin during the Pliocene. The results, in the form of contoured dissimilarity values, indicate the presence of at least seven palaeoceanographical climatic phases between ca. 5.2 and 1.6 Ma BP. An early Pliocene cooling phase (ecozone A), in which the fauna is dominated by the cryophilic species; Palmenella limicola (Norman), Elofsonella concinna (Jones), Robertsonites tuberculatus (Sars), Neomonoceratina tsurugasakensis (Tabuki) and Acanthocythereis dunelmensis (Norman), supervenes a period of stable subtropical conditions in the Miocene. A 'mid' Pliocene warming phase (ecozone B), which has been documented throughout the North Atlantic, can be recognized in the faunal composition of the sublittoral ostracod assemblages of both The Netherlands and East Anglia. A hiatus between the Coralline and Waltonian crags is thought to be associated with a deterioration in climatic conditions. Recent analogues to The Netherlands faunas of ecozone C (first phase late Pliocene cooling, ca. 2.9 Ma BP) indicate a decrease of approximately 5-6??C in mean summer surface temperatures. A return to elevated temperatures, of a Mauritanian aspect, can be seen in the fauna of the FA2 zone and Waltonian Crag. This amelioration of climate occurred prior to the Praetiglian cold phase

  9. Pliocene palaeotemperature reconstruction for the southern North Sea Based on Ostracoda

    NASA Astrophysics Data System (ADS)

    Wood, A. M.; Whatley, R. C.; Cronin, T. M.; Holtz, T.

    The development of a large northeastern Atlantic shelf ostracod database has confirmed that an intrinsic relationship exists between watermass temperature and the spatial (latitudinal) distribution of benthonic shelf Ostracoda. A second Pliocene ostracod database, using assemblages from four boreholes in The Netherlands and a number of localities from the East Anglian Neogene succession has also been constructed. A quantitative method of modern analogues and the Squared Chord Distance dissimilarity coefficient has been employed as a means of calculating the level of similarity between Recent and Neogene assemblages and, therefore, to aid in the reconstruction of palaeotemperatures in the southern North Sea Basin during the Pliocene. The results, in the form of contoured dissimilarity values, indicate the presence of at least seven palaeoceanographical climatic phases between ca. 5.2 and 1.6 Ma BP. An early Pliocene cooling phase (ecozone A), in which the fauna is dominated by the cryophilic species; Palmenella limicola (Norman), Elofsonella concinna (Jones), Robertsonites tuberculatus (Sars), Neomonoceratina tsurugasakensis (Tabuki) and Acanthocythereis dunelmensis (Norman), supervenes a period of stable subtropical conditions in the Miocene. A 'mid' Pliocene warming phase (ecozone B), which has been documented throughout the North Atlantic, can be recognized in the faunal composition of the sublittoral ostracod assemblages of both The Netherlands and East Anglia. A hiatus between the Coralline and Waltonian crags is thought to be associated with a deterioration in climatic conditions. Recent analogues to The Netherlands faunas of ecozone C (first phase late Pliocene cooling, ca. 2.9 Ma BP) indicate a decrease of approximately 5-6°C in mean summer surface temperatures. A return to elevated temperatures, of a Mauritanian aspect, can be seen in the fauna of the FA2 zone and Waltonian Crag. This amelioration of climate occurred prior to the Praetiglian cold phase

  10. North Pacific Intermediate Water Circulation During Marine Isotope Stage 3: Southern California Margin

    NASA Astrophysics Data System (ADS)

    Murphy, D. P.; Thomas, D. J.

    2008-12-01

    Pleistocene-age sediments on the California margin preserve a detailed history of fluctuations in the intensity of the oxygen minimum zone (OMZ). Of particular interest is the pattern of millennial-scale (stadial- interstadial) changes in seafloor oxygen levels that characterize Marine Isotope Stage 3. Ocean Drilling Program Sites 893 and 1017 (595m and 955m) indicate a weakened OMZ during stadials (greater seafloor oxygenation) and a strong OMZ during interstadials (dysoxic seafloor conditions). Recent studies identified two hypotheses to explain the changes in seafloor oxygenation. The first invokes local increases in primary productivity. The alternative hypothesis suggests that changes in seafloor oxygenation resulted from switching the source of the water at intermediate depths. The inferred source of intermediate waters during interstadials is an older, oxygen-poor water mass from the southern high latitudes. During stadials the source switched to a young, oxygenated water mass derived from the north Pacific. However, traditional techniques are unable to distinguish between these two mechanisms (productivity vs. ocean circulation). To address the circulation hypothesis we generated a neodymium isotope record (143Nd/144Nd expressed as ɛ Nd) to reconstruct the composition of waters that reached the California margin. In the Pacific, waters from the north bear ɛ Nd values of ~-2, whereas waters from the south have values ~-7 to -9. We focus on the interval from 37-52ka, spanning interstadials 8-14. Samples from Sites 893 and 1017 were taken ~500 and ~750 years apart, respectively, to capture all interstadials and stadials. The ɛ Nd of the water mass bathing Sites 893 and 1017 did not change on a stadial-interstadial basis. Both sites also have values representative of invariant, southern sourced water masses (ɛ Nd = -9 and -7, respectively). This finding suggests that ocean circulation did not change on a millennial- scales supporting the hypothesis that

  11. Introducing mixotrophy into a biogeochemical model describing an eutrophied coastal ecosystem: The Southern North Sea

    NASA Astrophysics Data System (ADS)

    Ghyoot, Caroline; Lancelot, Christiane; Flynn, Kevin J.; Mitra, Aditee; Gypens, Nathalie

    2017-09-01

    Most biogeochemical/ecological models divide planktonic protists between phototrophs (phytoplankton) and heterotrophs (zooplankton). However, a large number of planktonic protists are able to combine several mechanisms of carbon and nutrient acquisition. Not representing these multiple mechanisms in biogeochemical/ecological models describing eutrophied coastal ecosystems can potentially lead to different conclusions regarding ecosystem functioning, especially regarding the success of harmful algae, which are often reported as mixotrophic. This modelling study investigates the implications for trophic dynamics of including 3 contrasting forms of mixotrophy, namely osmotrophy (using alkaline phosphatase activity, APA), non-constitutive mixotrophy (acquired phototrophy by microzooplankton) and also constitutive mixotrophy. The application is in the Southern North Sea, an ecosystem that faced, between 1985 and 2005, a significant increase in the nutrient supply N:P ratio (from 31 to 81 mol N:P). The comparison with a traditional model shows that, when the winter N:P ratio in the Southern North Sea is above 22 molN molP-1 (as occurred from mid-1990s), APA allows a 3-32% increase of annual gross primary production (GPP). In result of the higher GPP, the annual sedimentation increases as well as the bacterial production. By contrast, APA does not affect the export of matter to higher trophic levels because the increased GPP is mainly due to Phaeocystis colonies, which are not grazed by copepods. Under high irradiance, non-constitutive mixotrophy appreciably increases annual GPP, transfer to higher trophic levels, sedimentation, and nutrient remineralisation. In this ecosystem, non-constitutive mixotrophy is also observed to have an indirect stimulating effect on diatoms. Constitutive mixotrophy in nanoflagellates appears to have little influence on this ecosystem functioning. An important conclusion from this work is that contrasting forms of mixotrophy have different

  12. On the formation, ventilation, and erosion of mode waters in the North Atlantic and Southern Oceans

    NASA Astrophysics Data System (ADS)

    Trossman, D. S.; Thompson, L.; Mecking, S.; Warner, M. J.

    2012-09-01

    The mean residence times, subduction rates, and formation rates of Subtropical Mode Water (STMW) and Subpolar Mode Water (SPMW) in the North Atlantic and Subantarctic Mode Water (SAMW) in the Southern Ocean are estimated by combining a model and observations of chlorofluorocarbon-11 (CFC-11) via Bayesian Model Averaging (BMA), a statistical technique that weights model estimates according to how close they agree with observations. Subduction rates are estimated in two different ways to investigate the non-advective contribution to thermocline ventilation, which in turn are compared to formation rate estimates. One subduction rate estimate is based on entrainment/detrainment velocities and the other subduction rate estimate allows ventilation to be both an advective and diffusive process instead of a purely advective one by using transit-time distributions (TTDs). It is found that the subduction of all three mode waters is mostly an advective process, but up to about one-third of STMW subduction likely owes to non-advective processes. Also, while the formation of STMW is mostly due to subduction, the formation of SPMW is mostly due to other processes. About half of the formation of SAMW is due to subduction and half is due to other processes. A combination of air-sea flux, acting on relatively short timescales, and turbulent mixing, acting on a wide range of timescales, is likely the dominant SPMW erosion mechanism. Air-sea flux is likely responsible for most STMW erosion, and turbulent mixing is likely responsible for most SAMW erosion.

  13. Wave-Current Interactions in the Southern North Sea: The Impact on Salinity

    NASA Astrophysics Data System (ADS)

    Stanev, Emil; Grashorn, Sebastian

    2017-04-01

    The interplay between wind waves and currents in the coastal zone of southern North Sea along with the resulting changes in the salinity distribution there are quantified using simulations with the unstructured-grid ocean model SCHISM coupled with the wind wave model WWM. The wave-induced transport of salt leads to changes in the horizontal salinity distribution. These are most pronounced in front of barrier islands where coherent patterns caused by the coupling between tides, surface drift and wind waves reveal salinity changes up to 0.5. The weak stratification dominating the patterns of salinity in the coastal zone is mostly destroyed by wind waves. Thus, effects created by wind waves tend to substantially modify the estuarine circulation. An explanation of these important processes in the coastal zone has been given based on analysis of ratio between significant wave height and tidal range. This control-parameter, which is relatively small under mild weather conditions, can exceed under strong-wind condition 1 in the coastal zone, thus mixing due to waves becomes dominant. The effect of fresh water fluxes from subterranean estuaries is relatively small and confined only in the vicinity of corresponding sources.

  14. On the ecology of the dragonet Callionymus lyra L. in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Van Der Veer, H. W.; Creutzberg, F.; Dapper, R.; Duineveld, G. C. A.; Fonds, M.; Kuipers, B. R.; Van Noort, G. J.; Witte, J. I. J.

    The present paper evaluates data collected in the southern North Sea between 1972 and 1984 on geographical distribution, density, growth, mortality, biomass, production and food requirements of the dragonet Callionymus lyra L. Catches never exceeded 1500 individuals per 10 000 m 2 and the dragonet showed a clear pattern of abundance with highest densities in the coastal zone and decreasing numbers going offshore. Mortality rates appeared to be rather constant over the age groups with z = 0.55 y -1. The dragonet population mainly consisted of 1, 2 and 3-year-old individuals with a mean length at the end of the year of 7.5, 15 and 19 cm, respectively. Production values were at least 159 g AFDW·10 000 m -2·y -1. Predation pressure exerted by the dragonets amounted to at least 795 g AFDW·10 000 m -2·y -1. The correspondence between the von Bertalanffy growth curve in this study and that of 1948 ( CHANG, 1951) suggests absence of effects of eutrophication in the area on the growth of dragonets between 1948 and 1980s. The main difference with 1948 was the absence of large individuals, probably as a result of increased fishery in the area.

  15. Generation of seiches by cold fronts over the southern North Sea

    NASA Astrophysics Data System (ADS)

    de Jong, M. P. C.; Holthuijsen, L. H.; Battjes, J. A.

    2003-04-01

    Seiches affecting the Port of Rotterdam are generated in the Southern North Sea. Their generation is investigated with observations and numerical simulations. A wavelet analysis of the observations, both at sea and in the harbor, shows that low-frequency energy (0.1-2.0 mHz) does indeed occur at sea prior to each seiche event in Rotterdam. An analysis of 6 years of weather charts indicates that all 51 seiche events in this period (with amplitude exceeding 0.25 m) coincided with the passage of a low-pressure weather system. Some of these low-pressure systems included a sharp cold front (classical or ana), whereas others included a more diffuse cold front (split or kata). Numerical simulations with a hydrodynamic model driven by meteorological observations reproduced the seiches for situations with the sharp cold fronts correctly. The seiches that were simulated for situations with the gradual cold fronts do not agree with the observations, which is ascribed to the inadequate atmospheric forcing of the hydrodynamical model.

  16. Grassland vegetation and bird communities in the southern Great Plains of North America

    USGS Publications Warehouse

    Chapman, R.N.; Engle, David M.; Masters, R.E.; Leslie, David M.

    2004-01-01

    Structure and composition of vegetation and abundance of breeding birds in grasslands seeded to Old World bluestem (Bothriochloa ischmaeum) were compared to native mixed prairie in the southern Great Plains of North America. Abundance of birds was determined using fixed-radius point counts. Detrended correspondence analysis was used to compare plant community composition and canonical correspondence analysis was used to examine the relationships between plant species composition and vegetation structure with the bird community. Plant species composition differed distinctly between seeded grassland and native mixed prairie, but the differences were not reflected in habitat structure, bird community composition, or abundance of bird species. Seeded grassland was inferior to native mixed prairie in terms of diversity of plant species, but that difference did not translate into meaningful differences in structure that drove habitat selection by breeding birds. Conservation programs that promote establishment of seeded grassland and do not allow for suitable disturbance regimes will selectively benefit a narrow suite of birds regardless of plant species composition. ?? 2004 Elsevier B.V. All rights reserved.

  17. Late Holocene saltmarsh accretion among sand ridges, West Bay, southern Pamlico Sound, North Carolina

    NASA Astrophysics Data System (ADS)

    Barber, D. C.; Woodson, A. L.; Newbern, E. H.

    2011-12-01

    The ongoing Late Holocene sea-level rise has inundated a series of low (< 2m above sea level) relict sand ridges on Cedar Island, in southern Pamlico Sound on the central North Carolina coast (35.00°N, 76.34°W). The ridges likely represent shorelines formed during a previous (Pleistocene) sea-level highstand by a combination of longshore transport and eolian dune processes. Saltmarsh peat comprising primarily the remains of the high marsh plant Juncus gerardii has accumulated between the ridges, yielding a continuous record of transgression over at least the last 2,000 years. The protected depositional setting between the ridges, the small tidal amplitude (< 25 cm) in southern Pamlico Sound, and the smoothly varying topography of the underlying sand surface provide the opportunity to acquire basal saltmarsh peat samples from a range of elevations for sea-level reconstruction. We obtained cores of the marsh peat and sand deposits using various techniques (hand auger, Russian and dutch peat corers, vibracore) to generate an overview of the stratigraphy in the study area. We visually logged the cores and analyzed samples for organic carbon content, particle size and magnetic susceptibility. In the marsh peat, plant macrofossils were identified and agglutinated foraminiferal assemblages were counted. Saltmarsh foraminifera species identified in the cores include Trochammina inflata, Ammoastuta inepta, Jadammina macrescens, Tiphotroca comprimata and Milliamina fusca. Radiocarbon dates on plant material provide chronological control. Marsh core elevations were referenced to NAVD88 by total station surveys to the NGS benchmark on Cedar Island. We have acquired marsh cores as deep as 3.25 m below local mean sea level (MSL), but thus far the deepest saltmarsh peat sample found to contain saltmarsh foraminifera is from 2.16 m below MSL. The marsh deposits are laterally consistent in the upper 1.5 m of core transects, but minor downcore variations in organic content

  18. Remotely sensed seasonality in the spatial distribution of sea-surface suspended particulate matter in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Eleveld, Marieke A.; Pasterkamp, Reinold; van der Woerd, Hendrik J.; Pietrzak, Julie D.

    2008-10-01

    An algorithm is presented for estimating near-surface SPM concentrations in the turbid Case 2 waters of the southern North Sea. The single band algorithm, named POWERS, was derived by parameterising Gordon's approximation of the radiative transfer model with measurements of Belgian and Dutch inherent optical properties. The algorithm was used to calculate near-surface SPM concentration from 491 SeaWiFS datasets for 2001. It was shown to be a robust algorithm for estimating SPM in the southern North Sea. Regression of annual geometric mean SPM concentration derived from remote sensing (SPM rs), against in situ (SPM is) data from 19 Dutch monitoring stations was highly significant with an r2 of 0.87. Further comparison and statistical testing against independent datasets for 2000 confirmed the consistency of this relationship. Moreover, time series of SPM rs concentrations derived from the POWERS algorithm, were shown to follow the same temporal trends as individual SPM is data recorded during 2001. Composites of annual, winter and summer SPM rs for 2001 highlight the three dominant water masses in the southern North Sea, as well as their winter-fall and spring-summer variability. The results indicate that wind induced wave action and mixing cause high surface SPM signals in winter in regions where the water column becomes well mixed, whereas in summer stratification leads to a lower SPM surface signal. The presented algorithm gives accurate near-surface SPM concentrations and could easily be adapted for other water masses and seas.

  19. PCDDs, PCDFs, and coplanar PCBs in albatross from the North Pacific and Southern Oceans: levels, patterns, and toxicological implications.

    PubMed

    Tanabe, Shinsuke; Watanabe, Mafumi; Minh, Tu Binh; Kunisue, Tatsuya; Nakanishi, Shigeyuki; Ono, Hitoshi; Tanaka, Hiroyuki

    2004-01-15

    Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (coplanar PCBs) were determined in five albatross species collected from the North Pacific and Southern Oceans to assess the north-south differences in residue levels, accumulation patterns, and toxic potential. Black-footed and Laysan albatrosses from the North Pacific Ocean contained higher levels of PCDD/Fs and coplanar PCBs than albatrosses from the Southern Ocean, indicating that emission sources of these contaminants were predominant in the northern hemisphere. Residue levels in albatrosses from the remote North Pacific Ocean far from the point source of pollution were comparable to or higher than those in terrestrial and coastal birds from contaminated areas in developed nations, suggesting the specific exposure and accumulation of PCDD/Fs and coplanar PCBs in albatross. The long life span and ingestion of plastic resin pellets by albatrosses could be the plausible explanations for the elevated accumulation of persistent and lipophilic contaminants including PCDD/Fs and coplanar PCBs in these birds. Relative proportions of PCDFs and coplanar PCBs in albatross were higher than those observed in birds inhabiting terrestrial and coastal areas, suggesting that these toxic chemicals may have higher transportability by air and water than PCDDs. Congener patterns of PCDD/Fs in albatross showed less variability as compared to those in terrestrial species, indicating that contamination patterns of PCDD/Fs were similar within the open ocean environment. Contributions of PCDD/Fs to total TEQs in albatrosses from the open ocean were generally lower than those in terrestrial birds, suggesting different toxic potency of PCDD/Fs and coplanar PCBs on animals inhabiting open ocean and terrestrial environment. Whereas albatrosses from southern oceans retained lower TEQ concentrations, possible adverse effects of PCDD/Fs and coplanar PCBs

  20. Depth averaged wave-current interaction in the multi bank morphology of the southern North Sea

    NASA Astrophysics Data System (ADS)

    Komijani, Homayoon; Osuna, Pedro; Ocampo Torres, Francisco; Monbaliu, Jaak

    2017-04-01

    The effects of wind induced waves on the barotropic mean flow during a storm event in the southern North Sea are investigated. The well known radiation stress gradient theory of Longuet-Higgins and Stewart (1962, 1964) together with the influence of waves through the Stokes drift (Hasselmann, 1971 and Garret, 1976) are incorporated in the RANS equation system of the COHERENS circulation model (Luyten et al., 2005) following the methodology worked out by Bennis et al. (2011) . The SWAN spectral wave model (version 40.91, http://www.swan.tudelft.nl/) is used to provide the wave information. This allows us to take into account the dissipative terms of wave momentum flux to the mean flow such as depth induced wave breaking and bottom friction as well as the conservative terms of wave effects such as the vortex-force and wave induced pressure gradient. The resulting coupled COHERENS-SWAN model has been validated using the well known planar beach test case proposed by Haas and Warner (2009) in depth averaged mode. For the application in the southern North Sea, a series of nested grids using COHERENS (circulation model) and WAM cycle 4.5.3 (spectral wave model applied to the North Sea shelf area, Monbaliu et al. 2000; Günther, H. and A. Behrens, personal communications, May 2012) is set up to provide the hydrodynamic and wave boundary conditions for the COHERENS-SWAN two way coupled wave-current model for the Belgian coastal zone model. The improvements obtained in hindcasting the circulation processes in the Belgian coastal area during a storm event will be highlighted. But also difficulties faced in the coupling of the models and in the simulation of a real case storm will be discussed. In particular, some of the approaches for dealing with the numerical instabilities due to multi bank morphology of the southern North Sea will be addressed. References : Bennis, A.-C., F. Ardhuin, and F. Dumas (2011). "On the coupling of wave and three-dimensional circulation models

  1. Evidence for early Pennsylvanian faulting in eastern Kentucky coalfield

    SciTech Connect

    Greb, S.F.; Chesnut, D.R. Jr.; Davidson, O.B.; Rodriguez, R. )

    1989-08-01

    A series of sedimentary features including a mass-flow deposit and contorted pseudo-nodule layers at approximately the same stratigraphic horizon on the eastern, downthrown block of a normal fault system along the Rockcastle River in the Eastern Kentucky coalfield indicate that the fault was active during deposition of the Lee sandstone. The rarity of mass flows in this part of the section, a change in paleocurrents compared with surrounding units, the abundant shale clasts indicating short transport distance, and the detrital siderite clasts within the flow that are abundant on the upthrown block of the fault and not in underlying sandstones on the downthrown block of the fault indicate that movement along the fault provided an upthrown source of sideritic shales and may have triggered the mass flow. Several areas of slumping and contorted bedding also occur on the downthrown side of the fault. Of particular interest are two shaly units containing isolated and contorted sandstone pseudonodules or pillows. The sandstones are tightly folded but exhibit no apparent preferred orientation of folding or horizontal translation. These deposits are also unique to this area in the coalfield and coupled with their location near the fault may indicate that liquefaction of sand and shale layers was the result of seismic energy from the nearby fault.

  2. Investigation of the Jharia coalfield mine fires - India

    SciTech Connect

    Michalski, S.R.; Custer, E.S. Jr.; Munshi, P.L.

    1997-12-31

    In 1971, the Indian coal industry was nationalized and Bharat Coking Coal Limited was formed. The new company inherited about 600 poorly operated collieries, many on fire. Efforts to extinguish the fires have been partially successful. About sixty-five fires continue to burn in the 450-sq.km. coalfield. This is the largest complex of above and underground coal fires in the world. The fires have spread and grown to affect coal production, the environment and the health, safety, and well being of one million people living in the region. A 21-month long, two-part study, funded by the World Bank, began in 1994 and was completed in 1996. Part one was an analysis of the fires which included, their location, size, impact on the community, physical environment and coal reserves and possible remediation measures and their cost. Part two included an environmental and socioeconomic survey of the coalfield and environs and the impact of implementing remediation measures. The investigations included the use of satellite and airborne remote sensing platforms, a Global Positioning System for surveying, drilling, software for mine planning and development, a field reconnaissance, laboratory testing, review of colliery records and data analysis. A counterpart staff of Indian professionals worked with the expatriates to acquire the training, procedures and methodologies required to continue the work. Technologies for extinguishing, containing and preventing fires and their cost were identified. Recommendations were made to extinguish or contain the fires.

  3. Storm impacts and shoreline recovery: Mechanisms and controls in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Brooks, S. M.; Spencer, T.; Christie, E. K.

    2017-04-01

    Storm impacts play a significant role in shoreline dynamics on barrier coastlines. Furthermore, inter-storm recovery is a key parameter determining long-term coastal resilience to climate change, storminess variability and sea level rise. Over the last decade, four extreme storms, with strong energetic waves and high still water levels resulting from high spring tides and large skew surge residuals, have impacted the shoreline of the southern North Sea. The 5th December 2013 storm, with the highest run-up levels recorded in the last 60 years, resulted in large sections of the frontline of the North Norfolk coast being translated inland by over 10 m. Storms in March and November 2007 also generated barrier scarping and shoreline retreat, although not on the scale of 2013. Between 2008 and 2013, a calm period, recovery dominated barrier position and elevation but was spatially differentiated alongshore. For one study area, Scolt Head Island, no recovery was seen; this section of the coast is being reset episodically landwards during storms. By contrast, the study area at Holkham Bay showed considerable recovery between 2008 and 2013, with barrier sections developing seaward through foredune recovery. The third study area, Brancaster Bay, showed partial recovery in barrier location and elevation. Results suggest that recovery is promoted by high sediment supply and onshore intertidal bar migration, at rates of 40 m a- 1. These processes bring sand to elevations where substrate drying enables aeolian processes to entrain and transport sand from upper foreshores to foredunes. We identify three potential sediment transport pathways that create a region of positive diffusivity at Holkham Bay. During calm periods, a general westward movement of sediment from the drift divide at Sheringham sources the intertidal bar and foredune development at Holkham Bay. However, during and following storms the drift switches to eastward, not only on the beach itself but also below the

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  5. Potential field modelling of the Baltica Avalonia (Thor Tornquist) suture beneath the southern North Sea

    NASA Astrophysics Data System (ADS)

    Williamson, J. P.; Pharaoh, T. C.; Banka, D.; Thybo, H.; Laigle, M.; Lee, M. K.

    2002-12-01

    Magnetic anomaly maps of the Trans-European Suture Zone (TESZ) highlight the contrast between the highly magnetic crust of Baltica and the less magnetic terranes to the SW of the suture. Although the TESZ is imaged on gravity maps, anomalies related to postcollisional rifting and reactivated rift structures tend to dominate. Seismic and potential field data have been used to construct 2 {1}/{2}-D crustal models along three profiles crossing the Baltica-Avalonia suture in the southern North Sea (SNS). The first of these models lies along a transect assembled from reflection line GECO SNST 83-07 and refraction profile EUGENO-S 2; the other two models are coincident with MONA LISA profiles 1 and 2. Additional structural information and density information for the cover sequence is available from released wells, while magnetic susceptibility values are compatible with values measured from borehole core samples. Magnetic anomalies related to the suture are interpreted as due to magnetic Baltican basement of the Ringkøbing-Fyn High dipping SW beneath nonmagnetic Avalonian basement underlying the western part of the SNS. Low-amplitude, long-wavelength magnetic anomalies occurring outboard of the suture are interpreted as due to a mid-crustal magnetic body, possibly a buried magmatic complex. This might represent the 'missing' arc related to inferred southward subduction of the Tornquist Sea, or an exotic element emplaced during the collision between Avalonia and Baltica. The present model supports an imbricated structure within Baltica as indicated by the latest reprocessing of the MONA LISA seismic data.

  6. Water footprint of crop production for different crop structures in the Hebei southern plain, North China

    NASA Astrophysics Data System (ADS)

    Chu, Yingmin; Shen, Yanjun; Yuan, Zaijian

    2017-06-01

    The North China Plain (NCP) has a serious shortage of freshwater resources, and crop production consumes approximately 75 % of the region's water. To estimate water consumption of different crops and crop structures in the NCP, the Hebei southern plain (HSP) was selected as a study area, as it is a typical region of groundwater overdraft in the NCP. In this study, the water footprint (WF) of crop production, comprised of green, blue and grey water footprints, and its annual variation were analyzed. The results demonstrated the following: (1) the WF from the production of main crops was 41.8 km3 in 2012. Winter wheat, summer maize and vegetables were the top water-consuming crops in the HSP. The water footprint intensity (WFI) of cotton was the largest, and for vegetables, it was the smallest; (2) the total WF, WFblue, WFgreen and WFgrey for 13 years (2000-2012) of crop production were 604.8, 288.5, 141.3 and 175.0 km3, respectively, with an annual downtrend from 2000 to 2012; (3) winter wheat, summer maize and vegetables consumed the most groundwater, and their blue water footprint (WFblue) accounted for 74.2 % of the total WFblue in the HSP; (4) the crop structure scenarios analysis indicated that, with approximately 20 % of arable land cultivated with winter wheat-summer maize in rotation, 38.99 % spring maize, 10 % vegetables and 10 % fruiters, a sustainable utilization of groundwater resources can be promoted, and a sufficient supply of food, including vegetables and fruits, can be ensured in the HSP.

  7. Wave-current interactions in the southern North Sea: The impact on salinity

    NASA Astrophysics Data System (ADS)

    Schloen, Julia; Stanev, Emil V.; Grashorn, Sebastian

    2017-03-01

    The interplay between wind waves and currents in the coastal zone of the southern North Sea along with the resulting changes in the salinity distribution are quantified using simulations with the unstructured-grid ocean model SCHISM coupled with the wind wave model WWM III. Several sensitivity runs, which are carried out to estimate the individual contributions of different physical mechanisms and forcing, demonstrated that the density gradients in the coastal zone reduce tidal current by 18%, whereas the wind waves enhance the circulation in some cases. The latter happens when along-shore wind speed approaches ∼10 m s-1 resulting in long-shore currents following the western Dutch coast and the German Wadden Sea islands. The wave-induced transport of salt leads to changes in the horizontal salinity distribution. These are most pronounced in front of barrier islands where coherent patterns caused by the coupling between tides, surface drift, and wind waves reveal salinity changes up to 0.5. The weak stratification of salinity in the coastal zone is mostly destroyed by wind waves. Thus, effects created by wind waves tend to substantially modify the estuarine circulation. An explanation of these important processes in the coastal zone has been given based on an analysis of the ratio between significant wave height and tidal range. This control-parameter, which is relatively small under mild weather conditions, can exceed unity under strong wind conditions in the coastal zone, thus mixing due to waves becomes dominant. The effect of fresh water fluxes from subterranean estuaries is relatively small and confined only in the vicinity of corresponding sources.

  8. Drug-resistant Trypanosoma congolense in naturally infected donkeys in north Omo Zone, southern Ethiopia.

    PubMed

    Assefa, E; Abebe, G

    2001-08-31

    A three-part study was conducted to determine the efficacy of isometamidium chloride in donkey populations naturally infected with trypanosomes in north Omo Zone, southern Ethiopia. In the first, 373 randomly selected donkeys from four villages were examined for trypanosome infections by the dark ground/phase contrast buffy coat technique (BCT) in November 1999. The trypanosome prevalence was 18.2% (95% confidence interval (CI): 14.4, 22.5) and Trypanosoma congolense was the most common species accounting for 66.2% of the overall infections. In the second part, 40 infected donkeys were selected and treated with a prophylactic dose of 1.0mg/kg of isometamidium chloride and thereafter monitored every 14 days for 90 days. Trypanosomes were detected in eight donkeys within 1 month and in 20 donkeys within 2 months of treatment. About 16% (5/32) of donkeys infected with T. congolense were detected parasitemic 1 month after treatment. In addition, the result also revealed that all relapse/breakthrough infections were due to T. congolense. In the third part of this study mice were infected with two T. congolense field isolates from donkeys that were found to be parasitemic within 1 or 2 months after isometamidium treatment. The mice were treated with ranges of doses of isometamidium chloride or diminazene aceturate and thereafter followed for relapse infection. Isometamidium chloride at doses 0.5-4 mg/kg body weight and diminazene aceturate at doses of 3.5-28 mg/kg body weight failed completely to cure T. congolense infections in any of the mice.

  9. Chemostratigraphic Constraints on Late Jurassic Paleoceanography of the East Texas Basin, Southern Margin of North America

    NASA Astrophysics Data System (ADS)

    Mainali, P.; Rowe, H. D.

    2010-12-01

    Late Jurassic deposition of organic-rich muds occurred in the East Texas Basin of modern-day Texas and Louisiana in a ramp-style marine setting during the early formation of the Gulf of Mexico. These mudrocks are regional known as the Haynesville and Bossier Formations. The goals of the current project are to 1) develop a better understanding of the paleoceanographic conditions and the depositional environment, and 2) develop linkages between the record from the southern margin of North America and other well-documented paleoceanographic records of Kimmeridgian age. Ten drill cores from the study area have been studied for their geochemistry. Each core was scanned at a 1-foot interval using a handheld x-ray fluorescence instrument, providing rapid, quantitative analysis of the following elemental concentrations: Mg, Al, S, Si, P, K, Ti, Ca, Mn, Fe, Mo, Cr, Ni, Cu, Zn, Th, Rb, U, Sr, Zr, and V. In addition, preliminary interpretations for total inorganic carbon (TIC), total organic carbon (TOC), total nitrogen (%N), and bulk rock TOC and N isotopic composition of core samples reveal distinct differences between the Bossier and Haynesville formations. Results from previous geochemical studies suggest that the siliciclastic-dominated Bossier formation has less TOC than the underlying Haynesville formation. Furthermore, the Haynesville is much more carbonate-rich (calcite) than the overlying Bossier. An upwardly increasing trend in Si/Al in some cores suggests increasing detrital quartz influx. A linear relationship between Fe and Al suggest that iron is primarily in clay mineral phases in the Haynesville. Enrichments in Mo concentrations and Cr/V ratios reveal periods of anoxic conditions.

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

    PubMed

    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.

  11. A hydrographic time series station in the Wadden Sea (southern North Sea)

    NASA Astrophysics Data System (ADS)

    Reuter, Rainer; Badewien, Thomas H.; Bartholomä, Alexander; Braun, Axel; Lübben, Andrea; Rullkötter, Jürgen

    2009-04-01

    In the tidal inlet between the East Frisian islands of Langeoog and Spiekeroog, southern North Sea, a time-series station was set up in autumn 2002 as part of the research programme BioGeoChemistry of Tidal Flats run by the University of Oldenburg. The purpose of the station is to provide continuous data on physical, biological and chemical parameters. In addition to instruments recording basic hydrographic and meteorological parameters, the time-series station is equipped with acoustic Doppler profilers for measuring surface waves and current profiles. Compact optical spectrometers are being used for spectral measurements of seawater transmission and for daylight reflectance. Additional sensors were installed for measuring oxygen, nutrients and methane in the seawater. The data shall help to quantify the flux of dissolved and suspended matter between the backbarrier tidal flat and the open sea and to characterise the material transformation in the tidal flat area by biogeochemical processes over the tidal cycle. Due to its novel design, operation of the station is also possible during winter and under extreme weather conditions (gales, storm surges, and sea ice) when data sampling with conventional platforms such as research vessels, buoys, or smaller poles could not be performed in the past. In this way, time series of data are obtained, which include events that are most relevant to the evolution of this coastal area. The performance of the station and its equipment are presented with data covering 6 years of operation. Time series of air and water temperature as well as seawater salinity demonstrate the multiyear dynamics of these parameters in the East Frisian Wadden Sea. Hydrographic data collected under specific meteorological conditions such as gales and storm surges exemplify the all-weather capabilities of the station and its value for studying hydrographic processes in the Wadden Sea.

  12. Slylab (SL)-3 View - North Central Wyoming (WY) - Southern Montana (MT)

    NASA Image and Video Library

    1973-08-15

    S73-35081 (July-September 1973) --- A view of approximately 3,600 square miles of north central Wyoming and southern Montana is seen in this Skylab 3 Earth Resources Experiments Package S190-B (five-inch Earth terrain camera) photograph taken from the Skylab space station in Earth orbit. The Big Horn River following northward crosses between the northwest trending Big Horn Mountains and the Pryor Mountains. Yellowtail Reservoir, named after a former chief of the Crow Indian tribe in the center of the picture is impounded by a dam across the small rectangular crop area along the Big Horn River (upper right) and the strip farming (yellow) practiced on the rolling hill along the Big Horn River and its tributaries (upper left corner and right edge). The low sun angle enhances the structural features of the mountains as well as the drainage patterns in the adjacent basins. Rock formation appears in this color photograph as they would to the eye from this altitude. The distinctive redbeds can be traced along the front of the Pryor Mountains and indicate the folding that occurred during mountain building. EREP investigators, Dr. Houston of the University of Wyoming and Dr. Hoppin of the University of Iowa, will analyze the photograph and use the results in geological mapping and mineral resource studies. Lowell, Wyoming (lower left corner) and Hardin, Montana (upper right corner) can be recognized. Federal agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce, Interior, the Environmental Protection Agency and the Corps of Engineers. All EREP photography is available to the public through the Department of Interior?s Earth Resources Observations Systems Data Center, Sioux Falls, South Dakota, 57198. (Alternate number SL3-86-337) Photo credit: NASA

  13. Participatory planning in river catchments, an innovative toolkit tested in Southern Africa and North West England.

    PubMed

    Tippett, J

    2005-01-01

    The European Union Water Framework Directive (WFD) offers an unparalleled opportunity for improving river basin management. Active participation is essential for its delivery. "End-of-pipe" solutions will not deliver the improvements needed to achieve its ambitious goals. This research tested DesignWays, a toolkit for participatory planning, as a mechanism for maximizing the long-term social and environmental benefits of such stakeholder and community participation. It examined the emerging role of "planning for sustainability" in the context of river catchments. Sustainable management of water requires integration, and recognition of interconnections between systems at different levels of scale. This is an endeavour in which systems thinking provides useful tools. The development of DesignWays was a conscious attempt to embed 'new paradigm' living systems metaphors into a practical planning tool. This paper begins with a description of DesignWays and its development in Southern Africa. An outline of the context of the action research in North-West England is followed by a description of the stages of the process, with highlights of the outcomes. This research had two major outcomes: a contribution to theory through an in-depth exploration of the theoretical basis of participatory, ecologically informed design; and a contribution to practice through investigating DesignWays' potential to meet key challenges of the WFD. This research points to the importance of understanding participatory planning as a societal process, aiming to make the process engaging and meaningful. It has pointed to the need to see participatory planning and education for sustainability as an integrated process. It demonstrated the benefits of an iterative process in which planning at the landscape level of scale informs, and is informed by, work at the site level. It has shown that an approach consistent with a living systems paradigm can contribute to the development of more integrated

  14. A discovery of extremely-enriched boehmite from coal in the Junger Coalfield, the northeastern Ordos Basin

    USGS Publications Warehouse

    Dai, S.; Ren, D.; Li, S.; Chou, C.

    2006-01-01

    The authors found an extremely-enriched boehmite and its associated minerals for the first time in the super-thick No. 6 coal seam from the Junger Coalfield in the northeastern Ordos Basin by using technologies including the X-ray diffraction analysis (XRD), scanning electron microscope equipped with an energy dispersive X-ray spectrometer, and optical microscope. The content of boehmite is as high as 13.1%, and the associated minerals are goyazite, zircon, rutile, goethite, galena, clausthalite, and selenio-galena. The heavy minerals assemblage is similar to that in the bauxite of the Benxi Formation from North China. The high boehmite in coal is mainly from weathering crust bauxite of the Benxi Formation from the northeastern coal-accumulation basin. The gibbsite colloidstone solution was removed from bauxite to the peat mire, and boehmite was formed via compaction and dehydration of gibbsite colloidstone solution in the period of peat accumulation and early period of diagenesis.

  15. Relationship between Precambrian North Korean Peninsula and the North China Craton: Evidence from LA-ICP-MS U-Pb ages of detrital zircons from Neoproterozoic tillites of North Korea and Southern North China Craton

    NASA Astrophysics Data System (ADS)

    Hu, B.; Zhai, M.; Peng, P.; Zhang, Y.; Wu, J.; Jia, X.; Zhang, H.; Lei, W.; Zhuang, G.

    2016-12-01

    Relationship between Precambrian Korean Peninsula and the North China Craton (NCC) is focus of attention. There are Neoproterozoic tillites in Phyongnam Basin, Nangrim massif, North Korea (NK) and Southern NCC. Nangrim massif was regarded as a part of the NCC according to similar Precambrian basements between Nangrim massif and Longgang massif in the Northeast NCC. But the comparation of Neoproterozoic rocks is lacked between NK and NCC. Detrital zircon LA-ICP-MS U-Pb ages of 2 pebbly phyllite samples of Pirangdong Series in Phyongnam Basin and 2 argillaceous cemented mix-conglomeate samples of Luoquan Series in Southern NCC was analyzed in this research. Detrital zircon ages of pebbly phyllites of Pirangdong Series distribute mainly at 1.85 Ga, 1.8 Ga, 1.6 Ga, 1.4 Ga and 1.2 Ga. A small number of them are at 3.2 Ga, 2.6 - 2.5 Ga, 2.3 Ga, 2.1 Ga and 900 - 860 Ma. Detrital zircon ages of mix-conglomeates of Luoquan Series mainly focus on 2.5 Ga, 2.2 Ga, 2.0 Ga, 1.8 Ga and 1.6 Ga. Minor of them distribute at 1.12 Ga. The similar age distribution of Pirangdong and Luoquan Series of 2.6 - 2.5 Ga, 2.1 - 2.0 Ga, 1.85 - 1.8 Ga and 1.6 Ga corresponds to Precambrian significant tectonic- magmatic- thermal events of the NCC, which indicates that the Precambrian basement rocks of the NCC are main provenances of both Pirangdong and Luoquan Series. This also confirm that the Phyongnam Basin is a part of Neoproterozoic sedimentary covers of the NCC. It is worth to mention that 1.2 - 1.0 Ga and 900 - 850 Ma magmatic rocks in the NCC are seldom reported which relate to the assemblage and breakup of Rodinia Supercontinent. whereas they crop out widely in the South China Craton (SCC) and was always regarded as a mark distingusing the two craton. 1.2 - 1.0 Ga and 900 - 850 Ma zircon ages preserved in sedimentary rocks not only in North Korea and Southern NCC but also in Northeast NCC and East NCC provide data to compare Neoproterozoic strata between NCC and SCC and important clues to

  16. Geology of the fushun coalfield, Liaoning Province, People's Republic of China

    USGS Publications Warehouse

    Johnson, E.A.

    1990-01-01

    The Fushun coalfield is located in Liaoning Province 45 km east of Shenyang in a relatively small east-west-trending exposure of Mesozoic and Cenozoic rocks surrounded by Precambrian terrane. The coal is included in a sequence of early Tertiary rocks consisting of Paleocene basalt and tuff, and Eocene coal, oil shale and mudstone. These units have been folded into a syncline that plunges gently to the east. The overturned north limb of this fold has been partly removed by a thrust fault. The principal coal beds are low-sulfur subbituminous and bituminous in rank, are of limnic origin, and are contained in the 55-m-thick Eocene Guchengzi Formation. The field, which has been active since the turn of the century, has both open pit and underground mines. The largest operation is the West Open Pit mine, which measures 2.0 km wide, 6.6 km long, and 300 m deep. Coal is mined by means of power shovels, trucks, and an electric rail system. Oil shale from the Eocene Jijuntun Formation is also mined. ?? 1990.

  17. Making a World of Difference. Dimension: Language '91. Selected Papers from the Joint Meeting of the Southern Conference on Language Teaching and the Foreign Language Association of North Carolina (Research Triangle Park, North Carolina, 1991).

    ERIC Educational Resources Information Center

    Terry, Robert M., Ed.

    Papers from the 1991 joint Southern Conference on Language Teaching (SCOLT)/ Foreign Language Association of North Carolina (FLANC) conference are presented. Because the state of North Carolina is in the forefront of state-mandated foreign language education in the elementary schools (FLES), 4 of the 10 articles in this volume address FLES…

  18. A recovery of harbour porpoises ( Phocoena phocoena) in the southern North Sea? A case study off Eastern Frisia, Germany

    NASA Astrophysics Data System (ADS)

    Thomsen, Frank; Laczny, Martin; Piper, Werner

    2006-09-01

    Detailed information on year-round distribution, seasonal abundance and inter-annual trends of a given species is essential for any conservation effort. However, for most odontocetes this knowledge is rather limited. Therefore, area-specific management or conservation plans are often difficult to argue for. This is also true for the harbour porpoise ( Phocoena phocoena), although it is the most common cetacean species in the North Sea. Knowledge of the current status of local stocks as well as fine scale information on the temporal use of certain areas by the species is incomplete. One area of concern is the southern North Sea where the abundance of harbour porpoises has declined in the twentieth century. Recent studies using stranding data and observations from seabird surveys indicate a comeback of the species along the Dutch and Belgian coast. However, data on other regions of the southern North Sea is sparse. Between 2002 and 2004, we undertook 25 aerial line transect surveys (11,000 km on effort; altitude = 250 and 600 ft) in a 2,500 km2 coastal area off Eastern Frisia, Germany including a small portion of Dutch coastal waters. The data were g(0) corrected using a double platform approach and analysed with distance sampling software. A total of 426 harbour porpoises were sighted, including eight calves. Densities ranged between <0.1 and 1.62 individuals/km2 with peaks in February and July 2003 as well as February and May 2004. The results of our study show that harbour porpoises are present in the coastal part of the southern North Sea even during their reproductive period. However, they seem to appear in lower numbers and much more irregular than in other areas, for example off Northern Frisia. The results of this study support the recent findings that despite a decline in the mid-twentieth century, harbour porpoises are now at times quite abundant in the southern North Sea. The underlying factors of this ‘return’ should be investigated using a

  19. Southern states receive insufficient ADAP money. North Carolina, Alabama face crises.

    PubMed

    2004-08-01

    While the HIV epidemic has shifted toward poor, rural southern areas, the funding mechanism behind the AIDS Drug Assistance Program favors states with large urban areas where the epidemic first erupted decades ago, Southern AIDS advocates say. Even in states where legislatures contribute a large portion of the ADAP budget, waiting lists and eligibility restrictions continue due to a lack of adequate funding.

  20. Alkaline lavas from southern Mendoza, Argentina, extend the Patagonian DUPAL mantle field to the north

    NASA Astrophysics Data System (ADS)

    Soager, N.; Holm, P. M.; Llambias, E.

    2010-12-01

    The lavas sampled around Río Colorado ~37°S at the border of Mendoza and Neuquén provinces, Argentina, define an OIB-like end-member composition for the Pleistocene and Holocene activity in the Payún Matrú volcanic field. Although positioned in the far back-arc of the Andes, only a few lavas show signs of involvement of slab fluids or crustal contamination such as relatively high LILEs relative to Nb. The very low La/Nb (~0.66) and Zr/Nb (~5) and high U/Pb (0.3-0.4) of the end-member composition clearly distinguish the source from normal MORB mantle, while high Ba/Nb (~10) and K/Nb (370-400) compared to FOZO and HIMU type OIBs suggest an EM type of mantle. Overall, the trace element patterns of the Río Colorado lavas are similar to the central and north Patagonian intraplate basalts and to South Atlantic E-MORB affected by the Discovery plume and the LOMU component (le Roux et al., 2002, EPSL 203). The isotopic composition of the Río Colorado component has a 206Pb/204Pb = 18.4, 207Pb/204Pb = 15.58, 208Pb/204Pb = 38.3, 87Sr/86Sr = 0.70353 and 143Nd/144Nd = 0.51285. This composition overlaps the central and north Patagonian intraplate basalts in Pb-isotopic space but is slightly less enriched in Sr and Nd-isotopes. It is distinctly different from the FOZO like composition of the south Patagonian intraplate basalts and the nearby Juan Fernandéz plume but similar to the South Atlantic N-MORB and MORB from the southern Chile Ridge segment 4 (Sturm et al., 1999, JGR 104) described as DUPAL type. The DUPAL-MORB type isotopic composition and the plume-like trace element patterns of the Río Colorado lavas suggest the presence of a weak plume beneath the area. The eruption of the large Payún Matrú volcano and the gigantic Pleistocene flood basalts also calls for a thermal anomaly to produce these melts during a weakly compressive tectonic regime with no significant addition of slab fluids. This was supported by Burd et al. (2008, Abstr., 7th Int. Sym. And. Geo

  1. Hydrogeological and environmental impact of coal mining, Jharia coalfield, India

    NASA Astrophysics Data System (ADS)

    Choubey, Vishnu D.

    1991-05-01

    The Jharia coalfield is the most important and active minig region; it experiences groundwater inflow and affects groundwater levels in overlying aquifers, and it provides the basis for a conceptual model of the hydrogeological impacts of coal mining. The several sandstone aquifers of the overburden are separated by aquitards that limit vertical hydraulic connection, but the inflow responds to seasonal events and seems to be linked to shallow groundwater behavior. The mine drainage behavior suggests a hydraulic connection between the mine and the shallower groundwater system. The greatest declines are directly above the panels, with an immediate response to coal mining. The inflow is localized by natural and induced fracture zones and is mostly into recent workings. The groundwater behavior is controlled by hydraulic property changes caused by mine-induced fracturing. The hydrological and chemical qualities of the shallow groundwater regime in 13 mining collieries in Mukunda Block have been investigated. Water samples collected from 30 shallow monitoring dug wells were chosen for the study. Rainfall, runoff, and infiltration rates have been calculated in the area. The water-quality plottings were used to interpret the distribution of individual chemical parameters and in predicting the water quality. The underground mine water has been classified as: (1) unconfined groundwater in the calcareous siltstone and sandstone—its composition is Na, Ca, SO4 and Na-MgHCO3 with moderate total dissolved solids (TDS) 200 1480 ppm; (2) the deep groundwater originating from the coal seams and associated sediments in the near-surface environments—this is a Na-HCO3 water with higher TDS; and (3) spoil dump waters are essentially Na-HCO3 with high TDS. This article presents some hydrologic results and conclusions relating to the hydrogeological and environmental impacts of the coal mining in the Jharia coalfield.

  2. The influence of chilling requirement on the southern distribution limit of exotic Russian olive (Elaeagnus angustifolia) in western North America

    USGS Publications Warehouse

    Guilbault, Kimberly R.; Brown, C.S.; Friedman, J.M.; Shafroth, P.B.

    2012-01-01

    Russian olive (Elaeagnus angustifolia L.), a Eurasian tree now abundant along rivers in western North America, has an apparent southern distribution limit running through southern California, Arizona, New Mexico and Texas. We used field observations to precisely define this limit in relation to temperature variables. We then investigated whether lack of cold temperatures south of the limit may prevent the accumulation of sufficient chilling, inhibiting dormancy loss of seeds and buds. We found that Russian olive occurrence was more strongly associated with low winter temperatures than with high summer temperatures, and results of controlled seed germination and vegetative bud-break experiments suggest that the chilling requirements for germination and bud-break are partly responsible for the southern range limit. Both seed germination proportion and germination time decreased under conditions simulating those south of the range limit. Similarly, percentage bud break decreased when chilling dropped below values typical of the range limit. In 17–65% of the years from 1980 to 2000, the chilling accumulated at a site near the range limit (El Paso, TX) would lead to a 10% or more decrease in bud-break. The potential decline in growth could have large fitness consequences for Russian olive. If climate change exhibits a warming trend, our results suggest the chilling requirement for bud-break of Russian olive trees will not be met in some years and its southern range limit may retreat northward.

  3. Upper mantle structure beneath continents: New constraints from multi-mode Rayleigh wave data in western North America and southern Africa

    NASA Astrophysics Data System (ADS)

    Merrer, Sophie; Cara, Michel; Rivera, Luis; Ritsema, Jeroen

    2007-03-01

    We estimate the averaged 1-D shear-wave velocity of the upper mantle beneath western North America and the Kaapvaal region in southern Africa by inverting dispersion measurements of fundamental and higher Rayleigh modes recorded by ~2000 km aperture broadband arrays. The overtones at periods exceeding 25 s constrain the averaged 1-D shear-wave velocity to 650 km depth across the regional arrays. Our overtone analysis confirms the shear-wave velocity differences observed in global tomographic models with similar horizontal resolution: the western North American mantle features a prominent low velocity zone at depths 50-200 km, while the shear velocity in the upper 180-200 km of the mantle beneath southern Africa is at least 6% higher than in western North America which we interpret as the expression of a cratonic keel. There is no resolvable difference in shear-wave velocity between southern Africa and western North America below a depth of about 300 km.

  4. Influence of Large Syncline on In Situ Stress Field: A Case Study of the Kaiping Coalfield, China

    NASA Astrophysics Data System (ADS)

    Han, Jun; Zhang, Hongwei; Liang, Bin; Rong, Hai; Lan, Tianwei; Liu, Yuanzheng; Ren, Ting

    2016-11-01

    Kaiping coalfield is located in Tangshan, northern China, and the area has been mined for 130 years. The main structure is the Kaiping syncline with an axis that generally strikes north-east to east-west. Since 1998, we have measured the in situ stress using overcoring and obtained 30 sets of data in eight coal mines with depths from -260 to -1238 m. Based on the measured data, we established the trends in maximum horizontal stress, vertical stress, minimum horizontal stress, and their ratios, and the ratio of mean horizontal stress to vertical stress and depth. The relationship between magnitude and orientation of maximum horizontal stress and their relationships to the Kaiping syncline are discussed. The results show that (1) the stress field of the Kaiping coalfield is complex and non-uniform. The orientation and magnitude of principal stress from stress measurement diverge widely from the regional stress field and the stress regime, with 77 % strike-slip faulting and the remainder thrust faulting. (2) Both maximum ( σ H) and minimum ( σ h) horizontal stresses have significant differences at a similar depth; however, vertical stress σ v increases linearly with depth with a gradient of 0.025 MPa/m. The ratio ( k) of the mean horizontal stress to vertical stress is 160/ h + 1.04 < k < 300/ h + 1.14. This is higher at shallow depth and gradually decreases as depth increases. Up to 90 % of σ H/ σ h falls between 1.17 and 2.39 with an average of 1.96, and it is not closely related to depth. The σ H /σ v ranges from 1.06 to 2.43 with a bandwidth of 1 and decreases gradually with increasing depth. (3) The in situ stress field in the Kaiping coalfield is the result of the synthetic action of different levels of geological structures where both the orientation and magnitude of in situ stress are influenced by the Kaiping syncline. The σ H near the axis of the Kaiping syncline is remarkably high and decreases 8 km from the axis. The orientation of σ H near the

  5. Assessing surface sediment dynamics along the north-west coast of Marsa Dhouiba (Tunisia, southern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Khiari, Nouha; Atoui, Abdelfattah; Brahim, Mouldi; Sammari, Chérif; Charef, Abdelkrim; Aleya, Lotfi

    2016-04-01

    An investigation was conducted from summer 2012 to winter 2013 at 25 stations along the Tunisian coast near Kef Abbed at Marsa Dhouiba (north-east Mediterranean Sea) to analyse grain size, sediment mineralogy and currents. Particle-size analysis shows that sand deposits at shallow depths are characterised by S-shaped curves, indicating a degree of agitation and possible transport by rip currents near the bottom. At greater depths (between 10 and 30 m), the bottom is covered by coarse sand and gravel. A current was observed transporting sediment eastward along the coast; another seaward current was also noted. Generated by wind, swell and especially waves from west to north-west, the two currents transport clay and silt-sized sediment seaward. An Acoustic Doppler Current Profiler showed Marsa Dhouiba's coastal current to follow a direction 175° East, with its main axis running north/north-west parallel to the coast and its minor axis also running north/north-west. Analysis of current components indicates that the velocities u and v are oriented north to south. Sediment evolution in shallow waters is dependent on detrital inputs from streams and winds. The coarse fraction of surface sediments in Marsa Dhouiba presents 87% of total sediments and is located at depths of 10-30 m. Sediment dynamics in the Marsa Dhouiba region are closely related to the west/north-west swell.

  6. Foundations of Wind Turbines as Stepping Stones for Non-Indigenous Species in the Southern North Sea

    NASA Astrophysics Data System (ADS)

    De Mesel, I.; Degraer, S.; Kerckhof, F.; Schön, I.; Martens, K.

    2016-02-01

    Since 2008, offshore wind farms have been constructed in the shallow waters (<50m) of the Southern North Sea. At present, hundreds of turbines are operational and many more are planned. A new habitat for benthos has been created, with vertical hard structures in the offshore environment, extending from the sandy seabed to the sea surface. Monitoring in Belgian waters focussed on the succession of the fouling community in the sub- and intertidal zone, with special attention to non-indigenous species (NIS). A Metridium senile-Jassa herdmani dominated community developed in the subtidal, and only few NIS were present (3 out of a total of 90 species observed). Their presence was however most striking in the intertidal zone, where we identified 17 obligate intertidal species with about half of them being non-indigenous. This study confirmed the hypothesis that the introduced hard substrata within offshore wind farms play an important role in the establishment and the expansion of the population of both indigenous and non-indigenous species. Foundations of wind turbines strengthen the strategic position of NIS in the southern North Sea. An ongoing study on the population genetics of a fouling species (Patella vulgata) will, in combination with dispersal modelling, elucidate the dispersal pattern and connectivity with neighbouring areas, and the role of the foundations as stepping stones.

  7. The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields (2011 Final)

    EPA Science Inventory

    This report assesses the state of the science on the environmental impacts of mountaintop mines and valley fills (MTM-VF) on streams in the central Appalachian coalfields. These coalfields cover about 48,000 square kilometers (122 million acres) in West Virginia, Kentucky, Virgi...

  8. Fishing mortality in North Carolina's southern flounder fishery: direct estimates of instantaneous fishing mortality from a tag return experiment

    USGS Publications Warehouse

    Smith, William E.; Scharf, Frederick S.; Hightower, Joseph E.

    2009-01-01

    Estimation of harvest rates is often a critical component of fishery stock assessment and management. These assessments are often based on catch-at-age data sets generated over many years, but estimates of instantaneous fishing mortality (F) can also be obtained from a shorter-term tag return study. We conducted a 2-year tag return experiment to generate direct estimates of F for southern flounder Paralichthys lethostigma in a North Carolina estuary. The southern flounder supports lucrative commercial and recreational fisheries within the state and has experienced heavy fishing pressure for more than a decade. During 2005 and 2006, fish were captured and tagged with the assistance of commercial harvesters in the New River estuary. Tag returns were used to generate monthly estimates of F, which demonstrated a clear seasonal pattern that was consistent between years. Several important assumptions of the tag return model were accounted for through the use of double-tagged individuals, the distribution of both high- and standard-reward tags, and the completion of an independent controlled experiment to evaluate mortality related to tagging. Annual estimates of F exceeded the short-term management target in both years. Residual patterns suggest that the estimates may actually have been biased low, possibly due to delayed mixing of tagged fish. Thus, despite recently amended fishery regulations, F in the North Carolina southern flounder gill-net fishery still has the potential to greatly exceed targeted levels, which may delay stock recovery. Tag return studies can provide reliable (and nearly real-time) information about F and natural mortality as long as the experimental design addresses specific assumptions related to tagging-induced mortality, tag shedding, and nonreporting of tags.

  9. The Oligocene flora from the Uricani coalfield, Petrosani Basin, Romania

    NASA Astrophysics Data System (ADS)

    Pirnea, Roxana; Popa, Mihai E.

    2017-04-01

    The Petrosani Basin is a typical Oligocene - Miocene intramontaneous basin located in the South Carpathians. It has a SW-NE orientation and is 48-km long; its width is varying between 10 and 2 km, and it overlays the Danubian and Getic basements. The Oligocene sequences are filling the basin, with a thickness ranging between 300 and 500 m. They consist of clays, marls, bituminous shales, microconglomerates and limestones, including 22 coal beds. One essential feature of the Petrosani Basin is the occurrence of thick coal seams and the remains of a rich, 28 milion years old ecosystem. The studied material was collected from Uricani coal mine, from the „Lower Productive Horizon", Chattian in age (Upper Oligocene), and from Uricani coal waste dumps. The Lower Productive Horizon, also described as the Dalja-Uricani Formation, includes several coal seams and crops out in several areas (Buia et al., 2014). Collecting fossil plants from underground mining horizons represents a unique method for detailed understanding of coal bearing formations in a three-dimensional approach (Popa, 2011). Although the plant remains are represented by a large number of species, most specimens belong to the Family Lauraceae. The fossil flora is very well preserved, some of the leaves preserving their cuticles. The fossil plants from Uricani coal mine, Petro?ani Basin, are described, illustrated and discussed based on leaf impressions. The associated macroflora of Uricani coal mine comprises various leaf species of Daphnogene, Laurophyllum, Ocotea, Smilax and Alnus. Most of the studied woody plants are mesophytic, like Lauraceae (narrow-leaved Daphnogene, Laurophyllum), but the affinities of the plant remains from Uricani coalfield have not been clarified yet. Nonetheless, the taxonomic composition of the studied flora from Uricani coalfield points to a semi-tropical climate. The overall character of the depositional conditions of Petrosani Basin fit best to a flatland with surrounding

  10. Miners wives: Gender, culture, and society in the south Wales coalfields, 1919-1939

    SciTech Connect

    Gier, J.J.

    1993-01-01

    This study addresses the absence of historical research on the role of women in Welsh coalfield society through the use of oral history testimony, folk culture sources, literature, newspapers, union records and comparative data from other British and Australian coalfield regions. The thesis identifies the ways in which the domestic ideology and the vernacular culture of coalfield society influenced gender roles and relations in Welsh mining communities during the interwar period. Since the myth of the Miner and the Mining Mam signified the pervasive influence of both the domestic ideology and the vernacular culture, the aim of the study was to dismantle these ideals in order to reconstruct a history of miners' wives. To further this goal a life-cycle approach was used; the thesis examined courtship an marriage practices, domestic culture in the mining household, women's customary role in ritual surrounding birth and death, and their role in mining strikes and other forms of collective action. The study concludes that while the traditions of rural Wales tended to support a broader role for women in coalfield society, the domestic ideology denied the miner's wife her identity as a worker, and thus limited her participation in class struggle and obscured her role in the history of coalfield society.

  11. Evaluation of numerical models by FerryBox and Fixed Platform in-situ data in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Haller, M.; Janssen, F.; Siddorn, J.; Petersen, W.; Dick, S.

    2015-02-01

    FerryBoxes installed on ships of opportunity (SoO) provide high-frequency surface biogeochemical measurements along selected tracks on a regular basis. Within the European FerryBox Community, several FerryBoxes are operated by different institutions. Here we present a comparison of model simulations applied to the North Sea with FerryBox temperature and salinity data from a transect along the southern North Sea and a more detailed analysis at three different positions located off the English East coast, at the Oyster Ground and in the German Bight. In addition to the FerryBox data, data from a Fixed Platform of the MARNET network are applied. Two operational hydrodynamic models have been evaluated for different time periods: results of BSHcmod v4 are analysed for 2009-2012, while simulations of FOAM AMM7 NEMO have been available from MyOcean data base for 2011 and 2012. The simulation of water temperatures is satisfying; however, limitations of the models exist, especially near the coast in the southern North Sea, where both models are underestimating salinity. Statistical errors differ between the models and the measured parameters, as the root mean square error (rmse) accounts for BSHcmod v4 to 0.92 K, for AMM7 only to 0.44 K. For salinity, BSHcmod is slightly better than AMM7 (0.98 and 1.1 psu, respectively). The study results reveal weaknesses of both models, in terms of variability, absolute levels and limited spatial resolution. In coastal areas, where the simulation of the transition zone between the coasts and the open ocean is still a demanding task for operational modelling, FerryBox data, combined with other observations with differing temporal and spatial scales serve as an invaluable tool for model evaluation and optimization. The optimization of hydrodynamical models with high frequency regional datasets, like the FerryBox data, is beneficial for their subsequent integration in ecosystem modelling.

  12. Moors and Saracens in Europe: estimating the medieval North African male legacy in southern Europe

    PubMed Central

    Capelli, Cristian; Onofri, Valerio; Brisighelli, Francesca; Boschi, Ilaria; Scarnicci, Francesca; Masullo, Mara; Ferri, Gianmarco; Tofanelli, Sergio; Tagliabracci, Adriano; Gusmao, Leonor; Amorim, Antonio; Gatto, Francesco; Kirin, Mirna; Merlitti, Davide; Brion, Maria; Verea, Alejandro Blanco; Romano, Valentino; Cali, Francesco; Pascali, Vincenzo

    2009-01-01

    To investigate the male genetic legacy of the Arab rule in southern Europe during medieval times, we focused on specific Northwest African haplogroups and identified evolutionary close STR-defined haplotypes in Iberia, Sicily and the Italian peninsula. Our results point to a higher recent Northwest African contribution in Iberia and Sicily in agreement with historical data. southern Italian regions known to have experienced long-term Arab presence also show an enrichment of Northwest African types. The forensic and genomic implications of these findings are discussed. PMID:19156170

  13. Turbulent statistical characteristics associated to the north wind phenomenon in southern Brazil with application to turbulent diffusion

    NASA Astrophysics Data System (ADS)

    Arbage, Maria Cristina Andres; Degrazia, Gervásio Annes; Welter, Guilherme Sausen; Roberti, Débora Regina; Acevedo, Otávio Costa; de Moraes, Osvaldo Luiz Leal; Ferraz, Simone Teleginski; Timm, Andréa Ucker; Moreira, Virnei Silva

    2008-07-01

    A parameterization for the transport processes in a shear driven planetary boundary layer (PBL) has been established employing turbulent statistical quantities measured during the north wind phenomenon in southern Brazil. Therefore, observed one-dimensional turbulent energy spectra are compared with a spectral model based on the Kolmogorov arguments. The good agreement obtained from this comparison leads to well defined formulations for the turbulent velocity variance, local decorrelation time scale and eddy diffusivity. Furthermore, for vertical regions in which the wind shear forcing is relevant, the eddy diffusivity derived from the north wind data presents a similar profile to those obtained from the non-extensive statistical mechanics theory. Finally, a validation for the present parameterization has been accomplished, using a Lagrangian stochastic dispersion model. The Prairie Grass data set, which presents high mean wind speed, is simulated. The analysis developed in this study shows that the turbulence parameterization constructed from wind data for north wind flow cases is able to describe the diffusion in a high wind speed, shear-dominated PBL.

  14. Jurassic-Cretaceous history of Cuba: implications for the evolution of the southern margin of the North American plate

    SciTech Connect

    Barros, J.A.; Rosencrantz, E.

    1985-01-01

    The oldest Cuban sedimentary rocks, clastics of the Bajocian San Cayetano Fm. provide the earliest record of North American-Gondwana rifting as seen in Cuba. A similar clastic sequence is seen below the carbonates of the Bahamas platform. In the Pinar del Rio area, the San Cayetano is succeeded by Oxfordian limestones, the shallow water Jagua Fm. to the south and deeper water Francisco Fm. to the north. Both contain basaltic pillow lavas, related either to rifting or to leaky transform motion parallel to the margin. The Oxfordian units are overlain by Kimmeridgian to Tithonian pelagic limestones, the Guasasa and Artemisa Fms. The later interfingers with northerly derived calci-turbidites. North of the Escambray, silici-clastic fragments in late Jurassic pelagic limestones suggests that a basement high existed south of the platform until the Berriasian. The carbonate platform continues to shed debris along its southern edge throughout the Cretaceous. To the south an Aptian-Albian episode of turbidite deposition suggests that South America-Africa rifting caused tectonic disturbances in the Caribbean. Southerly derived volcanoclastics deposited during the Maastrichtian marks the start of the Cuban orogeny.

  15. Map showing structural control of breccia pipes on the southern Marble Plateau, north-central Arizona

    SciTech Connect

    Sutphin, H.B.; Wenrich, K.J.

    1988-01-01

    Solution collapse breccia pipes, concentrated throughout the southwestern corner of the Colorado Plateau in Arizona, have been mapped in detail on the southern Marble Plateau. Within the study area, 77 of the 90 (86%) collapse structures fall within northwest-trending and northeast-trending zones that cover only 23% of the total surface area.

  16. Using fire to restore pine/hardwood ecosystems in the Southern Appalachians of North Carolina

    Treesearch

    James M. Vose; Wayne T. Swank; Barton D. Clinton; Ronald L. Hendrick; Amy E. Major

    1997-01-01

    In the Southern Appalachians, mixed pine/hardwood ecosystems occupy the most xeric sites (i.e., south/west aspect ridge sites). They are typically comprised of varying proportions of pitch pine (Pinus rigida), Virginia pine (Pinus virginiana), and/or shortleaf pine (Pinus echinata) and a mixture of hardwoods, including scarlet oak (Quercus coccinea), chestnut oak (...

  17. Diameter growth models using FIA data from the Northeastern, Southern, and North Central Research Stations

    Treesearch

    Veronica C. Lessard; Ronald E. McRoberts; Margaret R. Holdaway

    2000-01-01

    Nonlinear, individual-tree, distance-independent annual diameter growth models are presented for species in two ecoregions defined by R.G. Bailey in the northern Lake States and in parts of the central and southern regions of the U.S. The models were calibrated using Forest Inventory and Analysis (FIA) data from undisturbed plots on land classified as timberland across...

  18. A meso-scale model of the central and southern North Sea: Consequences of an improved resolution

    NASA Astrophysics Data System (ADS)

    Pohlmann, Thomas

    2006-12-01

    Results of a meso-scale model with a resolution of approximately 3 km of the central and southern North Sea are presented. The effect of the meso-scale resolution is depicted by comparing these results with data obtained from a 20 km resolution model. The validation of the model by means of observed SST data and of temperature data from a hydrographic transect demonstrates that the meso-scale model is able to reproduce the observations reasonably well. A comparison of the 3 km resolution results with 20 km results additionally shows that the large-scale model is not able to reproduce all the observed features of the SST with the same accuracy, in particular in the near-coastal areas along the Dutch and German coast. The parameters, which are investigated in more detail in this study, are temperature and salinity as well as the mean and eddy kinetic energy of the residual flow. The comparison between meso-scale and large-scale results demonstrates that not only the temperature and salinity distribution but also the kinetic energy is strongly affected by the chosen grid resolution. With respect to the generated mean kinetic energy of the residual flow the refined model resolution produces an increase up to 100% in the eastern parts of the North Sea, whereas in the Humber/Wash and Southern Bight region a decrease by up to 200% was obtained. In the northern part of the North Sea the finer resolution does not lead to large changes in the mean kinetic energy because here the large-scale features of the circulation dominate which also can be resolved by the large-scale model. This also explains that the mean kinetic energy differences between small- and large-scale model results are larger in summer than in winter because in winter due to the stronger winds the large-scale circulation is more dominant than in summer. The additional eddy kinetic energy of the residual flow (defined here as the kinetic energy contained in the spatial scales between 3 and 20 km) in general

  19. Southern Cordilleran Basaltic Andesite suite, southern Chihuahua, Mexico: A link between Tertiary continental arc and flood basalt magmatism in the North America

    SciTech Connect

    Cameron, K. L.; Nimz, G. J.; Kuentz, D.; Niemeyer, S.; Gunn, S.

    1989-06-10

    Mid-Cenozoic orogenic andesites and ignimbrites of western Mexico, southwestern New Mexico, and Arizona are commonly capped by basaltic andesites, most from 29--20 Ma. We refer to these mafic lavas as the Southern Cordilleran Basaltic Andesite (SCORBA) suite, and they may constitute the most extensive Cenozoic basaltic suite in North America. The SCORBA suite has trace element and isotopic characteristics of orogenic (arc) rocks (i.g., Ba/Nb/gt/40), and silica content (53--56% SiO/sub 2/) like the Grande Ronde Basalt, which represents about 80% of the volume of the Columbia River Group. Geochemical and isotopic data are presented on SCORBA lavas and rare mafic lavas (PRE-SCORBA) interlayered with older ignimbrites from a 700-km-long NE-SW transect of southern Chihuahua, Mexico. SCORBA and PRE-SCORBA lavas with relatively low K/P (/lt/7) and differing Ba/Nd (50 versus 18) have similar isotopic compositions, arguing against their isotopic signatures being controlled by crustal assimilation. Along the entire length of the transect, the basaltic rocks have /var epsilon//sub Nd/ and /sup 87/Sr//sup 86/Sr near bulk Earth and /sup 206/Pb//sup 204/Pb and /sup 207/Pb//sup 204/Pb ratios that lie along a 1.7 Ga pseudoisochron. The Pb isotopic variation is geographically controlled, becoming more radiogenic from east to west, reflecting mixing in mantle source regions. The eastern mantle source has low/sup 206/Pb//sup 204/Pb and is a mixture of an enriched, enriched-mantle-like (EMI) component with one or more depleted components, which could include an intraplate component with relatively high Nb/Y (/gt/0.8).

  20. First field identification of the Cuonadong dome in southern Tibet: implications for EW extension of the North Himalayan gneiss dome

    NASA Astrophysics Data System (ADS)

    Fu, Jiangang; Li, Guangming; Wang, Genhou; Huang, Yong; Zhang, Linkui; Dong, Suiliang; Liang, Wei

    2017-07-01

    The Cuonadong dome exposes in east-southern margin of the North Himalayan gneiss domes (NHGD), which is reported first time in this study. The Cuonadong dome is located at the southern part of the Zhaxikang ore concentration area, which is divided into three tectono-lithostratigraphic units by two curved faults around the dome geometry from upper to lower (or from outer to inner): the upper unit, middle unit and lower unit, and the outer fault is Nading fault, while the inner fault is Jisong fault. The Cuonadong dome is a magmatic orthogneiss and leucogranite mantled by orthogneiss and metasedimentary rocks, which in turn are overlain by Jurassic metasedimentary and sedimentary rocks. The grades of metamorphism and structural deformation increase towards the core, which is correspondence with the Ridang Formation low-metamorphic schist, tourmaline granitic-biotite gneiss, garnet-mica gneiss and mylonitic quartz-mica gneiss. The Cuonadong dome preserves evidences for four major deformational events: firstly top-to-S thrust (D1), early approximately N-S extensional deformation (D2), main approximately E-W extensional deformation (D3), and late collapse structural deformation (D4) around the core of the Cuonadong dome, which are consistent to three groups lineation: approximately N-S-trending lineation including L1 and L2, E-W trending L3, and L4 with plunging towards outside of the dome, respectively. The formation of the Cuonadong dome was probably resulted from the main E-W extensional deformation which is a result of eastward flow of middle or lower crust from beneath Tibet accommodated by northward oblique underthrusting of Indian crust beneath Tibet. The establishment of the Cuonadong dome enhanced the E-W extension of the NHGD, which is further divided into two structural dome zones according to the different extensional directions: approximately N-S extensional North Himalayan gneiss domes (NS-NHGD) and E-W extensional North Himalayan gneiss domes (EW

  1. First field identification of the Cuonadong dome in southern Tibet: implications for EW extension of the North Himalayan gneiss dome

    NASA Astrophysics Data System (ADS)

    Fu, Jiangang; Li, Guangming; Wang, Genhou; Huang, Yong; Zhang, Linkui; Dong, Suiliang; Liang, Wei

    2016-07-01

    The Cuonadong dome exposes in east-southern margin of the North Himalayan gneiss domes (NHGD), which is reported first time in this study. The Cuonadong dome is located at the southern part of the Zhaxikang ore concentration area, which is divided into three tectono-lithostratigraphic units by two curved faults around the dome geometry from upper to lower (or from outer to inner): the upper unit, middle unit and lower unit, and the outer fault is Nading fault, while the inner fault is Jisong fault. The Cuonadong dome is a magmatic orthogneiss and leucogranite mantled by orthogneiss and metasedimentary rocks, which in turn are overlain by Jurassic metasedimentary and sedimentary rocks. The grades of metamorphism and structural deformation increase towards the core, which is correspondence with the Ridang Formation low-metamorphic schist, tourmaline granitic-biotite gneiss, garnet-mica gneiss and mylonitic quartz-mica gneiss. The Cuonadong dome preserves evidences for four major deformational events: firstly top-to-S thrust (D1), early approximately N-S extensional deformation (D2), main approximately E-W extensional deformation (D3), and late collapse structural deformation (D4) around the core of the Cuonadong dome, which are consistent to three groups lineation: approximately N-S-trending lineation including L1 and L2, E-W trending L3, and L4 with plunging towards outside of the dome, respectively. The formation of the Cuonadong dome was probably resulted from the main E-W extensional deformation which is a result of eastward flow of middle or lower crust from beneath Tibet accommodated by northward oblique underthrusting of Indian crust beneath Tibet. The establishment of the Cuonadong dome enhanced the E-W extension of the NHGD, which is further divided into two structural dome zones according to the different extensional directions: approximately N-S extensional North Himalayan gneiss domes (NS-NHGD) and E-W extensional North Himalayan gneiss domes (EW

  2. Utah lotus: North American legume for rangeland revegetation in southern Great Basin and Colorado Plateau

    USDA-ARS?s Scientific Manuscript database

    Utah lotus (Lotus utahensis Ottley) is a North American leguminous forb that may hold promise for rangeland revegetation in the western USA for diversifying planting mixtures, attracting pollinators, providing high quality forage, and expanding habitats for insects needed by sage grouse chicks. We ...

  3. Paleomagnetic studies of Carboniferous and Permian in the U. K. Southern North Sea: Core orientation, paleocurrent analysis, and diagenetic application

    SciTech Connect

    Turner, P. ); Hartley, A.J. )

    1991-03-01

    The U.K. southern North Sea is a major gas province with production from Carboniferous and Permian reservoirs. It was a foreland basin in Carboniferous times uplifted to form a Lower Permian desert basin and subsequently deeply buried during the Mesozoic. Paleomagnetic methods have been used for burial analysis, core orientation, and paleocurrent studies. VRM is shown to be of only limited value for core orientation; problems relating to drilling effects and deflection by ChRM will be discussed. Detailed thermal demagnetization studies are most valuable. Blocking temperature spectra can be related to burial history curves, and ChRM directions isolated and compared with Carboniferous and Permian reference directions. ChRM is a valuable parameter for core orientation and thus paleocurrent studies. Examples will be shown from the Carboniferous and Lower Permian.

  4. Microplastic contamination in brown shrimp (Crangon crangon, Linnaeus 1758) from coastal waters of the Southern North Sea and Channel area.

    PubMed

    Devriese, Lisa I; van der Meulen, Myra D; Maes, Thomas; Bekaert, Karen; Paul-Pont, Ika; Frère, Laura; Robbens, Johan; Vethaak, A Dick

    2015-09-15

    This study assessed the capability of Crangon crangon (L.), an ecologically and commercially important crustacean, of consuming plastics as an opportunistic feeder. We therefore determined the microplastic content of shrimp in shallow water habitats of the Channel area and Southern part of the North Sea. Synthetic fibers ranging from 200μm up to 1000μm size were detected in 63% of the assessed shrimp and an average value of 0.68±0.55microplastics/g w. w. (1.23±0.99microplastics/shrimp) was obtained for shrimp in the sampled area. The assessment revealed no spatial patterns in plastic ingestion, but temporal differences were reported. The microplastic uptake was significantly higher in October compared to March. The results suggest that microplastics >20μm are not able to translocate into the tissues.

  5. Seismic structure of the southern Cascadia subduction zone and accretionary prism north of the Mendocino triple junction

    USGS Publications Warehouse

    Gulick, S.P.S.; Meltzer, A.M.; Clarke, S.H.

    1998-01-01

    Four multichannel-seismic reflection profiles, collected as part of the Mendocino triple junction seismic experiment, image the toe of the southern Cascadia accretionary prism. Today, 250-600 m of sediment is subducting with the Gorda plate, and 1500-3200 m is accreting to the northern California margin. Faults imaged west and east of the deformation front show mixed structural vergence. A north-south trending, 20 km long portion of the central margin is landward vergent for the outer 6-8 km of the toe of the prism. This region of landward vergence exhibits no frontal thrust, is unusually steep and narrow, and is likely caused by a seaward-dipping backstop close to the deformation front. The lack of margin-wide preferred seaward vergence and wedge-taper analysis suggests the prism has low basal shear stress. The three southern lines image wedge-shaped fragments of oceanic crust 1.1-7.3 km in width and 250-700 m thick near the deformation front. These wedges suggest shortening and thickening of the upper oceanic crust. Discontinuities in the seafloor west of the prism provide evidence for mass wasting in the form of slump blocks and debris fans. The southernmost profile extends 75 km west of the prism imaging numerous faults that offset both the Gorda basin oceanic crust and overlying sediments. These high-angle faults, bounding basement highs, are interpreted as strike-slip faults reactivating structures originally formed at the spreading ridge. Northeast or northwest trending strike-slip faults within the basin are consistent with published focal mechanism solutions and are likely caused by north-south Gorda-Pacific plate convergence. Copyright 1998 by the American Geophysical Union.

  6. Mapping total suspended matter from geostationary satellites: a feasibility study with SEVIRI in the Southern North Sea.

    PubMed

    Neukermans, Griet; Ruddick, Kevin; Bernard, Emilien; Ramon, Didier; Nechad, Bouchra; Deschamps, Pierre-Yves

    2009-08-03

    Geostationary ocean colour sensors have not yet been launched into space, but are under consideration by a number of space agencies. This study provides a proof of concept for mapping of Total Suspended Matter (TSM) in turbid coastal waters from geostationary platforms with the existing SEVIRI (Spinning Enhanced Visible and InfraRed Imager) meteorological sensor on the METEOSAT Second Generation platform. Data are available in near real time every 15 minutes. SEVIRI lacks sufficient bands for chlorophyll remote sensing but its spectral resolution is sufficient for quantification of Total Suspended Matter (TSM) in turbid waters, using a single broad red band, combined with a suitable near infrared band. A test data set for mapping of TSM in the Southern North Sea was obtained covering 35 consecutive days from June 28 until July 31 2006. Atmospheric correction of SEVIRI images includes corrections for Rayleigh and aerosol scattering, absorption by atmospheric gases and atmospheric transmittances. The aerosol correction uses assumptions on the ratio of marine reflectances and aerosol reflectances in the red and near-infrared bands. A single band TSM retrieval algorithm, calibrated by non-linear regression of seaborne measurements of TSM and marine reflectance was applied. The effect of the above assumptions on the uncertainty of the marine reflectance and TSM products was analysed. Results show that (1) mapping of TSM in the Southern North Sea is feasible with SEVIRI for turbid waters, though with considerable uncertainties in clearer waters, (2) TSM maps are well correlated with TSM maps obtained from MODIS AQUA and (3) during cloud-free days, high frequency dynamics of TSM are detected.

  7. Influence of suspended particle concentration, composition and size on the variability of inherent optical properties of the Southern North Sea

    NASA Astrophysics Data System (ADS)

    Astoreca, R.; Doxaran, D.; Ruddick, K.; Rousseau, V.; Lancelot, C.

    2012-03-01

    Suspended particles play an important role in coastal waters by controlling to a large extent the variability of the water inherent optical properties (IOPs). In this study, focused on the complex waters of the Southern North Sea, the relationships between the concentration, composition and size of suspended particles and their optical properties (light absorption, and attenuation in the visible and near-infrared spectral regions) are investigated. Over a one-year period, field measurements were carried out along regular transects from the Belgian to the English coasts to cover a wide gradient of water masses. Results show that the area can be divided into three geographical zones, each one having specific biogeochemical and optical properties: Scheldt coastal zone (SCZ), Middle of the Southern North Sea (MSNS) and Thames coastal zone (TCZ). Concentrations of organic (inorganic) particles were always higher in the SCZ (TCZ). The MSNS was characterized by a high proportion of organic particles in low concentration. The spectral shape of particle attenuation reveals a wide range from negative to positive slopes. Particle size distributions reveal a power-law shape along the coasts (especially in the TCZ) and a bimodal distribution in the MSNS notably during the spring phytoplankton bloom. This bimodal size distribution and more precisely a size peak around 7 μm results in an unexpected negative spectral slope of the particle attenuation coefficient. Variations in the particulate mass-specific IOPs between the three regions were observed to predominate over seasonal variations. The implications in terms of inversion of IOPs into biogeochemical parameters, such as chlorophyll a and total suspended matter, in coastal waters are discussed.

  8. Evaluation of numerical models by FerryBox and fixed platform in situ data in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Haller, M.; Janssen, F.; Siddorn, J.; Petersen, W.; Dick, S.

    2015-11-01

    For understanding and forecasting of hydrodynamics in coastal regions, numerical models have served as an important tool for many years. In order to assess the model performance, we compared simulations to observational data of water temperature and salinity. Observations were available from FerryBox transects in the southern North Sea and, additionally, from a fixed platform of the MARNET network. More detailed analyses have been made at three different stations, located off the English eastern coast, at the Oyster Ground and in the German Bight. FerryBoxes installed on ships of opportunity (SoO) provide high-frequency surface measurements along selected tracks on a regular basis. The results of two operational hydrodynamic models have been evaluated for two different time periods: BSHcmod v4 (January 2009 to April 2012) and FOAM AMM7 NEMO (April 2011 to April 2012). While they adequately simulate temperature, both models underestimate salinity, especially near the coast in the southern North Sea. Statistical errors differ between the two models and between the measured parameters. The root mean square error (RMSE) of water temperatures amounts to 0.72 °C (BSHcmod v4) and 0.44 °C (AMM7), while for salinity the performance of BSHcmod is slightly better (0.68 compared to 1.1). The study results reveal weaknesses in both models, in terms of variability, absolute levels and limited spatial resolution. Simulation of the transition zone between the coasts and the open sea is still a demanding task for operational modelling. Thus, FerryBox data, combined with other observations with differing temporal and spatial scales, can serve as an invaluable tool not only for model evaluation, but also for model optimization by assimilation of such high-frequency observations.

  9. Velocity-depth model estimation for a subsalt target from the Southern Gas Basin of the North Sea

    SciTech Connect

    Yilmaz, O.; Rutledge, J.; Sandvin, O.; Godfrey, B. )

    1996-01-01

    The Southern Gas Basin of the North Sea has been subjected to extensional tectonics, primarily in the east-west direction. Subsequent occurrence of the salt diapirism gave rise to the presence of complex structures. By doing a depth-domain analysis of a 3-D seismic survey data from an area in the Southern Gas Basin, we delineated the structural geometry of the top Rotliegendes formation beneath the complex Zechstein diapiric formation. This required an accurate estimate of the velocity-depth model above the Zechstein diapiric formation and removal of its deleterious effect on the underlying Permian sands of Rotliegendes and deeper targets. We conducted a layer-by-layer depth-domain analysis, and used coherency inversion to estimate layer velocities and 3-D poststack depth migration to delineate reflector geometries down to top Zechstein. We verified the accuracy of the velocity-depth model for the overburden above Zechstein by analyzing image gathers from prestack depth migration. We then analyzed constant-half-space image-gather stacks to estimate velocities for the substratum including Zechstein and the underlying Carboniferous sequence. Finally, we performed 3-D prestack depth migration to delineate the base Zechstein - top Rotliegendes geometry. This study demonstrates the need for depth-domain analysis of seismic data to derive accurate structure maps for targets beneath complex structures associated with salt and overthrust tectonics. The final output from depth-domain analysis -- a velocity-depth model, can then be used as a canvas for a reservoir model.

  10. Velocity-depth model estimation for a subsalt target from the Southern Gas Basin of the North Sea

    SciTech Connect

    Yilmaz, O.; Rutledge, J.; Sandvin, O.; Godfrey, B.

    1996-12-31

    The Southern Gas Basin of the North Sea has been subjected to extensional tectonics, primarily in the east-west direction. Subsequent occurrence of the salt diapirism gave rise to the presence of complex structures. By doing a depth-domain analysis of a 3-D seismic survey data from an area in the Southern Gas Basin, we delineated the structural geometry of the top Rotliegendes formation beneath the complex Zechstein diapiric formation. This required an accurate estimate of the velocity-depth model above the Zechstein diapiric formation and removal of its deleterious effect on the underlying Permian sands of Rotliegendes and deeper targets. We conducted a layer-by-layer depth-domain analysis, and used coherency inversion to estimate layer velocities and 3-D poststack depth migration to delineate reflector geometries down to top Zechstein. We verified the accuracy of the velocity-depth model for the overburden above Zechstein by analyzing image gathers from prestack depth migration. We then analyzed constant-half-space image-gather stacks to estimate velocities for the substratum including Zechstein and the underlying Carboniferous sequence. Finally, we performed 3-D prestack depth migration to delineate the base Zechstein - top Rotliegendes geometry. This study demonstrates the need for depth-domain analysis of seismic data to derive accurate structure maps for targets beneath complex structures associated with salt and overthrust tectonics. The final output from depth-domain analysis -- a velocity-depth model, can then be used as a canvas for a reservoir model.

  11. Teleconnection between the North Indian Ocean high swell events and meteorological conditions over the Southern Indian Ocean

    NASA Astrophysics Data System (ADS)

    Remya, P. G.; Vishnu, S.; Praveen Kumar, B.; Balakrishnan Nair, T. M.; Rohith, B.

    2016-10-01

    The link between North Indian Ocean (NIO) high swell events and the meteorological conditions over the Southern Indian Ocean (SIO) is explored in this article, using a combination of in situ measurements and model simulations for the year 2005. High waves, without any sign in the local winds, sometimes cause severe flooding events along the south-west coast of India, locally known as the Kallakkadal events and cause major societal problems along the coasts. In situ observations report 10 high swell events in NIO during 2005. Our study confirms that these events are caused by the swells propagating from south of 30°S. In all cases, 3-5 days prior to the high swell events in NIO, we observed a severe low pressure system, called the Cut-Off Low (COL) in the Southern Ocean. These COLs are quasistationary in nature, providing strong (˜25 ms-1) and long duration (˜3 days) surface winds over a large fetch; essential conditions for the generation of long-period swells. The intense equator ward winds associated with COLs in the SIO trigger the generation of high waves, which propagate to NIO as swells. Furthermore, these swells cause high wave activity and sometimes Kallakkadal events along the NIO coastal regions, depending on the local topography, angle of incidence, and tidal conditions. Our study shows that such natural hazards along the NIO coasts can be forecasted at least 2 days in advance if the meteorological conditions of the SIO are properly monitored.

  12. Air temperature change in the northern and southern tropical Andes linked to North-Atlantic stadials and Greenland interstadials

    NASA Astrophysics Data System (ADS)

    Urrego, Dunia H.; Hooghiemstra, Henry

    2016-04-01

    We use eight pollen records reflecting climatic and environmental change from northern and southern sites in the tropical Andes. Our analysis focuses on the signature of millennial-scale climate variability during the last 30,000 years, in particular the Younger Dryas (YD), Heinrich stadials (HS) and Greenland interstadials (GI). We identify rapid responses of the vegetation to millennial-scale climate variability in the tropical Andes. The signature of HS and the YD are generally recorded as downslope migrations of the upper forest line (UFL), and are likely linked to air temperature cooling. The GI1 signal is overall comparable between northern and southern records and indicates upslope UFL migrations and warming in the tropical Andes. Our marker for lake level changes indicates a north to south difference that could be related to moisture availability. The direction of air temperature change recorded by the Andean vegetation is consistent with millennial-scale cryosphere and sea surface temperature records from the American tropics, but suggests a potential difference between the magnitude of temperature change in the ocean and the atmosphere.

  13. Flows of Antarctic bottom water through fractures in the southern part of the North Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Morozov, E. G.; Tarakanov, R. Yu.; Makarenko, N. I.

    2015-11-01

    We study the flows of bottom waters of the Antarctic origin in deep fracture zones of the southern part of the North Mid-Atlantic Ridge. In the autumn of 2014, an expedition onboard the RV Akademik Sergey Vavilov carried out measurements of current velocities and thermohaline properties of bottom water in several quasi-zonal fractures in the southern part of the Northern Mid-Atlantic Ridge, which connect the deep basins of the West and East Atlantic, the Vema Fracture Zone (FZ) (10°50' N) and a group of sub-equatorial fractures: Doldrums (8°15' N), Vernadsky (7°40' N), and a nameless fracture at 7°30' N. The estimates of bottom water (θ < 2.0°C) transport through this group based on measurements from 2014 are approximately 0.28 Sv (1 Sv = 106 m3/s), which is close to 25% of the transport estimate through the Vema FZ (1.20 Sv) obtained in the same expedition. The coldest bottom water temperatures among the investigated fractures were recorded in the Vema FZ.

  14. Effects of watershed land use and geomorphology on stream low flows during severe drought conditions in the southern Blue Ridge Mountains, Georgia and North Carolina, United States

    Treesearch

    Katie Price; C. Jackson; Albert Parker; Trond Reitan; John Dowd; Mike Cyterski

    2011-01-01

    Land use and physiographic variability influence stream low flows, yet their interactions and relative influence remain unresolved. Our objective was to assess the influence of land use and watershed geomorphic characteristics on low-flow variability in the southern Blue Ridge Mountains of North Carolina and Georgia. Ten minute interval discharge data for 35 streams (...

  15. Institutional Research in Emerging Countries of Southern Africa, Latin America, and the Middle East and North Africa: Global Frameworks and Local Practices

    ERIC Educational Resources Information Center

    Lange, Lis; Saavedra, F. Mauricio; Romano, Jeanine

    2013-01-01

    This chapter presents a synthesis of the conceptualization and practice of institutional research (IR) in higher education (HE) in emerging countries across Southern Africa, Latin America and the Middle East and North Africa (MENA) regions. The chapter contextualizes the growing need for IR in these regions, identifies problems and challenges…

  16. IPM of the southern green stink bug, Nezara viridula (Hemiptera: Pentatomidae) using trap and refuge crops within tomato fields in North Florida

    USDA-ARS?s Scientific Manuscript database

    The Southern Green Stink Bug (SGSB), Nezara viridula (Hemiptera: Pentatomidae) is a serious insect pest of tomatoes and numerous vegetable and fruit plants in north Florida. We evaluated three trap crops and three refuge crops to investigate their potential to be used for IPM (Integrated Pest Manag...

  17. Institutional Research in Emerging Countries of Southern Africa, Latin America, and the Middle East and North Africa: Global Frameworks and Local Practices

    ERIC Educational Resources Information Center

    Lange, Lis; Saavedra, F. Mauricio; Romano, Jeanine

    2013-01-01

    This chapter presents a synthesis of the conceptualization and practice of institutional research (IR) in higher education (HE) in emerging countries across Southern Africa, Latin America and the Middle East and North Africa (MENA) regions. The chapter contextualizes the growing need for IR in these regions, identifies problems and challenges…

  18. The Practice of Institutional Research. Proceedings of a Joint Conference of the Southern Association for Institutional Research and the North Carolina Association for Institutional Research (Charlotte, North Carolina, October 29-30, 1981).

    ERIC Educational Resources Information Center

    Martin, Mary P., Ed.; Staman, E. Michael, Ed.

    Proceedings of a 1981 joint conference sponsored by the Southern Association for Institutional Research (SAIR) and the North Carolina Association for Institutional Research are presented. The conference theme was the practice of institutional research. Contents include preconference workshop reports, speeches, abstracts of papers, and reports of…

  19. The Practice of Institutional Research. Proceedings of a Joint Conference of the Southern Association for Institutional Research and the North Carolina Association for Institutional Research (Charlotte, North Carolina, October 29-30, 1981).

    ERIC Educational Resources Information Center

    Martin, Mary P., Ed.; Staman, E. Michael, Ed.

    Proceedings of a 1981 joint conference sponsored by the Southern Association for Institutional Research (SAIR) and the North Carolina Association for Institutional Research are presented. The conference theme was the practice of institutional research. Contents include preconference workshop reports, speeches, abstracts of papers, and reports of…

  20. Kinematic analysis of a possible suture in the southern Appalachians, northwestern North Carolina

    SciTech Connect

    Mallard, L.D.; Adams, M.G.; Stewart, K.G. . Dept. of Geology)

    1994-03-01

    The contact between Grenville-age basement and the Ashe Metamorphic Suite juxtaposes rocks of the Laurentian continent with rocks of apparent oceanic affinities. The occurrence of ultramafic rocks and recently discovered eclogite along the base of the Ashe Metamorphic Suite suggests the possibility that this contact is a suture. Previous workers have demonstrated that the basement/Ashe Metamorphic suite contact is a northwest-directed thrust fault north of the Grandfather Mountain window. Recent maps published by the North Carolina Geological survey show the contact as a folded thrust fault south of the Grandfather Mountain window. The authors detailed kinematic analyses show that the basement/Ashe Metamorphic Suite contact is not a folded thrust surface; instead, they have identified two distinct northeast-striking fault contacts, one showing strike-slip and the other showing dip-slip motion. Kinematic indicators (asymmetric porphyroclasts, shear bands, mica fish, and S-C fabrics) from mylonites along a portion of the basement/Ashe Metamorphic suite contact from Bakersville to Barnardsville, NC demonstrate dextral strike-slip movement on the eastern fault. Preliminary structural analyses of mylonites on the western fault indicate top-to-the-southeast dip-slip movement. The minerals in these mylonites are partially to totally annealed unlike mylonites from the greenschist facies shear zones along the basement/Ashe Metamorphic Suite contact north of the Grandfather Mountain window.

  1. Abrupt changes in the southern extent of North Atlantic Deep Water during Dansgaard-Oeschger events

    NASA Astrophysics Data System (ADS)

    Gottschalk, Julia; Skinner, Luke C.; Misra, Sambuddha; Waelbroeck, Claire; Menviel, Laurie; Timmermann, Axel

    2015-12-01

    The glacial climate system transitioned rapidly between cold (stadial) and warm (interstadial) conditions in the Northern Hemisphere. This variability, referred to as Dansgaard-Oeschger variability, is widely believed to arise from perturbations of the Atlantic Meridional Overturning Circulation. Evidence for such changes during the longer Heinrich stadials has been identified, but direct evidence for overturning circulation changes during Dansgaard-Oeschger events has proven elusive. Here we reconstruct bottom water [CO32-] variability from B/Ca ratios of benthic foraminifera and indicators of sedimentary dissolution, and use these reconstructions to infer the flow of northern-sourced deep water to the deep central sub-Antarctic Atlantic Ocean. We find that nearly every Dansgaard-Oeschger interstadial is accompanied by a rapid incursion of North Atlantic Deep Water into the deep South Atlantic. Based on these results and transient climate model simulations, we conclude that North Atlantic stadial-interstadial climate variability was associated with significant Atlantic overturning circulation changes that were rapidly transmitted across the Atlantic. However, by demonstrating the persistent role of Atlantic overturning circulation changes in past abrupt climate variability, our reconstructions of carbonate chemistry further indicate that the carbon cycle response to abrupt climate change was not a simple function of North Atlantic overturning.

  2. Sedimentary sulfides in dune sands of Spiekeroog Island, southern North Sea: A biogeochemical study of sulfur isotope partitioning

    NASA Astrophysics Data System (ADS)

    Seibert, Stephan; Schubert, Florian; Schmiedinger, Iris; Böttcher, Michael E.; Massmann, Gudrun

    2017-04-01

    The formation of iron sulfides in sandy sediments and the associated development of stable isotope signatures is still mechanistically not understood. In dune sands under impact of both fresh and saline water several physico-chemical gradients may develop leading to distinctly different biogeochemical zones. In the present study, a 10 m long core from a dune base at the North Eastern part of Spiekeroog Island, southern North Sea, was investigated for the elemental and stable isotope composition. The pyrite (TRIS) content was quantitatively extracted via an acidic Cr(II) distillation procedure and the stable sulfur isotope composition was determined by means of C-irmMS. The pore waters display a downcore increase in salt contents and a mixing between fresh and salt water. The accumulation of metabolites at depth indicate an increasing superimposition of mixing by microbial decomposition of dissolved organic matter with only limited net sulfate reduction. This indicates an essential open system with respect to dissolved sulfate. The sands were found to be very low in TOC, TIC, and TRIS and dominated by quartz minerals. Under the assumption that North Sea water sulfate was the only substantial sulfate source (d34S = + 21per mil), the sedimentary sulfides indicate an overall sulfur isotope discrimination upon microbial sulfate reduction between 39 and 52 per mil, which is within the range of results from other fully marine sands from the Spiekeroog area and laboratory studies with pure cultures of sulfate-reducing bacteria under low cellular sulfate reduction rates. Further investigations are on the way to understand the processes leading to the iron sulfide formation in these organic-poor substrates.

  3. Aminostratigraphy of Middle and Late Pleistocene deposits in The Netherlands and the southern part of the North Sea Basin

    NASA Astrophysics Data System (ADS)

    Meijer, T.; Cleveringa, P.

    2009-09-01

    A review of all available amino acid racemization D (alloisoleucine)/L (isoleucine) data from the whole shell of four molluscan species from Late and late Middle Pleistocene deposits of the Netherlands is presented. The data allow the distinction of 5 aminostratigraphical units, NAZ (Netherlands Amino Zone) A-E, each representing a temperate stage. The zones are correlated with marine isotope stages 1, 5e, 7, 9, and 11 respectively. Apart from NAZ-D (MIS 9), in all aminozones the marine transgression reached the present-day onshore area of the Netherlands. The transgression during NAZ-C (Oostermeer Interglacial: MIS 7) seems to be at least as widespread as its counterpart during NAZ-B (Eemian: MIS 5e) in the southern bight of the North Sea Basin. The stratigraphic position of the Oostermeer Interglacial is just below deposits of the Drente phase of the Saalian and because of this position the interglacial marine deposits have formerly erroneously considered to be of Holsteinian age. Neede, the 'classic' Dutch Holsteinian site, is dated in NAZ-E (MIS 11), like Noordbergum. Although the validity of these zones has been checked with independent data, some overlap between succeeding zones may occur. The relation between amino acid data from elsewhere in the North Sea Basin and the Netherlands amino zonation is discussed. The deposits at the Holsteinian stratotype Hummelsbüttel in North West Germany are dated in NAZ-D. This interglacial correlates with MIS 9. The Belvédère Interglacial, which is of importance for its archaeology, is in NAZ-D (MIS 9) and therefore of Holsteinian age as well. The lacustroglacial 'pottery clays' in the Noordbergum area are deposits from two glacial stages, which can be correlated with MIS 8 and 10 (the Elsterian). The pottery clay that is considered equivalent to the German 'Lauenburger Ton' correlates with MIS 10.

  4. Investigating crustal deformation associated with the North America-Pacific plate boundary in southern California with GPS geodesy

    NASA Astrophysics Data System (ADS)

    Spinler, Joshua C.

    The three largest earthquakes in the last 25 years in southern California occurred on faults located adjacent to the southern San Andreas fault, with the M7.3 1992 Landers and M7.1 1999 Hector Mine earthquakes occurring in the eastern California shear zone (ECSZ) in the Mojave Desert, and the M7.2 2010 El Mayor-Cucapah earthquake occurring along the Laguna Salada fault in northern Baja California, Mexico. The locations of these events near to but not along the southern San Andreas fault (SSAF) is unusual in that the last major event on the SSAF occurred more than 300 years ago, with an estimated recurrence interval of 215 +/- 25 years. The focus of this dissertation is to address the present-day deformation field along the North America-Pacific plate boundary in southern California and northern Baja California, through the analysis of GPS data, and elastic block and viscoelastic earthquake models to determine fault slip rates and rheological properties of the lithosphere in the plate boundary zone. We accomplish this in three separate studies. The first study looks at how strain is partitioned northwards along-strike from the southern San Andreas fault near the Salton Sea. We find that estimates for slip-rates on the southern San Andreas decrease from ~23 mm/yr in the south to ~8 mm/yr as the fault passes through San Gorgonio Pass to the northwest, while ~13-18 mm/yr of slip is partitioned onto NW-SE trending faults of the ECSZ where the Landers and Hector Mine earthquakes occurred. This speaks directly to San Andreas earthquake hazards, as a reduction in the slip rate would require greater time between events to build up enough slip deficit in order to generate a large magnitude earthquake. The second study focuses on inferring the rheological structure beneath the Salton Trough region. This is accomplished through analysis of postseismic deformation observed using a set of the GPS data collected before and after the 2010 El Mayor-Cucapah earthquake. By

  5. Interpretation of fluorometric chlorophyll registrations with Algal pigment analysis along a ferry transect in the Southern North Sea

    NASA Astrophysics Data System (ADS)

    Althuis, Ij. A.; Gieskes, W. W. C.; Villerius, L.; Colijn, F.

    In 1991 chlorophyll a was measured continously by fluorometry on the ferry 'Norstar', between Zeebrugge and Hull. In order to assess the usefulness of this platform for monitoring of long-term changes in phytoplankton distribution in the southern North Sea, calibration cruises were carried out in January, April, June and August with RV 'Holland' to relate algal pigment fingerprints to the fluorescence record. Chlorophyll a concentrations, determined after HPLC separation, allowed a quantification of the continuous fluorescence signal. The relation between fluorescence and chlorophyll a content was found to be rather constant in June and August and allowed a prediction of the chlorophyll a concentration from fluorescence measurements within 21%. In Janaury and April, however, this relation was different for separate hydrographic regions. In April, a major chlorophyll derivative, an allomer indicative of degradation of algal matter, was abundant near the Belgian coast. During the decay of the Phaeocystis bloom, this high concentration of allomerized chlorophyll a increased the 'background' fluorescence signal. In January, enhancement of fluorescence caused by light scattering of non-algal suspended matter could be observed most clearly near the English coast, where the algal concentration was low (0.5 μg·dm -3) while suspended (inorganic) matter concentration was high (30 mg·dm -3). By applying linear relations, calculated for every hydrographic region, prediction of the chlorophyll a concentration could be improved to an accuracy of 38%. An analysis of taxon-specific chlorophylls and carotenoids reveals that the distribution of individual pigments and of pigment ratios was indicative of taxonomic composition of the phytoplankton. Patterns in pigment concentrations along the section suggest the same phytoplankton abundance gradients and patchiness as revealed by the continuous fluorescence measurement. A succession in the phytoplankton population was apparent

  6. Changing sedimentation in tidal flat sediments of the southern North Sea from the Holocene to the present: a geochemical approach

    NASA Astrophysics Data System (ADS)

    Dellwig, O.; Hinrichs, J.; Hild, A.; Brumsack, H.-J.

    2000-12-01

    This study presents geochemical evidence for a change in depositional energy conditions of tidal flat sediments (southern North Sea) from the Holocene, i.e. human unaffected, to present-day conditions. We investigated Holocene and present tidal flat sediments and suspended particulate matter (SPM) from the NW German coastal area (Spiekeroog Island back-barrier area and Jade Bay), as well as sediments from the Helgoland Island mud hole area. Samples were analysed for bulk parameters (TC, TIC), major (Al, Ca, Fe, Mg, K, P, Si, Ti), and trace elements (Ba, Pb, Rb, Sr, V, Zn, Zr). Enrichment factors versus average shale reveal four groups of elements for the investigated Holocene and present sediments. Fe, Mg, K, Ba, Rb, and V show a shale-like behaviour and enrichments of Ca and Sr reflect the occurrence of carbonate, whereas higher levels of P, Pb, and Zn in the present samples are due to pollution. The fourth group consists of Si, Ti, and Zr, which may be used as indicators of depositional energy because these elements are concentrated by particle sorting effects. The most pronounced geochemical difference between the Holocene and present tidal flat sediments is an enrichment of Zr in the present samples. As Zr is commonly associated with heavy minerals, this enrichment indicates a higher depositional energy environment in the present sediments, which can be traced to modern dike building. The same effect, i.e. increasing current velocities, is responsible for a general depletion of fine-grained, Al-rich, material in the present sediments. The examination of SPM shows that large amounts of this fine-grained material are present in the water column and may be transported from the intertidal system into the open North Sea. The comparison of a calculated Holocene clay accumulation rate with modern estimates of SPM deposition in the German Bight reveals about a two-fold higher deposition of fine material in the Holocene tidal flats. As the sediments from the Helgoland

  7. How can hyper-extension be integrated into kinematic plate reconstructions? The example of the southern North Atlantic

    NASA Astrophysics Data System (ADS)

    Nirrengarten, Michael; Manatschal, Gianreto; Tugend, Julie; Kusznir, Nick; Sauter, Daniel

    2017-04-01

    Plate kinematic models aim to perform palinspastic fits of continental blocks and to restore their motion through time using isochronal features such as oceanic magnetic anomalies. In the absence of oceanic magnetic anomalies, restorations suppose a continuous motion between a full fit position (tidiest/maximal fit) and the position determined by the first oceanic magnetic anomaly. However, recent studies show that the domains between undeformed continental crust and unequivocal oceanic crust can be several hundreds of kilometers wide at magma-poor margins, formed by so called hyper-extended rift domains. The kinematics, rates and processes forming these rift domains are as yet not well understood leading to problematic integration into plate kinematic reconstructions. In this study, we propose a new restoration methodology that integrates the spatio-temporal evolution of hyper-extended domains into kinematic plate modeling. To do so, we use the example of the well constrained southern North Atlantic magma-poor rifted margins. The extensive dataset, including deep ODP drill holes and high quality public available seismic data, enables good spatio-temporal calibrations. This new approach is based on the mapping of different rift domains, including un-deformed continental crust, thinned crust, exhumed mantle and oceanic crust. In order to account for the continental crust extension and to define the limit of the reconstruct continental crust, the volume of deformed continental crust is restored back to its initial thickness, enabling pre-deformation continental polygons and a pre-rift continental fit to be defined. Crustal thickness maps are determined by 3D gravity inversion which includes lithosphere thermal gravity anomaly correction and magmatic additions. Time constraints, if available, may be obtained from the dating of the necking age, mantle exhumation and lithospheric breakup using geochronological or stratigraphical methods. We use the plate reconstruction

  8. Modelling the seasonal occurrence and distribution of humanpathogenic bacteria within the German Bight, southern North Sea

    NASA Astrophysics Data System (ADS)

    Schakau, Vanessa; Lettmann, Karsten A.; Wolff, Jörg-Olaf

    2015-04-01

    In recent years, the occurrence of human-pathogenic bacteria of the genus Vibrio in the North Sea and the Baltic Sea has come into the focus of many marine research activities, as different Vibrio strains caused harmful infections, especially in summers 2003, 2006, 2010 and 2014. Furthermore, it is anticipated that under global warming conditions, the risk of the occurrence of human-pathogenic in summer season will increase very likely. To present knowledge temperature and salinity are the most powerful predictors of the occurrence of Vibrio spp. in coastal waters. However, studies support the interaction of human-pathogenic Vibrio spp. with different host and vector organisms like chitinous zooplankton or with predator organisms such as Vibrio-specific bacteriophages. A modeling system has been developed to understand and predict the occurrence and distribution of harmful Vibrio spp. within the North Sea with a special focus on the German Bight including the shallower Wadden Sea areas and the estuaries of Ems, Weser and Elbe. On the one hand, this modeling system is based on the unstructured-mesh hydrodynamic model FVCOM, which can predict the oceanic circulation and distributions of temperature and salinity within the German Bight for appropriate present and future climate conditions. On the other hand, a biological module has been attached, which can simulate the distribution and abundances of Vibrio spp.. In detail, apart from specific Vibrio strains, this biological module incorporates functional groups of phyto- and zooplankton and bacteriophages as potential host- and predator-organisms. In a first study, this modeling system has been applied to a hot summer season in 2006. It has been demonstrated that this system can reproduce the valid hydrodynamic conditions within the North Sea region of interest including temperature and salinity distribution patterns. In addition, reasonable temporal and spatial patterns of Vibrio abundances have been obtained.

  9. Towards an integrated view of benthic and pelagic processes in the southern North Sea (German Bight)

    NASA Astrophysics Data System (ADS)

    Friedrich, Jana; van Beusekom, Justus; Neumann, Andreas; Naderipour, Celine

    2015-04-01

    The North Sea can be classified as a semi-enclosed shelf on the western-European continent. Atlantic influences are mainly through the Fair Isle current Channel in the North, and through the Strait of Dover in the South. An anti-clockwise circulation prevails, driven by mainly semi-diurnal tides and winds. The German Bight is located in the south-eastern part of the North Sea, and is strongly influenced by continental rivers. The outflow from the rivers Scheldt, Maas and Rhine is carried towards the German Bight with the residual currents. The German rivers Ems, Weser and Elbe directly debouche into the German Bight. On the shallow shelf, the water column is completely mixed by tidal forces and wind, largely preventing downward flux of particles and instead fostering temporary deposition and resuspension, which influences benthic mineralization. Hence, complex interactions between pelagic and benthic processes occur. Previous budget calculations indicate that the nutrient inventory has to be processed several times to support observed primary production, and, depending on water depth; only 10-20% remineralisation occurs in sediments of the German Bight whereas about 50% of organic matter is remineralised in the sediments of the shallow Wadden Sea. In this presentation, we use in-situ and ex-situ field data on pelagic and benthic oxygen respiration and benthic nutrient fluxes to assess the intense mineralization activity in the German Bight, the partitioning of benthic and pelagic processes and the factors influencing organic matter mineralization. Measurements of pelagic oxygen respiration based on Winkler titration, in-situ benthic oxygen uptake measurements based on flux-chamber landers and ex-situ incubations of intact sediment cores revealed that benthic remineralisation rates are about an order of magnitude smaller than pelagic rates, in agreement with previous budget estimates. Both benthic and pelagic oxygen respiration show a strong seasonality; with higher

  10. Unique organic remains from an upper Permian coal bearing sequence in the Talcher Coalfield, Orissa, India

    SciTech Connect

    Tripathi, A.

    2004-07-01

    The playnological assemblage of coal bearing upper Permian sequence of Talcher Coalfield registers presence of some peculiar organic remains. These are described as Orissiella gen. nov., which is characterized by a vesicle with collar-like structure at the oral end, spines and or corrugations on the body. The affinity and palaeoecological significance of Orissiella is also discussed. 12 refs., 4 figs., 2 plates.

  11. Chapter 12: Reestablishing American chestnut on mined lands in the Appalachian coalfields

    Treesearch

    Michael French; Chris Barton; Brian McCarthy; Carolyn Keiffer; Jeff Skousen; Carl Zipper; Patrick. Angel

    2017-01-01

    American chestnut was formerly a major component of forests throughout the Appalachian coalfields and beyond. Chestnut's strong, lightweight wood was naturally rot-resistant, making it a preferred timber tree for many purposes. Unlike many nut-producing trees that flower early in the year, American chestnuts flower in June and July, so they were less susceptible...

  12. Participation in Lifelong Learning: Reality or Myth? Issues Arising from a United Kingdom Coalfield Closure

    ERIC Educational Resources Information Center

    Thursfield, Denise; Henderson, Roger

    2004-01-01

    In the spring of 2004, the Selby Coalfield, the largest of the remaining coal mines in the United Kingdom (UK) will close and 2071 employees will lose their jobs. The impact of the closure will be severe in the surrounding area, and will present a challenge to local employment services and training agencies. It will also test the UK government's…

  13. Participation in Lifelong Learning: Reality or Myth? Issues Arising from a United Kingdom Coalfield Closure

    ERIC Educational Resources Information Center

    Thursfield, Denise; Henderson, Roger

    2004-01-01

    In the spring of 2004, the Selby Coalfield, the largest of the remaining coal mines in the United Kingdom (UK) will close and 2071 employees will lose their jobs. The impact of the closure will be severe in the surrounding area, and will present a challenge to local employment services and training agencies. It will also test the UK government's…

  14. Sedimentary response to tectonism in the extensional Chihuahua trough, Cretaceous of Southern North America

    NASA Astrophysics Data System (ADS)

    Budhathoki, P.; Langford, R. P.; Pavlis, T. L.

    2009-12-01

    During the Jurassic and Cretaceous, the Chihuahua Trough formed an extensional basin, extending from the Gulf of Mexico to Southern Arizona, along the Present Border of the United States and Mexico. West of the Big Bend of Texas, Jurassic and Cretaceous sediments are less than 150 m thick, and in many areas are absent. The sedimentary package thickens to over 3km within the trough. The Albian Cox Sandstone is one of the most areally extensive formations and consists of interbedded fluvial coastal and shallow marine sandstones and shales. In this study area, shales (10-70 m) are thicker more than sandstone beds (2-10 m). This unit is overlain by Finlay formation, a fine crystalline gray limestone and underlain by Bluff Mesa formation, a fossiliferous shallow marine limestone. Cross-bedded, brown, fine to medium grained sandstone, interbedded with siltstone, shale and limestone are characteristic lithology of the Cox. The Indio Mountains of Trans-Pecos Texas offer an ideal location to study how this package accommodates the deformation associated with the subsiding Chihuahua trough. A continuous outcrop extends over 30 km oblique to the basin margin and thickens from approximately 375 m on the northern side to 437 m on the southern side of the 10 km section studied so far. One important mechanism is rotation of the strata into the basin, followed by truncation along sequence boundaries. The lower two sequence in the southern Indio mountains are rotated down to the basin relative to Finlay. The lowest sequences thicken from an erosional pinch out towards the South. Shale beds thicken within the rotated strata and accommodate some of the tilting. For example, Thickness of the shale bed varies from 18 m to 70 m within a 2 km distance. However, erosional truncation of the tilted strata accounts for most of the increases in thickness within sequences. The base of the formation has been rotated about 6 degrees south relative to the top of the formation. Another observed

  15. Conservation status of North American freshwater crayfish (Decapoda: Cambaridae) from the southern United States

    USGS Publications Warehouse

    Loughman, Zachary J.; Welsh, Stuart; Fetzner, James W.; Thoma, Roger F.

    2015-01-01

    A list is provided of all crayfishes (family Cambaridae) in the southern United States, which includes common names, global conservation status, an alternative review of the conservation status based on the IUCN red list criteria, and state distribution. This list includes 357 native crayfishes, of which 12 (3.4%) are critically endangered, 37 (10.4%) are endangered, 126 (35.3%) are vulnerable, 181 (50.7%) are lower risk, and 1 (0.3%) is not evaluated. The leading factors causing imperilment are restricted ranges caused by anthropogenic impacts from changes in land use, contaminants, invasion by non-indigenous species, and habitat fragmentation. In order to conserve and manage diversity of native crayfish, consistency is needed in determining conservation status and more complete distribution and life history information are needed for about 60% of species.

  16. Assessment of Coal Geology, Resources, and Reserves in the Gillette Coalfield, Powder River Basin, Wyoming

    USGS Publications Warehouse

    Luppens, James A.; Scott, David C.; Haacke, Jon E.; Osmonson, Lee M.; Rohrbacher, Timothy J.; Ellis, Margaret S.

    2008-01-01

    The Gillette coalfield, within the Powder River Basin in east-central Wyoming, is the most prolific coalfield in the United States. In 2006, production from the coalfield totaled over 431 million short tons of coal, which represented over 37 percent of the Nation's total yearly production. The Anderson and Canyon coal beds in the Gillette coalfield contain some of the largest deposits of low-sulfur subbituminous coal in the world. By utilizing the abundance of new data from recent coalbed methane development in the Powder River Basin, this study represents the most comprehensive evaluation of coal resources and reserves in the Gillette coalfield to date. Eleven coal beds were evaluated to determine the in-place coal resources. Six of the eleven coal beds were evaluated for reserve potential given current technology, economic factors, and restrictions to mining. These restrictions included the presence of railroads, a Federal interstate highway, cities, a gas plant, and alluvial valley floors. Other restrictions, such as thickness of overburden, thickness of coal beds, and areas of burned coal were also considered. The total original coal resource in the Gillette coalfield for all eleven coal beds assessed, and no restrictions applied, was calculated to be 201 billion short tons. Available coal resources, which are part of the original coal resource that is accessible for potential mine development after subtracting all restrictions, are about 164 billion short tons (81 percent of the original coal resource). Recoverable coal, which is the portion of available coal remaining after subtracting mining and processing losses, was determined for a stripping ratio of 10:1 or less. After mining and processing losses were subtracted, a total of 77 billion short tons of coal were calculated (48 percent of the original coal resource). Coal reserves are the portion of the recoverable coal that can be mined, processed, and marketed at a profit at the time of the economic

  17. Post-Clovis survival of American Mastodon in the southern Great Lakes Region of North America

    USGS Publications Warehouse

    Woodman, N.; Beavan, Athfield N.

    2009-01-01

    The end of the Pleistocene in North America was marked by a wave of extinctions of large mammals, with the last known appearances of many species falling between ca. 11,000-10,000??14C yr BP. Temporally, this period overlaps with the Clovis Paleoindian cultural complex (11,190-10,530??14C yr BP) and with sudden climatic changes that define the beginning of the Younger Dryas chronozone (ca. 11,000-10,000??14C yr BP), both of which have been considered as potential proximal causes of this extinction event. Radiocarbon dating of enamel and filtered bone collagen from an extinct American Mastodon (Mammut americanum) from northern Indiana, USA, by accelerator mass spectrometer yielded direct dates of 10,055 ?? 40??14C yr BP and 10,032 ?? 40??14C yr BP, indicating that the animal survived beyond the Clovis time period and into the late Younger Dryas. Although the late survival of this species in mid-continental North America does not remove either humans or climatic change as contributing causes for the late Pleistocene extinctions, neither Clovis hunters nor the climatic perturbations initiating the Younger Dryas chronozone were immediately responsible for driving mastodons to extinction. ?? 2009 University of Washington.

  18. Post-Clovis survival of American Mastodon in the southern Great Lakes Region of North America

    NASA Astrophysics Data System (ADS)

    Woodman, Neal; Beavan Athfield, Nancy

    2009-11-01

    The end of the Pleistocene in North America was marked by a wave of extinctions of large mammals, with the last known appearances of many species falling between ca. 11,000-10,000 14C yr BP. Temporally, this period overlaps with the Clovis Paleoindian cultural complex (11,190-10,530 14C yr BP) and with sudden climatic changes that define the beginning of the Younger Dryas chronozone (ca. 11,000-10,000 14C yr BP), both of which have been considered as potential proximal causes of this extinction event. Radiocarbon dating of enamel and filtered bone collagen from an extinct American Mastodon ( Mammut americanum) from northern Indiana, USA, by accelerator mass spectrometer yielded direct dates of 10,055 ± 40 14C yr BP and 10,032 ± 40 14C yr BP, indicating that the animal survived beyond the Clovis time period and into the late Younger Dryas. Although the late survival of this species in mid-continental North America does not remove either humans or climatic change as contributing causes for the late Pleistocene extinctions, neither Clovis hunters nor the climatic perturbations initiating the Younger Dryas chronozone were immediately responsible for driving mastodons to extinction.

  19. Reconnaissance of the Black River, a cold-water river in the north-central part of Michigan's southern peninsula

    USGS Publications Warehouse

    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

  20. Continuous wavelet transform and Euler deconvolution method and their application to magnetic field data of Jharia coalfield, India

    NASA Astrophysics Data System (ADS)

    Singh, Arvind; Singh, Upendra Kumar

    2017-02-01

    This paper deals with the application of continuous wavelet transform (CWT) and Euler deconvolution methods to estimate the source depth using magnetic anomalies. These methods are utilized mainly to focus on the fundamental issue of mapping the major coal seam and locating tectonic lineaments. The main aim of the study is to locate and characterize the source of the magnetic field by transferring the data into an auxiliary space by CWT. The method has been tested on several synthetic source anomalies and finally applied to magnetic field data from Jharia coalfield, India. Using magnetic field data, the mean depth of causative sources points out the different lithospheric depth over the study region. Also, it is inferred that there are two faults, namely the northern boundary fault and the southern boundary fault, which have an orientation in the northeastern and southeastern direction respectively. Moreover, the central part of the region is more faulted and folded than the other parts and has sediment thickness of about 2.4 km. The methods give mean depth of the causative sources without any a priori information, which can be used as an initial model in any inversion algorithm.

  1. Genetic sequence relationships of Winnipegosis platform carbonates, southern Elk Point basin, North Dakota

    SciTech Connect

    Shanley, K.W.; Cross, T.A.

    1988-02-01

    Examination of cores and well log data from the Winnipegosis Formation (Givetian) within a study area of approximately 11,500 mi/sup 2/ (30,000 km/sup 2/) in northern North Dakota allows recognition of seven time-stratigraphic progradational units within the Winnipegosis Formation. Together with the underlying Ashern Formation, these units are arranged in landward-stepping, vertical stacking, and seaward-stepping geometric patterns, which reflect changes in relative sea level. Abrupt juxtaposition of shallow over deeper water lithologies, evidence for subaerial exposure, and onlap geometries further suggest that these progradational units form two larger, Vail-type sequences separated by regionally persistent unconformities or their correlative conformities.

  2. High-resolution and Deep Crustal Imaging Across The North Sicily Continental Margin (southern Tyrrhenian Sea)

    NASA Astrophysics Data System (ADS)

    Agate, M.; Bertotti, G.; Catalano, R.; Pepe, F.; Sulli, A.

    Three multichannel seismic reflection profiles across the North Sicily continental mar- gin have been reprocessed and interpreted. Data consist of an unpublished high pene- tration seismic profile (deep crust Italian CROP Project) and a high-resolution seismic line. These lines run in the NNE-SSW direction, from the Sicilian continental shelf to the Tyrrhenian abyssal plain (Marsili area), and are tied by a third, high penetration seismic line MS104 crossing the Sisifo High. The North Sicily continental margin represents the inner sector of the Sicilian-Maghrebian chain that is collapsed as con- sequence of extensional tectonics. The chain is formed by a tectonic wedge (12-15 km thick. It includes basinal Meso-Cenozoic carbonate units overthrusting carbonate platform rock units (Catalano et al., 2000). Presently, main culmination (e.g. Monte Solunto) and a number of tectonic depressions (e.g. Cefalù basin), filled by >1000 m thick Plio-Pleistocene sedimentary wedge, are observed along the investigated tran- sect. Seismic attributes and reflector pattern depicts a complex crustal structure. Be- tween the coast and the M. Solunto high, a transparent to diffractive band (assigned to the upper crust) is recognised above low frequency reflective layers (occurring be- tween 9 and 11 s/TWT) that dips towards the North. Their bottom can be correlated to the seismological (African?) Moho discontinuity which is (26 km deep in the Sicilian shelf (Scarascia et al., 1994). Beneath the Monte Solunto ridge, strongly deformed re- flectors occurring between 8 to 9.5 s/TWT (European lower crust?) overly the African (?) lower crust. The resulting geometry suggests underplating of the African crust respect to the European crust (?). The already deformed crustal edifice is dissected by a number of N-dipping normal faults that open extensional basins and are associ- ated with crustal thinning. The Plio-Pleistocene fill of the Cefalù basin can be subdi- vided into three subunits by

  3. Family Obligation Across Contexts: Hispanic Youth in North Carolina and Southern California

    PubMed Central

    Yahirun, Jenjira J.; Perreira, Krista M.; Fuligni, Andrew J.

    2013-01-01

    Over the past decade, the Hispanic population has grown in areas with little to no history of recent immigration. Prior research comparing Hispanics in new and established destinations has chiefly focused on differences in socioeconomic indicators of assimilation. Our paper departs from this work by shifting the focus to sociocultural outcomes. Specifically, we use data from Los Angeles and North Carolina to examine differences in the strength of family obligation (N=552). We find that demographic characteristics explain all of the geographic difference in family obligation between these locations. However, we also find that co-ethnic concentration is positively correlated with adolescents’ endorsement of future family support, once ethnic identity is included in the analysis. PMID:26146429

  4. Unraveling the complex local-scale flows influencing ozone patterns in the southern Great Lakes of North America

    NASA Astrophysics Data System (ADS)

    Levy, I.; Makar, P. A.; Sills, D.; Zhang, J.; Hayden, K. L.; Mihele, C.; Narayan, J.; Moran, M. D.; Sjostedt, S.; Brook, J.

    2010-08-01

    This study examines the complexity of various processes influencing summertime ozone levels in the southern Great Lakes region of North America. Results from the Border Air Quality and Meteorology (BAQS-Met) field campaign in the summer of 2007 are examined with respect to land-lake differences and local meteorology using a large array of ground-based measurements, aircraft data and simulation results from a high resolution (2.5 km) regional air-quality model, AURAMS. Analyses of average ozone mixing ratio from the entire BAQS-Met intensive campaign period support previous findings that ozone levels are higher over the southern Great Lakes than over the adjacent land. However, there is great heterogeneity in the spatial distribution of surface ozone over the lakes, particularly over Lake Erie during the day, with higher levels located over the southwestern end of the lake. Results suggest that some of these increased ozone levels are due to local emission sources in large nearby urban centers. The land-lake differences in ozone mixing ratios are most pronounced during the night in a shallow inversion layer of about 200 m above the surface. After sunrise, these differences have a limited effect on the total mass of ozone over the lakes during the day time, though they may cause elevated ozone levels in the lake breeze air. A large reservoir layer of ozone is predicted by the AURAMS model over Lake Erie at night, centered between 600-1000 m above ground and extending into the land over Cleveland. The model also predicts a vertical circulation during the day with an updraft over Detroit-Windsor and downdraft over Lake St. Clair, which transports ozone up to 1500 m above ground and results in high ozone over the lake. Oscillations in ground level ozone mixing ratios were observed on several nights and several ground monitoring sites, with amplitudes of up to 40 ppbv and time periods of 15-40 min.

  5. Bottom water changes in the subtropical North Atlantic and the Southern Ocean associated to the Middle Eocene Climatic Optimum

    NASA Astrophysics Data System (ADS)

    Moebius, I.; Friedrich, O.; Edgar, K. M.; Scher, H. D.; Sexton, P.

    2013-12-01

    The Middle Eocene Climatic Optimum (MECO) is a ~650 kyr interval of pronounced global warmth from which the climate system recovered in less than 50 kyr. Despite the valuable insights that the deep-sea sedimentary record could provide on the benthic ecosystem response to this protracted global warming event, and the mechanisms responsible for its relatively rapid recovery, we have little understanding of either. Here we present new data on bottom-water characteristics from ODP Sites 1051 (subtropical North Atlantic) and 738 (Southern Ocean), spanning the MECO and post-MECO interval (41.1 to 39.5 Ma). At Site 1051 we used benthic foraminiferal assemblages and benthic foraminifera accumulation rates (BFAR). We find little change in the species composition, but we identify two transient intervals of BFARs increasing by one order of magnitude associated with peak warming: High Productivity Intervals HPI-1 (40.07 - 39.98 Ma) and HPI-2 (39.70 - 39.62 Ma). We correlate these HPIs to intervals of increased organic carbon burial found in the Tethys and suggest that they represent periods of strengthened productivity in the subtropical North Atlantic and the Tethys. At Southern Ocean Site 738 we used benthic foraminiferal assemblages in combination with Cerium-anomaly data. In contrast to Site 1051, we notice a turnover of the benthic foraminiferal communities during the MECO (40.60 and 39.95 Ma) towards an assemblage dominated by infaunal taxa indicative of eutrophication. Additionally, we observe a drop in benthic foraminiferal abundances during the peak warming (40.10 - 39.97 Ma), synchronous to a low Cerium-anomaly and small excursion in ɛNd values. This indicates a decrease in bottom-water oxygenation during MECO peak warming, potentially caused by the transient influence of an older, oxygen-depleted water mass. Overall, our data suggest that the extent and rate of environmental change associated with the MECO vary greatly in different ocean basins and that the

  6. The tectonic crustal stress field and style of faulting along the Pacific North America Plate boundary in Southern California

    NASA Astrophysics Data System (ADS)

    Yang, Wenzheng; Hauksson, Egill

    2013-07-01

    We invert for the state of stress in the southern California crust using a catalogue of high quality earthquake focal mechanisms (1981-2010). The stress field is best resolved where seismicity rates are high and sufficient data are available to constrain the stress field across most of the region. From the stress field, we determine the maximum horizontal compressive stress (SHmax) orientations and the style of faulting across southern California. The trend of SHmax exhibits significant regional and local spatial heterogeneities. The regional trend of SHmax varies from north along the San Andreas system to NNE to the east in the Eastern California Shear Zone as well as to the west, within the Continental Borderland and the Western Transverse Ranges. The transition zones from one state of stress to the other occur over a distance of only a few kilometres, following a trend from Yucca Valley to Imperial Valley to the east, and the western edge of the Peninsular Ranges to the west. The local scale heterogeneities in the SHmax trend include NNW trends along the San Andreas Fault near Cajon Pass, Tejon Pass and the Cucapah Range, as well as NNE trends near the northern San Jacinto Fault and the Wheeler Ridge area. The style of faulting exhibits similar complexity, ranging from predominantly normal faulting in the high Sierra Nevada, to strike-slip faulting along the San Andreas system, to three consecutive bands of thrust faulting in the Wheeler Ridge area and the Western Transverse Ranges. The local variations in the style of faulting include normal faulting at the north end of the San Jacinto Fault and scattered areas of thrust faulting. The regional variations in the SHmax trends are very similar to the pattern of the GPS-measured maximum shortening axes of the surface strain rate tensor field although the strain field tends to be smoother and appears to capture some of the upper-mantle deformation field. The mean trend of SHmax departs about approximately 14° to

  7. Color-blindness in Calabria (Southern Italy): A north-south decreasing trend.

    PubMed

    Tagarelli, A.; Piro, A.; Tagarelli, G.; Zinno, F.

    2000-01-01

    The frequency of color-blindness (CB) in 13,072 males from 409 towns in Calabria is 5.42%. Regional variation in CB within the three provinces of Calabria was studied: Cosenza (northern), Catanzaro (central), and Reggio Calabria (southern). There is a decreasing trend of mean frequencies of CB from Cosenza to Reggio Calabria through Catanzaro: 6.23%, 4.65%, and 3.43%, respectively. The mean frequencies do not take into account the two ethnic minorities present in Calabria: Albanians and Grecanicans. The frequency of CB mean Albanians (7.40%) and the indigenous Calabrian population (5.25%) differs significantly. Moreover, the Albanians do not show the protoanomalous phenotype. The small sample size of Grecanicans does not permit an evaluation of mean CB frequency. Thus, from the perspective of CB, the Calabria region may be considered a mixture of "genetic isolates" reflecting its historical, sociocultural, demographic, and genetic features. Am. J. Hum. Biol. 12:17-24, 2000. Copyright 2000 Wiley-Liss, Inc.

  8. Significant Threat to North American forests from Southern Pine Beetle with Warming Winters

    NASA Astrophysics Data System (ADS)

    Horton, R. M.; Lesk, C.; Coffel, E.; D'Amato, A. W.

    2016-12-01

    In coming decades, warmer winters are likely to lift range constraints on many cold-limited forest insects. Recent unprecedented expansion of the southern pine beetle (SPB, Dendroctonus frontalis) into New Jersey, New York, Connecticut, and Massachusetts in concert with warming annual temperature minima highlights the risk that this insect pest poses to the pine forests of the northern United States and Canada under continued climate change. Here we present the first projections of northward expansion in SPB-suitable climates using a statistical bioclimatic range modeling approach and current-generation general circulation model (GCM) output under the RCP 4.5 and 8.5 emissions scenarios. Our results show that by the middle of the 21st century, the climate is likely to be suitable for SPB expansion into vast areas of previously unaffected forests throughout the northeastern United States and into southeastern Canada. This scenario would pose a significant economic and ecological risk to the affected regions, including disruption of local ecosystem services, dramatic shifts in forest structure, and threats to native biodiversity.

  9. An atmosphere-wave regional coupled model: improving predictions of wave heights and surface winds in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Wahle, Kathrin; Staneva, Joanna; Koch, Wolfgang; Fenoglio-Marc, Luciana; Ho-Hagemann, Ha T. M.; Stanev, Emil V.

    2017-04-01

    The coupling of models is a commonly used approach when addressing the complex interactions between different components of earth systems. We demonstrate that this approach can result in a reduction of errors in wave forecasting, especially in dynamically complicated coastal ocean areas, such as the southern part of the North Sea - the German Bight. Here, we study the effects of coupling of an atmospheric model (COSMO) and a wind wave model (WAM), which is enabled by implementing wave-induced drag in the atmospheric model. The numerical simulations use a regional North Sea coupled wave-atmosphere model as well as a nested-grid high-resolution German Bight wave model. Using one atmospheric and two wind wave models simultaneously allows for study of the individual and combined effects of two-way coupling and grid resolution. This approach proved to be particularly important under severe storm conditions as the German Bight is a very shallow and dynamically complex coastal area exposed to storm floods. The two-way coupling leads to a reduction of both surface wind speeds and simulated wave heights. In this study, the sensitivity of atmospheric parameters, such as wind speed and atmospheric pressure, to the wave-induced drag, in particular under storm conditions, and the impact of two-way coupling on the wave model performance, is quantified. Comparisons between data from in situ and satellite altimeter observations indicate that two-way coupling improves the simulation of wind and wave parameters of the model and justify its implementation for both operational and climate simulations.

  10. Organochlorines in benthic polychaetes (Nephtys Spp.) and sediments from the southern North Sea. identification of individual PCB components

    NASA Astrophysics Data System (ADS)

    Boon, J. P.; Van Zantvoort, M. B.; Govaert, M. J. M. A.; Duinker, J. C.

    ΣPCB concentrations (as the sum of concentrations of 35 individual components) on a lipid basis varied more than an order of magnitude between samples of polychaete worms ( Nephtys spp.) from different stations in the southern North Sea. PCB patterns, i.e. the relative contribution of each component to ΣPCB, were highly similar for the larger part of the area. The geographical differences between concentrations of PCB's reflected the general routes of residual water and suspended particulate matter transport throughout the North Sea. The Rhine is likely to be the main source for PCB's in Dutch coastal waters, including the entire coastline formed by the Dutch Wadden Sea islands. Theoretical patterns of PCB's in solution were calculated from the PCB patterns in Nepthys and values of bioconcentration factors reported. Concentrations of HCB, α- and γ-HCH, dieldrin, p,p'-DDD and p,p'-DDT were at least an order of magnitude lower and close to, or even below, detection limit in most samples. Although concentrations of α-and γ-HCH in solution were the highest of the compounds investigated, their concentrations in Nephtys were among the lowest, which might have been due to their relatively high solubility in water, or metabolism to more polar derivatives. Based on total sediment analyses, organochlorine concentrations in Nephtys spp. were not correlated with the concentrations in the (type of) sediment which they inhabited. In sediments the fraction of grains <63 μm appeared to be very important. A sewer outlet near Grimsby (U.K.) was found to be a source for HCB and Σ-DDT.

  11. Crustal structure north of the Taiping Island (Itu Aba Island), southern margin of the South China Sea

    NASA Astrophysics Data System (ADS)

    Chang, Jih-Hsin; Hsieh, Hsien-Hsiang; Mirza, Arif; Chang, Sung-Ping; Hsu, Ho-Han; Liu, Char-Shine; Su, Chih-Chieh; Chiu, Shye-Donq; Ma, Yu-Fang; Chiu, Ying-Hui; Hung, Hau-Ting; Lin, Yen-Chun; Chiu, Chien-Hsuan

    2017-07-01

    Based on the multi-channel seismic (MCS) and gravity data offshore north of Taiping Island (Itu Aba Island) in the Spratly Islands (Nansha Islands), we revisited the crustal structures in the northern part of the southern margin of the Southwest (SW) Sub-basin of the South China Sea (SCS). The MCS data suggest that the basement structural highs in the southwest margin of the SCS are dominated by both fault blocks and volcanic basement structures that probably formed along with the basement faults. The gravity modeling results reveal that these volcanic basement structures were probably associated with the high velocity or density lower crust (HVDLC), suggesting that the southern margin of the SW Sub-basin serves as an intermediate margin. Based on the tectonic features in the SCS margins, including (1) the transition between the magma-poor margins of the Northwest (NW) Sub-basin and intermediate margins of the East and SW Sub-basins; (2) the cessation of the seafloor spreading in the NW Sub-basin being succeeded by a major ridge jump event, which was very likely to reflect an active mantle upwelling event; (3) the extensive distribution of the HVDLC beneath in the well-investigated northern margin of the East Sub-basin and as explored in the SW Sub-basin in this study; and (4) basement faulting and volcanism shown in this study that may be related to the HVDLC and hyper-extension, we proposed a conceptual model to interpret the origin of the HVDLC in the southern margin of the SW Sub-basin. The margin of the SCS basin was magma-poor at the time it occurred. An active mantle upwelling event caused by small-scale mantle convection, possibly related to the influence of the nascent Hainan mantle plume, was formed subsequently, resulting in a southward ridge jump and the HVDLC beneath the current margins of the East and SW Sub-basins. The East and SW Sub-basins continued to spread, latitudinally dividing their HVDLCs as the margins separated accordingly. Afterwards, the

  12. New insights into North America-Pacific Plate boundary deformation from Lake Tahoe, Salton Sea and southern Baja California

    NASA Astrophysics Data System (ADS)

    Brothers, Daniel Stephen

    Five studies along the Pacific-North America (PA-NA) plate boundary offer new insights into continental margin processes, the development of the PA-NA tectonic margin and regional earthquake hazards. This research is based on the collection and analysis of several new marine geophysical and geological datasets. Two studies used seismic CHIRP surveys and sediment coring in Fallen Leaf Lake (FLL) and Lake Tahoe to constrain tectonic and geomorphic processes in the lakes, but also the slip-rate and earthquake history along the West Tahoe-Dollar Point Fault. CHIRP profiles image vertically offset and folded strata that record deformation associated with the most recent event (MRE). Radiocarbon dating of organic material extracted from piston cores constrain the age of the MRE to be between 4.1--4.5 k.y. B.P. Offset of Tioga aged glacial deposits yield a slip rate of 0.4--0.8 mm/yr. An ancillary study in FLL determined that submerged, in situ pine trees that date to between 900-1250 AD are related to a medieval megadrought in the Lake Tahoe Basin. The timing and severity of this event match medieval megadroughts observed in the western United States and in Europe. CHIRP profiles acquired in the Salton Sea, California provide new insights into the processes that control pull-apart basin development and earthquake hazards along the southernmost San Andreas Fault. Differential subsidence (>10 mm/yr) in the southern sea suggests the existence of northwest-dipping basin-bounding faults near the southern shoreline. In contrast to previous models, the rapid subsidence and fault architecture observed in the southern part of the sea are consistent with experimental models for pull-apart basins. Geophysical surveys imaged more than 15 ˜N15°E oriented faults, some of which have produced up to 10 events in the last 2-3 kyr. Potentially 2 of the last 5 events on the southern San Andreas Fault (SAF) were synchronous with rupture on offshore faults, but it appears that ruptures on

  13. Evidence of Carboniferous volcanic ash in Pictou Group (West-phalian D), Sydney Coalfield, Nova Scotia, Canada

    SciTech Connect

    Lyons, P.C.; Outerbridge, W.F. ); Hacquebard, P.A. )

    1991-08-01

    Until now, Carboniferous-altered volcanic ash in North America was known only from the Middle Pennsylvanian (upper Westphalian A to lower Westphalian D) of the Appalachian basin. Now, however, mineralogical analysis of thin claystones (8-24 mm thick) in mineable bituminous coal (Hub and Harbour seams) form the P-boreholes in the Donkin submarine areas of the Sydney coalfield, Nova Scotia, indicates the presence of trace amounts of minerals probably derived from a volcanic ash fall of late Westphalian D age. Water-clear to cloudy quartz splinters and euhedral zircon with sharp crystal faces and edges, and length-to-width ratios up to 6:1 - which are typical of Appalachian altered acidic volcanic ash deposits (tonsteins) - were with a dominantly detrital (fluvial ) mineral suite. Fifty to 90% water-laid silt- to sand-size detrital grains of quartz, tourmaline( ), zircon, white mica, and other minerals are found in the HF residum after the removal of the dominant components: clay minerals, pyrite, and coal particles (spores, secretinite, etc.). The fine size of the volcanic minerals and their low concentration indicate a very distant volcanic ash source, perhaps western Europe, where volcanic activity extended into the Stephanian.

  14. Genetic sequence relationships of Winnipegosis platform carbonates, southern Elk Point basin, North Dakota

    SciTech Connect

    Shanley, K.W.; Cross, T.A.

    1988-01-01

    Examination of cores and well log data from the Winnipegosis Formation (Givetian) within a study area of approximately 11,500 mi/sup 2/ (30,000 km/sup 2/) in northern North Dakota allows recognition of seven time-stratigraphic progradational units within the Winnipegosis Formation. Together with the underlying Ashern Formation, these units are arranged in landward-stepping, vertical stacking, and seaward-stepping geometric patterns, which reflect changes in relative sea level. Abrupt juxtaposition of shallow over deeper water lithologies, evidence for subaerial exposure, and onlap geometries further suggest that these progradational units form two larger, Vail-type sequences separated by regionally persistent unconformities or their correlative conformities. Sea level rise during the early Eifelian caused southeastward onlap of the Ashern Formation onto Middle Silurian carbonates of the Interlake Formation. Maximum flooding, expressed by deepest marine facies and a hardground surface, suggests the existence of a condensed section at the top of the Ashern Formation. This was developed during the maximum rate of sea level rise. A decrease in the rate of sea level rise resulted in aggradation of lower Winnipegosis units on a gently dipping ramp. These are represented by nodular and burrowed open marine limestones with scattered stromatoporoid patch reefs and grainstone shoals. During the subsequent sea level fall, represented by Temple units, a shelf margin with pronounced depositional topography and adjacent starved basin were developed. Temple strata include coral-brachiopod-stromatoporoid reefs and productive fore-reef talus deposits along the shelf margin rim.

  15. Reconnaissance of the Sturgeon River, a cold-water river in the north-central part of Michigan's southern peninsula

    USGS Publications Warehouse

    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

  16. Influence of the North American monsoon on Southern California tropospheric ozone levels during summer in 2013 and 2014

    NASA Astrophysics Data System (ADS)

    Granados-Muñoz, Maria Jose; Johnson, Matthew S.; Leblanc, Thierry

    2017-06-01

    The impact of the North American (NA) monsoon on tropospheric ozone variability in Southern California is investigated using lidar measurements at Jet Propulsion Laboratory-Table Mountain Facility, California, and the chemical-transport model GEOS-Chem. Routine lidar observations obtained in July-August 2013-2014 reveal a consistent ozone enhancement of 23 ppbv in the free troposphere (6-9 km), when ozone-rich air is transported along the western edge of the upper level anticyclone associated with the NA monsoon from regions where maximum lightning-induced NOx production occurs. When the high-pressure system shifts to the southeast, a zonal westerly flow of the air parcels reaching the Table Mountain Facility (TMF) occurs, prohibiting the lightning-induced ozone enhanced air to reach TMF. This modulation of tropospheric ozone by the position of the NA monsoon anticyclone could have implications on long-term ozone trends associated with our changing climate, due to the expected widening of the tropical belt affecting the strength and position of the anticyclone.

  17. Hydro-meteorological influences and multimodal suspended particle size distributions in the Belgian nearshore area (southern North Sea)

    NASA Astrophysics Data System (ADS)

    Fettweis, Michael; Baeye, Matthias; Lee, Byung Joon; Chen, Peihung; Yu, Jason C. S.

    2012-04-01

    Suspended particulate matter (SPM) concentration and particle size distribution (PSD) were assessed in a coastal turbidity maximum area (southern North Sea) during a composite period of 37 days in January-April 2008. PSDs were measured with a LISST 100X and classified using entropy analysis in terms of subtidal alongshore flow. The PSDs during tide-dominated conditions showed distinct multimodal behaviour due to flocculation, revealing that the building blocks of flocs consist of primary particles (<3 μm) and flocculi (15 μm). Flocculi comprise clusters of clay minerals, whereas primary particles have various compositions (calcite, clays). The PSDs during storms with a NE-directed alongshore subtidal current (NE storms) are typically unimodal and characterised by mainly granular material (silt, sand) resuspended from the seabed. During storms with a SW-directed alongshore subtidal current (SW storms), by contrast, mainly flocculated material can be identified in the PSDs. The findings emphasise the importance of wind-induced advection, alongshore subtidal flow and highly concentrated mud suspensions (HCMSs) as regulating mechanisms of SPM concentration, as well as other SPM characteristics (cohesiveness or composition of mixed sediment particles) and size distribution in a high-turbidity area. The direction of subtidal alongshore flow during SW storm events results in an increase in cohesive SPM concentration, HCMS formation, and the armouring of sand; by contrast, there is a decrease in cohesive SPM concentration, no HCMS formation, and an increase in sand and silt in suspension during NE storms.

  18. Historical changes in carbon dioxide (CO2) and dimethyl sulphide (DMS) emissions in the eutrophied Southern North Sea

    NASA Astrophysics Data System (ADS)

    Gypens, N.; Borges, A. V.; Lancelot, C.

    2012-04-01

    Anthropogenic activities after the Second World War have severely increased river nutrient [nitrogen (N) and phosphorus (P)] loads to European coastal areas. The resulting N: P: Si imbalance (compared to phytoplankton requirements) stimulated in the Southern North Sea the growth of Phaeocystis colonies modifying the functioning of the ecosystem and, therefore, the carbon but also the biogenic sulphur cycles. Phaeocystis is a significant producer of DMSP (dimethylsulphide propionate), the precursor of DMS. When emitted to the atmosphere the DMS has a cooling effect on the climate contrarily to the CO2 greenhouse gas. Since the late 1990's specific nutrient reduction policies have however considerably reduced P loads while N is maintained. In this application we explore, with a mathematical tool, the effects of changing N and P loads on air-sea CO2 exchanges and DMS marine emissions. The chosen model is the MIRO-CO2-DMS, a complex biogeochemical model describing carbon, biogenic sulphur and nutrient cycles in the marine domain. Model simulations are performed for the contemporary period since 1950, using real forcing fields for sea surface temperature, wind speed and atmospheric CO2 and RIVERSTRAHLER model simulations for river carbon and nutrient loads. Results are discussing the importance of human activities and river inputs of carbon and nutrients on the eutrophication of coastal areas, their ability to absorb atmospheric CO2 and the importance of DMS emissions associated with phytoplankton blooms, especially Phaeocystis.

  19. Distribution of total mercury in surface sediments of the western Jade Bay, Lower Saxonian Wadden Sea, southern North Sea.

    PubMed

    Jin, Huafang; Liebezeit, Gerd; Ziehe, Daniel

    2012-04-01

    A total of 114 surface sediment samples was equidistantly collected in the western part of the Jade Bay, southern North Sea, to analyse total mercury contents as well as grain size distribution and total organic carbon (TOC) contents. Total mercury was determined by oxygen combustion-gold amalgamation. Validation, precision and accuracy of the method were evaluated and controlled with two certified reference materials (HISS-1 and MESS-3). Total mercury contents varied between 8 and 243 ng/g dry sediment with a mean value of 103 ng/g dw. The mercury levels in surface sediments showed an inhomogeneous spatial distribution with higher contents in near-dike areas. The values are mostly in the range of natural background values (50–100 ng/g dw) and positively related to TOC and clay/silt contents (<63 μm). The present total mercury contents are compared to those of previous studies, in order to estimate possible temporal trends of mercury contents in the study area over the last decades. Moreover, the comparison to sediment quality guidelines indicated that the surface sediments of the Jade Bay are not mercury contaminated. These results also suggested that the current mercury contents of Jade Bay surficial sediments are mostly affected by atmospheric deposition and re-emission.

  20. Chronic Diseases in North-West Tanzania and Southern Uganda. Public Perceptions of Terminologies, Aetiologies, Symptoms and Preferred Management

    PubMed Central

    Nnko, Soori; Bukenya, Dominic; Kavishe, Bazil Balthazar; Biraro, Samuel; Peck, Robert; Kapiga, Saidi; Grosskurth, Heiner; Seeley, Janet

    2015-01-01

    Background Research has shown that health system utilization is low for chronic diseases (CDs) other than HIV. We describe the knowledge and perceptions of CDs identified from rural and urban communities in north-west Tanzania and southern Uganda. Methods Data were collected through a quantitative population survey, a quantitative health facility survey and focus group discussions (FGDs) and in-depth interviews (IDIs) in subgroups of population survey participants. The main focus of this paper is the findings from the FGDs and IDIs. Results We conducted 24 FGDs, involving approximately 180 adult participants and IDIs with 116 participants (≥18 years). CDs studied included: asthma/chronic obstructive lung disease (COPD), diabetes, epilepsy, hypertension, cardiac failure and HIV- related disease. The understanding of most chronic conditions involved a combination of biomedical information, gleaned from health facility visits, local people who had suffered from a complaint or knew others who had and beliefs drawn from information shared in the community. The biomedical contribution shows some understanding of the aetiology of a condition and the management of that condition. However, local beliefs for certain conditions (such as epilepsy) suggest that biomedical treatment may be futile and therefore work counter to biomedical prescriptions for management. Conclusion Current perceptions of selected CDs may represent a barrier that prevents people from adopting efficacious health and treatment seeking behaviours. Interventions to improve this situation must include efforts to improve the quality of existing health services, so that people can access relevant, reliable and trustworthy services. PMID:26555896

  1. GPS tracking data of Lesser Black-backed Gulls and Herring Gulls breeding at the southern North Sea coast.

    PubMed

    Stienen, Eric W M; Desmet, Peter; Aelterman, Bart; Courtens, Wouter; Feys, Simon; Vanermen, Nicolas; Verstraete, Hilbran; de Walle, Marc Van; Deneudt, Klaas; Hernandez, Francisco; Houthoofdt, Robin; Vanhoorne, Bart; Bouten, Willem; Buijs, Roland-Jan; Kavelaars, Marwa M; Müller, Wendt; Herman, David; Matheve, Hans; Sotillo, Alejandro; Lens, Luc

    2016-01-01

    In this data paper, Bird tracking - GPS tracking of Lesser Black-backed Gulls and Herring Gulls breeding at the southern North Sea coast is described, a species occurrence dataset published by the Research Institute for Nature and Forest (INBO). The dataset (version 5.5) contains close to 2.5 million occurrences, recorded by 101 GPS trackers mounted on 75 Lesser Black-backed Gulls and 26 Herring Gulls breeding at the Belgian and Dutch coast. The trackers were developed by the University of Amsterdam Bird Tracking System (UvA-BiTS, http://www.uva-bits.nl). These automatically record and transmit bird movements, which allows us and others to study their habitat use and migration behaviour in great detail. Our bird tracking network is operational since 2013. It is funded for LifeWatch by the Hercules Foundation and maintained in collaboration with UvA-BiTS and the Flanders Marine Institute (VLIZ). The recorded data are periodically released in bulk as open data (http://dataset.inbo.be/bird-tracking-gull-occurrences), and are also accessible through CartoDB and the Global Biodiversity Information Facility (GBIF).

  2. Relationships between ground and airborne gamma-ray spectrometric survey data, North Ras Millan, Southern Sinai Peninsula, Egypt.

    PubMed

    Youssef, Mohamed A S

    2016-02-01

    In the last decades of years, there was considerable growth in the use of airborne gamma-ray spectrometry. With this growth, there was an increasing need to standardize airborne measurements, so that they can be independent of survey parameters. Acceptable procedures were developed for converting airborne to ground gamma-ray spectrometric measurements of total-count intensity as well as, potassium, equivalent uranium and equivalent thorium concentrations, due to natural sources of radiation. The present study aims mainly to establish relationships between ground and airborne gamma-ray spectrometric data, North Ras Millan, Southern Sinai Peninsula, Egypt. The relationships between airborne and ground gamma-ray spectrometric data were deduced for the original and separated rock units in the study area. Various rocks in the study area, represented by Quaternary Wadi sediments, Cambro-Ordovician sandstones, basic dykes and granites, are shown on the detailed geologic map. The structures are displayed, which located on the detailed geologic map, are compiled from the integration of previous geophysical and surface geological studies.

  3. Impact factors identification of spatial heterogeneity of herbaceous plant diversity on five southern islands of Miaodao Archipelago in North China

    NASA Astrophysics Data System (ADS)

    Chi, Yuan; Shi, Honghua; Wang, Xiaoli; Qin, Xuebo; Zheng, Wei; Peng, Shitao

    2016-09-01

    Herbaceous plants are widely distributed on islands and where they exhibit spatial heterogeneity. Accurately identifying the impact factors that drive spatial heterogeneity can reveal typical island biodiversity patterns. Five southern islands in the Miaodao Archipelago, North China were studied herein. The spatial distribution of herbaceous plant diversity on these islands was analyzed, and the impact factors and their degree of impact on spatial heterogeneity were identified using CCA ordination and ANOVA. The results reveal 114 herbaceous plant species, belonging to 94 genera from 34 families in the 50 plots sampled. The total species numbers on different islands were significantly positively correlated with island area, and the average α diversity was correlated with human activities, while the β diversity among islands was more affected by island area than mutual distances. Spatial heterogeneity within islands indicated that the diversities were generally high in areas with higher altitude, slope, total nitrogen, total carbon, and canopy density, and lower moisture content, pH, total phosphorus, total potassium, and aspect. Among the environmental factors, pH, canopy density, total K, total P, moisture content, altitude, and slope had significant gross effects, but only canopy density exhibited a significant net effect. Terrain affected diversity by restricting plantation, plantation in turn influenced soil properties and the two together affected diversity. Therefore, plantation was ultimately the fundamental driving factor for spatial heterogeneity in herbaceous plant diversity on the five islands.

  4. Impact of coastal defence structures (tetrapods) on a demersal hard-bottom fish community in the southern North Sea.

    PubMed

    Wehkamp, Stephanie; Fischer, Philipp

    2013-02-01

    In the coming decades, artificial defence structures will increase in importance worldwide for the protection of coasts against the impacts of global warming. However, the ecological effects of such structures on the natural surroundings remain unclear. We investigated the impact of experimentally introduced tetrapod fields on the demersal fish community in a hard-bottom area in the southern North Sea. The results indicated a significant decrease in fish abundance in the surrounding area caused by migration effects towards the artificial structures. Diversity (HB) and evenness (E) values exhibited greater variation after the introduction of the tetrapods. Additionally, a distinct increase in young-of-the-year (YOY) fish was observed near the structures within the second year after introduction. We suggest that the availability of adequate refuges in combination with additional food resources provided by the artificial structures has a highly species-specific attraction effect. However, these findings also demonstrate that our knowledge regarding the impact of artificial structures on temperate fish communities is still too limited to truly understand the ecological processes that are initiated by the introduction of artificial structures. Long-term investigations and additional experimental in situ work worldwide will be indispensable for a full understanding of the mechanisms by which coastal defence structures interact with the coastal environment.

  5. A geophysical overview of the southern continental margin of North America in the Late Precambrian/Cambrian

    SciTech Connect

    Keller, G.R. . Dept. of Geological Sciences)

    1993-02-01

    Recent geophysical studies have shed considerable light on the nature and extent of the southern Continental margin of North America which formed during the Late Precambrian/Cambrian. To the east between Arkansas and Alabama, the PASSCAL/Ouachita seismic experiment and older results in Mississippi indicate that this margin is largely preserved beneath allochthonous rocks emplaced during the Ouachita orogeny. Here the margin is fairly abrupt suggesting transtension was important in this origin. The Wiggins and Sabine blocks appear to be continental fragments which may have formed along this margin. In Texas, the margin extends around the Llano uplift in a sinuous fashion. In this area, Mesozoic extension clouds the picture considerably. However, structural complexities along this portion of he margin can be inferred form gravity data. In West Texas, the margin bends westward and then southward. A very deep oil exploration test which was recently drilled in this area provides valuable constraints for geophysical models of this portion of the margin. Recent results in Mexico allows the authors to trace this margin further south into the state of Chihuahua than previously possible.

  6. Early Holocene environmental history of sunken landscapes: pollen, plant macrofossil and geochemical analyses from the Borkum Riffgrund, southern North Sea

    NASA Astrophysics Data System (ADS)

    Wolters, Steffen; Zeiler, Manfred; Bungenstock, Friederike

    2010-12-01

    A vibrocore from the sea floor of the southern North Sea provides a ~1,500-year record of early Holocene vegetation history and mire development in a landscape now 33 m below sea-level. Pollen, plant macrofossil and geochemical analyses of an AMS 14C dated sand-peat-marine mud sequence document the paludification on Pleistocene sands ~10,700 cal BP, the subsequent development of eutraphentic carr vegetation and the gradual inundation by the transgressing sea ~9,350 cal BP. Pinus- Corylus woodland prevailed on terrestrial grounds after hazel had immigrated ~10,700 cal BP. Salix dominated the carr vegetation throughout 1,300 years of peat formation, because Alnus did not spread in the Borkum Riffgrund area until 9,300 BP. Brackish reed vegetation with Phragmites established after inundation and siliciclastic marine sediments were being deposited. This article also examines the detection and suitability of key horizons indicative of marine influence. XRF-Scanning provides the most detailed results in the briefest possible time to pinpoint spectra best suitable for AMS 14C dating of classical key horizons such as start of peat formation and transgressive contact. The combined application of botanical and geochemical methods allows determining new key horizons indicative of marine influence, namely the earliest marine inundation and the onset of sea-level influence on coastal ground water level.

  7. GPS tracking data of Lesser Black-backed Gulls and Herring Gulls breeding at the southern North Sea coast

    PubMed Central

    Stienen, Eric W.M.; Desmet, Peter; Aelterman, Bart; Courtens, Wouter; Feys, Simon; Vanermen, Nicolas; Verstraete, Hilbran; de Walle, Marc Van; Deneudt, Klaas; Hernandez, Francisco; Houthoofdt, Robin; Vanhoorne, Bart; Bouten, Willem; Buijs, Roland-Jan; Kavelaars, Marwa M.; Müller, Wendt; Herman, David; Matheve, Hans; Sotillo, Alejandro; Lens, Luc

    2016-01-01

    Abstract In this data paper, Bird tracking - GPS tracking of Lesser Black-backed Gulls and Herring Gulls breeding at the southern North Sea coast is described, a species occurrence dataset published by the Research Institute for Nature and Forest (INBO). The dataset (version 5.5) contains close to 2.5 million occurrences, recorded by 101 GPS trackers mounted on 75 Lesser Black-backed Gulls and 26 Herring Gulls breeding at the Belgian and Dutch coast. The trackers were developed by the University of Amsterdam Bird Tracking System (UvA-BiTS, http://www.uva-bits.nl). These automatically record and transmit bird movements, which allows us and others to study their habitat use and migration behaviour in great detail. Our bird tracking network is operational since 2013. It is funded for LifeWatch by the Hercules Foundation and maintained in collaboration with UvA-BiTS and the Flanders Marine Institute (VLIZ). The recorded data are periodically released in bulk as open data (http://dataset.inbo.be/bird-tracking-gull-occurrences), and are also accessible through CartoDB and the Global Biodiversity Information Facility (GBIF). PMID:26877689

  8. A seasonal study of particulate organic matter composition and quality along an offshore transect in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Le Guitton, M.; Soetaert, K.; Sinninghe Damsté, J. S.; Middelburg, J. J.

    2017-03-01

    We investigated temporal differences in particulate organic matter (POM) composition and quality in the water column and sediment at three stations along a transect from the coast via Oyster Grounds to Dogger Bank within the southern North Sea, using a multiproxy approach covering a wide spectrum of organic matter (OM) degradation states. Results of pigments and phospholipid-derived fatty acids showed distinct OM composition and quality differences in these stations, as well as seasonal variations. Major events, such as a late fall bloom at Dogger Bank and a spring bloom at Oyster Grounds and the Coastal Station were highlighted and the semi-depositional status of Oyster Grounds was confirmed. The OM composition and quality were relatively constant in the upper 10 cm of the sediment at all stations. Finally, this study highlights the importance of lateral and vertical transport processes in seasonal variations in the biogeochemical carbon cycle in this area and the intense pre-depositional processing before eventual burial in coastal settings.

  9. A 3-D shear velocity model of the southern North American and Caribbean plates from ambient noise and earthquake tomography

    NASA Astrophysics Data System (ADS)

    Gaite, B.; Villaseñor, A.; Iglesias, A.; Herraiz, M.; Jiménez-Munt, I.

    2015-02-01

    We use group velocities from earthquake tomography together with group and phase velocities from ambient noise tomography (ANT) of Rayleigh waves to invert for the 3-D shear-wave velocity structure (5-70 km) of the Caribbean (CAR) and southern North American (NAM) plates. The lithospheric model proposed offers a complete image of the crust and uppermost-mantle with imprints of the tectonic evolution. One of the most striking features inferred is the main role of the Ouachita-Marathon-Sonora orogeny front on the crustal seismic structure of the NAM plate. A new imaged feature is the low crustal velocities along the USA-Mexico border. The model also shows a break of the east-west mantle velocity dichotomy of the NAM and CAR plates beneath the Isthmus of the Tehuantepec and the Yucatan Block. High upper-mantle velocities along the Mesoamerican Subduction Zone coincide with inactive volcanic areas while the lowest velocities correspond to active volcanic arcs and thin lithospheric mantle regions.

  10. A Lower Ordovician sponge/algal facies in the southern United States and its counterparts elsewhere in North America

    SciTech Connect

    Alberstadt, L. ); Repetski, J.E. )

    1989-06-01

    Subsurface Ordovician rocks in the Black Warrior Basin, Mississippi Embayment, and the eastern part of the Arkoma Basin reflect a different depositional history than coeval rocks exposed in the Nashville Basin, Ozark Dome, and southern Appalachians. The succession consists of four informal lithologic units. From top to bottom these are: (1) Stones River limestones, (2) upper dolostone, (3) sponge/algal limestones characterized by the presence of Nuia, and (4) lower dolostone. Of these, the sponge/algal limestone unit is the most atypical. It has a conspicuous biotic assemblage which can be recognized petrographically in well cuttings. The diagnostic fossil allochems are: sponges, sponge spicules, Nuia, Girvanella, and Sphaerocodium. Conodonts from the sponge/algal limestones are probably entirely Early Ordovician (Canadian) and include cold- and deep-water species found in the North Atlantic Province, whereas those in the overlying dolostones represent exclusively warm-water, shelf environments. The conodonts in the Black Warrior Basin suggest that an unconformity between Lower and Middle Ordovician carbonates (Knox unconformity) does not exist in much of that region. The sponge/algal limestones represent a different facies than their coeval shelf rocks in the interior of the continent. The limestone contains a distinctive biotic assemblage recognized in Lower Ordovician rocks in Newfoundland, in the Arbuckle and Wichita mountains of Oklahoma, in West Texas, and in the Great Basin of Nevada and Utah.

  11. Core handling, sedimentology, and petrophysical log response of a horizontal core, Barque field, United Kingdom sector, southern North Sea

    SciTech Connect

    Maskall, R. ); Reid, I. ); Urquhart, M. Shell U.K. Exploration and Production, Aberdeen )

    1994-03-01

    With the growing number of horizontal holes being drilled, petroleum geologists must handle increasing amounts of material having greater lateral than vertical extent. This requires novel techniques in description, interpretation, and data manipulation. This paper described the core handling and descriptive techniques used for a heterogeneous 28.6 m horizontal core from the eolian Rotliegende reservoir of the Barque gas field in the United Kingdom southern North Sea. The core is subparallel to structural dip, slowly cutting down stratigraphically but sampling only a limited extent (laterally or vertically) of the reservoir. One facies boundary can be traced for about 12 m along the core, and for a significant proportion of the core, two facies with markedly different reservoir properties occur across the same 10-cm core diameter. The core is unrepresentative of the reservoir, as described from vertical wells, in two ways: the overall lithofacies composition in the core is comparatively biased toward poor-quality (water-laid) facies, and the presence of a thin cemented layer in the normally better quality (eolian) facies markedly decreases their average porosity/permeability. Care must be taken in extrapolating plug data from the core to field models. Apparently, contradictory wireline responses are explained (through calibration to the core and by consideration of the physical basis of petrophysical log responses), allowing the construction of facies models covering the formation around the borehole. 14 refs., 11 figs., 3 tabs.

  12. A North American ammonite fauna from the late Middle Turonian of Vaucluse and Gard, southern France: the Romaniceras mexicanum, Prionocyclus hyatti and Coilopoceras cf. springeri association

    NASA Astrophysics Data System (ADS)

    Amédro, Francis; Robaszynski, Francis; Matrion, Bertrand; Devalque, Christian

    2016-12-01

    An unusual, exotic, ammonite fauna including Romaniceras mexicanum (Jones, 1938), Prionocyclus hyatti (Stanton, 1894) and Coilopoceras cf. springeri (Hyatt, 1903) is recorded from the late Middle Turonian of Vaucluse and Gard, southern France. It is the first record of this ammonite association outside the Gulf Coast region and the Western Interior of the United States of North America. Up to present, these species were considered as endemic to the Western Interior sea-way. The migration of numerous ammonites from North America to western Europe during the late Middle Turonian suggests it is linked to a transgressive event or to a short sea-level high.

  13. Genetic sequence relationships of Winnipegosis platform carbonates, Southern Elk Point basin, North Dakota

    SciTech Connect

    Shanley, K.W.; Cross, T.A.

    1988-07-01

    Examination of cores and well-log data from the Winnipegosis Formation (Givetian) within a study area of approximately 11,500 mi/sup 2/ (30,000 km/sup 2/) in northern North Dakota allows recognition of seven time-stratigraphic progradational units within the Winnipegosis Formation. Together with the underlying Ashern Formation, these units are arranged in landward-stepping, vertical stacking, and seaward-stepping geometric patterns, which reflect changes in relative sea level. Abrupt juxtaposition of shallow over deeper water lithologies, evidence for subaerial exposure, and onlap geometries further suggest that these progradational units form two larger Vail-type sequences separated by regionally persistent unconformities or their correlative conformities. Sea level rise during the early Eifelian caused southeastward onlap of the Ashern Formation onto Middle Silurian carbonates of the Interlake Formation. Maximum flooding, expressed by deepest marine facies and a hardground surface, suggests the existence of a condensed section at the top of the Ashern Formation. This section was developed during the maximum rate of sea level rise. A decrease in the rate of sea level rise resulted in aggradation of lower Winnipegosis units on a gently dipping ramp. These units are presented by nodular and burrowed open-marine limestones with scattered stromatoporoid patch reefs and grainstone shoals. During the subsequent sea level fall, represented by Temple units, a shelf margin with pronounced depositional topography and adjacent starved basin were developed. Temple strata include coral-brachiopod-stromatoporoid reefs and productive fore-reef talus deposits along the shelf-margin rim. With increased rates of sea level fall, the platform interior and shelf margin were subaerially exposed, slope carbonates were dolomitized, and the E-shale was deposited as a lowstand wedge.

  14. Ordovician platform, slope, and basin facies in subsurface of southern North America

    SciTech Connect

    Alberstadt, L.P.; Colvin, G.; Sauve, J.

    1986-05-01

    Ordovician carbonates of the Nashville dome and Ozark dome regions have long been considered typical shelf deposits. In the subsurface to the south, in the Black Warrior basin, Mississippi Embayment, and Arkoma basin, these shelf carbonate units changed facies. The most significant change is the occurrence of a thick limestone unit characterized by a faunal and floral assemblage of Nuia, Girvanella (isolated long strands), Sphaerocodium, a delicate stacked-chambered organism (.algal), and sponge spicules and sponge mudstone clumps. In ascending order, the complete Ordovician sequence consists of: a lower dolostone, the Nuia-sponge limestone, a dolostone, and a limestone. The upper part of this four-fold sequence changes character westward into the Arkoma basin. The lower two units maintain their character for long distances along depositional strike and occur in parts of the Appalachians as far north as Newfoundland, and on the opposite side of the continent in Nevada. The Nuia-sponge assemblage is a distinctive petrographic marker and seems to be a persistent Ordovician rock and fossil assemblage of widespread occurrence. In Nevada, it occurs on the surface where it is associated with slump and slide features that suggest that it is an outer shelf or upper slope deposit. Coeval carbonates in the Ouachita Mountains are different and show indications of being deep water (basinal). Biostratigraphic evidence indicates that the succession in the subsurface is continuous; the regional Lower Ordovician-Middle Ordovician unconformity is absent. The Lower Ordovician-Middle Ordovician boundary falls near the top of the Nuia-sponge mudstone unit and not at the top of the underlying thick dolostone unit.

  15. Efficiency of blue mussel (Mytilus edulis) spat collectors in highly dynamic tidal environments of the Lower Saxonian coast (southern North Sea).

    PubMed

    Walter, Uwe; Liebezeit, Gerd

    2003-07-01

    Traditional mussel culture in the Wadden Sea, southern North Sea, is carried out by taking seed mussels of about 1-4 cm shell length from natural beds and transplanting them to permanently water covered sites. Besides the damage done to the natural beds, the ratio of seeded to harvested mussels is only about 1:1-1.3, i.e. about the same tonnage of mussels seeded is recovered. In addition, this technique relies exclusively on natural spat falls, which do not occur regularly. In order to overcome these difficulties spat collectors have been deployed in the Jade Bay, southern North Sea. These provided suitable settlement grounds for mussel larvae. Blue mussel weights reached weights of about 8-9 kg/m collector rope with maximum shell lengths of 4-5 cm within one growing season.

  16. Geophysical and geologic studies in southern Mecklenburg County and vicinity, North Carolina and South Carolina

    USGS Publications Warehouse

    Wilson, Frederick A.

    1983-01-01

    Geophysical methods consisting of gravity, aeromagnetics and aeroradioactivity have been applied to part of the Charlotte and Carolina slate belts in southern Mecklenburg County and vicinity to help interpret geology, lithology and structure. High aeroradioactivity is associated with potassium-rich granitic plutons, muscovite-rich gneisses, schists, and metavolcanic rocks; positive gravity and magnetic anomalies are associated with gabbro plutons; and negative gravity anomalies are associated with granitic plutons. At the west side of the slate belt, the Tillery phyllite is interpreted as having undergone progressive metamorphism. The underlying Uwharrie Formation extends into the Charlotte belt where it is mapped as metavolcanic rocks. Gravity models of the Carolina slate belt indicate that it is a synform containing a wedge of metasedimentary and volcanoclastic rock on plutonic basement. The basement is exposed in the adjacent Charlotte belt antiform. The northern Charlotte belt contains mainly plutonic rocks which have been divided into 3 supergroups of plutons based upon chemistry, mineralogy, texture, and age. They are: 1. Old Plutonic supergroup - plutons 545-490 m.y. that are medium to coarse-grained tonalite, quartz diorite, and granodiorites. 2. Concord-Salisbury supergroup -- plutons 426-350 m.y. which form sheet-like intrusions of differentiated gabbro; local volcanic centers with ring complexes 13 km in diameter that suggest magma chambers 0 - 8 km deep; smaller bodies of diorite, monzonite, and syenite; and small Salisbury type granodiorites. 3. Landis supergroup -- plutons 350-280 m.y. that are usually very coarse-grained, porphyritic, 'big feldspar,' potassium-rich granites. The Mecklenburg-Weddington gabbro complex of the Concord-Salisbury supergroup, the largest feature in the study area, contains three large gabbro plutons. The gabbro intruded old Plutonic complex rocks and could-have produced the metamorphic reaction K-feldspar + sillimanite

  17. North Atlantic Deep Water export to the Southern Ocean over the past 14 Myr: Evidence from Nd and Pb isotopes in ferromanganese crusts

    USGS Publications Warehouse

    Frank, M.; Whiteley, N.; Kasten, S.; Hein, J.R.; O'Nions, K.

    2002-01-01

    The intensity of North Atlantic Deep Water (NADW) production has been one of the most important parameters controlling the global thermohaline ocean circulation system and climate. Here we present a new approach to reconstruct the overall strength of NADW export from the North Atlantic to the Southern Ocean over the past 14 Myr applying the deep water Nd and Pb isotope composition as recorded by ferromanganese crusts and nodules. We present the first long-term Nd and Pb isotope time series for deep Southern Ocean water masses, which are compared with previously published time series for NADW from the NW Atlantic Ocean. These data suggest a continuous and strong export of NADW, or a precursor of it, into the Southern Ocean between 14 and 3 Ma. An increasing difference in Nd and Pb isotope compositions between the NW Atlantic and the Southern Ocean over the past 3 Myr gives evidence for a progressive overall reduction of NADW export since the onset of Northern Hemisphere glaciation (NHG). The Nd isotope data allow us to assess at least semiquantitatively that the amount of this reduction has been in the range between 14 and 37% depending on location.

  18. Southern Cordilleran basaltic andesite suite, southern Chihuahua, Mexico: A link between Tertiary continental arc and flood basalt magmatism in North America

    NASA Astrophysics Data System (ADS)

    Cameron, K. L.; Nimz, G. J.; Kuentz, D.; Niemeyer, S.; Gunn, S.

    1989-06-01

    Mid-Cenozoic orogenic andesites and ignimbrites of western Mexico, southwestern New Mexico, and Arizona are commonly capped by basaltic andesites, most from 29-20 Ma. We refer to these mafic lavas as the Southern Cordilleran Basaltic Andesite (SCORBA) suite, and they may constitute the most extensive Cenozoic basaltic suite in North America. The SCORBA suite has trace element and isotopic characteristics of orogenic (arc) rocks (e.g., Ba/Nb>40), and silica content (53-56% SiO2) like the Grande Ronde Basalt, which represents about 80% of the volume of the Columbia River Group. Geochemical and isotopic data are presented on SCORBA lavas and rare mafic lavas (PRE-SCORBA) interlayered with older ignimbrites from a 700-km-long NE-SW transect of southern Chihuahua, Mexico. SCORBA and PRE-SCORBA lavas with relatively low K/P (<7) and differing Ba/Nb (50 versus 18) have similar isotopic compositions, arguing against their isotopic signatures being controlled by crustal assimilation. Along the entire length of the transect, the basaltic rocks have ɛNd and 87Sr/86Sr near bulk Earth and 206Pb/204Pb and 207Pb/204Pb ratios that lie along a 1.7 Ga pseudoisochron. The Pb isotopic variation is geographically controlled, becoming more radiogenic from east to west, reflecting mixing in mantle source regions. The eastern mantle source has low 206Pb/204Pb and is a mixture of an enriched, enriched-mantle-like (EMI) component with one or more depleted components, which could include an intraplate component with relatively high Nb/Y (>0.8). The western mantle source contains less of the intraplate component and is more oceanic in character. Overprinting both the eastern and western sources is a Cenozoic subduction component that is responsible for the western radiogenic Pb, and this component fades out inland to the east. This transect crosses the inferred position of the Mojave-Sonora megashear, previously proposed to be a major lithospheric boundary, separating Proterozoic basement to

  19. Unraveling the complex local-scale flows influencing ozone patterns in the southern Great Lakes of North America

    NASA Astrophysics Data System (ADS)

    Levy, I.; Makar, P. A.; Sills, D.; Zhang, J.; Hayden, K. L.; Mihele, C.; Narayan, J.; Moran, M. D.; Sjostedt, S.; Brook, J.

    2010-11-01

    This study examines the complexity of various processes influencing summertime ozone levels in the southern Great Lakes region of North America. Results from the Border Air Quality and Meteorology (BAQS-Met) field campaign in the summer of 2007 are examined with respect to land-lake differences and local meteorology using a large array of ground-based measurements, aircraft data, and simulation results from a high resolution (2.5 km) regional air-quality model, AURAMS. Analyses of average ozone mixing ratio from the entire BAQS-Met intensive campaign period support previous findings that ozone levels are higher over the southern Great Lakes than over the adjacent land. However, there is great heterogeneity in the spatial distribution of surface ozone over the lakes, particularly over Lake Erie during the day, with higher levels located over the southwestern end of the lake. Model results suggest that some of these increased ozone levels are due to local emission sources in large nearby urban centers. While an ozone reservoir layer is predicted by the AURAMS model over Lake Erie at night, the land-lake differences in ozone mixing ratios are most pronounced during the night in a shallow inversion layer of about 200 m above the surface. After sunrise, these differences have a limited effect on the total mass of ozone over the lakes and land during the day, though they do cause elevated ozone levels in the lake-breeze air in some locations. The model also predicts a mean vertical circulation during the day with an updraft over Detroit-Windsor and downdraft over Lake St. Clair, which transports ozone up to 1500 m above ground and results in high ozone over the lake. Oscillations in ground-level ozone mixing ratios were observed on several nights and at several ground monitoring sites, with amplitudes of up to 40 ppbv and time periods of 15-40 min. Several possible mechanisms for these oscillations are discussed, but a complete understanding of their causes is not

  20. Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy)

    NASA Astrophysics Data System (ADS)

    De Vita, P.; Allocca, V.; Manna, F.; Fabbrocino, S.

    2012-05-01

    Thus far, studies on climate change have focused mainly on the variability of the atmospheric and surface components of the hydrologic cycle, investigating the impact of this variability on the environment, especially with respect to the risks of desertification, droughts and floods. Conversely, the impacts of climate change on the recharge of aquifers and on the variability of groundwater flow have been less investigated, especially in Mediterranean karst areas whose water supply systems depend heavily upon groundwater exploitation. In this paper, long-term climatic variability and its influence on groundwater recharge were analysed by examining decadal patterns of precipitation, air temperature and spring discharges in the Campania region (southern Italy), coupled with the North Atlantic Oscillation (NAO). The time series of precipitation and air temperature were gathered over 90 yr, from 1921 to 2010, using 18 rain gauges and 9 air temperature stations with the most continuous functioning. The time series of the winter NAO index and of the discharges of 3 karst springs, selected from those feeding the major aqueducts systems, were collected for the same period. Regional normalised indexes of the precipitation, air temperature and karst spring discharges were calculated, and different methods were applied to analyse the related time series, including long-term trend analysis using smoothing numerical techniques, cross-correlation and Fourier analysis. The investigation of the normalised indexes highlighted the existence of long-term complex periodicities, from 2 to more than 30 yr, with differences in average values of up to approximately ±30% for precipitation and karst spring discharges, which were both strongly correlated with the winter NAO index. Although the effects of the North Atlantic Oscillation (NAO) had already been demonstrated in the long-term precipitation and streamflow patterns of different European countries and Mediterranean areas, the results

  1. Geology, mineralization, and geochronology of the Qianhe gold deposit, Xiong'ershan area, southern North China Craton

    NASA Astrophysics Data System (ADS)

    Tang, Ke-Fei; Li, Jian-Wei; Selby, David; Zhou, Mei-Fu; Bi, Shi-Jian; Deng, Xiao-Dong

    2013-08-01

    The Qianhe gold deposit in the Xiong'ershan area is located along the southern margin of the Archean-Paleoproterozoic North China Craton. The deposit consists of six orebodies that are hosted in Paleoproterozoic andesites to basaltic andesites and structurally controlled by roughly EW-trending faults. Individual orebodies comprise auriferous quartz veins and disseminated Au-bearing pyrite within hydrothermally altered rocks on both sides of, or close to, the veins. Ore-related hydrothermal alteration has produced various mixtures of K-feldspar, quartz, sericite, chlorite, epidote, carbonate, and sulfides. Pyrite is the most important ore mineral, associated with minor amounts of galena, sphalerite, and chalcopyrite. Other trace minerals include molybdenite, arsenopyrite, scheelite, rutile, xenotime, and parisite. Gold occurs mostly as native gold and electrum enclosed in pyrite or along microfractures of sulfides and quartz. Microthermometric measurements of primary inclusions in auriferous quartz suggest that gold and associated minerals were precipitated in the range of 160-305 °C from aqueous or carbonic-aqueous fluids with salinities of 6-22 wt% NaCl equiv. Samples of molybdenite coexisting with Au-bearing pyrite have Re-Os model ages of 134-135 Ma, whereas ore-related hydrothermal sericite separates yield 40Ar/39Ar plateau ages between 127 and 124 Ma. The Re-Os and 40Ar/39Ar ages are remarkably consistent with zircon U-Pb ages (134.5 ± 1.5 and 127.2 ± 1.4 Ma; 1 σ) of the biotite monzogranite from the Heyu-intrusive complex and granitic dikes in and close to the Qianhe gold mine, indicating a close temporal and thus possibly genetic relationship between gold mineralization and granitic magmatism in the area. Fluid inclusion waters extracted from auriferous quartz have δD values of -80 to -72 ‰, whereas the calculated δ 18OH2O values range from 3.1 to 3.8 ‰. The hydrogen and oxygen isotopes from this study and previous work indicate that ore fluids

  2. Palm leaves from the Late Oligocene sediments of Makum Coalfield, Assam, India

    NASA Astrophysics Data System (ADS)

    Srivastava, Gaurav; Mehrotra, R. C.; Bauer, Hugues

    2012-06-01

    Two new palm leaf impressions, cf. Iguanura wallichiana and Palmacites makumensis sp. nov. are described from the Makum Coalfield, Tinsukia District, Assam. They belong to the Tikak Parbat Formation being considered as Late Oligocene (Chattian 28-23 Myr) in age. Their presence, along with the other known fossil records indicates that CMMT (cold month mean temperature) was not less than 18°C with plenty of rainfall, in the region during the period of deposition.

  3. Potential field modelling of palaeozoic sediments, intrusions and orogenic structures in the southern part of the Danish North Sea.

    NASA Astrophysics Data System (ADS)

    Lyngsie, S. B.; Thybo, H.

    2003-04-01

    Palaeozoic sediments cover the entire Danish area and vary considerably in depth and thickness (less than 0.5 s twt on the 'Kattegat Skagerak Platform' to more than 1.5 s twt on the 'Ringkøbing Fyn High' (RFH), and up to 2-3 s twt in the deep basins). The Palaeozoic interval and orogenic structures of the crystalline crust are modelled by integrating reflection seismic data and potential field data in the southern part of the Danish Central Graben (CG) Area and the RFH. Using a variety of transformation and imaging methods the potential field data from the North Sea are analysed for shallow and deep-seated orogenic structures. By integrating a depth-converted section of the MONA LISA 3 profile with potential field data extracted along the profile, excellent control on the gravity and magnetic modelling is obtained with 2 1/2 D modelling using the program GM-SYS. The modelled profile indicates a strongly block faulted RFH covered by a thick (> 3 km) Palaeozoic sequence and vertical and horizontal intrusions beneath the CG and in the crystalline crust of the RFH. A 3D modelling method is used to calculate the gravity effects of seawater and all sediments of post Early Permian age in the CG area and the RFH area. The residual gravity image clearly supports the results of the modelled profile by revealing evidence of intrusions in the crust beneath CG and the RFH. Velocity modelling based on wide-angle refraction data, supports the indication of the presence of down faulted Palaeozoic sediments. Correlation of several deep seismic reflection profiles indicates internal orogenic crustal structures, probably of pre-Caledonian age, in areas adjacent to RFH.

  4. Influences of the El Nino Southern Oscillation and the Pacific Decadal Oscillation on the Timing of the North American Spring

    NASA Technical Reports Server (NTRS)

    McCabe, Gregory J.; Ault, Toby R.; Cook, Benjamin I.; Betancourt, Julio L.; Schwartz, Mark D.

    2012-01-01

    Detrended, modelled first leaf dates for 856 sites across North America for the period 1900-2008 are used to examine how the El Nino Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) separately and together might influence the timing of spring. Although spring (mean March through April) ENSO and PDO signals are apparent in first leaf dates, the signals are not statistically significant (at a 95% confidence level (p <0.05)) for most sites. The most significant ENSO/PDO signal in first leaf dates occurs for El Nino and positive PDO conditions. An analysis of the spatial distributions of first leaf dates for separate and combined ENSO/PDO conditions features a northwest-southeast dipole that is significantly (at p <0.05) different than the distributions for neutral conditions. The nature of the teleconnection between Pacific SST's and first leaf dates is evident in comparable composites for detrended sea level pressure (SLP) in the spring months. During positive ENSO/PDO, there is an anomalous flow of warm air from the southwestern US into the northwestern US and an anomalous northeasterly flow of cold air from polar regions into the eastern and southeastern US. These flow patterns are reversed during negative ENSO/PDO. Although the magnitudes of first leaf date departures are not necessarily significantly related to ENSO and PDO, the spatial patterns of departures are significantly related to ENSO and PDO. These significant relations and the long-lived persistence of SSTs provide a potential tool for forecasting the tendencies for first leaf dates to be early or late.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  6. Tidal cycles of total particulate mercury in the Jade Bay, lower Saxonian Wadden Sea, southern North Sea.

    PubMed

    Jin, Huafang; Liebezeit, Gerd

    2013-01-01

    In this study, we evaluate the nature of the relationship between particulate matter and total mercury concentrations. For this purpose, we estimate both of the two values in water column over 12-h tidal cycles of the Jade Bay, southern North Sea. Total particulate mercury in 250 mL water samples was determined by oxygen combustion-gold amalgamation. Mercury contents varied from 63 to 259 ng/g suspended particulate matter (SPM) or 3.5-52.8 ng/L in surface waters. Total particulate mercury content (THg(p)) was positively correlated with (SPM), indicating that mercury in tidal waters is mostly associated with (SPM), and that tidal variations of total particulate mercury are mainly due to changes in (SPM) content throughout the tidal cycle. Maximum values for THg(p) were observed during mid-flood and mid-ebb, while the lowest values were determined at low tide and high tide. These data suggest that there are no mercury point sources in the Jade Bay. Moreover, the THg(p) content at low tide and high tide were significantly lower than the values recorded in the bottom sediment of the sampling site (>200 ng/g DW), while THg(p) content during the mid-flood and mid-ebb were comparable to the THg content in the surface bottom sediments. Therefore, changes in THg(p) content in the water column due to tidal forcing may have resulted from re-suspension of underlying surface sediments with relatively high mercury content.

  7. The genesis of early Carboniferous adakitic rocks at the southern margin of the Alxa Block, North China

    NASA Astrophysics Data System (ADS)

    Xue, Shuo; Ling, Ming-Xing; Liu, Yu-Long; Zhang, Hong; Sun, Weidong

    2017-05-01

    Adakite is a highly debated petrologic term that was originally proposed to describe igneous rocks formed by slab melting. Subsequent studies reported other ways to generate adakitic signatures such as the melting of mafic lower continental crust and fractional crystallization of basaltic magma. We studied adakitic rocks from the Taohuala Mountain at the southern margin of the Alxa Block, North China. These rocks are characterized by high Sr concentrations (300-450 ppm), high Sr/Y (20-75 ppm) and (La/Yb)N (25-67 ppm) ratios, and low Y (< 18 ppm) and Yb (< 1.9 ppm) concentrations, which are typical of adakite. The distribution of these data on a Sr/Y versus (La/Yb)N discrimination diagram, combined with their high (87Sr/86Sr)i ratios (0.7113-0.7131) and low εNd(t) (- 15.8 to - 16.8) and εHf(t) (- 18 to - 10) values of zircon, indicates that the adakitic rocks formed by partial melting of thickened continental crust. U-Pb dating of zircons using LA-ICP-MS yields an early Carboniferous age of 330 ± 5 Ma. The ages and spatial distribution of magmatic rocks indicate that the Paleo-Asian oceanic crust subducted towards the Alxa Block in the late Paleozoic. Subsequently, northward slab rollback occurred during the Carboniferous. Therefore, we propose that the adakitic rocks from the Taohuala Mountain formed by partial melting of previously thickened lower continental crust, induced by the upwelling of asthenospheric mantle during slab rollback.

  8. The Dimethylsulfide Cycle in the Eutrophied Southern North Sea: A Model Study Integrating Phytoplankton and Bacterial Processes

    PubMed Central

    Gypens, Nathalie; Borges, Alberto V.; Speeckaert, Gaelle; Lancelot, Christiane

    2014-01-01

    We developed a module describing the dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) dynamics, including biological transformations by phytoplankton and bacteria, and physico-chemical processes (including DMS air-sea exchange). This module was integrated in the MIRO ecological model and applied in a 0D frame in the Southern North Sea (SNS). The DMS(P) module is built on parameterizations derived from available knowledge on DMS(P) sources, transformations and sinks, and provides an explicit representation of bacterial activity in contrast to most of existing models that only include phytoplankton process (and abiotic transformations). The model is tested in a highly productive coastal ecosystem (the Belgian coastal zone, BCZ) dominated by diatoms and the Haptophyceae Phaeocystis, respectively low and high DMSP producers. On an annual basis, the particulate DMSP (DMSPp) production simulated in 1989 is mainly related to Phaeocystis colonies (78%) rather than diatoms (13%) and nanoflagellates (9%). Accordingly, sensitivity analysis shows that the model responds more to changes in the sulfur:carbon (S:C) quota and lyase yield of Phaeocystis. DMS originates equally from phytoplankton and bacterial DMSP-lyase activity and only 3% of the DMS is emitted to the atmosphere. Model analysis demonstrates the sensitivity of DMS emission towards the atmosphere to the description and parameterization of biological processes emphasizing the need of adequately representing in models both phytoplankton and bacterial processes affecting DMS(P) dynamics. This is particularly important in eutrophied coastal environments such as the SNS dominated by high non-diatom blooms and where empirical models developed from data-sets biased towards open ocean conditions do not satisfactorily predict the timing and amplitude of the DMS seasonal cycle. In order to predict future feedbacks of DMS emissions on climate, it is needed to account for hotspots of DMS emissions from coastal

  9. The dimethylsulfide cycle in the eutrophied Southern North Sea: a model study integrating phytoplankton and bacterial processes

    NASA Astrophysics Data System (ADS)

    Gypens, Nathalie; Borges, Alberto V.; Speeckaert, Gaelle; Lancelot, Christiane

    2014-05-01

    We developed a module describing the dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) dynamics, including biological transformations by phytoplankton and bacteria, and physico-chemical processes (including DMS air-sea exchange). This module was integrated in the MIRO ecological model and applied in a 0D frame in the Southern North Sea (SNS). The DMS(P) module is built on parameterizations derived from available knowledge on DMS(P) sources, transformations and sinks, and provides an explicit representation of bacterial activity in contrast to most of existing models that only include phytoplankton process (and abiotic transformations). The model is tested in a highly productive coastal ecosystem (the Belgian coastal zone, BCZ) dominated by diatoms and the Haptophyceae Phaeocystis, respectively low and high DMSP producers. On an annual basis, the particulate DMSP (DMSPp) production simulated in 1989 is mainly related to Phaeocystis colonies (78%) rather than diatoms (13%) and nanoflagellates (9%). Accordingly, sensitivity analysis shows that the model responds more to changes in the sulfur:carbon (S:C) quota and lyase yield of Phaeocystis. DMS originates equally from phytoplankton and bacterial DMSP-lyase activity and only 3% of the DMS is emitted to the atmosphere. Model analysis demonstrates the sensitivity of DMS emission towards the atmosphere to the description and parameterization of biological processes emphasizing the need of adequately representing in models both phytoplankton and bacterial processes affecting DMS(P) dynamics. This is particularly important in eutrophied coastal environments such as the SNS dominated by high non-diatom blooms and where empirical models developed from data-sets biased towards open ocean conditions do not satisfactorily predict the timing and amplitude of the DMS seasonal cycle. In order to predict future feedbacks of DMS emissions on climate, it is needed to account for hotspots of DMS emissions from coastal

  10. Centennial-scale vegetation and North Atlantic Oscillation changes during the Late Holocene in the southern Iberia

    NASA Astrophysics Data System (ADS)

    Ramos-Román, M. J.; Jiménez-Moreno, G.; Anderson, R. S.; García-Alix, A.; Toney, J. L.; Jiménez-Espejo, F. J.; Carrión, J. S.

    2016-07-01

    High-reso CE to lution pollen analysis, charcoal, non-pollen palynomorphs and magnetic susceptibility have been analyzed in the sediment record of a peat bog in Sierra Nevada in southern Iberia. The study of these proxies provided the reconstruction of vegetation, climate, fire and human activity of the last ∼4500 cal yr BP. A progressive trend towards aridification during the late Holocene is observed in this record. This trend is interrupted by millennial- and centennial-scale variability of relatively more humid and arid periods. Arid conditions are recorded between ∼4000 and 3100 cal yr BP, being characterized by a decline in arboreal pollen and with a spike in magnetic susceptibility. This is followed by a relatively humid period from ∼3100 to 1600 cal yr BP, coinciding partially with the Iberian-Roman Humid Period, and is indicated by the increase of Pinus and the decrease in xerophytic taxa. The last 1500 cal yr BP are characterized by several centennial-scale climatic oscillations. Generally arid conditions from ∼450 to 1300 CE, depicted by a decrease in Pinus and an increase in Artemisia, comprise the Dark Ages and the Medieval Climate Anomaly. Since ∼ 1300 to 1850 CE pronounced oscillations occur between relatively humid and arid conditions. Four periods depicted by relatively higher Pinus coinciding with the beginning and end of the Little Ice Age are interrupted by three arid events characterized by an increase in Artemisia. These alternating arid and humid shifts could be explained by centennial-scale changes in the North Atlantic Oscillation and solar activity.

  11. Reservoir leakage along concentric faults in the Southern North Sea: Implications for the deployment of CCS and EOR techniques

    NASA Astrophysics Data System (ADS)

    Ward, Nicholas I. P.; Alves, Tiago M.; Blenkinsop, Tom G.

    2016-10-01

    High-quality 3D seismic and borehole data in the Broad Fourteens Basin, Southern North Sea, is used to investigate newly recognised concentric faults formed in salt-withdrawal basins flanking reactivated salt structures. Throw-depth and throw-distance plots were used to understand the growth histories of individual faults. As a result, three families of concentric faults are identified: a) intra-seal faults within a salt-withdrawal basin, b) faults connecting the seal and the reservoir on the crest of an inverted anticline, c) raft-bounding faults propagating into reservoir units. They have moved obliquely and show normal throws, even though they formed during a period of regional compression. Faults in the salt-withdrawal basin and on the inverted anticline are highly segmented, increasing the chances of compartmentalisation or localised fluid flow through fault linkages. Slip tendency analysis was carried out on the distinct fault families to compare the likelihood of slip along a fault at different pore fluid pressures and within different lithologies. Our results show that sections of the faults are optimally oriented with regards to maximum horizontal stresses (σHmax), increasing the slip tendency. The identified faults cut through a variety of lithologies, allowing different values of pore fluid pressures to build up before faults reactivate. Within the Vlieland Sandstones, pore fluid pressures of 30 MPa are not sufficient to reactivate pre-existing faults, whereas in the deeper Posidonia Shales faults might reactivate at pore fluid pressures of 25 MPa. Fluid flow features preferentially occur near fault segments close to failure. Heterogeneity in slip tendency along concentric faults, and high degrees of fault segmentation, present serious hazards when injecting CO2 into the subsurface. This study stresses the importance of high-quality 3D seismic data and the need to evaluate individual fault systems when investigating potential reservoirs for carbon

  12. Assessing the effect of nutrient mitigation measures in the watersheds of the Southern Bight of the North Sea.

    PubMed

    Thieu, Vincent; Garnier, Josette; Billen, Gilles

    2010-02-15

    The Seine, Somme, and Scheldt Rivers (France, Belgium, and Netherlands) are the major delivering rivers flowing into the continental coastal zone of the Southern Bight of the North Sea, an area regularly affected by eutrophication problems. In the present work, the Seneque-Riverstrahler model was implemented in a multi-regional case study in order to test several planned mitigation measures aimed at limiting stream nutrient contamination and restoring balanced nutrient ratios at the coastal zone. This modeling approach, which is spatially distributed at the basin scale, allows assessing the impact of any change in human activities, which widely differ over the three basins. Here, we define realistic scenarios based on currently proposed measures to reduce point and non-point sources, such as the upgrading of wastewater treatment, the introduction of catch crops, and the development of extensive farming. An analysis of the current situation showed that a 47-72% reduction in P point-source emissions within the three basins could be reached if the intended P treatment was generalized to the largest treatment plants. However, only an overall 14-23% reduction in N could be achieved at the outlet of the three basins, by combining improved wastewater treatment and land use with management measures aimed at regulating agricultural practices. Nonetheless, in spite of these efforts, N will still be exported in large excess with respect to the equilibrium defined by the Redfield ratios, even in the most optimistic hypothesis describing the long-term response of groundwater nitrate concentrations. A comprehensive assessment of these mitigation measures supports the need for additional reductions of nutrient losses from agriculture to control harmful algae development. It also stresses the relevance of this mechanistic approach, in which nutrient transfers from land to sea can be calculated, as an integrated strategy to test policy recommendations.

  13. Three-dimensional modelling of the hydrodynamics of the Southern Bight of the North Sea: first results

    NASA Astrophysics Data System (ADS)

    Ivanov, Evgeny; Capet, Arthur; Barth, Alexander; Delhez, Eric; Soetaert, Karline; Grégoire, Marilaure

    2017-04-01

    In the frame of the Belgian research project FaCE-It (Functional biodiversity in a Changing sedimentary Environment: Implications for biogeochemistry and food webs in a managerial setting), the impact of dredging activities and offshore wind farm installation on the spatial distribution of sediment grain size, biodiversity and biogeochemistry will be estimated in the Southern Bight of the North Sea (SBNS) with a focus on the Belgian Coastal Zone (BCZ). To reach this goal, the three-dimensional hydrodynamical model ROMS-COAWST is implemented in the SBNS in order to simulate the complex hydrodynamics and sediment transport. Two levels of nesting are used to reach a resolution of 250 m in the BCZ. The model is forced at the air-sea interface by the 6-hourly ECMWF ERA-interim atmospheric dataset and at the open boundaries by the coarse resolution model results available from CMEMS (Copernicus Marine Environment Monitoring Service), and also considers tides and 4 main rivers (Scheldt, Rhine with Maas, Thames and Seine). Two types of simulations have been performed: a 10-years climatological simulation and a simulation over 2003-2013 to investigate the interannual dynamics. The model skills are evaluated by comparing its outputs to historical data (e.g. salinity, temperature and currents) from remote sensing and in-situ. The sediment transport module will then be implemented and its outputs compared to historical and newly collected (in the frame of FaCE-iT) observations on grain size distribution as well as with satellite Suspended Particulate Matter (SPM) images. This will allow assessing the impact of substrate modification due to offshore human activities at local and regional scales.

  14. Composition and quality of coals in the Huaibei Coalfield, Anhui, China

    USGS Publications Warehouse

    Zheng, Lingyun; Liu, Gaisheng; Wang, L.; Chou, C.-L.

    2008-01-01

    The Huaibei Coalfield, Anhui Province, China, is one of the largest coalfields in China. The coals of Permian age are used mainly for power generation. Coal compositions and 47 trace elements of the No. 10 Coal of the Shanxi Formation, the No. 7, 5, and 4 Coals of the Lower Shihezi Formation, and the No. 3 Coal of the Upper Shihezi Formation from the Huaibei Coalfield were studied. The results indicate that the Huaibei coals have low ash, moisture, and sulfur contents, but high volatile matter and calorific value. The ash yield increases stratigraphically upwards, but the volatile matter and total sulfur contents show a slight decrease from the lower to upper seams. Magmatic intrusion into the No. 5 Coal resulted in high ash, volatile matter, and calorific value, but low moisture value in the coal. Among the studied 47 trace elements, Ba, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Th, U, V, and Zn are of environmental concerns. Four elements Hg, Mo, Zn, and Sb are clearly enriched in the coals as compared with the upper continental crust. ?? 2007 Elsevier B.V. All rights reserved.

  15. Characterization and preparation of Dipka coal from Korba coalfield in India

    SciTech Connect

    Gollakota, S.; Rao, N.; Duerbrouck, A.; Staats, G.

    1998-12-31

    The Korba coalfield is one of the most important non-coking coalfields in India because of large reserves and high annual production. The Dipka coal, from Korba coalfield, will be cleaned in the first private, non-coking coal washery being constructed in Bilaspur, India, as a joint venture of U.S. and Indian companies. The US Agency for International Development (USAID) has assisted these companies in an effort to demonstrate advanced coal beneficiation methods at this washery. Because of increasing dependence on coal-based power generation in India, coal production and preparation play an important role in this country`s economy and environmental management. USAID, through US Department of Energy, is providing the necessary technical support in activities related to coal preparation in India. An overview of these activities will be presented. An analysis of the Dipka coal was performed with emphasis on a large sample recently collected. The effects of raw coal variability and crushing on washability characteristics and energy recovery in coal preparation were studied. This study was conducted at the Federal Energy Technology Center (FETC) in Pittsburgh. Based on an analysis conducted and flowsheets developed at FETC, the Dipka coal was cleaned at the Central Fuel Research Institute`s pilot-plant in Dhanbad (India). The economic benefits of Dipka coal cleaning for power generation and the status of Bilaspur Washery construction and operation will be highlighted.

  16. Long-term impact of bottom trawling on pelagic-benthic coupling in the southern North Sea (German Bight)

    NASA Astrophysics Data System (ADS)

    Friedrich, Jana; van Beusekom, Justus E. E.; Neumann, Andreas; Naderipour, Celine; Janssen, Felix; Ahmerkamp, Soeren; Holtappels, Moritz; Schueckel, Ulrike

    2016-04-01

    The southern North Sea, and the German Bight, has been systematically bottom-trawled at least since the late 19th century (Christiansen, 2009; Reiss et al., 2009; Kröncke 2011; Emeis et al., 2015, Neumann et al., 2016). As a result, benthic habitats and benthic biogenic structures created by bivalves, polychaetes and hydroids where destroyed or reduced. The parallel removal of hard substrate (gravel and boulders) avoids the resettlement of hard-substrate depended species. For example, the Oyster ground, a huge oyster bank a hundred years ago (Olsen, 1883), turned into a muddy depression today. In addition, shallow depth of max 40 m, strong tidal currents and frequent storms result in a high-energy environment with low sedimentation rates and recurrent sediment resuspension. The decrease in benthic filtering capacity by disturbance in epifauna and bottom roughness (Callaway et al., 2007) apparently influence pelagic-benthic coupling of biogeochemical fluxes. Heip et al. (1995) indicate that benthic respiration at depths prevailing in the German Bight accounts for 10-40% of total respiration, whereas pelagic respiration accounts for 60-90%. Previous estimates are in the middle of this range (Heip et al., 1995). To test these hypotheses and to assess the partitioning of benthic and pelagic processes, and the factors influencing organic matter mineralization, we measured pelagic production and respiration based on Winkler titration, in-situ benthic fluxes using chamber landers, we did ex-situ incubations of intact sediment cores and analysed still images from a towed benthic video sled. In addition, O2 fluxes in permeable sediments were estimated by integrating the volumetric rate measurements of the upper sediment layer over in-situ microsensor-measured O2 penetration depth. Our current results show significant seasonality in benthic respiration, with highest rates in summer and lowest rates in winter. No significant differences in total benthic respiration rates

  17. Millennial scale precipitation changes over Easter Island (Southern Pacific) during MIS 3: Inter-hemispheric connections during North Atlantic abrupt cold events

    NASA Astrophysics Data System (ADS)

    Margalef, Olga; Cacho, Isabel; Pla-Rabes, Sergi; Cañellas-Boltà, Núria; Pueyo, Juan Jose; Sáez, Alberto; Valero-Garcés, Blas L.; Giralt, Santiago

    2013-04-01

    Marine Isotope Stage (MIS) 3 climate has been globally characterized by the occurrence of millennial-scale climate variations defined over North Atlantic as Dansgaard-Oeschger and Heinrich events. Despite climate variability has been broadly explored over North Atlantic records, the response of the tropical and subtropical latitudes, especially in the Southern Hemisphere, still remains as a matter of debate. Rano Aroi peat record (Easter Island, Chile, 27°S) provides a unique opportunity to understand Southern Pacific atmospheric and oceanic changes during these stadial-interstadial transitions because of its exceptional location on the interplay of the South Pacific Convergence Zone (SPCZ), the Intertropical Convergence Zone (ITCZ), the South Pacific Anticyclone (SPA) and the Southern Westerlies (SW). Rano Aroi record contains 8 main enhanced precipitation events between 70 and 40 kyr BP that can be correlated with the timing of Heinrich events 5, 5a and 6 as well as other cold stadials. These humid events are also present in other Southern Hemisphere continental sites and correspond to dry periods on Northern Hemisphere records. This opposite hydrologic trend has been explained by the latitudinal migration of ITCZ and has been supported by several climatic models. As Easter Island precipitation is mainly dependent on SPCZ storm track belt activity, we suggest that the southern migration of the ITCZ is associated to an expansion of SPCZ to the east. This process should be intimately related to a weakening of the Walker circulation, which is further supported by an estimation of d18Osw gradient along the equator for the same time period. Consequently, atmospheric and oceanic responses during these cold stadials and Heinrich events might lead to a configuration that resembles the warm ENSO state over Southern Pacific, as previously suggested by some global climatic models. Rano Aroi record clearly points out that shifts in hydrological cycle in tropical Southern

  18. Lithospheric delamination in post-collisional setting: Evidence from intrusive magmatism from the North Qilian orogen to southern margin of the Alxa block, NW China

    NASA Astrophysics Data System (ADS)

    Zhang, Liqi; Zhang, Hongfei; Zhang, Shasha; Xiong, Ziliang; Luo, Biji; Yang, He; Pan, Fabin; Zhou, Xiaochun; Xu, Wangchun; Guo, Liang

    2017-09-01

    Post-collisional granitoids are widespread in the North Qilian and southern margin of the Alxa block and their petrogenesis can provide important insights into the lithospheric processes in a post-collisional setting. This paper carries out an integrated study of U-Pb zircon dating, geochemical and Sr-Nd-Hf isotopic compositions for five early Paleozoic intrusive plutons from the North Qilian to southern margin of the Alxa block. The geochronological and geochemical results show that their magmatism can be divided into three periods with distinct geochemical features. The early-period intrusive rocks ( 440 Ma) include the Lianhuashan (LHS) and Mengjiadawan (MJDW) granodiorites. Both of them display high Sr/Y ratios (52-91), coupled with low Y and HREE contents, implying that they were derived from partial melting of thickened lower crust, with garnet in the residue. The middle-period intrusive rocks ( 430 Ma), including the MJDW quartz diorites and Yangqiandashan (YQDS) granodiorites, are high-K calc-alkaline with low Sr/Y values. The geochemical and isotopic data suggest that they are generated from partial melting of lower crust without garnet in the residue. The late-period intrusive rocks (414-422 Ma), represented by the Shengrongsi (SRS) and Xinkaigou (XKG) plutons, are A-type or alkali-feldspar granites. They are possibly derived from partial melting of felsic crustal material under lower pressure condition. Our data show decreasing magma crystallization ages from MJDW pluton in the north and LHS pluton in the south to the SRS and XKG plutons in the central part of the study area. We suggest that such spatial and temporal variations of magmatic suites were caused by lithospheric delamination after the collision between the Central Qilian and the Alxa block. A more plausible explanation is that the delamination propagated from the margin part of the thickened lithosphere to inward beneath the North Qilian and southern margin of the Alxa block.

  19. The influence of eastern North American autumnal migrant monarch butterflies (Danaus plexippus L.) on continuously breeding resident monarch populations in southern Florida.

    PubMed

    Knight, Amy; Brower, Lincoln P

    2009-07-01

    In Florida, the eastern North American population of the monarch butterfly exhibits geographic variability in population structure and dynamics. This includes the occurrence of migrants throughout the peninsula during the autumnal migration, occasional overwintering clusters that form along the Gulf Coast, remigrants from Mexico that breed in north-central Florida during the spring, and what have been assumed to be year-round, resident breeding populations in southern Florida. The work reported here focused on two monarch populations west of Miami and addressed four questions: Are there permanent resident populations of monarchs in southern Florida? Do these breed continuously throughout the year? Do they receive northern monarchs moving south during the autumn migration? Do they receive overwintered monarchs returning via Cuba or the Yucatan during the spring remigration from the Mexican overwintering area? Monthly collections and counts of spermatophores in the bursa copulatrices of females established that a resident population of continuously breeding monarchs exists year-round in southern Florida. It was determined through cardenolide fingerprinting that most of the butterflies had bred on the local southern Florida milkweed species, Asclepias curassavica. During the autumn migration period, however, some monarchs had fed on the northern milkweed, Asclepias syriaca. It appears that instead of migrating to Mexico, these individuals travel south through peninsular Florida, break diapause, mate with and become incorporated into the resident breeding populations. None of the monarchs captured in spring had the A. syriaca cardenolide fingerprint, which is evidence against the southern Florida populations receiving overwintered remigrants from Cuba, Central America or Mexico.

  20. A new high-resolution kinematic model for the southern North Atlantic region: the Iberian plate kinematics since the Late Cretaceous

    NASA Astrophysics Data System (ADS)

    Macchiavelli, Chiara; Vergés, Jaume; Schettino, Antonio; Fernández, Manel; Turco, Eugenio; Torné, Montserrat; Casciello, Emilio

    2017-04-01

    We present the first high-resolution kinematic model for the southern North Atlantic since the late Cretaceous, in order to constrain the Iberian kinematics during the last 83 Myr. Assessing the detailed movements of the Iberian plate is crucial to constrain the kinematics of the Western Mediterranean region and to better understand the Pyrenees and Betic - Rif orogenic systems evolution. The new plate motions model for the Iberia - North America plate pair is accompanied by a high-resolution isochron map for the southern North Atlantic region, resulting from a re-examination of 400 ship tracks and 3 aeromagnetic tracks in the NGDC data base for the area between the Azores triple junction and 46° N. We derive a well-constrained kinematic solution for the relative motion between an independent Iberia and North America from seafloor spreading data despite the short length of the magnetic lineations and the scarcity of large-offset transform faults and fracture zones. Accurate finite reconstruction poles for the Iberia - North America conjugate plate pair between the Late Cretaceous (Chron 34, 83.5 Ma) and the present day (Chron 2A, 2.58 Ma) are calculated on the basis of a set of 100 magnetic profiles through an iterative method. Euler poles and associated angles of rotation are computed as follow. An initial rotation pole is calculated using only magnetic anomaly crossings. The initial large uncertainty associated with the first determination is reduced by generating a set of synthetic fracture zones associated with the initial pole and using points sampled along these structures in conjunction with magnetic anomaly crossings to calculate a new Euler pole and associated confidence ellipse. This procedure is repeated n times, generating a sequence of improving approximate solutions and stopped when the solution become stable excluding solutions that were inconsistent with geological constraints. We used these results to build a comprehensive kinematic model for the

  1. West Point Melange, remnants of a Lower Paleozoic ophiolitic, eclogite-bearing melange in the Southern Appalachians, Alabama, Georgia, and North Carolina

    SciTech Connect

    Crawford, R.F. III; Higgins, M.W.; Crawford, T.

    1985-01-01

    The lower Paleozoic West Point melange in the West Point thrust sheet is locally preserved beneath and commonly folded with ocean-floor Ropes Creek Metabasalt of the Ropes Creek thrust sheet in the crystalline terrane of Alabama, Georgia, and North Carolina. The melange overlies a calc-alkaline island arc assemblage known as the Paulding volcanic-plutonic complex in the Paulding thrust sheet. The matrix of the melange is generally highly sheared talc-actinolite schist and (or) highly deformed amphibolite, and less commonly sheared scaly pelitic schist. Most clasts in the melange are of a wide variety of mafic and ultramafic rocks, including dunite, coronite troctolite, olivine gabbro, wehrlite, cortlandite, pyroxenite, and olivine-pyroxenite. Eclogite clasts are found at several localities in northern Georgia, southern North Carolina, and in Alabama. The mostly mafic ophiolitic nature of the West Point melange, the clasts of eclogite, and its location between an island-arc assemblage and ocean-ridge basalts suggests that it is the remnants of a subduction melange formed between the mid-Iapetus ridge and the oceanic Paulding island arc. The melange also forms part of the Hillabee Greenstone in Alabama and the Lake Chatuge sill and Shooting Creek complex in northern Georgia and southern North Carolina.

  2. Regional characteristics of stress field in the southern part of the north-south seismic belt in China and its relation with plate movement

    NASA Astrophysics Data System (ADS)

    Xu, Ji-Ren; Oike, Kazuo

    1995-02-01

    The regional characteristics of stress field in the southern part of the north-south seismic belt (NSB) have been analyzed in detail based on the mechanism solutions of 134 medium and large earthquakes from 1933 to 1991. The results show that the southern part of the NSB is a shallow earthquake zone where most earthquakes are caused by the strike-slip faulting. There is a systematic distribution of the directions of P- and T-axes in the western and the eastern regions of the southern part of the NSB. P- and T-axes in the western region are in the NE-SW direction and in the NW-SE direction. P- and T-axes in the eastern region are oriented in NW-SE and NE-SW, respectively. The directions of P-axes in the western and the eastern regions show a pattern of a reversal “V” as a whole. The boundary between the eastern and western regions coincides with that between the Tibetan Plateau and the Yangtze crustal block. Based on a lot of mechanism solutions, the result indicates that the direction of P-axes roughly shows the consistent distributions from the Himalayan collision zone to the eastern region and from the eastern coast collision zone in Taiwan to the eastern region of southern part of the NSB, respectively. It is suggested that the tectonic force due to relative movement between the Indo-Australian and the Eurasian plates is transmitted from the Himalayan collision zone to the western region of the southern part of NSB, simultaneously, the tectonic force due to the relative movement between the Philippine Sea and the Eurasian plates is transmitted from the eastern region coast in Taiwan to the eastern region of the southern part of NSB, and control the stress field there, respectively.

  3. A Regional View of the Margin: Salmonid Abundance and Distribution in the Southern Appalachian Mountains of North Carolina and Virginia

    Treesearch

    Patricia A. Flebbe

    1994-01-01

    In the southern Appalachian Mountains, native brook trout Salvelinus fontinalis and introduced rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta are at the southern extremes of their distributions, an often overlooked kind of marginal habitat. At a regional scale composed of the states of Virginia...

  4. Flame retardants in eggs of American kestrels and European starlings from southern Lake Ontario region (North America).

    PubMed

    Chen, Da; Letcher, Robert J; Martin, Pamela

    2012-11-01

    While a number of studies have extensively investigated flame retardant (FR) contamination in aquatic ecosystems from the Laurentian Great Lakes basin, there remains a dearth of information for terrestrial ecosystems. In the current study, American kestrels (Falco sparverius) (AMKE) and European starlings (Sturnus vulgaris) (EUST) that are terrestrial ecosystem consumers, and from the southern Lake Ontario regions, were investigated as potential terrestrial bio-monitoring species. Egg homogenates were screened for sixteen PBDE congeners and nineteen non-PBDE FRs of established or emerging environmental importance. PBDE congeners dominated the FR burdens in eggs of AMKE and EUST, with total concentrations ranging from 3.4 to 39.8 (median: 13.5) and 1.5 to 117 (median: 4.9) ng g(-1) wet weight (ww), respectively. Although the production and application of the Firemaster FF-1 (a commercial hexabromobiphenyl PBB mixture) has been discontinued for over four decades, its major component, 2,2',4,4',5,5'-hexabromobiphenyl (BB-153), was still frequently detected in AMKE and EUST eggs. Two isomers of the chlorinated FR Dechlorane plus (DP) were mostly detected in eggs collected from Niagara-on-the-Lake in the western portion of Lake Ontario, approximately 15 km from the only North American DP manufacturing site, clearly reflecting point source influences. FR comparisons in eggs from AMKE, EUST and Great Lakes herring gulls revealed species-specific contamination burdens and PBDE congener profiles, likely due to influences from trophic levels and PBDE congener-specific bioaccumulation and biomagnification capacities in terrestrial versus aquatic food chains. Insectivorous birds (e.g. great tit) and relatives of AMKE have also been used as bio-monitoring tools in European and Asian regions, allowing investigation of spatial distribution patterns on a more international scale. AMKE and EUST have also been used as model species for laboratory evaluation of FR toxic effects in

  5. Storms, shoreface morphodynamics, sand supply, and the accretion and erosion of coastal dune barriers in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Anthony, Edward J.

    2013-10-01

    The coast of the southern North Sea is bound by dune barriers that have developed adjacent to a shallow storm- and tide-dominated shoreface comprising numerous shore-parallel to sub-shore-parallel tidal sand banks. The banks evolve under the joint control of tide-, wave- and wind-induced shore-parallel currents, which tend to ‘stretch' them, eventually leading to bank division, and to shoaling and breaking storm waves, which tend to drive them ashore. The banks, thus, modulate the delivery of storm wave energy to the coast, redirect currents alongshore and are the sand sources for the accretion of coastal dunes. Foredune accretion occurs where major sand banks have migrated shoreward over the last centuries to be finally driven ashore and weld under the impact of storm waves. Morphological changes in the bank field can impact on shoreline stability through dissipation or enhanced shoreward transmission of storm wave energy and effects on radiation stress, particularly when waves are breaking over the banks. Where banks are close to the shore, mitigation of offshore sediment transport, especially during storms, can occur because of gradients in radiation stress generated by the complex 3D bank structure. These macro-scale mechanisms involve embedded meso-scale interactions that revolve around the mobility of sand waves, mobility of beach bars and troughs and foredune mobility, and micro-scale processes of bedform mobility in the subaqueous and intertidal domains, and of swash and aeolian beach-dune sand transport. These embedded interactions and the morphodynamic feedback loops illustrate the importance of synchroneity of sand transport from shoreface to dune on this coast. Large stretches of the foredunes show either signs of stability, or mild but chronic erosion. Furthermore, a demonstrated lack of a clear relationship occurs between storminess and coastal response over the second half of the 20th century. The present situation may be indicative of conditions

  6. Geochronology and Geochemistry of the Paleoproterozoic Yinyugou Group in the Southern North China Craton: Implications for Provenance and Tectonic Evolution

    NASA Astrophysics Data System (ADS)

    Sun, Q.

    2016-12-01

    Clastic rocks that experience low-grade metamorphism are widely used to understand the formation and evolution of the continental crust. The Paleoproterozoic Yinyugou Group in the southern North China Craton is a littoral facies clastic sedimentary sequence which is mainly composed of sandstones and mica schists. Most sandstones have lower Chemical Index of Alteration values than the schists, indicating that the sandstones experienced relatively weak chemical weathering process. The relatively mature material source of sandstones is evidenced by higher SiO2/Al2O3 value and lower Index of Compositional Variability values relative to the schists. Enrichment of LREE relative to HREE, flat HREE patterns and slightly negative Eu anomalies indicate the sedimentary sources are mainly composed of felsic rocks. Discrimination diagrams reveal that the Yinyugou Group received detritus dominantly from felsic sources with important contribution from mafic igneous rocks. U-Pb ages of detrital zircons can be divided into three groups: 2.65-2.40 Ga, 2.90-2.70 Ga and 3.50-3.20 Ga, with one predominant age peak at 2.50 Ga. A weighted average age of 2383±38 Ma calculated from the youngest detrital zircons bracket the maximum depositional age at 2380 Ma. Most 2.50 Ga zircons show sub-depleted mantle positive ɛHf(t) values and TDMC ages chiefly range from 3.10-2.70 Ga, representing the time of juvenile magmas extracted from depleted mantle. A small proportion of 2.50 Ga zircons give depleted mantle-like ɛHf(t) values with TDMC ages slightly older than their 207Pb/206Pb ages, suggesting growth of juvenile crust plus to the extensive reworking of mature crust at 2.5 Ga. The characteristics of dual sources and both passive margin and arc-related setting suggest that the Yinyugou Group were most likely deposited in a back-arc setting. Considering the previous studies, we propose that the NCC experienced a cycle of subduction-extension-subduction processes during Paleoproterozoic.

  7. Complementary Metaproteomic Approaches to Assess the Bacterioplankton Response toward a Phytoplankton Spring Bloom in the Southern North Sea.

    PubMed

    Wöhlbrand, Lars; Wemheuer, Bernd; Feenders, Christoph; Ruppersberg, Hanna S; Hinrichs, Christina; Blasius, Bernd; Daniel, Rolf; Rabus, Ralf

    2017-01-01

    Annually recurring phytoplankton spring blooms are characteristic of temperate coastal shelf seas. During these blooms, environmental conditions, including nutrient availability, differ considerably from non-bloom conditions, affecting the entire ecosystem including the bacterioplankton. Accordingly, the emerging ecological niches during bloom transition are occupied by different bacterial populations, with Roseobacter RCA cluster and SAR92 clade members exhibiting high metabolic activity during bloom events. In this study, the functional response of the ambient bacterial community toward a Phaeocystis globosa bloom in the southern North Sea was studied using metaproteomic approaches. In contrast to other metaproteomic studies of marine bacterial communities, this is the first study comparing two different cell lysis and protein preparation methods [using trifluoroethanol (TFE) and in-solution digest as well as bead beating and SDS-based solubilization and in-gel digest (BB GeLC)]. In addition, two different mass spectrometric techniques (ESI-iontrap MS and MALDI-TOF MS) were used for peptide analysis. A total of 585 different proteins were identified, 296 of which were only detected using the TFE and 191 by the BB GeLC method, demonstrating the complementarity of these sample preparation methods. Furthermore, 158 proteins of the TFE cell lysis samples were exclusively detected by ESI-iontrap MS while 105 were only detected using MALDI-TOF MS, underpinning the value of using two different ionization and mass analysis methods. Notably, 12% of the detected proteins represent predicted integral membrane proteins, including the difficult to detect rhodopsin, indicating a considerable coverage of membrane proteins by this approach. This comprehensive approach verified previous metaproteomic studies of marine bacterioplankton, e.g., detection of many transport-related proteins (17% of the detected proteins). In addition, new insights into e.g., carbon and nitrogen

  8. Complementary Metaproteomic Approaches to Assess the Bacterioplankton Response toward a Phytoplankton Spring Bloom in the Southern North Sea

    PubMed Central

    Wöhlbrand, Lars; Wemheuer, Bernd; Feenders, Christoph; Ruppersberg, Hanna S.; Hinrichs, Christina; Blasius, Bernd; Daniel, Rolf; Rabus, Ralf

    2017-01-01

    Annually recurring phytoplankton spring blooms are characteristic of temperate coastal shelf seas. During these blooms, environmental conditions, including nutrient availability, differ considerably from non-bloom conditions, affecting the entire ecosystem including the bacterioplankton. Accordingly, the emerging ecological niches during bloom transition are occupied by different bacterial populations, with Roseobacter RCA cluster and SAR92 clade members exhibiting high metabolic activity during bloom events. In this study, the functional response of the ambient bacterial community toward a Phaeocystis globosa bloom in the southern North Sea was studied using metaproteomic approaches. In contrast to other metaproteomic studies of marine bacterial communities, this is the first study comparing two different cell lysis and protein preparation methods [using trifluoroethanol (TFE) and in-solution digest as well as bead beating and SDS-based solubilization and in-gel digest (BB GeLC)]. In addition, two different mass spectrometric techniques (ESI-iontrap MS and MALDI-TOF MS) were used for peptide analysis. A total of 585 different proteins were identified, 296 of which were only detected using the TFE and 191 by the BB GeLC method, demonstrating the complementarity of these sample preparation methods. Furthermore, 158 proteins of the TFE cell lysis samples were exclusively detected by ESI-iontrap MS while 105 were only detected using MALDI-TOF MS, underpinning the value of using two different ionization and mass analysis methods. Notably, 12% of the detected proteins represent predicted integral membrane proteins, including the difficult to detect rhodopsin, indicating a considerable coverage of membrane proteins by this approach. This comprehensive approach verified previous metaproteomic studies of marine bacterioplankton, e.g., detection of many transport-related proteins (17% of the detected proteins). In addition, new insights into e.g., carbon and nitrogen

  9. Reconnaissance of the Pigeon River, a cold-water river in the north-central part of Michigan's southern peninsula

    USGS Publications Warehouse

    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

  10. A regional tephrostratigraphic framework for central and southern European climate archives during the Last Glacial to Interglacial transition: comparisons north and south of the Alps

    NASA Astrophysics Data System (ADS)

    Lane, C. S.; Blockley, S. P. E.; Lotter, A. F.; Finsinger, W.; Filippi, M. L.; Matthews, I. P.

    2012-03-01

    This paper summarises the results of tephrochronological investigations into a suite of central and southern European records, which include: Rotmeer, southern Germany; Soppensee and Rotsee, central Swiss Plateau; Lago di Lavarone and Lago Piccolo di Avigliana, Italian southern Alpine foreland. These sites provide records of palaeoenvironmental changes for the Last Glacial to Interglacial Transition (LGIT) at the boundary between North Atlantic and Mediterranean climatic influences. Chemical characterisation of glass shards in volcanic ash layers indicates that multiple volcanic sources have contributed to the central European tephra record. Amongst other volcanic markers, the Laacher See Tephra, originating from the Eifel region of Germany c. 12.9 ± 0.1 ka, and the Vedde Ash from Iceland c. 12.1 ± 0.1 ka, are found co-located within the sediments of Rotmeer, Soppensee, Rotsee and Lago Piccolo di Avigliana. These key horizons, which bracket the onset of the Younger Dryas stadial, provide precise calendrically-dated tie points around which a detailed picture of the timing of local and regional environmental transitions can be constructed. Using the co-located tephra layers the re-colonisation of Northern Italian catchment areas by Quercus is shown to occur just prior to the deposition of the Laacher See Tephra layer, whereas to the North of the Alps Quercus and other thermophilous trees do not reappear until several centuries after the deposition of the Vedde Ash. Furthermore, the discovery of the Vedde Ash in Lago Piccolo di Avigliana and Lago di Lavarone is indicative of atmospheric transport of polar air into southern Europe during the Younger Dryas stadial, matching evidence proposed for such transport of polar air during the Last Glacial Maximum (LGM).

  11. Tools to evaluate seafloor integrity: comparison of multi-device acoustic seafloor classifications for benthic macrofauna-driven patterns in the German Bight, southern North Sea

    NASA Astrophysics Data System (ADS)

    Holler, Peter; Markert, Edith; Bartholomä, Alexander; Capperucci, Ruggero; Hass, H. Christian; Kröncke, Ingrid; Mielck, Finn; Reimers, H. Christian

    2017-04-01

    To determine the spatial resolution of sediment properties and benthic macrofauna communities in acoustic backscatter, the suitability of four acoustic seafloor classification devices (single-beam echosounder with RoxAnn and QTC 5.5 seafloor classification system, sidescan sonar with QTC Swathview seafloor classification, and multi-beam echosounder with QTC Swathview seafloor classification) was compared in a study area of approx. 6 km2 northwest of the island of Helgoland in the German Bight, southern North Sea. This was based on a simple similarity index between simultaneous sidescan sonar, single-beam echosounder and multi-beam echosounder profiling spanning the period 2011-2014. The results show a high similarity between seafloor classifications based on sidescan sonar and RoxAnn single-beam systems, in turn associated with a lower similarity for the multi-beam echosounder system. Analyses of surface sediment samples at 39 locations along four transects (0.1 m2 Van Veen grab) revealed the presence of sandy mud (southern and western parts), coarse sand, gravel and cobbles. Rock outcrops were identified in the north-eastern and eastern parts. A typical Nucula nitidosa- Abra alba community was found in sandy muds to muddy sands in the northern part, whereas the southern part is characterised by widespread occurrence of the ophiuroid brittle star Amphiura filiformis. A transitional N. nitidosa- A. filiformis community was detected in the central part. Moreover, the southern part is characterised by a high abundance of A. filiformis and its commensal bivalve Kurtiella bidentata. The high number of A. filiformis feeding arms (up to ca. 6,800 per m2) can largely explain the gentle change of backscatter intensity along the tracks, because sediment composition and/or seafloor structures showed no significant variability.

  12. Tools to evaluate seafloor integrity: comparison of multi-device acoustic seafloor classifications for benthic macrofauna-driven patterns in the German Bight, southern North Sea

    NASA Astrophysics Data System (ADS)

    Holler, Peter; Markert, Edith; Bartholomä, Alexander; Capperucci, Ruggero; Hass, H. Christian; Kröncke, Ingrid; Mielck, Finn; Reimers, H. Christian

    2016-12-01

    To determine the spatial resolution of sediment properties and benthic macrofauna communities in acoustic backscatter, the suitability of four acoustic seafloor classification devices (single-beam echosounder with RoxAnn and QTC 5.5 seafloor classification system, sidescan sonar with QTC Swathview seafloor classification, and multi-beam echosounder with QTC Swathview seafloor classification) was compared in a study area of approx. 6 km2 northwest of the island of Helgoland in the German Bight, southern North Sea. This was based on a simple similarity index between simultaneous sidescan sonar, single-beam echosounder and multi-beam echosounder profiling spanning the period 2011-2014. The results show a high similarity between seafloor classifications based on sidescan sonar and RoxAnn single-beam systems, in turn associated with a lower similarity for the multi-beam echosounder system. Analyses of surface sediment samples at 39 locations along four transects (0.1 m2 Van Veen grab) revealed the presence of sandy mud (southern and western parts), coarse sand, gravel and cobbles. Rock outcrops were identified in the north-eastern and eastern parts. A typical Nucula nitidosa-Abra alba community was found in sandy muds to muddy sands in the northern part, whereas the southern part is characterised by widespread occurrence of the ophiuroid brittle star Amphiura filiformis. A transitional N. nitidosa-A. filiformis community was detected in the central part. Moreover, the southern part is characterised by a high abundance of A. filiformis and its commensal bivalve Kurtiella bidentata. The high number of A. filiformis feeding arms (up to ca. 6,800 per m2) can largely explain the gentle change of backscatter intensity along the tracks, because sediment composition and/or seafloor structures showed no significant variability.

  13. Holocene relative sea-level change, isostatic subsidence and the radial viscosity structure of the mantle of northwest Europe (Belgium, the Netherlands, Germany, southern North Sea)

    NASA Astrophysics Data System (ADS)

    Vink, Annemiek; Steffen, Holger; Reinhardt, Lutz; Kaufmann, Georg

    2007-12-01

    A comprehensive observational database of Holocene relative sea-level (RSL) index points from northwest Europe (Belgium, the Netherlands, northwest Germany, southern North Sea) has been compiled in order to compare and reassess the data collected from the different countries/regions and by different workers on a common time-depth scale. RSL rise varies in magnitude and form between these regions, revealing a complex pattern of differential crustal movement which cannot be solely attributed to tectonic activity. It clearly contains a non-linear, glacio- and/or hydro-isostatic subsidence component, which is only small on the Belgian coastal plain but increases significantly to a value of ca 7.5 m relative to Belgium since 8 cal. ka BP along the northwest German coast. The subsidence is at least in part related to the Post-Glacial collapse of the so-called peripheral forebulge which developed around the Fennoscandian centre of ice loading during the Last Glacial Maximum. The RSL data have been compared to geodynamic Earth models in order to infer the radial viscosity structure of the Earth's mantle underneath NW Europe (lithosphere thickness, upper- and lower-mantle viscosity), and conversely to predict RSL in regions where we have only few observational data (e.g. in the southern North Sea). A very broad range of Earth parameters fit the Belgian RSL data, suggesting that glacial isostatic adjustment (GIA) only had a minor effect on Belgian crustal dynamics during and after the Last Ice Age. In contrast, a narrow range of Earth parameters define the southern North Sea region, reflecting the greater influence of GIA on these deeper/older samples. Modelled RSL data suggest that the zone of maximum forebulge subsidence runs in a relatively narrow, WNW-ESE trending band connecting the German federal state of Lower Saxony with the Dogger Bank area in the southern North Sea. Identification of the effects of local-scale factors such as past changes in tidal range or tectonic

  14. Acid deposition sensitivity map of the Southern Appalachian Assessment area; Virginia, North Carolina, South Carolina, Tennessee, Georgia, and Alabama

    USGS Publications Warehouse

    Pepper, John D.; Grosz, Andrew E.; Kress, Thomas H.; Collins, Thomas K.; Kappesser, Gary B.; Huber, Cindy M.; Webb, James R.

    1995-01-01

    Project Summary: The following digital product represents the Acid Deposition Sensitivity of the Southern Appalachian Assessment Area. Areas having various susceptibilities to acid deposition from air pollution are designated on a three tier ranking in the region of the Southern Appalachian Assessment (SAA). The assessment is being conducted by Federal agencies that are members of the Southern Appalachian Man and Biosphere (SAMAB) Cooperative. Sensitivities to acid deposition, ranked high, medium, and low are assigned on the basis of bedrock compositions and their associated soils, and their capacities to neutralize acid precipitation.

  15. Commercial fishing gear modifications to reduce interactions between Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) and the southern flounder (Paralichthys lethostigma) fishery in North Carolina (USA).

    PubMed

    Levesque, Juan C; Hager, Christian; Diaddorio, Eric; Dickey, R Jason

    2016-01-01

    Bycatch of protected species in commercial fishing operations is a primary concern to fishery managers because it threatens the conservation, protection, and recovery of fragile species, such as the Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus). One potential solution to reduce the risk associated with commercial fishing operations is to design commercial fishing gear that is more selective in terms of interactions between Atlantic sturgeon and commercial fisheries. Given this conservation and management need, the overarching goal was to reduce Atlantic sturgeon fishery interactions and maintain southern flounder (Paralichthys lethostigma) catch in North Carolina. The specific objectives of this study were to design and evaluate the effectiveness of a modified gillnet. Overall, the results proved that lowering the profile and amount of webbing had a beneficial impact at reducing Atlantic sturgeon incidental encounters and bycatch. The modified gillnet reduced bycatch and Atlantic sturgeon encounters by 39.6% and 60.9%, respectively. Our design entangled 51.6% fewer southern flounder, which corresponded to a 48.9% reduction in total weight; the modified gear entangled slightly larger southern flounder than the control gear. Our findings showed the number of Atlantic sturgeon encounters was positively associated with mean water depth, with more Atlantic sturgeon encountered in deeper (5.1-6.3 m) than shallower waters; 75% were encountered at depths between 4.6 and 6.1 m. Most southern flounder (n = 518, 39.7%) were taken at a water depth between 3.76 and 5.0 m. This observation suggests that southern flounder prefer slightly shallower waters than Atlantic sturgeon.

  16. Commercial fishing gear modifications to reduce interactions between Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) and the southern flounder (Paralichthys lethostigma) fishery in North Carolina (USA)

    PubMed Central

    Hager, Christian; Diaddorio, Eric; Dickey, R. Jason

    2016-01-01

    Bycatch of protected species in commercial fishing operations is a primary concern to fishery managers because it threatens the conservation, protection, and recovery of fragile species, such as the Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus). One potential solution to reduce the risk associated with commercial fishing operations is to design commercial fishing gear that is more selective in terms of interactions between Atlantic sturgeon and commercial fisheries. Given this conservation and management need, the overarching goal was to reduce Atlantic sturgeon fishery interactions and maintain southern flounder (Paralichthys lethostigma) catch in North Carolina. The specific objectives of this study were to design and evaluate the effectiveness of a modified gillnet. Overall, the results proved that lowering the profile and amount of webbing had a beneficial impact at reducing Atlantic sturgeon incidental encounters and bycatch. The modified gillnet reduced bycatch and Atlantic sturgeon encounters by 39.6% and 60.9%, respectively. Our design entangled 51.6% fewer southern flounder, which corresponded to a 48.9% reduction in total weight; the modified gear entangled slightly larger southern flounder than the control gear. Our findings showed the number of Atlantic sturgeon encounters was positively associated with mean water depth, with more Atlantic sturgeon encountered in deeper (5.1–6.3 m) than shallower waters; 75% were encountered at depths between 4.6 and 6.1 m. Most southern flounder (n = 518, 39.7%) were taken at a water depth between 3.76 and 5.0 m. This observation suggests that southern flounder prefer slightly shallower waters than Atlantic sturgeon. PMID:27547524

  17. Evidence for orbital and North Atlantic climate forcing in alpine Southern California between 125 and 10 ka from multi-proxy analyses of Baldwin Lake

    NASA Astrophysics Data System (ADS)

    Glover, Katherine C.; MacDonald, Glen M.; Kirby, Matthew E.; Rhodes, Edward J.; Stevens, Lora; Silveira, Emily; Whitaker, Alexis; Lydon, Scott

    2017-07-01

    We employed a new, multi-proxy record from Baldwin Lake (∼125-10 ka) to examine drivers of terrestrial Southern California climate over long timescales. Correlated bulk organic and biogenic silica proxy data demonstrated high-amplitude changes from 125 to 71 ka, suggesting that summer insolation directly influenced lake productivity during MIS 5. From 60 to 57 ka, hydrologic state changes and events occurred in California and the U.S. Southwest, though the pattern of response varied geographically. Intermediate, less variable levels of winter and summer insolation followed during MIS 3 (57-29 ka), which likely maintained moist conditions in Southern California that were punctuated with smaller-order, millennial-scale events. These Dansgaard-Oeschger events brought enhanced surface temperatures (SSTs) to the eastern Pacific margin, and aridity to sensitive terrestrial sites in the Southwest and Southern California. Low temperatures and reduced evaporation are widespread during MIS 2, though there is increasing evidence for moisture extremes in Southern California from 29 to 20 ka. Our record shows that both orbital-scale radiative forcing and rapid North Atlantic temperature perturbations were likely influences on Southern California climate prior to the last glacial. However, these forcings produced a hydroclimatic response throughout California and the U.S. Southwest that was geographically complex. This work highlights that it is especially urgent to improve our understanding of the response to rapid climatic change in these regions. Enhanced temperature and aridity are projected for the rest of the 21st century, which will place stress on water resources.

  18. Spatio-temporal pattern of eco-environmental parameters in Jharia coalfield, India

    NASA Astrophysics Data System (ADS)

    Saini, V.; Gupta, R. P.; Arora, M. K.

    2015-10-01

    Jharia coal-field holds unequivocal importance in the Indian context as it is the only source of prime coking coal in the country. The coalfield is also known for its infamous coal mine fires which have been burning since last more than a century. Haphazard mining over a century has led to eco-environmental changes to a large extent such as changes in vegetation distribution and widespread development of surface and subsurface fires. This article includes the spatiotemporal study of remote sensing derived eco-environmental parameters like vegetation index (NDVI), tasseled cap transformation (TCT) and temperature distribution in fire areas. In order to have an estimate of the temporal variations of NDVI over the years, a study has been carried out on two subsets of the Jharia coalfield using Landsat images of 1972 (MSS), 1992 (TM), 1999 (ETM+) and 2013 (OLI). To assess the changes in brightness and greenness over the year s, difference images have been calculated using the 1992 (TM) and 2013 (OLI) images. Radiance images derived from thermal bands have been used to calculate at-sensor brightness temperature over a 23 year period from 1991 to 2013. It has been observed that during the years 1972 to 2013, moderate to dense vegetation has decreased drastically due to the intense mining going on in the area. TCT images show the areas that have undergone changes in both brightness and greenness from 1992 to 2013. Surface temperature data obtained shows a constant increase from 1991 to 2013 apparently due to coal fires. The utility of remote sensing data in such EIA studies has been emphasized.

  19. The problems of the kinematic restoration of hyper-extended rifted margins: the example of the southern North-Atlantic

    NASA Astrophysics Data System (ADS)

    Nirrengarten, Michael; Manatschal, Gianreto; Tugend, Julie; Kusznir, Nick

    2016-04-01

    The development in space and time of hyper-extended lithosphere is fundamental to our understanding of the 3D development and propagation of rifting and lithospheric breakup. Hyper-extended domains, consisting of extremely thinned continental crust and exhumed mantle with possible minor magmatic addition, often extend over wide areas, sometimes up to 400 km, continentward of the first unequivocal oceanic crust. Although considerable work has been done in the last decades to describe the evolution of hyper-extended domains, there is yet no generally accepted approach to kinematically restore them. Indeed, in contrast to oceanic crust, where the kinematics can be defined by isochronal magnetic anomalies, in hyper-extended well-defined consistent magnetic anomalies are lacking. Therefore in order to restore these domains, we need to define alternative approaches. The main questions to be addressed to solve this problem are: 1) how can hyper-extended domains be restored, 2) which kinematic markers could be used 3) what are the implications for the 3D propagation of hyper-extended systems. We use the example of the southern North-Atlantic to develop and apply an approach to kinematically analyse the evolution of hyper-extended domains. We combine seismic dataset and drill hole data available with crustal thickness maps determined from gravity inversion to define and map rift domains and rift domain boundaries. We distinguish between the proximal domain (weakly thinned continental crust), thinned continental crust, exhumed mantle, and oceanic crust. From this mapping, we observe that the width of each domain is variable along the margins and that domain boundaries are not always straight lines. It implies that these boundaries, in particular the edge of the continental crust cannot be easily superimposed at a specific time. Therefore, rift domain boundaries cannot be considered as isochrones and do not represent kinematical markers. The restoration of hyper

  20. Marine Fouling Assemblages on Offshore Gas Platforms in the Southern North Sea: Effects of Depth and Distance from Shore on Biodiversity.

    PubMed

    van der Stap, Tim; Coolen, Joop W P; Lindeboom, Han J

    2016-01-01

    Offshore platforms are known to act as artificial reefs, though there is on-going debate on whether this effect is beneficial or harmful for the life in the surrounding marine environment. Knowing what species exist on and around the offshore platforms and what environmental variables influence this species assemblage is crucial for a better understanding of the impact of offshore platforms on marine life. Information on this is limited for offshore platforms in the southern North Sea. This study aims to fill this gap in our knowledge and to determine how the composition and the abundance of species assemblages changes with depth and along a distance-from-shore gradient. The species assemblages on five offshore gas platforms in the southern North Sea have been inventoried using Remotely Operated Vehicles inspection footage. A total of 30 taxa were identified. A Generalised Additive Model of the species richness showed a significant non-linear relation with water depth (p = 0.001): from a low richness in shallow waters it increases with depth until 15-20 m, after which richness decreases again. Using PERMANOVA, water depth (p≤0.001), community age (p≤0.001) and the interaction between distance from shore and community age (p≤0.001) showed a significant effect on the species assemblages. Future research should focus on the effect additional environmental variables have on the species assemblages.

  1. Marine Fouling Assemblages on Offshore Gas Platforms in the Southern North Sea: Effects of Depth and Distance from Shore on Biodiversity

    PubMed Central

    van der Stap, Tim; Coolen, Joop W. P.; Lindeboom, Han J.

    2016-01-01

    Offshore platforms are known to act as artificial reefs, though there is on-going debate on whether this effect is beneficial or harmful for the life in the surrounding marine environment. Knowing what species exist on and around the offshore platforms and what environmental variables influence this species assemblage is crucial for a better understanding of the impact of offshore platforms on marine life. Information on this is limited for offshore platforms in the southern North Sea. This study aims to fill this gap in our knowledge and to determine how the composition and the abundance of species assemblages changes with depth and along a distance-from-shore gradient. The species assemblages on five offshore gas platforms in the southern North Sea have been inventoried using Remotely Operated Vehicles inspection footage. A total of 30 taxa were identified. A Generalised Additive Model of the species richness showed a significant non-linear relation with water depth (p = 0.001): from a low richness in shallow waters it increases with depth until 15–20 m, after which richness decreases again. Using PERMANOVA, water depth (p≤0.001), community age (p≤0.001) and the interaction between distance from shore and community age (p≤0.001) showed a significant effect on the species assemblages. Future research should focus on the effect additional environmental variables have on the species assemblages. PMID:26745870

  2. Characterizing Mineral Crystallographic Preferred Orientations (CPOs) Along the Eastern North American Margin in the Southern Appalachians: Implications for Middle and Lower Crustal Seismic Anisotropy

    NASA Astrophysics Data System (ADS)

    Robles, Laura

    The Southern Appalachians Mountains have a complex and distinctive tectonic history, characterized by structural deformation extending from late Precambrian throughout the Paleozoic. The Southern Appalachians, known as the Blue Ridge of western North Carolina and eastern Tennessee, is mainly composed of schists and gneisses, granitic and ultramafic intrusives, as well as a sedimentary portion. The main tool for understanding the composition and structure of the deeper parts of the crust that cannot be directly sampled by seismology. Seismic anisotropy is the directional dependence of seismic velocity, and it is an invaluable tool for interpreting the development of sub-surficial dynamics. Seismic anisotropy can have a number of controlling parameters including shear strain, mineral grain aspect ratios, and aligned cracks, and crystallographic preferred orientations. If these parameters are known, we can use anisotropy to constrain lower and middle crustal composition. In an effort to characterize the southern Appalachian region's compositional and structural variability, we will present results from calculations of elastic tensors derived from electron backscatter diffraction (EBSD) data from a variety of metamorphic rocks with different mineral compositions. Here we will report analyses from 14 samples that are distributed into two transects across the Blue Ridge. Our goal is to address how deformational fabric controls the strength of mineral CPOs and thus seismic anisotropy.

  3. Characterizing mineral crystallographic preferred orientations (CPOs) along the Eastern North American Margin in the southern Appalachians: Implications for middle and lower crustal seismic anisotropy

    NASA Astrophysics Data System (ADS)

    Robles, L.; Brownlee, S. J.

    2016-12-01

    The Southern Appalachians Mountains have a complex and distinctive tectonic history, characterized by structural deformation extending from late Precambrian throughout the Paleozoic. The Southern Appalachians, known as the Blue Ridge of western North Carolina and eastern Tennessee, is mainly composed of schists and gneisses, granitic and ultramafic intrusives, as well as a sedimentary portion. The main tool for understanding the composition and structure of the deeper parts of the crust that cannot be directly sampled is seismology. Seismic anisotropy is the directional dependence of seismic velocity, and it is an invaluable tool for interpreting the development of sub-surficial dynamics. Seismic anisotropy can have a number of controlling parameters including shear strain, mineral grain aspect ratios, and aligned cracks, and crystallographic preferred orientations. If these parameters are known, we can use anisotropy to constrain lower and middle crustal composition. In an effort to characterize the southern Appalachian region's compositional and structural variability, we will present results from calculations of elastic tensors derived from electron backscatter diffraction (EBSD) data from a variety of metamorphic rocks with different mineral compositions. Here we will report analyses from 14 samples that are distributed into two transects across the Blue Ridge. Our goal is to address how mineral CPOs vary through these transects depending on rock composition and location within the Blue Ridge province.

  4. The Links Between the Formation of the Gulf of Mexico and the Late Proterozoic to Mesozoic Tectonic Evolution of Southern North America

    NASA Astrophysics Data System (ADS)

    Keller, G. R.; Mickus, K. L.; Gurrola, H.; Harry, D. L.; Pulliam, J.

    2016-12-01

    A full understanding of the Gulf of Mexico's geologic history depends on understanding the tectonic framework along the southern margin of North America. The first step in establishing this framework was the breakup of Laurentia during the Early Paleozoic. At least one tectonic block rifted away from Laurentia's southern margin at this time, and is interpreted to be presently located in Argentina. Rifting resulted in a sinuous margin consisting of alternating ridge and transform segments extending from the southeastern U.S. across Texas into northern Mexico. The Paleozoic margin is associated with a clearly defined gravity high, and ends in the trend of this high are associated with intersections of ridge and transform segments along the margin. By the end of the Paleozoic, continental assembly via the Appalachian-Ouachita orogeny added new terranes to the eastern and southern margins of Laurentia and the assembly of the supercontinent Pangea was complete. Triassic through Late Jurassic opening of the Gulf of Mexico (GOM) created a complex margin, initially mobilizing several crustal blocks that were eventually left behind on the North American margin as seafloor spreading developed within the Gulf and the Yucatan block separated and rotated into its current position. Recent deep seismic reflection profiles along the northern margin of the GOM show that rifted continental crust extends offshore for 250 km before the oceanic crust of the Gulf of Mexico is encountered. Our group has worked to produce four integrated models of the lithospheric structure based upon reflection, refraction, and teleseismic data acquired across this margin integrated with gravity, magnetic, geologic and drilling data. These models define a complex zone of crustal thinning along the Gulf Coastal plain of Texas that is covered by up to 10km of primarily Cretaceous and younger sedimentary rocks. To the east along the coastal plain region, we have defined two large crustal blocks that were

  5. Iron and silicic acid concentrations regulate Si uptake north and south of the Polar Frontal Zone in the Pacific Sector of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Franck, Valerie M.; Brzezinski, Mark A.; Coale, Kenneth H.; Nelson, David M.

    We investigated the relative roles of Fe and silicic acid availabilities in regulating Si uptake rates across the Polar Frontal Zone in the Pacific Sector of the Southern Ocean (59-68°S, 170°W) during the US JGOFS Antarctic Environment Southern Ocean Process Study (AESOPS). Meridional gradients in silicic acid concentration ([Si(OH) 4]) of about 0.25-0.56 μM km -1 were observed in this area during austral spring and summer, 1997-1998, with [Si(OH) 4] ranging from <1 to 15 μM on the north side of the gradient to 40-60 μM on the south side. In two pairs of shipboard bottle-enrichment experiments conducted north and south of the Si gradient in spring and summer, we measured the effects of Fe, Zn and Si additions on 32Si(OH)4 and 15NO3- uptake rates, biogenic silica concentrations and Si(OH) 4 : NO 3- uptake ratios. Fe addition had little or no effect on Si uptake rates in enrichments conducted in the low-Si waters north of the Si gradient. However, Fe addition increased Si uptake rates 3-5 times over controls in enrichments conducted in the high-Si waters south of the gradient, in both spring and summer. Fe addition decreased Si(OH) 4 : NO 3- uptake ratios by 2-5 times, largely due to stimulation of NO 3- uptake rates. Zn addition had no effect on Si(OH) 4 and NO 3- uptake rates. Short-term (24 h) Si additions had varying effects on Si uptake rates, depending on season and location. In spring, additions of 40 μM Si to water from bottle enrichments, conducted north of the Si gradient (in situ [Si(OH) 4] ˜15 μM) did not increase Si uptake rates initially, but did increase uptake rates after 8 days. In the summer enrichment north of the Si gradient (in situ [Si(OH) 4] ˜5 μM), 50 μM Si additions doubled in situ Si uptake rates in the initial water collected for the enrichment, and increased Si uptake rates as much as 16-fold during the experiment. South of the Si gradient, where in situ [Si(OH) 4] was >40 μM in both spring and summer, Si addition had no effect

  6. Defining habitats suitable for larval fish in the German Bight (southern North Sea): An IBM approach using spatially- and temporally-resolved, size-structured prey fields

    NASA Astrophysics Data System (ADS)

    Kühn, Wilfried; Peck, Myron A.; Hinrichsen, Hans-Harald; Daewel, Ute; Moll, Andreas; Pohlmann, Thomas; Stegert, Christoph; Tamm, Susanne

    2008-11-01

    We employed a coupled biological-physical, individual-based model (IBM) to estimate spatial and temporal changes in larval fish habitat suitability (the potential for areas to support survival and high rates of growth) of the German Bight, southern North Sea. In this Lagrangian approach, larvae were released into a size-structured prey field that was constructed from in situ measurements of the abundance and prosome lengths of stages of three copepods ( Acartia spp., Temora longicornis, Pseudocalanus elongatus) collected on a station grid repeatedly sampled from February to October 2004. The choice of prey species and the model parameterisations for larval fish foraging and growth were based on field data collected for sprat ( Sprattus sprattus) and other clupeid larvae. A series of 10-day simulations were conducted using 20 release locations to quantify spatial-temporal differences in projected larval sprat growth rates (mm d - 1) for mid-April, mid-May and mid-June 2004. Based upon an optimal foraging approach, modeled sprat growth rates agreed well with those measured in situ using larval fish ototliths. On the German GLOBEC station grid, our model predicted areas that were mostly unsuitable habitats (areas of low growth potential), e.g. north of the Frisian Islands, and others that were consistently suitable habitats (areas that had high growth potential), e.g. in the inner German Bight. In some instances, modelled larvae responded rapidly (~ 5 days) to changing environmental characteristics experienced along their drift trajectory, a result that appears reasonable given the dynamic nature of frontal regions such as our study area in the southern North Sea.

  7. Map showing general chemical quality of surface water in the Alton-Kolob coal-fields area, Utah

    USGS Publications Warehouse

    Price, Don

    1980-01-01

    This is one of a series of maps that describes the geology and related natural resources of the Alton-Kolob coal-fields area, Utah. The purpose of this map is to show the general chemical quality of surface water in the area by ranges of dissolved-solids concentrations (salinity) known or assumed to occur in the water.

  8. "Non-Servile Virtuosi" in Insubordinate Spaces: School Disaffection, Refusal and Resistance in a Former English Coalfield

    ERIC Educational Resources Information Center

    Bright, N. Geoffrey

    2011-01-01

    This article reviews excerpts from a body of ethnographic data examining some young people's disaffection from, and refusal of, the education project as a whole in a UK coalfield area. Key examples are used to illustrate intergenerational continuities and disjunctions in attitudes to formal education in these exceptional and sometimes…

  9. The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields (2011 Final)

    EPA Science Inventory

    EPA announced the availability of the final report, The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields. This report assesses the state of the science on the environmental impacts of mountaintop mines and valley ...

  10. The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields (External Review Draft)

    EPA Science Inventory

    This report assesses the state of the science on the environmental impacts of mountaintop mines and valley fills (MTM-VF) on streams in the Central Appalachian Coalfields. Our review focused on the aquatic impacts of mountaintop removal coal mining, which, as its name suggests, ...

  11. The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields (2011 Final)

    EPA Science Inventory

    EPA announced the availability of the final report, The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields. This report assesses the state of the science on the environmental impacts of mountaintop mines and valley ...

  12. The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields (External Review Draft)

    EPA Science Inventory

    This report assesses the state of the science on the environmental impacts of mountaintop mines and valley fills (MTM-VF) on streams in the Central Appalachian Coalfields. Our review focused on the aquatic impacts of mountaintop removal coal mining, which, as its name suggests, ...

  13. The central branch of the North Anatolian Fault In The Southern Marmara Sea: Evidence for a distributed, Holocene-active fault system

    NASA Astrophysics Data System (ADS)

    Barın, Burcu; Okay, Seda; Çifçi, Günay; Dondurur, Derman; Cormier, Marie Helene; Sorlien, Christopher; Meriç İlkimen, Elif

    2015-04-01

    The North Anatolian Fault (NAF) is a major right-lateral transform fault in northern Turkey that branches westward into several strands in the vicinity of the Sea of Marmara. The main northern branch bisects the Marmara Sea from east to west, and seismic reflection profiles acquired over the past 15 years have revealed its complex geometry. Further, the several basins that developed along that branch record stratigraphic sequences that provide the needed framework to interpret the relative timing of tectonic deformation in the Marmara Sea. In contrast, the central branch, which snakes across the shallow southern shelf of the Marmara Sea, has been much less investigated. Here, we analyze a comprehensive dataset of high-resolution multi-channel, sparker, and CHIRP seismic profiles, which were collected with the facilities of Seismic Laboratory (SeisLab) in the Institute of Marine Sciences and Technology and R/V K. Piri Reis belonging to Dokuz Eylül University, along the central branch in 2008 (TAMAM expedition) and in 2013-2014 (SoMAR expedition), within the framework of a bilateral TÜBİTAK - NSF project. In combination with other existing seismic profiles, these new data reveal that the Central Branch consists of multiple faults strands that are distributed across the broad southern shelf. They also reveal that many of these strands are Holocene-active, although they slip at slower rates than the northern branch and are associated with slower basin subsidence or local uplift. Lastly, seismic data image a system of half-grabens across the southern shelf that are associated with the strands of the central branch. Strata within these half-grabens are progressively tilted and consistently dip to the south. Further analysis will be conducted to determine whether the formation of these grabens are controlled by oblique slip on the strands of the central branch, or by slip on detachment faults beneath the southern shelf.

  14. Ambient Air Quality Assessment with Particular Reference to Particulates in Jharia Coalfield, Eastern India.

    PubMed

    Singh, Gurdeep; Roy, Debananda; Sinha, Sweta

    2014-01-01

    Jharia Coalfield is the critically polluted area with the intense mining and associated industrial activities. There has been widespread concern of particulate pollution with the alarming levels of Suspended Particulate Matter (SPM) and Respirable Particulate Matter (PM10 & PM2.5). Coke oven plants, coal washing, thermal power stations and associated activities coupled with the transportation activities, give rise to critical air pollution levels in the region. This study envisages the assessment of air pollution of the region with particular reference to SPM, PM10 and PM2.5. Eighteen monitoring stations were selected considering various sources of pollution such as mining, industrial, commercial and residential areas apart from siting criteria as per IS: 5182 Part XIV. Air quality monitoring was carried out following standard methodologies and protocols as per Central Pollution Control Board (CPCB)/ National Ambient Air Quality Standard (NAAQS) norms using Respirable Dust Samplers (RDS) and Fine Particulate Samplers (PM2.5 Samplers). This study reveals considerable load of particulates (SPM, PM10, PM 2.5) which exceed not only the NAAQS but also the coal mining areas standards of Jharia coalfield, thus falling under the category of critically polluted area. Air Quality Indexing has also been developed which provides a clear map of the deterioration of air quality and also presenting comparative ranking of all the monitoring locations with respect to air quality status in the study area.

  15. Effects of microhabitat and land use on stream salamander abundance in the southwest Virginia coalfields

    USGS Publications Warehouse

    Sweeten, Sara E.; Ford, William

    2015-01-01

    Large-scale land uses such as residential wastewater discharge and coal mining practices, particularly surface coal extraction and associated valley fills, are of particular ecological concern in central Appalachia. Identification and quantification of both alterations across scales are a necessary first-step to mitigate negative consequences to biota. In central Appalachian headwater streams absent of fish, salamanders are the dominant, most abundant vertebrate predator providing a significant intermediate trophic role. Stream salamander species are considered to be sensitive to aquatic stressors and environmental alterations, and past research has shown linkages among microhabitat parameters, large-scale land use such as urbanization and logging with salamander abundances. However, little is known about these linkages in the coalfields of central Appalachia. In the summer of 2013, we visited 70 sites (sampled three times each) in the southwest Virginia coalfields to survey salamanders and quantify stream and riparian microhabitat parameters. Using an information-theoretic framework we compared the effects of microhabitat and large-scale land use on salamander abundances. Our findings indicate that dusky salamander (Desmognathus spp.) abundances are more correlated to microhabitat parameters such as canopy cover than to subwatershed land uses. Brook salamander (Eurycea spp.) abundances show strong negative associations to the suspended sediments and stream substrate embeddedness. Neither Desmognathus spp. nor Eurycea spp. abundances were influenced by water conductivity. These suggest protection or restoration of riparian habitats and erosion control is an important conservation component for maintaining stream salamanders in the mined landscapes of central Appalachia.

  16. Clean Power Generation from the Intractable Natural Coalfield Fires: Turn Harm into Benefit.

    PubMed

    Shi, Bobo; Su, Hetao; Li, Jinshi; Qi, Haining; Zhou, Fubao; Torero, José L; Chen, Zhongwei

    2017-07-13

    The coal fires, a global catastrophe for hundreds of years, have been proved extremely difficult to control, and hit almost every coal-bearing area globally. Meanwhile, underground coal fires contain tremendous reservoir of geothermal energy. Approximately one billion tons of coal burns underground annually in the world, which could generate ~1000 GW per annum. A game-changing approach, environmentally sound thermal energy extraction from the intractable natural coalfield fires, is being developed by utilizing the waste energy and reducing the temperature of coalfield fires at the same time. Based on the Seebeck effect of thermoelectric materials, the temperature difference between the heat medium and cooling medium was employed to directly convert thermal energy into clean electrical energy. By the time of December 2016, the power generation from a single borehole at Daquan Lake fire district in Xinjiang has been exceeded 174.6 W. The field trial demonstrates that it is possible to exploit and utilize the waste heat resources in the treated coal fire areas. It promises a significant impact on the structure of global energy generation and can also promote progress in thermoelectric conversion materials, geothermal exploration, underground coal fires control and other energy related areas.

  17. Arbuscular mycorrhizal fungi enhance soil carbon sequestration in the coalfields, northwest China

    PubMed Central

    Wang, Zhi-Gang; Bi, Yin-Li; Jiang, Bin; Zhakypbek, Yryszhan; Peng, Su-Ping; Liu, Wen-Wen; Liu, Hao

    2016-01-01

    Carbon storage is affected by photosynthesis (Pn) and soil respiration (Rs), which have been studied extensively in natural and agricultural systems. However, the effects of Pn and Rs on carbon storages in the presence of arbuscular mycorrhizal fungi (AMF) in coalfields remain unclear. A field experiment was established in 2014 in Shendong coal mining subsidence area. The treatments comprised two inoculation levels (inoculated with or without 100 g AMF inoculums per seedlings) and four plant species [wild cherry (Prunus discadenia Koebne L.), cerasus humilis (Prunus dictyneura Diels L.), shiny leaf Yellow horn (Xanthoceras sorbifolium Bunge L.) and apricot (Armeniaca sibirica L.)]. AMF increased Pn of four species ranging from 15.3% to 33.1% and carbon storage, averaged by 17.2% compared to controls. Soil organic carbon (OC), easily extractable glomalin-relation soil protein (EE-GRSP), and total glomalin-relation soil protein (T-GRSP) were significantly increased by AMF treatment. The effect of AMF on the sensitivity of Rs depended on soil temperature. The results highlighted the exponential models to explain the responses of Rs to soil temperature, and for the first time quantified AMF caused carbon sequestration and Rs. Thus, to our knowledge, AMF is beneficial to ecosystems through facilitating carbon conservation in coalfield soils. PMID:27748365

  18. Geochemistry of environmentally sensitive trace elements in Permian coals from the Huainan coalfield, Anhui, China

    USGS Publications Warehouse

    Chen, J.; Liu, Gaisheng; Jiang, M.; Chou, C.-L.; Li, H.; Wu, B.; Zheng, Lingyun; Jiang, D.

    2011-01-01

    To study the geochemical characteristics of 11 environmentally sensitive trace elements in the coals of the Permian Period from the Huainan coalfield, Anhui province, China, borehole samples of 336 coals, two partings, and four roof and floor mudstones were collected from mineable coal seams. Major elements and selected trace elements were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), and hydride generation atomic absorption spectrometry (HAAS). The depositional environment, abundances, distribution, and modes of occurrence of trace elements were investigated. Results show that clay and carbonate minerals are the principal inorganic constituents in the coals. A lower deltaic plain, where fluvial channel systems developed successively, was the likely depositional environment of the Permian coals in the Huainan coalfield. All major elements have wider variation ranges than those of Chinese coals except for Mg and Fe. The contents of Cr, Co, Ni, and Se are higher than their averages for Chinese coals and world coals. Vertical variations of trace elements in different formations are not significant except for B and Ba. Certain roof and partings are distinctly higher in trace elements than underlying coal bench samples. The modes of occurrence of trace elements vary in different coal seams as a result of different coal-forming environments. Vanadium, Cr, and Th are associated with aluminosilicate minerals, Ba with carbonate minerals, and Cu, Zn, As, Se, and Pb mainly with sulfide minerals. ?? 2011 Elsevier B.V.

  19. Arbuscular mycorrhizal fungi enhance soil carbon sequestration in the coalfields, northwest China

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Gang; Bi, Yin-Li; Jiang, Bin; Zhakypbek, Yryszhan; Peng, Su-Ping; Liu, Wen-Wen; Liu, Hao

    2016-10-01

    Carbon storage is affected by photosynthesis (Pn) and soil respiration (Rs), which have been studied extensively in natural and agricultural systems. However, the effects of Pn and Rs on carbon storages in the presence of arbuscular mycorrhizal fungi (AMF) in coalfields remain unclear. A field experiment was established in 2014 in Shendong coal mining subsidence area. The treatments comprised two inoculation levels (inoculated with or without 100 g AMF inoculums per seedlings) and four plant species [wild cherry (Prunus discadenia Koebne L.), cerasus humilis (Prunus dictyneura Diels L.), shiny leaf Yellow horn (Xanthoceras sorbifolium Bunge L.) and apricot (Armeniaca sibirica L.)]. AMF increased Pn of four species ranging from 15.3% to 33.1% and carbon storage, averaged by 17.2% compared to controls. Soil organic carbon (OC), easily extractable glomalin-relation soil protein (EE-GRSP), and total glomalin-relation soil protein (T-GRSP) were significantly increased by AMF treatment. The effect of AMF on the sensitivity of Rs depended on soil temperature. The results highlighted the exponential models to explain the responses of Rs to soil temperature, and for the first time quantified AMF caused carbon sequestration and Rs. Thus, to our knowledge, AMF is beneficial to ecosystems through facilitating carbon conservation in coalfield soils.

  20. Fuel reduction treatments affect stand structure of hardwood forests in Western North Carolina and Southern Ohio, USA

    Treesearch

    Thomas A. Waldrop; Daniel A. Yaussy; Ross J. Phillips; Todd A. Hutchinson; Lucy Brudnak; Ralph E.J. Boerner

    2008-01-01

    Prescribed fire and mechanical treatments were tested at the two hardwood sites of the National Fire and Fire Surrogate Study (southern and central Appalachian regions) for impacts to stand structure. After two fires and one mechanical treatment, no treatment or treatment combination restored stand structure to historical levels. Burning alone had little impact on...

  1. Woodland salamander and small mammal responses to alternative silvicultural practices in the Southern Appalachians of North Carolina

    Treesearch

    W. Mark Ford; Michael A. Menzel; Timothy S. McCay; Jonathan W. Gassett; Joshua Laerm

    2000-01-01

    The effects of 2 years post-treatment of group selection and 2-aged timber harvests on woodland salamanders and mammals were assessed on stands in high elevation, southern Appalachian northern red oak (Quercus rubra)-flame azalea (Rhododendron calendulaceum) communities, in the Nantahala National Forest. We collected 4 salamander...

  2. The Grenville orogeny in the Llano Uplift, Texas: A record of collision and contraction along the southern margin of North America

    SciTech Connect

    Reese, J.F. . Dept. of Geological Sciences)

    1993-02-01

    Precambrian metamorphic rocks in the SE Llano Uplift record NE-directed ductile thrusting and regional-scale polyphase folding. This deformation is in response to Grenville-age shortening and crustal thickening associated with the collision of a south-lying tectonic block with the southern margin of North America. In the SE Llano Uplift, the most intense and pervasive deformational event, D2, is characterized in the Packsaddle Schist (PS) and Valley Spring Gneiss (VSG) by SSE-plunging, NE-verging isoclinal folds (F2) with an associated SW-dipping axial planar metamorphic layering (S2), and SW-dipping mylonite zones with kinematic indicators showing top-to-the-NE motion. In the Red Mountain and augen-bearing Big Branch gneisses, D2 structures are SW-dipping mylonite zones parallel to S2, and a SW-plunging stretching lineation. Taken together, this suite of structures indicates tectonic transport was to the NE, perpendicular to the NW trending regional structural and metamorphic grain. D2 structures were reoriented by at least two later phases of folding. Timing of all ductile deformation in the SE Llano Uplift is constrained from post-1,215 Ma (deformed PS) to pre-1,098 Ma (undeformed melarhyolite dike). From south to north, metatonalitic, arc-derived Big Branch Gneiss ([approximately] 1,303 Ma) and older mafic schist country rock, previously interpreted as possible ophiolitic melange, structurally overlie much younger, lithologically heterogeneous PS units (1,248-1,215 Ma), previously considered as arc flank deposits. In turn, the PS has been tectonically emplaced above the predominantly felsic VSG (1,270-1,232 Ma). The presence of older zircons in the VSG, of similar age ([approximately]1360 Ma) to Western Granite-Rhyolite Terrane rocks to the north, suggests that the VSG formed in a settling proximal to North America.

  3. Temporal occurrence and community structure of helminth parasites in southern leopard frogs, Rana sphenocephala, from north central Oklahoma.

    PubMed

    Vhora, M Suhail; Bolek, Matthew G

    2015-03-01

    Currently, little information is available about the temporal recruitment of helminth communities in amphibian hosts. We examined the helminth community structure and temporal recruitment of helminth parasites in southern leopard frogs, Rana sphenocephala. Specifically, we were interested in how host life history such as habitat, age and/or size, diet, sex, and temporal variation in abiotic factors (precipitation and temperature) were important in determining monthly infection patterns of helminth populations and communities in southern leopard frogs. From May to September 2011, 74 southern leopard frogs were collected from Teal Ridge in Stillwater Payne County, OK, USA. Sixty-nine (93 %) of 74 frogs were infected with 1 or more helminth species. During our collecting period, the average monthly temperature was lowest in May and highest in July, and monthly precipitation was highest in May and lowest during the first week of September. The component community consisted of 11 species of helminth, including 1 larval and 1 adult cestode, 2 larval and 3 adult trematodes, and 1 juvenile and 3 adult nematodes. Of the 1790 helminths recovered, 51 % (911) were nematodes, 47 % (842) were cestodes, and 2 % (37) were trematodes. There were significant differences in the total abundance and mean species richness of helminths acquired by skin contact or through frog diet in monthly component communities of southern leopard frogs. A positive correlation existed for percentage of all helminths acquired by skin contact and monthly precipitation (r = 0.94, P < 0.01). Conversely, a negative correlation existed for monthly precipitation and percentage of helminths acquired by diet (r = -0.94, P < 0.01). Our results indicate that abiotic conditions such as precipitation have a major influence on the avenues for and constraints on the transmission of helminths with life cycles associated with water/moisture or terrestrial intermediate/paratenic hosts and are important in structuring

  4. Cost assessment and ecological effectiveness of nutrient reduction options for mitigating Phaeocystis colony blooms in the Southern North Sea: an integrated modeling approach.

    PubMed

    Lancelot, Christiane; Thieu, Vincent; Polard, Audrey; Garnier, Josette; Billen, Gilles; Hecq, Walter; Gypens, Nathalie

    2011-05-01

    Nutrient reduction measures have been already taken by wealthier countries to decrease nutrient loads to coastal waters, in most cases however, prior to having properly assessed their ecological effectiveness and their economic costs. In this paper we describe an original integrated impact assessment methodology to estimate the direct cost and the ecological performance of realistic nutrient reduction options to be applied in the Southern North Sea watershed to decrease eutrophication, visible as Phaeocystis blooms and foam deposits on the beaches. The mathematical tool couples the idealized biogeochemical GIS-based model of the river system (SENEQUE-RIVERSTRAHLER) implemented in the Eastern Channel/Southern North Sea watershed to the biogeochemical MIRO model describing Phaeocystis blooms in the marine domain. Model simulations explore how nutrient reduction options regarding diffuse and/or point sources in the watershed would affect the Phaeocystis colony spreading in the coastal area. The reference and prospective simulations are performed for the year 2000 characterized by mean meteorological conditions, and nutrient reduction scenarios include and compare upgrading of wastewater treatment plants and changes in agricultural practices including an idealized shift towards organic farming. A direct cost assessment is performed for each realistic nutrient reduction scenario. Further the reduction obtained for Phaeocystis blooms is assessed by comparison with ecological indicators (bloom magnitude and duration) and the cost for reducing foam events on the beaches is estimated. Uncertainty brought by the added effect of meteorological conditions (rainfall) on coastal eutrophication is discussed. It is concluded that the reduction obtained by implementing realistic environmental measures on the short-term is costly and insufficient to restore well-balanced nutrient conditions in the coastal area while the replacement of conventional agriculture by organic farming

  5. Environmental significance of 13C/ 12C and 18O/ 16O ratios of modern land-snail shells from the southern great plains of North America

    NASA Astrophysics Data System (ADS)

    Balakrishnan, Meena; Yapp, Crayton J.; Theler, James L.; Carter, Brian J.; Wyckoff, Don G.

    2005-01-01

    13C/ 12C and 18O/ 16O ratios of aragonite shells of modern land snails from the southern Great Plains of North America were measured for samples from twelve localities in a narrow east-west corridor that extended from the Flint Hills in North Central Oklahoma to the foothills of the Sangre de Cristo Mountains in Northern New Mexico, USA. Across the study area, shell δ 18O values (PDB scale) ranged from -4.1‰ to 1.2‰, while δ 13C values ranged from -13.2‰ to 0.0‰. δ 18O values of the shell aragonite were predicted with a published, steady state, evaporative flux balance model. The predicted values differed (with one exception) by less than 1‰ from locality averages of measured δ 18O values. This similarity suggests that relative humidity at the time of snail activity is an important control on the δ 18O values of the aragonite and emphasizes the seasonal nature of the climatic information preserved in the shells. Correlated δ 13C values of coexisting Vallonia and Gastrocopta suggest similar feeding habits and imply that these genera can provide information on variations in southern Great Plains plant ecology. Although there is considerable scatter, multispecies, transect average δ 13C values of the modern aragonite shells are related to variations in the type of photosynthesis (i.e., C 3, C 4) in the local plant communities. The results of this study emphasize the desirability of obtaining isotope ratios representing averages of many shells in a locale to reduce possible biases associated with local variations among individuals, species, etc., and thus better represent the "neighborhood" scale temporal and/or spatial environmental variations of interest in studies of modern and ancient systems.

  6. Genetic separation of southern and northern soybean breeding programs in North America and their associated allelic variation at four maturity loci.

    PubMed

    Wolfgang, Goettel; An, Yong-Qiang Charles

    2017-01-01

    North American soybean breeders have successfully developed a large number of elite cultivars with diverse maturity groups (MG) from a small number of ancestral landraces. To understand molecular and genetic basis underlying the large variation in their maturity and flowering times, we integrated pedigree and maturity data of 166 cultivars representing North American soybean breeding. Network analysis and visualization of their pedigree relationships revealed a clear separation of southern and northern soybean breeding programs, suggesting that little genetic exchange occurred between northern (MG 0-IV) and southern cultivars (MG V-VIII). We also analyzed the transcript sequence and expression levels of four major maturity genes (E1 to E4) and revealed their allelic variants in 75 major ancestral landraces and milestone cultivars. We observed that e1-as was the predominant e mutant allele in northern genotypes, followed by e2 and e3. There was no allelic variation at E4. Transcript accumulation of the e2 mutant allele was significantly reduced, which might be caused by its premature stop codon triggering the nonsense-mediated mRNA decay pathway. The large DNA deletion generating the e3 mutant allele also created a gene fusion transcript. The e alleles found in milestone cultivars were traced through pedigrees to their ancestral landraces and geographic origins. Our analysis revealed an approximate correlation between dysfunctional alleles and maturity groups for most of the 75 cultivars. However, single e mutant alleles and their combinations were not sufficient to fully explain their maturity diversity, suggesting that additional genes/alleles are likely involved in regulating maturity time.

  7. Phased occupation and retreat of the last British-Irish Ice Sheet in the southern North Sea; geomorphic and seismostratigraphic evidence of a dynamic ice lobe

    NASA Astrophysics Data System (ADS)

    Dove, Dayton; Evans, David J. A.; Lee, Jonathan R.; Roberts, David H.; Tappin, David R.; Mellett, Claire L.; Long, David; Callard, S. Louise

    2017-05-01

    Along the terrestrial margin of the southern North Sea, previous studies of the MIS 2 glaciation impacting eastern Britain have played a significant role in the development of principles relating to ice sheet dynamics (e.g. deformable beds), and the practice of reconstructing the style, timing, and spatial configuration of palaeo-ice sheets. These detailed terrestrially-based findings have however relied on observations made from only the outer edges of the former ice mass, as the North Sea Lobe (NSL) of the British-Irish Ice Sheet (BIIS) occupied an area that is now almost entirely submarine (c.21-15 ka). Compounded by the fact that marine-acquired data have been primarily of insufficient quality and density, the configuration and behaviour of the last BIIS in the southern North Sea remains surprisingly poorly constrained. This paper presents analysis of a new, integrated set of extensive seabed geomorphological and seismo-stratigraphic observations that both advances the principles developed previously onshore (e.g. multiple advance and retreat cycles), and provides a more detailed and accurate reconstruction of the BIIS at its southern-most extent in the North Sea. A new bathymetry compilation of the region reveals a series of broad sedimentary wedges and associated moraines that represent several terminal positions of the NSL. These former still-stand ice margins (1-4) are also found to relate to newly-identified architectural patterns (shallow stacked sedimentary wedges) in the region's seismic stratigraphy (previously mapped singularly as the Bolders Bank Formation). With ground-truthing constraint provided by sediment cores, these wedges are interpreted as sub-marginal till wedges, formed by complex subglacial accretionary processes that resulted in till thickening towards the former ice-sheet margins. The newly sub-divided shallow seismic stratigraphy (at least five units) also provides an indication of the relative event chronology of the NSL. While there

  8. Tectonostratigraphic evolution of the basins on the southern branch of the North Anatolian Fault System in the SE Marmara Region, Turkey

    NASA Astrophysics Data System (ADS)

    Doğan, Bülent; Tüysüz, Okan; Şanlı, Füsun Balık

    2015-03-01

    The lithostratigraphy of the Mekece-Iznik Corridor, the Geyve-Pamukova, and the Iznik basins on the southern branch of the North Anatolian Fault System (NAFS-SB) was investigated in detail. The intra-basin deposits carried by Sakarya River and the drainage systems in the northern and southern elevated blocks of the Iznik and Geyve-Pamukova Basins have been classified based on their lithofacies characteristics. The Geyve-Pamukova basin, which has developed with a NNE-SSW-trending transtensional strain, was formed as a lazy Z-shaped and releasing bend or pure strike-slip, pull-apart basin that is related to simple-shear, right-lateral strike-slip faulting. The Iznik basin was formed by a right-lateral strike-slip faulting kinematics and NNE-SSW-trending transtension as a result of the step-over of the northeast-trending Dırazali fault from the southern edge to the NW-trending Gürle fault, and the western step-over of this fault to the E-W-trending Umurbey fault. This strike-slip setting is also supported by the NW-SE-trending right-lateral oblique normal Orhangazi fault on the northern edge of the basin. According to this, the Iznik basin can be described as a more advanced stage of a large-scale, pull-apart basin compared with a lazy Z-shaped and releasing bend or transtensional strain. Furthermore, it is defined as the former stage of an extreme or rhomboid-type transtensional pull-apart basin.

  9. Late Cretaceous-Oligocene magmatic record in southern Mexico: The case for a temporal slab window along the evolving Caribbean-North America-Farallon triple boundary

    NASA Astrophysics Data System (ADS)

    Ferrari, Luca; Bergomi, Maria; Martini, Michelangelo; Tunesi, Annalisa; Orozco-Esquivel, Teresa; López-Martínez, Margarita

    2014-09-01

    Continental magmatism in southern Mexico is expected to record the eastward displacement of the Farallon-North America-Caribbean triple junction. However, a trench-transversal belt of magmatism in the central western Guerrero State does not fit into a regular pattern of arc migration and reorientation following the formation of the WSW trending Acapulco trench in the Cenozoic. We revised the magmatic pattern of southern Mexico using an updated database and new laser ablation inductively coupled plasma-mass spectrometry sensitive high-resolution ion microprobe, Ar-Ar ages, and geochemical and geologic data for the coastal part of the anomalous Guerrero belt. Our data reveal a persistent magmatic activity between 75 and 35 Ma, with a changing character at the Paleocene-Eocene boundary (circa 56 Ma). Late Cretaceous-Paleocene granitoids have an adakitic signature imprinted by stable garnet in the source and show no plagioclase fractionation, indicative of wet and oxidized magmas. Eocene rocks consist of an almost bimodal suite of plutonic bodies covered by a succession of mafic lavas. Granitic plutons show plagioclase fractionation and flat middle rare earth element-heavy rare earth element; gabbros have a tholeiitic character, indicative of dryer and more reduced magmas. They appear later and were emplaced at shallow depth in an extensional sedimentary basin. We interpret the magmatic record of the Guerrero belt as the response to two concurrent processes: (1) a temporal window in the Farallon slab induced by the concurrent subduction along the two noncollinear trench segments of southern Mexico (WNW trending) and of the Chortís block (NNW trending) and (2) a scissor-like transtensional rifting associated to counterclockwise rotation and eastward motion of the Chortís block.

  10. Molecular evolution of southern North American Cyprinidae (Actinopterygii), with the description of the new genus Tampichthys from central Mexico.

    PubMed

    Schönhuth, Susana; Doadrio, Ignacio; Dominguez-Dominguez, Omar; Hillis, David M; Mayden, Richard L

    2008-05-01

    Most of the recognized species of the genus Dionda inhabit drainages of the Gulf of Mexico from central Mexico to central Texas, USA, and have been considered a monophyletic group based on morphological, osteological, and allozyme investigations. Phylogenetic relationships of 15 species of Dionda and 34 species from closely related genera were inferred from one mitochondrial (cytb) and three nuclear gene sequences (S7, Rhodopsin, Rag1) totaling 4487 nucleotides. Separate analyses of all four genes yield congruent phylogenies; however the 15 putative species of Dionda evaluated were never recovered as a monophyletic group when species from nine related genera were included in the analyses. Among the ingroup taxa, one well-supported and highly divergent clade is consistently recognized and consists of six recognized and three undescribed northern species currently recognized in the genus Dionda. These nine species inhabit present or past tributaries of the Rio Grande basin of northern Mexico and southern USA, and were recovered as a basal clade in all analyses. Another large, also strongly supported clade, consisting of seven genera, include five southern recognized species currently in the genus Dionda, forming the sister group to the Codoma clade. These five species comprise the "Southern Dionda clade" and inhabit headwaters of the Pánuco-Tamesí drainage and some adjacent coastal rivers in the Tampico Embayment. The consistent and repeated identification of eight different clades recovered in most of the separate gene analyses strongly supports a division of the non-natural genus Dionda. A new genus, Tampichthys, is proposed for the clade of species endemic to east-central Mexico and formerly in Dionda. Tampichthys and the putative monotypic genus Codoma are more related to Mexican species of the genera Cyprinella and Notropis than to other species referred to Dionda sensu stricto.

  11. Review article. Studying climate effects on ecology through the use of climate indices: the North Atlantic Oscillation, El Niño Southern Oscillation and beyond.

    PubMed Central

    Stenseth, Nils Chr; Ottersen, Geir; Hurrell, James W; Mysterud, Atle; Lima, Mauricio; Chan, Kung-Sik; Yoccoz, Nigel G; Adlandsvik, Bjørn

    2003-01-01

    Whereas the El Niño Southern Oscillation (ENSO) affects weather and climate variability worldwide, the North Atlantic Oscillation (NAO) represents the dominant climate pattern in the North Atlantic region. Both climate systems have been demonstrated to considerably influence ecological processes. Several other large-scale climate patterns also exist. Although less well known outside the field of climatology, these patterns are also likely to be of ecological interest. We provide an overview of these climate patterns within the context of the ecological effects of climate variability. The application of climate indices by definition reduces complex space and time variability into simple measures, 'packages of weather'. The disadvantages of using global climate indices are all related to the fact that another level of problems are added to the ecology-climate interface, namely the link between global climate indices and local climate. We identify issues related to: (i) spatial variation; (ii) seasonality; (iii) non-stationarity; (iv) nonlinearity; and (v) lack of correlation in the relationship between global and local climate. The main advantages of using global climate indices are: (i) biological effects may be related more strongly to global indices than to any single local climate variable; (ii) it helps to avoid problems of model selection; (iii) it opens the possibility for ecologists to make predictions; and (iv) they are typically readily available on Internet. PMID:14561270

  12. Where are the polyps? Molecular identification, distribution and population differentiation of Aurelia aurita jellyfish polyps in the southern North Sea area.

    PubMed

    van Walraven, Lodewijk; Driessen, Floor; van Bleijswijk, Judith; Bol, Anneke; Luttikhuizen, Pieternella C; Coolen, Joop W P; Bos, Oscar G; Gittenberger, Adriaan; Schrieken, Niels; Langenberg, Victor T; van der Veer, Henk W

    For many species of metagenic jellyfish the location of the benthic polyps is unknown. To gain insight in the distribution, species composition and population structure of scyphozoan jellyfish polyps in the southern North Sea area, polyp samples were collected from natural and artificial substrates (settling plates, marina floats and wrecks) at ten inshore locations in the Netherlands, seven offshore locations in the North Sea and in the Gullmar Fjord in Sweden. Polyps were identified to species level by sequencing both a fragment of 18S rDNA and a fragment of mitochondrial COI, and comparing these sequences to reference sequences available in GenBank and to newly obtained sequences from medusae collected in the area. All polyps sequenced did belong to Aurelia aurita. For this species, molecular diversity in mitochondrial COI was high, with 50 haplotypes among 183 polyps. Population differentiation was detected between the Dogger Bank and other-more coastal-locations, indicating extremely low connectivity. No significant differences were found between coastal samples. The location of polyps of Cyanea capillata, Cyanea lamarckii, Chrysaora hysoscella and Rhizostoma octopus in the study area remains unresolved.

  13. Review article. Studying climate effects on ecology through the use of climate indices: the North Atlantic Oscillation, El Niño Southern Oscillation and beyond.

    PubMed

    Stenseth, Nils Chr; Ottersen, Geir; Hurrell, James W; Mysterud, Atle; Lima, Mauricio; Chan, Kung-Sik; Yoccoz, Nigel G; Adlandsvik, Bjørn

    2003-10-22

    Whereas the El Niño Southern Oscillation (ENSO) affects weather and climate variability worldwide, the North Atlantic Oscillation (NAO) represents the dominant climate pattern in the North Atlantic region. Both climate systems have been demonstrated to considerably influence ecological processes. Several other large-scale climate patterns also exist. Although less well known outside the field of climatology, these patterns are also likely to be of ecological interest. We provide an overview of these climate patterns within the context of the ecological effects of climate variability. The application of climate indices by definition reduces complex space and time variability into simple measures, 'packages of weather'. The disadvantages of using global climate indices are all related to the fact that another level of problems are added to the ecology-climate interface, namely the link between global climate indices and local climate. We identify issues related to: (i) spatial variation; (ii) seasonality; (iii) non-stationarity; (iv) nonlinearity; and (v) lack of correlation in the relationship between global and local climate. The main advantages of using global climate indices are: (i) biological effects may be related more strongly to global indices than to any single local climate variable; (ii) it helps to avoid problems of model selection; (iii) it opens the possibility for ecologists to make predictions; and (iv) they are typically readily available on Internet.

  14. Modeling the interaction between sedimentary organic carbon and infaunal macrobenthos and their temporal (1980-2000) variation in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Wenyan; Daewel, Ute; Schrum, Corinna; Wirtz, Kai

    2017-04-01

    The mutual dependency between sedimentary total organic carbon (TOC) and benthic macrofauna is here for the first time quantified by a mechanistic model. The model describes (i) the vertical distribution of infaunal biomass resulting from a trade-off between nutritional benefit (quantity and quality of TOC) and the costs of burial (respiration), and (ii) the variable distribution of TOC being in turn shaped by bioturbation of local macrobenthos. In contrast to state-of-the-art diagenetic models, our approach resolves variations of bioturbation both in space and time, which depend on the macrobenthic community structure and biomass. Our implementation of the dynamic interaction between sedimentary organic carbon and infaunal macrobenthos is able to capture a real-time benthic response to both depositional and erosional events and provides improved estimates of the material exchange flux at the sediment-water interface. Applications to literature data for the North Sea demonstrate the robustness and accuracy of the model and its potential as an analysis tool for the status of TOC as well as benthic infauna in marine sediments. The model was coupled to two different 3D hydrodynamic-ecological models (ECOSMO and MOSSCO for 10 x 10 and 1 x 1 km setups, respectively) to evaluate the robustness of the estimates with respect to variable forcings on different spatial scales. Hindcast simulations of the benthic status in the southern North Sea from 1980 to 2000 indicate a relatively stable pattern at large temporal and spatial scales but significant variations at small scales.

  15. Activity on the multi-stranded Central Branch of the North Anatolian Fault along the southern shelf of the Marmara Sea, Turkey

    NASA Astrophysics Data System (ADS)

    Okay, S.; Sorlien, C. C.; Cifci, G.; Cormier, M. H.; Dondurur, D.; Steckler, M. S.; Barin, B.; Seeber, L.

    2014-12-01

    The North Anatolian Fault (NAF), a major continental transform boundary, splays westward into three branches in the Sea of Marmara region of NW Turkey. The main northern branch passes only ~20 km from Istanbul and has been the subject of intense investigation, The central branch enters the sea of Marmara in Gemlik Bay and extends westeward along the southern shelf of the Sea of Marmara. However, its detailed offshore geometry as well as its level of seismic activity have remained controversial. Under the SoMAR Project, two geophysical cruises were carried out in 2013 and 2014 to map the major sedimentary basins and shallow fault patterns of the southern shelf of the Marmara Sea. Including our 2008 and 2010 acquisition, we acquired 4,430 km of high-resolution multichannel seismic, sparker, multibeam bathymetric and CHIRP data. We used the new data to correlate our published late Quaternary stratigraphic age model across the outer shelf, and a ~1/4 Ma horizon across the Inner Shelf, thus providing a chronology that can be applied to the tectonic history of the central branch. As it exits Gemlik Bay, the central branch itself diverges westward into strands in a fan pattern. A half dozen southern strands strike WSW and W, with one continuing onland near the Kocasu River delta between Bandırma and Mudanya, and others dying out offshore. The northern strand strikes WNW and splays again into the İmrali Ridge Fault and the Imrali Fault across respectively the mid-shelf and the shelf break. A middle fault, the Kapidag fault, is present between Kapidag Peninsula and Marmara Island. Most of the faults increase their vertical component with depth, suggesting activity during Pliocene through Holocene time. The Kapidag fault and Imrali Ridge fault each exhibit between 1 and 2 km of vertical separation of acoustic basement. Late Quaternary rates of vertical separation on these faults can accumulate the total vertical component after Miocene time. Thus, steady-state activity is

  16. Ice core sulfur and methanesulfonic acid (MSA) records from southern Greenland document North American and European air pollution and suggest a decline in regional biogenic sulfur emissions.

    NASA Astrophysics Data System (ADS)

    Pasteris, D. R.; McConnell, J. R.; Burkhart, J. F.; Saltzman, E. S.

    2014-12-01

    Sulfate aerosols have an important cooling effect on the Earth because they scatter sunlight back to space and form cloud condensation nuclei. However, understanding of the atmospheric sulfur cycle is incomplete, leading to uncertainty in the assessment of past, present and future climate forcing. Here we use annually resolved observations of sulfur and methanesulfonic acid (MSA) concentration in an array of precisely dated Southern Greenland ice cores to assess the history of sulfur pollution emitted from North America and Europe and the history of biogenic sulfate aerosol derived from the North Atlantic Ocean over the last 250 years. The ice core sulfur time series is found to closely track sulfur concentrations in North American and European precipitation since records began in 1965, and also closely tracks estimated sulfur emissions since 1850 within the air mass source region as determined by back trajectory analysis. However, a decline to near-preindustrial sulfur concentrations in the ice cores after 1995 that is not so extensive in the source region emissions indicates that there has been a change in sulfur cycling over the last 150 years. The ice core MSA time series shows a decline of 60% since the 1860s, and is well correlated with declining sea ice concentrations around Greenland, suggesting that the phytoplankton source of biogenic sulfur has declined due to a loss of marginal sea ice zone habitat. Incorporating the implied decrease in biogenic sulfur in our analysis improves the match between the ice core sulfur record and the source region emissions throughout the last 150 years, and solves the problem of the recent return to near-preindustrial levels in the Greenland ice. These findings indicate that the transport efficiency of sulfur air pollution has been relatively stable through the industrial era and that biogenic sulfur emissions in the region have declined.

  17. Palynostratigraphy of Permian succession in the Mand-Raigarh Coalfield, Chhattisgarh, India and phytogeographical provincialism

    NASA Astrophysics Data System (ADS)

    Murthy, Srikanta; Ram-Awatar; Gautam, Saurabh

    2014-12-01

    Palynofloras have been recorded from the Barakar Formation in the Borehole MBKW-3, Barpali-Karmitikra Block, Mand-Raigarh Coalfield, Chhattisgarh. Three distinct palynoassemblages have been identified and referred to the following palynoassemblage zones - Gondisporites raniganjensis (Latest Permian); Faunipollenites varius (latest Early Permian), and Scheuringipollenites barakarensis (late Early Permian). It is inferred that these deposits contain the representative palynoassamblages of Early to Late Permian in age. The First Appearance Datum (FAD)s of Arcuatipollenites pellucidus, A. ovatus, Guttulapollenites hannonicus, Lundbladispora microconata, Alisporites opii, Klausipollenites sp., and Goubinispora indica (at 41.95, 45.90, 98.35 m depth), indicate the closing phase of Permian, as these elements are the key species that mark a transition from Permian to the Lower Triassic. An attempt has been made here to reconstruct the phytogeographical provincialism on the basis of Guttulapollenites recorded in this basin.

  18. Assessment of trace metal toxicity in soils of Raniganj Coalfield, India.

    PubMed

    Das, Supriyo Kumar; Chakrapani, Govind J

    2011-06-01

    Soil, rock and water samples were collected from India's oldest coalfield Raniganj to investigate trace metal contamination from mining activity. Our data reveal that trace metal concentration in soil samples lies above the average world soil composition; especially, Cr, Cu, Ni and Zn concentrations exceed the maximum allowable concentration proposed by the European Commission for agricultural soils. In particular, Cr, Cu and Ni exceed the ecotoxicological limit, and Ni exceeds the typical value for cultivated soils. Mineral dissolution from overburden material and high adsorption capacity of laterite soil are responsible for the elevated concentrations. This is evident from enrichment factor (E (f)), geoaccumulation index (I (geo)) and metal pollution index values. Sediment quality guideline index indicates toxicity to local biota although enrichment index suggests no threat from consuming crops cultivated in the contaminated soil.

  19. Disability and the Family in South Wales Coalfield Society, c.1920-1939.

    PubMed

    Curtis, Ben; Thompson, Steven

    2017-01-02

    This article utilises the south Wales coalfield in the interwar period as a case study to illustrate the applicability of two sociological theories - family systems theory and the social ecology of the family - to impairment in the past. It demonstrates that a theoretically-informed approach can help to situate impairment in its particular contexts, most especially the family and the community, and give a better sense of the lived experience of disability. It also demonstrates the complexity of the experience of disability as the family and economic circumstances of each impaired individual varied and led to different forms of care-giving or the utilisation of different sources of support. The article also sheds further light on the ubiquity of disability as many families included a number of individuals with different impairments and this too had consequences for experiences and coping strategies.

  20. Disability and the Family in South Wales Coalfield Society, c.1920–1939

    PubMed Central

    Curtis, Ben; Thompson, Steven

    2017-01-01

    This article utilises the south Wales coalfield in the interwar period as a case study to illustrate the applicability of two sociological theories – family systems theory and the social ecology of the family – to impairment in the past. It demonstrates that a theoretically-informed approach can help to situate impairment in its particular contexts, most especially the family and the community, and give a better sense of the lived experience of disability. It also demonstrates the complexity of the experience of disability as the family and economic circumstances of each impaired individual varied and led to different forms of care-giving or the utilisation of different sources of support. The article also sheds further light on the ubiquity of disability as many families included a number of individuals with different impairments and this too had consequences for experiences and coping strategies. PMID:28706465

  1. Flow path of the 1993 Hokkaido-Nansei-oki earthquake seismoturbidite, southern margin of the Japan sea north basin, inferred from anisotropy of magnetic susceptibility

    NASA Astrophysics Data System (ADS)

    Abdeldayem, A. L.; Ikehara, K.; Yamazaki, T.

    2004-04-01

    A magnetic fabric analysis has been carried out on standard cube samples from one gravity and three multiple cores extracted from the Shiribeshi trough and Okushiri basin in the southern margin of the Japan sea north basin. It is aimed at tracing the flow path of turbidites that are assumed to have deposited in response to the 1993 Hokkaido-Nansei-oki earthquake. Magnetic remanence was used for reorientation to the geographic coordinates. Magnetomineralogical investigations including low-temperature magnetometry, magnetic hysteresis loops and isothermal remanent magnetization (IRM) acquisition experiments indicate that pseudo-single domain to multidomain magnetite is the principal magnetic carrier and is, therefore, capable of providing reliable anisotropy of magnetic susceptibility (AMS) palaeocurrent direction estimates. A well-developed near-horizontal magnetic foliation and minimum susceptibility axes lying close to vertical are recorded at all sites reflecting an original depositional fabric. Clearly defined magnetic lineation was observed at all sites and is considered to reflect the palaeocurrent direction. Down-core changes of susceptibility and key AMS parameters show good correspondence to occurrences of turbidite layers marking the increase of input of influx materials. In agreement with results from recent marine surveys and IZANAGI side-scan sonar images, an NNE transportation trend has been estimated for sediments at sites from the Shiribeshi trough with a possible depositing path initiating from the slope bounding the south and southeastern margin down to the trough floor. Similarly, a SSE palaeocurrent direction has been estimated for sediments from the Okushiri basin with evidence for a relatively strong transporting current flowing through the canyons along the steep slope bounding the north and northeastern margins of the basin. The present results agree with the view that slope failure is the most probable mechanism for the down-slope transport

  2. Late Ordovician (post-Sardic) rifting branches in the North Gondwanan Montagne Noire and Mouthoumet massifs of southern France

    NASA Astrophysics Data System (ADS)

    Javier Álvaro, J.; Colmenar, Jorge; Monceret, Eric; Pouclet, André; Vizcaïno, Daniel

    2016-06-01

    Upper Ordovician-Lower Devonian rocks of the Cabrières klippes (southern Montagne Noire) and the Mouthoumet massif in southern France rest paraconformably or with angular discordance on Cambrian-Lower Ordovician strata. Neither Middle-Ordovician volcanism nor associated metamorphism is recorded, and the subsequent Middle-Ordovician stratigraphic gap is related to the Sardic phase. Upper Ordovician sedimentation started in the rifting branches of Cabrières and Mouthoumet with deposition of basaltic lava flows and lahar deposits (Roque de Bandies and Villerouge formations) of continental tholeiite signature (CT), indicative of continental fracturing. The infill of both rifting branches followed with the onset of (1) Katian (Ka1-Ka2) conglomerates and sandstones (Glauzy and Gascagne formations), which have yielded a new brachiopod assemblage representative of the Svobodaina havliceki Community; (2) Katian (Ka2-Ka4) limestones, marlstones, and shales with carbonate nodules, reflecting development of bryozoan-echinoderm meadows with elements of the Nicolella Community (Gabian and Montjoi formations); and (3) the Hirnantian Marmairane Formation in the Mouthoumet massif that has yielded a rich and diverse fossil association representative of the pandemic Hirnantia Fauna. The sealing of the subaerial palaeorelief generated during the Sardic phase is related to Silurian and Early Devonian transgressions leading to onlapping patterns and the record of high-angle discordances.

  3. Selected hydrologic data, Kolob-Alton-Kaiparowits coal-fields area, south-central Utah

    USGS Publications Warehouse

    Plantz, Gerald G.

    1983-01-01

    The Kolob-Alton-Kaiparowits coal-field area (pi. 1) includes about 4,500 square miles in parts of the Colorado River Basin and the Great Basin. The area varies in altitude from less than 4,000 to more than 10,000 feet, and is comprised chiefly of plateaus, benches, and terraces that are dissected by deep, narrow canyons. Principal streams draining the area are the Virgin, Sevier, Escalante, and Paria Rivers, and Coal, Kanab, and Wahweap Creeks.Most of the data included in this report were collected by the U.S. Geological Survey from October 1980 to September 1982. They were collected as part of a hydrologic study in cooperation with the U.S. Bureau of Land Management to evaluate potential impacts of coal mining on the area's water resources. The results of that study are to be published in a separate report.Several earlier coal-related hydrologic studies have been made in the Alton and Kolob coal-fields area. Hydrologic data collected during those studies may be found in the following reports: Goode (1964, 1966), Sandberg (1979), and Cordova (1981). Data collected at the streamflow-gaging stations shown on plate 1 are published separately in annual reports of the U.S. Geological Survey. Information about the availability of these data is given in table 8.The writer extends thanks to Judy Steiger and Dave Darby (former employees of the U.S. Geological Survey) for their contribution to this report. Officials of the following companies and agencies also were helpful and cooperative in providing data: Utah Power & Light Co.; El Paso Natural Gas Co.; U.S. Bureau of Reclamation; and U.S. Bureau of Land Management.

  4. Geochemistry of rare earth elements in Permian coals from the Huaibei Coalfield, China

    USGS Publications Warehouse

    Zheng, Lingyun; Liu, Gaisheng; Chou, C.-L.; Qi, C.; Zhang, Y.

    2007-01-01

    The rare earth elements (REEs) in coals are important because of: (a) REE patterns can be an indicator of the nature of source rocks of the mineral matter as well as sedimentary environments; (b) REEs abundance in coal may have industrial-significance. In this study, a total of thirty-four samples of Permian coal, partings, roof, and floor were collected from the Huaibei Coalfield, Anhui Province, China. Abundances of rare earth elements (REEs) and other elements in the samples were determined by inductively coupled-plasma mass spectrometry (ICP-MS) and inductively coupled-plasma atomic emission spectrometry (ICP-AES). The results show that the REEs are enriched in coals in the Huaibei Coalfield as compared with Chinese and U.S. coals and the world coal average. Coals in the Lower Shihezi Formation (No. 7, 5, and 4 Coals) and Upper Shihezi Formation (No. 3) have higher REE abundances than the coals in Shanxi Formation (No. 10). Magmatic intrusion resulted in high enrichment of REEs concentrations in No. 5 and 7 Coals. The REE abundances are positively correlated with the ash content. The mineral matter in these coals is mainly made up of clay minerals and carbonates. The REEs are positively correlated with lithophile elements including Si, Al, Ti, Fe, and Na, which are mainly distributed in clay minerals, indicating that REEs are contained mainly in clay minerals. The REE abundances in coals normalized by the ash are higher than that in partings. REEs abundances of coals cannot be accounted for by the REE content in the mineral matter, and some REEs associated with organic matter in coals. ?? 2007 Elsevier Ltd. All rights reserved.

  5. Geochemistry of rare earth elements in Permian coals from the Huaibei Coalfield, China

    NASA Astrophysics Data System (ADS)

    Zheng, Liugen; Liu, Guijian; Chou, Chen-Lin; Qi, Cuicui; Zhang, Ying

    2007-10-01

    The rare earth elements (REEs) in coals are important because of: (a) REE patterns can be an indicator of the nature of source rocks of the mineral matter as well as sedimentary environments; (b) REEs abundance in coal may have industrial-significance. In this study, a total of thirty-four samples of Permian coal, partings, roof, and floor were collected from the Huaibei Coalfield, Anhui Province, China. Abundances of rare earth elements (REEs) and other elements in the samples were determined by inductively coupled-plasma mass spectrometry (ICP-MS) and inductively coupled-plasma atomic emission spectrometry (ICP-AES). The results show that the REEs are enriched in coals in the Huaibei Coalfield as compared with Chinese and U.S. coals and the world coal average. Coals in the Lower Shihezi Formation (No. 7, 5, and 4 Coals) and Upper Shihezi Formation (No. 3) have higher REE abundances than the coals in Shanxi Formation (No. 10). Magmatic intrusion resulted in high enrichment of REEs concentrations in No. 5 and 7 Coals. The REE abundances are positively correlated with the ash content. The mineral matter in these coals is mainly made up of clay minerals and carbonates. The REEs are positively correlated with lithophile elements including Si, Al, Ti, Fe, and Na, which are mainly distributed in clay minerals, indicating that REEs are contained mainly in clay minerals. The REE abundances in coals normalized by the ash are higher than that in partings. REEs abundances of coals cannot be accounted for by the REE content in the mineral matter, and some REEs associated with organic matter in coals.

  6. Mineralogy and geochemistry of the No. 6 Coal (Pennsylvanian) in the Junger Coalfield, Ordos Basin, China

    USGS Publications Warehouse

    Dai, S.; Ren, D.; Chou, C.-L.; Li, S.; Jiang, Y.

    2006-01-01

    This paper discusses the mineralogy and geochemistry of the No. 6 Coal (Pennsylvanian) in the Junger Coalfield, Ordos Basin, China. The results show that the vitrinite reflectance (0.58%) is lowest and the proportions of inertinite and liptinite (37.4% and 7.1%, respectively) in the No. 6 Coal of the Junger Coalfield are highest among all of the Late Paleozoic coals in the Ordos Basin. The No. 6 Coal may be divided vertically into four sections based on their mineral compositions and elemental concentrations. A high boehmite content (mean 6.1%) was identified in the No. 6 Coal. The minerals associated with the boehmite in the coal include goyazite, rutile, zircon, and Pb-bearing minerals (galena, clausthalite, and selenio-galena). The boehmite is derived from weathered and oxidized bauxite in the weathered crust of the underlying Benxi Formation (Pennsylvanian). A high Pb-bearing mineral content of samples ZG6-2 and ZG6-3 is likely of hydrothermal origin. The No. 6 coal is enriched in Ga (44.8 ??g/g), Se (8.2 ??g/g), Sr (423 ??g/g), Zr (234 ??g/g), REEs (193.3 ??g/g), Hg (0.35 ??g/g), Pb (35.7 ??g/ g), and Th (17.8 ??g/g). Gallium and Th in the No. 6 Coal mainly occur in boehmite, and the Pb-bearing selenide and sulfide minerals contribute not only to Se and Pb contents in the coal, but also probably to Hg content. A high Zr content is attributed to the presence of zircon, and Sr is related to goyazite. The REEs in the coal are supplied from the sediment-source region, and the REEs leached from the adjacent partings by groundwater. ?? 2005 Elsevier B.V. All rights reserved.

  7. Spatio-temporal spawning and larval dynamics of a zebra mussel (Dreissena polymorpha) population in a North Texas Reservoir: implications for invasions in the southern United States

    USGS Publications Warehouse

    Churchill, Christopher John

    2013-01-01

    Zebra mussels were first observed in Texas in 2009 in a reservoir (Lake Texoma) on the Texas-Oklahoma border. In 2012, an established population was found in a near-by reservoir, Ray Roberts Lake, and in June 2013, settled mussels were detected in a third north Texas reservoir, Lake Lewisville. An established population was detected in Belton Lake in September 2013. With the exception of Louisiana, these occurrences in Texas mark the current southern extent of the range of this species in the United States. Previous studies indicate that zebra mussel populations could be affected by environmental conditions, especially increased temperatures and extreme droughts, which are characteristic of surface waters of the southern and southwestern United States. Data collected during the first three years (2010–12) of a long-term monitoring program were analyzed to determine if spatio-temporal zebra mussel spawning and larval dynamics were related to physicochemical water properties in Lake Texoma. Reproductive output of the local population was significantly related to water temperature and lake elevation. Estimated mean date of first spawn in Lake Texoma was approximately 1.5 months earlier and peak veliger densities were observed two months earlier than in Lake Erie. Annual maximum veliger density declined significantly during the study period (p < 0.0001). A population crash occurred as a result of thermal stress and variability of lake elevation. In summer 2011, water temperatures peaked at 34.3°C and lake elevation declined to the lowest level recorded during the previous 18 years, which resulted in desiccation of substantial numbers of settled mussels in littoral zones. Veliger spatial distributions were associated with physicochemical stratification characteristics. Veligers were observed in the deepest oxygenated water after lake stratification, which occurred in late spring. Results of this study indicate environmental conditions can influence variability of

  8. Gradual Warming in the North Atlantic during D-O Events Synchronous with Antarctic and Southern Hemisphere Warmings

    NASA Astrophysics Data System (ADS)

    Rasmussen, T. L.; Thomsen, E.; Moros, M.

    2016-12-01

    The climate of the last glacial period was interrupted by about 25 rapid oscillations, called Dansgaard-Oeschger events. In the Greenland ice cores, the events consist of an abrupt warming to warm interstadial conditions followed by a more gradual return to cold stadial conditions. Similar abrupt warmings are seen in paleoceanographic proxies from the Nordic seas, and the shifts are apparently linked to perturbations in the ocean thermohaline circulation. The events also occur in the Antarctic ice cores, but the amplitudes here are smaller and the warmings are more gradual and initiated earlier than in the north. The out-of-phase relationship between the north and south is often referred to as the `Bipolar seesaw'. We have studied core SO2 from the Reykjanes Ridge in the central northernmost Atlantic. The results are compared with previously published records from the North Atlantic and correlated with the Greenland and Antarctic ice cores. By means of transfer function analysis and δ18O values from planktic and benthic foraminifera we show that surface and bottom water temperatures in SO2 increased gradually during the Greenland stadials to a maximum at the beginning of the interstadials. The warmings in SO2 follow the timing and gradual warmings observed in the Antarctic ice cores and they are clearly out of phase with the abrupt, delayed warmings over Greenland. Apparently, the surface and intermediate water over most of the Atlantic from the Antarctica to the Scotland-Greenland Ridge warmed and pressed northward at a time when the atmospheric temperatures over Greenland were at minimum and the convection in the Nordic seas stopped. The system appears to function more as a `push-and-pull' system than as a seesaw with a `pull' during the warm interstadials, when convection in the Nordic seas was active and a `push' during the cold stadials, when warm water from the south-central Atlantic pushed northward gradually warming the northernmost Atlantic and Nordic

  9. 50 CFR 226.219 - Critical habitat for the Southern Distinct Population Segment of North American Green Sturgeon...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Clallam County east of a line connecting Cape Flattery (48°23′10″ N./124°43′32″ W.), Tatoosh Island (48°23... and Island counties north and west of a line connecting Point Wilson (48°08′38″ N./122°45′07″ W.) and... (48°29′34″ N./122°42′07″ W.) and Lopez Island (48°28′43″ N./122°49′08″ W.). (2) Freshwater...

  10. Geomorphology and tectonics of uplifted coasts: New chronostratigraphical constraints for the Quaternary evolution of Tyrrhenian North Calabria (southern Italy)

    NASA Astrophysics Data System (ADS)

    Filocamo, F.; Romano, P.; Di Donato, V.; Esposito, P.; Mattei, M.; Porreca, M.; Robustelli, G.; Russo Ermolli, E.

    2009-04-01

    The Tyrrhenian coastal sector of North Calabria, stretching between Torre S. Nicola and the Lao river, belongs to the inner extensional sector of the Neogene Apennines thrust belt. It is characterised by a stair of Quaternary marine and fluvial terraces representing the geomorphic response to the interaction between the Quaternary sea level fluctuations and the regional trend of tectonic uplift experienced by the margins of the Tyrrhenian back-arc basin. Since the last century, several authors studied the North Calabria coasts, where the flight of terraces preserves significant marine and continental successions, and proposed several paleo-geomorphological and tectonic reconstructions. In this paper we present a new stratigraphic and morphostructural setting of the North Calabria coasts based on both chronostratigraphical constraints obtained from marine deposits and detailed geomorphological analysis. A ten order stair of marine terraces, stepping between 240 and 0 m a.s.l., was recognized and time-constrained by the age of the Fornaci S. Nicola marine succession which was ascribed by integrated paleoecological, biostratigraphical and paleomagentic analyses to the early Middle Pleistocene (MIS 19-15). In particular, the 240, 200 and 160 m a.s.l. high strandlines were ascribed to the Early Pleistocene and the ones between 100 and 15 m a.s.l. to the Middle Pleistocene. The total amount of the vertical motion experienced by the studied area was estimated, and evaluation of the average rates of uplift for the Middle and Late Pleistocene times were also given. Considering the elevation a.s.l. of the oldest terraces, a tectonic uplift of at least 240 m was calculated for the North Calabria coasts since the Early Pleistocene times, 100 m of which gained from the beginning of the Middle Pleistocene. On the other hand, the 8-m high Late Pleistocene strandlines display a negligible vertical displacement affecting the area during the last 130 ka. The entire staircase of

  11. Annual variations of biomass and photosynthesis in Zostera marina at its southern end of distribution in the North Pacific

    USGS Publications Warehouse

    Cabello-Pasini, Alejandro; Munoz-Salazar, R.; Ward, D.H.

    2003-01-01

    Density, biomass, morphology, phenology and photosynthetic characteristics of Zostera marina were related to continuous measurements of in situ irradiance, attenuation coefficient and temperature at three coastal lagoons in Baja California, Mexico. In situ irradiance was approximately two-fold lower at San Quintin Bay (SQ) than at Ojo de Liebre Lagoon (OL) and San Ignacio Lagoon (SI). As a consequence of the greater irradiance, plants at OL and SI were established 1 m deeper within the water column than those at SQ. At SQ, there was a four-fold variation in biomass of Z. marina caused by changes on shoot length and not shoot density, while at OL and SI biomass and shoot length did not fluctuate significantly throughout the year. Reproductive shoot density reached maximum values concomitantly with the greatest irradiance during spring-summer, however, the density was approximately three-fold greater at SQ than at the southern coastal lagoons. While irradiance levels were two-fold greater at the southern lagoons, in general, photosynthetic characteristics were similar among all three lagoons. The hours of light saturated photosynthesis, calculated from their photosynthetic characteristics and irradiance measurements, suggest that photosynthesis of shoots from OL and SI are saturated for more than 6 h per day throughout the year, while shoots from SQ are likely light limited during approximately 15% of the year. Consequently, an increase in attenuation coefficient values in the water column will likely decrease light availability to Z. marina plants at SQ, potentially decreasing their survival. ?? 2003 Elsevier Science B.V. All rights reserved.

  12. Seismic facies analysis of delta-plain coals from Camrose, Alberta, and lacustrine coals from Pictou coalfield, Nova Scotia

    SciTech Connect

    Lawton, D.C.

    1985-12-01

    Facies models of two coalfields in Canada have been developed through seismic facies analysis. Fluvial-deltaic Upper Cretaceous coals near Camrose, Alberta, are characterized by hummocky, subparallel, high-amplitude reflections that are laterally continuous over distances of several kilometers. Deposition in an extensive delta-plain swamp is inferred. Coals of Pennsylvanian age in the Pictou coalfield, Nova Scotia, occur in two distinct seismic facies. Parallel to subparallel, relatively continuous reflections are interpreted to define a basinal facies comprising thick coals and lacustrine sediments. Basinal margin facies contain a greater abundance of variable clastic sediments and are recognized by discontinuous, subparallel to chaotic reflections. Further improvements in stratigraphic analysis will require synthetic seismograms to analyze individual reflections in terms of the thickness and separation of seams, and to enable interseam multiples to be recognized. 9 figures, 2 tables.

  13. Southern Italy

    NASA Image and Video Library

    1973-06-22

    SL2-05-359 (22 June 1973) --- This rare cloud free view of southern Italy (41.0N, 16.0E) shows almost all of the famous `boot' configuration of the peninsula up to just north of Naples and Mount Vesuvius. The land mass of this historic peninsula contrasts sharply with the sparkling blue waters of the Mediterranean Sea. Photo credit: NASA

  14. The geology and petroleum potential of the North Afghan platform and adjacent areas (northern Afghanistan, with parts of southern Turkmenistan, Uzbekistan and Tajikistan)

    NASA Astrophysics Data System (ADS)

    Brookfield, Michael E.; Hashmat, Ajruddin

    2001-10-01

    platform began in the Miocene. Oil and gas traps are mainly in Upper Jurassic carbonates and Lower Cretaceous sandstones across the entire North Afghan block. Upper Jurassic carbonate traps, sealed by evaporites, occur mainly north of the southern limit of the Upper Jurassic salt. Lower Cretaceous traps consist of fine-grained continental sandstones, sealed by Aptian-Albian shales and siltstones. Upper Cretaceous-Palaeocene carbonates, sealed by Palaeogene shales are the main traps along the northern edge of the platform and in the Tajik basin. Almost all the traps are broad anticlines related to Neogene wrench faulting, in this respect, like similar traps along the San Andreas fault. Hydrocarbon sources are in the Mesozoic section. The Lower-Middle Jurassic continental coal-bearing beds provide about 75% of the hydrocarbons; the Callovian-Oxfordian provides about 10%; the Neocomian a meagre 1%, and the Aptian-Albian about 14%. The coal-bearing source rocks decrease very markedly in thickness southwards cross the North Afghan platform. Much of the hydrocarbon generation probably occurred during the Late Cretaceous-Paleogene and migrated to structural traps during Neogene deformation. Since no regional structural dip aids southward hydrocarbon migration, and since the traps are all structural and somewhat small, then there is little chance of very large petroleum fields on the platform. Nevertheless, further studies of the North Afghan platform should be rewarding because: (a) the traps of strike-slip belts are difficult to find without detailed exploration; (b) the troubles of the last 20 years mean that almost no exploration has been done; and, (c) conditions may soon become more favorable. There should be ample potential for oil, and particularly gas, discoveries especially in the northern and western parts of the North Afghan platform.

  15. Westward extension of the Devils River uplift Implications for the Paleozoic evolution of the southern margin of North America

    NASA Astrophysics Data System (ADS)

    Ewing, Thomas E.

    1985-06-01

    The Devils River uplift is inferred to continue westward into Trans-Pecos Texas. Both the known Devils River uplift and the Tascotal uplift are bounded on the north by east-west fault zones (Chalk Draw and Carta Valley fault zones) separating them from Late Pennsylvanian clastic foredeep basins (Marfa and Val Verde basins). The exposed, much-shortened Marathon thrust belt may have been emplaced in the earliest Permian by gravity gliding. Meager evidence suggests that the Devils River block represents a Cambrian or Infracambrian rift and that the uplift is an aulacogen. The early Cambrian continental margin probably continued southwest into Mexico but has been displaced by Mesozoic left-lateral movement.

  16. Transport of East Asian dust storms to the marginal seas of China and the southern North Pacific in spring 2010

    NASA Astrophysics Data System (ADS)

    Tan, Sai-Chun; Li, Jiawei; Che, Huizheng; Chen, Bin; Wang, Hong

    2017-01-01

    The transport of a super-severe dust storm that occurred in East Asia from 19 to 22 March 2010 has been well documented by both model simulations and surface observations. We investigated the transport of this severe dust storm and several other spring 2010 dust storms using model simulations, backward trajectories, and measurements from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. The model simulations indicated that the emission of dust in spring 2010 was about 35% higher than that in spring 2006 and was twice that of the 44-year average from 1960 to 2003. The dust emissions over two major source regions (western China and the Gobi Desert) in spring 2010 accounted for 86% of the total amount of dust. The simulated depositional flux over the two major source regions was c.2.7-9.0 times that over two marginal seas (the Yellow Sea and the East China Sea) and more than two magnitudes higher than that over the North Pacific Subtropical Gyre. The mean extinction coefficient observed by the CALIPSO satellite over the two source regions was c.1.3-3.7 times that over the two marginal seas and one magnitude higher than that over the North Pacific. This was consistent with the result from our model, suggesting that this model is able to capture the major features of dust storms. The vertical profiles recorded by the CALIPSO satellite indicated that the dust aerosol mainly floated from the ground to 13 km above ground level over the source regions and above the seas. A multiple dust layer appeared over the seas and the backward trajectories suggested that the dust aerosol in different layers may have been sourced from different regions.

  17. The application of the Intermittent SBAS (ISBAS) InSAR method to the South Wales Coalfield, UK

    NASA Astrophysics Data System (ADS)

    Bateson, Luke; Cigna, Francesca; Boon, David; Sowter, Andrew

    2015-02-01

    Satellite radar interferometry is a well-documented technique for the characterisation of ground motions over large spatial areas. However, the measurement density is often constrained by the land use, with best results obtained over urban and semi urban areas. We use an implementation of the Small Baseline Subset (SBAS) methodology, whereby areas exhibiting intermittent coherence are considered alongside those displaying full coherence, in the final result, to characterise the ground motion over the South Wales Coalfield, United Kingdom. 55 ERS-1/2 Synthetic Aperture Radar (SAR) C-band images for the period between 1992 and 1999 are processed using the ISBAS (Intermittent Small BAseline Subset) technique, which provides 3.4 times more targets, with associated measurements than a standard SBAS implementation. The dominant feature of the observed motions is a relatively large spatial area of uplift. Uplift rates are as much as 1 cm/yr. and are centred on the part of the coalfield which was most recently exploited. Geological interpretation reveals that this uplift is most likely a result of mine water rebound. Collieries in this part of the coalfield required a ground water to be pumped to enable safe coal extraction; following their closure pumping activity ceased allowing the water levels to return to equilibrium. The ISBAS technique offers significant improvements in measurement density ensuring an increase in detection of surface motions and enabling easier interpretation.

  18. The hercynian compressive then extensive tectonic of the north flank of the Montagne Noire (southern French Massif Central)

    NASA Astrophysics Data System (ADS)

    Turpaud, P.; Matte, P.

    2003-04-01

    The Montagne Noire, (southernmost edge of the Massif Central) is well known on its southern flank by low-grade spectacular hercynian nappes and southward recumbent folds. The northern flank, much less known is separated from the southern nappes by a large high grade metamorphic dome, the Axial Zone, which has been interpreted either as a purely extensive metamorphic core complex or as a compressive migmatitic antiform. The northern flank made of Lower Paleozoic epizonal sediments and granitic orthogneisses was previously interpreted as tectonic units separated by, NE-SW trending, southeastward verging thrusts. Our recent kinematic study shows a more complex structure and history: -- Some of the so-called southeastward thrusts (Brusque area) are in fact large, kilometre thick, ductile sinistral shear-zones with a southwestward thrust component (Guérangé-Lozes et Alsac, 1986), southward verging folds and slaty cleavage. That is the first major deformation in the Northern Montagne Noire and it is still undated. -- Closer to the Axial dome, in the Lacaune area, the most conspicuous structures are younger and related to large northeastward detachment with a LP/MT metamorphism. NE-SW trending lineations are here significant of a strong top to the NE shearing well expressed by fish-like biotites, synkinematic cordierites with helicitic inclusion trails, asymmetric boudinage and F2 northeastward drag folds. This spectacular detachment tectonic, which affects as well the whole northern flank of the granitic-gneissic Axial Zone, is dated by Ar39/Ar40 laser method on synkinematic micas at about 300--310 Ma. This event helped to the exhumation and denudation of the gneissic Axial Zone, just before the deposit of Stephanian limnic coal basins. The MT/BP metamophism is contemporaneous of the ductile detachment tectonic but some clues of gaps of metamorphism in the PT section indicate probably late normal faults with the same kinematics but posterior to the metamorphic climax

  19. Tectonic significance and geodynamic processes of large-scale Early Cretaceous granitoid magmatic events in the southern Great Xing'an Range, North China

    NASA Astrophysics Data System (ADS)

    Li, Shan; Chung, Sun-Lin; Wang, Tao; Wilde, Simon A.; Chu, Mei-Fei; Guo, Qian-Qian

    2017-04-01

    The origin and geodynamic evolution of peak Early Cretaceous magmatism in the southern Great Xing'an Range, North China, have long been controversial. Here we report new U-Pb zircon ages (141-129 Ma) of a suite of dioritic-granitic rocks from central Inner Mongolia, far from the sutures or plate boundaries of the Paleo-Pacific and Mongol-Okhotsk oceans, thus delineating an Early Cretaceous intracontinental magmatic province, which had a peak activity at 130-120 Ma. Dioritic suite including diorite, tonalite, and granodiorite shows variable zircon ɛHf(t) of +1.4 to + 11.8 and δ18O values of +5.7 to +6.9‰, while granitic suite consisting of monzogranite, syenogranite, and granite porphyry also records variable zircon ɛHf(t) of -0.9 to +15.0 and δ18O values of +6.3 to +8.1‰, suggesting crustal melting by preexisting crustal source with important recycled supracrustal components including fluids. Furthermore, these rocks show variable whole-rock δ7Li values (-0.6 to +12.1‰), indicating fluids played an important role in magma source. We propose a deep-sourced water-fluxed melting scenario by ancient hydrous slabs inherited from the Paleo-Asian Ocean that were trapped in the deep interior, thus releasing aqueous fluids to melt the lithospheric mantle and produce water-rich mafic magmas. These mafic magmas were underplated into crust where they promoted water-fluxed partial melting to generate the large-scale Early Cretaceous magmatism in the southern Great Xing'an Range. Such melting due to fluxing of aqueous fluids was probably operating as a widespread process responsible for the Early Cretaceous dramatically tectonomagmatic events and evolution of continental crust in NE Asia.

  20. Tectonic activity and stratigraphic history over the last 130-540 ka on the Southern Shelf of the Sea of Marmara, western North Anatolian Fault, Turkey

    NASA Astrophysics Data System (ADS)

    Smith, W. H.; Grall, C.; Sorlien, C. C.; Steckler, M. S.; Okay, S.; Cormier, M. H.; Seeber, L.; Cifci, G.; Dondurur, D.

    2016-12-01

    The submerged section of the North Anatolian Fault in the Sea of Marmara, which corresponds to the dextral plate boundary between Eurasia and Anatolia, poses strong hazard for earthquakes and subsequent submarine landslides and tsunamis in the vicinity of the highly populated region of Istanbul. Most of the right-lateral slip is accommodated by the Northern Branch of the North Anatolian Fault (NAF-N), which crosses the central part of the Sea of Marmara and is capable of an earthquake with a magnitude greater than 7. However, both the geology and the geodesy suggest that the NAF-N accommodates only 3/4 of the total slip between the plates. The deformation mechanisms for the rest of the strain (slip distributed on secondary faults, strain partitioning, and diffuse deformation) remains unexplained. Other fault systems, primarily south of the NAF-N, are shown to be important regarding the tectonic evolution of the Sea of Marmara. However, the activity of these peripheral fault systems as well as their relationships with the NAF-N need to be further constrained. For this purpose, a dense dataset of 2D geophysical images (high-resolution seismic reflection data, sparker reflection, CHIRP sub-bottom profiling), as well as multibeam bathymetry, have been acquired in 2008, 2010, 2013 and 2014 during TAMAM and SOMAR cruises, primarily in the southern shelf of the Sea of Marmara. The 15-20 km-wide southern shelf ledge is relatively flat and mostly shallower than 90 m. In this shallow marine region, we have been able to image the detailed stratigraphic record associated with the 125 ka and younger glacio-eustatic cycles and, notably, to identify paleo-shorelines at water depths shallower than 100 m. Several erosional unconformities, laterally correlative to low-stand deltas have been regionally linked to the stratigraphic boundaries previously defined for the last 130-540 ka. While the present-day shelf is relatively flat, a shallow ridge separates the inner and outer parts

  1. The 3-D Tectonic Crustal Stress Field and Style of Faulting Along the Pacific North America Plate Boundary in Southern California

    NASA Astrophysics Data System (ADS)

    Yang, W.; Hauksson, E.

    2012-12-01

    We invert for the state of stress in the southern California crust using recent high quality earthquake focal mechanisms catalog (1981-2010). To interpret the stress field we determine the maximum horizontal compressive stress (SHmax) orientations and the style of faulting across southern California at four different scales of resolution, with grid spacing of 5 and 10 km, and with 15 or 30 events per grid. The stress field is best resolved where seismicity rates are high but sufficient data are available to constrain the stress field across most of the region. The trend of SHmax exhibits significant regional and local spatial heterogeneities. The regional trend of SHmax varies from north along the San Andreas system to NNE to the east in the Eastern California Shear Zone as well as to the west, within the Continental Borderland and the western Transverse Ranges. The transition zones from one state of stress to the other are very sharp and occur over a distance of a few kilometers, following a trend from Yucca Valley to Imperial Valley to the east, and the western edge of the Peninsular Ranges to the west. The local scale heterogeneities in the SHmax trend include NNW trends along the San Andreas Fault near Cajon Pass, Tejon Pass, and the Cucapa Range, as well as NNE trends near the northern San Jacinto Fault and the Wheeler Ridge region. The style of faulting exhibits similar complexity, ranging from predominantly normal faulting in the high Sierra Nevada, to strike-slip faulting along the San Andreas system, to three consecutive bands of thrust faulting in the Wheeler Ridge area and the western Transfer Ranges. The local variations in the style of faulting include normal faulting at the north end of the San Jacinto Fault and scattered regions of thrust faulting. We compare the pattern of SHmax trend in the crust with the GPS measured maximum shortening strain rate tensor and upper mantle anisotropy. The regional variations in the SHmax trends are very similar to

  2. Petrologic, geochemical, and geochronologic constraints on the tectonic evolution of the southern Appalachian orogen, Blue Ridge Province of western North Carolina

    NASA Astrophysics Data System (ADS)

    Anderson, Eric Douglas

    2011-07-01

    The Blue Ridge Province of western North Carolina contains a wide variety of metamorphosed igneous and sedimentary rocks that record the tectonic effects of Precambrian and Paleozoic orogenic cycles. Tectonic interpretations of the events that led to the present configuration are varied and often conflicting. This investigation examines metamorphosed mafic rocks that are widely interpreted to have formed during the closure of ocean basins. Metabasites, and specifically eclogites, have a tendency to mark tectonic sutures and frequently preserve pressure (P), temperature (T), and age data (t) that can be gleaned from mineral equilibria and U-Pb isotopic compositions. As such, the examination of the metabasites is considered the key to understanding the orogenic history of the southern Blue Ridge where these metabasites occur. Chapter 2 is an investigation of the retrograde reactions related to the decompression of sodic pyroxenes that react to form diopside-plagioclase-hornblende-quartz symplectites as stability fields are overstepped during isothermal decompression. In Chapter 3 metabasites from the central and eastern Blue Ridge are re-examined and P-T pathways of these lithologies are determined. The argument is made that the Taconic orogeny of the Blue Ridge is the result of a continent-continent collision event that culminated in a mega-melange that coincides with the Cullowhee terrane and the eastern Blue Ridge melange of western North Carolina. Chapter 4 contains the results of a geochronological investigation of the Precambrian basement complex of the eastern Great Smoky Mountains. Chapter 5 is a whole rock geochemical study of the same basement complex. In Chapter 6, a potential lithologic correlation between the southern Blue Ridge basement and the Arequipa-Antofalla block of Peru is discussed. The geologic history of western South America from the Mesoproterozoic through Cambrian is summarized, a potential isotope-based lithologic correlation is proposed

  3. Respiratory Microbiome of Endangered Southern Resident Killer Whales and Microbiota of Surrounding Sea Surface Microlayer in the Eastern North Pacific.

    PubMed

    Raverty, Stephen A; Rhodes, Linda D; Zabek, Erin; Eshghi, Azad; Cameron, Caroline E; Hanson, M Bradley; Schroeder, J Pete

    2017-03-24

    In the Salish Sea, the endangered Southern Resident Killer Whale (SRKW) is a high trophic indicator of ecosystem health. Three major threats have been identified for this population: reduced prey availability, anthropogenic contaminants, and marine vessel disturbances. These perturbations can culminate in significant morbidity and mortality, usually associated with secondary infections that have a predilection to the respiratory system. To characterize the composition of the respiratory microbiota and identify recognized pathogens of SRKW, exhaled breath samples were collected between 2006-2009 and analyzed for bacteria, fungi and viruses using (1) culture-dependent, targeted PCR-based methodologies and (2) taxonomically broad, non-culture dependent PCR-based methodologies. Results were compared with sea surface microlayer (SML) samples to characterize the respective microbial constituents. An array of bacteria and fungi in breath and SML samples were identified, as well as microorganisms that exhibited resistance to multiple antimicrobial agents. The SML microbes and respiratory microbiota carry a pathogenic risk which we propose as an additional, fourth putative stressor (pathogens), which may adversely impact the endangered SRKW population.

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

    USGS Publications Warehouse

    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

    The most complete sections of Ordovician shelf rocks in Sonora are 50 km (31 mi) northwast of Hermosillo. In these sections, the Lower Ordovician is characterized by intraclastic limestone, siltstone, shale, and chert. The Middle Ordovician is mostly silty limestone and quartzite, and the Upper Ordovician is cherty limestone and some argillaceous limestone. A major disconformity separates the Middle Ordovician quartzite from the overlying Upper Ordovician carbonate rocks and is similar to the disconformity between the Middle and Upper Ordovician Eureka Quartzite and Upper Ordovician Ely Springs Dolomite in Nevada and California. In parts of northwestern Sonora, Ordovician rocks are disconformably overlain by Upper Silurain rocks. Northeastward in Sonora and Arizona, toward the craton, Ordovician rocks are progressively truncated by a major onlap unconformity and are overliand by Devonian rocks. Except in local area, Ordovician rocks are generally absent in cratonic platform sequences in northern Sonora and southern Arizona.

  5. Communication beyond the Classroom: Dimension 2010. A Thematic Index of "Dimension," 1980-2009. Selected Proceedings of the 2010 Joint Conference of the Southern Conference on Language Teaching, the Foreign Language Association of North Carolina, the North Carolina Chapter of AATSP, and the National Network of Early Language Learning

    ERIC Educational Resources Information Center

    Cherry, C. Maurice, Comp.; Wilkerson, Carol, Comp.

    2010-01-01

    "Dimension" is the annual volume containing the selected, refereed, edited Proceedings of each year's conference. The Southern Conference on Language Teaching (SCOLT), held its annual conference April 15-17, 2010, at the Winston-Salem Marriott in Winston-Salem, North Carolina, in collaboration with the Foreign Language Association of…

  6. Communication beyond the Classroom: Dimension 2010. A Thematic Index of "Dimension," 1980-2009. Selected Proceedings of the 2010 Joint Conference of the Southern Conference on Language Teaching, the Foreign Language Association of North Carolina, the North Carolina Chapter of AATSP, and the National Network of Early Language Learning

    ERIC Educational Resources Information Center

    Cherry, C. Maurice, Comp.; Wilkerson, Carol, Comp.

    2010-01-01

    "Dimension" is the annual volume containing the selected, refereed, edited Proceedings of each year's conference. The Southern Conference on Language Teaching (SCOLT), held its annual conference April 15-17, 2010, at the Winston-Salem Marriott in Winston-Salem, North Carolina, in collaboration with the Foreign Language Association of…

  7. Long-term changes in species composition of demersal fish and epibenthic species in the Jade area (German Wadden Sea/Southern North Sea) since 1972

    NASA Astrophysics Data System (ADS)

    Meyer, Julia; Kröncke, Ingrid; Bartholomä, Alexander; Dippner, Joachim W.; Schückel, Ulrike

    2016-11-01

    Within this long-term study, the short- and long-term variability of demersal fish and epibenthic species in relation to temperature and climate-driven environmental changes in the inshore tidal bay system of the Jade area was investigated. Semiquantitative sampling took place once per spring and summer period from 1972 to 2014 by using a 2 m beam trawl at one station in the Jade area (German Wadden Sea/southern North Sea). Min/max autocorrelation analysis (MAFA) and Mann-Kendall analysis revealed significant increasing trends in total abundance and species number. Homogeneity analysis revealed shifts for abundance in spring and summer in the late 1980s and for species number in the late 1980s in spring and early 2000s in summer. Abundances of the estuarine crustacean species Carcinus maenas and Liocarcinus holsatus and of the estuarine fish species Pomatoschistus spp. showed significant increasing abundances since the late 1980s. The marine juvenile species Pleuronectes platessa and Limanda limanda showed significant decreasing abundances, while abundances of Solea solea showed significant increasing abundances since the early 2000s. Abundances of L.holsatus and C. maenas showed mass occurrences since the early 2000s. Spearman correlation analysis revealed significant correlations of temperature and abundance data of some characteristic species. Statistical downscaling analysis revealed significant correlations between observations and climate indicators such as the North Sea Environmental (NSE) Index for spring. Thus, it appears that climate effects influenced the long-term variability of species number and abundance of epibenthic and demersal fish species in the Jade area, resulting in community shifts in the late 1980s and early 2000s.

  8. Metamorphic P-T-t path retrieved from metapelites in the southeastern Taihua metamorphic complex, and the Paleoproterozoic tectonic evolution of the southern North China Craton

    NASA Astrophysics Data System (ADS)

    Lu, Jun-Sheng; Zhai, Ming-Guo; Lu, Lin-Sheng; Wang, Hao Y. C.; Chen, Hong-Xu; Peng, Tao; Wu, Chun-Ming; Zhao, Tai-Ping

    2017-02-01

    The Taihua metamorphic complex in the southern part of the North China Craton is composed of tonalite-trondhjemite-granodiorite (TTG) gneisses, amphibolites, metapelitic gneisses, marbles, quartzites, and banded iron formations (BIFs). The protoliths of the complex have ages ranging from ∼2.1 to ∼2.9 Ga and was metamorphosed under the upper amphibolite to granulite facies conditions with NWW-SEE-striking gneissosity. Metapelitites from the Wugang area have three stages of metamorphic mineral assemblages. The prograde metamorphic mineral assemblage (M1) includes biotite + plagioclase + quartz + ilmenite preserved as inclusions in garnet porphyroblasts. The peak mineral assemblage (M2) consists of garnet porphyroblasts and matrix minerals of sillimanite + biotite + plagioclase + quartz + K-feldspar + ilmenite + rutile + pyrite. The retrograde mineral assemblage (M3), biotite + plagioclase + quartz, occurs as symplectic assemblages surrounding embayed garnet porphyroblasts. Garnet porphyroblasts are chemically zoned. Pseudosection calculated in the NCKFMASHTO model system suggests that mantles of garnet porphyroblasts define high-pressure granulites facies P-T conditions of 12.2 kbar and 830 °C, whereas garnet rims record P-T conditions of 10.2 kbar and 840 °C. Integrating the prograde mineral assemblages, zoning of garnet porphyroblasts with symplectic assemblages, a clockwise metamorphic P-T path can be retrieved. High resolution SIMS U-Pb dating and LA-ICP-MS trace element measurements of the metamorphic zircons demonstrate that metapelites in Wugang possibly record the peak or near peak metamorphic ages of ∼1.92 Ga. Furthermore, 40Ar/39Ar dating of biotite in metapelites suggests that the cooling of the Taihua complex may have lasted until ∼1.83 Ga. Therefore, a long-lived Palaeoproterozoic metamorphic event may define a slow exhumation process. Field relationship and new metamorphic data for the Taihua metamorphic complex does not support the previous

  9. The southern margin of the East European Craton: new results from seismic sounding and potential fields between the North Sea and Poland

    NASA Astrophysics Data System (ADS)

    Bayer, U.; Grad, M.; Pharaoh, T. C.; Thybo, H.; Guterch, A.; Banka, D.; Lamarche, J.; Lassen, A.; Lewerenz, B.; Scheck, M.; Marotta, A.-M.

    2002-12-01

    The extension of eastern Avalonia from Britain through the NE German Basin into Poland is, in some sense, a virtual structure. It is covered almost everywhere by late Paleozoic and younger sediments. Evidence for this terrane is only gathered from geophysical data and age information derived from magmatic rocks. During the last two decades, much geophysical and geological information has been gathered since the European Geotraverse (EGT), which was followed by the BABEL, LT-7, MONA LISA, DEKORP-Basin'96, and POLONAISE'97 deep seismic experiments. Based on seismic lines, a remarkable feature has been observed between the North Sea and Poland: north of the Elbe Line (EL), the lower crust is characterised by high velocities (6.8-7.0 km/s), a feature which seems to be characteristic for at least a major part of eastern Avalonia (far eastern Avalonia). In addition, the seismic lines indicate that a wedge of the East European Craton (EEC) (or Baltica) continues to the south below the southern Permian Basin (SPB)—a structure which resembles a passive continental margin. The observed pattern may either indicate an extension of the Baltic crust much farther south than earlier expected or oceanic crust of the Tornquist Sea trapped during the Caledonian collision. In either case, the data require a reinterpretation of the docking mechanism of eastern Avalonia, and the Elbe-Odra Line (EOL), as well as the Elbe Fault system, together with the Intra-Sudedic Faults, appear to be related to major changes in the deeper crustal structures separating the East European crust from the Paleozoic agglomeration of Middle European terranes.

  10. Plio-Pleistocene North-South and East-West Extension at the Southern Margin of the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    McDermott, Jeni Amber

    The tectonic significance of the physiographic transition from the low-relief Tibetan plateau to the high peaks, rugged topography and deep gorges of the Himalaya is the source of much controversy. Some workers have suggested the transition may be structurally controlled (e.g. Hodges et al., 2001), and indeed, the sharp change in geomorphic character across the transition strongly suggests differential uplift between the Himalayan realm and the southernmost Tibetan Plateau. Most Himalayan researchers credit the South Tibetan fault system (STFS), a family of predominantly east-west trending, low-angle normal faults with a known trace of over 2,000 km along the Himalayan crest (e.g. Burchfiel et al., 1992), with defining the southern margin of the Tibetan Plateau in the Early Miocene. Inasmuch as most mapped strands of the STFS have not been active since the Middle Miocene (e.g., Searle & Godin, 2003), modern-day control of the physiographic transition by this fault system seems unlikely. However, several workers have documented Quaternary slip on east-west striking, N-directed extensional faults, of a similar structural nature but typically at a different tectonostratigraphic level than the principal STFS strand, in several locations across the range (Nakata, 1989; Wu et al., 1998; Hurtado et al., 2001). In order to explore the nature of the physiographic transition and determine its relationship to potential Quaternary faulting, I examined three field sites: the Kali Gandaki valley in central Nepal (˜28°39'54"N; 83°35'06"E), the Nyalam region of south-central Tibet (28°03'23.3"N, 86°03'54.08"E), and the Ama Drime Range in southernmost Tibet (87º15'-87º50'E; 27º45'-28º30'N). Research in each of these areas yielded evidence of young faulting on structures with normal-sense displacement in various forms: the structural truncation of lithostratigraphic units, distinctive fault scarps, or abrupt changes in bedrock cooling age patterns. These structures are

  11. Hydrogeology of aquifers in Cretaceous and younger rocks in the vicinity of Onslow and southern Jones counties, North Carolina

    USGS Publications Warehouse

    Lyke, W.L.; Winner, M.D.

    1990-01-01

    Unconsolidated sediments in Onslow and Jones Counties, North Carolina overlie crystalline basement rocks and range in thickness from about 700 ft to more than 1,800 ft, thickening toward the east. This material is composed of permeable sand and limestone interlayered with relatively impermeable clay and silt beds. Sediments are divided into two groups: aquifers in Quaternary-, and Tertiary-aged rocks and aquifers in Cretaceous-aged rocks. Aquifers in the Cretaceous rocks provide most of the groundwater for public supplies and are the focus of this report. The aquifers in Cretaceous rocks are the Peedee, Black Creek, upper Cape Fear, and lower Cape Fear aquifers, which are composed of beds or groups of beds of sand and gravel. Each aquifer is overlain by a clay and silt bed, that impedes the flow of water between aquifers. The thickness of Cretaceous hydrogeologic units ranges from about 700 ft to more than 1, 300 ft. Hydrogeologic units are correlated using 60 geophysical logs and accompanying drillers ' logs along with water level and water quality data. Three hydrogeologic sections demonstrate the continuity of the aquifers and confining units, show water levels and chloride concentration in water from test intervals, and delineate where chloride concentration in water exceeds 250 mg/L within each aquifer. Maps of each aquifer in Cretaceous rocks show altitude of its top, thickness, sand percentage, and the transition from freshwater to saltwater. Maps of the confining units show thickness and sand percentage of each.

  12. Quaternary magnetic and oxygen isotope stratigraphy in diatom-rich sediments of the southern Gardar Drift (IODP Site U1304, North Atlantic)

    NASA Astrophysics Data System (ADS)

    Xuan, Chuang; Channell, James E. T.; Hodell, David A.

    2016-06-01

    The sediment sequence from Integrated Ocean Drilling Program (IODP) Site U1304 (53°03.40‧N, 33°31.78‧W; water depth, 3024 m) on the southern Gardar Drift, North Atlantic Ocean, covers the last ∼1.8 Myr with a mean sedimentation rate of ∼15 cm/kyr. At Site U1304, paleomagnetic directional and relative paleointensity (RPI) records have been generated for the last ∼1.5 Myr, and benthic oxygen isotope data for the last ∼1 Myr. The age model for Site U1304 was established by matching δ18O and RPI data to calibrated reference records. Prominent intervals of diatom mats at Site U1304 are associated with the latter stages of interglacial marine isotope stages (MIS) 9, 11, 13, 15, 21, 27 and 35, and with the weak glacial of MIS 14. The deposition of diatom mats, and associated diluted magnetic mineral concentrations, leads to weak magnetizations and susceptibilities in these intervals. Comparison of histograms of paleomagnetic directions and RPI from diatom-rich sediments and from surrounding silty clays indicates that, although results from diatom-rich sediments are more scattered, the occurrence of diatom mats does not appreciably distort the paleomagnetic directional and RPI records. Site U1304 sediments record the Matuyama/Brunhes boundary (∼772 ka), the Jaramillo Subchron (∼993-1071 ka) and the Cobb Mountain Subchron (∼1193-1219 ka), as well as three apparent geomagnetic excursions in the Matuyama Chron, interpreted as the "Kamikatsura/Santa Rosa", "Punaruu", and "Gardar" excursions, at ∼888 ka, ∼1124 ka, and ∼1463 ka, respectively. The Site U1304 RPI record can be correlated with the PISO-1500 RPI stack and with other high-resolution RPI records from the North Atlantic Ocean. Wavelet analyses performed on the Site U1304 RPI record and a new high-resolution North Atlantic paleointensity stack for the last 1500 kyr (HINAPIS-1500), comprising Ocean Drilling Program (ODP) Sites 983, 984 and IODP Sites U1306 and U1304, did not reveal significant

  13. Effects of climate warming, North Atlantic Oscillation, and El Niño-Southern Oscillation on thermal conditions and plankton dynamics in northern hemispheric lakes.

    PubMed

    Gerten, Dieter; Adrian, Rita

    2002-03-08

    Impacts of climate warming on freshwater ecosystems have been documented recently for a variety of sites around the globe. Here we provide a review of studies that report long-term (multidecadal) effects of warming trends on thermal properties and plankton dynamics in northern hemispheric lakes. We show that higher lake temperatures, shorter periods with ice cover, and shorter stagnation periods were common trends for lakes across the hemisphere in response to the warmer conditions. Only for shallow dimictic lakes was it observed that deep-water temperatures decreased. Moreover, it became evident that phytoplankton dynamics and primary productivity altered in conjunction with changes in lake physics. Algal spring blooms developed early and were more pronounced in several European lakes after mild winters with short ice cover periods, and primary productivity increased in North American lakes. Effects of elevated temperatures on zooplankton communities were seen in an early development of various species and groups, as is documented for cladocerans, copepods, and rotifers in European lakes. Furthermore, thermophile species reached higher abundance in warmer years. Obviously, the nature of responses is species specific, and depends on the detailed seasonal patterning of warming. Complex responses such as effects propagating across trophic levels are likely, indicating that observed climate-ecosystem relationships are not generally applicable. Nonetheless, the picture emerges that climate-driven changes in freshwater ecosystems may be synchronised to a certain extent among lakes even over great distances if climatic influences are not masked by anthropogenic impacts or differences in lake morphology. Macro-scale climatic fluctuations--such as the North Atlantic Oscillation or the El Niño-Southern Oscillation--were identified as the most important candidates responsible for such coherence, with the former predominating in Europe and the latter in North America. We

  14. Assessment and analysis of noise levels in and around Ib river coalfield, Orissa, India.

    PubMed

    Mohapatra, Haraprasad; Goswami, Shreerup

    2012-05-01

    Heavy earth moving machineries, different capacities of dumpers and loaders, blasting and drilling make the mining environment noisy. A study was carried out to assess the noise level in different opencast projects in and around Belpahar and Brajarajnagar areas of Ib river coalfield. Noise assessment was carried out in various residential, commercial and industrial places. The noise levels, especially L(eq) values of different wheel loaders, dumpers, shovel and crusher units were also assessed and were more than permissible limit (90dB) in some of their operating conditions. Sound ressure level measurements while drilling into coal and overburden at Lakhanpur opencast project yielded noise levels (L(eq)) of 81.33 to 96.2 dB. Thus, these L(eq) values of drilling machines in most of the operating conditions were above permissible limit. The average noise intensities (6 a.m.-10 p.m.: 51.6-60.875dB and 10 p.m.-6 a.m.: 42.6-49.8dB) and L(eq) values (6 a.m.-10 p.m.: 50.9-67.0dB and 10 p.m.-6 a.m.: 40.8-53.3dB) during both day and night time of the residential areas around the Ib river coalfield were in close proximity or beyond the permissible limit. The L(eq) values at some of the commercial and industrial places were beyond (6 a.m.-10 p.m.: 61.6-88.3 dB and 10 p.m.-6 a.m.: 55.4-64.8dB) permissible limit. However, in most of the cases, the L(max) noise values were more (6 a.m.-10 p.m.: 68.5-91.4 dB and 10 p.m.-6 a.m.: 69.3-76.4dB) than the permissible limit. Analysis of variance was also computed for heavy earth moving machineries in different operating conditions and also for different residential, commercial and industrial places to infer the level of significance. The difference of noise intensity produced by different wheel loaders at Lakhanpur and Lilari opencast projects, drilling machines at Lakhanpur opencast project, 50 tons capacity dumpers at various conditions of Ib river coalfield within the same operating condition was significant at both 5% and 1% levels

  15. Polychlorinated biphenyls in marine sediments from the southern North Sea and Scheldt estuary: a ten-year study of concentrations, patterns and trends.

    PubMed

    Roose, Patrick; Raemaekers, Marc; Cooreman, Kris; Brinkman, Udo A Th

    2005-07-01

    The paper reports the concentrations and patterns of CBs in sediments of the Belgian part of the southern North Sea and the Scheldt estuary for the period 1991-2001. The long-term analytical performance was well within the quality assurance boundaries set at the outset of the study and is consistent with the state of the art for this type of analysis. The CB concentrations (given as the median of the sum of IUPAC Nos 28, 52, 101, 118, 138, 153 and 180) vary between 0.1 microg kg(-1) and 50 microg kg(-1) dry weight in the total sediment and it could be demonstrated that CB patterns in the fine fraction of the sediment were closely similar throughout the investigated area. Isolation of the fine fraction (<63 microm) by sieving can be regarded as a physical normalisation to reduce the differences in sediment granulometric composition. It allows for a better understanding of CB distribution and patterns and improves the trend analysis. A significant downward trend could not be found at any of the stations, which suggests that CB levels have not been changing in the area of interest in the past decade.

  16. Depositional environment and origin of the Lilaozhuang Neoarchean BIF-hosted iron-magnesite deposit on the southern margin of the North China Craton

    NASA Astrophysics Data System (ADS)

    Huang, Hua; Zhang, LianChang; Fabre, Sébastien; Wang, ChangLe; Zhai, MingGuo

    2016-08-01

    The Neoarchean Lilaozhuang iron-magnesite deposit is located in the middle of the Huoqiu banded iron formation (BIF) ore belt in Anhui Province on the southern margin of the North China Craton. The Huoqiu BIF is the unique one that simultaneously develops quartz-type, silicate-type, and carbonate-type magnetite in the region. The Lilaozhuang deposit is characterized by magnesium-rich carbonate (magnesite) in magnetite ores. The BIF-hosted iron ores include mainly of silicate type and carbonate type, with a small amount of quartz type, which chiefly exhibit banded and massive structure, with minor disseminated structure. The magnesite ores occur as crystal-like bright white and exhibits massive structure. The Y/Ho ratio and REY pattern of both iron and magnesite ores are similar to that of seawater, while Eu shows positive anomaly, which is the sign of seafloor hydrothermal mixture. These features suggest that ore-forming materials of iron and magnesium in the Lilaozhuang deposit are mainly from the mixture of seafloor hydrothermal and seawater. Both ores do not exhibit negative Ce anomaly, which indicates that the deposit was formed in an environment showing a lack of oxygen. C-O isotopic compositions indicate that magnesite ore has been reformed by metamorphism of low amphibolite facies and later hydrothermal alteration. Based on the comprehensive analysis, authors suggest that iron and magnesite ores in the Lilaozhuang deposits formed in a confined sea basin on continental margin and was influenced by later complex geological processes.

  17. Spatial variability in structural and functional aspects of macrofauna communities and their environmental parameters in the Jade Bay (Wadden Sea Lower Saxony, southern North Sea)

    NASA Astrophysics Data System (ADS)

    Schückel, Ulrike; Beck, Melanie; Kröncke, Ingrid

    2013-03-01

    Spatial distribution and functional structure of intertidal benthic macrofauna in relation to environmental variables in the Jade Bay (southern North Sea) were studied and compared with other intertidal areas of the Wadden Sea. A total of 128 stations covering the whole Jade Bay were sampled in summer 2009. A total of 114 taxa were found. Highest species numbers occurred in the subtidal areas, whereas highest mean abundances were found in the upper intertidal areas. Based on species abundance data, six significantly distinct macrofauna communities in the Jade Bay were identified and evaluated with multivariate statistics, univariate correlations and canonical correspondence analysis. Differences in these community patterns were caused by the response of the dominant species ( Hydrobia ulvae, Tubificoides benedii, Pygospio elegans, Caulleriella killariensis, Scoloplos armiger, Urothoe poseidonis, Microprotopus maculatus) to prevailing environmental conditions along the gradient from the lower and exposed sandy intertidal areas via intermediate mixed sediments to the upper mudflat areas. Distribution patterns in relation to tidal zonation were best explained by variability in submergence time, Chlorophyll a (chl a) content and sediment composition (mud content), which are proxies for hydrodynamic conditions and food availability. Species inventory and species richness were comparable with other intertidal areas of the Wadden Sea, but the Jade Bay differs from these areas regarding dominant species. Differences in sediment composition and morphological characteristics (macrotidal versus mesotidal Wadden Sea areas) are discussed for comparison of regional differences.

  18. Kinematics of the Chugach metamorphic complex, southern Alaska: Plate geometry in the north Pacific margin during the Late Cretaceous to Eocene

    NASA Astrophysics Data System (ADS)

    Scharman, Mitchell R.; Pavlis, Terry L.

    2012-08-01

    The Paleogene plate geometry of the north Pacific margin is poorly constrained because all of the plates involved, except the trailing Pacific plate, have been subducted. However, the kinematic history of the Chugach metamorphic complex in southern Alaska constrains plate configurations because of its link to ridge-subduction. We synthesize recent regional mapping of the complex, finite strain data, and geochronology to show that progressive deformation records the Paleogene triple junction interaction occurred over a period of less than 2 m.y. across ˜350 km of the margin. We document that 140-190 km of distributed dextral shear occurred across the complex during the latest phase of deformation in the complex. This analysis suggests dextral motion of at least 70-95 mm/yr which can account for most, or all, of the margin parallel plate motion during a brief period of the Eocene. We use these results to compare and evaluate possible plate configurations based on older and newer plate motion models. Using modern plate motion models it is difficult to reconcile a Kula-Farallon ridge-subduction model with the available data, but our preferred plate geometry model involving a Kula-Resurrection ridge provides a reasonable explanation for our observations.

  19. A novel adaptive biogeochemical model, and its 3-D application for a decadal hindcast simulation of the biogeochemistry of the southern North Sea

    NASA Astrophysics Data System (ADS)

    Kerimoglu, Onur; Hofmeister, Richard; Wirtz, Kai

    2016-04-01

    Adaptation and acclimation processes are often ignored in ecosystem-scale model implementations, despite the long-standing recognition of their importance. Here we present a novel adaptive phytoplankton growth model where acclimation of the community to the changes in external resource ratios is accounted for, using optimality principles and dynamic physiological traits. We show that the model can reproduce the internal stoichiometries obtained at marginal supply ratios in chemostat experiments. The model is applied in a decadal hindcast simulation of the southern North Sea, where it is coupled to a 2-D benthic model and a 3-D hydrodynamic model in an approximately 1.5km horizontal resolution at the German Bight coast. The model is shown to have good skill in capturing the steep, coastal gradients in the German Bight, suggested by the match between the estimated and observed dissolved nutrient and chlorophyll concentrations. We then analyze the differential sensitivity of the coastal and off-shore zones to major drivers of the system, such as riverine nutrient loads. We demonstrate that the relevance of phytoplankton acclimation varies across coastal gradients and can become particularly significant in terms of summer nutrient depletion.

  20. Impact of a phytoplankton bloom on the diversity of the active bacterial community in the southern North Sea as revealed by metatranscriptomic approaches.

    PubMed

    Wemheuer, Bernd; Güllert, Simon; Billerbeck, Sara; Giebel, Helge-Ansgar; Voget, Sonja; Simon, Meinhard; Daniel, Rolf

    2014-02-01

    Despite their importance for ecosystem functioning, little is known about the composition of active marine bacterioplankton communities. Hence, this study was focused on assessing the diversity of these communities in the southern North Sea and examining the impact of a phytoplankton spring bloom on the ambient bacterioplankton community. Community composition in and outside the bloom was assessed in 14 samples by pyrosequencing-based analysis of 16S rRNA gene amplicons generated from environmental RNA. The data set comprised of 211 769 16S rRNA gene sequences. Proteobacteria were the predominant phylogenetic group with Alphaproteobacteria and Gammaproteobacteria as the most abundant classes. Actinobacteria and Bacteroidetes were identified in minor abundances. Active bacterial communities were dominated by few lineages such as the Roseobacter RCA cluster and the SAR92 clade. Community structures of three selected samples were also assessed by direct sequencing of cDNA generated from rRNA-depleted environmental RNA. Generated data sets comprised of 988 202 sequences. Taxonomic assignment of the reads confirmed the predominance of Proteobacteria. The examined phytoplankton spring bloom affected the bacterioplankton community structures significantly. Bacterial richness was reduced in the bloom area, and the abundance of certain bacterial groups was affected by bloom presence. The SAR92 clade and the Roseobacter RCA cluster were significantly more abundant and active in the bloom. Functions affected by the bloom include photosynthesis, protein metabolism, and DNA metabolism.

  1. A 3-D shear velocity model of the southern North America and the Caribbean plates from ambient noise and earthquake tomography

    NASA Astrophysics Data System (ADS)

    Gaite, B.; Villaseñor, A.; Iglesias, A.; Herraiz, M.; Jiménez-Munt, I.

    2014-10-01

    We use group velocities from earthquake tomography together with group and phase velocities from ambient noise tomography (ANT) of Rayleigh-waves to invert for the 3-D shear-wave velocity structure (5-70 km) of the Caribbean (CAR) and southern North American (NAM) plates. The lithospheric model proposed offers a complete image of the crust and uppermost-mantle with imprints of the tectonic evolution. One of the most striking features inferred is the main role of the Ouachita-Marathon-Sonora orogeny front on the crustal seismic structure of NAM plate. A new imaged feature is the low crustal velocities along USA-Mexico border. The model also shows a break of the E-W mantle velocity dichotomy of the NAM and CAR plates beneath the Isthmus of Tehuantepec and Yucatan Block. High upper-mantle velocities along the Mesoamerican Subduction Zone coincide with inactive volcanic areas while the lowest velocities correspond to active volcanic arcs and thin lithospheric mantle regions.

  2. Depositional environment and origin of the Lilaozhuang Neoarchean BIF-hosted iron-magnesite deposit on the southern margin of the North China Craton

    NASA Astrophysics Data System (ADS)

    Huang, Hua; Zhang, LianChang; Fabre, Sébastien; Wang, ChangLe; Zhai, MingGuo

    2017-07-01

    The Neoarchean Lilaozhuang iron-magnesite deposit is located in the middle of the Huoqiu banded iron formation (BIF) ore belt in Anhui Province on the southern margin of the North China Craton. The Huoqiu BIF is the unique one that simultaneously develops quartz-type, silicate-type, and carbonate-type magnetite in the region. The Lilaozhuang deposit is characterized by magnesium-rich carbonate (magnesite) in magnetite ores. The BIF-hosted iron ores include mainly of silicate type and carbonate type, with a small amount of quartz type, which chiefly exhibit banded and massive structure, with minor disseminated structure. The magnesite ores occur as crystal-like bright white and exhibits massive structure. The Y/Ho ratio and REY pattern of both iron and magnesite ores are similar to that of seawater, while Eu shows positive anomaly, which is the sign of seafloor hydrothermal mixture. These features suggest that ore-forming materials of iron and magnesium in the Lilaozhuang deposit are mainly from the mixture of seafloor hydrothermal and seawater. Both ores do not exhibit negative Ce anomaly, which indicates that the deposit was formed in an environment showing a lack of oxygen. C-O isotopic compositions indicate that magnesite ore has been reformed by metamorphism of low amphibolite facies and later hydrothermal alteration. Based on the comprehensive analysis, authors suggest that iron and magnesite ores in the Lilaozhuang deposits formed in a confined sea basin on continental margin and was influenced by later complex geological processes.

  3. Decay of deep water convection in CMIP5 GCMs in the North Atlantic and Southern Ocean in the 21st century

    NASA Astrophysics Data System (ADS)

    Molodtsov, S.; Anis, A.; Marinov, I.; Cabre, A.

    2016-12-01

    Contemporary changes in the climate system due to anthropogenic activity have already resulted in unprecedented melting rates of the polar ice caps. This in turn may have a significant impact on the thermohaline circulation in the future. The freshening of the surface waters increases stable stratification in regions of deep water formation, eventually triggering a weakening and, ultimately, may bring to a cessation of deep convection in these regions. Here we present comparatively an analysis of the response of deep convective processes in the North Atlantic (NA) and Southern Ocean (SO) to anthropogenic forcing using output from the latest generation of Earth System Models (ESM), part of the CMIP5 intercomparison. Our findings indicate an attenuation of deep convection by the end of the 21st century from ESM simulations under representative concentration pathways (RCP) 8.5 scenario when compared to the years under historical scenario in both NA and SO. The average depth of the mixed layer in the regions studied during March/September, the months with maximum mixed layer depths in the NA/SO, respectively, was found to decrease dramatically by the end of the 21st century. Furthermore, the increase in stratification and decrease in mixed layer depths, resulting in the decay of deep convection, leads to accumulation of excess heat, previously released during the convection events, in the ocean interior in both regions.

  4. Temporal variations in 13C and 14C concentrations in particulate organic matter from the southern North Sea

    NASA Astrophysics Data System (ADS)

    Megens, L.; van der Plicht, J.; de Leeuw, J. W.

    2001-09-01

    As a new approach for the characterization and determination of the origin of particulate organic matter (POM) in coastal waters, we measured the 14C activity and 13C/12C isotope ratios and applied molecular analysis by means of AMS, IRMS and pyrolysis-GCMS for both bulk samples and isolated fractions of POM from the North Sea off the Dutch coast. The fractions were obtained by a sequence of chemical treatments separating polysaccharides, proteins, lipids and non-hydrolysable resistant compounds. The 13C/12C and 14C/12C isotope ratios, the 14C activities and the polysaccharide/protein contents were high in the spring and summer samples and significantly lower in the autumn and winter samples. This is explained by the high amount of marine phytoplankton in summer and spring, and the presence of detrital material in autumn and winter. It was noted that phytoplankton as found in the spring and summer samples was ca. 20% enriched in 14C with respect to natural values, very likely caused by 14C contamination of the water from the English Channel by the nuclear fuel reprocessing plant at La Hague, Normandy, France. The 13C/12C isotope ratios and 14C activity data show that the winter sample was not a simple mixture of relatively recent marine phytoplankton and POM from the rivers Rhine and Meuse. The main source of both terrestrial and marine organic matter in POM in winter is resuspended organic matter derived from eroded sea floor deposits with relatively low contributions of polysaccharides and proteins.

  5. Hydrologic reconnaissance of the Wasatch Plateau-Book Cliffs coal-fields area, Utah

    USGS Publications Warehouse

    Waddell, Kidd M.; Contratto, P. Kay; Sumsion, C.T.; Butler, John R.

    1981-01-01

    Data obtained during a hydrologic reconnaissance in 1975-77 in the Wasatch Plateau-Book Cliffs coal-fields area of Utah were correlated with existing long-term data. Maps were prepared showing average precipitation, average streamflow, stream temperature, ground- and surface-water quality, sediment yield, and geology. Recommendations were made for additional study and suggested approaches for continued monitoring in the coalfields areas.moDuring the 1931-75 water years, the minimum discharges for the five major streams that head in the area ranged from about 12,000 to 26,000 acre-feet per year, and the maximum discharges ranged from about 59,000 to 315,000 acre-feet per year. Correlations indicate that 3 years of low-flow records at stream sites in the Wasatch Plateau would allow the development of relationships with long-term sites that can be used to estimate future low-flow records within a standard error of about 20 percent.Most water-quality degradation in streams occurs along the flanks of the Wasatch Plateau and Book Cliffs. In the uplands, dissolved-solids concentrations generally ranged from less than 100 to about 250 milligrams per liter, and in the lowlands, the concentrations ranged from about 250 to more than 6,000 milligrams per liter.Most springs in the Wasatch Plateau and Book Cliffs discharge from the Star Point Sandstone or younger formations, and the water generally contains less than about 1,000 milligrams per liter of dissolved solids. The discharges of 65 springs ranged from about 0.2 to 200 gallons per minute. The Blackhawk Formation, which is the principal coal-bearing formation, produces water in many of the mines. The dissolved-solids concentration in water discharging from springs and mines in the Blackhawk ranged from about 60 to 800 milligrams per liter.In the lowland areas, the Ferron Sandstone Member of the Maneos Shale appears to have the most potential for subsurface development of water of suitable chemical quality for human

  6. Depositional setting, petrology and chemistry of Permian coals from the Paraná Basin: 2. South Santa Catarina Coalfield, Brazil

    USGS Publications Warehouse

    Kalkreuth, W.; Holz, M.; Mexias, A.; Balbinot, M.; Levandowski, J.; Willett, J.; Finkelman, R.; Burger, H.

    2010-01-01

    In Brazil economically important coal deposits occur in the southern part of the Paran?? Basin, where coal seams occur in the Permian Rio Bonito Formation, with major coal development in the states of Rio Grande de Sul and Santa Catarina. The current paper presents results on sequence stratigraphic interpretation of the coal-bearing strata, and petrological and geochemical coal seam characterization from the South Santa Catarina Coalfield, Paran?? Basin.In terms of sequence stratigraphic interpretation the precursor mires of the Santa Catarina coal seams formed in an estuarine-barrier shoreface depositional environment, with major peat accumulation in a high stand systems tract (Pre-Bonito and Bonito seams), a lowstand systems tract (Ponta Alta seam, seam A, seam B) and a transgressive systems tract (Irapu??, Barro Branco and Treviso seams).Seam thicknesses range from 1.70 to 2.39. m, but high proportions of impure coal (coaly shale and shaley coal), carbonaceous shale and partings reduce the net coal thickness significantly. Coal lithoypes are variable, with banded coal predominant in the Barro Branco seam, and banded dull and dull coal predominantly in Bonito and Irapu?? seams, respectively. Results from petrographic analyses indicate a vitrinite reflectance range from 0.76 to 1.63 %Rrandom (HVB A to LVB coal). Maceral group distribution varies significantly, with the Barro Branco seam having the highest vitrinite content (mean 67.5 vol%), whereas the Irapu?? seam has the highest inertinite content (33.8. vol%). Liptinite mean values range from 7.8. vol% (Barro Branco seam) to 22.5. vol% (Irapu?? seam).Results from proximate analyses indicate for the three seams high ash yields (50.2 - 64.2wt.%). Considering the International Classification of in-Seam Coals, all samples are in fact classified as carbonaceous rocks (>50wt.% ash). Sulfur contents range from 3.4 to 7.7 wt.%, of which the major part occurs as pyritic sulfur. Results of X-ray diffraction indicate the

  7. Coal fire mapping of East Basuria Colliery, Jharia coalfield using vertical derivative technique of magnetic data

    NASA Astrophysics Data System (ADS)

    Pal, S. K.; Vaish, Jitendra; Kumar, Sahadev; Bharti, Abhay Kumar

    2016-02-01

    The present study deals with the coal fire mapping of East Basuria Colliery, Jharia coalfield, India, using the magnetic method. It is based on the fact that rise in temperature would result significant changes in magnetic susceptibility and thermo-remanent magnetization (TRM) of the overlying rocks. Magnetism increases slowly with the rise of temperature until the Curie temperature. Generally, rock/ overburden loses magnetization and becomes paramagnetic due to heating to Curie temperature, which results with significant reduction in magnetic susceptibility. However, magnetism increases significantly after cooling below the Curie temperature. Several data processing methods such as diurnal correction, reduction to pole (RTP), first and second vertical derivatives have been used for analysis of magnetic data and their interpretation. It is observed that the total magnetic field intensity anomaly of the area varies approximately from 44850 to 47460 nT and the residual magnetic anomaly varies approximately from -1323 to 1253 nT. The range of the magnetic anomaly after RTP is approximately 1050-1450 nT. About 20 low magnetic anomaly zones have been identified associated with active coal fire regions and 11 high magnetic anomaly zones have been identified associated with non-coal fire regions using vertical derivative techniques.

  8. Raman spectral characteristics of magmatic-contact metamorphic coals from Huainan Coalfield, China

    NASA Astrophysics Data System (ADS)

    Chen, Shancheng; Wu, Dun; Liu, Guijian; Sun, Ruoyu

    2017-01-01

    Normal burial metamorphism of coal superimposed by magmatic-contact metamorphism makes the characteristics of the Raman spectrum of coal changed. Nine coal samples were chosen at a coal transect perpendicular to the intrusive dike, at the No. 3 coal seam, Zhuji Coal Mine, Huainan Coalfield, China, with different distances from dike-coal boundary (DCB). Geochemical (proximate and ultimate) analysis and mean random vitrinite reflectance (R0, %) indicate that there is a significant relationship between the values of volatile matter and R0 in metamorphosed coals. Raman spectra show that the graphite band (G band) becomes the major band but the disordered band (D band) disappears progressively, with the increase of metamorphic temperature in coals, showing that the structural organization in high-rank contact-metamorphosed coals is close to that of well-crystallized graphite. Evident relationships are observed between the calculated Raman spectral parameters and the peak metamorphic temperature, suggesting some spectral parameters have the potentials to be used as geothermometers for contact-metamorphic coals.

  9. Raman spectral characteristics of magmatic-contact metamorphic coals from Huainan Coalfield, China.

    PubMed

    Chen, Shancheng; Wu, Dun; Liu, Guijian; Sun, Ruoyu

    2017-01-15

    Normal burial metamorphism of coal superimposed by magmatic-contact metamorphism makes the characteristics of the Raman spectrum of coal changed. Nine coal samples were chosen at a coal transect perpendicular to the intrusive dike, at the No. 3 coal seam, Zhuji Coal Mine, Huainan Coalfield, China, with different distances from dike-coal boundary (DCB). Geochemical (proximate and ultimate) analysis and mean random vitrinite reflectance (R0, %) indicate that there is a significant relationship between the values of volatile matter and R0 in metamorphosed coals. Raman spectra show that the graphite band (G band) becomes the major band but the disordered band (D band) disappears progressively, with the increase of metamorphic temperature in coals, showing that the structural organization in high-rank contact-metamorphosed coals is close to that of well-crystallized graphite. Evident relationships are observed between the calculated Raman spectral parameters and the peak metamorphic temperature, suggesting some spectral parameters have the potentials to be used as geothermometers for contact-metamorphic coals.

  10. Arsenic in coal of the Thar coalfield, Pakistan, and its behavior during combustion.

    PubMed

    Ali, Jamshed; Kazi, Tasneem G; Baig, Jameel A; Afridi, Hassan I; Arain, Mariam S; Brahman, Kapil D; Naeemullah; Panhwar, Abdul H

    2015-06-01

    The aim of the current study is to evaluate the occurrence of arsenic in coal collected from Thar coalfield, Pakistan, and its behavior during the combustion. Fractionation of arsenic (As) in coal samples was carried out by Community Bureau of Reference sequential extraction scheme (BCR-SES) and single-step-based BCR method (BCR-SS). These methods are validated using the certified reference material of sediment BCR 701 and standard addition method. The stepwise fractions of As in laboratory-made ash (LMA) have been also investigated. The extractable As content associated with different phases in coal and LMA samples were analyzed by electrothermal atomic absorption spectrophotometer. The extraction efficiency of As by BCR-SS was slightly higher than BCR-SES, while the difference was not significant (p < 0.05). The BCR-SS method is a time-saving method because it can reduce the extraction time from 51 to 22 h. The As contents in LMA revealed that during combustion of the coal, >85 % of As may be released into atmosphere. The relative mobility of As in the coal samples was found in increasing order as follows: oxidizable fraction < reducible fraction < acid soluble fraction. The total and extractable As obtained by BCR-SES and BCR-SS were higher in coal samples of block III as compared to block V (p > 0.05).

  11. Evaluation of the fate of arsenic-contaminated groundwater at different aquifers of Thar coalfield Pakistan.

    PubMed

    Ali, Jamshed; Kazi, Tasneem G; Baig, Jameel A; Afridi, Hassan I; Arain, Mariam S; Ullah, Naeem; Brahman, Kapil D; Arain, Sadaf S; Panhwar, Abdul H

    2015-12-01

    In present study, the ground water at different aquifers was evaluated for physicochemical parameters, iron, total arsenic, total inorganic arsenic and arsenic species (arsenite and arsenate). The samples of groundwater were collected at different depths, first aquifer (AQ1) 50-60 m, second aquifer (AQ2) 100-120 m, and third aquifer (AQ3) 200-250 m of Thar coalfield, Pakistan. Total inorganic arsenic was determined by solid phase extraction using titanium dioxide as an adsorbent. The arsenite was determined by cloud point extraction using ammonium pyrrolidinedithiocarbamate as a chelating reagent, and resulted complex was extracted by Triton X-114. The resulted data of groundwater were reported in terms of basic statistical parameters, principal component, and cluster analysis. The resulted data indicated that physicochemical parameters of groundwater of different aquifers were exceeded the World Health Organization provisional guideline for drinking water except pH and SO4(2-). The positive correlation was observed between arsenic species and physicochemical parameters of groundwater except F(-) and K(+), which might be caused by geochemical minerals. Results of cluster analysis indicated that groundwater samples of AQ1 was highly contaminated with arsenic species as compared to AQ2 and AQ3 (p > 0.05).

  12. Modern Pearl River Delta and Permian Huainan coalfield, China: A comparative sedimentary facies study

    USGS Publications Warehouse

    Suping, P.; Flores, R.M.

    1996-01-01

    Sedimentary facies types of the Pleistocene deposits of the Modern Pearl River Delta in Guangdong Province, China and Permian Member D deposits in Huainan coalfield in Anhui Province are exemplified by depositional facies of anastomosing fluvial systems. In both study areas, sand/sandstone and mud/mudstone-dominated facies types formed in diverging and converging, coeval fluvial channels laterally juxtaposed with floodplains containing ponds, lakes, and topogenous mires. The mires accumulated thin to thick peat/coal deposits that vary in vertical and lateral distribution between the two study areas. This difference is probably due to attendant sedimentary processes that affected the floodplain environments. The ancestral floodplains of the Modern Pearl River Delta were reworked by combined fluvial and tidal and estuarine processes. In contrast, the floodplains of the Permian Member D were mainly influenced by freshwater fluvial processes. In addition, the thick, laterally extensive coal zones of the Permian Member D may have formed in topogenous mires that developed on abandoned courses of anastomosing fluvial systems. This is typified by Seam 13-1, which is a blanket-like body that thickens to as much as 8 in but also splits into thinner beds. This seam overlies deposits of diverging and converging, coeval fluvial channels of the Sandstone D, and associated overbank-floodplain deposits. The limited areal extent of lenticular Pleistocene peat deposits of the Modern Pearl River Delta is due to their primary accumulation in topogenous mires in the central floodplains that were restricted by contemporaneous anastomosing channels.

  13. Fast hydrodynamic model for medium- and long-term dispersion in seawater in the English Channel and southern North Sea, qualitative and quantitative validation by radionuclide tracers

    NASA Astrophysics Data System (ADS)

    du Bois, P. Bailly; Dumas, F.

    The database for medium- and long-term model validation using 125Sb released by the La Hague reprocessing plant includes 1400 measurements performed between 1987 and 1994 in the English Channel and the North Sea and data for each release since 1982. Antimony-125 has a conservative behaviour in water masses over a period of several years. These data can be used qualitatively and quantitatively to compare the measured concentrations with the calculated ones and quantities of tracers. Tritium measurements are also available for model calibration. A two-dimensional hydrodynamic model has been developed to allow repetitive long-term simulations. This model uses a database of residual tidal currents calculated using the Lagrangian barycentric method [Salomon, J.C., Guéguéniat, P., Orbi, A., Baron, Y., 1988. A Lagrangian model for long-term tidally induced transport and mixing. Verification by artificial radionuclide concentrations. In: Guary, J.C., Guéguéniat, P., Pentreath, R.J. (Eds.), Radionuclides: A Tool for Oceanography, Cherbourg 1-5 June, 1987. Elsevier Applied Science Publishers, London, New York, pp. 384-394]. The area covered by the model includes the English Channel, the southern North Sea and the Irish Sea with a mesh size of 1 km. The main adjustment parameters of this model are the sources of wind data used and the calculation method for evaluating wind stress at the sea surface. With these parameters, the fluxes of radionuclides and water masses in the English Channel and the North Sea were balanced for the whole period of field measurements (1987-1994). The correlation factor between individual measurements in seawater and calculation results is 0.88 with an average error of ±54%, the error attributable to the measurement process being 15% on average. The mean flux through the Dover Strait is 126,000 m 3 s -1, close from the one obtained from previous studies [Salomon, J.C., Breton, M., Guéguéniat, P. 1993. Computed residual flow through the Dover

  14. 1.4 kyrs of flash flood events in the Southern European Alps: implications for extreme precipitation patterns and forcing over the north-western Mediterranean area

    NASA Astrophysics Data System (ADS)

    Wilhelm, B.; Arnaud, F.; Sabatier, P.; Crouzet, C.; Brisset, E.; Guiter, F.; Reyss, J. L.; Chaumillon, E.; Tachikawa, K.; Bard, E.; Delannoy, J. J.

    2012-04-01

    the general moisture, the hydrology of large rivers and temperature patterns of the south-western European region, i.e. a low flood activity during the warm/dry MCA and conversely during the cold/wet Little Ice Age (LIA). At a sub-centennial scale, a high variability of the flood frequency is superimposed to the general increase during the LIA and appeared in phase with solar maximum. Moreover peaks of flood frequency seem to be correlated with negative autumnal NAO phases, in agreement with previous paleoflood reconstructions of Mediterranean Spanish rivers. Finally the comparison of flood frequency patterns from north-western Mediterranean sites suggests a 50-150 years oscillation mode, probably related to a NAO-like pattern, in two main NW Mediterranean atmospheric circulation patterns triggering extreme precipitations either over the Southern Alps or the Cevennes-Vivarais region.

  15. Refined Views of Strike-slip Fault Zones, Seismicity, and State of Stress Associated With the Pacific-North America Plate Boundary in Southern California

    NASA Astrophysics Data System (ADS)

    Hauksson, E.; Nicholson, C.; Shaw, J. H.; Plesch, A.; Shearer, P. M.; Sandwell, D. T.; Yang, W.

    2013-12-01

    The mostly strike-slip plate boundary in southern California is expressed as a system of late Quaternary faults or principal slip zones (PSZs), with numerous adjacent smaller slip surfaces. It is complex, even after large cumulative displacements, and consists of major fault systems with multi-stranded, non-planar fault geometry, including some in close proximity to each other. There are also secondary cross faults and low-angle detachments that interact with the PSZs accommodating main plate boundary motion. The loading of plate-tectonic strain causes the largest earthquakes along PSZs, moderate-sized events in their immediate vicinity, and small earthquakes across the whole region. We apply relocated earthquake and refined focal mechanism (1981-2013) catalogs, as well as other geophysical datasets to provide refined views of the 3D fault geometry of these active fault systems. To determine properties of individual fault zones, we measure the Euclidian distance from every hypocenter to the nearest PSZ. In addition, we assign crustal geophysical parameters such as heat flow value and shear or dilatation strain rates to each epicenter. We investigate seismogenic thickness and fault zone width as well as earthquake source processes. We find that the seismicity rate is a function of location, with the rate dying off exponentially with distance from the PSZ. About 80% of small earthquakes are located within 5 km of a PSZ. For small earthquakes, stress drops increase in size with distance away from the PSZs. The magnitude distribution near the PSZs suggests that large earthquakes are more common close to PSZs, and they are more likely to occur at greater depth than small earthquakes. In contrast, small quakes can occur at any geographical location. An optimal combination of heat flow and strain rate is required to concentrate the strain along rheologically weak fault zones, which accommodate the crustal deformation processes, causing seismicity. The regional trend of

  16. Gold distribution in As-deficient pyrite and telluride mineralogy of the Yangzhaiyu gold deposit, Xiaoqinling district, southern North China craton

    NASA Astrophysics Data System (ADS)

    Bi, Shi-Jian; Li, Jian-Wei; Zhou, Mei-Fu; Li, Zhan-Ke

    2011-12-01

    The Mesozoic Yangzhaiyu lode gold deposit is situated in the southern edge of the North China craton. Gold mineralization is hosted in Archean amphibolite facies metamorphic rocks, and consists mainly of auriferous quartz veins. Pyrite is the predominant sulfide mineral, with minor amounts of chalcopyrite, sphalerite, and galena. Based on morphology and paragenesis, there are three generations of pyrite, termed as first generation (G1), second generation (G2), and third generation (G3). They have distinct contents, occurrences, and distribution patterns of gold. The coarse-grained, euhedral G1 pyrite contains negligible to low levels of gold, whereas both invisible and visible gold are present in the fine- to medium-grained G2 pyrite that is characterized by abundance of microfractures and porosities, forming a foam-like texture. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) depth profiles indicate that invisible gold occurs either as solid solution or as nanoparticles of gold-bearing tellurides in the G2 pyrite. Visible gold is widespread and present as irregular grains and stringers of native gold mostly along grain boundaries or filling microfractures of pyrite, likely resulting from remobilization of invisible gold once locked in the G2 pyrite. The G3 pyrite, invariably intergrown with chalcopyrite, sphalerite, and galena, contains the highest levels of invisible gold. There is a positive correlation between Au, Ag, and Te, indicating that gold occurs as submicroscopic Au-bearing telluride inclusions in the host minerals. Whenever gold, either invisible or visible, is present, As is always below or only marginally higher than the detection limit of LA-ICP-MS. This indicates that As played an insignificant role in gold mineralization. Tellurides are widespread in the auriferous quartz veins, consisting mainly of petzite, calaverite, hessite, altaite, and tellurobismuthite. Native gold commonly occurs as intergrowths with tellurides

  17. The role of the sedimentary regime in shaping the distribution of subtidal sandbank environments and the associated meiofaunal nematode communities: an example from the southern North Sea.

    PubMed

    Schratzberger, Michaela; Larcombe, Piers

    2014-01-01

    We combined sediment and faunal data to explore the role of the sedimentary regime in shaping the distribution of subtidal sandbank environments and the associated meiofaunal nematode communities at Broken Bank and Swarte Bank, in the southern North Sea. A variety of sediment transport processes occur in the area, differing in the frequency and magnitude of sediment mobility, and the continuum between erosion, translation and sediment accumulation. The seabed contained a variety of bedforms, including longitudinal furrows, and small to very large sandwaves. The bed sediments were dominated by fine and medium sands, with admixtures of silt and gravel. Based on sedimentary bedforms and grain size analysis, a total of 11 sedimentary facies were delineated, of which 8 were analysed in detail for their relationships with the meiofauna. The sedimentary facies fell clearly into groups of facies, respectively representing high, high-moderate and moderate, and episodic sediment mobility. For those sedimentary facies where daily movement of sediments and bedforms occurred ('high' sediment mobility), the resulting spatially homogeneous environments were dominated by an impoverished nematode community comprising small deposit feeders and large predators. Resistance to sediment movement and the ability to exploit alternative food sources were prominent functional features of the successful colonisers. Those facies characterised by relatively infrequent sediment mobility ('episodic' and 'high-moderate and moderate' sediment mobility) comprised a heterogeneous suite of benthic habitats, containing taxonomically and functionally diverse assemblages of nematodes of various sizes, feeding types and reproductive potential. Faunal distribution patterns here indicated trade-offs between the resistance to sediment movement, environmental tolerance and competitive abilities. Our focus on diverse assemblages of organisms with high turnover times, inhabiting highly dynamic sedimentary

  18. Observations on the population dynamics of amphiura filiformis (ophiuroidea: echinodermata) in the southern north sea and its exploitation by the dab, Limanda limanda

    NASA Astrophysics Data System (ADS)

    Duineveld, G. C. A.; Van Noort, G. J.

    Density and growth of an Amphiura filiformis population living at a station in the Oyster Ground (southern North Sea) were monitored during 2 successive years (1982-1984). During this period, the density of adult animals (disk size > 4 mm) was constant and they numerically dominated the 1 mm sieve fraction of the samples. The size distribution of these adults was nearly constant and year classes were not discernable among these larger individuals. Annual recruitment was observed, but growth and survival rates of juveniles were low. During their first year, the disk size of recruits increased from 0.3 to 1.2 mm, and to 2.2 mm in their second year. Approximately 10% of the recruits of the 1982 year class survived the first 8 months. Of the recruits of the 1983 year class only 3% survived after 9 months. Consequently, the contribution by juveniles to the annual production of body tissue was small during the observation period. Adult somatic growth could not be assessed due to the apparent lack of disk growth. Regenerating arms, however, were very common among the larger individuals. Only 4% of the individuals in a sample had intact arms, whereas 55% of the animals (or 20% of all arms) had one or more 'recent' distal regenerations distinguishable by their smaller diameter. These regenerations presumably account for a large part of the annual growth and somatic production. Stomach content analysis of demersal fish in this area suggests that Amphiura arms form an important part of the diet of the dab, Limanda limanda. Annual consumption of Amphiura arms by dab was estimated to be 0.84 g wet weight-m -2, which is equivalent to 420 arms or 6% of the arm population. Considering the large number of adult animals in the population and regeneration capabilities of the species, the grazing by dab will have only little if any effect on the population.

  19. A theory of the Ka band radar imaging mechanism of a submerged wreck and associated bed forms in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Hennings, Ingo; Herbers, Dagmar

    2010-10-01

    The Ka band radar imaging mechanism of the submerged wreck/sand ribbon of the motor vessel (M/V) Birkenfels in the southern North Sea is investigated by applying the quasi-specular scattering theory and considering the capillary as well as the gravity wave ranges of the wave energy density spectrum. For the imaging of wrecks and other oceanographic and meteorological phenomena at the sea surface it is assumed that quasi-specular scattering becomes dominant at higher radar frequencies like Ka and X band and wind speeds ≥ 7-8 m s-1. Multibeam echo sounder images of the Birkenfels wreck and associated sand ribbons as well as other available environmental in situ data have been analyzed. The formation of sand ribbons at the sea bed and the manifestation of its radar signatures at the water surface are caused by an elliptical vortex or helical flow cell triggered by unidirectional tidal current flow interacting with the wreck. The difference between simulated and measured normalized radar cross section (NRCS) modulation as a function of the space variable is less than 31.6%. Results are presented for NRCS simulations dependent on position for different effective incidence angles, unidirectional current speeds, wind speeds, and relaxation rates. The calculated current gradient or strain rate of the imaging theory has the same order of magnitude as those obtained for marine sand waves. This implies that the responsible hydrodynamic interaction mechanism is able to produce radar signatures of submerged wrecks/sand ribbons and make them visible at the sea surface.

  20. The influence of the North Atlantic Oscillation and El Niño-Southern Oscillation on mean and extreme values of column ozone over the United States

    NASA Astrophysics Data System (ADS)

    Petropavlovskikh, I.; Evans, R.; McConville, G.; Manney, G. L.; Rieder, H. E.

    2014-08-01

    Continuous measurements of total ozone (by Dobson spectrophotometers) across the contiguous United States (US) began in the early 1960s. Here, we analyze temporal and spatial variability and trends in total ozone from the five US sites with long-term records. While similar long-term ozone changes are detected at all five sites, we find differences in the patterns of ozone variability on shorter time scales. In addition to standard evaluation techniques, STL-decomposition methods (Seasonal Trend decomposition of time series based on LOcally wEighted Scatterplot Smoothing, LOESS) are used to address temporal variability and trends in the Dobson data. The LOESS-smoothed trend components show a decline of total ozone between the 1970s and 2000s and a "stabilization" at lower levels in recent years, which is also confirmed by linear trend analysis. Methods from statistical extreme value theory (EVT) are used to characterize days with high and low total ozone (termed EHOs and ELOs, respectively) at each station and to analyze temporal changes in the frequency of ozone extremes and their relationship to dynamical features such as the North Atlantic Oscillation and El Niño Southern Oscillation. A comparison of the "fingerprints" detected in the frequency distribution of the extremes with those for standard metrics (i.e., the mean) shows that more "fingerprints" are found for the extremes, particularly for the positive phase of the NAO, at all five US monitoring sites. Results from the STL-decomposition support the findings of the EVT analysis. Finally, we analyze the relative influence of low and high ozone events on seasonal mean column ozone at each station. The results show that the influence of ELOs and EHOs on seasonal mean column ozone can be as much as ±5%, or about twice as large as the overall long-term decadal ozone trends.

  1. Idetification of the chemical sedimentary protolish of the early Paleoproterozoic banded iron formation from Wuyang area, in the southern margin of the North China Craton

    NASA Astrophysics Data System (ADS)

    Lan, C.; Zhao, T.

    2016-12-01

    The Paleoproterozoic banded iron formation (BIF) from Wuyang area in the southern margin of the North China Craton (NCC) were metamorphosed under granulite facies, and are characterized with an assemblage of clinopyroxene, magnetite and orthopyroxene. Two types of iron ores can be identified on the basis of macro- and micro-textures: banded quartz-clinopyroxene (±othopyroxene) -magnetite ores and massive clinopyroxene-magnetite ores. Two-pyroxene geothermometry indicates that the primary counterparts of these ores have undergone metamorphism with a peak temperature of about 762±9°. Both the banded and massive ores have also similarly BIF-like REE+Y features, and thus are proposed to have all formed from chemical sediments. Similarly, clinopyroxenes from both types have BIF-like rare earth element compositions and are rich in Fe (16-23 wt.% FeOtotoal), further suggesting that they are primary Fe-Mg-Ca-rich chemical sediments during metamorphism. Slight enrichments of TiO2, Al2O3, Zr, Hf, Ta and Th of the Wuyang IF suggest relatively low detritus input. The massive ore have magnetite containing V, Cr and Ti much higher than those of the banded ores, suggesting that they may have undergone stronger secondary alteration possibly related to the intrusion of nearby pyroxenite plutons. Different ores have seawater-like REE+Y patterns with LREE depletions and positive anomalies of La, Eu, and Y, showing that granulite facies metamorphism did not essentially modify the primary compositions of the Wuyang IF deposited from paleo-seawater. Our results suggest less than 0.1% contribution from high-temperature hydrothermal fluids.

  2. The green impact: bacterioplankton response toward a phytoplankton spring bloom in the southern North Sea assessed by comparative metagenomic and metatranscriptomic approaches

    PubMed Central

    Wemheuer, Bernd; Wemheuer, Franziska; Hollensteiner, Jacqueline; Meyer, Frauke-Dorothee; Voget, Sonja; Daniel, Rolf

    2015-01-01

    Phytoplankton blooms exhibit a severe impact on bacterioplankton communities as they change nutrient availabilities and other environmental factors. In the current study, the response of a bacterioplankton community to a Phaeocystis globosa spring bloom was investigated in the southern North Sea. For this purpose, water samples were taken inside and reference samples outside of an algal spring bloom. Structural changes of the bacterioplankton community were assessed by amplicon-based analysis of 16S rRNA genes and transcripts generated from environmental DNA and RNA, respectively. Several marine groups responded to bloom presence. The abundance of the Roseobacter RCA cluster and the SAR92 clade significantly increased in bloom presence in the total and active fraction of the bacterial community. Functional changes were investigated by direct sequencing of environmental DNA and mRNA. The corresponding datasets comprised more than 500 million sequences across all samples. Metatranscriptomic data sets were mapped on representative genomes of abundant marine groups present in the samples and on assembled metagenomic and metatranscriptomic datasets. Differences in gene expression profiles between non-bloom and bloom samples were recorded. The genome-wide gene expression level of Planktomarina temperata, an abundant member of the Roseobacter RCA cluster, was higher inside the bloom. Genes that were differently expressed included transposases, which showed increased expression levels inside the bloom. This might contribute to the adaptation of this organism toward environmental stresses through genome reorganization. In addition, several genes affiliated to the SAR92 clade were significantly upregulated inside the bloom including genes encoding for proteins involved in isoleucine and leucine incorporation. Obtained results provide novel insights into compositional and functional variations of marine bacterioplankton communities as response to a phytoplankton bloom. PMID

  3. The green impact: bacterioplankton response toward a phytoplankton spring bloom in the southern North Sea assessed by comparative metagenomic and metatranscriptomic approaches.

    PubMed

    Wemheuer, Bernd; Wemheuer, Franziska; Hollensteiner, Jacqueline; Meyer, Frauke-Dorothee; Voget, Sonja; Daniel, Rolf

    2015-01-01

    Phytoplankton blooms exhibit a severe impact on bacterioplankton communities as they change nutrient availabilities and other environmental factors. In the current study, the response of a bacterioplankton community to a Phaeocystis globosa spring bloom was investigated in the southern North Sea. For this purpose, water samples were taken inside and reference samples outside of an algal spring bloom. Structural changes of the bacterioplankton community were assessed by amplicon-based analysis of 16S rRNA genes and transcripts generated from environmental DNA and RNA, respectively. Several marine groups responded to bloom presence. The abundance of the Roseobacter RCA cluster and the SAR92 clade significantly increased in bloom presence in the total and active fraction of the bacterial community. Functional changes were investigated by direct sequencing of environmental DNA and mRNA. The corresponding datasets comprised more than 500 million sequences across all samples. Metatranscriptomic data sets were mapped on representative genomes of abundant marine groups present in the samples and on assembled metagenomic and metatranscriptomic datasets. Differences in gene expression profiles between non-bloom and bloom samples were recorded. The genome-wide gene expression level of Planktomarina temperata, an abundant member of the Roseobacter RCA cluster, was higher inside the bloom. Genes that were differently expressed included transposases, which showed increased expression levels inside the bloom. This might contribute to the adaptation of this organism toward environmental stresses through genome reorganization. In addition, several genes affiliated to the SAR92 clade were significantly upregulated inside the bloom including genes encoding for proteins involved in isoleucine and leucine incorporation. Obtained results provide novel insights into compositional and functional variations of marine bacterioplankton communities as response to a phytoplankton bloom.

  4. Shallow groundwater from the far north of Cameroon (southern Lake Chad): revisiting a 20 years old survey of hydrochemistry and stable isotopes

    NASA Astrophysics Data System (ADS)

    Ketchemen-Tandia, Beatrice; Mohammad, Bello; Fouepe, Alain; Ngo Boum, Suzanne; Nlend, Bertil; Garel, Emilie; Celle-Jeanton, Helene; Huneau, Frederic

    2016-04-01

    Two field hydrogeological investigation surveys were conducted in 1992 and 2013 using hydrochemistry and isotope techniques in the far north part of Cameroon which corresponds to the southern part of Lake Chad basin. All of these data relate to groundwater and surface water which were collected at the same places to potentially reveal any temporal variation in the chemical and isotopic characteristics of the water resources. Groundwater show mainly a Ca-HCO3 water type but CaMg-Cl and Na-HCO3 water types can also be found. The groundwater chemistry is resulting from many processes including pure silicate weathering and cation exchange. It is found that the nitrate content after 20 years has increased by an average factor of 6. These high concentrations in nitrate (up to 400 mg/l) are related to local anthropogenic activities and to the very bad conditions of maintaining of wells and boreholes. This pollution is also correlated to the population growth over the past two decades in the region. The isotopic content of groundwater is ranging from -6.87‰ to -0.32‰ for δ18O in 2013 and from -6.03‰ to +0.25‰ in 1992 without noticeable evolution through time. The conventional δD-δ18O diagram indicates that the groundwater has a meteoric origin more or less influenced by evaporation processes. Different processes involving different water sources were highlighted: (i) groundwater which has been affected by evaporation or in communication with evaporated surface waters; (ii) groundwater which is very close to the Global Meteoric Water Line and corresponding to a recent and direct recharge from precipitation; (iii) groundwater which is more depleted corresponding to a mixing between shallow and deep groundwater. This research is partly supported by the RAF7012and RAF7011 project from IAEA.

  5. Validation of impact penetrometer data by cone penetration testing and shallow seismic data within the regional geology of the Southern North Sea

    NASA Astrophysics Data System (ADS)

    Stephan, Sebastian; Kaul, Norbert; Villinger, Heinrich

    2015-06-01

    This study presents the assessment of total cone resistance from in situ deceleration measurements using the Lance Insertion Retardation meter (LIRmeter) in the Southern North Sea. The penetrometer is equipped with a measurement lance that is up to 6 m in length. The aim was to validate LIRmeter data interpretation within the regional geological context by comparison with static velocity cone penetration testing (CPT) and sub-bottom profiles. In total, 13 datasets were taken, in addition to preexisting hydroacoustical and static velocity CPT datasets. The dynamically acquired data were processed and compared to the reference static velocity data. The validation encourages the use of acceleration-based dynamic penetration tests, since a high degree of agreement was demonstrated between independently acquired dynamic and static cone resistance data. Moreover, the results reveal evidence of two successive formations with different geotechnical properties, consistent with existing knowledge on the regional setting. Additionally, there is novel indication of an incised glacial valley with muddy low-permeability sediments extending much further than reported to date, which would necessitate updating of older maps. The main advantage of penetrometer-based deceleration measurements lies in the robustness of the method, and the reliability of the sensors. However, penetration depth is, for dimensioning reasons, limited to the order of a few meters. Additionally, data processing includes the dependency of knowledge about the soil type to correct the dynamic data. These limitations can be satisfactorily outweighed by combination with reference data from static velocity tests, as demonstrated by integrating these data into a soil classification scheme.

  6. Influences of the El Niño Southern Oscillation and the Pacific Decadal Oscillation on the timing of the North American spring

    USGS Publications Warehouse

    McCabe, Gregory J.; Ault, Toby R.; Cook, Benjamin I.; Betancourt, Julio L.; Schwartz, Mark D.

    2012-01-01

    Detrended, modelled first leaf dates for 856 sites across North America for the period 1900–2008 are used to examine how the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) separately and together might influence the timing of spring. Although spring (mean March through April) ENSO and PDO signals are apparent in first leaf dates, the signals are not statistically significant (at a 95% confidence level (p < 0.05)) for most sites. The most significant ENSO/PDO signal in first leaf dates occurs for El Niño and positive PDO conditions. An analysis of the spatial distributions of first leaf dates for separate and combined ENSO/PDO conditions features a northwest–southeast dipole that is significantly (at p < 0.05) different than the distributions for neutral conditions. The nature of the teleconnection between Pacific SST's and first leaf dates is evident in comparable composites for detrended sea level pressure (SLP) in the spring months. During positive ENSO/PDO, there is an anomalous flow of warm air from the southwestern US into the northwestern US and an anomalous northeasterly flow of cold air from polar regions into the eastern and southeastern US. These flow patterns are reversed during negative ENSO/PDO. Although the magnitudes of first leaf date departures are not necessarily significantly related to ENSO and PDO, the spatial patterns of departures are significantly related to ENSO and PDO. These significant relations and the long-lived persistence of SSTs provide a potential tool for forecasting the tendencies for first leaf dates to be early or late.

  7. The Role of the Sedimentary Regime in Shaping the Distribution of Subtidal Sandbank Environments and the Associated Meiofaunal Nematode Communities: An Example from the Southern North Sea

    PubMed Central

    Schratzberger, Michaela; Larcombe, Piers

    2014-01-01

    We combined sediment and faunal data to explore the role of the sedimentary regime in shaping the distribution of subtidal sandbank environments and the associated meiofaunal nematode communities at Broken Bank and Swarte Bank, in the southern North Sea. A variety of sediment transport processes occur in the area, differing in the frequency and magnitude of sediment mobility, and the continuum between erosion, translation and sediment accumulation. The seabed contained a variety of bedforms, including longitudinal furrows, and small to very large sandwaves. The bed sediments were dominated by fine and medium sands, with admixtures of silt and gravel. Based on sedimentary bedforms and grain size analysis, a total of 11 sedimentary facies were delineated, of which 8 were analysed in detail for their relationships with the meiofauna. The sedimentary facies fell clearly into groups of facies, respectively representing high, high-moderate and moderate, and episodic sediment mobility. For those sedimentary facies where daily movement of sediments and bedforms occurred (‘high’ sediment mobility), the resulting spatially homogeneous environments were dominated by an impoverished nematode community comprising small deposit feeders and large predators. Resistance to sediment movement and the ability to exploit alternative food sources were prominent functional features of the successful colonisers. Those facies characterised by relatively infrequent sediment mobility (‘episodic’ and ‘high-moderate and moderate’ sediment mobility) comprised a heterogeneous suite of benthic habitats, containing taxonomically and functionally diverse assemblages of nematodes of various sizes, feeding types and reproductive potential. Faunal distribution patterns here indicated trade-offs between the resistance to sediment movement, environmental tolerance and competitive abilities. Our focus on diverse assemblages of organisms with high turnover times, inhabiting highly dynamic

  8. Biogeochemical plant-soil interaction: variable element composition in leaves of four plant species collected along a south-north transect at the southern tip of Norway.

    PubMed

    Reimann, C; Englmaier, P; Fabian, K; Gough, L; Lamothe, P; Smith, D

    2015-02-15

    Leaves from four different plant species (birch, willow, juniper, and heather) together with samples of the soil O and C horizons were collected at 44-46 sites along a south-to-north transect extending inland for 200 km from the southern tip of Norway. The transect covers one of the steepest vegetation gradients on Earth, crossing six vegetation zones. Juniper and heather are evergreen, and preferably exclude potentially toxic elements to avoid their accumulation in assimilating tissues, birch and willow shed their leaves in autumn together with the load of potentially toxic elements, and thus can tolerate the uptake of such elements. The plant leaves show the highest concentrations for B, Ca, K, Mg, Mn, P, Rb and S. In the soil O-horizon Ag, Au, As, Bi, Cu, Ge, Hg, In, Pb, Sb, Se, Sn, Te and W are enriched with respect to the C-horizon, whilst Mn and Rb are depleted. Cadmium, Sr and Zn are enriched in willow and Cs, Na and Tl in heather. In terms of concentration gradients from the coast inland, two different patterns are detected: 1) short range with an almost exponential decrease of concentrations from the coast, which appears to be typical for seaspray-related element input, and 2) long range with an almost linear decrease of concentrations with distance from the coast. These patterns differ among the four species, even for one and the same element. Inter-element correlation is different from material to material. Along the transect each of the different plants at the same site individually adapts to the available element combination. High linear correlations in the plants occur between the lanthanides (La, Ce, Y), and interestingly, between P and Ti. The plant/soil system appears highly non-linear and self-regulated.

  9. The seroprevalence of avipoxvirus and its association with avian malaria (Plasmodium spp.) infection in introduced passerine birds in the southern regions of the North Island of New Zealand.

    PubMed

    Ha, H J; Banda, M; Alley, M R; Howe, L; Gartrell, B D

    2013-03-01

    Blood samples were collected from 65 free-ranging birds from six species in the southern North Island of New Zealand. Sera from the birds were tested for the presence of avipoxvirus (APV) antibodies by enzyme-linked immunosorbent assay (ELISA), and blood cells from 55 birds were also tested for Plasmodium spp. by PCR. Forty-five birds (69.2%) tested seropositive to APV. Song thrushes (Turdus philomelos) presented the highest seroprevalence at 100% (4/4), followed by Eurasian blackbirds (Turdus merula) (96.86%, 31/32), chaffinches (Fringilla coelebs) (54.55%, 6/11), starlings (Sturnus vulgaris) (25%, 3/12), greenfinches (Carduelis chloris) (25%, 1/4), and European goldfinches (Carduelis carduelis) (0%, 0/2). Plasmodium spp. DNA was detected in 15/55 birds (27.3%), including 11 Eurasian blackbirds, one song thrush, and three starlings. Eight Eurasian blackbird isolates (73%) grouped within the subgenus Novyella. Two Eurasian blackbird isolates and the song thrush isolate clustered within a different group with previously reported lineages LINN1 and AFTRU5. In addition, all three starling isolates clustered within the well-characterized lineage Plasmodium (Huffia) elongatum GRW06. All Plasmodium-positive Eurasian blackbirds and the song thrush were seropositive to APV, whereas only 67% of Plasmodium-positive starlings showed evidence of previous exposure to APV. A significant relationship between birds seropositive to APV and birds infected by Plasmodium spp. was observed (chi2 = 5.69, df = 1, P = 0.0086). To the authors' knowledge this is the first report describing the seroprevalence of APV and its association with Plasmodium spp. infection in introduced bird species in New Zealand.

  10. Concentrations and modes of occurrence of trace elements in the Late Permian coals from the Puan Coalfield, southwestern Guizhou, China.

    PubMed

    Yang, Jianye

    2006-12-01

    The concentration, mode of occurrence, and origin of trace elements in the Late Permian coals from the Puan Coalfield, southwestern Guizhou, China, were examined using inductively coupled plasma-mass spectrometry (ICP-MS), X-ray fluorescence (XRF), cold-vapor atomic absorption spectrometry (CV-AAS), ion-selective electrode method (ISE), sequential chemical extraction procedure (SCEP), scanning electron microscopy equipped with energy-dispersive X-ray (SEM-EDX), and optical microscope. Results show that minerals in the No. 2 Coal from the Puan Coalfield were mainly made up of epigenetic pyrite of low-temperature hydrothermal fluid origin and kaolinite of detrital terrigenous origin. Elements including As (36.9 microg/g), Cd (10.2 microg/g), Cr (167.3 microg/g), Cu (365.4 microg/g), Hg (2.82 microg/g), Mo (92.6 microg/g), Ni (82.6 microg/g), Pb (184.6 microg/g), Se (6.23 microg/g), Zn (242.3 microg/g), and U (132.7 microg/g) are significantly enriched in the No. 2 Coal from the Puan Coalfield. However, concentrations of trace elements in the other four coals, the No. 1, No. 8, No. 11, and No. 18 Coals, were close to the usual ranges found for Guizhou of China, China, and USA. Results of SEM-EDX and SCEP showed that As, Cd, Hg, Mo, Ni, Pb, and Zn occur mainly in veined pyrite, while Cr, Cu, and U distribute mainly in kaolinite, indicating that the low-temperature hydrothermal fluid and detrital materials of terrigenous origin are the main contributors to the enrichment of these trace elements in the No. 2 Coal.

  11. Abundances and isotopic compositions of rhenium and osmium in pyrite samples from the Huaibei coalfield, Anhui, China

    USGS Publications Warehouse

    Liu, Gaisheng; Chou, C.-L.; Peng, Z.; Yang, G.

    2008-01-01

    Two pyrite samples from the Shihezi Formation (Lower Permian), Huaibei coalfield, Anhui, China, have been analyzed for abundances and isotopic compositions of rhenium and osmium using negative thermal ion mass spectrometry. The Re-Os ages of the pyrites are 64.4 and 226 Ma, which are younger than the formation age of the coal seam. The pyrite samples may consist of pyrite formed at various stages during the history of coal formation. The ??Osvalues of the two pyrite samples are +17 and +18, respectively. Such high ??Osvalues are reported for the first time for recycles crustal materials from a sedimentary basin. ?? Springer-Verlag 2007.

  12. Map showing selected surface-water data for the Alton-Kolob coal-fields area, Utah

    USGS Publications Warehouse

    Price, Don

    1982-01-01

    This is one of a series of maps that describe the geology and related natural resources of the Alton-Kolob coal-fields area, Utah. Streamflow records used to compile the map and the following table were collected by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights, and the Utah Department of Transportation. The principal runoff-producing areas were delineated form a work map (scale 1:250,000) compiled to estimate water yields in Utah (Bagley and others, 1964).

  13. Geochemistry of trace elements in coals from the Zhuji Mine, Huainan Coalfield, Anhui, China

    USGS Publications Warehouse

    Sun, R.; Liu, Gaisheng; Zheng, Lingyun; Chou, C.-L.

    2010-01-01

    The abundances of nine major elements and thirty-eight trace elements in 520 samples of low sulfur coals from the Zhuji Mine, Huainan Coalfield, Anhui, China, were determined. Samples were mainly collected from 10 minable coal seams of 29 boreholes during exploration. The B content in coals shows that the influence of brackish water decreased toward the top of coal seams; marine transgression and regression occurred frequently in the Lower Shihezi Formation. A wide range of elemental abundances is found. Weighted means of Na, K, Fe, P, Be, B, Co, Ni, Cr, Se, Sb, Ba, and Bi abundances in Zhuji coals are higher, and the remainder elements are either lower or equal to the average values of elements in coals of northern China. Compared to the Chinese coals, the Zhuji coals are higher in Na, K, Be, B, Cr, Co, Se, Sn, Sb, and Bi, but lower in Ti, P, Li, V and Zn. The Zhuji coals are lower only in S, P, V and Zn than average U.S. and world coals. Potassium, Mg, Ca, Mn, Sr, As, Se, Sb and light rare earth elements (LREE) had a tendency to be enriched in thicker coal seams, whereas Fe, Ti, P, V, Co, Ni, Y, Mo, Pb and heavy rare earth elements (HREE) were inclined to concentrate in thinner coal seams. The enrichment of some elements in the Shanxi or Upper Shihezi Formations is related to their depositional environments. The elements are classified into three groups based on their stratigraphic distributions from coal seams 3 to 11-2, and the characteristics of each group are discussed. Lateral distributions of selected elements are also investigated. The correlation coefficients of elemental abundances with ash content show that the elements may be classified into four groups related to modes of occurrence of these elements. ?? 2009 Elsevier B.V. All rights reserved.

  14. Assessment of environmental soil quality around Sonepur Bazari mine of Raniganj coalfield, India

    NASA Astrophysics Data System (ADS)

    Masto, R. E.; Sheik, S.; Nehru, G.; Selvi, V. A.; George, J.; Ram, L. C.

    2015-07-01

    Assessment of soil quality is one of the key parameters for evaluation of environmental contamination in the mining ecosystem. To investigate the effect of coal mining on soil quality, opencast and underground mining sites were selected in the Raniganj coalfield area, India. The physical, chemical, and biological parameters of the soils, and trace metals and PAHs (polycyclic aromatic hydrocarbons) in the soils were evaluated. Soil dehydrogenase (+79 %) and fluorescein (+32 %) activities were significantly higher in underground mine (UGM) soil, whereas peroxidase activity (+57 %) was higher in opencast mine (OCM) soil. Content of As, Be, Co, Cr, Cu, Mn, Ni, and Pb was significantly higher in OCM soil, whereas Cd was higher in UGM. In general, the PAHs contents were higher in UGM soils, probably due to the natural coal burning at these sites. The observed values for the above properties were converted into a unitless score (0-1.00) and the scores were integrated into an environmental soil quality index (ESQI). In the unscreened index (ESQI-1) all the soil parameters were included and the results showed that the quality of the soil was better for UGM (0.539) than the OCM (0.511) soils. Principal component analysis was employed to derive ESQI-2 and accordingly, total PAHs, loss on ignition, bulk density, Be, Co, Cr, Ni, Pb, and microbial quotient (respiration: microbial biomass ratio) were found to be the most critical properties. The ESQI-2 was also higher for soils near UGM (+10.1 %). The observed indicators and the ESQI results revealed that soil quality assessment for these coal mining soils is largely depended on soil PAHs and potentially toxic trace metals. The proposed ESQI may be further refined by incorporating specific parameters related to human exposure risks and exposure pathways.

  15. A study of mining-induced subsidence in Hebi coalfield based on D-InSAR

    NASA Astrophysics Data System (ADS)

    Ma, Chao

    2014-11-01

    The aim of obtaining a continuous space distribution of mining-induced subsidence in a large scale, damage intensity, and its dynamic evolution, furthermore understanding the rule of the subsidence, is extracts finally the surface movement parameters of the mining-induced subsidence. Using 9 issues of ENVISAT ASAR data over 2009 year and by both of DInSAR processing algorithms, an atmospheric effect can eliminate and real subsidence region can be determined by a cumulative phase 2 PASS D-InSAR, and a temporal decoherence effect can be reduced and each stage deformation can be extracted by an adjacent phase 2 PASS D-InSAR. Results are as follows: (1) 8 phase variation regions according with the criterion of mining subsidence are extracted from 70 phase variation regions with the two methods of D-InSAR. (2) 16 main profiles (along with the strike, dip) of subsidence contained in 8 typical subsidence basins are obtained. Annual maximum subsidence reaches -210.0mm during the period of image acquisitions, from Jan. to Sep. 2009, the maximum rate is ±1.2 mm/d, and the average daily subsidence rate is ±0.60mm/d. (3) Sampling the minimum Standard Deviation (SD) is ± 4.3 mm, maximum SD is ± 8.1mm, and the total SD Mean is ± 5.9mm. Root Mean Square Error (RMSE) of data processing is ± 0.41 mm, the maximum RMSE is ± 0.74 mm, total average RMSE of observations is ± 0.55mm. The monitoring accuracy is self-consistent at sub-centimeter level, and it can reveal the rule of mining subsidence and extract partly parameters of mining damage. The result presents also that mine surface by the impact of mining activities are frequent and severe, deterioration of surface stability, and the risk of collapse, slip or mudslides is higher than outside coalfield.

  16. [A field experiment of runoff and sediment yielding processes from residues in Shenfu-Dongsheng Coalfield].

    PubMed

    Li, Jian-Ming; Wang, Wen-Long; Wang, Zhen; Luo, Ting; Li, Hong-Wei; Jin, Jian

    2013-12-01

    The processes of runoff and sediment yields from and the benefits of water and sediment reductions by the residues produced in the Shenfu-Dongsheng Coalfield were investigated by a simulated field rainfall experiment. The runoff generation time generally presented a decreasing trend with increasing rainfall intensity, but varied widely with the change of residue compositions. Runoff from the slag reached a steady velocity faster than that from the spoil, and the average velocities of runoff from the residues were gradually decreased in the spoil, the slag with more sand and less stone, and the slag with less sand and more stone. Runoff rates for the residues reached a steady rate 6 min after runoff generation, and were significantly correlated with the rainfall intensities. Erosion on the residues mainly occurred in the first 6 min after runoff generation. Average sediment concentrations in the first 6 min were 0.43-4.27 times of those thereafter for the spoil, and 1.43-54.93 times for the slag. The runoff volume was a linear function of the rainfall intensity for the spoil and the slag with more sand and less stone, and was a power function of rainfall intensity for the slag with less sand and more stone. The relationships between single erosion and rainfall intensity for the spoil and the slag with less sand and more stone can be described by exponential and power functions, respectively. For the spoil, the erosion rate was a linear function of the runoff volume. When fish-scale pits and vegetation coverage were adopted on the surface of the slag, the generation of runoff lagged 24 min behind initial rainfall applications at intensities of 1.0 and 1.5 mm x min(-1), and the runoff and sediment yields were reduced by 29.5%-52.9% and 85.7%-97.9%, respectively.

  17. The research and implementation of coalfield spontaneous combustion of carbon emission WebGIS based on Silverlight and ArcGIS server

    NASA Astrophysics Data System (ADS)

    Zhu, Z.; Bi, J.; Wang, X.; Zhu, W.

    2014-02-01

    As an important sub-topic of the natural process of carbon emission data public information platform construction, coalfield spontaneous combustion of carbon emission WebGIS system has become an important study object. In connection with data features of coalfield spontaneous combustion carbon emissions (i.e. a wide range of data, which is rich and complex) and the geospatial characteristics, data is divided into attribute data and spatial data. Based on full analysis of the data, completed the detailed design of the Oracle database and stored on the Oracle database. Through Silverlight rich client technology and the expansion of WCF services, achieved the attribute data of web dynamic query, retrieval, statistical, analysis and other functions. For spatial data, we take advantage of ArcGIS Server and Silverlight-based API to invoke GIS server background published map services, GP services, Image services and other services, implemented coalfield spontaneous combustion of remote sensing image data and web map data display, data analysis, thematic map production. The study found that the Silverlight technology, based on rich client and object-oriented framework for WCF service, can efficiently constructed a WebGIS system. And then, combined with ArcGIS Silverlight API to achieve interactive query attribute data and spatial data of coalfield spontaneous emmission, can greatly improve the performance of WebGIS system. At the same time, it provided a strong guarantee for the construction of public information on China's carbon emission data.

  18. Map showing general availability of ground water in the Alton-Kolob coal-fields area, Utah

    USGS Publications Warehouse

    Price, Don

    1982-01-01

    This is one of a series of maps that describes the geology and related natural resources of the Alton-Kolob coal-fields area, Utah. Shown on this map is the general availability of ground water as indicated by potential yields of individual wells and expected depth to water in wells. Most data used to compile this map were collected by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources Division of Water Rights. Other sources of data included the U.S. Geological Survey 7½- and 15-minute topographic quadrangle maps, unpublished reports of field evaluations of potential shock-watering sites by U.S. Geological Survey personnel, and the geologic map of Utah (Stokes, 1964).This map is very generalized and is intended chiefly for planning purposes. It should be used with discretion. For more detailed information about the availability of ground water in various parts of the map area the reader is referred to the following reports: Thomas and Taylor (1946); Marine (1963); Sandberg (1963, 1966); Carpenter, Robinson, and Bjorklund (1964, 1967); Feltis (1966); Goode (1964, 1966); Cordova, Sandberg, and McConkie (1972); Cordova (1978, 1981); and Bjorklund, Sumison, and Sandberg (1977, 1978). For a general description of the chemical quality of ground water in the Alton-Kolob coal-fields area the reader is referred to Price (1981).

  19. Towards "a different kind of beauty": responses to coal-based pollution in the Witbank coalfield between 1903 and 1948.

    PubMed

    Singer, Michal

    2011-01-01

    This article assesses the changing conceptions of the environmental impact of South African coal mining in the first half of the twentieth century, with special reference to the Witbank coalfield in the Mpumalanga province of South Africa. The anticipated development of the emerging coal town of Witbank was founded on the growing demand for coal. As Witbank's local landscape became visibly scarred, coal-based pollution was continually challenged and redefined. In an attempt to market electricity, and appease the doubts of potential consumers, attempts were made by Escom to romanticise features of Witbank's industrialised environment. Once mines were decommissioned, they were abandoned. Coal production increased dramatically during the Second World War, which provided an economic windfall for the local electrical, steel and chemical industries, placing undue pressure on the coal industry to step up production. The severe damage caused by coal mining during this period resulted in the ecological devastation of affected landscapes. The findings of an inter-departmental committee established to conduct research during the mid-1940s revealed the gravity of coal-based pollution, and set a precedent in the way that the state conceived of the impact of industry and mining. The report of this committee was completed in the wake of the war, by which time the Witbank coalfield had become one of the most heavily polluted regions of South Africa.

  20. InSAR Monitoring OF Landslides In Britain: BGS' Feasibility Map And First ISBAS Studies Over The South Wales Coalfield

    NASA Astrophysics Data System (ADS)

    Cigna, F.; Bateson, L.; Dashwood, C.; Jordan, C. J.; Sowter, A.; Boon, D.

    2013-12-01

    InSAR is an accepted method for monitoring ground motion, however its applicability in non-urban areas is generally limited except for rocky terrains. This paper investigates a new method for deriving improved results outside the urban environment. Topographic distortions to the ERS-1/2 and ENVISAT SAR acquisition modes are simulated based on high resolution DTMs of the landmass of Britain. Persistent Scatterers (PS) densities are predicted by calibrating the CORINE Land Cover 2006 dataset using PS data available via the ESA Terrafirma and EC FP7 PanGeo projects. The InSAR feasibility to monitor land motions is discussed for the South Wales Coalfield, and the Intermittent Small Baseline Subset (ISBAS) technique is tested over the Coalfield using 55 ERS-1/2 images (1992-1999). With unprecedented target coverage, ISBAS reveals up to 1cm/yr uplift in areas of former coal mining, likely associated with groundwater rebound following cessation of mine water pumping.

  1. Permian, Jurassic and Early Cretaceous palynofloral assemblages from subsurface sedimentary rocks in Chuperbhita Coalfield, Rajmahal Basin, India.

    PubMed

    Tripathi, A

    2001-04-01

    The results of a palynological analysis of the sedimentary sequence of Borehole RCH-151, Chuperbhita Coalfield, Rajmahal Basin, Bihar are presented here. The borehole penetrated the Rajmahal Formation (comprising two traps sandwiching an intertrappean bed), the thinly represented Dubrajpur Formation and in its lower part, the Coal Measures. The coal-bearing interval is associated with Scheuringipollenites barakarensis, Faunipollenites varius, Densipollenites indicus, Gondisporites raniganjensis and Densipollenites magnicorpus Assemblage Zones. The presence of these biostratigraphic units indicates correlation with the Barakar Formation (Early Permian) and the Barren Measures and Raniganj Formations (both Late Permian). This is the first record, in the Chuperbhita Coalfield, of Late Permian strata, which appear to represent a condensed sequence. Prior to the present study, the Permian succession was thought to have been associated entirely with the Barakar Formation. The overlying Dubrajpur Formation yielded a distinct spore-pollen assemblage (in association with the first report of dinoflagellate, Phallocysta), which is assigned to the newly identified Callialasporites turbatus palynozone of latest Early to early Middle Jurassic age. The diverse spore-pollen flora of the intertrappean bed (Rajmahal Formation) incorporates several age marker taxa, viz. Undulatisporites, Leptolepidites, Klukisporites, Ruffordiaspora, and Coptospora. The assemblages from intertrappean beds are correlated with the Ruffordiaspora australiensis palynozone of Australia. Thus the palynodating indicates Permian, latest Early to early Mid-Jurassic and Early Cretaceous age for the strata studied. This is the first record of definite Jurassic microfossils from the non-marine sequence of Rajmahal Basin, India.

  2. Differential modulation of eastern oyster ( Crassostrea virginica) disease parasites by the El-Niño-Southern Oscillation and the North Atlantic Oscillation

    NASA Astrophysics Data System (ADS)

    Soniat, Thomas M.; Hofmann, Eileen E.; Klinck, John M.; Powell, Eric N.

    2009-02-01

    The eastern oyster ( Crassostrea virginica) is affected by two protozoan parasites, Perkinsus marinus which causes Dermo disease and Haplosporidium nelsoni which causes MSX (Multinucleated Sphere Unknown) disease. Both diseases are largely controlled by water temperature and salinity and thus are potentially sensitive to climate variations resulting from the El Niño-Southern Oscillation (ENSO), which influences climate along the Gulf of Mexico coast, and the North Atlantic Oscillation (NAO), which influences climate along the Atlantic coast of the United States. In this study, a 10-year time series of temperature and salinity and P. marinus infection intensity for a site in Louisiana on the Gulf of Mexico coast and a 52-year time series of air temperature and freshwater inflow and oyster mortality from Delaware Bay on the Atlantic coast of the United States were analyzed to determine patterns in disease and disease-induced mortality in C. virginica populations that resulted from ENSO and NAO climate variations. Wavelet analysis was used to decompose the environmental, disease infection intensity and oyster mortality time series into a time-frequency space to determine the dominant modes of variability and the time variability of the modes. For the Louisiana site, salinity and Dermo disease infection intensity are correlated at a periodicity of 4 years, which corresponds to ENSO. The influence of ENSO on Dermo disease along the Gulf of Mexico is through its effect on salinity, with high salinity, which occurs during the La Niña phase of ENSO at this location, favoring parasite proliferation. For the Delaware Bay site, the primary correlation was between temperature and oyster mortality, with a periodicity of 8 years, which corresponds to the NAO. Warmer temperatures, which occur during the positive phase of the NAO, favor the parasites causing increased oyster mortality. Thus, disease prevalence and intensity in C. virginica populations along the Gulf of Mexico

  3. Mineralogical and microfabric characteristics of magnetite in the Wuyang Precambrian BIFs, southern North China Craton: Implications for genesis and depositional processes of the associated BIFs

    NASA Astrophysics Data System (ADS)

    Li, Hongzhong; Zhai, Mingguo; Zhang, Lianchang; Yang, Zhijun; Kapsiotis, Argyrios; Zhou, Yongzhang; He, Junguo; Wang, Changle; Liang, Jin

    2014-11-01

    Precambrian Banded Iron Formations (BIFs) are widely distributed in the North China Craton (NCC). Among them, the Wuyang BIFs located in the southern margin of NCC occur in the Late Archaean Tieshanmiao Formation and can be subdivided in two different sub-types: (i) quartz-magnetite BIFs (QMB), consisting of magnetite, fine-microcrystalline quartz and minor calcite and (ii) pyroxene-magnetite BIFs (PMB), composed of pyroxene, fine-microcrystalline quartz and subordinate feldspars. Both sub-types display apparent discrepancies in terms of petrography and mineral composition. As shown in Electron BackScattered Diffraction (EBSD) images and micrographs, magnetite grains from the QMB range in size from tens up to hundreds of μm, whereas magnetite crystals from the PMB can be up to a few tens of μm across. The X-ray diffraction (XRD) structural data indicate that magnetite from both BIF sub-types is equiaxed (cubic) and was generated by sedimentary metamorphic processes. The cell parameters of magnetite in the QMB are a = b = c = 8.396 Å and Z = 8, which deviate slightly from these of magnetite in the PMB: a = b = c = 8.394 Å and Z = 8. The analytical results of Raman spectroscopy analysis revealed micro-structural signatures of both magnetite (Raman shifts near 552 cm-1 and 673 cm-1) and hematite (Raman shifts near 227 cm-1, 295 cm-1 and 413 cm-1). In magnetite from both QMB and PMB, the crystallinity degree is similar for magnetite micro-structures but varies significantly for hematite micro-structures. Oxygen fugacity (fO2) conditions fluctuated during the recrystallization of magnetite in the QMB, whereas no evident variation of fO2 occurred during the formation of magnetite in the PMB. Analytical results of laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) show that the Si, Al and Mg abundances are higher in magnetite from the QMB, whereas the Ti and Mn contents are more elevated in magnetite from the PMB. Magnetite composition also

  4. Cloud filling of ocean colour and sea surface temperature remote sensing products over the Southern North Sea by the Data Interpolating Empirical Orthogonal Functions methodology

    NASA Astrophysics Data System (ADS)

    Sirjacobs, Damien; Alvera-Azcárate, Aida; Barth, Alexander; Lacroix, Geneviève; Park, YoungJe; Nechad, Bouchra; Ruddick, Kevin; Beckers, Jean-Marie

    2011-01-01

    Optical remote sensing data is now being used systematically for marine ecosystem applications, such as the forcing of biological models and the operational detection of harmful algae blooms. However, applications are hampered by the incompleteness of imagery and by some quality problems. The Data Interpolating Empirical Orthogonal Functions methodology (DINEOF) allows calculation of missing data in geophysical datasets without requiring a priori knowledge about statistics of the full dataset and has previously been applied to SST reconstructions. This study demonstrates the reconstruction of complete space-time information for 4 years of surface chlorophyll a (CHL), total suspended matter (TSM) and sea surface temperature (SST) over the Southern North Sea (SNS) and English Channel (EC). Optimal reconstructions were obtained when synthesising the original signal into 8 modes for MERIS CHL and into 18 modes for MERIS TSM. Despite the very high proportion of missing data (70%), the variability of original signals explained by the EOF synthesis reached 93.5% for CHL and 97.2% for TSM. For the MODIS TSM dataset, 97.5% of the original variability of the signal was synthesised into 14 modes. The MODIS SST dataset could be synthesised into 13 modes explaining 98% of the input signal variability. Validation of the method is achieved for 3 dates below 2 artificial clouds, by comparing reconstructed data with excluded input information. Complete weekly and monthly averaged climatologies, suitable for use with ecosystem models, were derived from regular daily reconstructions. Error maps associated with every reconstruction were produced according to Beckers et al. (2006). Embedded in this error calculation scheme, a methodology was implemented to produce maps of outliers, allowing identification of unusual or suspicious data points compared to the global dynamics of the dataset. Various algorithm artefacts were associated with high values in the outlier maps (undetected cloud

  5. CCN in the marine environment: Results from two intensive measurement campaigns - The Eastern North Atlantic (Mace Head) and The Southern Ocean (PEGASO cruise)

    NASA Astrophysics Data System (ADS)

    Ovadnevaite, Jurgita; Fossum, Kirsten; Ceburnis, Darius; Dall'Osto, Manuel; Simo, Rafel; O'Dowd, Colin

    2016-04-01

    Marine aerosol occurring in cloud condensation nucleus (CCN) sizes suggest that it may contribute notably to the CCN population [1, 2], but further cloud droplet number concentration would strongly depend on the ambient (cloud) conditions, such as available water content, supersaturation and competition between the CCN of different composition [3]. Since the global importance of marine aerosol particles to the cloud formation was postulated several decades ago [4], it has progressed from the evaluation of the nss-sulphate and sea salt effects to an acknowledgement of the significant role of organic aerosol [5]. It was demonstrated that primary marine organics, despite its hydrophobic nature, can possess the high CCN activation efficiency, resulting in the efficient cloud formation [6]. Results from two intensive measurement campaigns in The Eastern North Atlantic (Mace Head) and The Southern Ocean (PEGASO cruise) is presented here with the main focus on ssCCN dependence on aerosol chemical composition and, especially, origin and sources of marine organic. We investigate the activation of sea spray composed of the sea salt and externally mixed with nss-sulphate as well as the sea spray highly enriched in organics, stressing the importance of the latter to the formation of the cloud droplets. We also explore the suitability of existing theories to explain the marine aerosol activation to CCN. Acknowledgments The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) project BACCHUS under grant agreement n° 603445; Spanish Ministry of Economy and Competitiveness (MINECO) as part of the PEGASO (Ref.: CTM2012-37615) and BIO-NUC (Ref.: CGL2013-49020-R); HEA-PRTLI4;EC ACTRIS. [1] Meskhidze & Nenes (2006) Science 314, 1419-1423. [2] Sorooshian et al. (2009) Global Biogeochemical Cycles 23, GB4007. [3] O'Dowd et al. (1999) Quarterly Journal of the Royal Meteorological Society 125, 1295-1313. [4] Charlson

  6. Textures, trace elements, and Pb isotopes of sulfides from the Haopinggou vein deposit, southern North China Craton: implications for discrete Au and Ag-Pb-Zn mineralization

    NASA Astrophysics Data System (ADS)

    Li, Zhan-Ke; Li, Jian-Wei; Cooke, David R.; Danyushevsky, Leonid; Zhang, Lejun; O'Brien, Hugh; Lahaye, Yann; Zhang, Wen; Xu, Hai-Jun

    2016-12-01

    The Haopinggou deposit in the Xiong'ershan district, southern margin of the North China Craton, comprises numerous Au and Ag-Pb-Zn veins hosted in metamorphic rocks of the Late Archean to early Paleoproterozoic Taihua Group. Two stages of mineralization have been recognized: Stage 1 pyrite-quartz veins and Stage 2 Pb-Zn-sulfide veins. Some pyrite-quartz veins are surrounded or cut by Pb-Zn-sulfide veins, others occur as independent veins. Six generations of pyrite have been identified at Haopinggou: Py1 to Py3 in Stage 1 and Py4 to Py6 in Stage 2. Pyrites from Stage 1 are enriched in Au, As, Co, Ni, and Bi, whereas Stage 2 pyrites contain higher Ag, Pb, Zn, Sn, and Sb. Invisible Au mostly occurs as lattice-bound gold in Py2 (up to 92 ppm Au) and Py3 (up to 127 ppm Au) and has a close relationship with As. Native Au grains are also present in Py3 and likely resulted from mobilization and reprecipitation of the invisible Au previously locked in the precursor pyrite. This view is supported by extensive plastic deformation in Stage 1 pyrite as revealed by electron backscatter diffraction analysis. In Stage 2, Ag is mostly present as lattice-bound silver closely associated with Sb in galena (up to 798 ppm Ag). A variety of silver minerals are also present as inclusions within galena or as interstitial grains. These silver minerals were likely formed via Ag-Cu exchange reaction between tetrahedrite and galena or represent exsolution from galena due to a temperature decrease. Pb isotopic compositions differ remarkably between Stage 1 and Stage 2 sulfides, indicating different sources of lead. Pb in Stage 2 Pb-Zn-sulfide veins is consistent with the Haopinggou porphyry close to the veins. The field, textural, compositional, and lead isotopic data led us to conclude that the early gold-bearing pyrite-quartz veins and late silver-bearing Pb-Zn-sulfide veins likely formed from distinct fluid systems related to discrete mineralization events. Our study suggests that Au and Ag

  7. Amino acid racemization analysis (AAR) as a successful tool for dating Holocene coastal sediments: Stratigraphy of a barrier island spit (Southern Sylt/North Sea)

    NASA Astrophysics Data System (ADS)

    Tillmann, Tanja; Ziehe, Daniel

    2014-05-01

    Dating of Holocene sediments in shallow coastal areas of the German North Sea by conventional techniques is commonly problematic. In particular the marine reservoir effect of radiocarbon means that radiocarbon dating cannot be applied to sediments younger than about 400 years. Amino acid racemization dating (AAR) is a viable alternative for dating young sediments. The method is based on the determination of ratios of D and L amino acid enantiomers in organic matrices of biogenic carbonates. In this study we use AAR as a tool for dating Holocene barrier islands sediments. Based on an AAR derived chronological framework we develop a model of barrier spit accretion which describes the interaction between extreme events, fair weather coastal processes and sedimentary development that constrains the major episodes of barrier island evolution. The stratigraphy was defined using ground-penetrating radar (GPR) surveys complemented by sedimentological coring data. The stratigraphy is then conceptualised in a AAR chronostratigraphic framework to define a chronological order and allow the development of a stratigraphic model of the evolution of Southern Sylt. The AAR data provide high temporal resolution and have been used for dating stages of barrier spit accretion. The time lines are marked as storm surge generated erosion unconformities in the stratigraphic profile. Individual shells and shell fragments of Cerastoderma edule, Mya arenaria, Mytilus edulis and Scrobicularia plana have been accumulated by short-term storm events as shell layers associated with the erosion unconformities and have been dated by AAR. Time lines reveal that the barrier spit accretion occurred episodically, and is dependant on the provided rate of sand delivery. The general trend is that sequences young to the. South. The AAR derived time lines have been verified and correlated by historic maps and sea charts. It is apparent that spit enlargement at this site increased significantly during the

  8. Characterization and origin of the Taishanmiao aluminous A-type granites: implications for Early Cretaceous lithospheric thinning at the southern margin of the North China Craton

    NASA Astrophysics Data System (ADS)

    Wang, Changming; Chen, Liang; Bagas, Leon; Lu, Yongjun; He, Xinyu; Lai, Xiangru

    2016-07-01

    Late Mesozoic magmatic rocks from the Taishanmiao Batholith were collected for LA-ICP-MS dating, Sr-Nd-Hf isotope systematics, and whole-rock major and trace element geochemistry to help understand the nature of collisional and extensional events along the southern margin of the North China Craton. The batholith consists of three texturally distinguishable phases of a 125 ± 1 Ma medium- to coarse-grained syenogranite, a 121 ± 1 Ma fine- to medium-grained syenogranite, and a 113 ± 1 Ma porphyritic monzogranite. Most of the units in the batholith are syenogranitic in composition with high levels of silica (70-78 wt% SiO2), alkalis (8.0-8.6 wt% Na2O + K2O), Fe* (FeOT/(FeOT + MgO) = 0.76-0.90), and depletion in CaO (0.34-1.37 wt%), MgO (0.12-0.52 wt%), TiO2 (0.09-0.40 wt%), and A/CNK (Al2O3/(Na2O + K2O + CaO)) molar ratios of 1.00-1.11. All samples have high proportions of Ga, Nb, Zr, Ga/Al, and REE, and depletions in Ba, Sr, Eu, and compatible elements, indicating that the batholith consists of A-type granites. The zircon saturation temperature for these units yields a mean value of 890 °C, and zircons with Early Cretaceous magmatic ages have ɛNd( t) values of -14.0 to -12.0, ɛHf( t) values ranging from -18.7 to -2.1, and corresponding Hf model ages of 2339-1282 Ma. These geochemical and isotopic characteristics allowed us to conclude that the primary magma for the Taishanmiao Batholith originated from partial melting of Precambrian crustal rocks in the medium-lower crust. However, the high Nb and Ta contents and low normalized Nb/Ta values for the Taishanmiao granites are due to fractionation in Nb- and Ta-rich amphibole (or biotite). It is further proposed that these aluminous A-type granites were generated in an extensional tectonic setting during the Early Cretaceous, which was induced by lithospheric thinning and asthenospheric upwelling beneath eastern China toward the Paleo-Pacific Plate.

  9. Architecture, Kinematics, and Development of Widespread Late Oligocene to Early Miocene East-Northeast and West-Northwest Trending Extensional Basins during North-South Extension in the Central and Southern Walker Lane, Western Great Basin

    NASA Astrophysics Data System (ADS)

    Kerstetter, S. R.; Katopody, D. T.; Oldow, J. S.

    2016-12-01

    In the central and southern Walker Lane, a network of seven east-northeast and west-northwest trending half-grabens, spanning an area of 4000 km2, controlled the spatial distribution and thickness of late Oligocene to early Miocene volcanic and volcaniclastic rocks. The basins range from 10 to 20 km long, are 4 to 7 km wide, and from 0.5 to 1.5 km deep. Internally, the basins are segmented by north-northeast and north-northwest striking transfer faults that accommodated along-axis changes in basin geometry and across-axis dog-leg steps of up to 15 km. The basin-fill consists of synextensional rhyolite tuff, andesite, and volcaniclastic rocks that form asymmetric stratal wedges that thicken to the north and south into basin-bounding faults. In several locations, the bounding faults are overlapped by post-extensional deposits of tuff and andesite. Locally, east-west and east-northeast striking andesitic dikes intrude the basin-fill sequences and are consistent with emplacement during north-south extension. In the southern central Walker Lane, half-grabens controlled deposition of rhyolite tuff ranging in age from 28 to 21 Ma and andesite dated at 19 to 15 Ma. Individual faults were variously sealed by 23 Ma rhyolite tuff and mid-Miocene volcanic and sedimentary rocks. In the northern part of the southern Walker Lane, half-grabens localized the deposition of late Oligocene rhyolite tuff dated at 26 Ma and early Miocene andesite, and are sealed by mid-to-Upper Miocene volcanic rocks. Half graben development ceased by the mid-to-late Miocene and the basins were subsequently dissected by Late Miocene to Quaternary faults. Analysis of over 1000 fault-slip measurements collected within late Cenozoic and pre-Cenozoic rocks along major basin-controlling faults indicates the half-grabens formed in a period of regional north-south extension and predated northwest extension associated with Pliocene to contemporary transtensional deformation.

  10. February 2011 sensitive clay landslides at the Çöllolar coalfield, eastern Turkey

    NASA Astrophysics Data System (ADS)

    Akçar, Naki; Yavuz, Vural; Ivy-Ochs, Susan; Nyffenegger, Franziska; Fredin, Ola; Stolz, Martin; Schlunegger, Fritz

    2016-04-01

    The Elbistan basin is an intramontane basin, which is located in the eastern Turkey and bound by the Taurus and Antitaurus Mountains. The basin covers an area of 900 km² at a mean elevation of about 1200 m. The basement rock in this field is karstic limestone, which is overlain by a thick layer of clay (>100 m), followed by 20-50 m thick Lignite series that is overlain by the 20-50 m thick Gyttja sequence. These deposits are overlain by Quaternary deposits, comprising the top surfaces of the terraces of the Hurman River, which drains the surface and ground water from the surrounding hills to the northeast towards the center of the Elbistan basin. The Çöllolar open pit mine, situated in the northwestern sector of the Elbistan basin, contains 90 km2 of mineable coal which has been excavated since 2008. In February 2011, two landslides in which 10 workers were killed, occurred in this field. Of the two landslides, the 2nd and largest which covers an area of ca. 2.3 km2,was caused by the collapse of the northeastern wall of the open-pit mine. The failure was made of successive rearward collapses with the debris flowing into the open-pit. In this study, we focus on the geologic factors that led to instability and the trigger of the landslides. To reveal these factors, we employ sedimentological and geotechnical analysis of deposits, with a special emphasis on the Pliocene lacustrine carbonaceous sediments and the sensitivity of the overlying Quaternary clays. First results from the fieldwork and the mineralogical composition and physical properties of the collected samples indicate that the landslide was caused by the liquefaction of one of the layers within the thick sequence of this part of the Elbistan basin based on the flow style of the movement and nature of the failure. In brief, we conclude that massive failures at the Çöllolar coalfield are unique examples of sensitive clay landslides occurred in a subtropical arid region beyond the extent of Quaternary

  11. A proposed origin for fossilized Pennsylvanian plant cuticles by pyrite oxidation (Sydney Coalfield, Nova Scotia, Canada)

    USGS Publications Warehouse

    Zodrow, E.L.; Mastalerz, Maria

    2009-01-01

    Fossilized cuticles, though rare in the roof rocks of coal seam in the younger part of the Pennsylvanian Sydney Coalfield, Nova Scotia, represent nearly all of the major plant groups. Selected for investigation, by methods of Fourier transform infrared spectroscopy (FTIR) and elemental analysis, are fossilized cuticles (FCs) and cuticles extracted from compressions by Schulze's process (CCs) of Alethopteris ambigua. These investigations are supplemented by FTIR analysis of FCs and CCs of Cordaites principalis, and a cuticle-fossilized medullosalean(?) axis. The purpose of this study is threefold: (1) to try to determine biochemical discriminators between FCs and CCs of the same species using semi-quantitative FTIR techniques; (2) to assess the effects chemical treatments have, particularly Schulze's process, on functional groups; and most importantly (3) to study the primary origin of FCs. Results are equivocal in respect to (1); (2) after Schulze's treatment aliphatic moieties tend to be reduced relative to oxygenated groups, and some aliphatic chains may be shortened; and (3) a primary chemical model is proposed. The model is based on a variety of geological observations, including stratal distribution, clay and pyrite mineralogies associated with FCs and compressions, and regional geological structure. The model presupposes compression-cuticle fossilization under anoxic conditions for late authigenic deposition of sub-micron-sized pyrite on the compressions. Rock joints subsequently provided conduits for oxygen-enriched ground-water circulation to initiate in situ pyritic oxidation that produced sulfuric acid for macerating compressions, with resultant loss of vitrinite, but with preservation of cuticles as FCs. The timing of the process remains undetermined, though it is assumed to be late to post-diagenetic. Although FCs represent a pathway of organic matter transformation (pomd) distinct from other plant-fossilization processes, global applicability of the

  12. Soil quality and carbon sequestration in a reclaimed coal mine spoil of Jharia coalfield, India

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sangeeta; Masto, Reginald; Ram, Lal

    2016-04-01

    Revegetation of coal mine spoil helps in carbon storage and the success of remediation depend on the selection of appropriate tree species. A study was conducted at the coalmine overburden dumps of Jharia Coalfield, Dhanbad, India to evaluate the impact of revegetation on the overall soil quality and carbon sequestration. Morphological parameters (tree height, diameter at breast height, tree biomass, wood specific gravity) of the dominant tree species (Acacia auriculiformis, Cassia siamea, Dalbergia sissoo and Leucaena leucocephala) growing on the mine spoil was recorded. Mine spoil samples were collected under the canopy cover of different tree species and analyzed for soil physical, chemical, and biological parameters. In general reclaimed sites had better soil quality than the reference site. For instance, D. sissoo and C. siamea improved soil pH (+28.5%, +27.9%), EC (+15.65%, +19%), cation exchange capacity (+58.7%, +52.3%), organic carbon (+67.5%, +79.5%), N (+97.2%, +75.7%), P (+98.2%, +76.9%), K (+31.8%, +37.4%), microbial biomass carbon (+143%, +164%) and dehydrogenase activity (+228%, +262%) as compared to the unreclaimed reference coal mine site. The concentration of polycyclic aromatic hydrocarbons (PAHs) decreased significantly in the reclaimed site than the reference spoil, C. siamea was found to be more promising for PAH degradation. The overall impact of tree species on the quality of reclaimed mine spoil cannot be assessed by individual soil parameters, as most of the parameters are interlinked and difficult to interpret. However, combination of soil properties into an integrated soil quality index provides a more meaningful assessment of reclamation potential of tree species. Principal component analysis (PCA) was used to identify key mine soil quality indicators to develop a soil quality index (SQI). Coarse fraction, pH, EC, soil organic carbon, P, Ca, S, and dehydrogenase activity were the most critical properties controlling growth of tree

  13. 5. View from Minnesota bank, near southern side of the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. View from Minnesota bank, near southern side of the southeast portal looking north - Enloe Bridge No. 90021, Spanning Red River of North between Minnesota & North Dakota on County State Aid Highway 28, Wolverton, Wilkin County, MN

  14. Triton Southern Hemisphere

    NASA Image and Video Library

    1998-06-08

    This polar projection from NASA Voyager 2 of Triton southern hemisphere provides a view of the southern polar cap and bright equatorial fringe. The margin of the cap is scalloped and ranges in latitude from +10 degrees to -30 degrees. The bright fringe is closely associated with the cap's margin; from it, diffuse bright rays extend north-northeast for hundreds of kilometers. The bright fringe probably consists of very fresh nitrogen frost or snow, and the rays consist of bright-fringe materials that were redistributed by north-moving Coriolis-deflected winds. http://photojournal.jpl.nasa.gov/catalog/PIA00423

  15. Triton's Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This polar projection of Triton's southern hemisphere provides a view of the southern polar cap and bright equatorial fringe. The margin of the cap is scalloped and ranges in latitude from +10 degrees to -30 degrees. The bright fringe is closely associated with the cap's margin; from it, diffuse bright rays extend north-northeast for hundreds of kilometers. The bright fringe probably consists of very fresh nitrogen frost or snow, and the rays consist of bright-fringe materials that were redistributed by north-moving Coriolis-deflected winds.

  16. Dusty Skies over Southern California

    NASA Image and Video Library

    2002-02-20

    Southern California Santa Anas are dry, north-easterly winds having speeds in excess of 25 knots 46 kilometers/hour. Santa Ana conditions are commonly associated with gusts of more than twice this level.

  17. Late Pleistocene evolution of the Rhine-Meuse system in the southern North Sea basin: imprints of climate change, sea-level oscillation and glacio-isostacy

    NASA Astrophysics Data System (ADS)

    Busschers, F. S.; Kasse, C.; van Balen, R. T.; Vandenberghe, J.; Cohen, K. M.; Weerts, H. J. T.; Wallinga, J.; Johns, C.; Cleveringa, P.; Bunnik, F. P. M.

    2007-12-01

    High-resolution continuous core material, geophysical measurements, and hundreds of archived core descriptions enabled to identify 13 Late Pleistocene Rhine-Meuse sedimentary units in the infill of the southern part of the North Sea basin (the Netherlands, northwestern Europe). This sediment record and a large set of Optical Stimulated Luminescence dates, 14C dates and biostratigraphical data, allowed to establish detailed relationships between climate change, sea-level oscillation, glaciation history and the sedimentary development of the Rhine fluvial system during the last glacial cycle (Marine Isotope Stages 5e-2, Eemian-Weichselian). A well-preserved Eemian sediment record was encountered as the infill of a Late Saalian (MIS6) subglacial basin. Part of this record reflects groundwater rise controlled (fine-grained) sedimentation as a result of postglacial (early) Eemian sea-level rise. It shows strong analogy to developments known from the Holocene Rhine-Meuse delta. Outside of the glacial depressions near coastal deposits are only fragmentarily preserved. The Early Glacial Rhine sediment record is dominated by organic debris and peat layers, marking landscape stability and low fluvial activity. Part of this record may have been formed under near coastal conditions. Significant amounts of reworked marine biomarkers in the lag-deposits of Early Pleniglacial (MIS4) fluvial systems indicate that this period is characterized by extensive reworking of older (MIS5) near-coastal sediments. Despite the marked Early Pleniglacial climatic cooling, input of new sediment from the drainage basin was relatively low, a feature that is related to the presence of regolith protective relic soil complexes in the basin. During the early Middle Pleniglacial, a major Rhine avulsion indicates the system was in an aggrading mode and that sediment supply into the lower reaches of the Rhine had strongly increased. This increase in sediment supply coincided with the timing of major

  18. Effects of faults as barriers or conduits to displaced brine flow on a putative CO2 storage site in the Southern North Sea

    NASA Astrophysics Data System (ADS)

    Hannis, Sarah; Bricker, Stephanie; Williams, John

    2013-04-01

    The Bunter Sandstone Formation in the Southern North Sea is a potential reservoir being considered for carbon dioxide storage as a climate change mitigation option. A geological model of a putative storage site within this saline aquifer was built from 3D seismic and well data to investigate potential reservoir pressure changes and their effects on fault movement, brine and CO2 migration as a result of CO2 injection. The model is located directly beneath the Dogger Bank Special Area of Conservation, close to the UK-Netherlands median line. Analysis of the seismic data reveals two large fault zones, one in each of the UK and Netherlands sectors, many tens of kilometres in length, extending from reservoir level to the sea bed. Although it has been shown that similar faults compartmentalise gas fields elsewhere in the Netherlands sector, significant uncertainty remains surrounding the properties of the faults in our model area; in particular their cross- and along-fault permeability and geomechanical behaviour. Despite lying outside the anticipated CO2 plume, these faults could provide potential barriers to pore fluid migration and pressure dissipation, until, under elevated pressures, they provide vertical migration pathways for brine. In this case, the faults will act to enhance injectivity, but potential environmental impacts, should the displaced brine be expelled at the sea bed, will require consideration. Pressure gradients deduced from regional leak-off test data have been input into a simple geomechanical model to estimate the threshold pressure gradient at which faults cutting the Mesozoic succession will fail, assuming reactivation of fault segments will cause an increase in vertical permeability. Various 4D scenarios were run using a single-phase groundwater modelling code, calibrated to results from a multi-phase commercial simulator. Possible end-member ranges of fault parameters were input to investigate the pressure change with time and quantify brine

  19. Map showing general chemical quality of ground water in the Alton-Kolob coal-fields area, Utah

    USGS Publications Warehouse

    Price, Don

    1981-01-01

    This is one of a series of maps that describes the geology and related natural resources of the Alton-Kolob coal-fields area, Utah. The purpose of this map is to show regional variations in ground-water quality as depicted by its dissolved-solids concentration. The map is based on chemical analyses of water samples from springs, streams during base flow, and wells less than 1.000 feet deep. There are significant areal and vertical variations in the ground-water quality – especially in those areas where the dissolved-solids concentrations range from 100 to 1,000 and from 500 to 3,000 mg/L (milligrams per liter). Consequently, determination of the actual chemical quality of the ground-water, including concentrations of specific ions in any given locality, can be made only by special investigation.

  20. Prevalence of antibodies to Trypanosoma cruzi, Toxoplasma gondii, Encephalitozonn cuniculi, Sarcocystis neurona, Besnoitia darlingi, and Neospora caninum in North American opossum, Didelphis virginiana, from Southern Louisian

    USDA-ARS?s Scientific Manuscript database

    We examined the prevalence of antibodies to zoonotic protozoan parasites (Trypanosoma cruzi, Toxoplasma gondii, and Encephalitozoon cuniculi) and protozoan’s of veterinary importance (Neospora caninum, Sarcocystis neurona and Besnoitia darlingi) in a population of North American opossums (Didelphis...

  1. Effects of microhabitat and large-scale land use on stream salamander occupancy in the coalfields of Central Appalachia

    USGS Publications Warehouse

    Sweeten, Sara E.; Ford, W. Mark

    2016-01-01

    Large-scale coal mining practices, particularly surface coal extraction and associated valley fills as well as residential wastewater discharge, are of ecological concern for aquatic systems in central Appalachia. Identifying and quantifying alterations to ecosystems along a gradient of spatial scales is a necessary first-step to aid in mitigation of negative consequences to aquatic biota. In central Appalachian headwater streams, apart from fish, salamanders are the most abundant vertebrate predator that provide a significant intermediate trophic role linking aquatic and terrestrial food webs. Stream salamander species are considered to be sensitive to aquatic stressors and environmental alterations, as past research has shown linkages among microhabitat parameters, large-scale land use such as urbanization and logging, and salamander abundances. However, there is little information examining these relationships between environmental conditions and salamander occupancy in the coalfields of central Appalachia. In the summer of 2013, 70 sites (sampled two to three times each) in the southwest Virginia coalfields were visited to collect salamanders and quantify stream and riparian microhabitat parameters. Using an information-theoretic framework, effects of microhabitat and large-scale land use on stream salamander occupancy were compared. The findings indicate that Desmognathus spp. occupancy rates are more correlated to microhabitat parameters such as canopy cover than to large-scale land uses. However, Eurycea spp. occupancy rates had a strong association with large-scale land uses, particularly recent mining and forest cover within the watershed. These findings suggest that protection of riparian habitats is an important consideration for maintaining aquatic systems in central Appalachia. If this is not possible, restoration riparian areas should follow guidelines using quick-growing tree species that are native to Appalachian riparian areas. These types of trees

  2. Effects of magmatic intrusion on mineralogy and geochemistry of coals from the Fengfeng-Handan Coalfield, Hebei, China

    SciTech Connect

    Shifeng Dai; Deyi Ren

    2007-06-15

    This paper describes the effects of magmatic intrusions on petrology, mineralogy, and geochemistry of the late Palaeozoic coals from the Fengfeng-Handan coalfield, Hebei, China. The narrowly zoned coals of variable ranks, from high-volatile A bituminous (hvAb), through medium-volatile bituminous (mvb), low-volatile bituminous (lvb), semianthracite (sa), and anthracite (an), to meta-anthracite (ma) in the coalfield, were found to be best explained by magmatic inputs. The minerals derived from magmatic thermal alteration consist of pyrite, calcite, and ankerite, which mainly occur as fracture or vesicle fillings in the thermally altered high-rank coals. The variation in element concentrations with coal ranks (enrichment, depletion, and no variation) and mineralogical affinity were used to classify elements in coals into six groups, groups A-F. Elements in group A (B, F, Cl, Br, and Hg), group B (As, Co, Cu, Ni, and Pb), group C (Sr, Mg, Ca, Mn, and Zn), and Group D (U) were enriched in the altered coals, indicating that the magmatic inputs are the source of these elements. Group A elements are volatile elements that probably came from the hydrothermal solutions, then deposited or were driven off from an organic component in coal by magmatic heat, and then redeposited in the coal. Group B elements mainly distribute in the fracture or vesicle fillings of pyrites. The dominant carriers of group C elements are thermally altered calcite and ankerite. Uranium in group D occurs in organic-bonded and silicate associations. Group E elements, including Sb, Sc, and V, have a depletion trend in the altered coals, and the remaining elements in group F do not clearly vary in the unaltered, slightly altered, or altered coals. The element concentrations independent of coal ranks in groups E and F may suggest that these elements are inherent to the coal. 44 refs., 15 figs., 5 tabs.

  3. Validation of a stream and riparian habitat assessment protocol using stream salamanders in the southwest Virginia coalfields

    USGS Publications Warehouse

    Sweeten, Sara E.; Ford, W. Mark

    2016-01-01

    Within the central Appalachia Coalfields, the aquatic impacts of large-scale land uses, such as surface mining, are of particular ecological concern. Identification and quantification of land use impacts to aquatic ecosystems are a necessary first step to aid in mitigation of negative consequences to biota. However, quantifying physical environmental quality such as stream and riparian habitat often can be quite difficult, particularly when there is time or fiscal limitations. As such, standard protocols such as the U.S. EPA’s Stream Habitat Rapid Bioassessment Protocol have been established to be cost- and time-effective. This protocol estimates ten different stream and riparian conditions on a scale of 0 to 20. Unfortunately, using estimations can be problematic because of large potential variation in the scoring depending on differences in training, experience, and opinion of the personnel doing the estimations. In order to help negate these biases and provide a simplified process, the U.S. Army Corps of Engineers (USACE) developed a functional assessment for streams that measures 11 stream and riparian variables along with watershed land use to calculate three different scores, a hydrology score, biogeochemical score, and habitat score. In our study, we examined the correlation of stream salamander presence and abundance to the three USACE scores. In the summer of 2013, we visited 70 sites in the southwest Virginia Coalfields multiple times to collect salamanders and quantify stream and riparian microhabitat parameters. Using occupancy and abundance analyses, we found strong relationships among three Desmognathus spp. and the USACE Habitat FCI score. Accordingly, the Habitat FCI score provides a reasonable assessment of physical instream and riparian conditions that may serve as a surrogate for understanding the community composition and integrity of aquatic salamander in the region.

  4. Effects of Watershed Land Use and Geomorphology on Stream Low Flows During Severe Drought Conditions in the Southern Blue Ridge Mountains, Georgia and North Carolina, United States

    EPA Science Inventory

    Land use and physiographic variability influence stream low flows, yet their interactions and relative influence remain unresolved. Our objective was to assess the influence of land use and watershed geomorphic characteristics on low-flow variability in the southern Blue Ridge Mo...

  5. Effects of Watershed Land Use and Geomorphology on Stream Low Flows During Severe Drought Conditions in the Southern Blue Ridge Mountains, Georgia and North Carolina, United States

    EPA Science Inventory

    Land use and physiographic variability influence stream low flows, yet their interactions and relative influence remain unresolved. Our objective was to assess the influence of land use and watershed geomorphic characteristics on low-flow variability in the southern Blue Ridge Mo...

  6. Modeling the long-term effects of oak shelterwood regeneration treatments on species diversity and oak abundance in southern Appalachian forests of North Carolina

    Treesearch

    Tara L. Keyser; Chad E. Keyser

    2013-01-01

    In April 2008, the Upland Hardwoods Ecology and Management Research Work Unit of the U.S. Forest Service, Southern Research Station began a long-term cooperative study to describe forest ecosystem response to three oak (Quercus spp.) shelterwood regeneration treatments in the central hardwoods region of the United States. Pretreatment inventory data...

  7. Cuticular hydrocarbons and soldier defense secretions of Reticulitermes in southern California: a critical analysis of the taxonomy of the genus in North America

    Treesearch

    Lori J. Nelson; Laurence G. Cool; Christopher W. Solek; Michael I. Haverty

    2008-01-01

    Cuticular hydrocarbons (CHC) and soldier defense secretions (SDS) were characterized for collections of Reticulitermes from six counties (Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Santa Barbara) in southern California. Collection sites included the type locality for R. hesperus, Lake Arrowhead (formerly known as Little Bear Lake) in the San...

  8. Frequency and magnitude of selected historical landslide events in the southern Appalachian Highlands of North Carolina and Virginia: relationships to rainfall, geological and ecohydrological controls, and effects

    Treesearch

    Richard M. Wooten; Anne C. Witt; Chelcy F. Miniat; Tristram C. Hales; Jennifer L. Aldred

    2016-01-01

    Landsliding is a recurring process in the southern Appalachian Highlands (SAH) region of the Central Hardwood Region. Debris flows, dominant among landslide processes in the SAH, are triggered when rainfall increases pore-water pressures in steep, soil-mantled slopes. Storms that trigger hundreds of debris flows occur about every 9 years and those that...

  9. Cuticular hydrocarbons and soldier defense secretions of Reticulitermes in southern California: a critical analysis of the taxonomy of the genus in North America.

    PubMed

    Nelson, Lori J; Cool, Laurence G; Solek, Christopher W; Haverty, Michael I

    2008-11-01

    Cuticular hydrocarbons (CHC) and soldier defense secretions (SDS) were characterized for collections of Reticulitermes from six counties (Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Santa Barbara) in southern California. Collection sites included the type locality for R. hesperus, Lake Arrowhead (formerly known as Little Bear Lake) in the San Bernardino Mountains. In southern California, there are two CHC phenotypes, SC-A and SC-B, which are easily distinguished by the presence or absence of 5-methyl pentacosane, 5-methyl heptacosane, 5,17-dimethyl pentacosane, and 5,17-dimethyl heptacosane. These phenotypes are similar, but not identical, to previously designated phenotypes of Reticulitermes from northern California. The SDS of termites collected from southern California were characterized; (-)-germacrene A was abundant in all but the four samples from Lake Arrowhead. Soldiers of phenotype SC-A produced >79% germacrene A. The four samples from Lake Arrowhead produced no germacrene A, but contained >78% gamma-cadinene. The SDS from the Lake Arrowhead samples were more similar to those of CA-A/CA-A' from northern California than to any of the CHC phenotypes from southern California. Soldiers of CHC phenotype SC-B produced germacrene A, with the proportion varying from 16.2 to 98.7%. The SDS of SC-B were more similar to those of SC-A than to any of the phenotypes from northern California. The CHC phenotype SC-A found in southern California likely represents R. hesperus and SC-B appears to be a new, as yet undescribed species. We discuss the state of current taxonomic research on Reticulitermes.

  10. Preliminary JIRAM results from Juno polar observations: 2. Analysis of the Jupiter southern H3+ emissions and comparison with the north aurora

    NASA Astrophysics Data System (ADS)

    Adriani, A.; Mura, A.; Moriconi, M. L.; Dinelli, B. M.; Fabiano, F.; Altieri, F.; Sindoni, G.; Bolton, S. J.; Connerney, J. E. P.; Atreya, S. K.; Bagenal, F.; Gérard, J.-C. M. C.; Filacchione, G.; Tosi, F.; Migliorini, A.; Grassi, D.; Piccioni, G.; Noschese, R.; Cicchetti, A.; Gladstone, G. R.; Hansen, C.; Kurth, W. S.; Levin, S. M.; Mauk, B. H.; McComas, D. J.; Olivieri, A.; Turrini, D.; Stefani, S.; Amoroso, M.

    2017-05-01

    The Jupiter InfraRed Auroral Mapper (JIRAM) aboard Juno observed the Jovian South Pole aurora during the first orbit of the mission. H3+ (trihydrogen cation) and CH4 (methane) emissions have been identified and measured. The observations have been carried out in nadir and slant viewing both by a L-filtered imager and a 2-5 μm spectrometer. Results from the spectral analysis of the all observations taken over the South Pole by the instrument are reported. The coverage of the southern aurora during these measurements has been partial, but sufficient to determine different regions of temperature and abundance of the H3+ ion from its emission lines in the 3-4 μm wavelength range. Finally, the results from the southern aurora are also compared with those from the northern ones from the data taken during the same perijove pass and reported by Dinelli et al. (2017).

  11. Genetic separation of southern and northern soybean breeding programs in North America and their associated allelic variation at four maturity loci

    USDA-ARS?s Scientific Manuscript database

    Soybean has only 90 years of breeding history in North America. During the short breeding period, soybean breeders have successfully developed a large collection of elite cultivars with diverse maturity groups. To understand the molecular and genetic basis underlying the diverse soybean maturity, ...

  12. Urban and community forests of the Southern Atlantic region: Delaware, District of Columbia, Florida, Georgia, Maryland, North Carolina, South Carolina, Virginia, West Virginia

    Treesearch

    David J. Nowak; Eric J. Greenfield

    2009-01-01

    This report details how land cover and urbanization vary within the states of Delaware, Florida, Georgia, Maryland, North Carolina, South Carolina, Virginia, and West Virginia; and the District of Columbia by community (incorporated and census designated places), county subdivision, and county. Specifically this report provides critical urban and community forestry...

  13. Seismicity of the Wrangell and Aleutian Wadati-Benioff Zones and the North American Plate along the Trans-Alaska Crustal Transect, Chugach Mountains and Copper River Basin, southern Alaska

    NASA Astrophysics Data System (ADS)

    Page, Robert A.; Stephens, Christopher D.; Lahr, John C.

    1989-11-01

    The configuration of the Aleutian and Wrangell Wadati-Benioff zones in southern Alaska between longitudes 142°W and 148°W is determined from regionally recorded earthquakes from 1971 to 1986. The earthquakes are located with a simple velocity model calibrated with seismic refraction measurements conducted for the Trans-Alaska Crustal Transect (TACT). West of the transect meridian (approximately 145°20'W) and beneath the Chugach Mountains, shocks in the depth range 25-60 km compose the shallow part of the northwest to north dipping Aleutian zone. This zone can be traced updip and seaward beneath Prince William Sound. East of the transect meridian and north of 61°N latitude, the weakly active, north-northeast dipping Wrangell zone extends to a depth of at least 100 km beneath the Wrangell volcanoes and along strike for at least 150 km. The two zones appear to be continuous, at least in the depth range 20-45 km, and may define adjacent limbs of a buckle in the subducted oceanic lithosphere. North of 61°N, focal mechanisms in the shallow Aleutian zone are compatible with a uniform stress field characterized by in-plane least compressive stress directed toward the steeply dipping, deeper part of the Aleutian zone north of Cook Inlet. Stress orientation in the Wrangell zone is unresolved because of the low level of seismicity. No focal mechanisms corresponding to slip on a gently northward dipping megathrust have been observed. Along the transect meridian, a change of focal mechanism with depth near the top of the dipping seismic zone is inferred to reflect the interplate boundary beneath the Chugach Mountains. This boundary coincides with a band of strong reflectors imaged by TACT vertical seismic profiling. The overriding plate appears to be aseismic beneath the northern Chugach Mountains, but minor shallow seismicity occurs beneath the Copper River Basin. First-motion patterns for these shallow shocks suggest the most compressive stress within the overriding

  14. Long-term monitoring study of beached seabirds shows that chronic oil pollution in the southern North Sea has almost halted.

    PubMed

    Stienen, Eric W M; Courtens, Wouter; Van de Walle, Marc; Vanermen, Nicolas; Verstraete, Hilbran

    2017-02-15

    Trends in oil rates of beached seabirds reflect temporal and spatial patterns in chronic oil pollution at sea. We analysed a long-term dataset of systematic beached bird surveys along the Belgian North Sea coast during 1962-2015, where extreme high oil contamination rates and consequently high mortality rates of seabirds during the 1960s used to coincide with intensive ship traffic. In the 1960s, >90% of all swimming seabirds that washed ashore were contaminated with oil and estimated oil-induced mortality of seabirds was probably several times higher than natural mortality. More than 50years later oil rates of seabirds have dropped to historically low levels while shipping is still very intense, indicating that chronic oil pollution has significantly declined. The declining trend is discussed in the light of a series of legislative measures that were enacted in the North Sea region to reduce oil pollution.

  15. The Variability of the Atlantic Meridional Overturning Circulation, the North Atlantic Oscillation, and the El Niño-Southern Oscillation in the Bergen Climate Model.

    NASA Astrophysics Data System (ADS)

    Mignot, Juliette; Frankignoul, Claude

    2005-07-01

    The link between the interannual to interdecadal variability of the Atlantic meridional overturning circulation (AMOC) and the atmospheric forcing is investigated using 200 yr of a control simulation of the Bergen Climate Model, where the mean circulation cell is rather realistic, as is also the location of deep convection in the northern North Atlantic. The AMOC variability has a slightly red frequency spectrum and is primarily forced by the atmosphere. The maximum value of the AMOC is mostly sensitive to the deep convection in the Irminger Sea, which it lags by about 5 yr. The latter is mostly forced by a succession of atmospheric patterns that induce anomalous northerly winds over the area. The impact of the North Atlantic Oscillation on deep convection in the Labrador and Greenland Seas is represented realistically, but its influence on the AMOC is limited to the interannual time scale and is primarily associated with wind forcing. The tropical Pacific shows a strong variability in the model, with too strong an influence on the North Atlantic. However, its influence on the tropical Atlantic is realistic. Based on lagged correlations and the release of fictitious Lagrangian drifters, the tropical Pacific seems to influence the AMOC with a time lag of about 40 yr. The mechanism is as follows: El Niño events induce positive sea surface salinity anomalies in the tropical Atlantic that are advected northward, circulate in the subtropical gyre, and then subduct. In the ocean interior, part of the salinity anomaly is advected along the North Atlantic current, eventually reaching the Irminger and Labrador Seas after about 35 yr where they destabilize the water column and favor deep convection.

  16. Hydrogeology and sources of recharge to the Buffalo and Wahpeton aquifers in the southern part of the Red River of the North drainage basin, west-central Minnesota and southeastern North Dakota

    USGS Publications Warehouse

    Schoenberg, Michael

    1998-01-01

    The potential sources of recharge to the Wahpeton aquifers investigated were the Red River of the North, and adjacent hydro geologic units. The volume of ground water pumped from the Wahpeton aquifers provides an estimate of the upper limit for the volume of recharge to the aquifer. Based on pumpage from all of the Wapheton aquifers from 1990 to 1993, the upper limit is about 580 million gallons per year (2.4 x 105 cubic feet per day).

  17. Tertiary tectonics of the sub-Andean region of the North Patagonian Andes, southern central Andes of Argentina (41 42°30‧S)

    NASA Astrophysics Data System (ADS)

    Giacosa, Raúl E.; Afonso, Juan C.; Heredia C., Nemesio; Paredes, José

    2005-12-01

    The sub-Andean region of the North Patagonian Andes is located between the north Patagonian foreland and the highest elevations of the Andean Cordillera. Its Tertiary contractional structure, active since the upper Late Oligocene and through the upper Late Miocene, corresponds to the external sector of the North Patagonian Andes fold-and-thrust belt, which is characterized by east-vergent thrusts that affect stratified Cenozoic rocks. The units involved in the deformation correspond to El Maitén Oligocene volcanic belt, deformed between east-vergent thrusts and backthrusts, and Oligocene-Miocene sedimentary rocks of the Ñirihuau-Collón Curá Basin. The northern sector of the basin was structured as a thin-skinned fold belt that comprises the Ñirihuau fold belt and a frontal sedimentary wedge. To the south, sedimentary depocenters are confined between medium- to high-angle reverse faults with evidence of basement structural control. In both cases, the general tectonosedimentary framework shows the youngest units toward the east, in agreement with the advance of the orogenic wedge. Most of the Ñirihuau-Collón Curá Basin infill fits a foreland basin system model. Some sectors of the basin show evidence of structural control by normal faults in the initial sedimentation stages. This early extensional regime might be associated with late phases of Oligocene volcanism. Extensional structures probably were partially reactivated during the upper Late Oligocene, as suggested by seismic data.

  18. Late Pleistocene Magnitude Glacial Incursions of Southern Component Water to the Deep North Atlantic Resolved Using Nd Isotopes during the Intensification of Northern Hemisphere Glaciation (3.3 to 2.4 Ma)

    NASA Astrophysics Data System (ADS)

    Lang, D.; Bailey, I.; Wilson, P. A.; Foster, G. L.; Gutjahr, M.

    2014-12-01

    The ocean, through its ability to globally redistribute heat and partition carbon dioxide, is believed to play a key role in driving and amplifying climate change during Quaternary glaciations on orbital to millennial timescales. Relatively little is known, however, about changes in Atlantic Meridional Overturning Circulation (AMOC) associated with the Pliocene intensification of Northern Hemisphere glaciation (iNHG). To help fill this gap in our knowledge we present a new high resolution (~6 ka) record of the Nd isotope composition of the deep North Atlantic between ~3.3 and 2.4 Ma, measured on fish debris at IODP Site U1313 (3426 m, 41°N, 32.5°W). This record represents the first orbital-resolution record of variations in watermass mixing in this region for iNHG independent of changes in the carbon cycle and, in contrast to existing benthic foraminiferal δ13C records for this time interval, our Nd dataset contains evidence for late Pleistocene magnitude incursions of Southern Component Waters to the deep North Atlantic Ocean during key glacial periods through this time. We therefore infer an important role for AMOC variability in amplifying Quaternary glacial-interglacial cycles

  19. Depositional controls on coal distribution and quality in the Eocene Brunner Coal Measures, Buller Coalfield, South Island, New Zealand

    USGS Publications Warehouse

    Flores, R.M.; Sykes, R.

    1996-01-01

    The Buller Coalfield on the West Coast of the South Island, New Zealand, contains the Eocene Brunner Coal Measures. The coal measures unconformably overlie Paleozoic-Cretaceous basement rocks and are conformably overlain by, and laterally interfinger with, the Eocene marine Kaiata Formation. This study examines the lithofacies frameworks of the coal measures in order to interpret their depositional environments. The lower part of the coal measures is dominated by conglomeratic lithofacies that rest on a basal erosional surface and thicken in paleovalleys incised into an undulating peneplain surface. These lithofacies are overlain by sandstone, mudstone and organic-rich lithofacies of the upper part of the coal measures. The main coal seam of the organic-rich lithofacies is thick (10-20 m), extensive, locally split, and locally absent. This seam and associated coal seams in the Buller Coalfield are of low- to high-volatile bituminous rank (vitrinite reflectance between 0.65% and 1.75%). The main seam contains a variable percentage of ash and sulphur. These values are related to the thickening and areal distribution of the seam, which in turn, were controlled by the nature of clastic deposition and peat-forming mire systems, marine transgression and local tidal incursion. The conglomeratic lithofacies represent deposits of trunk and tributary braided streams that rapidly aggraded incised paleovalleys during sea-level stillstands. The main seam represents a deposit of raised mires that initially developed as topogenous mires on abandoned margins of inactive braidbelts. Peat accumulated in mires as a response to a rise in the water table, probably initially due to gradual sea-level rise and climate, and the resulting raised topography served as protection from floods. The upper part of the coal measures consists of sandstone lithofacies of flu vial origin and bioturbated sandstone, mudstone and organic-rich lithofacies, which represent deposits of paralic (deltaic

  20. Lesser black-backed gulls (Larus fuscus) consuming swimming crabs: An important link in the food web of the southern North Sea

    NASA Astrophysics Data System (ADS)

    Schwemmer, Henriette; Schwemmer, Philipp; Ehrich, Siegfried; Garthe, Stefan

    2013-03-01

    Swimming crabs (Liocarcinus spp.) are one of the most common brachyuran species in the North Sea, and their abundance has substantially increased over the last century. Seabirds such as lesser black-backed gulls (LBBG) commonly feed mainly on higher-trophic-level organisms such as fish. However, intensive use of swimming crabs by LBBGs in the eastern North Sea has been noted over several years. Our investigation of this aspect of the food web by examining food remains from breeding LBBGs showed that swimming crabs accounted for more than half of the nutrition of LBBGs. Gulls selected larger individuals than expected, based on sizes of free-living swimming crabs. A long-term data set (2002-2006) shows that gulls took swimming crabs mainly in the early morning and late evening, suggesting that they might migrate vertically in the water column. Moreover, it shows that although swimming crabs occurred at considerable distances from the shore, LBBGs took this prey item exclusively from near the shore where it was most abundant. This suggests the existence of a possible energy threshold above which gulls experience a net energy loss, if they have to travel too far from their colony, where the abundance of swimming crabs is lower and the energy intake might thus not compensate for the long-distance flights. Swimming-crab abundance did not appear to be the primary factor influencing overall gull distribution. A simple bioenergetic model showed that the 22,000 individual LBBGs in the most important breeding colony in the south-eastern North Sea consumed approximately 35 million swimming crabs annually (i.e. 1590 swimming crabs per individual gull) during the breeding period. However, considering the high numbers of swimming crabs in the south-eastern North Sea (demonstrated by bottom-trawl surveys in 2005 and 2007) LBBGs are unlikely to exert top-down control on this prey. Conversely, a bottom-up effect is more likely, potentially enabling further increases in LBBG

  1. The winter distribution of nutrients in the Southern Bight of the North Sea (1961-1978) and in the estuaries of the scheldt and the rhine/meuse

    NASA Astrophysics Data System (ADS)

    van Bennekom, A. J.; Wetsteijn, F. J.

    In many years the winter distribution of nutrients in the eastern part of the Southern Bight is influenced by phytoplankton growth, always in February, sometimes in January but not in January 1961 and 1978, months with a relatively low insolation and high wind strength. The Scheldt river has higher nutrient concentrations than the rivers Rhine and Seine. The waters of the Scheldt river plume are distinguished from those of the Seine and the Rhine/Meuse with dissolved silica as a tracer. The extension of the Scheldt river plume is related to wind direction. The increase of inorganic nutrients from January 1961 to January 1978 in the northern part of the Southern Bight is related to the increase in the river Rhine. The increase in the Strait of Dover is related to discharges from the river Seine and the English coast. Only data outside the Scheldt river plume were selected for the comparison. An increase of nutrient concentrations is measurable over the entire salinity range and is largest for phosphate (up to 3 times at low salinities), less for nitrate (about 1.5 times for all salinities) and hardly noticeable for silicic acid. Nitrate extrapolation to low salinity agrees with upstream river values, but phosphate extrapolation gives higher concentrations, probably due to discharges of phosphogypsum in estuaries.

  2. Pleistocene volcaniclastic units from North-Eastern Sicily (Italy): new evidence for calc-alkaline explosive volcanism in the Southern Tyrrhenian Sea

    NASA Astrophysics Data System (ADS)

    Di Bella, Marcella; Italiano, Francesco; Sabatino, Giuseppe; Tripodo, Alessandro; Baldanza, Angela; Casella, Sergio; Pino, Paolo; Rasa', Riccardo; Russo, Selma

    2016-08-01

    A well-preserved volcaniclastic sequence crops out in Pleistocene marine sediments along the Tyrrhenian coastline of the Calabrian-Peloritani arc (Sicily, Italy), testifying the occurrence of Lower-Middle Pleistocene volcanic activity in Southern Tyrrhenian Sea. The presence of dominant highly vesicular and minor blocky glassy particles indicates that the volcanic clasts were originated by explosive events related to the ascent and violent emission of volatile-rich magmas accompanied by and/or alternated with hydromagmatic fragmentation due to magma-sea water interaction. Field investigations and sedimentological features of the studied volcaniclastic units suggest a deposition from sediment-water density flows. The chemical classification of the pumice clasts indicates prevalent rhyolitic and dacitic compositions with calc-alkaline to high-K calc-alkaline affinity. The geochemical features of immobile trace elements together with the presence of orthopyroxene are indicative of a provenance from an arc-type environment. The age (from 980-910 to 589 ka), the chemical composition and the evidence of subaerial explosive volcanic activity constrain the origin nature and temporal evolution of the arc-type volcanism in the Southern Tyrrhenian domain. Finally, the new information here provided contribute to a better understanding of the temporal geodynamic evolution of this sector of the Mediterranean domain.

  3. Southern phosphorus indices, water quality data, and modeling (APEX, APLE, and TBET) results: A comparison

    USDA-ARS?s Scientific Manuscript database

    Phosphorus (P) indices in the southern United States frequently produce different recommendations for similar conditions. After assembling data from benchmark southern sites (Arkansas, Georgia, Mississippi, North Carolina, Oklahoma, and Texas), land treatment information was used in the 12 southern...

  4. 6. Interior oblique view from doorway, Oil House, Southern Pacific ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Interior oblique view from doorway, Oil House, Southern Pacific Railroad Carlin Shops, view to north (90mm lens). - Southern Pacific Railroad, Carlin Shops, Oil House, Foot of Sixth Street, Carlin, Elko County, NV

  5. 14. Interior, Machine Shop, Roundhouse Machine Shop Extension, Southern Pacific ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Interior, Machine Shop, Roundhouse Machine Shop Extension, Southern Pacific Railroad Carlin Shops, view to north (90mm lens). - Southern Pacific Railroad, Carlin Shops, Roundhouse Machine Shop Extension, Foot of Sixth Street, Carlin, Elko County, NV

  6. Guiana's Basin, A Unique Setting with Two Break-up and Drift Unconformities and a Feature Hypothesized to be a Southern North Atlantic, Iceland Equivalent Atlantis

    NASA Astrophysics Data System (ADS)

    Kean, A. E.

    2007-12-01

    In the Guiana's Basin, two distinct Break-up/Drift Unconformities associated with thermal doming, rifting, cooling, compressing and drifting of plates were identified and mapped. The earliest unconformity 1) Mid-Jurassic-aged separation of North/Central America from Western Europe/North Western Africa and the latest unconformity 2) Albian-aged separation of Central West Africa from Central Northern South America, exist here. What complicates the interpretation of the plate motion is the amount of overburden deposited post Albian time on both sides of the ridge separating the African and the South American plates. To the east, the Niger River pushed out 5-20 km of sediments on top of the drift unconformity. In the Guiana's Basin the sedimentation is only about 5-10 km of sedimentation therefore it is easier to image and interpret the geologic history. Through a synthetic well to seismic tie, a correlation of new biostratigraphic data from a well spud in Nov. 1977 and TD'ed in June of 1978 by Esso, was incorporated into the regional geologic interpretation. The interpretation based on this data was that the timing of the opening of the South Atlantic was synchronous with that of the North Atlantic. The feature of interest closely resembles a buried volcanic landmass. It just happens to be located in the area hypothesized as the Mid Jurassic spreading center related to a hotspot, after Pindell and Kendall, March 2005. Interpretation and conclusions for this study are based on 1999 and 2004 vintages of 2D seismic data and a new interpretation of the biostratigraphy. Additionally, gravity and magnetic data along with regional subsidence modeling and a tectonic evaluation study supports these conclusions. On several 2D seismic lines from the area, a deep volcanic feature can be seen and interpreted to exist in Mid Jurassic time. This feature is similar in portion to Iceland the volcanic island currently residing in the middle of the North Atlantic Ocean. Today in the

  7. Sequential solvent extraction for the modes of occurrence of selenium in coals of different ranks from the Huaibei Coalfield, China

    PubMed Central

    Zhang, Ying; Liu, Guijian; Chou, Chen-Lin; Wang, Lei; Kang, Yu

    2007-01-01

    Forms of selenium in bituminous coal, anthracite, and cokeite (natural coke) from Huaibei Coalfield, Anhui, China, have been determined by sequential solvent extraction. The selenium content in bulk samples is 4.0, 2.4, and 2.0 μg/g in bituminous coal, anthracite, and cokeite, respectively. The six forms of selenium determined by six-step solvent extraction are water-leachable, ion-exchangeable, organic matter-associated, carbonate-associated, silicate-associated, and sulfide-associated. The predominant forms of selenium in bituminous coal are organic matter-associated (39.0%), sulfide-associated (21.1%), and silicate bound (31.8%); these three forms account for 92% of the total. The organic matter bound-selenium decrease dramatically from bituminous coal (39.0%) to anthracite (11.6%) and to cokeite (0%), indicating that organic matter bound selenium is converted to other forms during metamorphism of the coal, most likely sulfide-form. The sulfide-associated form increased remarkably from bituminous coal (21.1%) to anthracite (50.4%) and cokeite (54.5%), indicating the formation of selenium sulfide, possibly in pyrite during the transformation of bituminous coal to anthracite and cokeite. The silicate-associated selenium in bituminous coal (31.8%) is much higher than that in anthracite (16.4%) and cokeite (15.8%), indicating that silicate-associated selenium is partly converted to sulfide during metamorphism. PMID:18093341

  8. Controls on boron and germanium distribution in the low-sulfur Amos coal bed, Western Kentucky coalfield, USA

    USGS Publications Warehouse

    Hower, J.C.; Ruppert, L.F.; Williams, D.A.

    2002-01-01

    The Duckmantian-aged Amos coal bed is a thin (<51 cm) coal bed that occurs in lobate southwest-trending pods separated by thin sandstones in the Western Kentucky coalfield. The coal bed, which is comprised of up to two benches and a rider coal, is low in ash yield (<6%) and sulfur content (<1%). The coal tends to be thin (<40 cm), but it was heavily mined in the 1980s because it could be combusted as mined. Geochemical analysis of the Amos coal bed shows higher concentrations of B and Ge than other Western Kentucky coal beds. High total B concentrations as well as high B/Be, both considered to be indicators of marine environments, increase toward the top of the coal bed. Most of the B values for the Amos samples range from 66 to 103 ppm (whole coal basis) indicating deposition in a brackish environment. High Ge concentrations in coals have been considered to be a function of seam thickness and proximity to the top and bottom of the coal bed. Thin coals, such as the Amos, are dominated by the coal bed margins and, therefore, have a tendency to have relatively high Ge concentrations. In the case of the Amos coal bed, the lower bench has a higher Ge content, suggesting that the substrate was a more important source of Ge than the roof rock. ?? 2002 Elsevier Science B.V. All rights reserved.

  9. Sequential solvent extraction for the modes of occurrence of selenium in coals of different ranks from the Huaibei Coalfield, China.

    PubMed

    Zhang, Ying; Liu, Guijian; Chou, Chen-Lin; Wang, Lei; Kang, Yu

    2007-12-20

    Forms of selenium in bituminous coal, anthracite, and cokeite (natural coke) from Huaibei Coalfield, Anhui, China, have been determined by sequential solvent extraction. The selenium content in bulk samples is 4.0, 2.4, and 2.0 microg/g in bituminous coal, anthracite, and cokeite, respectively. The six forms of selenium determined by six-step solvent extraction are water-leachable, ion-exchangeable, organic matter-associated, carbonate-associated, silicate-associated, and sulfide-associated. The predominant forms of selenium in bituminous coal are organic matter-associated (39.0%), sulfide-associated (21.1%), and silicate bound (31.8%); these three forms account for 92% of the total. The organic matter bound-selenium decrease dramatically from bituminous coal (39.0%) to anthracite (11.6%) and to cokeite (0%), indicating that organic matter bound selenium is converted to other forms during metamorphism of the coal, most likely sulfide-form. The sulfide-associated form increased remarkably from bituminous coal (21.1%) to anthracite (50.4%) and cokeite (54.5%), indicating the formation of selenium sulfide, possibly in pyrite during the transformation of bituminous coal to anthracite and cokeite. The silicate-associated selenium in bituminous coal (31.8%) is much higher than that in anthracite (16.4%) and cokeite (15.8%), indicating that silicate-associated selenium is partly converted to sulfide during metamorphism.

  10. Sequential solvent extraction for the modes of occurrence of selenium in coals of different ranks from the Huaibei Coalfield, China

    USGS Publications Warehouse

    Zhang, Y.; Liu, Gaisheng; Chou, C.-L.; Wang, L.; Kang, Y.

    2007-01-01

    Forms of selenium in bituminous coal, anthracite, and cokeite (natural coke) from Huaibei Coalfield, Anhui, China, have been determined by sequential solvent extraction. The selenium content in bulk samples is 4.0, 2.4, and 2.0 ??g/g in bituminous coal, anthracite, and cokeite, respectively. The six forms of selenium determined by six-step solvent extraction are water-leachable, ion-exchangeable, organic matter-associated, carbonate-associated, silicate-associated, and sulfide-associated. The predominant forms of selenium in bituminous coal are organic matter-associated (39.0%), sulfide-associated (21.1%), and silicate bound (31.8%); these three forms account for 92% of the total. The organic matter bound-selenium decrease dramatically from bituminous coal (39.0%) to anthracite (11.6%) and to cokeite (0%), indicating that organic matter bound selenium is converted to other forms during metamorphism of the coal, most likely sulfide-form. The sulfide-associated form increased remarkably from bituminous coal (21.1%) to anthracite (50.4%) and cokeite (54.5%), indicating the formation of selenium sulfide, possibly in pyrite during the transformation of bituminous coal to anthracite and cokeite. The silicate-associated selenium in bituminous coal (31.8%) is much higher than that in anthracite (16.4%) and cokeite (15.8%), indicating that silicate-associated selenium is partly converted to sulfide during metamorphism. ?? 2007 Zhang et al; licensee BioMed Central Ltd.

  11. Wetland-stream ecosystems of the western Kentucky coalfield: environmental disturbance and the shaping of aquatic community structure

    SciTech Connect

    Hill, P.L. Jr.

    1983-01-01

    The effects of surface mining effluents of the shaping of aquatic community structure in wetland-stream ecosystems of the western Kentucky coalfield were examined. Three variously impacted drainage systems were utilized for the investigation of cause-and-effect relationships. Clear Creek wetland-stream ecosystem had a uniformly low pH, high conductivity and high dissolved minerals load linked to the oozing of old, unreclaimed surface mine spoils. Cypress Creek wetland-stream ecosystem exhibited a slug-pulsing of mine drainage effluents tied to active surface mining limited to the headwaters region. Henderson Sloughs-Pond Creek wetland-stream ecosystem had no mining impact and was utilized as a comparison site. Macroinvertebrate taxa and diversity were considerably lowered in the systems receiving mine drainage. The Shannon-Weaver diversity index (H) was 0.61 for Clear Creek, 1.80 for Cypress Creek and 2.01 for Henderson Sloughs. Large numbers of chironomid larvae dominated the benthic community of Clear Creek while mayflies, caddisflies and crustaceans were the major components of the Cypress Creek community. Henderson Sloughs-Pond Creek had an even more diverse community of mayflies, caddisflies, crustaceans, molluscs and odonates. Fishes followed the same general trend, being almost absent in Clear Creek (H - 0.47), slightly depressed in Cypress Creek (H = 1.74) and generally diverse in Henderson Sloughs (H = 2.37).

  12. Effects of fracturing on well yields in the coalfield areas of Wise and Dickenson counties, southwestern Virginia

    USGS Publications Warehouse

    Wright, W.G.

    1985-01-01

    Fracturing associated with lineaments are the primary influence on yields from wells in the coalfields of southwestern Virgnia. Graphical comparison of yield from wells shows that wells located in valleys with lineaments produce larger quantities of water than wells in valleys without lineaments. Pumping tests at wells located in valleys with lineaments indicate transmissivities as high as 598 ft2/d, caused principally by secondary permeability. Analysis of data collected from packer-injection tests in a test hole located on a ridge indicate relatively large hydraulic conductivities ranging from 2x10(sup -2) to 1x10(sup -1) feet per day in upper parts of the test hole, compared to values typical of unfractured rocks in the study area. Fracturing due to stress relief contribute to these large values. Yields from wells located on lineaments are consistently higher than well yields from wells in unfractured rock in the study area, but well yields from wells placed randomly in areas suspected of having stress relief fractures cannot be predicted. (USGS)

  13. Biomagnification of naturally-produced methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in harbour seals and harbour porpoises from the southern North Sea.

    PubMed

    Weijs, Liesbeth; Losada, Sara; Das, Krishna; Roosens, Laurence; Reijnders, Peter J H; Santos, Javier F; Neels, Hugo; Blust, Ronny; Covaci, Adrian

    2009-08-01

    Harbour seals and harbour porpoises are top predator species from the North Sea, have long life spans and hence, are known to accumulate high levels of anthropogenic contaminants. To gain knowledge about the behaviour of naturally-produced compounds in these marine mammals, the biomagnification of naturally-produced methoxylated polybrominated diphenyl ethers (MeO-PBDEs) was assessed. The biomagnification of MeO-PBDEs (2'-MeO-BDE 68 and 6-MeO-BDE 47) was lower in harbour seals (all biomagnification factors (BMFs)<1) compared to the same age-gender groups of the harbour porpoises (all BMFs>1). This may indicate a better metabolic breakdown of MeO-PBDEs in harbour seals, as was previously suggested for polybrominated diphenyl ethers (PBDEs). In both predators, 6-MeO-BDE 47 had the highest concentrations (range: 45-483 ng/g lw and 2-38 ng/g lw for harbour porpoises and seals, respectively) compared to 2'-MeO-BDE 68 (range: 2-28 ng/g lw and 1-6 ng/g lw for harbour porpoises and seals, respectively). In general, the highest concentrations were found in juveniles, suggesting an increased biotransformation capacity with age or the influence of dilution by growth for both species. Here we show that naturally-produced brominated organic compounds can biomagnify and accumulate in North Sea top predators, although to a lesser extent than anthropogenic lipophilic contaminants, such as polychlorinated biphenyls (PCBs) or PBDEs.

  14. Accretion of southern Alaska

    USGS Publications Warehouse

    Hillhouse, J.W.

    1987-01-01

    Paleomagnetic data from southern Alaska indicate that the Wrangellia and Peninsular terranes collided with central Alaska probably by 65 Ma ago and certainly no later than 55 Ma ago. The accretion of these terranes to the mainland was followed by the arrival of the Ghost Rocks volcanic assemblage at the southern margin of Kodiak Island. Poleward movement of these terranes can be explained by rapid motion of the Kula oceanic plate, mainly from 85 to 43 Ma ago, according to recent reconstructions derived from the hot-spot reference frame. After accretion, much of southwestern Alaska underwent a counterclockwise rotation of about 50 ?? as indicated by paleomagnetic poles from volcanic rocks of Late Cretaceous and Early Tertiary age. Compression between North America and Asia during opening of the North Atlantic (68-44 Ma ago) may account for the rotation. ?? 1987.

  15. [North] Yemen.

    PubMed

    1987-11-01

    The Yemen Arab Republic, also called North Yemen, is a small republic on the southern tip of the Arabian peninsula facing the Red Sea. Yemen has a temperate interior suitable for agriculture. 8.7 million people of Semetic Arab origin are growing at a rate of 3.1% yearly. The infant mortality rate is 173/1000; the life expectancy is 44 years, and the per capita income is about $550. Yemen was once self-sufficient in food production, exporting fine coffee. Years of civil wars, emigration to Saudi Arabia for work, production of the cash crop "qat" for internal consumption, and the recent drought have contributed to the decline of agriculture. Yemen's economy is maintained by foreign aid from Saudi Arabia, the Soviet Union, China, and the United States. U.S. aid has centered around food, roads and other development projects and primary health care such as immunization and reduction of child mortality.

  16. Forests of North Carolina, 2013

    Treesearch

    Mark J. Brown

    2015-01-01

    This periodic resource update provides an overview of forest resources in North Carolina based on an inventory conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program at the Southern Research Station in cooperation with the North Carolina Forest Service. Data estimates are based on field data collected using the FIA annualized sample design...

  17. Forests of North Carolina, 2014

    Treesearch

    Mark Brown; Samuel Lambert

    2016-01-01

    This periodic resource update provides an overview of forest resources in North Carolina based on an inventory conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program at the Southern Research Station in cooperation with the North Carolina Forest Service. Data estimates are based on field data collected using the FIA annualized sample design...

  18. Latitudinal fractionation of polychlorinated biphenyls in surface seawater along a 62 degrees N-89 degrees N transect from the southern Norwegian Sea to the North Pole area.

    PubMed

    Sobek, Anna; Gustafsson, Orjan

    2004-05-15

    Surface seawater concentrations of PCBs, relative congener abundance, and possible effects of cold condensation were studied along a transect from the southern Norwegian Sea to the central Arctic Ocean (62 degrees N-89 degrees N). Large volume samples were collected from an ice breaker using a stainless steel surface seawater intake connected online to an ultra-clean laboratory. Concentrations of all studied PCB congeners, except for trichlorinated PCB 18, decreased with latitude. For instance, PCB 52 decreased from 470 fg L(-1) at 62 degrees N to 110 fg L(-1) at 89 degrees N and PCB 180 from 110 to 12 fg L(-1). Concentrations in the central Arctic Ocean were on the order of 10-100 fg L(-1) for the most abundant congeners. The relative contribution oftrichlorinated PCBs to the total PCB concentration increased with latitude, the tetrachlorinated contribution to the total PCBs did not show any correlation to latitude, and the relative contribution of heavier congeners decreased with latitude. This study establishes the occurrence at very low abundances of PCBs in seawater in the central Arctic Ocean and demonstrates a northward concentration decrease. The latitudinal shift in congener pattern is reflecting the relative propensity of the PCB congeners to undergo long-range transport in the Arctic and is consistent with their relative vapor pressures.

  19. Using non-invasive methods to characterize gonadal hormonal patterns of southern three-banded armadillos (Tolypeutes matacus) housed in North American zoos.

    PubMed

    Howell-Stephens, J; Bernier, D; Brown, J S; Mulkerin, D; Santymire, R M

    2013-05-01

    Understanding the basic reproductive biology and limitations to successful breeding of the southern three-banded armadillo (Tolypeutes matacus) is necessary to maintain viable zoo populations. Our objectives were to: 1) describe the reproductive biology using non-invasive, fecal hormone analysis; 2) assess influence of season on gonadal hormonal patterns in both the sexes; 3) characterize reproductive cyclicity and pregnancy in the female; and 4) characterize the onset of sexual maturity in males. Nineteen armadillos were monitored including: 13 (7 males, 6 females) from Lincoln Park Zoo and six (3 males, 3 females) from San Antonio Zoological Garden. Fecal samples (n=5220; 275/animal/yr) were collected 5 to 7 times a week for 1 year. Hormones were extracted from feces and analyzed for progestagen (females) and androgen (males) metabolite concentrations using enzyme immunoassays. Mean estrous cycle length (26.4±1.3 days) did not vary (P<0.05) among individuals (n=9). Mean gestation length (n=3) was 114.0±0.6 days long with mean fecal progestagen metabolites increasing 10-fold during pregnancy. Seasons did not influence (P<0.05) fecal androgen or progestagen metabolites. These data can assist with management decisions, which will directly affect the success of this species in zoos. Published by Elsevier B.V.

  20. Modified Gulf of California model for South Georgia,north Scotia Ridge, and implications for the Rocas Verdes back-arc basin, southern Andes

    NASA Astrophysics Data System (ADS)

    Alabaster, T.; Storey, B. C.

    1990-06-01

    New field mapping and an integrated trace element and Nd isotopic study have been undertaken on the Jurassic-Cretaceous Larsen Harbour Complex on the island of South Georgia, recognized as a displaced part of the southern Andes ensialic, autochthonous Rocas Verdes marginal basin. Five basalt groups (Groups I-V) are identified from trace element data; initial Nd isotopic compositions suggest that they are derived from only two sources. Magmas produced during early stages of continental lithospheric attenuation (Groups I-III) were derived by varying degrees of partial melting and fractional crystallization from a large ion lithophile element (LILE)-enriched, low-ɛNd mantle source relative to normal (N)-type mid-ocean ridge basalt (MORB). Magmas produced during later stages of rifting (Groups IV and V) were, however, derived from a high-ɛNd asthenospheric mantle source similar to N-type MORB, unaffected by earlier LILE enrichment. Our data do not concur with previous suggestions that the Larsen Harbour Complex and, by implication, the Rocas Verdes formed in a supra-subduction-zone setting. On the basis of geologic and geochemical evidence, we favor basin formation along an oblique-slip margin akin to that of the Gulf of California.

  1. Preliminary estimate of coal resources in the Gillette coalfield affected by the location of the Burlington Northern/Union Pacific joint mainline railroad

    USGS Publications Warehouse

    Rohrbacher, Timothy J.; Haacke, Jon E.; Scott, David C.; Osmonson, Lee M.; Luppens, James A.

    2006-01-01

    This publication, primarily in graphic form, presents a preliminary resource assessment related to a major, near-term restriction to mining in that portion of the Gillette coalfield, Wyoming, that is traversed by the Burlington Northern/Union Pacific joint mainline railroad. This assessment is part of a current Powder River Basin regional coal assessment, including both resources and reserves, being conducted by the U.S. Geological Survey. The slides were used to illustrate a presentation of study results at a meeting of the Bureau of Land Management's Regional Coal Team in Casper, Wyoming on April 19, 2006 by the senior author.

  2. Nitrous oxide cycling in the water column and sediments of the oxygen minimum zone, eastern subtropical North Pacific, Southern California, and Northern Mexico (23°N-34°N)

    NASA Astrophysics Data System (ADS)

    Townsend-Small, Amy; Prokopenko, Maria G.; Berelson, William M.

    2014-05-01

    Identifying sources and sinks of N2O can illuminate N cycling processes in marine systems, particularly where changes in dissolved O2 can lead to changes in N cycling pathways (i.e., nitrification versus denitrification). We measured N2O and NO3- concentration and their stable isotope ratios (δ15N and δ18O) in the water column and sediments of the oxygen minimum zone in the nearshore eastern subtropical North Pacific (23°N-34°N). Atmospheric efflux of N2O ranged from 2.2 to 17.9 μmol m-2 d-1 or about 2-20 times higher than in oxygenated regions of the North Pacific. Surface waters were a source of 15N-depleted and 18O-enriched N2O to the atmosphere, indicating a bacterial, not archaeal, nitrification N2O source. Stable isotopes indicated that nitrification in both surface and intermediate waters (˜0-200 m) was the major source of N2O in this study area, with denitrification acting as a small N2O sink in strongly O2-depleted waters. Denitrification had a larger impact on observed patterns of N2O and NO3- concentrations and isotope ratios in the southern oxygen minimum zone. Sediments were generally neutral or a weak sink for N2O, with only one site (Soledad basin) showing a positive efflux of +3.5 ± 1.0 μmol N2O-N m-2 d-1. Sediment fluxes of N2O at all sites were several orders of magnitude smaller than fluxes of dinitrogen, nitrate, and ammonium measured in previous studies and did not appear to impact water column N2O concentrations. N2O was less than 0.1% of the N2 efflux from sedimentary denitrification.

  3. Prevalence of antibodies to Trypanosoma cruzi, Toxoplasma gondii, Encephalitozoon cuniculi, Sarcocystis neurona, Besnoitia darlingi, and Neospora caninum in North American opossums, Didelphis virginiana, from southern Louisiana.

    PubMed

    Houk, Alice E; Goodwin, David G; Zajac, Anne M; Barr, Stephen C; Dubey, J P; Lindsay, David S

    2010-12-01

    We examined the prevalence of antibodies to zoonotic protozoan parasites ( Trypanosoma cruzi, Toxoplasma gondii, and Encephalitozoon cuniculi) and protozoans of veterinary importance ( Neospora caninum, Sarcocystis neurona, and Besnoitia darlingi) in a population of North American opossums ( Didelphis virginiana) from Louisiana. Samples from 30 opossums were collected as part of a survey for T. cruzi in Louisiana. Frozen sera from these 30 opossums were examined using an indirect immunofluorescent antibody test (IFAT) against in vitro-produced antigenic stages of these protozoans. Additionally, 24 of the 30 samples were examined using hemoculture, and all 30 were examined in the modified direct agglutination test (MAT) for antibodies to To. gondii. The prevalences of reactive IFAT samples were as follows: 60% for T. cruzi, 27% for To. gondii, 23% for E. cuniculi, 17% for S. neurona, 47% for B. darlingi, and 0% for N. caninum. Hemoculture revealed that 16 (67%) of 24 samples were positive for T. cruzi, compared to 18 of 30 (60%) by IFAT. The sensitivity and specificity for the IFAT compared to hemoculture was 100% for each. The modified direct agglutination test revealed that 9 (30%) of the 30 samples from opossums had antibodies to To. gondii , compared to 8 (27%) using the IFAT. The sensitivity and specificity of the IFAT compared to the MAT was 100% and 72%, respectively.

  4. Deformation above mobile substrates, salt rheology and spatial distribution of salt structures: A 3D seismic study of the Permian southern North Sea

    NASA Astrophysics Data System (ADS)

    Hernandez, Karina; Mitchell, Neil; Huuse, Mads

    2016-04-01

    At ~255 Ma, cycles of evaporation of seawater led to deposition of evaporites including halite (rock salt) in the North Sea Basin. After later burial by denser sediments, the salt beds rose as pillows and diapirs. Assuming mobilization is due to Rayleigh-Taylor gravitational instability of heavy fluid (sediments) overlying light fluid (salts), theory suggests that the spacing between diapirs should be proportional to the original thickness of the salt layer. For example, a description of the theory in Turcotte and Schubert (1982) predicts structure wavelength to be 2.6 times the salt thickness. Previous research has explored mobilization of salt deposits assuming they have uniform rheology. However, this is not justified as halite rheology varies with temperature, grain size and pore brine content. Furthermore, evaporitic sequences contain various minerals besides halite (e.g., anhydrite, gypsum), which have different rheological properties. 3D seismic and well data reveal the internal structure of salt beds. The data have allowed characterization of structure wavelengths and salt thickness, so that the impact of internal composition and other properties on halokinetic behaviour can be assessed.

  5. Integrating the pre-LGM Stalagmite Record from the Southern Appalachians of Eastern North America with Tropical, East Asian, and Greenland Paleoclimate Records

    NASA Astrophysics Data System (ADS)

    Rowe, H. D.; Gao, Y.; Buckles, J. A.; Springer, G. S.; Cheng, H.; Edwards, R.; Hardt, B. F.

    2011-12-01

    New stable isotopic (δ13C, δ18O) and trace metal (Sr/Ca) results from a 230Th-dated stalagmite whose growth spanned MIS 5e to just before the LGM (at approximately DO event #2) reveal strong linkages with the isotopic records from Greenland and the Asian Monsoon region, and geochemical/color proxies from the tropics (Cariaco Basin). While the stalagmite δ18O record largely reflects precession-driven shifts in the seasonality of precipitation, the δ13C and Sr/Ca curves are better characterized as records of gradual change from wet to dry, punctuated by abrupt spells of aridity. The timings of the shifts in the moisture balance proxies largely coincide with well-documented shifts observed in the Greenland, Asian Monsoon, and Cariaco records---especially the timing of the DO events. This suggests that the climate of eastern North America is responsive to well-defined shifts in the amount of precipitation that are intimately linked with global-scale shifts in tropical variability, monsoonal moisture and polar temperature instability.

  6. The north-eastern aeolian 'European Sand Belt' as potential record of environmental changes: A case study from Eastern Latvia and Southern Estonia

    NASA Astrophysics Data System (ADS)

    Kalińska-Nartiša, Edyta; Thiel, Christine; Nartišs, Māris; Buylaert, Jan-Pieter; Murray, Andrew S.

    2016-09-01

    The Latvian and Estonian inland dunes belong to the north-eastern part of the 'European Sand Belt' (ESB). These dunes are widely distributed over broad glaciolacustrine plains and Late Glacial alluvial deltas, considered to be potential sources for the aeolian material. Little is known about these aeolian sediments and their substratum; here we present a detailed sedimentary structural and textural characterisation together with a luminescence-based chronology. Through a comparison between grain-size, rounding of quartz grains and surface characteristics in medium/coarse (0.5-0.8 mm) sand, and the light mineral content, we found an alternation of aeolian and periglacial components. Further, short-lasting aeolian abrasion and/or transportation periods, and a significant contribution of a nearby sediment source are suggested. Luminescence dating points to aeolian sand accumulation and dune formation between ∼16 ka and ∼9 ka. However, we also observed some presumably watertable controlled environmental conditions at ∼13 ka; this corresponds with the occurrence of an ice-dammed/proglacial lake.

  7. A research on coalfield fire detection in Daliuta mining area at Inner Mongolia based on hyperspectral thermal infrared remote sensing

    NASA Astrophysics Data System (ADS)

    Yang, Guo-fang; Zhou, Jia-jing; Tian, Xin-guang

    2016-10-01

    Daliuta mining coal fires at Inner Mongolia were not reported at present in remote sensing. However, they still pose a serious threat to the surroundings. In order to extract combustion range of the coal mine, we used the wintertime thermal airborne infrared hyperspectral images of TASI acquired in 2016 to detect the coal fire of Daliuta mining. The synchronous in situ measured temperature was used to establish space-to-ground regression equation with the image temperature for retrieving land surface temperature. Extracted coal fire through the reasonable threshold by the processed image data, identified a region where the surface temperatures was -0.5°C to 300°C. MODTRAN4 code was used to estimate the upward and downward radiation and transmission of the atmosphere. On this basis, the non-coal fire anomaly areas, such as the cooling water of power plant, heat buildings, chimney, were separated from the coal fire heat anomaly areas by the characteristic difference of the emissivity spectrum in the objectives. The results show that the bands 1-16 of TASI are suitable for infrared inversion temperature for the coalfield fire. There was a linear relationship between synchronous in situ observation temperature and the image temperature, and the determination coefficient R2 was 0.9938. The extracted coal fire anomaly range is able to provide some decision support for underground coal fire extinguishing. A detailed fire map of shallow coal areas can help to prioritize fire fighting operations in order to avoid the chance of starting a new coal fire.

  8. Changes in Ecosystem Carbon Following Afforestation of Post-Mining Sites- A Case Study from Raniganj Coalfield, India

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Maiti, S. K.; Chaudhuri, S.; Ghosh, P.

    2015-12-01

    The concept of changes in ecosystem dynamics of carbon (C) as a function of soil and vegetation developments at post-mining sites is of interest because of its prospective function in mitigating increasing global C-cycle. Forestry reclamation approaches (FRA) for post-mining sites can significantly enhance C storage in minesoils and established species; however the mechanism that not widely assessed to predict changes in ecosystem functions. A chronosequence post-mining sites (2-years, 5-years, 9-years, 15-years and 21-years old reclaimed afforested minesoils at Raniganj Coalfield, India) were investigated to: (i) quantify the amount of soil C accumulating in developing ecosystem; (ii) examine several physiochemical properties and biological processes that govern the rate of C-sequestration; (iii) identify the relationships between C-sequestration and soil properties, and (iv) develop a soil quality index by principal component analysis (PCA). From changes in ecosystem C perspective, although soil organic carbon (Corg) was less in newly developed ecosystem in comparisons to older one (21-years). However, rate of soil C-accumulation was greater (2.6 Mg C ha-1yr-1) in newly formed minesoil ecosystem. The overall microbial indices, dehydrogenase activities (DHA-15.7 µg-1TPF g-1 24 hrs-1); microbial biomass carbon (MBC-368 mg C kg-1); and rates of soil CO2 flux (15 μmol CO2 m-2 s-1) were found highest in older minesoils in comparisons to younger minesoils. PCA showed that three PCs with eigenvalues > 1 explained 74.5% of the total variance in the soil properties. The first PC is mostly characterized by soil nutritional and biological properties; second PC by physical properties and showed a positive correlation with soil C-accumulation and changes in plant species diversity. The present study showed that changes in ecosystem C and nutrients are direct function of enhanced and established forest land use managements.

  9. A Geochemical Investigation of the Early Cretaceous Ultrapotassic Dykes in the Raniganj Coalfields in Damodar Valley, India

    NASA Astrophysics Data System (ADS)

    Jude, T. A.

    2015-12-01

    The early Cretaceous ultrapotassic dyke rocks intruding the Permocarboniferous coal bearing Gondwana sediments of the Eastern Damodar Valley, Singhbum craton, are known for their petrographic and geochemical diversity. They remain a 'Pandora's box of petrological confusion' with a variety of exotic, and potentially diamondiferous, rocks such as lamprophyre, lamproite, orangeite and kimberlite being continuously reported from them for over one century or more. Intra-plate volcanism of this type discloses hidden information about the interior of the Earth. Samples from two dykes intruding Raniganj coalfield is studied here. The samples from Dyke1 are characterized by fine grained texture and phlogopite+apatite+K-feldspar+rutile+ankerite+dolomite+ chromite+chlorite+quartz assemblage while the samples from Dyke2 are characterized by coarse grained texture and phlogopite+ pseudomorphosed-olivine+apatite+ clinopyroxene +dolomite+ankerite+calcite+norsethite+talc+rutile+quartz+Ca-Mg-Fe-Zr silicate+K-feldspar+monazite+ perovskite assemblage. Based on the TiO2-Al2O3-FeO trends observed in phlogopites, the dykes seem to be a lamproite-orangeite transitional variety. The phlogopites observed in Dyke2 show two stages of crystallization defined by Ti-poor overgrowths on Ti-rich cores indicating that Dyke2 consolidated from a melt that fractionated from a magma which was initially emplaced at a different depth while the Dyke 1 phlogopites do not show any such sudden drop in Ti concentration in their rims indicating single stage crystallization. Ti-in-Quartz Thermometry yields temperatures between 769°C to 1115°C for Dyke1 and 779°C to 1019°C for Dyke2 which must corresponds to the emplacement and crystallization of these dykes. Trace element and isotopic ratios can be used to constrain particular mantle source characteristics of the dykes. Rb-Sr method can be used to determine the emplacement ages of these dykes.

  10. Failure and Redemption of Multifilter Rotating Shadowband Radiometer (MFRSR)/Normal Incidence Multifilter Radiometer (NIMFR) Cloud Screening: Contrasting Algorithm Performance at Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) and Southern Great Plains (SGP) Sites

    SciTech Connect

    Kassianov, Evgueni I.; Flynn, Connor J.; Koontz, Annette S.; Sivaraman, Chitra; Barnard, James C.

    2013-09-11

    Well-known cloud-screening algorithms, which are designed to remove cloud-contaminated aerosol optical depths (AOD) from AOD measurements, have shown great performance at many middle-to-low latitude sites around the world. However, they may occasionally fail under challenging observational conditions, such as when the sun is low (near the horizon) or when optically thin clouds with small spatial inhomogeneity occur. Such conditions have been observed quite frequently at the high-latitude Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) sites. A slightly modified cloud-screening version of the standard algorithm is proposed here with a focus on the ARM-supported Multifilter Rotating Shadowband Radiometer (MFRSR) and Normal Incidence Multifilter Radiometer (NIMFR) data. The modified version uses approximately the same techniques as the standard algorithm, but it additionally examines the magnitude of the slant-path line of sight transmittance and eliminates points when the observed magnitude is below a specified threshold. Substantial improvement of the multi-year (1999-2012) aerosol product (AOD and its Angstrom exponent) is shown for the NSA sites when the modified version is applied. Moreover, this version reproduces the AOD product at the ARM Southern Great Plains (SGP) site, which was originally generated by the standard cloud-screening algorithms. The proposed minor modification is easy to implement and its application to existing and future cloud-screening algorithms can be particularly beneficial for challenging observational conditions.

  11. Phytopigments and fatty acids in the gut of the deposit-feeding heart urchin Echinocardium cordatum in the southern North Sea: Selective feeding and its contribution to the benthic carbon budget

    NASA Astrophysics Data System (ADS)

    Boon, Arjen R.; Duineveld, Gerard C. A.

    2012-01-01

    As part of a broader study on benthic-pelagic coupling in the southern North Sea, specimens of the common heart urchin Echinocardium cordatum were sampled for analyses on phytopigments and fatty acids in their guts. Results were interpreted in the context of feeding and ecological functioning of the heart urchins in the benthic system. Ingestion selection factors for both component groups were relatively high, 5 to 9 for chlorophyll a and 9 to 130 for total fatty acids. The data point to at least partially different sources of the pigments and of the fatty acids. Next to algal detritus, small infauna relatively rich in fatty acids might be preferentially co-ingested with the detritus. Due to digestive breakdown and absorption, the concentrations of pigments and fatty acids were importantly decreased, indicating a rather high digestion efficiency for this subsurface deposit feeder, up to 80%. The results indicate that E. cordatum increases its energy acquisition by strong selectivity and a high digestive efficiency. Optimal foraging is likely to apply on deposit-feeding invertebrates in relatively food-rich coastal environments as much as it does in the food-poor deep-sea environment. Using chlorophyll a as a proxy for carbon, the contribution of the urchin population to the momentary benthic carbon budget was calculated at 7% to 42%.

  12. Volcanic activities in the Southern part of East African rift initiation: Melilitites and nephelinites from the Manyara Basin (North Tanzania rift axis)

    NASA Astrophysics Data System (ADS)

    Baudouin, Celine; Parat, Fleurice; Tiberi, Christel; Gautier, Stéphanie; Peyrat, Sophie

    2016-04-01

    The East African Rift exposes different stages of plate boundary extension, from the initiation of the rift (North (N) Tanzania) to oceanic accretion (Afar). The N Tanzania rift-axis (north-south (S) trend) is divided into 2 different volcanic and seismic activities: (1) the Natron basin (N) with shallow seismicity and intense volcanism and (2) the Manyara basin (S) with deep crustal earthquakes and sparse volcanism. The Natron basin is characterized by extinct volcanoes (2 Ma-0.75 Ma) and active volcano (Oldoinyo Lengai) and a link between seismicity and volcanism has been observed during the Oldoinyo Lengai crisis in 2007. In the S part of the N Tanzanian rift, volcanoes erupted in the Manyara basin between 0.4 and 0.9 Ma. In this study, we used geochemical signature of magmas and deep fluids that percolate into the lithosphere beneath Manyara basin, to define the compositions of magmas and fluids at depth beneath the S part of the N Tanzania rift, compare to the Natron basin and place constrain on the volcanic and seismic activities. The Manyara basin has distinct volcanic activities with mafic magmas as melilitites (Labait) and Mg-nephelinites (carbonatite, Kwaraha), and more differentiated magmas as Mg-poor nephelinites (Hanang). Melilitites and Mg-nephelinites are primary magmas with olivine, clinopyroxene (cpx), and phlogopite recording high-pressure crystallization environment, (melilitites >4 GPa and Mg-nephelinites>1 GPa) with high volatile contents (whole rock: 0.7-4.6 wt% CO2, 0.1-0.3 wt% F and 0.1 wt% Cl). FTIR analyses of olivine constrained the water content of Labait and Kwaraha magmas at 0.1 and 0.4 wt% H2O, respectively. Geochemical modelling suggests that mafic magmas result from a low degree of partial melting (1-2%) of a peridotitic source with garnet and phlogopite (high Tb/Yb (>0.6) and Rb/Sr (0.03-0.12) ratio). Mg-poor nephelinites from Hanang volcano crystallized cpx, Ti-garnet, and nepheline as phenocrysts. Magmas result from fractional

  13. Age and zircon inheritance of eastern Blue Ridge plutons, southwestern North Carolina and northeastern Georgia, with implications for magma history and evolution of the southern Appalachian origin

    SciTech Connect

    Miller, C.F.; Hatcher, R.D. Jr.; Ayers, J.C.; Coath, C.D.; Harrison, T.M.

    2000-02-01

    High-resolution ion microprobe analysis of zircon has provided ages for previously undated plutons of the high-grade eastern Blue Ridge of northeastern Georgia and southwestern North Carolina. These data, together with backscattered electron imaging, reveal the presence of nearly ubiquitous inherited cores of highly variable age and magmatic rims that have experienced variable Pb loss, thus making interpretation of conventional U-Pb analyses very difficult. Ion probe rim analyses indicate that the plutons were emplaced during both the mod-Ordovician and mid-Devonian. Zircons from all intrusions have predominantly 1.0 to 1.25 Ga cores (Grenvillian). In addition, both Devonian and Ordovician plutons have smaller populations of Late Proterozoic-early Paleozoic (0.5--0.75 Ga), Middle Proterozoic (1.4 Ga), and Late Archean (2.6--2.9 Ga) cores. The ubiquitous, round cores and thick magmatic rims suggest significant resorption and then protracted growth within the melts. Zircon saturation temperatures based on whole-rock ({approximately}melt) Zr concentrations are lower than expected for magma generation (710--760 C). Zirconium concentrations may not reflect saturation at maximum temperature, if melting was very rapid (<{approximately}10{sup 5} yrs), or if zircon cores represent grains that were shielded from melt inside host grains for much of the magmatic history. Ages of magmatic and inherited zones of zircon from the plutons demonstrate that similar crust underlay the eastern Blue Ridge during both Taconian and Acadian orogenies, that there was no single episode of voluminous magmatism, and that metamorphism and deformation began before 470 Ma and continued after 370 Ma. These plutons do not constitute a significant convergence-related arc, though it is possible that they represent a displaced part of an arc that lies primarily to the east (in the Inner Piedmont?).