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Sample records for 183-dr sedimentation basin

  1. Remaining Sites Verification Package for the 100-D-50:5 Process Sewers (183-DR Sedimentation Basin Drains), Waste Site Reclassification Form 2006-025

    SciTech Connect

    L. M. Dittmer

    2007-11-06

    The 100-D-50:5 subsite encompasses the southern process sewers formerly servicing the 183-DR coagulation and sedimentation basins and proximate surface runoff collection drains. The results of confirmatory sampling of pipeline sediments and underlying soils at the 100-D-50:5 subsite demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.

  2. Characterization Activities Conducted at the 183-DR Site in Support of an In Situ Gaseous Reduction Demonstration

    SciTech Connect

    Thornton, Edward C.; Gilmore, Tyler J.; Olsen, Khris B.; Schalla, Ronald; Cantrell, Kirk J.

    2001-03-30

    In Situ Gaseous Reduction (ISGR) is a technology developed by DOE for the remediation of soil waste sites contaminated with hexavalent chromium. This document presents information associated with characterization activities conducted at the 183-DR site at Hanford, which is associated with a significant groundwater contaminant plume and was formerly a water treatment facility that utilized chromate as a corrosion inhibitor. Geotechnical and chemical data were collected during the excavation of trenches and the drilling of two vadose zone boreholes to support a possible ISGR demonstration at 183-DR. Although elevated total chromium and trace levels of hexavalent chromium were identified from one of the trenches and one of the boreholes, it appears that the boreholes missed the vadose zone contaminant source responsible for the chromium groundwater plume located downgradient of the 183-DR site. Recommendations are provided, however, for future work at 183-DR that may serve to identify the source for the groundwater plume and possibly provide an opportunity for an ISGR demonstration.

  3. Description of Work for Drilling at the 183-DR Site in Support of the In Situ Gaseous Reduction Test

    SciTech Connect

    Thornton, Edward C.; Olsen, Khris B.; Schalla, Ronald

    2000-06-26

    In Situ Gaseous Reduction is a technology currently being developed by DOE for the remediation of soil waste sites contaminated with hexavalent chromium. Prior work suggests that a candidate for application of this approach is the 183-DR site at Hanford. However, deep vadose zone drilling is needed to verify the presence of a hexavalent chromium source and to determine the concentration levels and spatial distribution of contamination. This document presents the requirements associated with drilling one to two vadose zone boreholes at the 183-DR site to obtain this information. If hexavalent chromium is determined to be present at levels of at least 10 ppm in the vadose zone in one of the initial boreholes, this hole will be completed for gas injection and six additional gas extraction boreholes will be drilled and completed. This network will be used as a flowcell for performing a gas treatment test at the site.

  4. Modelling sediment input in large river basins

    NASA Astrophysics Data System (ADS)

    Scherer, U.

    2012-04-01

    Erosion and sediment redistribution play a pivotal role in the terrestrial ecosystem as they directly influence soil functions and water quality. In particular surface waters are threatened by emissions of nutrients and contaminants via erosion. The sustainable management of sediments is thus a key challenge in river basin management. Beside the planning and implementation of mitigation measures typically focusing on small and mesoscale catchments, the knowledge of sediment emissions and associated substances in large drainage basins is of utmost importance for water quality protection of large rivers and the seas. The objective of this study was thus to quantify the sediment input into the large drainage basins of Germany (Rhine, Elbe, Odra, Weser, Ems, Danube) as a basis for nutrient and contaminant emissions via erosion. The sediment input was quantified for all watersheds of Germany and added up along the flow paths of the river systems. Due to the large scale, sediment production within the watersheds was estimated based on the USLE for cultivated land and naturally covered areas and on specific erosion rates for mountainous areas without vegetation cover. To quantify the sediment delivery ratio a model approach was developed using data on calculated sediment production rates and long term sediment loads observed at monitoring stations of 13 watersheds located in different landscape regions of Germany. A variety of morphological parameters and catchment properties such as slope, drainage density, share of morphological sinks, hypsometric integral, flow distance between sediment source areas and the next stream as well as soil and land use properties were tested to explain the variation in the sediment delivery ratios for the 13 watersheds. The sediment input into streams is mainly controlled by the location of sediment source areas and the morphology along the flow pathways to surface waters. Thus, this complex interaction of spatially distributed catchment

  5. Stormwater detention basin sediment removal

    SciTech Connect

    Gross, W.E.

    1995-12-31

    In the past, stormwater runoff from landfills has been treated mainly by focusing on reducing the peak storm discharge rates so as not to hydraulically impact downstream subsheds. However, with the advent of stricter water quality regulations based on the Federal Clean Water Act, and the related NPDES and SPDES programs, landfill owners and operators are now legally responsible for the water quality of the runoff once it leaves the landfill site. At the Fresh Kills Landfill in New York City, the world`s largest covering over 2000 acres, landfilling activities have been underway since 1945. With the main objective at all older landfill sites having focused on maximizing the available landfill footprint in order to obtain the most possible airspace volume, consideration was not given for the future siting of stormwater basin structures. Therefore, when SCS Engineers began developing the first comprehensive stormwater management plan for the site, the primary task was to locate potential sites for all the stormwater basins in order to comply with state regulations for peak stormwater runoff control. The basins were mostly constructed where space allowed, and were sized to be as large as possible given siting and subshed area constraints. Seventeen stormwater basins have now been designed and are being constructed to control the peak stormwater runoff for the 25-year, 24-hour storm as required by New York State. As an additional factor of safety, the basins were also designed for controlled discharge of the 100-year, 24 hour storm.

  6. Sediment thickness in the southern Canada Basin

    USGS Publications Warehouse

    May, S.D.; Grantz, A.

    1990-01-01

    Multichannel seismic reflection data are used, in conjunction with deep crustal seismic refraction data, to estimate the thickness of sediments in the southern Canada Basin of the Arctic Ocean north of Alaska. The sediments are interpreted to be of Hauterivian (mid-Early Cretaceous) to Holocene age. Comparison of the seismic reflection character of seismic reflections in the study area with that in other basins indicates that a base-of-sediment-top of oceanic layer 2 reflection is not present above the depth at which the water-bottom multiple obscures all deeper arrivals, which is in conflict with the conclusions drawn from aeromagnetic, refraction, and other reflection studies. Seismic velocity structure, determined from the reflection data, indicates that the reflections above the multiple are from sedimentary strata. In the absence of seismic reflection evidence for the top of layer 2 above the multiple, we estimate total sediment thickness by using the layer 3 refractions and subtracting an average assumed layer 2 thickness from the top of layer 3. Assuming that an average thickness of oceanic layer 2 (1.4 km) overlies layer 3 in the southern Canada Basin, sediment thickness in the study area is estimated to range between 6.5 km where water depth is 3.8 km to greater than 11 km where the water depth is 2 km. This is nearly double that of any previous estimates and should have a significant effect on calculations such as the age of Canada Basin, regional heat flow, and long-term sedimentation rates. ?? 1990.

  7. Submarine Landslides in Arctic Sedimentation: Canada Basin

    USGS Publications Warehouse

    Mosher, David C.; Shimeld, John; Hutchinson, Deborah R.; Lebedova-Ivanova, N; Chapman, C.

    2016-01-01

    Canada Basin of the Arctic Ocean is the least studied ocean basin in the World. Marine seismic field programs were conducted over the past 6 years using Canadian and American icebreakers. These expeditions acquired more than 14,000 line-km of multibeam bathymetric and multi-channel seismic reflection data over abyssal plain, continental rise and slope regions of Canada Basin; areas where little or no seismic reflection data existed previously. Canada Basin is a turbidite-filled basin with flat-lying reflections correlateable over 100s of km. For the upper half of the sedimentary succession, evidence of sedimentary processes other than turbidity current deposition is rare. The Canadian Archipelago and Beaufort Sea margins host stacked mass transport deposits from which many of these turbidites appear to derive. The stratigraphic succession of the MacKenzie River fan is dominated by mass transport deposits; one such complex is in excess of 132,000 km2 in area and underlies much of the southern abyssal plain. The modern seafloor is also scarred with escarpments and mass failure deposits; evidence that submarine landsliding is an ongoing process. In its latest phase of development, Canada Basin is geomorphologically confined with stable oceanographic structure, resulting in restricted depositional/reworking processes. The sedimentary record, therefore, underscores the significance of mass-transport processes in providing sediments to oceanic abyssal plains as few other basins are able to do.

  8. Sediment fluxes in transboundary Selenga river basin

    NASA Astrophysics Data System (ADS)

    Belozerova, Ekaterina

    2013-04-01

    Gathering reliable information on transboundary river systems remains a crucial task for international water management and environmental pollution control. Countries located in the lower parts of the river basins depend on water use and management strategies in adjacent upstream countries. One important issue in this context is sediment transport and associated contaminant fluxes across the state borders. The mass flows of dissolved ions, biogens, heavy metal concentrations, as far as suspended sediment concentration (SSC, mg/l) along upper Selenga river and its tributaries based on the literature review and results of field campaigns 2011-2012 were estimated. Based on the water discharges measurements Q, suspended load WR (t/day) and dissolved loads WL were calculated. In the Selenga basin the minimal WR (1,34-3,74 t/day) were found at small rivers. Maximal sediment loads (WR = 15 000 t/day) were found at the upper Orkhon river during flood event. The downstream point (Mongolia-Russia border) was characterized 2 220 t/day in 2011. Generally the prevalence of the accumulation is found through calculating sediment budget for all rivers (ΔW = WR (downstream) - WR (upstream) < 0). Downstream of Orkhon river (below confluence with Tuul) ΔW = - 1145 t/day. Below Selenga-Orkhon confluence sediment yield reached 2515 t/day, which is corresponded to transboundary sediment flux. Silt sediments (0,001 - 0,05 mm) form the main portion of the transported material. The maximal value of sand flux (302 t/day) was reported for middle stream station of Selenga river (upstream from confluence with Orkhon). The increase of human activities (mining and pastures) increases the portion of clay particles in total sediment load (e.g. at the downstream point of most polluted Orkhon river it reached 207,8 t/day). The existed estimates are compared with distribution of the main matter sources within basin: mining and industry, river-bank erosion and slope wash. The heaviest increase of

  9. Sedimentation basin performance at highway construction sites.

    PubMed

    Kalainesan, Sujaya; Neufeld, Ronald D; Quimpo, Rafael; Yodnane, Precha

    2009-02-01

    Sedimentation basins (SBs) are commonly used during highway construction for erosion and sedimentation pollution control as well as for attenuation of overland storm waters. In order to evaluate the sediment removal capacity of these SBs, four basins were selected for monitoring from a new highway construction that extends I-99 to I-80, in Pennsylvania. Between September 2004 and August 2005, ten sampling trips were conducted during which basin inlet and outlet water samples were obtained. The SB samples were analyzed for pH, color, turbidity, total suspended solids (TSS), volatile suspended solids (VSS), total and dissolved iron, magnesium, manganese, aluminum, calcium, sulfate and phosphate. The data showed peaks in concentrations of TSS, total aluminum, total manganese, total iron and total phosphate that closely correlated to localized rainfall peaks. For certain samples, the concentration of TSS in the outlet was higher than the TSS concentration at the basin inlet, suggesting sediment re-suspension. In general SBs managed high flows during wet weather events, but were not effective in capturing particulates. This paper discusses the need for Best Management Practices (BMPs) for the design of SBs that reflect contemporary concerns for management of particle removal and to control the release of particulate-bound metals. This paper also evaluates the water quality impacts of naturally occurring acidic drainages into SBs, as several acidic seeps with pH in the range of 5-6 and having high dissolved concentrations of metals (Fe, Mn, Mg and Ca), sulfate and phosphate were observed draining into the SBs.

  10. Sediment Transport in Streams in the Umpqua River Basin, Oregon

    USGS Publications Warehouse

    Onions, C. A.

    1969-01-01

    This report presents tables of suspended-sediment data collected from 1956 to 1967 at 10 sites in the Umpqua River basin. Computations based on these data indicate that average annual suspended-sediment yields at these sites range from 137 to 822 tons per square mile. Because available data for the Umpqua River basin are generally inadequate for accurate determinations of sediment yield and for the definition of characteristics of fluvial sediments, recommendations are made for the collection and analysis of additional sediment data.

  11. View of former preliminary sedimentation basin, looking east from south ...

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

    View of former preliminary sedimentation basin, looking east from south side of low-lift pumping station. - Robert B. Morse Water Filtration Plant, 10700 and 10701 Columbia Pike, Silver Spring, Montgomery County, MD

  12. Selenium in Reservoir Sediment from the Republican River Basin

    USGS Publications Warehouse

    Juracek, Kyle E.; Ziegler, Andrew C.

    1998-01-01

    Reservoir sediment quality is an important environmental concern because sediment may act as both a sink and a source of water-quality constituents to the overlying water column and biota. Once in the food chain, sediment-derived constituents may pose an even greater concern due to bioaccumulation. An analysis of reservoir bottom sediment can provide historical information on sediment deposition as well as magnitudes and trends in constituents that may be related to changes in human activity in the basin. The assessment described in this fact sheet was initiated in 1997 by the U.S. Geological Survey (USGS), in cooperation with the Bureau of Reclamation (BOR), U.S. Department of the Interior, to determine if irrigation activities have affected selenium concentrations in reservoir sediment of the Republican River Basin of Colorado, Kansas, and Nebraska.

  13. Sediment yields of streams in the Umpqua River Basin, Oregon

    USGS Publications Warehouse

    Curtiss, D.A.

    1975-01-01

    This report summarizes sediment data collected at 11 sites in the Umpqua River basin from 1956 to 1973 and updates a report by C. A. Onions (1969) of estimated sediment yields in the basin from 1956-67.  Onions' report points out that the suspended-sediment data, collected during the 1956-67 period, were insufficient to compute reliable sediment yields.  Therefore, the U.S, Geological Survey, in cooperation with Douglas County, collected additional data from 1969 to 1973 to improve the water discharge-sediment discharge relationships at these sites.  These data are published in "Water resources data for Oregon, Part 2, Water quality records," 1970 through 1973 water years.  In addition to the 10 original sites, data were collected during this period from the Umpqua River near Elkton station, and a summary of the data for that station is included in table 1.

  14. Recent sedimentation patterns within the central Atchafalaya Basin, Louisiana

    USGS Publications Warehouse

    Hupp, C.R.; Demas, C.R.; Kroes, D.E.; Day, R.H.; Doyle, T.W.

    2008-01-01

    Sediment deposition and storage are important functions of forested bottomlands, yet documentation and interpretation of sedimentation processes in these systems remain incomplete. Our study was located in the central Atchafalaya Basin, Louisiana, a distributary of the Mississippi River and contains the largest contiguously forested riparian wetland in North America, which suffers from high sedimentation in some areas and hypoxia in others. We established 20 floodplain transects reflecting the distribution of depositional environments within the central Basin and monitored general and local sediment deposition patterns over a three-year period (2000-2003). Deposition rate, sediment texture, bulk density, and loss on ignition (LOI, percent organic material) were determined near or just above artificial markers (clay pads) located at each station per transect. Transect mean sedimentation rates ranged from about 2 to 42 mm/yr, mean percent organic material ranged from about 7% to 28%, mean percent sand (> 63 ??) ranged from about 5% to 44%, and bulk density varied from about 0.4 to 1.3. The sites were categorized into five statistically different clusters based on sedimentation rate; most of these could be characterized by a suite of parameters that included hydroperiod, source(s) of sediment-laden water, hydraulic connectivity, flow stagnation, and local geomorphic setting along transect (levee versus backswamp), which lead to distinct spatial sedimentation patterns. Sites with low elevation (long hydroperiod), high hydraulic connectivity to multiple sources of sediment-laden water, and hydraulic damming (flow stagnation) featured the highest amounts of sediment trapping; the converse in any of these factors typically diminished sediment trapping. Based on aerial extent of clusters, the study area potentially traps 6,720,000 Mg of sediment annually, of which, 820,000 Mg represent organic materials. Thus, the Atchafalaya Basin plays a substantial role in lowland

  15. Sedimentation, accretion, and subsidence in marshes of Barataria Basin, Louisiana

    SciTech Connect

    Hatton, R.S.; DeLaune, R.D.; Patrick, W.H. Jr.

    1983-05-01

    Vertical accretion and sediment accumulation rates were determined from the distribution of /sup 137/Cs in cores collected from fresh water, intermediate, brackish, and salt marshes in the Barataria Basin, Louisiana. Vertical accretion rates vary from about 1.3 cm.yr/sup -1/ in levee areas to 0.7 in backmarshes. Mineral sediment content of the marsh soil profile decreased with distance from the coast. Except in natural levee areas, marsh accretion rates are less than subsidence measured by water level data, however this alone cannot account for observed land-loss patterns in the basin area.

  16. The continental sediments of the Nigerian Coastal Basins

    NASA Astrophysics Data System (ADS)

    Adediran, S. A.; Adegoke, O. S.; Oshin, I. O.

    The development of the coastal basins of Nigeria is examined in terms of a four-stage evolutionary model, viz: intracratonic, synrift, transitional and oceanic. The continental sediments range in age from early Cretaceous to Recent. The oldest sediments in the Western Dahomey Basin (Ise Formation) consist of a predrift sequence of basal conglomerates and loose sands interbedded with clays. Sedimentation in the eastern basins commenced later during the Albian times with the deposition of coarse grained, poorly sorted sands (Mamfe and Awi Formations) of fluviatile origin. These are overlain in all basins by transitional to marine strata. Continental sedimentation resumed in the Maastricthian with the deposition of coarse grained, poorly sorted, sometimes ferruginuous sands and clays (Owelli and Ajali Sandstones). Regression began during the Eocene resulting in the deposition of fine to coarse grained, poorly sorted sands with mudstones (Ilaro Formation) in the west, overlain by crossbedded sandstones with lignites and carbonaceous mudstone (Ogwashi-Asaba Formation). Miocene to Recent limonitic, coarse grained, subangular to well-rounded Benin Sands cap all the basins.

  17. Predominant floodplain over mountain weathering of Himalayan sediments (Ganga basin)

    NASA Astrophysics Data System (ADS)

    Lupker, Maarten; France-Lanord, Christian; Galy, Valier; Lavé, Jérôme; Gaillardet, Jérôme; Gajurel, Ananta Prasad; Guilmette, Caroline; Rahman, Mustafizur; Singh, Sunil Kumar; Sinha, Rajiv

    2012-05-01

    We present an extensive river sediment dataset covering the Ganga basin from the Himalayan front downstream to the Ganga mainstream in Bangladesh. These sediments were mainly collected over several monsoon seasons and include depth profiles of suspended particles in the river water column. Mineral sorting is the first order control on the chemical composition of river sediments. Taking into account this variability we show that sediments become significantly depleted in mobile elements during their transit through the floodplain. By comparing sediments sampled at the Himalayan front with sediments from the Ganga mainstream in Bangladesh it is possible to budget weathering in the floodplain. Assuming a steady state weathering regime in the floodplain, the weathering of Himalayan sediments in the Gangetic floodplain releases ca. (189 ± 92) × 109 and (69 ± 22) × 109 mol/yr of carbonate bound Ca and Mg to the dissolved load, respectively. Silicate weathering releases (53 ± 18) × 109 and (42 ± 13) × 109 mol/yr of Na and K while the release of silicate Mg and Ca is substantially lower, between ca. 0 and 20 × 109 mol/yr. Additionally, we show that sediment hydration, [H2O+], is a sensitive tracer of silicate weathering that can be used in continental detrital environments, such as the Ganga basin. Both [H2O+] content and the D/H isotopic composition of sediments increases during floodplain transfer in response to mineral hydrolysis and neoformations associated to weathering reactions. By comparing the chemical composition of river sediments across the floodplain with the composition of the eroded Himalayan source rocks, we suggest that the floodplain is the dominant location of silicate weathering for Na, K and [H2O+]. Overall this work emphasizes the role of the Gangetic floodplain in weathering Himalayan sediments. It also demonstrates how detrital sediments can be used as weathering tracers if mineralogical and chemical sorting effects are properly taken into

  18. Basin sedimentation and the growth of prograding deltas

    NASA Astrophysics Data System (ADS)

    Syvitski, James P. M.; Smith, John N.; Calabrese, E. A.; Boudreau, B. P.

    1988-06-01

    A theoretical model is developed for the infilling of a basin by the progradation of a delta. The model simulates four mechanisms for the transfer of sediment from the land to the sea: (1) bed load dumping along the delta front, (2) hemipelagic sedimentation under the seaward flowing river plume, (3) proximal slope bypassing by turbidity currents, and (4) the combined effects of both short-term (wave and tidal action) and long-term (creep and small slides) downslope diffusion of the accreting sediment mass. The general model is of relatively low precision, useful for predicting basin infilling on time scales greater than a few hundred years. The river plume portion of the model can predict sedimentation on time scales of less than a year and is designed to reflect the dynamics of a free, two-dimensional, buoyant jet that transports a composite size population of suspended particles. The general model allows the prediction of lithologies changing with time and space. The model has been used to simulate infilling processes for Knight and Bute inlets, two grabenlike (fjord) basins along the coast of British Columbia. Model simulations of delta progradation over the last 10,000 years favorably predicted the modern seafloor bathymetry and sediment accumulation rates to within a factor of 2 of measured (210Pb, 137Cs, and sediment trap) rates.

  19. 1. OVERALL VIEW OF FLOCCULATION/SEDIMENTATION BASINS (#1778), LOOKING NORTHWEST ...

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

    1. OVERALL VIEW OF FLOCCULATION/SEDIMENTATION BASINS (#1778), LOOKING NORTHWEST - Presidio Water Treatment Plant, Flocculation-Sedimentation Basins, East of Lobos Creek at Baker Beach, San Francisco, San Francisco County, CA

  20. 2. DETAIL VIEW OF FLOCCULATION/SEDIMENTATION BASINS (#1778), LOOKING SOUTHWEST ...

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

    2. DETAIL VIEW OF FLOCCULATION/SEDIMENTATION BASINS (#1778), LOOKING SOUTHWEST - Presidio Water Treatment Plant, Flocculation-Sedimentation Basins, East of Lobos Creek at Baker Beach, San Francisco, San Francisco County, CA

  1. Sediment quality in the north coastal basin of Massachusetts, 2003

    USGS Publications Warehouse

    Breault, Robert F.; Ashman, Mary S.; Heath, Douglas

    2004-01-01

    The U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, completed a reconnaissance-level study of bottom-sediment quality in selected lakes, rivers, and estuaries in the North Coastal Basin of Massachusetts. Bottom-sediment grab samples were collected from 20 sites in the North River, Lake Quannapowitt, Saugus River, Mill River, Shute Brook, Sea Plane Basin, Pines River, and Bear Creek. The samples were tested for various types of potentially harmful contaminants? including 33 elements, 17 polyaromatic hydrocarbons (PAHs), 22 organochlorine pesticides, and 7 polychlorinated biphenyl (PCB) mixtures (Aroclors)?to benthic organisms (bottom-dwelling) and humans. The results were compared among sampling sites, to background concentrations, and to concen-trations measured in other urban rivers, and sediment-quality guidelines were used to predict toxicity at the sampling sites to benthic organisms and humans. Because there are no standards for human toxicity for aquatic sediment, standards for contaminated upland soil were used. Contaminant concentrations measured in sediment collected from the North Coastal Basin generally were equal to or greater than concentrations in sediment from uncontaminated rivers throughout New England. Contaminants in North Coastal Basin sediment with elevated concentrations (above back-ground levels) included arsenic, chromium, copper, lead, nickel, and zinc, some of the PAHs, dichlorodiphenyltrichloro-ethane (DDT) and its metabolites, and dieldrin. No PCBs were measured above the detection limits. Measured concentrations of arsenic, chromium, and lead were also generally greater than those measured in other urban rivers throughout the conter-minous United States. With one exception (arsenic), local con-centrations measured in sediment samples collected from the North Coastal Basin were lower than concentrations measured in sediment collected from two of three urban rivers draining to Boston

  2. Contaminants in suspended sediment from the Fraser River basin

    SciTech Connect

    Sekela, M.; Baldazzi, C.; Moyle, G.; Brewer, R.

    1995-12-31

    The concentrations of trace organic contaminants were measured in suspended sediment samples collected upstream and downstream of six pulp mills located in the Fraser River basin. Sampling occurred at three hydrological periods; fall low flow, winter base flow (under ice) and spring freshet. Suspended sediments were analyzed for dioxins, furans, chlorinated phenolics and polycyclic aromatic hydrocarbons. Initial results indicate that (i) trace organic contaminants are detectable in suspended sediments collected over 265 river kilometers downstream of the nearest pulp mill; (ii) the 1992 to 1994 levels of 2,3,7,8-TCD-dioxin and 2,3,7,8-TCD-furan in Fraser river suspended sediments are lower than the levels measured in 1990; (iii) there is a measurable increase in trace organic contaminant levels in Fraser River suspended sediments associated with the initial rise in the Fraser River hydrograph at freshet.

  3. Evaluation of sediment yield and sediment data-collection network in the Piceance basin, northwestern Colorado

    USGS Publications Warehouse

    Kircher, J.E.; Von Guerard, Paul

    1982-01-01

    Statistical relationships were developed between suspended-sediment discharge and several regional factors of climate, physiography, and land use in the Piceance basin, northwestern Colorado. The purpose of the study was to evaluate the existing sediment collection network, especially in regard to detecting changes in suspended-sediment discharge due to the development in the basin. Spatial- and time variability were examined using multiple linear regression techniques. Because of the short period of record, monthly mean sediment loads were used to determine shifts or changes in trends due to mining and related activities in the basin. Dummy variable analysis was used to detect these premining and postmining differences in the regression lines and also to detect seasonal differences in the sediment discharge. Differences did exist in the sediment discharge from season to season and before and after mining; however, due to the variability and short period of record the cause of these differences could not be adequately determined. Part of the high variability in sediment discharge was due to variability in the water discharge. Therefore, if the network is to be improved, the emphasis needs to be on improvement of the water-discharge. The results of the monthly mean regression analysis were used in the mean monthly and mean annual analysis for determination of initial network design equations. These were only preliminary in nature and could be improved with additional data. (USGS)

  4. Influence of basin connectivity on sediment source, transport, and storage within the Mkabela Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Miller, J. R.; Mackin, G.; Lechler, P.; Lord, M.; Lorentz, S.

    2012-09-01

    The management of sediment and other non-point source (NPS) pollution has proven difficult, and requires a sound understanding of particle movement through the drainage system. The primary objective of this investigation was to obtain an understanding of NPS sediment source(s), transport, and storage within the Mkabela basin, a representative agricultural catchment within the KwaZulu-Natal Midlands of southeastern South Africa, by combining geomorphic, hydrologic and geochemical fingerprinting analyses. The Mkabela Basin can be subdivided into three distinct subcatchments that differ in their ability to transport and store sediment along the axial valley. Headwater (upper catchment) areas are characterized by extensive wetlands that act as significant sediment sinks. Mid-catchment areas, characterized by higher relief and valley gradients, exhibit few wetlands, but rather are dominated by a combination of alluvial and bedrock channels that are conducive to sediment transport. The lower catchment exhibits a low-gradient alluvial channel that is boarded by extensive riparian wetlands that accumulate large quantities of sediment (and NPS pollutants). Fingerprinting studies suggest that silt- and clay-rich layers found within wetland and reservoir deposits are derived from the erosion of fine-grained, valley bottom soils frequently utilized as vegetable fields. Coarser-grained deposits within both wetlands and reservoirs result from the erosion of sandier hillslope soils extensively utilized for sugar cane, during relatively high magnitude runoff events that are capable of transporting sand-sized sediment off the slopes. Thus, the source of sediment to the axial valley varies as a function of sediment size and runoff magnitude. Sediment export from the basin was limited until the early 1990s, in part because the upper catchment wetlands were hydrologically disconnected from lower parts of the watershed during low- to moderate flood events. The construction of a

  5. Influence of basin connectivity on sediment source, transport, and storage within the Mkabela Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Miller, J. R.; Mackin, G.; Lechler, P.; Lord, M.; Lorentz, S.

    2013-02-01

    The management of sediment and other non-point source (NPS) pollution has proven difficult, and requires a sound understanding of particle movement through the drainage system. The primary objective of this investigation was to obtain an understanding of NPS sediment source(s), transport, and storage within the Mkabela Basin, a representative agricultural catchment within the KwaZulu-Natal Midlands of eastern South Africa, by combining geomorphic, hydrologic and geochemical fingerprinting analyses. The Mkabela Basin can be subdivided into three distinct subcatchments that differ in their ability to transport and store sediment along the axial valley. Headwater (upper catchment) areas are characterized by extensive wetlands that act as significant sediment sinks. Mid-catchment areas, characterized by higher relief and valley gradients, exhibit few wetlands, but rather are dominated by a combination of alluvial and bedrock channels that are conducive to sediment transport. The lower catchment exhibits a low-gradient alluvial channel that is boarded by extensive riparian wetlands that accumulate large quantities of sediment (and NPS pollutants). Fingerprinting studies suggest that silt- and clay-rich layers found within wetland and reservoir deposits of the upper and upper-mid subcatchments are derived from the erosion of fine-grained, valley bottom soils frequently utilized as vegetable fields. Coarser-grained deposits within these wetlands and reservoirs result from the erosion of sandier hillslope soils extensively utilized for sugar cane, during relatively high magnitude runoff events that are capable of transporting sand-sized sediment off the slopes. Thus, the source of sediment to the axial valley varies as a function of sediment size and runoff magnitude. Sediment export from upper to lower catchment areas was limited until the early 1990s, in part because the upper catchment wetlands were hydrologically disconnected from lower parts of the watershed during

  6. Cenozoic North American Drainage Basin Evolution, Sediment Yield, and Accumulation in the Gulf of Mexico Basin

    NASA Astrophysics Data System (ADS)

    Galloway, W.; Ganey-Curry, P. E.

    2010-12-01

    The Cenozoic fill of the Gulf of Mexico basin contains a continuous record of sediment supply from the North American continental interior for the past 65 million years. Regional mapping of unit thickness and paleogeography for 18 depositional episodes defines patterns of shifting entry points of continental fluvial systems and quantifies the total volume of sediment supplied during each episode. Eight fluvio-deltaic depocenters, named for geographic similarities to entry points and drainage basins of modern rivers, are present. From southwest to northeast, they are the Rio Bravo, Rio Grande, Guadalupe, Colorado, Houston-Brazos, Red, Mississippi, and Tennessee axes. Sediment volume was calculated from hand-contoured unit thickness maps compiled from basin-wide well and seismic control. Using a GIS algorithm to sum volumes within polygons bounding interpreted North American river contribution, the total extant volume was then calculated. General compaction factors were used to convert modern volume to quantitative approximations of total grain volume. Grain volume rate of supply for each depositional episode was then calculated. Values vary by more than an order of magnitude. Supply rate has commonly varied by two-fold or more between successive depositional episodes. Sediment supply is a significant, independent variable in development of stratigraphic sequences within the Gulf basin. Paleogeographic maps of the continental interior for eleven Cenozoic time intervals display the evolving and complex interplay of intracontinental tectonism, climate change, and drainage basin evolution. Five tectono-climatic eras are differentiated: Paleocene late Laramide era; early to middle Eocene terminal Laramide era; middle Cenozoic (Late Eocene—Early Miocene) dry, volcanogenic era; middle Neogene (Middle—Late Miocene) arid, extensional era; and late Neogene (Plio—Pleistocene) monsoonal, epeirogenic uplift era. Sediment supply to the GOM reflects the interplay of (1

  7. Toxicity assessment of sediments from three European river basins using a sediment contact test battery.

    PubMed

    Tuikka, A I; Schmitt, C; Höss, S; Bandow, N; von der Ohe, P C; de Zwart, D; de Deckere, E; Streck, G; Mothes, S; van Hattum, B; Kocan, A; Brix, R; Brack, W; Barceló, D; Sormunen, A J; Kukkonen, J V K

    2011-01-01

    The toxicity of four polluted sediments and their corresponding reference sediments from three European river basins were investigated using a battery of six sediment contact tests representing three different trophic levels. The tests included were chronic tests with the oligochaete Lumbriculus variegatus, the nematode Caenorhabditis elegans and the mudsnail Potamopyrgus antipodarum, a sub-chronic test with the midge Chironomus riparius, an early life stage test with the zebra fish Danio rerio, and an acute test with the luminescent bacterium Vibrio fischeri. The endpoints, namely survival, growth, reproduction, embryo development and light inhibition, differed between tests. The measured effects were compared to sediment contamination translated into toxic units (TU) on the basis of acute toxicity to Daphnia magna and Pimephales promelas, and multi-substance Potentially Affected Fractions of species (msPAF) as an estimate for expected community effects. The test battery could clearly detect toxicity of the polluted sediments with test-specific responses to the different sediments. The msPAF and TU-based toxicity estimations confirmed the results of the biotests by predicting a higher toxic risk for the polluted sediments compared to the corresponding reference sediments, but partly having a different emphasis from the biotests. The results demonstrate differences in the sensitivities of species and emphasize the need for data on multiple species, when estimating the effects of sediment pollution on the benthic community.

  8. Modelling depositional shifts between sedimentary basins: Sediment pathways in Paratethys basins during the Messinian Salinity Crisis

    NASA Astrophysics Data System (ADS)

    Bartol, J.; Matenco, L.; Garcia-Castellanos, D.; Leever, K.

    2012-04-01

    The evolution of sedimentary basins separated by uplifted topographic barriers is characterised by gradual regressive deposition until one of the basins is filled and its sedimentation bypasses to the adjacent basin, defining a depositional shift. One of the critical parameters controlling these depositional shifts is sea level variation, its drop potentially triggering a depositional shift by cancelling the available accommodation space. Conversely, a sea level rise can create new accommodation space resulting in a depositional shift towards a previously overfilled basin. Here we use a three dimensional numerical model to study the sedimentary response to sea level variations of a system of two basins. In this model, a single mountainous source area is feeding an intra-continental basin that is separated by a submarine barrier from another basin with normal marine bathymetry. The sedimentary response is modelled during a cycle of sea-level drop and subsequent rebound that exposes the barrier to sub-aerial erosion. The examined parameters are the barrier height, magnitude and duration of sea level change, climate and flexural rigidity. Modelling demonstrates that shifting the bulk of sedimentation from the continental basin to the open marine environment requires some minimum magnitudes and durations of sea level drop. Moreover, given the specific geometry and parameters of our model, an intervening barrier causes a delay of up to 0.35 Myr, depending on the magnitude and duration of sea level change, to the onset of an outward depositional shift when compared to a situation without a barrier. These depositional shifts depend on changes in climate, magnitude and duration of sea level change. Model results are applied to the connectivity between the Black Sea and the Dacic Basin, suggesting that depositional shifts observed during the Messinian Salinity Crisis can be explained by a sea level drop of > 1000 m in the Black Sea.

  9. Hydrology and sedimentation of Bixler Run Basin, central Pennsylvania

    USGS Publications Warehouse

    Reed, Lloyd A.

    1976-01-01

    Rainfall, streamflow, stream chemical, and sediment discharge data were collected from Bixler Run near Loysville, Pa., during the period from February 1954 to September 1969 as part of a project to evaluate sediment discharge from an agricultural area in which soil-conservation techniques were being adopted at a moderate rate. The study was conducted by the U.S. Geological Survey in cooperation with the Pennsylvania Department of Environmental Resources, State Conservation Commission. Sediment yields from the basin averaged 64 tons per square mile (22 tonnes per square kilometre) per year, approximately 25 percent less than yields from the surrounding area. The relation between water discharge and suspended-sediment discharge remained constant during the study. Suspended-sediment concentrations in the streamflow were less than 10 milligrams per litre 70 percent of the time. The concentration of chloride ions in the streamflow increased from 1959 to 1969. Ground water maintained flows at the gaging location at a rate of 1.9 cubic feet per second (0.054 cubic metres per second) during the period of data collection.

  10. Anastomosed river deposits, sedimentation rates, basin subsidence and locations in proximal molasse basins

    SciTech Connect

    Smith, D.G.

    1984-07-01

    Recent research on large sized modern anastomosing river systems (upper Columbia River, British Columbia, Canada, and Magdalena River, Colombia, South America) has recognized six depositional environments: channel, levee, crevasse-splay, lacustrine, marsh, and peat bog or swamp. Average sedimentation rates in both river systems are 5 mm/yr and 3.8 mm/yr, respectively. Such rapid sedimentation rates (vertical accretion) are keeping pace with equivalent rates of basin subsidence. High rates of sedimentation and basin subsidence are most likely to be found at proximal locations in molasse basins during major orogenic pulses. Such conditions were present during the Columbian and Laramide orogenies during the early Cretaceous and Tertiary in the foreland adjacent to the Rocky Mountain system. Thus, channel and crevasse-splay shale-encased sandstone reservoirs and coal, common in anastomosed fluvial rock sequences in proximal molasse settings, should be encountered in parts of the Western Interior sedimentary basin. Such deposits probably have been interpreted as deltaic or alluvial plain and should be reexamined to better predict sandstone trends for hydrocarbon exploration.

  11. Cosmogenic nuclide-derived sediment budget of the Amazon basin

    NASA Astrophysics Data System (ADS)

    Wittmann, Dr.; von Blanckenburg, Dr.; Guyot, Dr.; Maurice, Dr.; Kubik, Dr.

    2009-04-01

    Sediment gauging suggests that the annual sediment mass discharged into the main Amazon basin from the Andes and the cratonic shields is not in steady state with the mass discharged to the Atlantic Ocean. Here we use sediment production rates from cosmogenic 10Be in sediment to compare these with transport rates from river load gauging. About 1 million km2 or 95% of the total Andean area draining to the Amazon provide sediment to the central Amazon river with an averaged 10Be nuclide concentration of 5.0 +- 0.5x1e4 at/g(Qz). Average nuclide concentrations for Brazilian shield headwaters amount to 15.3 +- 1.2x1e4 at/g(Qz), and to 38.6 +- 2.4x1e4 at/g(Qz) for the Guyana shield headwaters, respectively. For the Andes, nuclide concentrations translate to an integrated Andean denudation rate of 0.35 ± 0.05 mm/yr. Sediment from the headwaters of the Brazilian and Guyana shields translate into very low denudation rates (0.02 and 0.01 mm/yr, respectively), as is expected for tectonically stable tropical highlands. These headwater 10Be nuclide concentrations and derived denudation rates can now be compared with those derived from central Amazon stream sediment including the main Amazon, which was sampled over ~1000 km from Manaus to Óbidos. Cosmogenic nuclide concentration analyses of several grain sizes (from 125 up to 800 µm) show large variations; we found that coarse-grained material records the nuclide signal of the cratonic shield areas, whereas the Andean signal is best represented by the fine sand fraction, which is preserved virtually unaltered over 1000s of km of sediment transport. In all central Amazon trunk stream samples and tributaries, the fine grain size fraction (125-250 µm) contains 10Be at 6.5 +- 1.2x1e4 at/g(Qz), which is similar to that of the Andean source areas. The integrated denudation rate from this fraction is 0.23 +- 0.04 mm/yr for the entire Amazon basin at Óbidos, which compares well with the mean Andean denudation rate of 0.35 +- 0.05 mm

  12. Stream sediment detailed geochemical survey for Date Creek Basin, Arizona

    SciTech Connect

    Butz, T.R.; Tieman, D.J.; Grimes, J.G.; Bard, C.S.; Helgerson, R.N.; Pritz, P.M.

    1980-06-30

    Results of the Date Creek Basin detailed geochemical survey are reported. Field and laboratory data are reported for 239 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are displayed. A generalized geologic map of the area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. Based on stream sediment geochemical data, significant concentrations of uranium are restricted to the Anderson Mine area. The 84th percentile concentrations of U-FL, U-NT, and U-FL/U-NT combined with low thorium/U-NT values reflect increased mobility and enrichment of uranium in the carbonate host rocks of that area. Elements characteristically associated with the uranium mineralization include lithium and arsenic. No well defined diffusion halos suggesting outliers of similar uranium mineralization were observed from the stream sediment data in other areas of the Date Creek Basin. Significant concentrations of U-FL or U-NT found outside the mine area are generally coincident with low U-FL/U-NT values and high concentrations of zirconium, titanium, and phosphorus. This suggests that the uranium is related to a resistate mineral assemblage derived from surrounding crystalline igneous and metamorphic rocks.

  13. Transient electromagnetic study of basin fill sediments in the Upper San Pedro Basin, Mexico

    USGS Publications Warehouse

    Bultman, M.W.; Gray, F.

    2011-01-01

    The Upper San Pedro River Basin in Mexico and the United States is an important riparian corridor that is coming under increasing pressure from growing populations and the associated increase in groundwater withdrawal. Several studies have produced three-dimensional maps of the basin fill sediments in the US portion of the basin but little work has been done in the Mexican portion of the basin. Here, the results of a ground-based transient electromagnetic (TEM) survey in the Upper San Pedro Basin, Mexico are presented. These basin fill sediments are characterized by a 10-40 m deep unsaturated surficial zone which is composed primarily of sands and gravels. In the central portion of the basin this unsaturated zone is usually underlain by a shallow clay layer 20-50 m thick. Beneath this may be more clay, as is usually the case near the San Pedro River, or interbedded sand, silt, and clay to a depth of 200-250 m. As you move away from the river, the upper clay layer disappears and the amount of sand in the sediments increases. At 1-2 km away from the river, sands can occupy up to 50% of the upper 200-250 m of the sediment fill. Below this, clays are always present except where bedrock highs are observed. This lower clay layer begins at a depth of about 200 m in the central portion of the basin (250 m or more at distances greater than 1-2 km from the river) and extends to the bottom of most profiles to depths of 400 m. While the depth of the top of this lower clay layer is probably accurate, its thickness observed in the models may be overestimated due to the relatively low magnetic moment of the TEM system used in this study. The inversion routine used for interpretation is based on a one-dimensional geologic model. This is a layer based model that is isotropic in both the x and y directions. Several survey soundings did not meet this requirement which invalidates the inversion process and the resulting interpretation at these locations. The results from these

  14. Episodic Emplacement of Sediment + Carbon within Large Tropical River Basins

    NASA Astrophysics Data System (ADS)

    Aalto, R.; Aufdenkampe, A.

    2012-04-01

    Application of advanced methods for imaging (sub-bottom sonar and ERGI), dating (high resolution 210-Pb and 14-C from deep cores), and biogeochemical analysis have facilitated the characterization and inter-comparison of floodplain sedimentation rates, styles, and carbon loading across disparate large river basins. Two examples explored here are the near-pristine 72,000 km2 Beni River basin in northern Bolivia and the similarly natural 36,000 km2 Strickland River basin in Papua New Guinea - that are located on either side of the Equatorial Pacific warm pool that drives the ENSO phenomenon. Our published research suggests that large, rapid-rise, cold-phase ENSO floods account for the preponderance of sediment accumulation within these two tropical systems. New results to be presented at EGU further clarify the extent of modern deposits (~100 yrs) within both systems and add a deeper perspective into how these extensive floodplains developed over the Holocene, both in response to external forcing (climate and base level) and internal system morphodynamics. The vast scale of these temporally discrete deposits (typically 100s of millions of tonnes over relatively short time periods) involved equate to high burial rates, which in turn support the high carbon loadings sequestered within the resulting sedimentary deposits. We have identified the principal source of this carbon and sedimentary material to be extensive landslides throughout the high-relief headwaters - failures that deliver huge charges of pulverized rock and soil directly into canyons (in both the Bolivian Andes and the PNG Highlands), where raging floodwaters provide efficient transport to lowland depocentres. We present recent results from our research in these basins, providing insight into the details of such enormous mass budgets that result in a signicant carbon sink within the floodplains. Processes, timing, and rates are compared between the two systems, providing insight into the nature of

  15. Flooding and sedimentation in Wheeling Creek basin, Belmont County, Ohio

    USGS Publications Warehouse

    Kolva, J.R.; Koltun, G.F.

    1987-01-01

    The Wheeling Creek basin, which is located primarily in Belmont County, Ohio, experienced three damaging floods and four less severe floods during the 29-month period from February 1979 through June 1981. Residents of the basin became concerned about factors that could have affected the severity and frequency of out-of-bank floods. In response to those concerns, the U.S. Geological Survey, in cooperation with the Ohio Department of Natural Resources, undertook a study to estimate peak discharges and recurrence intervals for the seven floods of interest, provide information on current and historical mining-related stream-channel fill or scour, and examine storm-period subbasin contributions to the sediment load in Wheeling Creek. Streamflow data for adjacent basins, rainfall data, and, in two cases, flood-profile data were used in conjunction with streamflow data subsequently collected on Wheeling Creek to provide estimates of peak discharge for the seven floods that occurred from February 1979 through June 1981. Estimates of recurrence intervals were assigned to the Peak discharges on the basin of regional regression equations that relate selected basin characteristics to peak discharge with fixed recurrence intervals. These estimates indicate that a statistically unusual number of floods with recurrence intervals of 2 years or more occurred within that time period. Three cross sections located on Wheeling Creek and four located on tributaries were established and surveyed quarterly for approximately 2 years. No evidence of appreciable stream-channel fill or scour was observed at any of the cross sections, although minor profile changes were apparent at some locations. Attempts were made to obtain historical cross-section profile data for comparison with current cross-section profiles; however, no usable data were found. Excavations of stream-bottom materials were made near the three main-stem cross-section locations and near the mouth of Jug Run. The bottom

  16. Paleotectonic controls on sedimentation in northern Williston basin area, Saskatchewan

    SciTech Connect

    Kent, D.M.

    1983-08-01

    The Williston basin lies within the so-called stable cratonic interior and would not be expected to have had the same intensity of tectonic activity as is generally considered to be characteristic of cratonic margin sedimentary basins. From time to time, however, other structural features appear to have been effective controls on sediment distribution patterns. In southern Saskatchewan, one of the most active of these was the Swift current platform. This feature appears to have been sufficiently positive during early Paleozoic time to have caused a distinct thinning of those sediments over it. The platform was mildly positive during other periods of sedimentation, as well as during periods of erosion. It was a site of widespread salt solution during Mesozoic time, which was also its time of major tectonic fluctuation, as well as being the period when it had the most significant influence on sedimentation. Southeastern Saskatchewan is the locale for some significant regional gravity and magnetic anomalies which appear related to exposed structural zones in the Precambrian Shield. A major gravity anomaly on the extreme eastern side of the province is on trend with the Nelson River zone of Manitoba and a magnetic anomaly (Camfield-Gough conductor zone) can be traced to the Wollaston trend in north-central Saskatchewan. The Camfield-Gough zone is particularly significant in that it lies along the axis of the Hummingbird trough, an area affected by basement-controlled early salt solution, and it extends southward into the United States, where it is flanked by a number of local multizone oil-producing structures in North Dakota and Montana.

  17. Arsenic incorporation into authigenic pyrite, Bengal Basin sediment, Bangladesh

    USGS Publications Warehouse

    Lowers, H.A.; Breit, G.N.; Foster, A.L.; Whitney, J.; Yount, J.; Uddin, Md. N.; Muneem, Ad. A.

    2007-01-01

    Sediment from two deep boreholes (???400 m) approximately 90 km apart in southern Bangladesh was analyzed by X-ray absorption spectroscopy (XAS), total chemical analyses, chemical extractions, and electron probe microanalysis to establish the importance of authigenic pyrite as a sink for arsenic in the Bengal Basin. Authigenic framboidal and massive pyrite (median values 1500 and 3200 ppm As, respectively), is the principal arsenic residence in sediment from both boreholes. Although pyrite is dominant, ferric oxyhydroxides and secondary iron phases contain a large fraction of the sediment-bound arsenic between approximately 20 and 100 m, which is the depth range of wells containing the greatest amount of dissolved arsenic. The lack of pyrite in this interval is attributed to rapid sediment deposition and a low sulfur flux from riverine and atmospheric sources. The ability of deeper aquifers (>150 m) to produce ground water with low dissolved arsenic in southern Bangladesh reflects adequate sulfur supplies and sufficient time to redistribute the arsenic into pyrite during diagenesis.

  18. Polyphase basin evolution of the Vienna Basin inferred from 3D visualization of sedimentation setting and quantitative subsidence

    NASA Astrophysics Data System (ADS)

    Lee, Eun Young; Novotny, Johannes; Wagreich, Michael

    2016-04-01

    This study analyzed and visualized data from 210 wells using a MATLAB-based program (BasinVis 1.0) for 3D visualization of sediment distribution, thickness, and quantitative subsidence of the northern and central Vienna Basin. The sedimentation settings for selected horizons were visualized to 3D sediment distribution maps, isopach maps, and cross-sections. Subsidence of the study area resulted in 3D subsidence depth and rate maps of basement and tectonic subsidences. Due to the special position of the Vienna Basin, the basin evolution was influenced by the regional tectonics of surrounding units. The 2D/3D maps provided insights into the polyphase evolution of the Vienna Basin, which is closely related to changes in the changing regional stress field and the paleoenvironmental setting. In the Early Miocene, the sedimentation and subsidence were shallow and E-W/NE-SW trending, indicating the development of piggy-back basins. During the late Early Miocene, maps show wider sedimentation and abruptly increasing subsidence by sinistral strike-slip faults, which initiated the Vienna pull-apart basin system. The sediments of the Early Miocene were supplied through a small deltaic system entering from the south. After thin sedimentation and shallow subsidence of the early Middle Miocene, the development of the Vienna Basin was controlled and accelerated mainly by NE-SW trending synsedimentary normal faults, especially the Steinberg fault. From the Middle Miocene, the subsidence was decreasing overall, however the tectonic subsidence show regionally different patterns. This study suggests that a major tensional regime change, from transtension to E-W extension, caused laterally varying subsidence across the Vienna Basin. The Late Miocene was characterized by the slowing down of basement and tectonic subsidence. From the middle Middle to Late Miocene, enormous amount of sediments supplied by a broad paleo-Danube delta complex on the western flank of the basin. The latest

  19. Campano-Maastrichtian foraminifera from onshore sediments in the Rio del Rey Basin, Southwest Cameroon

    NASA Astrophysics Data System (ADS)

    Njoh, Oliver Anoh; Victor, Obiosio; Christopher, Agyingi

    2013-03-01

    Campanian-Maastrichtian marine sediments outcrop in five genetically linked sedimentary basins along the West African coast in the Gulf of Guinea, from the Douala Basin in Cameroon to the Anambra Basin in Nigeria. These sediments in the more centrally located Rio del Rey Basin have been the least studied. Therefore, the geologic history of this region has merely been speculative. The Rio del Rey Basin like the adjacent Niger Delta is producing hydrocarbon from the offshore Tertiary sedimentary interval in which all studies have been focused, neglecting the onshore Cretaceous sediments. Outcrops in the basin are rare, small and highly weathered. Samples from some of these sediments have yielded a few Planktonic and dominantly benthonic foraminiferal assemblages. The long-ranging heterohelix and hedbergellids characterized the planktics while the species Afrobolivina afra which is a well known diagnostic taxon for Campanian-Maastrichtian sediments in West African basins clearly dominate the benthic assemblage. Its occurrence in association with other Upper Cretaceous forms such as Bolivina explicata, Praebulimina exiqua, Gabonita lata, Ammobaculites coprolithiformis amongst others, formed the basis on which this age was assigned to the sediments sampled from the Rio del Rey Basin. Hence, this work has undoubtedly established the much needed link in this regional geologic history and correlates these sediments with the Logbaba and Nkporo Formations in the Douala Basin in Cameroon and the southeastern Nigerian Sedimentary Basins. Thus, these units were all deposited during this same geologic period and probably controlled by the same geologic event.

  20. Trends in chlorinated hydrocarbon levels in Hudson River basin sediments.

    PubMed Central

    Bopp, R F; Chillrud, S N; Shuster, E L; Simpson, H J; Estabrooks, F D

    1998-01-01

    Analysis of sections from dated sediment cores were used to establish geographic distributions and temporal trends of chlorinated hydrocarbon contaminant levels in sediments from natural waters of the Hudson River basin. Radiometric dating was based primarily on the depth distribution of 137(Cs) in the cores and on the occurrence of detectable levels of 7(Be) in surface sediment samples. Eighteen sampling sites included several along the main stem of the Hudson, its major tributaries, and components of the New York/New Jersey (NY/NJ) harbor complex. Drinking-water reservoirs were sampled to place upper limits on atmospheric inputs. Core sections were analyzed for polychlorinated biphenyls (PCBs), 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT)-derived compounds, chlordane, and dioxins. Sediment concentrations of most contaminants at most sites have decreased significantly since the mid-1960s. The data provide a basinwide perspective on major point-source inputs of PCBs to the upper Hudson River and of 2,3,7,8-tetrachlorodibenzo-p-dioxin and DDT to the lower Passaic River. Evidence was found for significant but poorly characterized sources of PCBs and chlordane to the western NY/NJ harbor, and of highly chlorinated dioxins to the upstream sites on the main stem of the Hudson. The results indicate that analysis of dated sediment samples is a most effective and efficient monitoring tool for the study of large-scale geographic and temporal trends in levels of particle-associated contaminants. Images Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:9703496

  1. Assessing the Potential for Managing Sediment in the Mekong River Basin

    NASA Astrophysics Data System (ADS)

    Wild, T. B.; Loucks, D. P.

    2012-12-01

    The Mekong/Lancang River Basin is undergoing a period of rapid hydropower development that will likely result in altering the natural flow and sediment regimes. This could significantly impact the exceptional biodiversity and food production characteristics of the basin's ecosystems. Additionally, alteration of natural sediment processes could impact the geomorphologic makeup of the system, as well as hydropower output and reliability. This study is devoted to exploring the potential for implementing reservoir sediment management practices. Research in collaboration with in-basin hydrologic institutions in Vietnam, Laos and Cambodia has focused on a subset of reservoirs that will trap significant quantities of sediment, and that if properly located, designed and operated, could allow sediment passage. Simulation results are presented for reservoirs at several locations throughout the basin, including reservoirs in the Sre Pok, Se San and Se Kong sub-basins (called the "3S" basins), which are a particularly important set of adjacent, transboundary watersheds with respect to biodiversity and ecological productivity. The 3S basins also serve as an important source of flow and sediment to the mainstream Mekong River. Simulation results permit an evaluation of the improvement (compared to current/expected conditions) in sediment passage through reservoirs that is possible if different reservoir sediment management techniques are implemented, including sediment bypasses, flushing and sluicing. Our sediment simulation model implements a daily time-step mass-balance simulation of flow and sediment to predict in relative terms the spatial and temporal accumulation and depletion of sediment in river reaches and in reservoirs under different sediment management policies. The model results include the relative tradeoffs between hydropower production, sediment regime alteration, and flow regime alteration associated with the sediment management techniques deemed feasible at

  2. Fluvial sediment in the little Arkansas River basin, Kansas

    USGS Publications Warehouse

    Albert, C.D.; Stramel, G.J.

    1966-01-01

    Characteristics and transport of sediment in the Little Arkansas River basin in south-central Kansas were studied to determine if the water from the river could be used as a supplemental source for municipal supply or would provide adequate recharge to aquifers that are sources of municipal and agricultural water supplies. During periods when overland 1low contributed a significant amount to streamflow, the suspended sediment in the Little Arkansas River at Valley Center averaged about 85 percent of clay, about 13 percent of silt, and about 2 percent of sand. The average annual suspended-sediment discharge for the water years 1958, 1959, 1960, and 1961 was about 306,000 tons, and about 80 percent of the load was transported during 133 days of the 1,461-day period. The average daily water discharge of 352 cubic feet per second for the period 1958-61 was more than the long-term (i}9-year) average of 245 cfs; therefore, the average annual sediment load for 1958-61 was probably greater than the average annual load for the same long-term period. Studies of seepage in a part of the channel of Kisiwa Creek indicated that an upstream gravel-pit operation yielded clays which, when deposited in the channel, reduced seepage. A change in plant operation and subsequent runoff that removed the deposited clays restored natural seepage conditions. Experiments by the Wichita Water Department showed that artificial recharge probably cannot be accomplished by using raw turbid water that is injected into wells or by using pits. Recharge by raw turbid water on large permeable areas or by seepage canals may be feasible. Studies of chemical quality of surface water at several sites in the Little Arkansas River basin indicate that Turkey. Creek is a major contributor of chloride and other dissolved solids to the Little Arkansas River and that the dissolved-solids content is probably highest during low-flow periods when suspended-sediment concentration is low. Data collected by the Wichita

  3. Accelerator-mass spectrometer (AMS) radiocarbon dating of Pleistocene lake sediments in the Great Basin

    USGS Publications Warehouse

    Thompson, R.S.; Toolin, L.J.; Forester, R.M.; Spencer, R.J.

    1990-01-01

    Pleistocene lake sediments in the Great Basin typically contain little organic carbon, and thus are difficult to date reliably by conventional radioccarbon methods. Paleoenvironmental data are abundant in these sediments, but are of limited value without adequate age controls. With the advent of accelerator-mass spectrometer (AMS) radiocarbon dating, it is now possible to date these paleolacustrine sediments. AMS dates were obtained on sediment cores from the Bonneville, Franklin, and Lahontan Basins. In the Bonneville Basin, the AMS-based chronology compares well with other chronologies constructed from dated shore-zone features. In the Bonneville and Franklin basins, AMS dates delimit unconformities not apparent by other means. We found that dispersed organic carbon from sediments deposited during relatively freshwater intervals provided apparently reliable AMS radiocarbon dates. Carbonate microfossils from the Lahontan Basin also produced results that appear reasonable, while bulk carbonate yielded erroneous results. ?? 1990.

  4. Sediment supply from the Betic-Rif orogen to basins through Neogene

    NASA Astrophysics Data System (ADS)

    Iribarren, L.; Vergés, J.; Fernàndez, M.

    2009-09-01

    We present a quantification of total and partial (divided by time slices) sedimentary volumes in the Neogene basins of the Betic-Rif orogen. These basins include the Alboran Sea, the intramontane basins, the Guadalquivir and Rharb foreland basins and the Atlantic Margin of the Gibraltar Arc. The total volume of Neogene sediments deposited in these basins is ~ 209,000 km 3 and is equally distributed between the internal (Alboran Basin and intramontane basins) and the external basins (foreland basins and Atlantic Margin). The largest volumes are recorded by the Alboran Basin (89,600 km 3) and the Atlantic Margin (81,600 km 3). The Guadalquivir and Rharb basins amount 14,000 km 3 and 14,550 km 3, respectively whereas the intramontane basins record 9235 km 3. Calculated mean sediment accumulation rates for the early-middle Miocene show an outstanding asymmetry between the Alboran basin (0.24 mm/yr) and the foreland basins (0.06-0.07 mm/yr) and the Atlantic Margin (0.03 mm/yr). During the late Miocene, sedimentation rates range between 0.17 and 0.18 mm/yr recorded in the Alboran Basin and 0.04 mm/yr in the intramontane basins. In the Pliocene-Quaternary, the highest sedimentation rates are recorded in the Atlantic Margin reaching 0.22 mm/yr. Sedimentary contribution shows similar values for the inner and outer basins with a generalized increase from late Miocene to present (from 3500 to 6500 km 3/My). Interestingly, the Alboran Basin records the maximum sedimentary contribution during the late Miocene (5500 km 3/My), whereas the Atlantic Margin does during the Pliocene-Quaternary (6600 km 3/My). The spatial and time variability of the sediment supply from the Betic-Rif orogen to basins is closely related to the morphotectonic evolution of the region. The high sedimentation rates obtained in the Alboran Basin during the early-middle Miocene are related to active extensional tectonics, which produced narrow and deep basins in its western domain. The highest sedimentary

  5. Does the Sediment Flux Balance of the Larsen Basin, Antarctic Peninsula, Record Glacial Sediment Transport during the Cretaceous Greenhouse?

    NASA Astrophysics Data System (ADS)

    Oliver, B.; Barbeau, D. L.; Hemming, S. R.

    2011-12-01

    Recent geochemical, sequence stratigraphic, and integrated investigations of marine strata from several continental margins and ocean basins suggest that ephemeral ice sheets may have existed on Antarctica during parts of the Cretaceous and early Paleogene thought to be too warm for widespread glaciation. The existence of these ice sheets during the Cretaceous, despite a greenhouse global climate driven by atmospheric CO2 levels two to four times the modern concentration, underscores an insufficiency in our understanding of the relationship between climate change, glaciation, and sea level rise that could affect our ability to predict deglaciation and sea level changes as a result of anthropogenic warming. Preliminary mass-balance calculations between the Larsen Basin, a sedimentary basin adjacent to the northernmost Antarctic Peninsula, and the Peninsula itself offer new evidence in support of the Cretaceous glaciation hypothesis. Simple computations based on the thickness and areal extent of the Larsen basin and the average exhumation depths of the proximal Antarctic Peninsula suggest that the sediment eroded from Peninsula can account for less than 60% of Larsen sediments. The large sediment excess requires both a more distal source region and a mechanism to transport a large amount of sediment from that source. Further, new detrital zircon geochronology from the early Paleogene strata of the Larsen basin indicate substantial contributions of sediment from non-Peninsular sources, of which the Ellsworth Mountains provide the closest match in zircon age populations. The presence of sediment derived from the Ellsworths in the distant Larsen Basin implies that ephemeral, but extensive, ice sheets could have been responsible for transporting the sediment to the basin. A time-dependent reconstruction of the source-to-sink sedimentation history of the Larsen Basin-Antarctic Peninsula system will thus be invaluable in evaluating the Cretaceous glaciation hypothesis. A

  6. Characterization of the efficiency of sedimentation basins downstream of harvested peat bogs

    NASA Astrophysics Data System (ADS)

    Samson-Do, Myriam; St-Hilaire, André

    2015-04-01

    Peat harvesting is a very lucrative industry in the provinces of Quebec and New-Brunswick (Canada). Peat enters in many potting mix used for horticulture. However, harvesting this resource has some impacts on the environment. First, industries need to drain the peat bog to dry the superficial layer. Then, it is harvested with industrial vacuums and the underlying layer is allowed to dry. The drained water is laden with suspended sediments (mostly organic peat fibers) that may affect biota of the stream where it is discharged. To counter the problem, this water does not go directly on the stream but first flows through a sedimentation basin, built to reduce suspended sediment loads. This work focuses on characterizing and eventually modeling the efficiency of those sedimentation basins. Seven basins were studied in Rivière-du-Loup, St-Valère and Escoumins (Quebec, Canada). They each have a different ratio basin area/drained area (4.7 10-4 to 20.3 10-4). To continuously monitor the sediment loads (calculated from sediment concentrations and discharge) entering and leaving basins, a nephelometer and a level logger were installed in the water column upstream and downstream of sedimentation basins. Their trapping efficiency was measured during the ice-free period (May to October) and for each significant rain event, since it is known that the rain and subsequent runoff induce most of the peat transport in and out of the basin. Results show that the event efficiency decreases as the basin is filled up with trapped sediments. For one basin, the efficiency was 85August. Trapping efficiency can be used as a tool to estimate basin dimensions. This has been done for municipal sedimentation ponds that trap minerals and will be adapted to the current context, where the dominant sediment is organic.

  7. Characterization of Stream Morphology and Sediment Yield for the Big Black and Tombigbee River Basins, Mississippi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three segments within the Big Black River Basin, and nine within the Tombigbee River Basin are on the Mississippi 303d list of water bodies as having impaired conditions for aquatic life due to sediment. An additional 56 reaches of channel are listed for biologic impairment between the two basins. ...

  8. Provenance and sediment dispersal of the Triassic Yanchang Formation, southwest Ordos Basin, China, and its implications

    NASA Astrophysics Data System (ADS)

    Xie, Xiangyang

    2016-04-01

    The Ordos Basin in north central China records a transition from marine to non-marine deposition during the late Paleozoic to early Mesozoic. As a result, the northern and southern regions of the Ordos Basin show different tectonic histories and very distinctive sedimentation styles. Two deformation belts, the Qinling orogenic belt to the south and the Liupanshan thrust and fold belt to the west, controlled the structural evolution of the southern Ordos Basin during the early Mesozoic. Paleocurrent analysis, net-sand ratio maps, sandstone modal analysis, and U-Pb detrital zircon geochronology were used to document sediment sources and dispersal patterns of the Triassic Yanchang Formation in the southwest Ordos Basin. Paleocurrent measurements suggest that the sediments were mainly derived from the Liupanshan and the Qinling orogenic belts. Net-sand ratio maps show that several fan delta systems controlled sediment delivery in the south Ordos Basin. Both sandstone modal analysis and U-Pb detrital zircon geochronology suggest that the Yanchang Formation is locally sourced from both of the basin marginal deformation belts; the lower and middle sections are recycled Paleozoic sedimentary rocks mainly derived from the north Qinling orogenic belt, whereas for the upper section, the Qilian-Qaidam terranes and possibly the west Qinling orogenic belt began to shed sediments into the southwest Ordos Basin. Results have important implications for basin marginal tectonics and its controls on sedimentation of intracratonic basins in China and similar settings.

  9. Event sedimentation in low-latitude deep-water carbonate basins, Anegada passage, northeast Caribbean

    USGS Publications Warehouse

    Chaytor, Jason D.; ten Brink, Uri S.

    2015-01-01

    The Virgin Islands and Whiting basins in the Northeast Caribbean are deep, structurally controlled depocentres partially bound by shallow-water carbonate platforms. Closed basins such as these are thought to document earthquake and hurricane events through the accumulation of event layers such as debris flow and turbidity current deposits and the internal deformation of deposited material. Event layers in the Virgin Islands and Whiting basins are predominantly thin and discontinuous, containing varying amounts of reef- and slope-derived material. Three turbidites/sandy intervals in the upper 2 m of sediment in the eastern Virgin Islands Basin were deposited between ca. 2000 and 13 600 years ago, but do not extend across the basin. In the central and western Virgin Islands Basin, a structureless clay-rich interval is interpreted to be a unifite. Within the Whiting Basin, several discontinuous turbidites and other sand-rich intervals are primarily deposited in base of slope fans. The youngest of these turbidites is ca. 2600 years old. Sediment accumulation in these basins is low (−1) for basin adjacent to carbonate platform, possibly due to limited sediment input during highstand sea-level conditions, sediment trapping and/or cohesive basin walls. We find no evidence of recent sediment transport (turbidites or debris flows) or sediment deformation that can be attributed to the ca. M7.2 1867 Virgin Islands earthquake whose epicentre was located on the north wall of the Virgin Islands Basin or to recent hurricanes that have impacted the region. The lack of significant appreciable pebble or greater size carbonate material in any of the available cores suggests that submarine landslide and basin-wide blocky debris flows have not been a significant mechanism of basin margin modification in the last several thousand years. Thus, basins such as those described here may be poor recorders of past natural hazards, but may provide a long-term record of past oceanographic

  10. Sediment conditions in the San Antonio River Basin downstream from San Antonio, Texas, 2000-13

    USGS Publications Warehouse

    Ockerman, Darwin J.; Banta, J. Ryan; Crow, Cassi L.; Opsahl, Stephen P.

    2015-01-01

    Sediment plays an important role in the ecological health of rivers and estuaries and consequently is an important issue for water-resource managers. To better understand sediment characteristics in the San Antonio River Basin, the U.S. Geological Survey, in cooperation with the San Antonio River Authority, completed a two-part study in the San Antonio River Basin downstream from San Antonio, Texas, to (1) collect and analyze sediment data to characterize sediment conditions and (2) develop and calibrate a watershed model to simulate hydrologic conditions and suspended-sediment loads during 2000–12.

  11. Indus Basin sediment provenance constrained using garnet geochemistry

    NASA Astrophysics Data System (ADS)

    Alizai, Anwar; Clift, Peter D.; Still, John

    2016-08-01

    The chemical and mineralogical diversity of western Himalayan rivers is the result of each of them draining different tectonic and lithologic units, whose character is partly transferred to the sediments carried by those rivers. Garnet geochemistry was employed to discriminate provenance in the Indus River system. We characterized the geochemistry of garnet sediment grains from the modern Indus and all its major tributaries, as well as the related but ephemeral Ghaggar-Hakra River and dune sand from the Thar Desert. Garnet geochemistry displays a unique signature for the Himalayan rivers on the east of the Indus drainage compared to those in the western drainage. The trunk Indus remains distinct because of the dominant arc-type pyrope-garnet derived from Kohistan and the Karakoram. The Jhellum, which lies just east of the modern Indus has modest concentrations of arc-type pyrope garnets, which are more depleted in the other eastern tributaries. Their presence in the Jhellum reflects recycling of trunk Indus garnets through the Miocene Siwalik Group foreland sedimentary rocks. The Thar Desert dune sample contains significant numbers of grains similar to those in the trunk Indus, likely reworked by monsoon winds from the SW. Our data further indicate the presence of a Himalayan river channel east of the present Indus, close to the delta, in the Nara River valley during the middle Holocene. Sands from this channel cannot be distinguished from the Indus on the basis of their garnet geochemistry alone but we favour their sedimentation from an Indus channel rather than reworking of desert sands by another stream. The garnet geochemistry shows some potential as a provenance tool, but cannot be used alone to uniquely discriminate Indus Basin provenance.

  12. A sediment trap intercomparison experiment in the Panama Basin, 1979

    NASA Astrophysics Data System (ADS)

    Honjo, Susumu; Spencer, Derek W.; Gardner, Wilford D.

    1992-02-01

    In order to compare the collection efficiency of settling particles among sediment traps in a variety of design concepts, 28 sediment traps of 11 different designs were deployed at six depths ranging from 665 to 3769 m along five rigid mooring anchored in a sill-protected marginal basin about 3865 m deep for about 4 months from August to November 1979. The traps represented three basic designs: (1) cylinders with an aspect ratio between 2 and 3; (2) funnels with a large opening covered by a baffle with a small grid and (3) open boxes whose openings were covered by a baffle. All but two of these types of participating traps had a mechanism to isolate the collected sample. Monitoring instruments indicate that all moorings provided a stable platform throughout the duration of Sediment Trap Intercomparison Experiment (STIE) with relatively low current velocity at the middle layers and very low velocity at the deep layers. Total mass flux, fluxes of three size fractions after water sieving, carbonate, combustible and noncombustible fractions, organic carbon, nitrogen and other sedimentary constituents in the individual samples were determined and evaluated with regard to the relative consistency in terms of depth and statistical tests on the similarity of the constituents. Under the conditions tested, the trapping efficiency of settling particles between a large funnel trap with baffle and an intermediate-sized cylinder trap was nearly identical considering the laboratory analytical errors. This conclusion might be extended to cylinder traps with diameters as small as 7 cm and a large aspect ratio when deployed rigidly in a low energy ocean environment. A funnel-type trap with a more effective baffle had a higher collecting efficiency than the other traps. Because of mechanical problems, comparison of the box-type traps to the other types was inconclusive.

  13. Channel evolution and hydrologic variations in the Colorado River basin: Factors influencing sediment and salt loads

    USGS Publications Warehouse

    Gellis, A.; Hereford, R.; Schumm, S.A.; Hayes, B.R.

    1991-01-01

    Suspended-sediment and dissolved-solid (salt) loads decreased after the early 1940s in the Colorado Plateau portion of the Colorado River basin, although discharge of major rivers - the Colorado, Green and San Juan - did not change significantly. This decline followed a period of high sediment yield caused by arroyo cutting. Reduced sediment loads have previously been explained by a change in sediment sampling procedures or changes in climate, land-use and conservation practices. More recent work has revealed that both decreased sediment production and sediment storage in channels of tributary basins produced the decline of sediment and salt loads. Sediment production and sediment storage are important components of incised-channel evolution, which involves sequential channel deepening, widening and finally floodplain formation. Accordingly, the widespread arroyo incision of the late nineteenth century resulted initially in high sediment loads. Since then, loads have decreased as incised channels (arroyos) have stabilized and begun to aggrade. However, during the 1940s, a period of low peak discharges permitted vegetational colonization of the valley floors, which further reduced sediment loads and promoted channel stabilization. This explanation is supported by experimental studies and field observations. Both geomorphic and hydrologic factors contributed to sediment storage and decreased sediment and salt loads in the upper Colorado River basin. ?? 1991.

  14. Process-based distributed modeling approach for analysis of sediment dynamics in a river basin

    NASA Astrophysics Data System (ADS)

    Kabir, M. A.; Dutta, D.; Hironaka, S.

    2010-08-01

    Modeling of sediment dynamics for developing best management practices of reducing soil erosion and of sediment control has become essential for sustainable management of watersheds. Precise estimation of sediment dynamics is very important since soils are a major component of enormous environmental processes and sediment transport controls lake and river pollution extensively. Different hydrological processes govern sediment dynamics in a river basin, which are highly variable in spatial and temporal scales. This paper presents a process-based distributed modeling approach for analysis of sediment dynamics at river basin scale by integrating sediment processes (soil erosion, sediment transport and deposition) with an existing process-based distributed hydrological model. In this modeling approach, the watershed is divided into an array of homogeneous grids to capture the catchment spatial heterogeneity. Hillslope and river sediment dynamic processes have been modeled separately and linked to each other consistently. Water flow and sediment transport at different surface grids and river nodes are modeled using one-dimensional kinematic wave approximation of Saint-Venant equations. The mechanics of sediment dynamics are integrated into the model using representative physical equations after a comprehensive review. The model has been tested on river basins in two different hydro climatic areas, the Abukuma River Basin, Japan and Latrobe River Basin, Australia. Sediment transport and deposition are modeled using Govers transport capacity equation. All spatial datasets, such as, Digital Elevation Model (DEM), land use and soil classification data, etc., have been prepared using raster "Geographic Information System (GIS)" tools. The results of relevant statistical checks (Nash-Sutcliffe efficiency and R-squared value) indicate that the model simulates basin hydrology and its associated sediment dynamics reasonably well. This paper presents the model including

  15. Process-based distributed modeling approach for analysis of sediment dynamics in a river basin

    NASA Astrophysics Data System (ADS)

    Kabir, M. A.; Dutta, D.; Hironaka, S.

    2011-04-01

    Modeling of sediment dynamics for developing best management practices of reducing soil erosion and of sediment control has become essential for sustainable management of watersheds. Precise estimation of sediment dynamics is very important since soils are a major component of enormous environmental processes and sediment transport controls lake and river pollution extensively. Different hydrological processes govern sediment dynamics in a river basin, which are highly variable in spatial and temporal scales. This paper presents a process-based distributed modeling approach for analysis of sediment dynamics at river basin scale by integrating sediment processes (soil erosion, sediment transport and deposition) with an existing process-based distributed hydrological model. In this modeling approach, the watershed is divided into an array of homogeneous grids to capture the catchment spatial heterogeneity. Hillslope and river sediment dynamic processes have been modeled separately and linked to each other consistently. Water flow and sediment transport at different land grids and river nodes are modeled using one dimensional kinematic wave approximation of Saint-Venant equations. The mechanics of sediment dynamics are integrated into the model using representative physical equations after a comprehensive review. The model has been tested on river basins in two different hydro climatic areas, the Abukuma River Basin, Japan and Latrobe River Basin, Australia. Sediment transport and deposition are modeled using Govers transport capacity equation. All spatial datasets, such as, Digital Elevation Model (DEM), land use and soil classification data, etc., have been prepared using raster "Geographic Information System (GIS)" tools. The results of relevant statistical checks (Nash-Sutcliffe efficiency and R-squared value) indicate that the model simulates basin hydrology and its associated sediment dynamics reasonably well. This paper presents the model including descriptions

  16. Sediment discharge in the Santa Clara River Basin, Ventura and Los Angeles Counties, California

    USGS Publications Warehouse

    Williams, Rhea P.

    1979-01-01

    Sediment data collected in the Santa Clara River in California basin, during the 1967-75 water years were analyzed to determine the particle size and quantity of sediment transported past three gaging stations. The total sediment discharge of the basin , computed from records of Santa Clara River at Montalvo for water years 1968-75, was 63.5 million tons, of which 59.5 million tons was carried in suspension and an estimated 4 million tons was transported as unsampled sediment discharge. About 17.7 million tons, or 28 percent of the total sediment discharge, was coarse sediment (particles larger than 0.062 millimeter). Most of the sediment was transported during only a few days of floodflow each year. During the 1968-75 water years, approximately 55 percent of the total sediment was transported in 2 days and 92 percent was transported in 53 days. The long-term (1928-75) average annual sediment discharge of the Santa Clara River at Montalvo is estimated at 3.67 million tons. Of that quantity, 2.58 million tons consisted of fine sediment and 1.09 million tons consisted of coarse sediment. A sediment budget for the Santa Clara River basin was estimated for sediment discharges under both natural and actual conditions. The major difference between natural and actual sediment discharges of the Santa Clara River basin is the sediment intercepted upstream from Lake Piru. The combined trap efficiency of Lake Piru and Pyramid Lake approaches 100 percent. Sediment deposited in these reservoirs resulted in about a 6-percent reduction of sediment to the Santa Clara River basin during the historical period (1928-75) and a 12-percent reduction during the period most affected by dams (1953-75). Sediment losses to the basin by gravel mining, diversion of flows, and interception of sediment in the Castaic Creek basin resulted in additional reductions of 2 percent during the period 1928-75 and 4 percent during the period 1953-75. (Kosco-USGS)

  17. Relation of waterfowl poisoning to sediment lead concentrations in the Coeur d'Alene River Basin

    USGS Publications Warehouse

    Beyer, W.N.; Audet, D.J.; Heinz, G.H.; Hoffman, D.J.; Day, D.

    2000-01-01

    For many years, waterfowl have been poisoned by lead after ingesting contaminated sediment in the Coeur d'Alene River Basin, in Idaho. Results of studies on waterfowl experimentally fed this sediment were combined with results from field studies conducted in the Basin to relate sediment lead concentration to injury to waterfowl. The first step in the model estimated exposure as the relation of sediment lead concentration to blood lead concentration in mute swans (Cygnus olor), ingesting 22% sediment in a rice diet. That rate corresponded to the 90th percentile of sediment ingestion estimated from analyses of feces of tundra swans (Olor columbianus) in the Basin. Then, with additional laboratory studies on Canada geese (Branta canadensis) and mallards (Anas platyrhynchos) fed the sediment, we developed the general relation of blood lead to injury in waterfowl. Injury was quantified by blood lead concentrations, ALAD (-aminolevulinic acid dehydratase) activity, protoporphyrin concentrations, hemoglobin concentrations, hepatic lead concentrations, and the prevalence of renal nuclear inclusion bodies. Putting the exposure and injury relations together provided a powerful tool for assessing hazards to wildlife in the Basin. The no effect concentration of sediment lead was estimated as 24 mg/kg and the lowest effect level as 530 mg/kg. By combining our exposure equation with data on blood lead concentrations measured in moribund tundra swans in the Basin, we estimated that some mortality would occur at a sediment lead concentration as low as 1800 mg/kg.

  18. A reconnaissance of stream sediment in the Erie-Niagara basin, New York

    USGS Publications Warehouse

    Archer, R.J.; La Sala, A.M.

    1968-01-01

    This reconnaissance study of erosion and deposition of sediment in the Erie-Niagara basin indicates that the highest sediment yields, on the order of 1,000 tons per square mile per year, occur in streams that drain upland areas. In contrast, for example, from the lowland part of the Tonawanda Creek basin, the annual sediment yields are on the order of 100 tons per square mile per year. The estimated average annual sediment yields of streams in the basin range from 50 tons per square mile for Little Tonawanda Creek at Linden, to 1,500 tons per square mile for Cazenovia Creek at Ebenezer. These estimates are based on measured instantaneous sediment discharge at selected stream stations, the sediment loads of which ranged from 1,100 tons per year for Little Tonawanda Creek at Linden to 610,000 tons per year for Cattaraugus Creek at Gowanda. The accuracy of the estimates of average annual sediment discharge could be considerably improved by the collection of additional data. Nevertheless, the estimates are believed to be indicative of the magnitude of sediment yields and provide a general description of stream-sediment movement in the study area. Peak suspended-sediment concentrations in the range of 2,600 to 5,300 ppm (parts per million) were observed at three stations in the Cattaraugus Creek basin, as well as at Buffalo Creek at Gardenville, Cazenovia Creek at Ebenezer, and Cayuga Creek near Lancaster.

  19. Trends in suspended-sediment loads and concentrations in the Mississippi River Basin, 1950–2009

    USGS Publications Warehouse

    Heimann, David C.; Sprague, Lori A.; Blevins, Dale W.

    2011-01-01

    Trends in loads and concentrations of suspended sediment and suspended sand generally were downward for stations within the Mississippi River Basin during the 60-, 34-, and 12-year periods analyzed. Sediment transport in the lower Mississippi River has historically been, and continues to be, most closely correlative to sediment contributions from the Missouri River, which generally carried the largest annual suspended-sediment load of the major Mississippi River subbasins. The closure of Fort Randall Dam in the upper Missouri River in 1952 was the single largest event in the recorded historical decline of suspended-sediment loads in the Mississippi River Basin. Impoundments on tributaries and sediment reductions as a result of implementation of agricultural conservation practices throughout the basin likely account for much of the remaining Mississippi River sediment transport decline. Scour of the main-stem channel downstream from the upper Missouri River impoundments is likely the largest source of suspended sand in the lower Missouri River. The Ohio River was second to the Missouri River in terms of sediment contributions, followed by the upper Mississippi and Arkansas Rivers. Declines in sediment loads and concentrations continued through the most recent analysis period (1998–2009) at available Mississippi River Basin stations. Analyses of flow-adjusted concentrations of suspended sediment indicate the recent downward temporal changes generally can be explained by corresponding decreases in streamflows.

  20. Late Quaternary climate change record from two long sediment cores from Guaymas Basin, Gulf of California

    NASA Astrophysics Data System (ADS)

    Cheshire, Heather; Thurow, Jürgen; Nederbragt, Alexandra J.

    2005-07-01

    Modern Guaymas Basin (Gulf of California, Mexico) is a region of high diatom productivity where exceptional preservation factors maintain biannually alternating sediment deposition as annual varves. New sediment cores from Guaymas Basin (MD02-2512 and MD02-2515) present the opportunity to construct climate records from below the last glacial period. A low-resolution age model has been constructed from oxygen isotope analysis, correlation with other dated short piston cores from Guaymas Basin and an estimate of sedimentation rate. MD02-2512 from eastern Guaymas Basin has an age range from the Holocene to late marine isotope stage 6 (MIS 6); MD02-2515 from western Guaymas Basin has an age range from 8000 to 40 000 yr. Shipboard analyses of colour reflectance, magnetic susceptibility and sediment density are combined with continuous X-ray fluorescence scans to reconstruct a picture of glacial climate in the Gulf of California. Eastern Guaymas Basin is affected by glacial sea level fall, which results in a drastic change in productivity rates and sediment type. The laminated record of MIS 5 allows comparison with the Holocene, showing a similarity of sedimentation patterns during deglaciation and a series of very rapid variations just prior to the last glaciation. In western Guaymas Basin there are a series of Younger Dryas-like events during the glacial, typified by low productivity and high terrigenous input. Long-term climate and productivity changes appear to be caused by the southward displacement of the Subtropical High pressure zone. Copyright

  1. Tracing suspended sediment sources in the Upper Sangamon River Basin using fingerprinting techniques

    NASA Astrophysics Data System (ADS)

    Yu, M.; Rhoads, B. L.; Neal, C.; Anders, A. M.

    2014-12-01

    As the awareness of water pollution, eutrophication and other water related environmental concerns grows, the significance of sediment in the transport of nutrients and contaminants from agricultural areas to streams has received increasing attention. Both the physical and geochemical properties of suspended sediment are strongly controlled by sediment sources. Thus, tracing sources of suspended sediment in watersheds is important for the design of management practices to reduce sediment loads and contributions of sediment-adsorbed nutrients from agricultural areas to streams. However, the contributions of different sediment sources to suspended sediment loads within intensively managed watersheds in the Midwest still remain insufficiently explored. This study aims to assess the provenance of suspended sediment and the relation between channel morphology and production of suspended sediment in the Upper Sangamon River Basin, Illinois. The 3,690-km2 Upper Sangamon River Basin is characterized by low-relief, agricultural lands dominated by row-crop agriculture. Sediment source samples were collected in the Saybrook and Wildcat Slough sub-watersheds from six potential sources: row-crop agriculture, forest, floodplains, river banks, pastures, and grasslands. Event-based suspended sediment samples were collected by in situ suspended sediment samplers and ISCO automatic pump samplers from the streams. A quantitative geochemical fingerprinting technique, combining statistically verified multicomponent signatures and an unmixing model, was employed to estimate the relative contributions of sediment from six potential sources to the suspended sediment loads. Our preliminary results indicate that the majority of suspended sediment is derived from channel banks and forest adjacent to meandering reaches in the downstream portions of the watersheds, while only minor amounts of suspended sediment are derived from upland areas adjacent to channelized rivers in the low

  2. Multistate Evaluation of Microbial Water and Sediment Quality from Agricultural Recovery Basins.

    PubMed

    Partyka, Melissa L; Bond, Ronald F; Chase, Jennifer A; Kiger, Luana; Atwill, Edward R

    2016-03-01

    Agricultural recovery basins are an important conservation practice designed to provide temporary storage of sediment and water on farms before low-volume discharge. However, food safety concerns have been raised regarding redistribution of captured sediment and water to fields used for human food production. The purpose of this study was to examine the potential microbiological risk that recovery basins may contribute to nearby produce fields and to evaluate characteristics that may influence or mitigate those risks. Water and sediment samples were collected from participating farms in three states and evaluated for bacterial indicators and pathogens over several months. Overall, 45% ( = 48) of water samples and less than 15% ( = 13) of sediment samples were positive for spp. In water samples, the occurrence of was positively associated with the use of surface water as a source of irrigation compared with groundwater as well as log-scale increases in concentration. In sediment samples, was associated with basin location (region) and basin fill levels. Sediment exposed to drying during dewatering had lower concentrations of indicator and a lower proportion of positives than submerged sediment from the same pond. Surrounding landscape characteristics, including vegetative coverage, proximity to livestock operations, and evidence of wildlife, were not correlated with pathogen occurrence in either sediment or water samples, suggesting that although habitat surrounding ponds may be an attractant to wildlife, those features may not contribute to increased pathogen occurrence in agricultural recovery basins. PMID:27065413

  3. Suspended-Sediment Budget for the North Santiam River Basin, Oregon, Water Years 2005-08

    USGS Publications Warehouse

    Bragg, Heather M.; Uhrich, Mark A.

    2010-01-01

    Significant Findings An analysis of sediment transport in the North Santiam River basin during water years 2005-08 indicated that: Two-thirds of sediment input to Detroit Lake originated in the upper North Santiam River subbasin. Two-thirds of the sediment transported past Geren Island originated in the Little North Santiam River subbasin. The highest annual suspended-sediment load at any of the monitoring stations was the result of a debris flow on November 6, 2006, on Mount Jefferson. About 86 percent of the total sediment input to Detroit Lake was trapped in the lake, whereas 14 percent was transported farther downstream. More than 80 percent of the sediment transport in the basin was in November, December, and January. The variance in the annual suspended-sediment loads was better explained by the magnitude of the annual peak streamflow than by the annual mean streamflow.

  4. Sediment yields in a thick loess region: The Missouri River basin

    SciTech Connect

    Bettis, E.A. III

    1995-12-31

    Sediment yields in the thick loess region of the Missouri River basin are among the highest in North America. The combination of high local relief, easily eroded loessal surficial deposits, entrenched stream systems, and a humid climate foster high erosion rates and sediment yields. Stratigraphic investigations in over twenty watersheds within the thick loess region have documented the magnitude of several episodes of Holocene sediment movement and storage. Spatial and temporal patterns of sediment storage vary within a given drainage basin, but are similar in like-size elements of different basins. These patterns suggest that intrinsic controls are as important a climate in the long-term behavior of this fluvial system. The magnitude and pattern of Holocene sediment accumulation during the Historic period is similar to that which occurred on at least one occasion during the prehistoric period when the landscape was little modified by human activity.

  5. Temporal and basin-specific population trends of quagga mussels on soft sediment of a multi-basin reservoir

    USGS Publications Warehouse

    Caldwell, Timothy J; Rosen, Michael R.; Chandra, Sudeep; Acharya, Kumud; Caires, Andrea M; Davis, Clinton J.; Thaw, Melissa; Webster, Daniel M.

    2015-01-01

    Invasive quagga (Dreissena bugnesis) and zebra (Dreissena ploymorpha) mussels have rapidly spread throughout North America. Understanding the relationships between environmental variables and quagga mussels during the early stages of invasion will help management strategies and allow researchers to predict patterns of future invasions. Quagga mussels were detected in Lake Mead, NV/AZ in 2007, we monitored early invasion dynamics in 3 basins (Boulder Basin, Las Vegas Bay, Overton Arm) bi-annually from 2008-2011. Mean quagga density increased over time during the first year of monitoring and stabilized for the subsequent two years at the whole-lake scale (8 to 132 individuals·m-2, geometric mean), in Boulder Basin (73 to 875 individuals·m-2), and in Overton Arm(2 to 126 individuals·m-2). In Las Vegas Bay, quagga mussel density was low (9 to 44 individuals·m-2), which was correlated with high sediment metal concentrations and warmer (> 30°C) water temperatures associated with that basin. Carbon content in the sediment increased with depth in Lake Mead and during some sampling periods quagga density was also positively correlated with depth, but more research is required to determine the significance of this interaction. Laboratory growth experiments suggested that food quantity may limit quagga growth in Boulder Basin, indicating an opportunity for population expansion in this basin if primary productivity were to increase, but was not the case in Overton Arm. Overall quagga mussel density in Lake Mead is highly variable and patchy, suggesting that temperature, sediment size, and sediment metal concentrations, and sediment carbon content all contribute to mussel distribution patterns. Quagga mussel density in the soft sediment of Lake Mead expanded during initial colonization, and began to stabilize approximately 3 years after the initial invasion.

  6. Current-controlled, abyssal microtopography and sedimentation in Mozambique Basin, southwest Indian Ocean

    USGS Publications Warehouse

    Kolla, V.; Eittreim, S.; Sullivan, L.; Kostecki, J.A.; Burckle, L.H.

    1980-01-01

    The Antarctic Bottom Water (AABW) activity and the variations in the abundance and grain size of the terrigenous sediments, derived from Africa and Madagascar land masses, are reflected in different types of microtopography in the Mozambique Basin. In southerly areas, where the sediment supply is much less, the bottom-current activity has resulted in the presence of manganese nodules, a thin veneer of sediments, and the absence of sediment waves. Farther north, along the marginal areas of the basin where the fine-grained sediments from the Africa-Madagascar source have been supplied in abundance, wavy bedforms have been generated by AABW. Wavy bedforms do not exist even in the northerly areas if coarse-grained, turbidite sediments are present on the sea floor. The continuation of acoustic reflectors from the zone of turbidites in the central areas of the basin into the zone of sediment waves along the margins, and the lithology and structures in sediment cores from these zones suggest that the turbidity-current-fed, fine-grained sediments were deposited as wavy bedforms by AABW flow. Thus, sediment waves formed readily during Pleistocene times. The enrichment of quartz and displaced Antarctic diatoms, and the relatively low kaolinite/chlorite ratios in the sediments, the north-pointing current lineations on the sea floor, the lack of any perceptible sedimentary fill in the troughs of waves, and the dense nepheloid layer in the westerly areas of the Mozambique Basin, attest to the current-controlled sedimentation and generation of wavy bedforms during Holocene time also. The formation of sediment waves in the Mozambique Basin can be modeled after a fluvial antidune mechanism. This model envisages that internal waves, focussed on a benthic boundary layer cap, have been locked in phase with sediment waves in the presence of an 8-10 cm/sec current in the Mozambique Basin. A density contrast of 2??10-6 g/cm3 appears to exist at the tops of benthic boundary layers in the

  7. Basin-wide sediment trapping efficiency of emerging reservoirs along the Mekong

    NASA Astrophysics Data System (ADS)

    Kummu, M.; Lu, X. X.; Wang, J. J.; Varis, O.

    2010-07-01

    The Mekong Basin has remained relatively intact, but the current plans for rapid development in the hydropower sector may threaten the riverine ecosystems. Should all the plans be materialized in tributaries and mainstream, the cumulative active storage capacity of the reservoirs would increase more than tenfold from the present level to around 20% of the annual discharge of the Mekong (505 km 3). In this study a protocol is developed to estimate the trapping efficiency ( TE) of the existing and planned reservoirs in the Mekong Basin based on Brune's method. The existing reservoirs have a basin TE of 15-18% and should all the planned reservoirs be built, this will increase to 51-69%. However, due to the high heterogeneity of the specific sediment yield in different parts of the basin, the trapped sediment load ( TSL) is predicted to be much higher. The existing and planned mainstream dams in the Chinese part of the river have the largest impact on the river sediment load ( SL) as more than 60% of the basin SL originates from this stretch of the river. The three existing reservoirs in that part of the basin have potential to trap annually approximately 32-41 Mt of sediment. If the entire cascade of eight dams is constructed, TE will increase to 78-81%, and potentially 70-73 Mt, i.e. more than 50% of the total basin sediment load (˜ 140 Mt) will be trapped annually.

  8. Sedimentation and subsidence patterns in the central and north basins of Lake Baikal from seismic stratigraphy

    USGS Publications Warehouse

    Moore, T.C.; Klitgord, Kim D.; Golmshtok, A.J.; Weber, E.

    1997-01-01

    Comparison of sedimentation patterns, basement subsidence, and faulting histories in the north and central basins of Lake Baikal aids in developing an interbasinal seismic stratigraphy that reveals the early synrift evolution of the central portion of the Baikal rift, a major continental rift system. Although there is evidence that the central and northern rift basins evolved at approximately the same time, their sedimentation histories are markedly different. Primary sediment sources for the initial rift phase were from the east flank of the rift; two major deltas developed adjacent to the central basin: the Selenga delta at the south end and the Barguzin delta at the north end. The Barguzin River system, located at the accommodation zone between the central and north basins, also fed into the southern part of the north basin and facilitated the stratigraphic linkage of the two basins. A shift in the regional tectonic environment in the mid Pliocene(?) created a second rift phase distinguished by more rapid subsidence and sediment accumulation in the north basin and by increased subsidence and extensive faulting in the central basin. The Barguzin delta ceased formation and parts of the old delta system were isolated within the north basin and on Academic Ridge. These isolated deltaic deposits provide a model for the development of hydrocarbon plays within ancient rift systems. In this second tectonic phase, the dominant sediment fill in the deeper and more rapidly subsiding north basin shifted from the flexural (eastern) margin to axial transport from the Upper Angara River at the north end of the basin.

  9. Present and potential sediment yields in the Yampa River Basin, Colorado and Wyoming

    USGS Publications Warehouse

    Andrews, Edmund D.

    1978-01-01

    Average annual suspended- and total-sediment loads in streamflow were determined by the flow-duration sediment-transport-curve method at 18 sites in the Yampa River basin, Colorado and Wyoming. These computations indicate that about 2.0 million tons of sediment are carried by the Yampa River at Deerlodge Park during an average year. Significant areal differences in the sediment yield from various parts of the basin also were determined. The lower Little Snake River subbasin contributes about 60 percent of the total basin sediment yield, although it represents less than 35 percent of the area and supplies less than 3 percent of the streamflow. In contrast, the upland (eastern) one-third of the basin contributes only about 14 percent of the sediment yield but 76 percent of the streamflow. Projected economic development of the basin, especially surface mining of coal, will impact the physical environment. Depending upon the amount and location of land disturbed, an estimated 10 ,000 to 30,000 tons per year of additional sediment will be contributed to the main-stem Yampa River. (Woodard-USGS)

  10. Late quaternary sediment sources, storage and transfers within mountain basins using clast lithological analysis: Pineta Basin, central Pyrenees, Spain

    NASA Astrophysics Data System (ADS)

    Jones, A. P.

    2000-09-01

    Understanding basin-wide sediment dynamics, both spatially and temporally, is an important antecedent to eventual quantitative interpretation of sediment transfer within mountain fluvial systems. This paper describes an attempt to trace sediment transfer modes and pathways using clast lithological analysis in a small mountain basin strongly influenced by glaciation: the Pineta Basin in the central Pyrenees of Spain. The paper interprets slope-channel interaction by encompassing the whole basin, enabling staged sedimentary pathways to be revealed. Additionally, bed-material textures of the modern rivers and youngest La Sarra Terrace were investigated to provide further information on the geomorphic coupling of the system. Relatively few studies have taken this approach. Glacial and later, fluvial systems transferred the sediments creating laterally extensive, polylithological sediment stores. Local depositional systems overprint this inherited signature. To what extent depends on the size and energy of the local system. Significant impacts are made by conduits, such as large-scale fluvially dominated fans and waterfalls, which deliver local lithologies to the main river. Conduits may be part of the main river system or part of the tributary system. Conduits are the most important elements when considering provenance studies and theoretical modelling.

  11. Sedimentation and tectonics in the southern Bida Basin, Nigeria: depositional response to varying tectonic context

    SciTech Connect

    Braide, S.P. )

    1990-05-01

    The Upper Cretaceous Bida basin of central Nigeria is sandwiched between the Precambrian schist belts of the Northern Nigerian massif and the West African craton. Of interest is the southern part of the basin, which developed in continental settings, because the facies architecture of the sedimentary fill suggests a close relation between sedimentation dynamics and basin margin tectonics. This relationship is significant to an understanding of the basin's origin, which has been controversial. A simple sag and rift origin has been suggested, and consequently dominated the negative thinking on the hydrocarbon prospects of the basin which were considered poor. This detailed study of the facies indicates rapid basin-wide changes from various alluvial fan facies through flood-basin and deltaic facies to lacustrine facies. Paleogeographic reconstruction suggests lacustrine environments were widespread and elongate. Lacustrine environments occurred at the basin's axis and close to the margins. This suggests the depocenter must have migrated during the basin's depositional history and subsided rapidly to accommodate the 3.5-km-thick sedimentary fill. Although distinguishing pull-apart basins from rift basins, based solely on sedimentologic grounds, may be difficult, the temporal migration of the depocenter, as well as the basin architecture of upward coarsening cyclicity, show a strong tectonic and structural overprint that suggests a tectonic framework for the Southern Bida basin similar in origin to a pull-apart basin.

  12. Thermal alteration of organic matter in recent marine sediments. 2: Isoprenoids. [Tanner Basin off Southern California

    NASA Technical Reports Server (NTRS)

    Ikan, R.; Baedecker, M. J.; Kaplan, I. R.

    1974-01-01

    A series of isoprenoid compounds were isolated from a heat treated marine sediment (from Tanner Basin) which were not present in the original sediment. Among the compounds identified were: phytol, dihydrophytol, c-18-isoprenoid ketone, phytanic and pristanic acids, c-19 and c-20-monoolefines, and the alkanes pristane and phytane. The significance and possible routes leading to these compounds is discussed.

  13. Historical suspended sediment data in the Tennessee and Cumberland River basins

    SciTech Connect

    Brown, R.T. ); Carey, W.P. . Water Resources Div.)

    1989-07-01

    This report summarizes the available daily suspended sediment data for the Tennessee and Cumberland river basins. These historical data provide an overview of sediment yield and stream transport of suspended sediment (SS) from a variety of watersheds and stream locations within these river basins. Almost all of these data were collected by the Tennessee Valley Authority (TVA) or the United States Geological Survey (USGS) during the past 50 years. The monthly summaries of these daily data presented in this report are intended to: document the period of record for the sampling sites, show the strong effects of hydrologic conditions on sediment yield and transport patterns, and demonstrate similarities in sediment response among the different watersheds sampled. Many other stations have been sampled periodically for suspended sediment. This report documents only the daily records because these provide the most accurate estimates of average concentrations and loads. 15 refs., 116 figs., 111 tabs.

  14. Metamorphism of Triassic sediments from the Dunbarton Basin, South Carolina

    SciTech Connect

    Snipes, D.S.; Warner, R.D. . Earth Sciences Dept.); Price, V. Jr. ); Thayer, P. . Geology Dept.)

    1993-03-01

    Modal analyses and microprobe studies were performed on eight core samples obtained from the US Geological Survey Well A1 324. The well is situated in the southern part of the buried Triassic Dunbarton Basin, about 1 km south of the US Department of Energy's Westinghouse Savannah River Company Site. The samples came from an interval of 407.0--413.4 m beneath the land surface. At the well site, Triassic red beds are overlain by Late Cretaceous and Tertiary sediments which have an aggregate thickness of 408 m. The sample from a depth of 407 m is a weathered, poorly sorted, clayey sandstone from the basal portion of the Late Cretaceous Cape Fear Formation. This specimen is not metamorphosed; whereas, the Triassic specimens taken from an interval of 411.6--413.4 m exhibit evidence of thermal metamorphism as well as hydrothermal alteration. In hand specimen, three of the samples (412.8--413.4 m) resemble hornfelses. These samples exhibit decussate texture. Results of modal analyses of the two deepest specimens follow: plagioclase (43-52%), quartz (9-23%), chlorite (22-29%), epidote (1-6%), hematite (3-4%), and magnetite (2-3%). Relict detrital quartz grains, especially the finer ones, are mostly angular-to-subangular and the grain boundaries show little evidence of rounding. The authors feel that hydrothermal alteration was the principal metamorphic process. This belief is supported by the fact that most of the plagioclase has undergone extensive sericitization. In addition, the presence of abundant chlorite together with a minor amount of epidote supports this interpretation. The alteration halo extends upward for 1.8 m. This interpretation is based on the observation that two Triassic arkose sandstone specimens (411.6 m, 412.2 m) contain clouded, slightly sericitized K-feldspar and plagioclase grains in a matrix of red-colored smectite.

  15. Reconnaissance of sedimentation in the Rio Pilcomayo Basin, May 1975, Argentina, Bolivia, and Paraguay

    USGS Publications Warehouse

    Ritter, John R.

    1977-01-01

    The Rio Pilcomayo ' Alto ' (Bolivia) and ' Superior ' (Bolivia, Argentina, and Paraguay) transport large quantities of sediment for the size of the basin. The Rio Pilcomayo ' Inferior ' (Argentina and Paraguay) carries little sediment. The large loads of the ' Alto ' and ' Superior ' must be considered before dams or irrigation projects are started. The shifting channel and flooding of the Rio Pilcomayo ' Superior ' also are problems to be considered before development. The Rio Pilcomayo ' Alto ' basin has relatively little sediment deposition whereas the ' Superior ' basin has considerable deposition. A part of the ' Superior ' channel is filled with sediment to the top of its banks. The upstream limit of filling is moving farther upstream each year causing the place of overbank flooding to move upstream also. (Woodard-USGS)

  16. Paleomagnetic isochrons, unsteadiness, and uniformity of sedimentation in Miocene intermontane basin sediments at Salla, eastern Andean cordillera, Bolivia

    SciTech Connect

    McRae, L.E. )

    1990-07-01

    Fine-scaled stratigraphic data are combined with chronologic information provided by paleomagnetic stratigraphy to document and analyze chronostratigraphic variability of the Salla Beds, a sequence of distal floodplain and lacustrine intermontane basin sediments within the eastern Andean cordillera of Bolivia. Unsteadiness in sediment accumulation is identified using a conceptual model of episodic accumulation in which simulated accumulation histories are constructed using estimated rates for various fluvial facies and taking into account gaps in deposition and possible effects of erosion. Variability in the Salla Beds is compared to that in sequence of Miocene fluvial sediments in northern Pakistan to evaluate controls on spatial and temporal stratigraphic variability. Sedimentation in the Salla sequence was generally steady over short time scales, but over longer intervals infrequent carbonates, associated with unusually long hiatuses, served to reduce the net sediment accumulation rate. In the Chinji sequence of Pakistan, unsteady accumulation evolved into a pattern of steadier sediment accumulation as recurring cycles of unsteadiness were superimposed on the overall sequence. The controls on sediment accumulation over time in these two sequences may be similarly related to the presence and extent of atypical and infrequent events of deposition, non-deposition, or erosion that exert a significant effect on net sediment accumulation. The discrepancy of short-term episodic and long-term net stratigraphic accumulation rates in both these sequences suggests that the decrease in net sediment accumulation rate with increasing time reflects the superimposed effects of different levels of local geomorphic and extrabasinal controls.

  17. Eocene sediment dispersal pattern records asymmetry of Laramide Green River basin, southwestern Wyoming

    SciTech Connect

    Baldwin, R.J.; Andersen, D.W.

    1987-05-01

    Provenance and paleocurrent data from synorogenic fluvial sandstones can be used to constrain theories about the timing and structural style of Laramide foreland uplifts and associated basins. The Green River basin of southwestern Wyoming is a large ellipsoidal basin bounded by uplifts with diverse orientations and basement rock compositions. Sandstone from the main body of the Eocene Wasatch Formation in the Green River basin was sampled along the south and west flanks of the Rock Springs uplift. Petrographic examination and paleocurrent measurements reveal two main facies. The first facies is rich in feldspar and metamorphic rock fragments derived from the Wind River Mountains to the north. The second facies is dominated by quartz and sedimentary rock fragments, reflecting a source in the Uinta Mountains to the south. Distribution of these facies indicates that a sediment lobe extends 15 km into the basin from the Uinta Mountains. Another sediment lobe originates from the Wind River Mountains and extends approximately 100 km south into the basin. This pattern suggests that the topographic axis of the depositional basin was an east-west-trending trough about 15 km north of the Uinta Mountains. The position of the basin axis is inferred to reflect greater subsidence near the Uinta Mountains. The asymmetric distribution of the two facies of the Wasatch Formation thus supports the model of basin subsidence caused by thrust-loading and indicates the Uinta Mountains were the dominant active thrust block bounding the Green River basin during the early Eocene.

  18. Analysis of sediment production from two small semiarid basins in Wyoming

    USGS Publications Warehouse

    Rankl, J.G.

    1987-01-01

    Data were collected at two small, semiarid basins in Wyoming to determine the relation between rainfall, runoff, and sediment production. The basins were Dugout Creek tributary and Saint Marys Ditch tributary. Sufficient rainfall and runoff data were collected at Dugout Creek tributary to determine the source of sediment and the dominant sediment production processes. Because runoff from only one storm occurred in Saint Marys Ditch tributary, emphasis of the study was placed on the analysis of data collected at Dugout Creek tributary. At Dugout Creek tributary, detailed measurements were made to establish the source of sediment. To determine the quantity of material removed from headcuts during the study, two headcuts were surveyed. Aerial photographs were used to define movement of all headcuts. The total quantity of sediment removed from all headcuts between September 26, 1982, and September 26, 1983, was estimated to be 1,220 tons, or 15%-25% of the estimated total sediment load passing the streamflow-gaging station. A soil plot was used to sample upland erosion. A rainfall and runoff modeling system was used to evaluate the interaction between the physical processes which control sediment production. The greatest change in computed sediment load was caused by changing the parameter values for equations used to compute the detachment of sediment particles by rainfall and overland flow resulted in very small changes in computed sediment load. The upland areas were the primary source of sediment. A relationship was developed between the peak of storm runoff and the total sediment load for that storm runoff. The sediment concentration used to compute the total sediment load for the storm runoff was determined from sediment samples collected by two automatic pumping samplers. The coefficient of variation of the relationship is 34% with a 0.99 correlation coefficient. (Author 's abstract)

  19. Morphology and Late Quaternary sedimentation in the Gulf of Oman Basin

    NASA Astrophysics Data System (ADS)

    Uchupi, Elazar; Swift, S. A.; Ross, D. A.

    The morphology of the Gulf of Oman Basin, a 3,400 m deep oceanic basin between Oman and southern Pakistan and southern Iran, ranges from a convergent margin (Makran margin) along the north side, a passive type (Oman margin) along the south side, translation types along the basin's west (Zendan Fault-Oman Line) and east (Murray Ridge) sides and a narrow continental rise and a wide abyssal plain in the centre of the basin. Sediment input into the basin during the Late Quaternary has been mainly from the north as a result of the uplift of the Coast Makran Mountains in the Late Miocene-Pliocene. Today most of this detritrus is deposited on the shelf and upper continental slope and perched basins behind the fold/fault ridges on the lower slope. The presence of fans and channels on the continental rise on the north side of the basin indicate, however, that continental derived debris was, and possibly is, being transported to the deep-sea by turbidity currents via gaps in the ridges on the lower slope. In addition to land derived terrigenous sediments, the basin deposits also contain biogenic (organic matter and calcium carbonate), eolian detritus and hydrates and authigenic carbonates from the tectonic dewatering of the Makran accretionary wedge. The eolian sediment is carried into the Gulf of Oman Basin from Arabia and the Mesopotamia Valley by the northwesterly Shamal winds. This type of detritus was particularly abundant during the glacial arid periods 21,000-20,000 and 11,000 (Younger Dryas) years ago when exposure of the Persian (Arabian) Gulf increased the area of dust entrainment and shifted the position of the source of the eolian sediments closer to the basin.

  20. Aliphatic hydrocarbons in sediment cores from the southern basin of Lake Michigan

    SciTech Connect

    Doskey, P.V.; Andren, A.W.

    1991-10-01

    Aliphatic hydrocarbons in sediments of the southern basin of Lake Michigan have planktonic, terrigenous, and petroleum residue origins. Surficial sediments collected near the eastern shore in 60-80 m of water contained more petroleum residue and planktonic hydrocarbons and exhibited less terrigenous character than sediments collected from the deepest location in the basin. Petroleum residue inputs have increased since 1900 as evidenced by a change in the flux of an unresolved complex mixture (UCM) of hydrocarbons from 6 ng/cm{sup 2}{center_dot}yr to a flux of approximately 100 ng/cm{sup 2}{center_dot}yr in 1980. Sediment profiles of the UCM exhibited subsurface concentration maxima that may be due to reduced inputs of combustion products or feeding by oligochaetes. Profiles of n-C{sub l7} and pristane indicated that planktonic n-alkanes undergo degradation in the aerobic, mixed zone of the sediments.

  1. Erosion, sediment discharge, and channel morphology in the Upper Chattahoochee River basin, Georgia

    USGS Publications Warehouse

    Faye, Robert E.; Carey, W.R.; Stamer, J.K.; Kleckner, R.L.

    1978-01-01

    Average annual rates of sheet erosion and sediment discharge were computed for several watersheds in the Upper Chattahoochee River basin in Georgia. Erosion yields ranged from about 900 to 6,000 tons per year per square mile in nine watersheds and were greatest where land use is largely agricultural or transitional. Suspended sediment yields from the same watershed ranged from about 300 to 800 tons per year per square mile and were greatest from urban areas and least from mostly forested watersheds. The impact of suspended sediment on stream quality was evaluated for 14 watersheds. In general, 60 percent or more of the total annual discharge of trace metals and phosphorus was contributed by suspended sediment. Yields of trace metals and nutrients in suspension were consistently greater in urban watersheds. Turbidity in basin streams increased geometrically with increasing concentrations of suspended sediment. (Woodard-USGS)

  2. Impact of Placer Mining on Sediment Transport in Headwaters of the Lake Baikal Basin.

    NASA Astrophysics Data System (ADS)

    Pietron, J.; Jarsjo, J.; Chalov, S.

    2015-12-01

    Adverse practices in alluvial surface mining (placer mining) can lead to shifts in sediment transport regimes of rivers. However, some placer mines are located in remote parts of river basins, which constrain data availability in mining impact assessments. One such mining area is the Zaamar Goldfield (Northern Mongolia) which stretches 60 km along the Tuul River. The area is located in the headwaters of the Lake Baikal Basin, and may impact the UNESCO World Heritage Site of Lake Baikal. Previous studies indicate that the mining industry in the Zaamar Goldfield loads the river system with considerable amount of contaminated sediments (heavy metals). Still, transport processes and possible changes in local to regional sediment transport need to be better understood. In this work, we use snapshot field measurements and various flow and transport modelling techniques to analyze (1) the impact of placer mining in the sediment delivery to the river system and (2) the dynamics of further sediment transport to downstream Tuul River. Our results indicate that surface mining operations and waste management have considerable impact on the sediment input from the landscape. Furthermore, dynamic in-channel storage of sediments can act as intermittent sources of mining sediments. These effects occur in addition to impacts of on-going changes in hydro-climatic conditions of the area. We hope that our methodology and results will aid in studying similar unmonitored and mining-affected river basins.

  3. Seepage basin radionuclide transport in sediments and vegetation. Revision 1

    SciTech Connect

    Murphy, C.E. Jr.; Jerome, K.M.

    1993-12-31

    Radionuclide concentrations were measured in soil and vegetation growing adjacent to and in the Savannah River Laboratory Seepage Basins as part of the plan for closure of the basin system. The results of the measurements provide some information about the mobility of the radionuclides introduced into the basins. {sup 90}Sr is the most mobile of the radionuclides in soil. Its high mobility and high relative uptake by vegetation cause {sup 90}Sr to be distributed throughout the basin system. {sup 137}Cs is not as mobile in the basin soil, limiting its uptake by vegetation growing on the edge of the seepage basins; however, it is readily taken up by the vegetation growing in the basins. Soil mobility and vegetation uptake is relatively low for all of the transuranic radionuclides. For the most part these radionuclides remain near the surface of the basin soils where they were absorbed from the waste-water. The relative role of soil mobility and vegetation uptake on the distribution of radionuclide at the basins was futher evaluated by comparing the vegetation concentration ratio and the half-depth of penetration of the radionuclides in the basin soil. The results suggest that vegetation processes dominate in determining the concentration of {sup 60}Co and {sup 137}Cs in the vegetation. The influences of soil and vegetation are more balanced for {sup 90}Sr. The other radionuclides exhibit both low soil mobility and low vegetation uptake. The lack of soil mobility is seen in the lower concentrations found in vegetation growing on the edge of the basin compared to those growing in the basin.

  4. Statistical modelling of suspended sediment load in small basin located in the tropical Andes of Colombia

    NASA Astrophysics Data System (ADS)

    Montoya, L. J.; Barco, J.

    2014-12-01

    Sedimentation is a complex process that varies with watershed characteristics, climate dynamics, human watershed intervention, etc. The sediment load is a concern as it reduces the operating capacity of reservoirs. In this study a statistical modelling for the estimation of sediment yield based on observations of water discharge and suspended sediment concentration was performed. A multivariate model was used to analyze a 33 years period of daily suspended sediments load available at the La Garrucha gauging station. A regional analysis was conducted to develop a non-dimensional sediment load duration curves. These duration curves were used to estimate flow and sediments regimen at other inner point at the basin where there are located the Calderas reservoir, scaling the suspended sediment load by the basin area. The observed data of sediments in the reservoir were used to validate the model results. The obtained non-dimensional sediment load duration curve was used to estimate the sediment concentration during high flow regimen (10% of time the values were met or exceeded).A periodical reservoir flushing, by the opening of the bottom gate, it is necessary to maintain it at the best operating capacity. The sediment concentration during high flows has been assumed as a concentration that allows an 'environmental flushing'. The sediment transport capacity for the sediment load was verified with a 1D model in order to include the environmental constraints downstream of the dam. Field data were collected to understand the physical phenomena involved in flushing dynamics into the reservoir and downstream of the dam. The model allows to define an operation rules for the flushing to minimize the environmental effects.

  5. Sediment and nutrient accumulation within lowland bottomland ecosystems: An example from the Atchafalaya River Basin, Louisiana

    USGS Publications Warehouse

    Hupp, C.R.; Noe, G.B.

    2006-01-01

    Sediment and nutrient deposition, storage, and transformations are important environmental functions of riverine forested wetland ecosystems, yet documentation and interpretation of sedimentation/nutrient processes remain incomplete. Our studies located in the Coastal Plain of southeastern USA, including the Atchafalaya Basin, La. (a distributary of the Mississippi River) serve as example for detailed discussion of sediment and nutrient accumulation in lowland systems. The Atchafalaya Basin is the largest contiguously forested riparian wetland in North America and is incurring high sediment loads and hypoxic zones in backswamp settings. We established several floodplain transects, located to reflect major depositional environments within the Basin, to monitor general and local sediment deposition patterns over a multi-year period. Deposition rate and loss on ignition (LOI) data were collected above artificial markers (clay pads) at multiple stations along each transect. Mean floodplain sedimentation rates ranged from about 2 to 42 mm/yr and mean percent organic material ranged from about 7 to 28 percent. The transects were categorized into statistically different deposition groups based on sedimentation rate; most of these groups could be coherently interpreted based on a suite of parameters that includes hydroperiod (elevation), source(s) of sediment-laden water, hydraulic connectivity, flow stagnation, and location in transect (levee versus backswamp). Low elevatic (long hydroperiod), high hydraulic connectivity to multiple sources of sediment-laden water, and hydraulic damming (flow stagnation) lead to the highest amounts of sediment trapping; the converse in any of these factors may diminish sediment trapping. Based on aerial extent of deposition groups, the study area (about 500 km 2) potentially traps 6.72+109 kg of sediment, annually, of which 12 percent or 8.20.108 kg are organic material. This accumulated sediment contains a coarsely estimated 5% and 27

  6. Fate and Transport of Cohesive Sediment and HCB in the Middle Elbe River Basin

    NASA Astrophysics Data System (ADS)

    Moshenberg, Kari; Heise, Susanne; Calmano, Wolfgang

    2014-05-01

    Chemical contamination of waterways and floodplains is a pervasive environmental problem that threatens aquatic ecosystems worldwide. Due to extensive historical contamination and redistribution of contaminated sediments throughout the basin, the Elbe River transports significant loads of contaminants downstream, particularly during flood events. This study focuses on Hexachlorobenzene (HCB), a persistent organic pollutant that has been identified as a contaminant of concern in the Elbe Basin. To better understand the fate and transport of cohesive sediments and sediment-sorbed HCB, a hydrodynamic, suspended sediment, and contaminated transport model for the 271-km reach of the Elbe River basin between Dresden and Magdeburg was developed. Additionally, trends in suspended sediment and contaminant transport were investigated in the context of the recent high frequency of floods in the Elbe Basin. This study presents strong evidence that extreme high water events, such as the August, 2002 floods, have a permanent effect on the sediment transport regime in the Elbe River. Additionally, results indicate that a significant component annual HCB loads are transported downstream during floods. Additionally, modeled results for suspended sediment and HCB accumulation on floodplains are presented and discussed. Uncertainty and issues related to model development are also addressed. A worst case analysis of HCB uptake by dairy cows and beef cattle indicate that significant, biologically relevant quantities of sediment-sorbed HCB accumulate on the Elbe floodplains following flood events. Given both the recent high frequency of floods in the Elbe Basin, and the potential increase in flood frequency due to climate change, an evaluation of source control measures and/or additional monitoring of floodplain soils and grasses is recommended.

  7. Sediment supply as a driver of river evolution in the Amazon Basin

    NASA Astrophysics Data System (ADS)

    Ahmed, Joshua; Constantine, José Antonio; Dunne, Thomas; Legleiter, Carl; Lazarus, Eli D.

    2015-04-01

    The Amazon represents the only large river basin in the world where there is a sufficient range of sediment supplies and a lack of engineering controls to assess how sediment supply drives the evolution of meandering rivers. Despite recent analytical advances (Asahi et al., 2013; Pittaluga and Seminara, 2011), modern theory does not yet identify or explain the effects of externally imposed sediment supplies, a fundamental river characteristic, on meandering river evolution. These sediment supplies would be radically reduced by the construction of large dams proposed for the Amazon Basin (Finer and Jenkins, 2012). Here, we demonstrate that the sediment loads imposed by their respective drainage basins determine planform changes in lowland rivers across the Amazon. Our analysis, based on Landsat image sequences, indicates that rivers with high sediment loads draining the Andes and associated foreland basin experience annual migration rates that are on average four times faster than rivers with lower sediment loads draining the Central Amazon Trough and shields. Incidents of meander cutoff also occur more frequently along the rivers of the Andes and foreland basin, where the number of oxbows in the floodplains is more than twice that observed in the floodplains of the Central Amazon Trough and shields. Our results, which cannot be explained by differences in channel slope or hydrology, highlight the importance of sediment supply in modulating the ability of meandering alluvial rivers to reshape the floodplain environment through river migration. Asahi, K., Shimizu, Y., Nelson, J., Parker, G., 2013. Numerical simulation of river meandering with self-evolving banks. Journal of Geophysical Research: Earth Surface, 118(4), 2013JF002752. Finer, M., Jenkins, C.N., 2012. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity. PLOS One, 7(4), e35126. Pittaluga, M.B., Seminara, G., 2011. Nonlinearity and unsteadiness in river

  8. Using 10Be and 26Al to determine sediment generation rates and identify sediment source areas in an arid region drainage basin

    NASA Astrophysics Data System (ADS)

    Clapp, Erik M.; Bierman, Paul R.; Caffee, Marc

    2002-06-01

    We measured 10Be and 26Al in 64 sediment and bedrock samples collected throughout the arid, 187 km 2 Yuma Wash drainage basin, southwestern Arizona. From the measurements, we determine long-term, time-integrated rates of upland sediment generation (81±5 g m -2 year -1) and bedrock equivalent lowering (30±2 m Ma -1) consistent with other estimates for regions of similar climate, lithology, and topography. In a small (˜8 km 2), upland sub-basin, differences in nuclide concentrations between bedrock outcrops and hillslope colluvium suggest weathering of bedrock beneath a colluvial cover is a more significant source of sediment (40×10 4 kg year -1) than weathering of exposed bedrock surfaces (10×10 4 kg year -1). Mixing models constructed from nuclide concentrations of sediment reservoirs identify important sediment source areas. Hillslope colluvium is the dominant sediment source to the upper reaches of the sub-basin channel; channel cutting of alluvial terraces is the dominant source in the lower reaches. Similarities in nuclide concentrations of various sediment reservoirs indicate short sediment storage times (<10 3 years). Nuclide concentrations, measured in channel sediment from tributaries of Yuma Wash and in samples collected along the length of the Wash, were used to construct mixing models and determine sediment sources to the main stem channel. We find an exponential decrease in the channel nuclide concentrations with distance downstream, suggesting that as much as 40% of sediment discharged from Yuma Wash has been recycled from storage within basin fill alluvium. Sediment generation and denudation rates determined from the main stem are greater (25%) than rates determined from upland sub-basins suggesting that, currently, sediment may be exported from the basin more quickly than it is being generated in the uplands. Independence of nuclide concentration and sediment grain size indicates that channels transport sediment in discrete pulses before rapidly

  9. Fault-controlled sedimentation in a progressively opening extensional basin: the Palaeoproterozoic Vargfors basin, Skellefte mining district, Sweden

    NASA Astrophysics Data System (ADS)

    Bauer, Tobias E.; Skyttä, Pietari; Allen, Rodney L.; Weihed, Pär

    2013-03-01

    The Vargfors basin in the central part of the Skellefte mining district is an inverted sedimentary basin within a Palaeoproterozoic (1.89 Ga) marine volcanic arc. The fault-segmented basin formed from upper-crustal extension and subsequent compression, following a period of intense sub-marine volcanism and VMS ore formation. New detailed mapping reveals variations in stratigraphy attributed to syn-extensional sedimentation, as well as provenance of conglomerate clasts associated with tectonic activity at the transition from extension to compression. The onset of fan delta to alluvial fan sedimentation associated with basin subsidence indicates that significant dip-slip displacement accommodating rapid uplift of the intrusive complex and/or subsidence of the adjacent volcano-sedimentary domain took place along a major fault zone at the southern margin of the intrusive complex. Subsidence of the Jörn intrusive complex and/or its burial by sedimentary units caused a break in erosion of the intrusion and favoured the deposition of a tonalite clast-barren conglomerate. Clast compositions of conglomerates show that the syn-extensional deposits become younger in the south-eastern parts of the basin, indicating that opening of the basin progressed from north-west to south-east. Subsequent basin inversion, associated with the accretion to the Karelian margin, involved reverse activation of the normal faults and development of related upright synclines. Progressive crustal shortening caused the formation of break-back faults accompanied by mafic volcanic activity that particularly affected the southern contact of the Jörn intrusive complex and the northern contact of the Vargfors basin.

  10. Gully development in Pavon Creeks: Downstream sediment supply and sub-basin restoration

    NASA Astrophysics Data System (ADS)

    Pearce, S.; McKee, L. J.

    2011-12-01

    Sediment supply in watersheds is a function of geology, climate, and land use. Small watersheds in the Coast Ranges of California can provide large volumes of sediment to downstream waterbodies due to the active tectonic setting, the Mediterranean climate, and the history of intense land use. The Pavon Creeks sub-basin, a 1.1 km2 tributary to Pinole Creek which drains to San Francisco Bay, California, currently provides a large supply of fine-grained sediment to the detriment of creek function and native species habitat. The sub-basin is situated near the active Hayward Fault Zone, is underlain by highly erosive shales and siltstones, and has experienced over 100 years of cattle grazing. Despite only comprising 3% of the total watershed area, the Pavon Creeks sub-basin has been identified as one of the largest sources of fine sediment within the Pinole Creek watershed. To protect creek function and habitat, watershed stakeholders have prioritized preventing excess fine sediment delivery to Pinole Creek. The sub-basin includes four small ephemeral gully channels that are primarily actively eroding, downcutting, and extending over their length, and secondarily aggrading over a shorter localized reach. Field-based geomorphic data including channel cross-sections, longitudinal profiles, bank pins, and headcut monitoring have documented channel incision, erosion, and lengthening of the channel network over six years. During Water Year 2006, the first and wettest year of measurements, we observed maximum rates of incision of 0.75 m, lateral bank erosion of 2.5 m, and gully extension of 16.3 m. Annual repeat surveys show continued gully evolution, and allowed for quantitative assessment of incision, aggradation, and extension rates over this time period, as well as eroded sediment volume. We found that the largest storm events of a season cause the greatest instantaneous amount of change in the sub-basin, but cumulative seasonal rainfall determines the total amount and

  11. Coarse-grained deltaic sedimentation in the Miocene Cuyama strike-slip basin, California Coast Ranges

    USGS Publications Warehouse

    Alan, Bartow J.

    1990-01-01

    The Cuyama basin, located in the southern Coast Ranges of California southwest of the San Andreas fault, developed early in the history of the San Andreas transform system. The Miocene marine basin formed in a transtensional setting along a dextral strike-slip fault of the transform system following Oligocene non-marine basin formation in an extensional setting. The lower and middle Miocene Vaqueros Formation in the northwestern part of the basin, which represents the first of two transgressive-regressive cycles, is described here in terms of nine facies in two broad facies groups. The 400-m-thick Soda Lake Shale Member (of the Vaqueros) comprises deep-basin and starved-basin facies. A thin transgressive facies occurs locally at the base of the formation. The overlying Painted Rock Sandstone Member (of the Vaqueros), which is more than 2200 m thick and consists mostly of coarse-grained sandstone and pebbly sandstone, constitutes a delta complex of prodelta, slope channel, delta front, tide-influenced distributary channel, interdistributary bay, and fluvial channel facies. The basinal depositional system consisted of turbidite mud and sand, and hemipelagic and pelagic sediments of the basinal facies deposited in a rapidly subsiding basin. The delta depositional system consisted of the delta complex facies that prograded into the deep basin and had a steep prodelta slope that extended to bathyal depths. The delta is inferred to be a mixed fluvial-wave-dominated fan delta, analogous in its delta-front morphology and processes to a fjord delta, in which coarse sediment delivered to the delta front by braided streams was transported down the prodelta slope into deep water by sediment gravity flows. Transgression and rapid deepening of the basin in the early Miocene coincided with rapid tectonic subsidence. Deepening culminated with deposition of a starved-basin facies or condensed section at the time of maximum transgression, which was followed by the beginning of a

  12. Deconvoluting Himalayan Climate and Tectonics Based on Zada Basin Sediments, Southwestern Tibet

    NASA Astrophysics Data System (ADS)

    Saylor, J. E.; Decelles, P. G.; Quade, J.; Kapp, P.

    2005-12-01

    The Zada basin of southwestern Tibet is the largest late Cenozoic basin on the Tibetan plateau. The basin developed above the Tethyan Himalayan sequence and is located between major detachment faults to the northwest and southeast, the Ayi Shan Mountains along the dextral Karakoram fault to the northeast, and a major newly recognized dextral strike slip fault to the southwest. However, Zada basin fill is presently flat-lying, buttressing paleotopography along its northern and southern margins and not spatially associated with the South Tibetan detachment system. The Zada basin records one major pulse of accommodation creation as indicated by basal debris flows and fluvial pebble conglomerates. Paleocurrent data show transverse flow along basin margins and axial NW-ward flow along the basin center. A period of lacustrine sedimentation followed, with deposition of multiple, upward coarsening calcareous clay - fine sand para-sequences within an overall progradational sequence. The sands display turbidites, oscillatory current ripples, mudcracks, hummocky cross-stratification and planar and trough cross-stratification. Fossils, primarily gastropods, ostracods, fish and rare large vertebrates, are found in both the lower fluvial and also lacustrine/fluvial units. An alluvial fan boulder conglomerate caps the basin fill. Subsequent incision by the Sutlej River following breaching of a structural dam in the western corner of the basin created spectacular bluffs and canyons. The basin contains a sedimentary record extending back to the late Miocene. As such, it records the regional C3 - C4 transition and associated climate change at 7 - 8 Ma. The extensive lacustrine deposits also provide an excellent source of paleoelevation data. Paleosol carbonates in the basal and capping conglomerates extend this data set to the onset of sedimentation in the basin. Finally, sedimentary provenance, basin subsidence history, and regional structure give insight into the causes of

  13. Stream sediment sources in midwest agricultural basins with land retirement along channel

    USGS Publications Warehouse

    Williamson, Tanja N.; Christensen, Victoria G.; Richardson, William B.; Frey, Jeffrey W.; Gellis, Allen C.; Kieta, K. A.; Fitzpatrick, Faith A.

    2014-01-01

    Documenting the effects of agricultural land retirement on stream-sediment sources is critical to identifying management practices that improve water quality and aquatic habitat. Particularly difficult to quantify are the effects from conservation easements that commonly are discontinuous along channelized streams and ditches throughout the agricultural midwestern United States. Our hypotheses were that sediment from cropland, retired land, stream banks, and roads would be discernible using isotopic and elemental concentrations and that source contributions would vary with land retirement distribution along tributaries of West Fork Beaver Creek in Minnesota. Channel-bed and suspended sediment were sampled at nine locations and compared with local source samples by using linear discriminant analysis and a four-source mixing model that evaluated seven tracers: In, P, total C, Be, Tl, Th, and Ti. The proportion of sediment sources differed significantly between suspended and channel-bed sediment. Retired land contributed to channel-bed sediment but was not discernible as a source of suspended sediment, suggesting that retired-land material was not mobilized during high-flow conditions. Stream banks were a large contributor to suspended sediment; however, the percentage of stream-bank sediment in the channel bed was lower in basins with more continuous retired land along the riparian corridor. Cropland sediments had the highest P concentrations; basins with the highest cropland-sediment contributions also had the highest P concentrations. Along stream reaches with retired land, there was a lower proportion of cropland material in suspended sediment relative to sites that had almost no land retirement, indicating less movement of nutrients and sediment from cropland to the channel as a result of land retirement.

  14. Stream Sediment Sources in Midwest Agricultural Basins with Land Retirement along Channel.

    PubMed

    Williamson, T N; Christensen, V G; Richardson, W B; Frey, J W; Gellis, A C; Kieta, K A; Fitzpatrick, F A

    2014-09-01

    Documenting the effects of agricultural land retirement on stream-sediment sources is critical to identifying management practices that improve water quality and aquatic habitat. Particularly difficult to quantify are the effects from conservation easements that commonly are discontinuous along channelized streams and ditches throughout the agricultural midwestern United States. Our hypotheses were that sediment from cropland, retired land, stream banks, and roads would be discernible using isotopic and elemental concentrations and that source contributions would vary with land retirement distribution along tributaries of West Fork Beaver Creek in Minnesota. Channel-bed and suspended sediment were sampled at nine locations and compared with local source samples by using linear discriminant analysis and a four-source mixing model that evaluated seven tracers: In, P, total C, Be, Tl, Th, and Ti. The proportion of sediment sources differed significantly between suspended and channel-bed sediment. Retired land contributed to channel-bed sediment but was not discernible as a source of suspended sediment, suggesting that retired-land material was not mobilized during high-flow conditions. Stream banks were a large contributor to suspended sediment; however, the percentage of stream-bank sediment in the channel bed was lower in basins with more continuous retired land along the riparian corridor. Cropland sediments had the highest P concentrations; basins with the highest cropland-sediment contributions also had the highest P concentrations. Along stream reaches with retired land, there was a lower proportion of cropland material in suspended sediment relative to sites that had almost no land retirement, indicating less movement of nutrients and sediment from cropland to the channel as a result of land retirement. PMID:25603248

  15. Estimation of Streamflow and Fluvial Sediment Loads in the White Volta Basin under Future Climate Change

    NASA Astrophysics Data System (ADS)

    Lumor, M.; Amisigo, B. A.

    2015-12-01

    The White Volta Basin is one of the major sub-catchments of the Volta Basin of West Africa, covers an estimated 106,000 km2 and is shared between Burkina Faso and Ghana. The basin currently faces many challenges such as flooding, drought, high temporal and spatial variation of rainfall, deforestation, land degradation, climate change and high population growth rate. These challenges put pressure on the quantity and quality of the water resources in the basin. Current infrastructure developments in the basin have already impacted on the hydrological cycle, and future development plans potentially pose a threat to the sustainability of the resources if not appropriately managed. Information on runoff and sediment loads is a very important requirement for sustainable management of the water resources in the basin. This study therefore seeks to assess runoff and sediment loads in the White Volta Basin using the Soil Water Assessment Tool (SWAT) and provide understanding of how climate change impacts on future runoff and sediment loads in the basin.The model was calibrated for the period 1991 to 2003 and validated for the period 2004 to 2013.The model was also validated at one gauging station on the main river and another on a tributary. Analysis of the water balance of the basin shows that 4.90% of the simulated mean annual precipitation is converted to surface runoff while 84.37% evapotranspires. The results also show that the White Volta Basin contributes approximately 5.68x106tonnes/yr of sediment load into the Volta Lake. The calibrated model was used to simulate the water balance for the present time slice (1975-2005) as the basis for comparing with the future (2025-2055) water balance in the WhiteVolta Basin. The results show that annual surface runoff and sediment loads could increase by 56% and 70% respectively. A projected reduction by 0.54% in actual evapotranspiration is however estimated for the selected time period in the basin.

  16. Adapting SWAT hillslope erosion model to predict sediment concentrations and yields in large Basins.

    PubMed

    Vigiak, Olga; Malagó, Anna; Bouraoui, Fayçal; Vanmaercke, Matthias; Poesen, Jean

    2015-12-15

    The Soil and Water Assessment Tool (SWAT) is used worldwide for water quality assessment and planning. This paper aimed to assess and adapt SWAT hillslope sediment yield model (Modified Universal Soil Loss Equation, MUSLE) for applications in large basins, i.e. when spatial data is coarse and model units are large; and to develop a robust sediment calibration method for large regions. The Upper Danube Basin (132,000km(2)) was used as case study representative of large European Basins. The MUSLE was modified to reduce sensitivity of sediment yields to the Hydrologic Response Unit (HRU) size, and to identify appropriate algorithms for estimating hillslope length (L) and slope-length factor (LS). HRUs gross erosion was broadly calibrated against plot data and soil erosion map estimates. Next, mean annual SWAT suspended sediment concentrations (SSC, mg/L) were calibrated and validated against SSC data at 55 gauging stations (622 station-years). SWAT annual specific sediment yields in subbasin reaches (RSSY, t/km(2)/year) were compared to yields measured at 33 gauging stations (87station-years). The best SWAT configuration combined a MUSLE equation modified by the introduction of a threshold area of 0.01km(2) where L and LS were estimated with flow accumulation algorithms. For this configuration, the SSC residual interquartile was less than +/-15mg/L both for the calibration (1995-2004) and the validation (2005-2009) periods. The mean SSC percent bias for 1995-2009 was 24%. RSSY residual interquartile was within +/-10t/km(2)/year, with a mean RSSY percent bias of 12%. Residuals showed no bias with respect to drainage area, slope, or spatial distribution. The use of multiple data types at multiple sites enabled robust simulation of sediment concentrations and yields of the region. The MUSLE modifications are recommended for use in large basins. Based on SWAT simulations, we present a sediment budget for the Upper Danube Basin. PMID:26356993

  17. Adapting SWAT hillslope erosion model to predict sediment concentrations and yields in large Basins.

    PubMed

    Vigiak, Olga; Malagó, Anna; Bouraoui, Fayçal; Vanmaercke, Matthias; Poesen, Jean

    2015-12-15

    The Soil and Water Assessment Tool (SWAT) is used worldwide for water quality assessment and planning. This paper aimed to assess and adapt SWAT hillslope sediment yield model (Modified Universal Soil Loss Equation, MUSLE) for applications in large basins, i.e. when spatial data is coarse and model units are large; and to develop a robust sediment calibration method for large regions. The Upper Danube Basin (132,000km(2)) was used as case study representative of large European Basins. The MUSLE was modified to reduce sensitivity of sediment yields to the Hydrologic Response Unit (HRU) size, and to identify appropriate algorithms for estimating hillslope length (L) and slope-length factor (LS). HRUs gross erosion was broadly calibrated against plot data and soil erosion map estimates. Next, mean annual SWAT suspended sediment concentrations (SSC, mg/L) were calibrated and validated against SSC data at 55 gauging stations (622 station-years). SWAT annual specific sediment yields in subbasin reaches (RSSY, t/km(2)/year) were compared to yields measured at 33 gauging stations (87station-years). The best SWAT configuration combined a MUSLE equation modified by the introduction of a threshold area of 0.01km(2) where L and LS were estimated with flow accumulation algorithms. For this configuration, the SSC residual interquartile was less than +/-15mg/L both for the calibration (1995-2004) and the validation (2005-2009) periods. The mean SSC percent bias for 1995-2009 was 24%. RSSY residual interquartile was within +/-10t/km(2)/year, with a mean RSSY percent bias of 12%. Residuals showed no bias with respect to drainage area, slope, or spatial distribution. The use of multiple data types at multiple sites enabled robust simulation of sediment concentrations and yields of the region. The MUSLE modifications are recommended for use in large basins. Based on SWAT simulations, we present a sediment budget for the Upper Danube Basin.

  18. Spatio-temporal patterns of soil erosion and suspended sediment dynamics in the Mekong River Basin.

    PubMed

    Suif, Zuliziana; Fleifle, Amr; Yoshimura, Chihiro; Saavedra, Oliver

    2016-10-15

    Understanding of the distribution patterns of sediment erosion, concentration and transport in river basins is critically important as sediment plays a major role in river basin hydrophysical and ecological processes. In this study, we proposed an integrated framework for the assessment of sediment dynamics, including soil erosion (SE), suspended sediment load (SSL) and suspended sediment concentration (SSC), and applied this framework to the Mekong River Basin. The Revised Universal Soil Loss Equation (RUSLE) model was adopted with a geographic information system to assess SE and was coupled with a sediment accumulation and a routing scheme to simulate SSL. This framework also analyzed Landsat imagery captured between 1987 and 2000 together with ground observations to interpolate spatio-temporal patterns of SSC. The simulated SSL results from 1987 to 2000 showed the relative root mean square error of 41% and coefficient of determination (R(2)) of 0.89. The polynomial relationship of the near infrared exoatmospheric reflectance and the band 4 wavelength (760-900nm) to the observed SSC at 9 sites demonstrated the good agreement (overall relative RMSE=5.2%, R(2)=0.87). The result found that the severe SE occurs in the upper (China and Lao PDR) and lower (western part of Vietnam) regions. The SSC in the rainy season (June-November) showed increasing and decreasing trends longitudinally in the upper (China and Lao PDR) and lower regions (Cambodia), respectively, while the longitudinal profile of SSL showed a fluctuating trend along the river in the early rainy season. Overall, the results described the unique spatio-temporal patterns of SE, SSL and SSC in the Mekong River Basin. Thus, the proposed integrated framework is useful for elucidating complex process of sediment generation and transport in the land and river systems of large river basins.

  19. Spatio-temporal patterns of soil erosion and suspended sediment dynamics in the Mekong River Basin.

    PubMed

    Suif, Zuliziana; Fleifle, Amr; Yoshimura, Chihiro; Saavedra, Oliver

    2016-10-15

    Understanding of the distribution patterns of sediment erosion, concentration and transport in river basins is critically important as sediment plays a major role in river basin hydrophysical and ecological processes. In this study, we proposed an integrated framework for the assessment of sediment dynamics, including soil erosion (SE), suspended sediment load (SSL) and suspended sediment concentration (SSC), and applied this framework to the Mekong River Basin. The Revised Universal Soil Loss Equation (RUSLE) model was adopted with a geographic information system to assess SE and was coupled with a sediment accumulation and a routing scheme to simulate SSL. This framework also analyzed Landsat imagery captured between 1987 and 2000 together with ground observations to interpolate spatio-temporal patterns of SSC. The simulated SSL results from 1987 to 2000 showed the relative root mean square error of 41% and coefficient of determination (R(2)) of 0.89. The polynomial relationship of the near infrared exoatmospheric reflectance and the band 4 wavelength (760-900nm) to the observed SSC at 9 sites demonstrated the good agreement (overall relative RMSE=5.2%, R(2)=0.87). The result found that the severe SE occurs in the upper (China and Lao PDR) and lower (western part of Vietnam) regions. The SSC in the rainy season (June-November) showed increasing and decreasing trends longitudinally in the upper (China and Lao PDR) and lower regions (Cambodia), respectively, while the longitudinal profile of SSL showed a fluctuating trend along the river in the early rainy season. Overall, the results described the unique spatio-temporal patterns of SE, SSL and SSC in the Mekong River Basin. Thus, the proposed integrated framework is useful for elucidating complex process of sediment generation and transport in the land and river systems of large river basins. PMID:27338846

  20. Water and sediment quality in the Yukon River basin, Alaska, during water year 2004

    USGS Publications Warehouse

    Schuster, Paul F.

    2006-01-01

    This report contains water-quality and sediment-quality data from samples collected in the Yukon River Basin from March through September during the 2004 water year (WY). Samples were collected throughout the year at five stations in the basin (three on the main stem Yukon River, one each on the Tanana and Porcupine Rivers). A broad range of physical, chemical, and biological analyses are presented.

  1. Occurrence and distribution of hexabromocyclododecane in sediments from seven major river drainage basins in China.

    PubMed

    Li, Honghua; Shang, Hongtao; Wang, Pu; Wang, Yawei; Zhang, Haidong; Zhang, Qinghua; Jiang, Guibin

    2013-01-01

    The concentrations and geographical distribution of hexabromocyclododecane (HBCD) were investigated in 37 composite surface sediments from seven major river drainage basins in China, including Yangtze River, Yellow River, Pearl River, Liaohe River, Haihe River, Tarim River and Ertix River. The detection frequency of HBCD was 54%, with the concentrations ranged from below limit of detection (LOD) to 206 ng/g dry weight. In general, the geographical distribution showed increasing trends from the upper reaches to the lower reaches of the rivers and from North China to Southeast China. Compared to other regions in the world, the average concentration of HBCD in sediments from Yangtze River drainage basin was at relatively high level, whereas those from other six river drainage basins were at lower or similar level. The highest HBCD concentration in sediment from Yangtze River Delta and the highest detection frequency of HBCD in Pearl River drainage basins suggested that the industrial and urban activities could evidently affect the HBCD distribution. HBCD diastereoisomer profiles showed that gamma-HBCD dominated in most of the sediment samples, followed by alpha- and beta-HBCD, which was consistent with those in the commercial HBCD mixtures. Further risk assessment reflected that the average inventories of HBCD were 18.3, 5.87, 3.92, 2.50, 1.77 ng/cm2 in sediments from Pearl River, Haihe River, Tarim River, Yellow River and Yangtze River, respectively. PMID:23586301

  2. Occurrence and distribution of hexabromocyclododecane in sediments from seven major river drainage basins in China.

    PubMed

    Li, Honghua; Shang, Hongtao; Wang, Pu; Wang, Yawei; Zhang, Haidong; Zhang, Qinghua; Jiang, Guibin

    2013-01-01

    The concentrations and geographical distribution of hexabromocyclododecane (HBCD) were investigated in 37 composite surface sediments from seven major river drainage basins in China, including Yangtze River, Yellow River, Pearl River, Liaohe River, Haihe River, Tarim River and Ertix River. The detection frequency of HBCD was 54%, with the concentrations ranged from below limit of detection (LOD) to 206 ng/g dry weight. In general, the geographical distribution showed increasing trends from the upper reaches to the lower reaches of the rivers and from North China to Southeast China. Compared to other regions in the world, the average concentration of HBCD in sediments from Yangtze River drainage basin was at relatively high level, whereas those from other six river drainage basins were at lower or similar level. The highest HBCD concentration in sediment from Yangtze River Delta and the highest detection frequency of HBCD in Pearl River drainage basins suggested that the industrial and urban activities could evidently affect the HBCD distribution. HBCD diastereoisomer profiles showed that gamma-HBCD dominated in most of the sediment samples, followed by alpha- and beta-HBCD, which was consistent with those in the commercial HBCD mixtures. Further risk assessment reflected that the average inventories of HBCD were 18.3, 5.87, 3.92, 2.50, 1.77 ng/cm2 in sediments from Pearl River, Haihe River, Tarim River, Yellow River and Yangtze River, respectively.

  3. Sediment Bacterial Communities Reflect the History of a Sea Basin

    PubMed Central

    Lyra, Christina; Sinkko, Hanna; Rantanen, Matias; Paulin, Lars; Kotilainen, Aarno

    2013-01-01

    How entire microbial communities are structured across stratified sediments from the historical standpoint is unknown. The Baltic Sea is an ideal research object for historical reconstruction, since it has experienced many fresh- and brackish water periods and is depleted of dissolved oxygen, which increases the sediment's preservation potential. We investigated the bacterial communities, chemical elements (e.g. Cr, Pb Na, P, Sr and U) and sediment composition in a stratified sediment core dated by radiocarbon and spanning 8000 years of Baltic Sea history, using up-to-date multivariate statistics. The communities were analysed by 16S rRNA gene terminal restriction fragment length polymorphism. The communities of the deep Early Litorina and surface Late Litorina Sea laminae were separated from the communities of the middle Litorina Sea laminae, which were associated with elevated concentrations of U and Sr trace elements, palaeo-oxygen and palaeosalinity proxies. Thus, the Litorina Sea laminae were characterized by past oxygen deficiency and salinity increase. The communities of the laminae, bioturbated and homogeneous sediments were differentiated, based on the same historical sea phases, with correct classifications of 90%. Palaeosalinity was one of the major parameters that separated the bacterial communities of the stratified sediments. A discontinuous spatial structure with a surprising increase in community heterogeneity was detected in Litorina Sea sediments from 388 to 422 cm deep, which suggests that a salinity maximum occurred in the central Gulf of Finland app. 6200–6600 years ago. The community heterogeneity decreased from the surface down to 306 cm, which reflected downcore mineralization. The plateau of the decrease was in the app. 2000-year-old sediment layers. Bacterial community data may be used as an additional tool in ocean-drilling projects, in which it is important to detect mineralization plateaus both to determine historically comparable

  4. Sediment bacterial communities reflect the history of a sea basin.

    PubMed

    Lyra, Christina; Sinkko, Hanna; Rantanen, Matias; Paulin, Lars; Kotilainen, Aarno

    2013-01-01

    How entire microbial communities are structured across stratified sediments from the historical standpoint is unknown. The Baltic Sea is an ideal research object for historical reconstruction, since it has experienced many fresh- and brackish water periods and is depleted of dissolved oxygen, which increases the sediment's preservation potential. We investigated the bacterial communities, chemical elements (e.g. Cr, Pb Na, P, Sr and U) and sediment composition in a stratified sediment core dated by radiocarbon and spanning 8000 years of Baltic Sea history, using up-to-date multivariate statistics. The communities were analysed by 16S rRNA gene terminal restriction fragment length polymorphism. The communities of the deep Early Litorina and surface Late Litorina Sea laminae were separated from the communities of the middle Litorina Sea laminae, which were associated with elevated concentrations of U and Sr trace elements, palaeo-oxygen and palaeosalinity proxies. Thus, the Litorina Sea laminae were characterized by past oxygen deficiency and salinity increase. The communities of the laminae, bioturbated and homogeneous sediments were differentiated, based on the same historical sea phases, with correct classifications of 90%. Palaeosalinity was one of the major parameters that separated the bacterial communities of the stratified sediments. A discontinuous spatial structure with a surprising increase in community heterogeneity was detected in Litorina Sea sediments from 388 to 422 cm deep, which suggests that a salinity maximum occurred in the central Gulf of Finland app. 6200-6600 years ago. The community heterogeneity decreased from the surface down to 306 cm, which reflected downcore mineralization. The plateau of the decrease was in the app. 2000-year-old sediment layers. Bacterial community data may be used as an additional tool in ocean-drilling projects, in which it is important to detect mineralization plateaus both to determine historically comparable

  5. Quantifying spatial patterns and timescales of fine sediment redistribution in river basins: application of a sediment budget model with fallout radionuclide tracers

    NASA Astrophysics Data System (ADS)

    Smith, Hugh; Blake, William; Taylor, Alex

    2013-04-01

    Improved understanding of fine sediment and associated contaminant redistribution within river basins requires information on the sources and rates of sediment supply alongside the timescales of downstream sediment transfer. Sediment budgets are an effective tool for examining these patterns. While small, intensively monitored research catchments may provide such information, the examination of larger scale patterns of sediment transfer often requires the use of modelling-based approaches. Furthermore, knowledge of timescales of fine sediment transfer in river basins is limited. Few studies link sediment budgets with explicit information on the residence or travel times of fine sediment. This information is essential for understanding contemporary patterns of river basin sediment redistribution, and has implications for predicting possible recovery times of rivers affected by contaminated sediment from historic or recent pollution. Against this background, we aim to quantify the spatial patterns and timescales of suspended sediment transfer through a river basin (917 km2) situated in south-west England. We apply a spatially-distributed sediment budget model (SedNet) in conjunction with high-resolution spatial data and long-term rainfall and river flow measurements. Model outputs provide an indication of mean annual patterns of sediment redistribution and yields, which were computed for three land cover surveys. This modelling was coupled with techniques for estimating fine sediment residence times, which are based on differences in the decay rates of three fallout radionuclides (Be-7, excess Pb-210 and Cs-137). Findings from this study demonstrate the need for more integrated approaches to better understand spatial patterns and timescales of sediment redistribution in river basins.

  6. Recent changes of water discharge and sediment load in the Zhujiang (Pearl River) Basin, China

    NASA Astrophysics Data System (ADS)

    Zhang, Shurong; Lu, Xi Xi; Higgitt, David L.; Chen, Chen-Tung Arthur; Han, Jingtai; Sun, Huiguo

    2008-02-01

    The paper is concerned with identifying changes in the time series of water and sediment discharge of the Zhujiang (Pearl River), China. The gradual trend test (Mann-Kendall test), and abrupt change test (Pettitt test), have been employed on annual water discharge and sediment load series (from the 1950s-2004) at nine stations in the main channels and main tributaries of the Zhujiang. Both the Mann-Kendall and Pettitt tests indicate that water discharge at all stations in the Zhujiang Basin showed no significant trend or abrupt shift. Annual water discharges are mainly influenced by precipitation variability, while the construction of reservoirs/dams in the Zhujiang Basin had little influence on water discharge. Sediment load, however, showed significant decreasing trends at some stations in the main channel of the Xijiang and Dongjiang. More stations have seen significantly decreasing trends since the 1990s. The decreasing sediment load in the Zhujiang reflects the impacts of reservoir construction in the basin. In contrast, the Liujiang, the second largest tributary of the Xijiang, has experienced a significant upward shift of sediment load around 1991 likely caused by exacerbated rock desertification in the karst regions. The annual sediment load from the Zhujiang (excluding the delta region) to the estuary has declined from 80.4 × 10 6 t averaged for the period 1957-1995 to 54.0 × 10 6 t for the period 1996-2004. More specifically, the sediment load declined steadily since the early 1990s so that in 2004 it was about one-third of the mean level of pre-90s. Water discharge and sediment load of the Zhujiang would be more affected by human activities in the future with the further reservoir developments, especially the completion of the Datengxia hydroelectric project, and an intensification of the afforestation policy in the drainage basin.

  7. Short and long term sediment flux in an inner-alpine sedimentary basin (Hohe Tauern, Austria)

    NASA Astrophysics Data System (ADS)

    Götz, Joachim; Schrott, Lothar

    2015-04-01

    Combined analyses of short and long term sediment fluxes in mountain environments have been rarely carried out until now. However, the relation of integrated postglacial landform volumes to single events (e.g. debris flows) provide the opportunity to establish meaningful frequency-magnitude-relationships, to evaluate present day geomorphic activity more reasonable, and to complement time series data typically covering only a short period of time. In this study we investigate recent and postglacial sediment flux in a small-scale denudation-accumulation system in the Hohe Tauern Range (Austrian Alps) using a complementary multi method approach including surface, subsurface and temporal analyses. We reconstructed the infill history and sedimentary architecture of the almost closed Gradenmoos basin, which has been filled up with sediments from different source areas delivered by mainly debris flows, rockfall and avalanche activity, and fluvial processes. In former times, glacial, glacio-fluvial and lacustrine sedimentation contributed to the basin fill as well. This process diversity led to a variety of interfingering and nested sediment storage landforms with a complex postglacial stratigraphy. Most important landforms include floodplain and peat bog deposits in the basin center as well as debris cones and talus sheets adjacent to the surrounding rockwalls. Postglacial basin sedimentation started after Younger Dryas deglaciation as indicated by radiocarbon ages of early-Holocene sediment core samples taken in the basin. For the following 7500 years, trap efficiency was maximised due to the presence of a former lake which is proved by morphometric, palynologic and stratigraphic data. Peat bog development finally began around 3500 years ago in the distal part of the basin. We interpolated the bedrock interface below the basin fill deposits using bedrock coordinates derived from core-drilling, geophysical prospection (electrical resistivity tomography, refraction seismic

  8. The legacy of lead (Pb) in fluvial bed sediments of an urban drainage basin, Oahu, Hawaii.

    PubMed

    Hotton, Veronica K; Sutherland, Ross A

    2016-03-01

    The study of fluvial bed sediments is essential for deciphering the impact of anthropogenic activities on water quality and drainage basin integrity. In this study, a systematic sampling design was employed to characterize the spatial variation of lead (Pb) concentrations in bed sediment of urban streams in the Palolo drainage basin, southeastern Oahu, Hawaii. Potentially bioavailable Pb was assessed with a dilute 0.5 N HCl extraction of the <63 μm grain-size fraction from the upper bed sediment layer of 169 samples from Palolo, Pukele, and Waiomao streams. Contamination of bed sediments was associated with the direct transport of legacy Pb from the leaded gasoline era to stream channels via a dense network of storm drains linked to road surfaces throughout the basin. The Palolo Stream had the highest median Pb concentration (134 mg/kg), and the greatest road and storm drain densities, the greatest population, and the most vehicle numbers. Lower median Pb concentrations were associated with the less impacted Pukele Stream (24 mg/kg), and Waiomao Stream (7 mg/kg). The median Pb enrichment ratio values followed the sequence of Palolo (68) > Pukele (19) > Waiomao (8). Comparisons to sediment quality guidelines and potential toxicity estimates using a logistic regression model (LRM) indicated a significant potential risk of Palolo Stream bed sediments to bottom-dwelling organisms. PMID:26573308

  9. Santa Barbara and Ventura basins: Tectonics, structure, sedimentation, oilfields along an east-west transect

    SciTech Connect

    Sylvester, A.G.; Brown, G.C.

    1988-01-01

    The Santa Barbara and Ventura basins are tectonically active and are economically important because millions of barrels of oil were produced there since the 1800s. This guidebook focuses on structural and sedimentological aspects of two main structural tends in the basin: the Rincon-Ventura anticlinorium, and the Oakridge-South Mountain uplift. Section One of the publication is a roadlog which summarizes geologic features. Section Two focuses on the sedimentation of the principal reservoirs and source rocks in the main oil fields in the two basins. Section Three presents four original papers on the oil fields and tectonic evolution of the area.

  10. Oblique-slip sedimentation and deformation in Nonacho basin (early Proterozoic), Northwest Territories, Canada

    SciTech Connect

    Aspler, L.B.; Donaldson, J.A.

    1984-04-01

    The Nonacho basin shares several traits with molassoid basins formed in oblique-slip settings: great thickness (about 9 km, 6 mi) of siliciclastic sediments deposited in alluvial fan, fan-delta, braided stream, beach, deltaic, and lacustrine environments; synsedimentary faults which activated nearby sources; rapid sedimentation and subsidence; telescoped facies transitions, particularly adjacent to active faults; extremely variable thickness of lithostratigraphic units; diachronous sedimentation resulting from the migration of source areas and sites of sedimentation along deformation fronts; mobility of deposition and deformation such that early sediments were uplifted, cannibalized, and redeposited; paleocurrents directed basinward near basin margins, and longitudinally in axial regions; lower greenschist facies metamorphism; paucity of volcanic rocks; and complicated structural geometries. However, these features alone are not diagnostic of qbique slip origin; all are compatible with rift, aulacogen, impactogen, retroarc, peripheral, intramontane, and broken foreland settings. More reliable indicators or an oblique-slip tectonic setting for the Nonacho basin are: anastomosing pattern of near-vertical, en echelon faults which delineate rhomb-, wedge, and rectangular-shaped semi-independent subbasins and basement uplifts; stretching lineations of shallow to moderate plunge along shear zones; folds and near-vertical penetrative fabrics, related to shear zones, but at angles of 20/sup 0/-30/sup 0/ to these zones. The Nonacho basin fill is interpreted as a foreland molasse of the Trans-Hudson orogene. Deposition and deformation probably occurred in response to convergence accommodated by oblique slip, analogous to the Tarim and Tsaidam basins of China, which developed in the late stages of India-Eurasia collision, north of the Tibetan Plateau.

  11. Sediment transport by streams in the Walla Walla basin, Washington and Oregon, July 1962-June 1965

    USGS Publications Warehouse

    Mapes, B.E.

    1969-01-01

    The Walla Walla River basin covers about 1,760 square miles in southeastern Washington and northeastern Oregon. From the 6,000-foot crest of the Blue Mountains on the east to the 340-foot altitude of Lake Wallula (Columbia River) on the west, the basin is drained by the Touchet River and Dry Creek, entirely within Washington, and by Mill Creek, North and South Forks Walla Walla River, and Pine Creek-Dry Creek, which all head in Oregon. The central lowland of the basin is bordered on the north by Eureka Flat, Touchet slope, and Skyrocket Hills, on the east by the Blue Mountains, and on the south by the Horse Heaven Hills. The basin is underlain by basalt of the Columbia River Group, which .is the only consolidated rock to crop out in the region. Various unconsolidated fluviatile, lacustrine, and eolian sediments cover the basalt. In the western part of the basin the basalt is overlain by lacustrine deposits of silt and sand which in places are mantled by varying thicknesses of loessal deposits. In the northern and central parts of the basin the loess is at least 100 feet thick. The mountainous eastern part of the basin is underlain at shallow depth by basalt which has a residual soil mantle weathered from the rock. The slopes of the mountains are characterized by alluvial fans and deeply cut stream valleys ,filled with alluvium of sand, gravel, and cobbles. Average annual precipitation in the basin ranges from less than 10 inches in the desert-like areas of the west to more than 45 inches in the timbered mountains of the east; 65 percent of the precipitation occurs from October through March. The average runoff from the basin is about 4.8 inches per year. Most of the runoff occurs during late winter and early spring. Exceptionally high runoff generally results from rainfall and rapid melting of snow on partially frozen ground. During the study period, July 1964-June 1965, average annual sediment yields in the basin ranged from 420 tons per square mile in the

  12. Assessing Suspended-Sediment Transport Rates at the Regional Scale: Lake Tahoe Basin

    NASA Astrophysics Data System (ADS)

    Heins, A.; Simon, A.

    2003-12-01

    In recent years, suspended-sediment transport has received increased attention due to a greater emphasis being placed on water quality issues. Secchi-disk data has shown a trend of decreasing water clarity in Lake Tahoe over the past 35 years that can be partly attributed to delivery of fine sediment from channel and upland sources. In an effort to quantify the magnitude and sources of suspended sediment into Lake Tahoe, the USDA-ARS National Sedimentation Laboratory with support from the U.S. Army Corps of Engineers initiated a study to examine these issues. Historical flow and sediment-transport data from more than 30 gages were used to determine bulk suspended-sediment loads and yields for sites around the lake. Eighteen index stations were used to make comparisons between sediment production and delivery from individual watersheds and between different sides of the lake. Fine-grained sediment transport was determined for 20 sites based on relations derived from particle-size distributions across the range of measured flows. Suspended-sediment loads and yields vary over orders of magnitude from year to year, from west to east and north to south across the basin. Median annual suspended-sediment loads for index stations range from about 2200 tonnes/yr (T/y) from the Upper Truckee River to 3 T/y from Logan House Creek. Based on the historical data, the largest annual contributors of sediment are in decreasing order, Upper Truckee River (2200 T/y), Blackwood Creek (1930 T/y), Second Creek (1410 T/y), Trout Creek (1190 T/y), Third Creek (880 T/y) and Ward Creek (855 T/y). Data from Second and Third Creeks may be somewhat misleading though because of a short period of data collection in the case of the former, and the fact that data collection occurred during major construction activities and following storm-induced debris flows in these basins. Analysis of suspended-sediment transport ratings with longer periods of record show that sediment loads from northeastern

  13. Simulation of contaminated sediment transport in White Oak Creek basin

    SciTech Connect

    Bao, Y.; Clapp, R.B.; Brenkert, A.L.; Moore, T.D.; Fontaine, T.A.

    1995-12-31

    This paper presents a systematic approach to management of the contaminated sediments in the White Oak Creek watershed at Oak Ridge National Laboratory near Oak Ridge, Tennessee. The primary contaminant of concern is radioactive cesium-137 ({sup 137}Cs), which binds to soil and sediment particles. The key components in the approach include an intensive sampling and monitoring system for flood events; modeling of hydrological processes, sediment transport, and contaminant flux movement; and a decision framework with a detailed human health risk analysis. Emphasis is placed on modeling of watershed rainfall-runoff and contaminated sediment transport during flooding periods using the Hydrologic Simulation Program- Fortran (HSPF) model. Because a large number of parameters are required in HSPF modeling, the major effort in the modeling process is the calibration of model parameters to make simulation results and measured values agree as closely as possible. An optimization model incorporating the concepts of an expert system was developed to improve calibration results and efficiency. Over a five-year simulation period, the simulated flows match the observed values well. Simulated total amount of sediment loads at various locations during storms match with the observed values within a factor of 1.5. Simulated annual releases of {sup 137}Cs off-site locations match the data within a factor of 2 for the five-year period. The comprehensive modeling approach can provide a valuable tool for decision makers to quantitatively analyze sediment erosion, deposition, and transport; exposure risk related to radionuclides in contaminated sediment; and various management strategies.

  14. Estimation of sediment sources using selected chemical tracers in the Perry lake basin, Kansas, USA

    USGS Publications Warehouse

    Juracek, K.E.; Ziegler, A.C.

    2009-01-01

    The ability to achieve meaningful decreases in sediment loads to reservoirs requires a determination of the relative importance of sediment sources within the contributing basins. In an investigation of sources of fine-grained sediment (clay and silt) within the Perry Lake Basin in northeast Kansas, representative samples of channel-bank sources, surface-soil sources (cropland and grassland), and reservoir bottom sediment were collected, chemically analyzed, and compared. The samples were sieved to isolate the <63 ?? m fraction and analyzed for selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, and the radionuclide cesium-137 (137Cs). On the basis of substantial and consistent compositional differences among the source types, total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), and 137Cs were selected for use in the estimation of sediment sources. To further account for differences in particle-size composition between the sources and the reservoir bottom sediment, constituent ratio and clay-normalization techniques were used. Computed ratios included TOC to TN, TOC to TP, and TN to TP. Constituent concentrations (TN, TP, TOC) and activities (137Cs) were normalized by dividing by the percentage of clay. Thus, the sediment-source estimations involved the use of seven sediment-source indicators. Within the Perry Lake Basin, the consensus of the seven indicators was that both channel-bank and surface-soil sources were important in the Atchison County Lake and Banner Creek Reservoir subbasins, whereas channel-bank sources were dominant in the Mission Lake subbasin. On the sole basis of 137Cs activity, surface-soil sources contributed the most fine-grained sediment to Atchison County Lake, and channel-bank sources contributed the most fine-grained sediment to Banner Creek Reservoir and Mission Lake. Both the seven-indicator consensus and 137Cs indicated that channel-bank sources were dominant for

  15. Role of river bank erosion in sediment budgets of catchments within the Loire river basin (France)

    NASA Astrophysics Data System (ADS)

    Gay, Aurore; Cerdan, Olivier; Poisvert, Cecile; Landemaine, Valentin

    2014-05-01

    Quantifying volumes of sediments produced on hillslopes or in channels and transported or stored within river systems is necessary to establish sediment budgets. If research efforts on hillslope erosion processes have led to a relatively good understanding and quantification of local sources, in-channel processes remain poorly understood and quasi inexistent in global budgets. However, profound landuse changes and agricultural practices have altered river functioning, caused river bank instability and stream incision. During the past decades in France, river channelization has been perfomed extensively to allow for new agricultural practices to take place. Starting from a recent study on the quantification of sediment fluxes for catchments within the Loire river basin (Gay et al. 2013), our aim is to complete sediment budgets by taking into account various sources and sinks both on hillslope and within channel. The emphasis of this study is on river bank erosion and how bank erosion contributes to global budgets. A model of bank retreat is developed for the entire Loire river basin. In general, our results show that bank retreat is on average quite low with approximately 1 cm.yr-1. However, a strong variability exists within the study area with channels displaying values of bank retreat up to ~10 cm.yr-1. Our results corroborate those found by Landemaine et al. in 2013 on a small agricultural catchment. From this first step, quantification of volumes of sediment eroded from banks and available for transport should be calculated and integrated in sediment budgets to allow for a better understanding of basin functioning. Gay A., Cerdan O., Delmas M., Desmet M., Variability of sediment yields in the Loire river basin (France): the role of small scale catchments (under review). Landemaine V., Gay A., Cerdan O., Salvador-Blanes S., Rodriguez S. Recent morphological evolution of a headwater stream in agricultural context after channelization in the Ligoire river (France

  16. Synthesis of nutrient and sediment data for watersheds within the Chesapaeake Bay drainage basin

    USGS Publications Warehouse

    Langland, M.J.; Lietman, P.L.; Hoffman, S.A.

    1995-01-01

    Nutrient and sediment data collected by Federal and state agencies from 1972 through 1992 at 1,058 surface-water sites in nontidal parts of the Chesapeake Bay Basin were compiled into a large database. Adequate nutrient, sediment, and streamflow data were not available to compute annual loads for all sites because water-quality monitoring at many of the sites was either short term or noncontinuous or because stream-flow was not measured. Annual nutrient and sediment loads were calculated at a total of 127 sites. Annual loads of dissolved nitrate were calculated for 108 sites, but total nitrogen loads could be calculated for only 48 of these sites because ammonia plus organic nitrogen data were not available for many of these 108 sites. Annual loads of total phosphorus were calculated for 99 sites, and annual loads of suspended sediment were calculated for 33 sites. Loads could be calculated for only a very few sites in the Juniata River Basin (a tributary to the Susquehanna River), the York River Basin, the middle and lower reaches of the James River, and the nontidal parts of the eastern shore of the Bay. Geographic Information System (GIS) spatial data sets of land use, physiographic province, rock type, and watershed delineation were compiled for the entire Chesapeake Bay Basin (approximately 64,000 square miles). The nutrient- and sediment-yield were evaluated with respect to land use, physiographic province, rock type, and hydrologic characteristics. During years that the mean streamflow was about equal to the long-term mean streamflow, the Susquehanna River contributed about 50 percent of the freshwater, 66 percent of the total nitrogen, and 40 percent of the total phosphorus transported by tributaries to the Bay. Nutrient and sediment data were available for less than 18 percent of the predominantly agricultural areas underlain by siliciclastic rock and for less than 35 percent of the predominantly agricultural areas underlain by either carbonate rock or

  17. Recent trends in sediment load of the tropical (Peninsular) river basins of India

    NASA Astrophysics Data System (ADS)

    Panda, Dileep K.; Kumar, A.; Mohanty, S.

    2011-02-01

    The tropical river basins of India are important because of the coastal ecosystem that they sustain and the densely populated economic zones that they serve. This study examines the recent trends in sediment load and also explores the influence of the climatic and human forcing mechanisms on the land-ocean fluvial systems. A large dataset comprised of the sediment time series of different timescale during the period 1986-87 to 2005-06 from 133 gauging stations spreading across tropical river basins of India was analyzed. Results indicate dramatic reductions in sediment load in the tropical river basins, which is beyond the fold of assignable natural variability. Around 88% (62%) of the total 133 gauging stations showed decline in sediment loads in the monsoon (non-monsoon) season. The significant downward trends outnumbered the corresponding upward trends in high proportions for both the seasons. Striking spatial coherence was observed among the significant trends, suggesting the presence of the cross-correlation among the sediment records. The regional trends, which account the spatial correlation, also indicated the widespread nature of the sediment declines. The rainfall, which is characterized by the non-significant decreasing trends and also frequent drought years, is the primary controller of the sediment loads for most of the river basins. It may be inferred that a little change in rainfall towards the deficit side leads to a significant reduction in sediment load. This is due to the diversion and storage of runoff to meet the manifold increases in water requirements for the agriculture and industry. Among the tropical rivers, the maximum reduction in sediment flux has taken place for the Normada River (-2.07 × 10 6 t/yr) due to the construction of dam. Although the sea level is rising, we speculate that the significant reduction in sediment loads may also have influenced the coastal erosion in recent years. The results of this study can be utilized for the

  18. An investigation of element ratios for assessing suspended-sediment sources in small agricultural basins

    USGS Publications Warehouse

    Juracek, K.

    2012-01-01

    Various sediment properties previously have been investigated for the purpose of determining sources of suspended sediment. A remaining research need is an assessment of element ratios for the determination of suspended-sediment sources in different terrestrial environments. In this study, 253 element ratios were assessed to determine which, if any, were potentially useful for sediment-source determinations in six small agricultural basins in northeastern Kansas, USA. Samples of surface soils (cropland and grassland), channel banks, and reservoir bottom sediments were collected, analyzed for 23 elements, and compared. Of the 253 element ratios assessed, only the Co/Pb and Co/Zn ratios were substantially and consistently different between the channel banks and surface soils for all six basins. For three of four reservoirs for which data were available, sediment-source estimates provided by Co/Pb ratios were in agreement with estimates previously provided using 137Cs. For two of the four reservoirs, sediment-source estimates provided by Co/Zn ratios were consistent with the 137Cs estimates. Thus, the Co/Pb ratio potentially may be more useful. Additional research is needed to ascertain whether or not the use of Co/Pb and Co/Zn ratios as tracers is widely applicable or restricted to specific terrestrial environments.

  19. Cascadia Basin Sediments as a Source for the North Pacific Silica Plume

    NASA Astrophysics Data System (ADS)

    Johnson, H. P.; Hautala, S. L.; Hammond, D. E.; Bjorklund, T. A.; Evans, R.; Esther, T.; Engstrom, P.; Worsnopp, M.; Lagerloef, M.; Kevin, J.; Penton, R.; Paukert, A.; Chung, E.; Schwartz, R.; Morello, A.

    2006-12-01

    The North Pacific silica plume extends from the North American margin almost to Siberia at an approximate mid-water depth of 2300 meters, and may be the largest single chemical anomaly in the global ocean. The plume contains 164 Teramols of silica and is sustained by a flux equivalent to one third of the total riverine silica input (1.5 Tmol/year) into the oceans. Cascadia Basin source estimates are 15-35 percent of the total flux that sustains the plume. A cruise in August 2006 examined potential source regions for dissolved silica within the small Cascadia/Gorda Basins adjacent to the Oregon/Washington/BC margins. During this cruise, 43 CTD and Niskin bottle casts, 11 sediment multi-core stations and 17 heat flow probe measurements were made. Water column samples for Rn-222 and Ra-228 were also taken to estimate vertical mixing rates and residence times. Sampling strategy focused on profiles within topographic 'gateways' that control entrance/egress of near-bottom water to/from the topographically restricted Cascadia/Gorda Basins. Sediment multi-core and heat flow stations were located to provide broad geographic coverage of the two Basins. Benthic fluxes of Si were estimated from core incubations and pore water profiles. Bottom water from the deep North Pacific enters into the Gorda/Cascadia Basins via the southern Mendocino/Gorda gateway with silica concentrations near 185 micromol/L, enriched by 20 micromol/L from the passage over the 4000 m deep western flank of the Juan de Fuca Ridge. Spatial distribution of dissolved silica within Cascadia Basin is non-uniform, with two large areas showing concentrations in excess of 200 micromol/L. These two areas include the western mid-Basin region and a N-S elongated area near, but not directly adjacent to, the OR/WA/BC continental margin. The two high concentration regions are divided by a tongue of cold and relatively low silica water that enters the Basin from the south through Cascadia Channel. The new data suggests

  20. Historical trends in organochlorine compounds in river basins identified using sediment cores from reservoirs

    USGS Publications Warehouse

    Van Metre, P.C.; Callender, E.; Fuller, C.C.

    1997-01-01

    This study used chemical analyses of dated sediment cores from reservoirs to define historical trends in water quality in the influent river basins. This work applies techniques from paleolimnology to reservoirs, and in the process, highlights differences between sediment-core interpretations for reservoirs and natural lakes. Sediment cores were collected from six reservoirs in the central and southeastern United States, sectioned, and analyzed for 137Cs and organochlorine compounds. 137Cs analyses were used to demonstrate limited post-depositional mixing, to indicate sediment deposition dates, and to estimate sediment focusing factors. Relative lack of mixing, high sedimentation rates, and high focusing factors distinguish reservoir sediment cores from cores collected in natural lakes. Temporal trends in concentrations of PCBs, total DDT (DDT + DDD + DDE), and chlordane reflect historical use and regulation of these compounds and differences in land use between reservoir drainages. PCB and total DDT core burdens, normalized for sediment focusing, greatly exceed reported cumulative regional atmospheric fallout of PCBs and total DDT estimated using cores from peat hogs and natural lakes, indicating the dominance of fluvial inputs of both groups of compounds to the reservoirs.This study used chemical analyses of dated sediment cores from reservoirs to define historical trends in water quality in the influent river basins. This work applies techniques from paleolimnology to reservoirs, and in the process, highlights differences between sediment-core interpretations for reservoirs and natural lakes. Sediment cores were collected from six reservoirs in the central and southeastern United States, sectioned, and analyzed for 137Cs and organochlorine compounds. 137Cs analyses were used to demonstrate limited post-depositional mixing, to indicate sediment deposition dates, and to estimate sediment focusing factors. Relative lack of mixing, high sedimentation rates, and high

  1. Hydrocarbon gas in sediment from the shelf, slope and basin of the Bering Sea.

    USGS Publications Warehouse

    Kvenvolden, K.A.; Redden, G.D.

    1980-01-01

    Methane, ethane, ethene, propane, propene, isobutane and n-butane are present in low concentrations in the top 2m of sediment. Methane is most abundant and its concentration increases with depth in the sediment. Ethane, ethene, propane and propene are present in almost all samples, but the concentrations of these gases are about two orders of magnitude-lower than the concentration of methane. The average ratios of ethane to ethene are usually greater than one in shelf sediment, about one in slope sediment, and usually less than one in basin sediments. These hydrocarbon gases are probably derived from low-temperature chemical and biochemical processes operating at or near the sea-floor. -from Authors

  2. Characterization of Channel Morphology and Sediment Loads for the Yazoo River Basin, Mississippi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The main purpose of this report was to provide the Mississippi Department of Environmental Quality (MDEQ) with geomorphic evaluations of previously visited biological sampling locations and update ‘reference’ suspended-sediment transport conditions within the Yazoo River Basin. This information wou...

  3. Tectonic Evolution of the Northern Malawi rift, East Africa: Structural Controls on Sediment Dispersal in a Large Lake Basin.

    NASA Astrophysics Data System (ADS)

    Mortimer, E.; Paton, D.; Scholz, C.; Strecker, M.

    2005-12-01

    The Malawi Rift is an integral part of the East African Rift system (EARs), the type example of a rift system in its youthful stages of development. Understanding the spatio-temporal evolution of this rift system provides insights into the past histories and controls on more ancient rift basins. Fundamental questions remain regarding the structural styles, partitioning, and sediment dispersal patterns within large lacustrine basins that are common to young rifts. Such basins are particularly useful recorders of climatic fluctuations. In areas with pronounced climatic variability and high evaporation/precipitation ratios this may lead to, often transient, basin isolation that may dramatically affect sediment and facies distribution. We investigate the structural evolution and sedimentation patterns of the North basin, Malawi Rift. We utilise two seismic reflection data sets: the first, collected by project PROBE, records the entire basin-fill (Sequences 1-3) at medium resolution; the second provides a closely-spaced high-resolution survey of the past ~1 Ma (Sequence 3). These data document the development of the basin-bounding and intra-basin faults. Throughout its history, the basin-bounding fault has accommodated the greatest strain and therefore exerted the fundamental control on the distribution of sediment within the rift. Present-day sediments enter the basin axially, although there is evidence that transverse supply was also important in the past. We identify 11 intra-basin structures that strike parallel or sub-parallel to this border fault. These intra-basin faults, active from the earliest stages, have initial segment lengths of ~30 km, but rapidly reach lengths in excess of 80 km in the north of the basin, and 60 km in the south. Much of the sedimentation along the faults occurred during Sequence 2 (~2.7-1.6 Ma), a period of relative over-filling of the basin. While the basin-bounding fault controls the overall sediment architecture, all 11 intra-basin

  4. Late Miocene and Pliocene synorogenic sedimentation in northern Livermore basin, California

    SciTech Connect

    Isaacson, K.A.; Andersen, D.W.

    1987-05-01

    Late Tertiary synorogenic sedimentation in the northern Livermore basin, Contra Costa County, California, has recorded two major changes in provenance. Changes in clast composition of fluvial conglomerates reflect regional tectonic reorganization as the San Andreas fault system began to evolve at this latitude. Shallow marine deposition of Sierran andesitic sediment gave way at approximately 8 Ma to fluvially dominated deposition of sediment from a local, graywacke-rich, Coast Range source. Deposition of reworked andesitic material prior to 5.5 Ma records development of anticlinal uplifts along trends of the present Altamont Hills and Calaveras fault system. By 4 Ma, the areal extent of the subsiding basin had increased; the Altamont Hills continued to be uplifted, but the Calaveras fault region began to subside rapidly. Late Miocene and Pliocene deformation of the Livermore basin area extended over a broad zone east of the developing transform fault system. Structures that developed included broad synclinal basins and gentle anticlinal uplifts that had topographic expression but were not deeply incised. Intense deformation of the basin and uplift of Mount Diablo occurred after 3 Ma.

  5. Application of Sediment Backstripping Corrections for Basin Analysis Using Microcomputers.

    ERIC Educational Resources Information Center

    Wilkerson, Marlon Scott; Hsui, Albert Tong-Kwan

    1989-01-01

    Discussed is a program created to serve as an instructional tool for teaching basin analysis. Described is the use of the program for interpreting plots resulting from backstripping methods. Included in the discussion are implementation, applications and availability of the "Subside!" program. (CW)

  6. Sediment Transportation Induced by Deep-Seated Landslides in a Debris Flow Basin in Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Meei Ling; Chen, Te Wei; Chen, Yong Sheng; Sin Jhuang, Han

    2016-04-01

    Typhoon Morakot brought huge amount of rainfall to the southern Taiwan in 2009 and caused severe landslides and debris flow hazard. After Typhoon Morakot, it was found that the volume of sediment transported by the debris flow and its effects on the affected area were much more significant compared to previous case history, which may due to the huge amount of rainfall causing significant deep-seated landslides in the basin. In this study, the effects and tendency of the sediment transportation in a river basin following deep-seated landslides caused by typhoon Morakot were evaluated. We used LiDAR, DEM, and aerial photo to identify characteristics of deep-seated landslides in a debris flow river basin, KSDF079 in Liuoguey District, Kaohsiung City, Taiwan. Eight deep-seated landslides were identified in the basin. To estimate the potential landslide volume associated with the deep-seated landslides, the stability analysis was conducted to locate the critical sliding surface, and the potential landside volume was estimated based on the estimation equation proposed by the International Geotechnical Societies' UNESCO Working Party on World Landslide Inventory (WP/WLI, 1990). The total potential landslide volume of the eight deep-seated landslides in KSDF079 basin was about 28,906,856 m3. Topographic analysis was performed by using DEM before and LiDAR derived DEM after typhoon Morakot to calculate the landslide volume transported. The result of erosion volume and deposition volume lead to a run out volume of 5,832,433 m3. The results appeared to consist well with the field condition and aerial photo. Comparing the potential landslide volume and run out volume of eight deep-seated landslides, it was found that the remaining potential landslide volume was about 80%. Field investigation and topographic analysis of the KSDF079 debris flow revealed that a significant amount of sediment deposition remained in the river channel ranging from the middle to the downstream

  7. Arsenic associations in sediments from shallow aquifers of northwestern Hetao Basin, Inner Mongolia

    USGS Publications Warehouse

    Deng, Y.; Wang, Y.; Ma, T.; Yang, H.; He, J.

    2011-01-01

    Understanding the mechanism of arsenic mobilization from sediments to groundwater is important for water quality management in areas of endemic arsenic poisoning, such as the Hetao Basin in Inner Mongolia, northern China. Aquifer geochemistry was characterized at three field sites (SH, HF, TYS) in Hangjinhouqi County of northwestern Hetao Basin. The results of bulk geochemistry analysis of sediment samples indicated that total As concentrations have a range of 6. 8-58. 5 mg/kg, with a median of 14. 4 mg/kg. The highest As concentrations were found at 15-25 m depth. In the meanwhile, the range of As concentration in the sediments from background borehole is 3-21. 8 mg/kg, with a median value of 9 mg/kg. The As sediments concentrations with depth from the SH borehole were correlated with the contents of Fe, Sb, B, V, total C and total S. Generally, the abundance of elements varied with grain size, with higher concentrations in finer fractions of the sediments. Distinct lithology profile and different geochemical characteristics of aquifer sediments indicate the sediments are associated with different sources and diverse sedimentary environments. Up to one third of arsenic in the sediments could be extracted by ammonium oxalate, suggesting that Fe oxyhydroxides may be the major sink of As in the aquifer. Sequential extraction results indicate that arsenic occurs as strongly adsorbed on and/or co-precipitated with amorphous Fe oxyhydroxides in sediments accounting for 35 and 20%, respectively, of the total contents of arsenic. The release of As into groundwater may occur by desorption from the mineral surface driven by reductive dissolution of the Fe oxide minerals. Furthermore, small proportions of As associated with iron sulfides occur in the reductive sediments. ?? 2011 Springer-Verlag.

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

    NASA Astrophysics Data System (ADS)

    Olabode, Solomon Ojo

    2014-01-01

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

  9. Carbon dioxide production in surface sediments of temporarily anoxic basins (Baltic Sea) and resulting sediment-water interface fluxes

    NASA Astrophysics Data System (ADS)

    Böttcher, M. E.; Al-Raei, A. M.; Winde, V.; Lenz, C.; Dellwig, O.; Leipe, T.; Segl, M.; Struck, U.

    2009-04-01

    Organic matter is mineralized in marine sediments by microbial activity using predominantly oxygen, sulfate, and metal oxides as electron acceptors. Modern euxinic basins as found in the Baltic Sea or the Black Sea are of particular importance because they may serve as type systems for anoxia in Earth's history. We present here results from biogeochemical investigations carried out in the Baltic deeps (Gotland Basin, Landsort Deep) during the first scientific cruise of RV M.S. MERIAN in 2006, additionally during RV Prof. Penck cruises in 2006 and 2007. Short sediment cores were obtained with a multi-corer and analyzed for particulate and dissolved main, minor and trace elements, pH, DIC, methane alkalinity, besides the stable carbon isotopes of dissolved inorganic carbon (DIC). Microsensors were applied to analyze steep gradients of oxygen, sulphide and sulphate. Pore water profiles are evaluated in terms of process rates and associated element fluxes using the PROFILE software (Berg et al., 1998, L&O). Gross and net anaerobic mineralization rates were additionally obtained from core incubations with 35S. Steep gradients in DIC are associated with a strong enrichment of the light stable isotope resulting in the Gotland basin from oxidized OM. Element fluxes across the sediment-water interface are compared with literature data and show for the Baltic Sea a dependence from bottom water redox conditions, and sediment compositions and formation conditions (e.g., accumulation rates). DIC in the anoxic part of the water column in the Landsort Deep and the Gotland Deep show relatively similar isotope values, close to the bottom water value, but steep gradients towards heavier values above the pelagic redoxcline. Acknowledgements: The research was supported by Leibniz IO Warnemünde, DFG (Cruise RV MSM MERIAN 01), and MPG. Thanks to B. Schneider and F. Pollehne stimulating discussions, and S. Lage and A. Schipper for technical support.

  10. Suspended-sediment characteristics for the Johnson Creek basin, Oregon, water years 2007-10

    USGS Publications Warehouse

    Stonewall, Adam J.; Bragg, Heather M.

    2012-01-01

    Significant Findings An analysis of suspended-sediment transport in the Johnson Creek basin, Oregon, during water years 2007–10 indicated that: Streamflow characteristics for the 4 years of study were not extremely dry or wet, and represented near-average conditions. Computed average annual suspended-sediment loads were 1,890 and 4,640 tons at the Gresham and Milwaukie stations, respectively. More than 70 percent of suspended-sediment transport in the watershed occurred during the high-flow months of November, December, and January. Less than 10 percent of suspended-sediment transport in the watershed occurred during April–October. About 50 percent of all suspended-sediment load is transported during the highest 1 percent of streamflows. The January 2009 streamflow peak was the third highest in the 70-year record for Johnson Creek. About 50 percent of suspended-sediment transport in water year 2009 occurred in January. The drainage area upstream of the Gresham streamflow-gaging station constitutes about 30 percent of the drainage area at the Milwaukie station, but accounted for about 40 percent of the suspended sediment and 45 percent of the streamflow at the Milwaukie station. On an annual basis, most of the higher sediment yield at the Gresham station, relative to the Milwaukie station, can be explained by the higher streamflow yield at the Gresham station rather than by higher suspended-sediment concentration.

  11. Water and Sediment Quality in the Yukon River Basin, Alaska, During Water Year 2001

    USGS Publications Warehouse

    Schuster, Paul F.

    2003-01-01

    Overview -- This report contains water-quality and sediment-quality data from samples collected in the Yukon River Basin during water year 2001 (October 2000 through September 2001). A broad range of chemical and biological analyses from three sets of samples are presented. First, samples were collected throughout the year at five stations in the basin (three on the mainstem Yukon River, one each on the Tanana and Porcupine Rivers). Second, fecal indicators were measured on samples from drinking-water supplies collected near four villages. Third, sediment cores from five lakes throughout the Yukon Basin were sampled to reconstruct historic trends in the atmospheric deposition of trace elements and hydrophobic organic compounds.

  12. Initial Sediment Transport Model of the Mining-Affected Aries River Basin, Romania

    USGS Publications Warehouse

    Friedel, Michael J.; Linard, Joshua I.

    2008-01-01

    The Romanian government is interested in understanding the effects of existing and future mining activities on long-term dispersal, storage, and remobilization of sediment-associated metals. An initial Soil and Water Assessment Tool (SWAT) model was prepared using available data to evaluate hypothetical failure of the Valea Sesei tailings dam at the Rosia Poieni mine in the Aries River basin. Using the available data, the initial Aries River Basin SWAT model could not be manually calibrated to accurately reproduce monthly streamflow values observed at the Turda gage station. The poor simulation of the monthly streamflow is attributed to spatially limited soil and precipitation data, limited constraint information due to spatially and temporally limited streamflow measurements, and in ability to obtain optimal parameter values when using a manual calibration process. Suggestions to improve the Aries River basin sediment transport model include accounting for heterogeneity in model input, a two-tier nonlinear calibration strategy, and analysis of uncertainty in predictions.

  13. Sediment delivery processes and the spatial distribution of caesium-137 in a small Sicilian basin

    NASA Astrophysics Data System (ADS)

    Ferro, Vito; di Stefano, Costanza; Giordano, Giuseppe; Rizzo, Salvatore

    1998-04-01

    The sediment delivery processes occurring in a small Sicilian basin are modelled using the spatially distributed SEDD model recently proposed by Ferro and Minacapilli. The model is applied by using soil data (grain-size distribution, organic matter content, etc.) of 129 samples uniformly distributed over the study area and compiling the available information (topographic map, soil data, etc.) into a Geographical Information System. Finally, the predictive capability of the distributed sediment delivery approach is tested experimentally using the caesium-137 measurement technique. The comparison between calculated sediment yield and the corresponding measured caesium-137 loss is used to validate the SEDD model at the scale of both the single morphological unit and the entire basin.

  14. Mass transport-dominated sedimentation in a foreland basin, the Hidaka Trough, northern Japan

    NASA Astrophysics Data System (ADS)

    Noda, Atsushi; TuZino, Taqumi; Joshima, Masato; Goto, Shusaku

    2013-08-01

    Mass transport is an important process of sediment redistribution from shallow to deep sea basins. It is vital to understand this process for disaster prevention and protection of economic interests in coastal and offshore areas. We describe mass transport-dominated sedimentation in an active foreland basin, the Hidaka Trough, which developed from collision between the northeastern Japan arc and the Kuril arc. The basin is deformed by east-west compression associated with large, frequent earthquakes. The trough is filled with thick (>4.5 km) sediments, ranging from coal-bearing Cretaceous terrestrial strata to modern diatomaceous hemipelagic mud and volcanic ash. Bottom-simulating reflectors and the distribution of mud volcanoes, pockmarks, and acoustic wipe-out zones on the seismic records suggest the presence of subsurface gases in the sediments. The basin features stacked mass transport deposits (MTDs), but no channel-levee systems have developed. The MTDs are relatively thin (<30 m) and are derived from three sides of the basin margin. Initiation of submarine slope failure in this area may be controlled by multiple factors that increase driving forces and decrease resistance of the slopes. The driving forces include oversteepening of the margin slope as a resul`t of thrusting and folding, and additional downslope gravitational acceleration caused by cyclic shaking during earthquakes. Decreased resistance in the slopes may be caused by the accumulation of excess pore-water pressure driven by a high-sedimentation rate, gas hydrate dissociation accompanying changes in sea level or seawater temperature, and liquefaction in coarse-grained beds during earthquakes.

  15. Eustatic and tectonic control of sedimentation in the Pennsylvanian strata of the Central Appalachian Basin

    SciTech Connect

    Chesnut, D.R. Jr. . Kentucky Geological Survey)

    1992-01-01

    Analysis of the Breathitt Group of the Central Appalachian Basin reveals three orders of depositional cycles or trends. The Breathitt coarsening-upward trend (20 million years (my)) represents increasing intensity of the Alleghenian Orogeny. The major transgression (MT) cycle (2.5 my) was controlled by an unknown eustatic or tectonic mechanism. The major coal beds and intervening strata make up the coal-clastic cycle (CC cycle) (=Appalachian cyclothem) which has a 0.4 my periodicity. This periodicity supports eustatic control of sedimentation modulated by an orbital periodicity. Extensive coastal peats deposited at lowstand (CC cycle) were preserved as coals, whereas highstand peats were eroded during the subsequent drop in sea level. Autocyclic processes such as delta switching and avulsion occurred within CC cycles. An Early Pennsylvanian unconformity represents uplift and erosion of mid-Carboniferous foreland basin deposits. Alluvial deposits (Breathitt Group) derived from the highlands were transported to the northwest toward the forebulge. During lowstand, the only outlet available to further sediment transport (Lee sandstones) was toward the southwest (Ouachita Trough), along the Black Warrior-Appalachian foreland basins. The Middle Pennsylvanian marks a period of intermittent overfilling of the foreland basin and cresting of the forebulge. Marine transgressions entered through the foreland basins and across saddles in the forebulge. After the Ouachita Trough was destroyed during the late Middle Pennsylvanian, marine transgressions migrated only across saddles in the forebulge. In the Late Pennsylvanian, marine waters entered the basin only across the diminished forebulge north of the Jessamine Dome.

  16. Channel morphometry, sediment transport, and implications for tectonic activity and surficial ages of Titan basins

    USGS Publications Warehouse

    Cartwright, R.; Clayton, J.A.; Kirk, R.L.

    2011-01-01

    Fluvial features on Titan and drainage basins on Earth are remarkably similar despite differences in gravity and surface composition. We determined network bifurcation (Rb) ratios for five Titan and three terrestrial analog basins. Tectonically-modified Earth basins have Rb values greater than the expected range (3.0-5.0) for dendritic networks; comparisons with Rb values determined for Titan basins, in conjunction with similarities in network patterns, suggest that portions of Titan's north polar region are modified by tectonic forces. Sufficient elevation data existed to calculate bed slope and potential fluvial sediment transport rates in at least one Titan basin, indicating that 75mm water ice grains (observed at the Huygens landing site) should be readily entrained given sufficient flow depths of liquid hydrocarbons. Volumetric sediment transport estimates suggest that ???6700-10,000 Titan years (???2.0-3.0??105 Earth years) are required to erode this basin to its minimum relief (assuming constant 1m and 1.5m flows); these lowering rates increase to ???27,000-41,000 Titan years (???8.0-12.0??105 Earth years) when flows in the north polar region are restricted to summer months. ?? 2011 Elsevier Inc.

  17. An evaluation of selenium concentrations in water, sediment, invertebrates, and fish from the Solomon River Basin

    USGS Publications Warehouse

    May, T.W.; Fairchild, J.F.; Petty, J.D.; Walther, M.J.; Lucero, J.; Delvaux, M.; Manring, J.; Armbruster, M.

    2008-01-01

    The Solomon River Basin is located in north-central Kansas in an area underlain by marine geologic shales. Selenium is an indigenous constituent of these shales and is readily leached into the surrounding groundwater. Portions of the Basin are irrigated primarily through the pumping of selenium-contaminated groundwater from wells onto fields in agricultural production. Water, sediment, macroinvertebrates, and fish were collected from various sites in the Basin in 1998 and analyzed for selenium. Selenium concentrations were analyzed spatially and temporally and compared to reported selenium toxic effect thresholds for specific ecosystem components: water, sediments, food-chain organisms, and wholebody fish. A selenium aquatic hazard assessment for the Basin was determined based on protocol established by Lemly. Throughout the Basin, water, macroinvertebrate, and whole fish samples exceeded levels suspected of causing reproductive impairment in fish. Population structures of several fish species implied that successful reproduction was occurring; however, the influence of immigration of fish from low-selenium habitats could not be discounted. Site-specific fish reproduction studies are needed to determine the true impact of selenium on fishery resources in the Basin. ?? Springer Science+Business Media B.V. 2007.

  18. Tectonically controlled sedimentation in the Mesozoic basins of the Antarctic Peninsula

    SciTech Connect

    MacDonald, D.I.M.; Butterworth, P.J. )

    1990-05-01

    The Antarctica Peninsula (AP) lies on a medium-size block of continental crust and is one of a mosaic of west Antarctica coastal block that underwent a complex tectonic evolution during Gondwana breakup. The peninsula represents the eroded roots of a microcontinental volcanic arc; this arc lay above the easterly subducting proto-Pacific plate, and was active throughout the Mesozoic. The exposed Mesozoic basins display a complex stratigraphy, reflecting local tectonic and volcanic events. There are a few general trends. Almost all basins are post-late Oxfordian, their fill is entirely clastic, and is largely derived from the Antarctica peninsula volcanic arc. Most basins were affected by a period of arc expansion in the latest Jurassic or earliest Cretaceous, which manifests itself as inputs of lava or coarse volcaniclastic sediment overlying mudstones with an open marine fauna. Barriasian and older mudstones are generally finer grained and darker than mudstones from post-Berriasian strata. However, it must be emphasized that these are only general trends. Deformation is variable, commonly progressive. No lithostratigraphic units can be correlated between any two basins, nor are there any interregional unconformities. No matching is possible with basins of equivalent age in formerly contiguous areas of Gondwana. There is evidence that some global eustatic events are recorded in the sedimentary records of at least two of the AP Mesozoic basins, but these have effect only in periods of local tectonic quiescence. The dominant control on sedimentation in this large segment of the Pacific rim was arc tectonics.

  19. Sediment transport by streams in the Palouse River basin, Washington and Idaho, July 1961-June 1965

    USGS Publications Warehouse

    Boucher, P.R.

    1970-01-01

    The Palouse River basin covers about 3,300 square miles in southeastern Washington and northwestern Idaho. The eastern part of the basin is composed of steptoes and foothills which are generally above an altitude of 2,600 feet; the central part is of moderate local relief and is mantled chiefly by thick loess deposits; and the western part is characterized by low relief and scabland topography and is underlain mostly by basalt. Precipitation increases eastward across the study area. It ranges annually from 12 to 18 inches in the western part and from 14 to 23 inches in the central part, and it exceeds 40 inches in the eastern part. Surface runoff from the basin for the 4-year period of study (July 1961-June 1965) averaged 408,000 acre-feet per year, compared with 445,200 acre-feet per year for the 27-year period of record. The eastern part of the basin contributed about 55 percent of the total, whereas the central and western parts contributed 37 percent and 8 percent, respectively. Most sediment transport from the Palouse River basin and the highest sediment concentrations in streams occurred in the winter. Of the several storms during the study period, those of February 3-9, 1963, December 22-27, 1964, and January 27-February 4, 1965, accounted for 81 percent of the total 4-year suspended-sediment load; the storm of February 3-9, 1963, accounted for nearly one-half the total load. The discharge-weighted mean concentration of suspended sediment carried in the Palouse River past Hooper during the study period was 2,970 milligrams per liter. The average annual sediment discharge of the Palouse River at its mouth was about 1,580,000 tons per year, and the estimated average annual sediment yield was 480 tons per square mile. The yield ranged from 5 tons per square mile from the western part of the basin to 2,100 tons per square mile from the central part. The high yield from the central part is attributed to a scarcity of vegetal cover, to the fine-grained loess soils

  20. When sink becomes source: Importance of sediment recycling in linked orogen-basin systems

    NASA Astrophysics Data System (ADS)

    Romans, Brian W.; Fosdick, Julie C.; Hubbards, Stephen M.; Fildani, Andrea

    2013-04-01

    Much of the recent research on sedimentary system dynamics has focused on extant systems where the linkage of sediment production from eroding highlands can be directly linked to deposition in lowlands and/or offshore basins. Studies of such systems, typically late Pleistocene to Holocene in age, are especially valuable for quantitative constraints such as system morphometrics (e.g., longitudinal profiles, basin volumes, etc.) and rates of processes (e.g., erosion/denudation, sediment accumulation, etc.), which can be measured directly or estimated with relatively high certainty. Moreover, information about climate and tectonic forcings that are independent to the system is explicitly known for extant systems. However, an understanding of longer-term (>105 yr) evolution can only be gained through the investigation of ancient systems. Such systems are either buried in the subsurface, which requires geophysical remote sensing and/or drilling, or exposed at the Earth's surface as outcrops as the result of uplift and exhumation. The dynamic linkage of mountain belt and adjacent basin makes foreland basin systems ideal natural laboratories to address long-term sedimentary system evolution. In this presentation, we highlight important issues and challenges that sedimentary systems research is currently facing, with an emphasis on sediment recycling during progressive stages of basin development. In this context, we focus on sedimentary systems in which multiple episodes of uplift and erosion of the primary depocenter led to a history whereby basin material was repeatedly recycled. The spatial and temporal aspects of sediment recycling have implications for how provenance signals (based on composition, crystallization or metamorphic age information, thermal history, etc.) are used. Additionally, improved constraints regarding the timescales and magnitude of sediment recycling have implications for system-scale modeling. Key parameters such as total sediment volumes and

  1. Sediment discharge from an area of highway construction, Applemans Run basin, Columbia County, Pennsylvania

    USGS Publications Warehouse

    Eckhardt, David A.

    1976-01-01

    The effects of highway construction on stream sediment loads were studied in Applemans Run basin, Columbia County, Pa., from October 1971 to May 1974. During the investigations, about 5,200 tons of suspended-sediment were discharged from the basin. Of this amount, about 2,700 tons, or about half the total sediment discharge, as derived from the highway construction area. Annual suspended-sediment yields from 17.5 acres under construction ranged from 40,000 to 66,000 tons/sq mi in the 1972 and 1973 water years, respectively. In the 1972 and 1973 er years of active construction, 83 percent of the sediment transported from the construction site was eroded each year in storms from January to June. Seasonal trends in sediment discharge for 1972 show that 69 percent of that year 's suspended-load was transported in April, May, and June, whereas less than 1 percent was transported in July, August, and September. (Woodard-USGS)

  2. Paleomagnetic secular variation as an intra-basinal and extra-basinal correlation tool for Pleistocene lake sediments

    SciTech Connect

    Negrini, R.M.; Erbes, D.B. . Dept. of Physics and Geology); Roberts, A.P.; Verosub, K.L.

    1993-04-01

    High-resolution age control is a serious problem encountered by those studying middle to late Pleistocene lake sediments, especially saline lake deposits which commonly are low in organic content obviating the use of bulk sediment radiocarbon dating. Paleomagnetic secular variation, the low amplitude variation in the direction and intensity of the Earth's magnetic field, can be recorded accurately in lake sediments. In this case if offers a high-resolution correlation tool which can be used for intra- and extra-basinal correlations. In principal, this could extend geographically as far away as marine environments enabling on to tie non-marine stratigraphy into the well-dated chronology common to marine sediment records. Examples are given of correlations based on this technique. The examples, in turn, are based on ongoing paleomagnetic and lithostratigraphic studies in the sediments of Pleistocene Lakes Chewaucan, Lahontan and previously-published paleomagnetic records from Pleistocene Lake Russell and from two un-named Pleistocene lakes. Intrabasinal correlations in Lake Chewaucan support the contention that secular variation can be used to correlate outcrop exposures (three samples per horizon) on a depth scale of several centimeters which probably corresponds to a temporal resolution of a few hundred years or less.

  3. Mercury in bottom sediment and aquatic invertebrates, Carson and Truckee River Basins, Nevada and California

    SciTech Connect

    Lawrence, S.J.; Bevans, H.E.

    1994-12-31

    Bottom sediment and aquatic invertebrates were sampled for trace-element analyses at 11 sites in the Carson and Truckee River Basins during September 1 992 as part of the US Geological Survey`s National Water-Quality Assessment Program. Composite bottom-sediment samples from inundated depositional areas were wet-sieved through a 63-micrometer nylon mesh and composite aquatic invertebrate samples were allowed to depurate prior to analyses. In the Carson River Basin, mercury concentrations increased downstream from 0.24 microgram per gram, dry weight ({mu}g/g), in both bottom sediment and western crayfish (Pacifastacus leniusculus) samples from the East Fork Carson River near Markleeville, Calif., to 5.9 {mu}g/g in bottom sediment in the Carson River near Fallon, Nev., and to 48 {mu}g/g in western crayfish in the river near Fort Churchill, Nev. Asiatic clams (Corbicula fluminea) from the Carson River at Fort Churchill and near Fallon had 6.1 and 1.4 {mu}g/g of mercury, respectively. In the Truckee River Basin, mercury concentrations increased downstream from 0.02 {mu}g/g in bottom sediment and 0.17--0.21 {mu}g/g in western crayfish at sites upstream of Reno, Nev., to 0.58 {mu}g/g in bottom sediment and 0.49 {mu}g/g in western crayfish at Clark, Nev. Downstream patterns of mercury concentration in bottom sediment and western crayfish are similar. Possible sources of mercury include historical gold and silver ore-milling activities, acid mine drainage, mineral deposits, and urban activities.

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

    USGS Publications Warehouse

    Wu, Yping; Chen, Ji

    2012-01-01

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

  5. Lead exposure of waterfowl ingesting Coeur d?Alene River Basin sediments

    USGS Publications Warehouse

    Beyer, W.N.; Audet, D.J.; Morton, Alexandra; Campbell, J.K.; LeCaptain, L.

    1998-01-01

    Feces from tundra swans (Cygnus columbianus [Ord]), Canada geese (Branta canadensis [L.]) and mallards (Anas platyrhynchos [L.]) were collected from the Coeur d?Alene River Basin and two reference areas to estimate exposure to lead from mining activities and to relate that exposure to the ingestion of contaminated sediments. The average acid-insoluble ash content of the feces, a measure of sediment, was 18% for Canada geese and tundra swans, and 12% for ducks. The 18% value corresponded to an estimated 9% sediment ingestion rate (dry weight). The 90th percentile for acid-insoluble ash in feces of tundra swans corresponds to an estimated 22% sediment in the diet. The average lead concentration (dry weight) of tundra swan feces from all Coeur d?Alene River Basin wetlands sampled was 880 mg/kg, compared to 2.1 mg kg1 from reference wetlands. The 90th percentile of lead in tundra swan feces from the Coeur d?Alene River Basin sites was 2700 mg kg1. Fecal lead concentrations of tundra swans from Harrison Slough, the wetland studied in most detail, were correlated (Spearman?s rho = 0.74, p < 0.05) with the acid-insoluble ash content of the feces. The very low lead concentrations in feces having low acid-insoluble ash contents established that the sediment was the primary source of the lead ingested by waterfowl. Sediment lead concentrations at 11 wetland sites were closely correlated (r = 0.91, p < 0.05) with average fecal lead concentrations for all waterfowl, corrected for the average percent acid-insoluble ash in the feces. The regression equation describing this relation, along with estimates of sediment ingestion, provides a straight-forward means of estimating the current exposure of waterfowl to lead and of predicting the potential exposure of waterfowl to lead under plans to clean up the contaminated sites.

  6. Sediment yield and runoff frequency of small drainage basins in the Mojave Desert, U.S.A.

    NASA Astrophysics Data System (ADS)

    Griffiths, Peter G.; Hereford, Richard; Webb, Robert H.

    2006-03-01

    Sediment yield from small arid basins, particularly in the Mojave Desert, is largely unknown owing to the ephemeral nature of these fluvial systems and long recurrence interval of flow events. We examined 27 reservoirs in the northern and eastern Mojave Desert that trapped sediment from small (< 1 km 2) drainage basins on alluvial fans over the past 100 yr, calculated annual sediment yield, and estimated the average recurrence interval (RI) of sediment-depositing flow events. These reservoirs formed where railbeds crossed and blocked channels, causing sediment to be trapped and stored upslope. Deposits are temporally constrained by the date of railway construction (1906-1910), the presence of 137Cs in the reservoir profile (post-1952 sediment), and either 1993, when some basins breached during regional flooding, or 2000-2001, when stratigraphic analyses were performed. Reservoir deposits are well stratified at most sites and have distinct fining-upward couplets indicative of discrete episodes of sediment-bearing runoff. Average RI of runoff events for these basins ranges from 2.6 to 7.3 yr and reflects the incidence of either intense or prolonged rainfall; more than half the runoff events occurred before 1963. A period of above-normal precipitation, from 1905 to 1941, may have increased runoff frequency in these basins. Mean sediment yield (9 to 48 tons km - 2 yr - 1 ) is an order of magnitude smaller than sediment yields calculated elsewhere and may be limited by reduced storm intensity, the presence of desert pavement, and shallow gradient of fan surfaces. Sediment yield decreases as drainage area increases, a trend typical of much larger drainage basins where sediment-transport processes constrain sediment yield. Coarse substrate and low-angle slopes of these alluvial fan surfaces likely limit sediment transport capacity through transmission losses and channel storage.

  7. Sediment yield and runoff frequency of small drainage basins in the Mojave Desert, U.S.A

    USGS Publications Warehouse

    Griffiths, P.G.; Hereford, R.; Webb, R.H.

    2006-01-01

    Sediment yield from small arid basins, particularly in the Mojave Desert, is largely unknown owing to the ephemeral nature of these fluvial systems and long recurrence interval of flow events. We examined 27 reservoirs in the northern and eastern Mojave Desert that trapped sediment from small (< 1 km2) drainage basins on alluvial fans over the past 100 yr, calculated annual sediment yield, and estimated the average recurrence interval (RI) of sediment-depositing flow events. These reservoirs formed where railbeds crossed and blocked channels, causing sediment to be trapped and stored upslope. Deposits are temporally constrained by the date of railway construction (1906-1910), the presence of 137Cs in the reservoir profile (post-1952 sediment), and either 1993, when some basins breached during regional flooding, or 2000-2001, when stratigraphic analyses were performed. Reservoir deposits are well stratified at most sites and have distinct fining-upward couplets indicative of discrete episodes of sediment-bearing runoff. Average RI of runoff events for these basins ranges from 2.6 to 7.3 yr and reflects the incidence of either intense or prolonged rainfall; more than half the runoff events occurred before 1963. A period of above-normal precipitation, from 1905 to 1941, may have increased runoff frequency in these basins. Mean sediment yield (9 to 48 tons km-2 yr-1) is an order of magnitude smaller than sediment yields calculated elsewhere and may be limited by reduced storm intensity, the presence of desert pavement, and shallow gradient of fan surfaces. Sediment yield decreases as drainage area increases, a trend typical of much larger drainage basins where sediment-transport processes constrain sediment yield. Coarse substrate and low-angle slopes of these alluvial fan surfaces likely limit sediment transport capacity through transmission losses and channel storage. ?? 2005 Elsevier B.V. All rights reserved.

  8. Assessing sedimentation rates at Usumacinta and Grijalva river basin (Southern Mexico) using OSL and suspended sediment load analysis: A study from the Maya Classic Period

    NASA Astrophysics Data System (ADS)

    Munoz-Salinas, E.; Castillo, M.; Sanderson, D.; Kinnaird, T.; Cruz-Zaragoza, E.

    2013-12-01

    Studying sedimentation rates on floodplains is key to understanding environmental changes occurred through time in river basins. The Usumacinta and Grijalva rivers flow most of their travel through the southern part of Mexico, forming a large river basin, crossing the states of Chiapas and Tabasco. The Usumacinta-Grijalva River Basin is within the 10 major rivers of North America, having a basin area of ~112 550 km2. We use the OSL technique for dating two sediment profiles and for obtaining luminescence signals in several sediment profiles located in the streambanks of the main trunk of the Usumacinta and Grijalva rivers. We also use mean annual values of suspended sediment load spanning ~50 years to calculate the sedimentation rates. Our OSL dating results start from the 4th Century, when the Maya Civilization was at its peak during the Classic Period. Sedimentation rates show a notable increase at the end of the 19th Century. The increase of the sedimentation rates seems to be related to changes in land uses in the Sierra Madre de Chiapas and Altos de Chiapas, based on deforestation and land clearing for developing new agrarian and pastoral activities. We conclude that the major environmental change in the basin of the Usumacinta and Grijalva Rivers since the Maya Classic Period was generated since the last Century as a result of an intense anthropogenic disturbance of mountain rain forest in Chiapas.

  9. Variability of suspended sediment yields within the Loire river basin (France)

    NASA Astrophysics Data System (ADS)

    Gay, A.; Cerdan, O.; Delmas, M.; Desmet, M.

    2014-11-01

    Suspended sediment fluxes and their variability in time and space have received much attention over the past decades. Large databases compiling suspended sediment load (SL) data are often used to serve these purposes. Analyses of these databases have highlighted the following two major limitations: (i) the role of lowland areas in sediment production and transfer has been minimised, and studies on small-scale catchments (with a drainage area of ⩽102 km2) are practically non-existent in the literature; and (ii) inhomogeneous data and calculation methods are used to estimate and compare the SL values. In this context, the present study aims to complete the existing studies by providing a reliable comparison of SL values for various catchments within lowland river basins. Therefore, we focused on the Loire and Brittany river basins (France). 111 small to large catchments covering 78% of this area and representative of the basins landscape diversity were chosen. We first present a large database of area-specific suspended sediment yields (SY) calculated from the suspended sediment concentration and flow discharge data over 7-40 yr of measurements at gauging stations. Two calculation methods are used, and the calculated loads are confined within a factor of 0.60-1.65 of the real values. Second, we analyse the temporal and spatial variability of the calculated SY values. Finally, using a nested catchment approach, we provide insight into sediment transport from upstream to downstream gauging stations and into the role of small- and medium- scale catchments in sediment production and transfers. The SL values at the outlet of the catchments range from 2.5 * 102 to 8.6 * 105 t yr-1, and the SY values range from 2.9 to 32.4 t km-2 yr-1. A comparison with the limited values available in the literature for this region corroborates our estimations. Sediment exports from the Loire and Brittany river basins are very low compared with mountainous regions and European exports

  10. The link between tectonics and sedimentation in back-arc basins: New genetic constraints from the analysis of the Pannonian Basin

    NASA Astrophysics Data System (ADS)

    Balázs, A.; Matenco, L.; Magyar, I.; Horváth, F.; Cloetingh, S.

    2016-06-01

    The architecture of sedimentary basins reflects the relationship between accommodation space and sediment supply, their rates and localization being variable during basin evolution. The mechanisms driving the interplay between tectonics and sedimentation in extensional back-arc basins overlying rheological weak zones inherited from an earlier orogenic evolution are less understood. A typical example is the Pannonian back-arc basin of Central Europe. It is floored by continental lithosphere and was affected by large amounts of extension driven by the subduction rollback that took place in the Carpathians and/or Dinarides. A novel kinematic and seismic sequence stratigraphic interpretation calibrated by wells allows the quantification of the link between the formation of half grabens and coeval sedimentation in the Great Hungarian Plain part of the basin. While the lower order tectonic-induced cycles characterize the main phases of extension in various subbasins, the higher-order cyclicity and associated unconformities define individual moments of fault (re)activation. Our novel interpretation of a temporal and spatial migration of extension during Miocene times explains the contrasting present-day strike of various subbasins as a result of their gradual clockwise rotation. Incorporating the observed asymmetry, in particular the associated footwall exhumation, infers that the amount of extension is much larger than previously thought. The quantitative link between tectonics and sedimentation has allowed the definition of a novel model of sedimentation in asymmetric basins that can be ported to other natural scenarios of similarly hyperextended back-arc basins observed elsewhere.

  11. Tectonic controls on sedimentation in Mesozoic convergent margin basin of Baja California (Mexico)

    SciTech Connect

    Busby-Spera, C.J.; Smith, D.P.; Morris, W.R. )

    1990-05-01

    Mesozoic rocks of the Baja California peninsula form one of the most extensive, best exposed, oldest (160 m.y.), and least-tectonized and metamorphosed convergent margin basin complexes in the world. Much of the fill of these basins consist of coarse-grained volcaniclastic and epiclastic sequences that directly reflect the tectonic evolution of the region. The early history of the convergent margin was dominated by sedimentation in small, steep-sided basins within oceanic island arc systems. The Triassic and Jurassic convergent margin basins probably represent proto-Pacific terranes that traveled from another area. These terranes were assembled by the Late Jurassic to Early Cretaceous, and underlie the forearc region of a medial Cretaceous oceanic island arc system. Tbis system fringed the Mesoamerican continental margin and underwent regional-scale extension during subduction of old, dense lithosphere. The latest phases of sedimentation in the convergent margin occurred in broad, relatively stable forearc basins of a mature continental arc, during the Late Cretaceous to Paleocene. Nonetheless, intrabasinal faults provided some controls on depositional systems and bathymetry. The authors speculate that these faults formed in response to oblique convergence which ultimately resulted in 10-19{degree} northward displacement of Baja California relative to the North American craton, from the latitude of Central America to northern Mexico. The fill of oceanic island arc basins in Baja California is dominated by coarse-grained marine wedges including (1) arc apron deposits, consisting of pyroclastic and/or volcanic epiclastic debris deposited in intra-arc or back-arc basins, and (2) slope apron deposits, consisting of epiclastic debris shed from local fault scarps and more distally derived arc volcaniclastics, deposited in forearc basins.

  12. Bacterial biogeography influenced by shelf-basin exchange in the Arctic surface sediment at the Chukchi Borderland.

    PubMed

    Han, Dukki; Nam, Seung-Il; Ha, Ho Kyung; Kim, Hyoungjun; Sadowsky, Michael J; Lee, Yoo Kyung; Hur, Hor-Gil

    2016-02-01

    It has been known that continental shelves around the Arctic Ocean play a major role in the ventilation of the deep basins as a consequence of shelf-basin exchange. In the present study, we found that bacterial assemblage of the surface sediment was different from that of seawater while seawater harboured local bacterial assemblages in response to the Arctic hydrography. This finding suggests that the Arctic seafloor sediments may have distinctive bacterial biogeography. Moreover, the distribution of bacterial assemblages and physicochemical properties in surface sediments changed gradually from the Arctic continental shelf to deep-sea basin. Based on the results, bacterial biogeography in the Arctic seafloor sediments may be influenced by winnowing and re-deposition of surface sediments through the sediment gravity flow. The present study offers a deeper understanding of shelf convection and its role for the construction of bacterial assemblages in the Arctic Ocean.

  13. Bacterial biogeography influenced by shelf-basin exchange in the Arctic surface sediment at the Chukchi Borderland.

    PubMed

    Han, Dukki; Nam, Seung-Il; Ha, Ho Kyung; Kim, Hyoungjun; Sadowsky, Michael J; Lee, Yoo Kyung; Hur, Hor-Gil

    2016-02-01

    It has been known that continental shelves around the Arctic Ocean play a major role in the ventilation of the deep basins as a consequence of shelf-basin exchange. In the present study, we found that bacterial assemblage of the surface sediment was different from that of seawater while seawater harboured local bacterial assemblages in response to the Arctic hydrography. This finding suggests that the Arctic seafloor sediments may have distinctive bacterial biogeography. Moreover, the distribution of bacterial assemblages and physicochemical properties in surface sediments changed gradually from the Arctic continental shelf to deep-sea basin. Based on the results, bacterial biogeography in the Arctic seafloor sediments may be influenced by winnowing and re-deposition of surface sediments through the sediment gravity flow. The present study offers a deeper understanding of shelf convection and its role for the construction of bacterial assemblages in the Arctic Ocean. PMID:26411339

  14. Integrative neural networks model for prediction of sediment rating curve parameters for ungauged basins

    NASA Astrophysics Data System (ADS)

    Atieh, M.; Mehltretter, S. L.; Gharabaghi, B.; Rudra, R.

    2015-12-01

    One of the most uncertain modeling tasks in hydrology is the prediction of ungauged stream sediment load and concentration statistics. This study presents integrated artificial neural networks (ANN) models for prediction of sediment rating curve parameters (rating curve coefficient α and rating curve exponent β) for ungauged basins. The ANN models integrate a comprehensive list of input parameters to improve the accuracy achieved; the input parameters used include: soil, land use, topographic, climatic, and hydrometric data sets. The ANN models were trained on the randomly selected 2/3 of the dataset of 94 gauged streams in Ontario, Canada and validated on the remaining 1/3. The developed models have high correlation coefficients of 0.92 and 0.86 for α and β, respectively. The ANN model for the rating coefficient α is directly proportional to rainfall erosivity factor, soil erodibility factor, and apportionment entropy disorder index, whereas it is inversely proportional to vegetation cover and mean annual snowfall. The ANN model for the rating exponent β is directly proportional to mean annual precipitation, the apportionment entropy disorder index, main channel slope, standard deviation of daily discharge, and inversely proportional to the fraction of basin area covered by wetlands and swamps. Sediment rating curves are essential tools for the calculation of sediment load, concentration-duration curve (CDC), and concentration-duration-frequency (CDF) analysis for more accurate assessment of water quality for ungauged basins.

  15. Temporal Variation of Streamflow, Sediment Load and Their Relationship in the Yellow River Basin, China

    PubMed Central

    Zhao, Guangju; Mu, Xingmin; Strehmel, Alex; Tian, Peng

    2014-01-01

    Variation of streamflow and sediment load in the Yellow River basin has received considerable attention due to its drastic reduction during the past several decades. This paper presents a detailed investigation on the changes of streamflow and sediment load from 1952 to 2011 using monthly observations at four gauging stations along the Yellow River. The results show significant decreasing trends for both streamflow and sediment load at all four gauging stations over the past 60 years. The wavelet transform demonstrated discontinuous periodicities from 1969 to 1973 and after 1986 due to the construction of large reservoirs and implementation of numerous soil and water conservations practices. The sediment rating curves with the power-law function was applied to investigate the relationship between discharge and sediment load. The results indicate distinct variations of the relationship between streamflow and sediment and implied significant hydro-morphological changes within different periods. The reducing sediment supply from the source region and the increased erosive power of the river are detected at Lanzhou station, while the decrease of the transport capacity at Toudaoguai is caused by severe siltation. Significant changes in the relationship between streamflow and sediment load are found at Huayuankou and Gaocun stations, which are largely induced by evident sediment income and trapping effects of large reservoirs. It is estimated that numerous reservoirs have strongly altered the regime and magnitude of streamflow and trapped large amount of sediment, leading to severe siltation and evident reduction of their total volumes. A decrease in precipitation, incoming water from the upper reaches, soil and water conservation measures as well as water consumption contribute most to the significant reduction of streamflow. The decrease of sediment load mainly resulted from various soil and water conservation measures and trapping in reservoirs from 1986 to 2011. PMID

  16. Temporal variation of streamflow, sediment load and their relationship in the Yellow River basin, China.

    PubMed

    Zhao, Guangju; Mu, Xingmin; Strehmel, Alex; Tian, Peng

    2014-01-01

    Variation of streamflow and sediment load in the Yellow River basin has received considerable attention due to its drastic reduction during the past several decades. This paper presents a detailed investigation on the changes of streamflow and sediment load from 1952 to 2011 using monthly observations at four gauging stations along the Yellow River. The results show significant decreasing trends for both streamflow and sediment load at all four gauging stations over the past 60 years. The wavelet transform demonstrated discontinuous periodicities from 1969 to 1973 and after 1986 due to the construction of large reservoirs and implementation of numerous soil and water conservations practices. The sediment rating curves with the power-law function was applied to investigate the relationship between discharge and sediment load. The results indicate distinct variations of the relationship between streamflow and sediment and implied significant hydro-morphological changes within different periods. The reducing sediment supply from the source region and the increased erosive power of the river are detected at Lanzhou station, while the decrease of the transport capacity at Toudaoguai is caused by severe siltation. Significant changes in the relationship between streamflow and sediment load are found at Huayuankou and Gaocun stations, which are largely induced by evident sediment income and trapping effects of large reservoirs. It is estimated that numerous reservoirs have strongly altered the regime and magnitude of streamflow and trapped large amount of sediment, leading to severe siltation and evident reduction of their total volumes. A decrease in precipitation, incoming water from the upper reaches, soil and water conservation measures as well as water consumption contribute most to the significant reduction of streamflow. The decrease of sediment load mainly resulted from various soil and water conservation measures and trapping in reservoirs from 1986 to 2011.

  17. Fluvial sediment study of Fishtrap and Dewey Lakes drainage basins, Kentucky - Virginia

    USGS Publications Warehouse

    Curtis, William F.; Flint, Russell F.; George, Frederick H.; Santos, John F.

    1978-01-01

    Fourteen drainage basins above Fishtrap and Dewey Lakes in the Levisa Fork and Johns Creek drainage basins of eastern Kentucky and southwestern Virginia were studied to determine sedimentation rates and origin of sediment entering the two lakes. The basins ranged in size from 1.68 to 297 square miles. Sediment yields ranged from 2,890 to 21,000 tons per square mile where surface-mining techniques predominated, and from 732 to 3 ,470 tons per square mile where underground mining methods predominated. Yields, in terms of tons per acre-foot of runoff, ranged from 2.2 to 15 for surface-mined areas, and from 0.5 to 2.7 for underground-mined areas. Water and sediment discharges from direct runoff during storms were compared for selected surface-mined and underground-mined areas. Data points of two extensively surface-mined areas, one from the current project and one from a previous project in Beaver Creek basin, McCreary County, Kentucky, grouped similarly in magnitude and by season. Disturbed areas from mining activities determined from aerial photographs reached 17 percent in one study area where extensive surface mining was being practiced. For most areas where underground mining was practiced, percentage disturbed area was almost negligible. Trap efficiency of Fishtrap Lake was 89 percent, and was 62 percent for Dewey Lake. Average annual deposition rates were 464 and 146 acre-feet for Fishtrap and Dewey Lakes, respectively. The chemical quality of water in the Levisa Fork basin has been altered by man 's activities. (Woodard-USGS)

  18. Latest Cretaceous-Paleogene basin development and resultant sedimentation patterns in the thrust belt and broken foreland of central Utah

    SciTech Connect

    Lawton, T.F. ); Franczyk, K.J.; Pitman, J.K. )

    1990-05-01

    Latest Cretaceous tectonism in central and east-central Utah formed several intermontane basins both atop thrust sheets and between the thrust front and basement-involved uplifts in the former foreland basin. The upper Campanian Castlegate Sandstone and its inferred western equivalents were the last strata deposited prior to segmentation of the foreland basin. Thereafter, eastward transport of the thrust allochthon uplifted the most proximal part of the Castlegate depositional wedge. West of the thrust front, small intermontane basins formed on the allochthon. Sediment was transported into these basins from both eastern and western sources. In each basin, facies grade from basin-margin conglomeratic alluvial fan deposits to basin-interior flood-plain and lacustrine deposits within a few kilometers. These intermontane basins existed from latest Campanian through the late Paleocene, and may have been transported a short distance eastward as they formed. East of the thrust front in the latest Campanian and contemporaneous with basin formation on the allochthon, a northward-northeastward-flowing big river system transported sediment into the foreland basin from feldspar-rich source areas southwest of the study area. Subsequently, major movement of the San Rafael uplift in the very late Campanian or early Maastrichtian gave rise to an intermontane basin between the thrust front and the San Rafael uplift. Northwestward-flowing, pebble-bearing braided rivers deposited the oldest sediments in this basin prior to an influx from the south and southwest of sediment that formed a thick Maastrichtian clastic sequence. In contrast to deposition in basins on the allochthon, deposition east of the thrust front in the Paleocene was intermittent and restricted to rapidly shifting centers of basin subsidence.

  19. 10Be-derived Himalayan denudation rates and sediment budgets in the Ganga basin

    NASA Astrophysics Data System (ADS)

    Lupker, Maarten; Blard, Pierre-Henri; Lavé, Jérôme; France-Lanord, Christian; Leanni, Laetitia; Puchol, Nicolas; Charreau, Julien; Bourlès, Didier

    2012-06-01

    The Himalayas represent the archetype of mountain building due to active continental collision and are considered in many studies as the locus of intense interactions between climate, denudation and tectonics. Estimates of modern denudation rates across the entire range remain, however, relatively sparse. In this study, in situ-produced cosmogenic 10Be concentrations were measured in detritic quartz in order to determine basin-scale denudation rates for the central part of the Himalayan range. River sand was sampled over several years in the main trans-Himalayan rivers, from the Himalayan front to the Ganga outlet in Bangladesh. The calculated 10Be denudation rates of the trans-Himalayan river basins range from 0.5 to 2.4 mm yr-1 (average 1.3 mm yr-1) and vary by up to a factor of 3 between sampling years. These denudation rates strongly contrast with the 0.007 mm yr-1 denudation rate of southern tributary basins draining the Indian craton. This work also shows that in the Ganga basin, no systematic evolution of average 10Be concentrations is observed during floodplain transfer, implying that distal samples can be used to estimate the integrated denudation rate of the whole central Himalayan range. Samples from the Ganga in Bangladesh display remarkably low variability in 10Be concentration, implying an average Himalayan denudation rate of 1.0-1.1 mm yr-1. However, within the floodplain, several samples suggest a recent perturbation of sediment transport dynamics with a recent increase in the relative sediment contribution from southern tributaries. The Himalayan sediment flux, deduced from the 10Be denudation rate of the range, is 610±230 Mt yr-1. This flux is consistent, within uncertainty, with sediment fluxes derived from sediment gauging. The similarity of the two flux estimates suggests that Himalayan erosion fluxes have remained stable over the last centuries, even if the large uncertainties associated with each method hamper more precise assessments.

  20. Provenance and Dispersal of Quaternary Sediments in the Gaxun Nur Basin, Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Schimpf, S.; Diekmann, B.; Hartmann, K.; Wuennemann, B.; Zhang, C.

    2013-12-01

    The Gaxun Nur Basin is an intramontane accumulation area with one of the biggest continental alluvial fans in the world. It is situated in the western part of Inner Mongolia and its origin is the result of the interplay between tectonic activity and climate dynamics. Due to the endorheic character of the basin, it is predestined as a terrestrial longtime-archive of climate and environmental change. The sediments in the Gaxun Nur basin were deposited during the last 250 kyr by the Hei River System with a catchment size of roughly 130.000 km2. To understand the sedimentary processes of this huge sediment cascade from the Qilian Mountains in the south to the terminal lakes in the north, sources of sediments have to be investigated. Sediment provenance can be deduced from mineralogical fingerprints of modern sediments deposited along the recent pathways from the sources (Qilian Mountains) to the sink (Gaxun Nur Basin). The resulting spatial variation serves as a reference for the mineralogical data from a drilling core in the distal part of the Gaxun Nur Basin. Inferring spatial and temporal variation of sediment provenance provides important information for reconstructing sediment input by fluvial, eolian, lacustrine, and glacial processes. The methodical approach focusses on the analysis of clay and heavy minerals, using XRD and petrographic techniques. Other methods involve geochemistry of heavy mineral grains, using computer-controlled scanning electron microscope (CCSEM), as well as bulk geochemistry, XRF element scanning and a statistical data processing. In this poster we present geochemical and mineralogical data of a 20 m long sediment core (GN100) combined with the results of about 200 surface sediment samples from different archives of the whole Hei River catchment. Lithological changes in the drilling core reveal temporal variations in the depositional environment. These variations are related to alternating phases of fluvial and eolian activity supported

  1. Development of sediment overpressure and its effect on thermal maturation: Application to the Gulf of Mexico basin

    SciTech Connect

    Mello, U.T.; Karner, G.D.

    1996-09-01

    High sedimentation rates can potentially lead to overpressuring and sediment undercompaction within basins. Sediments with anomalously high porosity, in turn, induce low thermal conductivities and so tend to act as a thermal insulator to the flow of heat. In the Gulf of Mexico basin (Gulf basin), the generation of overpressure is caused mainly by the inability of pore pressure fluids to escape at a rate commensurate with sedimentation. We modeled the generation and dissipation of abnormal sediment pore pressure due to variations in sedimentation rate, facies, formation porosity, and permeability within the Gulf basin using finite-element techniques to solve the differential equations of both heat and fluid transport within compacting sediments. We assume that the porosity-effective stress relationship within the sediment follows a negative exponential steady-state form when the pore pressure is hydrostatic. An important feature of our modeling approach is the assumption that sediments are incapable of significant expansion in response to increasing pore pressure. Sediments are assumed to hydrofracture when the pore pressure approaches the lithostatic pressure, rather than a common assumption of porosity expansion even in lithified sediments. From our modeling, we conclude that significant overpressures have been created (and dissipated) at various times within the Gulf basin and track, in general, the west to east migration of sediment loads deposited since the Cretaceous. Although predicted overpressures of more than 0.75 kpsi (i.e., an equivalent excess hydraulic head of 500 in) of Campanian-Maastrichtian age remain to the present day, the main phase of overpressure development in the Gulf basin is predicted to have occurred during the Miocene-Holocene. Maximum overpressures ({approximately}13.6 kpsi; excess hydraulic head of 9.4 km) are predicted for the present day.

  2. Three cycles of sedimentation in ancient sedimentary basins of southern Ireland: insights from detrital zircon U-Pb ages

    NASA Astrophysics Data System (ADS)

    Fairey, Brenton; Kerrison, Aidan; Meere, Patrick; Mulchrone, Kieran; Linnemann, Ulf; Hofmann, Mandy; Gaertner, Andreas; Sonntag, Benita-Lisette; Byrne, Keith

    2016-04-01

    Previous work has shown that sedimentary rocks from the Lower Devonian Dingle Basin were uplifted and recycled by Acadian orogenic activity into the Upper Devonian Munster Basin. This is particularly applicable for sediments deposited in the western part of the Munster Basin. In the present study, a new dataset of U-Pb ages for detrital zircons has been established that spans a large geographic area which includes the Dingle and Munster basins as well as the offshore Mesozoic North Celtic Sea, South Celtic Sea, 'Goban Spur' and Fastnet basins. The study is the first of its kind in any of these sedimentary basins. The aim is to investigate whether sediments deposited in the offshore basins during the Mesozoic reflect three erosion-deposition cycles. Detritus that has undergone three sedimentary cycles would yield super-mature sediments suitable for hydrocarbon storage. Detrital zircon age spectra for Lower Devonian Dingle Basin samples indicate strong sediment input from Avalonian (~600 Ma) and Laurentian (~1.7 Ga and ~1.1 Ga) sources with some input from Caledonian orogenic sources (400-480 Ma). Detrital zircon age spectra in the western Munster Basin largely reflect input from Caledonian-aged igneous crustal input (400-480 Ma) and Laurentian sources. An Avalonian component is not detected in any of the samples from the western Munster Basin. In the central and eastern parts of the Munster Basin, detrital zircon age spectra indicate that the dominant sources of detritus are derived from Laurentia and from Caledonian igneous rocks. In contrast to the western part of the basin, age components around 600 Ma are present in some samples and represent an Avalonian source. These signals are echoed, at varying degrees, in detrital age spectra from Jurassic and Cretaceous samples of the central North Celtic Sea Basin. These age spectra also indicate a significant contribution of detritus from Avalonian terrane. The Avalonian signature is completely absent from Jurassic

  3. New chronology for the southern Kalahari Group sediments - implications for sediment-cycle dynamics and basin development

    NASA Astrophysics Data System (ADS)

    Matmon, Ari; Hidy, Alan; Vainer, Shlomy; Crouvi, Onn; Fink, David; Erel, Yigal; Aster Team; Horwitz, Liora; Chazan, Michael

    2016-04-01

    Kalahari Group sediments accumulated in the Kalahari basin, which started forming during the breakup of Gondwana in the early Cretaceous. These sediments cover an extensive part of southern Africa and form a low-relief landscape. Current models assume that the Kalahari Group accumulated throughout the entire Cenozoic. However, chronology has been restricted to early-middle Cenozoic biostratigraphic correlations and to OSL dating of only the past ~300 ka. We present a new chronological framework that reveals a dynamic nature of sedimentation in the southern Kalahari. Cosmogenic burial ages obtained from a 55 m section of Kalahari Group sediments from the Mamatwan Mine, southern Kalahari, indicate that the majority of deposition at this location occurred rapidly at 1-1.2 Ma. This Pleistocene sequence overlies the Archaean basement, forming a significant hiatus that permits the possibility of many Phanerozoic cycles of deposition and erosion no longer preserved in the sedimentary record. Our data also establish the existence of a shallow early-middle Pleistocene water body that persisted for >450 ka prior to this rapid period of deposition and suggesting an Okavango-like environment. Evidence from neighboring archaeological excavations in southern Africa suggests an association of high-density hominin occupation with this water body.

  4. Spatial and Temporal Distribution of Polycyclic Aromatic Hydrocarbons and Heavy Metals in Stormwater Detention Basin Sediments

    NASA Astrophysics Data System (ADS)

    Schifman, L. A.; Kasaraneni, V. K.; Boving, T. B.; Craver, V.

    2015-12-01

    Stormwater runoff is a conduit for several pollutants such as polycyclic aromatic hydrocarbons (PAHs) into surface and ground water bodies. The control of runoff and pollutants is typically addressed by best management practices, such as retention/detention ponds. While the effectiveness of catchment basins in runoff volume reduction and removal of some contaminants has been established, very little is known about contaminant fate within these structures. Particularly in coastal regions and places with shallow groundwater tables PAH accumulation in the bottom sediments poses a potential threat for groundwater contamination. The concentrations of PAHs accumulated in the sediments of these catchment basins will primarily depend on the sources of runoff origin and the surrounding land use. Here, five stormwater catchment basins along the I-95 corridor in Rhode Island were selected based on the stormwater runoff origin and land use (industrial, urban, highway, and commercial). To study the stratification of PAHs one foot sediment cores were collected and analyzed for 17 PAHs (16 EPA parent PAH and Retene). The concentrations of PAHs in sediments of detention ponds in urban and industrial land use areas ranged from 20 μg/g to 200 μg/g. Generally higher concentrations of contaminants were found in sediments near the pond inlet and a decreasing concentration gradient is observed laterally and vertically throughout the pond. To compare stormwater ponds in various land use settings a new index based on sediment contamination, pond size and age, and catchment area will be presented. Further, it will be investigated whether BMP maintenance has to be targeted towards pollutant removal to maintain an effective stormwater treatment system.

  5. The Nordkapp Basin, Norway: Development of salt and sediment interplays for hydrocarbon exploration

    SciTech Connect

    Lerche, I.; Toerudbakken, B.O.

    1996-12-31

    Investigation of a particular salt diapir in the Nordkapp Basin, Barents Sea has revealed the following sequence of events: (1) salt started to rise when approximately 1.5 {+-} 0.3 km of sedimentary cover was present (Carboniferous/Permian time); (2) salt reached the sediment surface when about 3.5 {+-} 0.7 km of sediment had been deposited (Triassic time); (3) the mushroom cap on the salt stock top developed over a period of about 75--100 Ma (i.e. during the time when about another km of sediment had been deposited) (Triassic through Base Cretaceous time); (4) the mushroom cap started to dip down significantly ({approximately}1 km) into the sediments around Cretaceous to Tertiary erosion time; (5) oil generation started in the deep sediments of the Carboniferous around the time that salt reached the surface (Triassic time) and continues to the present day at sedimentary depths between about 4 to 7 km (currently Triassic and deeper sediments); (6)gas generation started around mushroom cap development time and continues to the present day at sedimentary depths greater than about 6--7 km (Permian/Carboniferous); (7) the salt stock is currently 3--4 km wide, considerably less than the mushroom cap which is 9 km wide and 1 km thick. The relative timing of mushroom cap development, bed upturning, and hydrocarbon generation makes the salt diapir an attractive exploration target, with suggested reservoir trapping under the downturned mushroom cap on the deep basin side of the salt. In addition, rough estimates of rim syncline fill suggest the basin had an original salt thickness of 2.4--3.3 km, depending upon the amount of salt removed at the Tertiary erosion event.

  6. Lead exposure of waterfowl ingesting Coeur d`Alene River Basin sediments

    SciTech Connect

    Beyer, W.N.; Morton, A.; Audet, D.J.; Campbell, J.K.; LeCaptain, L.

    1998-11-01

    Feces from tundra swans [Bygnus columbianus (Ord)], Canada geese [Branta canadensis (L.)], and mallards [Anas platrhynchos (L.)] were collected from the Coeur d`Alene River Basin and two reference areas in Idaho to estimate exposure to lead from mining activities and relate that exposure to the ingestion of contaminated sediments. The average acid-insoluble ash content of the feces, a measure of sediment ingestion, was 18% for Canada geese and tundra swans, and 12% for ducks. The 18% value corresponded to an estimated 9% sediment ingestion rate (dry weight). The 90th percentile for acid-insoluble ash in feces of tundra swans-corresponded to an estimated 22% sediment in the diet. The average lead concentration (dry weight) of tundra swan feces from all Coeur d`Alene River Basin wetlands sampled was 880 mg/kg, compared to 2.1 mg kg{sup {minus}1} from reference areas. the 90th percentile of lead in tundra swan feces from the Coeur d`Alene River Basin sites was 2700 mg kg{sup {minus}1}. Fecal lead concentrations of tundra swans were correlated with the acid-insoluble ash content of the feces. The very low lead concentrations in feces having low acid-insoluble ash contents established that the sediment was the primary source of the lead ingested by waterfowl. Sediment lead concentrations at 11 wetland sites were closely correlated with average fecal lead concentrations for all waterfowl, corrected for the average percent acid-insoluble ash in the feces.

  7. Microbial Communities in Methane- and Short Chain Alkane-Rich Hydrothermal Sediments of Guaymas Basin.

    PubMed

    Dowell, Frederick; Cardman, Zena; Dasarathy, Srishti; Kellermann, Matthias Y; Lipp, Julius S; Ruff, S Emil; Biddle, Jennifer F; McKay, Luke J; MacGregor, Barbara J; Lloyd, Karen G; Albert, Daniel B; Mendlovitz, Howard; Hinrichs, Kai-Uwe; Teske, Andreas

    2016-01-01

    The hydrothermal sediments of Guaymas Basin, an active spreading center in the Gulf of California (Mexico), are rich in porewater methane, short-chain alkanes, sulfate and sulfide, and provide a model system to explore habitat preferences of microorganisms, including sulfate-dependent, methane- and short chain alkane-oxidizing microbial communities. In this study, hot sediments (above 60°C) covered with sulfur-oxidizing microbial mats surrounding a hydrothermal mound (termed "Mat Mound") were characterized by porewater geochemistry of methane, C2-C6 short-chain alkanes, sulfate, sulfide, sulfate reduction rate measurements, in situ temperature gradients, bacterial and archaeal 16S rRNA gene clone libraries and V6 tag pyrosequencing. The most abundantly detected groups in the Mat mound sediments include anaerobic methane-oxidizing archaea of the ANME-1 lineage and its sister clade ANME-1Guaymas, the uncultured bacterial groups SEEP-SRB2 within the Deltaproteobacteria and the separately branching HotSeep-1 Group; these uncultured bacteria are candidates for sulfate-reducing alkane oxidation and for sulfate-reducing syntrophy with ANME archaea. The archaeal dataset indicates distinct habitat preferences for ANME-1, ANME-1-Guaymas, and ANME-2 archaea in Guaymas Basin hydrothermal sediments. The bacterial groups SEEP-SRB2 and HotSeep-1 co-occur with ANME-1 and ANME-1Guaymas in hydrothermally active sediments underneath microbial mats in Guaymas Basin. We propose the working hypothesis that this mixed bacterial and archaeal community catalyzes the oxidation of both methane and short-chain alkanes, and constitutes a microbial community signature that is characteristic for hydrothermal and/or cold seep sediments containing both substrates. PMID:26858698

  8. Microbial Communities in Methane- and Short Chain Alkane-Rich Hydrothermal Sediments of Guaymas Basin.

    PubMed

    Dowell, Frederick; Cardman, Zena; Dasarathy, Srishti; Kellermann, Matthias Y; Lipp, Julius S; Ruff, S Emil; Biddle, Jennifer F; McKay, Luke J; MacGregor, Barbara J; Lloyd, Karen G; Albert, Daniel B; Mendlovitz, Howard; Hinrichs, Kai-Uwe; Teske, Andreas

    2016-01-01

    The hydrothermal sediments of Guaymas Basin, an active spreading center in the Gulf of California (Mexico), are rich in porewater methane, short-chain alkanes, sulfate and sulfide, and provide a model system to explore habitat preferences of microorganisms, including sulfate-dependent, methane- and short chain alkane-oxidizing microbial communities. In this study, hot sediments (above 60°C) covered with sulfur-oxidizing microbial mats surrounding a hydrothermal mound (termed "Mat Mound") were characterized by porewater geochemistry of methane, C2-C6 short-chain alkanes, sulfate, sulfide, sulfate reduction rate measurements, in situ temperature gradients, bacterial and archaeal 16S rRNA gene clone libraries and V6 tag pyrosequencing. The most abundantly detected groups in the Mat mound sediments include anaerobic methane-oxidizing archaea of the ANME-1 lineage and its sister clade ANME-1Guaymas, the uncultured bacterial groups SEEP-SRB2 within the Deltaproteobacteria and the separately branching HotSeep-1 Group; these uncultured bacteria are candidates for sulfate-reducing alkane oxidation and for sulfate-reducing syntrophy with ANME archaea. The archaeal dataset indicates distinct habitat preferences for ANME-1, ANME-1-Guaymas, and ANME-2 archaea in Guaymas Basin hydrothermal sediments. The bacterial groups SEEP-SRB2 and HotSeep-1 co-occur with ANME-1 and ANME-1Guaymas in hydrothermally active sediments underneath microbial mats in Guaymas Basin. We propose the working hypothesis that this mixed bacterial and archaeal community catalyzes the oxidation of both methane and short-chain alkanes, and constitutes a microbial community signature that is characteristic for hydrothermal and/or cold seep sediments containing both substrates.

  9. Microbial Communities in Methane- and Short Chain Alkane-Rich Hydrothermal Sediments of Guaymas Basin

    PubMed Central

    Dowell, Frederick; Cardman, Zena; Dasarathy, Srishti; Kellermann, Matthias Y.; Lipp, Julius S.; Ruff, S. Emil; Biddle, Jennifer F.; McKay, Luke J.; MacGregor, Barbara J.; Lloyd, Karen G.; Albert, Daniel B.; Mendlovitz, Howard; Hinrichs, Kai-Uwe; Teske, Andreas

    2016-01-01

    The hydrothermal sediments of Guaymas Basin, an active spreading center in the Gulf of California (Mexico), are rich in porewater methane, short-chain alkanes, sulfate and sulfide, and provide a model system to explore habitat preferences of microorganisms, including sulfate-dependent, methane- and short chain alkane-oxidizing microbial communities. In this study, hot sediments (above 60°C) covered with sulfur-oxidizing microbial mats surrounding a hydrothermal mound (termed “Mat Mound”) were characterized by porewater geochemistry of methane, C2–C6 short-chain alkanes, sulfate, sulfide, sulfate reduction rate measurements, in situ temperature gradients, bacterial and archaeal 16S rRNA gene clone libraries and V6 tag pyrosequencing. The most abundantly detected groups in the Mat mound sediments include anaerobic methane-oxidizing archaea of the ANME-1 lineage and its sister clade ANME-1Guaymas, the uncultured bacterial groups SEEP-SRB2 within the Deltaproteobacteria and the separately branching HotSeep-1 Group; these uncultured bacteria are candidates for sulfate-reducing alkane oxidation and for sulfate-reducing syntrophy with ANME archaea. The archaeal dataset indicates distinct habitat preferences for ANME-1, ANME-1-Guaymas, and ANME-2 archaea in Guaymas Basin hydrothermal sediments. The bacterial groups SEEP-SRB2 and HotSeep-1 co-occur with ANME-1 and ANME-1Guaymas in hydrothermally active sediments underneath microbial mats in Guaymas Basin. We propose the working hypothesis that this mixed bacterial and archaeal community catalyzes the oxidation of both methane and short-chain alkanes, and constitutes a microbial community signature that is characteristic for hydrothermal and/or cold seep sediments containing both substrates. PMID:26858698

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  11. Manganese Oxidizing Bacteria in Guaymas Basin Hydrothermal Fluids, Sediments, and Plumes

    NASA Astrophysics Data System (ADS)

    Dick, G. J.; Tebo, B. M.

    2002-12-01

    The active seafloor hydrothermal system at Guaymas Basin in the Gulf of California is unique in that spreading centers are covered with thick sediments, and hydrothermal fluids are injected into a semi-enclosed basin. This hydrothermal activity is the source of a large input of dissolved manganese [Mn(II)] into Guaymas Basin, and the presence of a large standing stock of particulate manganese in this basin has been taken as evidence for a short residence time of dissolved Mn(II) with respect to oxidation, suggestive of bacterial catalysis. During a recent Atlantis/Alvin expedition (R/V Atlantis Cruise #7, Leg 11, Jim Cowen Chief Scientist), large amounts of particulate manganese oxides were again observed in Guaymas Basin hydrothermal plumes. The goal of the work presented here was to identify bacteria involved in the oxidation of Mn(II) in Guaymas Basin, and to determine what molecular mechanisms drive this process. Culture-based methods were employed to isolate Mn(II)-oxidizing bacteria from Guaymas Basin hydrothermal fluids, sediments, and plumes, and numerous Mn(II)-oxidizing bacteria were identified based on the formation of orange, brown, or black manganese oxides on bacterial colonies on agar plates. The Mn(II)-oxidizing bacteria were able to grow at temperatures from 12 to 50°C, and a selection of the isolates were chosen for phylogenetic (16S rRNA genes) and microscopic characterization. Endospore-forming Bacillus species accounted for many of the Mn(II)-oxidizing isolates obtained from both hydrothermal sediments and plumes, while members of the alpha- and gamma-proteobacteria were also found. Mn(II)-oxidizing enzymes from previously characterized Bacillus spores are known to be active at temperatures greater than 50°C. The presence of Mn(II)-oxidizing spores - some of which are capable of growing at elevated temperatures - in hydrothermal fluids and sediments at Guaymas Basin suggests that Mn(II) oxidation may be occurring immediately or very soon

  12. Turbidity and suspended-sediment transport in the Russian River Basin, California

    USGS Publications Warehouse

    Ritter, John R.; Brown, William M.

    1971-01-01

    The Russian River in north coastal California has a persistent turbidness, which has reportedly caused a decline in the success of the sports fishermen. As a consequence, the number of sports fishermen angling in the river has declined, and industries dependent on their business have suffered. To determine the source of the turbidity and the rate of sediment transport in the basin, a network of sampling station was established in February 1964 along the river, on some of its tributaries, and near Lake Pillsbury in the upper Eel River basin.

  13. Sediment flux history of Pearl River mouth basin, North margin of South China Sea

    NASA Astrophysics Data System (ADS)

    Wu, S.

    2004-12-01

    This work estimates the solid sediment flux in Pearl River mouth basin from Cenozoic (42Ma). The estimates were derived from isopach maps, seismic reflection profiles and drill holes. Average solid sediment fluxes were calculated for six epochs approximately corresponding to geological periods: Eocene-Lower Oligocene (42-29.3), Upper Oligocene (29.3-23.8), Lower Miocene (23.8-16.4), Middle Miocene (16.4-11.2), Upper Miocene (11.2-5.32), and Pliocene-Pleistocene (5.32-0). The total sediment flux from 42 Ma is 392071.3 km3 and 0.89 km of erosion formed from the onshore drainage basin area. The average erosion rate is 22 m/ Ma. The sediment flux curve shows 3 episodes massive increase in sediment supply, i.e. Upper Oligocene, Middle Miocene and Pliocene-Pleistocene. The first increase related to the break up activity and is the product of elevated rift shoulder. The other two increase peak link to the changing of climate.

  14. Differential arsenic binding in the sediments of two sites in Chile's lower Loa River basin.

    PubMed

    Bugueño, Manuel P; Acevedo, Sara E; Bonilla, Carlos A; Pizarro, Gonzalo E; Pasten, Pablo A

    2014-01-01

    Fluvial sediments from two lower Loa River basin sites in northern Chile were compared in order to probe the effects of vegetation and organic matter (OM) on As accumulation in fluvial environments. The two sites were the Sloman dam, which lacks macrophytes and has a low OM content (2.4%) in sediments, and the Quillagua Oasis, which is 23 km downstream from the Sloman site and has a higher OM (6.2%) in sediments and abundant aquatic plant life. The Quillagua site had preferential As enrichment with a co-occurrence pattern that differed from that of the Sloman site, which had a lower As concentration (1528 vs. 262 mg/kg d.w., respectively). At the Quillagua site, As concentration was strongly correlated with Mn and OM (r = 0.91 and 0.85, respectively); while at the Sloman site, As concentration in sediments was significantly correlated with Ca and Sr (r = 0.63 and 0.54, respectively). Sequential extraction analyses showed that the Sloman site had higher percentage of easily exchangeable As within the surface sediment (12%, 45 mg/kg d.w.) compared with the Quillagua site (3%, 40 mg/kg d.w.). These contrasting results suggest that both vegetation and OM control the immobilization and accumulation of As in the arid Loa River basin.

  15. Differential arsenic binding in the sediments of two sites in Chile's lower Loa River basin.

    PubMed

    Bugueño, Manuel P; Acevedo, Sara E; Bonilla, Carlos A; Pizarro, Gonzalo E; Pasten, Pablo A

    2014-01-01

    Fluvial sediments from two lower Loa River basin sites in northern Chile were compared in order to probe the effects of vegetation and organic matter (OM) on As accumulation in fluvial environments. The two sites were the Sloman dam, which lacks macrophytes and has a low OM content (2.4%) in sediments, and the Quillagua Oasis, which is 23 km downstream from the Sloman site and has a higher OM (6.2%) in sediments and abundant aquatic plant life. The Quillagua site had preferential As enrichment with a co-occurrence pattern that differed from that of the Sloman site, which had a lower As concentration (1528 vs. 262 mg/kg d.w., respectively). At the Quillagua site, As concentration was strongly correlated with Mn and OM (r = 0.91 and 0.85, respectively); while at the Sloman site, As concentration in sediments was significantly correlated with Ca and Sr (r = 0.63 and 0.54, respectively). Sequential extraction analyses showed that the Sloman site had higher percentage of easily exchangeable As within the surface sediment (12%, 45 mg/kg d.w.) compared with the Quillagua site (3%, 40 mg/kg d.w.). These contrasting results suggest that both vegetation and OM control the immobilization and accumulation of As in the arid Loa River basin. PMID:23933427

  16. Radionuclide concentrations in bed sediment and fish tissue within the Rio Grande drainage basin

    SciTech Connect

    Booher, J.L.; Fresquez, P.R.; Carter, L.F.; Gallaher, B.M.; Mullen, M.A.

    1998-02-01

    In 1992-93, Los Alamos National Laboratory collaborated with the U.S. Geological Survey in an effort to characterize radionuclide concentrations in bed sediment and fish tissue within the Rio Grande drainage basin from Colorado to Texas. Bed sediment was sampled from 18 locations for cesium ({sup 137}Cs), tritium ({sup 3}H), strontium ({sup 90}Sr), plutonium ({sup 238}Pu and {sup 239}Pu), americium ({sup 241}Am), total uranium ({sup tot}U) and alpha, beta, and gamma activity. Fish tissue was sampled from 12 locations for {sup 137}Cs, {sup 90}Sr, {sup 238}Pu, {sup 239}Pu and {sup tot}U.

  17. Delineating incised stream sediment sources within a San Francisco Bay tributary basin

    NASA Astrophysics Data System (ADS)

    Bigelow, Paul; Benda, Lee; Pearce, Sarah

    2016-07-01

    Erosion and sedimentation pose ubiquitous problems for land and watershed managers, requiring delineation of sediment sources and sinks across landscapes. However, the technical complexity of many spatially explicit erosion models precludes their use by practitioners. To address this critical gap, we demonstrate a contemporary use of applied geomorphometry through a straightforward GIS analysis of sediment sources in the San Francisco Bay Area in California, USA, designed to support erosion reduction strategies. Using 2 m lidar digital elevation models, we delineated the entire river network in the Arroyo Mocho watershed (573 km2) at the scale of ˜ 30 m segments and identified incised landforms using a combination of hillslope gradient and planform curvature. Chronic erosion to the channel network was estimated based on these topographic attributes and the size of vegetation, and calibrated to sediment gage data, providing a spatially explicit estimate of sediment yield from incised channels across the basin. Rates of erosion were summarized downstream through the channel network, revealing patterns of sediment supply at the reach scale. Erosion and sediment supply were also aggregated to subbasins, allowing comparative analyses at the scale of tributaries. The erosion patterns delineated using this approach provide land use planners with a robust framework to design erosion reduction strategies. More broadly, the study demonstrates a modern analysis of important geomorphic processes affected by land use that is easily applied by agencies to solve common problems in watersheds, improving the integration between science and environmental management.

  18. Abundant Atribacteria in deep marine sediment from the Adélie Basin, Antarctica

    PubMed Central

    Carr, Stephanie A.; Orcutt, Beth N.; Mandernack, Kevin W.; Spear, John R.

    2015-01-01

    Bacteria belonging to the newly classified candidate phylum “Atribacteria” (formerly referred to as “OP9” and “JS1”) are common in anoxic methane-rich sediments. However, the metabolic functions and biogeochemical role of these microorganisms in the subsurface remains unrealized due to the lack of pure culture representatives. In this study of deep sediment from Antarctica’s Adélie Basin, collected during Expedition 318 of the Integrated Ocean Drilling Program (IODP), Atribacteria-related sequences of the 16S rRNA gene were abundant (up to 51% of the sequences) and steadily increased in relative abundance with depth throughout the methane-rich zones. To better understand the metabolic potential of Atribacteria within this environment, and to compare with phylogenetically distinct Atribacteria from non-deep-sea environments, individual cells were sorted for single cell genomics from sediment collected from 97.41 m below the seafloor from IODP Hole U1357C. As observed for non-marine Atribacteria, a partial single cell genome suggests a heterotrophic metabolism, with Atribacteria potentially producing fermentation products such as acetate, ethanol, and CO2. These products may in turn support methanogens within the sediment microbial community and explain the frequent occurrence of Atribacteria in anoxic methane-rich sediments. This first report of a single cell genome from deep sediment broadens the known diversity within the Atribacteria phylum and highlights the potential role of Atribacteria in carbon cycling in deep sediment. PMID:26379647

  19. Evaluation of the effects of agricultural conservation practices on sediment yield in the Colusa Basin, California

    NASA Astrophysics Data System (ADS)

    Gatzke, S. E.; Zhang, M.

    2009-12-01

    The Soil and Water Assessment Tool (SWAT) was used to assess the impact of agricultural best management practices (BMPs) on sediment runoff from almond orchards in the lower Colusa Basin Drain watershed in the Sacramento Valley, California. This study used modeling techniques that include varying hydrologic parameters for both upland areas and small channels to quantify the effects of BMPs water quality. The BMPs simulated in this study are commonly used in almond orchards and include strip cropping, cover cropping, vegetative filter strips, grassed waterways and channel stabilization. The effectiveness of each BMP was simulated for an above average, below average and average rainfall year. Comparison of annual total watershed sediment loads for each BMP simulation showed that overall, channel stabilization and grassed waterways, which target in stream sediment erosion and transport, are the most effective BMPs with an estimated respective reduction in sediment load of 18% and 35% for a below average precipitation year, 13% and 26% for an above average precipitation year, and 17% and 30% for an average precipitation year. Simulations of BMPs designed to reduce sediment transport in upland areas, which include strip cropping and vegetative filter strips, estimated a reduction in total annual sediment load of less than 1% at the watershed outlet. These results indicated that in-stream sediment transport is the dominant sediment transport process in this watershed. Implementation of channel stabilization measures or grassed waterways on almond orchards is estimated to result in an annual reduction of total sediment load of 41,874 kg or 72,753 kg of sediment per square kilometer of almond orchard for an above average precipitation year.

  20. Water and Sediment Quality in the Yukon River Basin, Alaska, During Water Year 2005

    USGS Publications Warehouse

    Schuster, Paul F.

    2007-01-01

    OVERVIEW: This report contains water-quality and sediment-quality data from samples collected in the Yukon River Basin from March through September during the 2005 water year (WY). Samples were collected throughout the year at five stations in the basin (three on the main stem Yukon River, one each on the Tanana and Porcupine Rivers). A broad range of physical, chemical, and biological analyses are presented. This is the final report in a series of five USGS Open-File Reports spanning five WYs, from October 2000 through September 2005. The previous four reports are listed in the references (Schuster, 2003, 2005a, 2005b, 2006). Water-quality and sediment-quality data from samples collected on the Yukon River and selected major tributaries in Alaska for synoptic studies during WYs 2002-03 are published in Dornblaser and Halm (2006).

  1. Near-Infrared Spectroscopy of Lacustrine Sediments in the Great Salt Lake Desert: An Analog Study for Martian Paleolake Basins

    NASA Astrophysics Data System (ADS)

    Lynch, K. L.; Munkata Marr, J.; Horgan, B. H.; Hanley, J.; Rey, K. A.; Schneider, R. J.; Jackson, W. A.; Ritter, S. M.; Spear, J. R.

    2014-07-01

    Spectroscopic mineral identification of lacustrine sediments from Pilot Valley, Utah are compared to ground truth methods to evaluate VNIR spectroscopy as a characterization tool, and gain contextual insight into terrestrial paleolake basins.

  2. Fine-grained suspended sediment source identification for the Kharaa River basin, northern Mongolia

    NASA Astrophysics Data System (ADS)

    Rode, Michael; Theuring, Philipp; Collins, Adrian L.

    2015-04-01

    Fine sediment inputs into river systems can be a major source of nutrients and heavy metals and have a strong impact on the water quality and ecosystem functions of rivers and lakes, including those in semiarid regions. However, little is known to date about the spatial distribution of sediment sources in most large scale river basins in Central Asia. Accordingly, a sediment source fingerprinting technique was used to assess the spatial sources of fine-grained (<10 microns) sediment in the 15 000 km2 Kharaa River basin in northern Mongolia. Five field sampling campaigns in late summer 2009, and spring and late summer in both 2010 and 2011, were conducted directly after high water flows, to collect an overall total of 900 sediment samples. The work used a statistical approach for sediment source discrimination with geochemical composite fingerprints based on a new Genetic Algorithm (GA)-driven Discriminant Function Analysis, the Kruskal-Wallis H-test and Principal Component Analysis. The composite fingerprints were subsequently used for numerical mass balance modelling with uncertainty analysis. The contributions of the individual sub-catchment spatial sediment sources varied from 6.4% (the headwater sub-catchment of Sugnugur Gol) to 36.2% (the Kharaa II sub-catchment in the middle reaches of the study basin) with the pattern generally showing higher contributions from the sub-catchments in the middle, rather than the upstream, portions of the study area. The importance of riverbank erosion was shown to increase from upstream to midstream tributaries. The source tracing procedure provides results in reasonable accordance with previous findings in the study region and demonstrates the general applicability and associated uncertainties of an approach for fine-grained sediment source investigation in large scale semi-arid catchments. The combined application of source fingerprinting and catchment modelling approaches can be used to assess whether tracing estimates are

  3. Sediment discharge in the Upper Arroyo Grande and Santa Rita Creek basins, San Luis Obispo County, California

    USGS Publications Warehouse

    Knott, J.M.

    1976-01-01

    Sediment data collected in the upper Arroyo Grande and Santa Rita Creek basins, San Luis Obispo County, California, during the 1968-73 water years were analyzed to determine total sediment discharge at four stations in the basins. Water discharge and total sediment discharge at these stations, representative of the 1943-72 period, were estimated from long-term flow data for nearby gaging stations and water-sediment discharge relations determined for the 1968-73 water years. Most of the total annual sediment discharge at each station occurs during a few days each year. The quantity of sediment transported in a single day often accounts for more than 40 percent of the total annual sediment discharge. Estimated sediment discharge for the upper Arroyo Grande and Santa Rita Creek basins during the 1943-72 water years averaged 53,000 tons and 23,000 tons per year. Long-term sediment deposition in Lopez Reservoir, which is in the southern part of the upper Arroyo Grande basin, was estimated to be 35 acre-feet per year. (Woodard-USGS)

  4. Feedbacks of sedimentation on crustal heat flow - New insights from the Vøring Basin, Norwegian Sea

    NASA Astrophysics Data System (ADS)

    Theissen, S.; Ruepke, L. H.

    2009-04-01

    Information on the nature and origin of rift basins is preserved in the presently observed stratigraphy. Basin modeling aims at recovering this information with the goal of quantifying a basin's structural and thermal evolution. Decompaction and backstripping analysis is a classic and still popular approach to basin reconstruction [Steckler and Watts, 1978]. The total and tectonic subsidences, as well as sedimentation rates are calculated by the consecutive decompaction and removal of individual layers. The thermal history has to be computed separately using forward thermal models. An alternative is coupled forward modeling, where the structural and thermal history is computed simultaneously. A key difference between these reconstruction methods is that feedbacks of sedimentation on crustal heat flow are often neglected in backstripping methods. In this work we use the coupled basin modeling approach presented by Rüpke et al. [2008] to quantify some of the feedbacks between sedimentation and heat flow and to explore the differences between both reconstruction approaches in a case study from the Vøring Basin, Norwegian Sea. In a series of synthetic model runs we have reviewed the effects of sedimentation on basement heat flow. These example calculations clearly confirm the well-known blanketing effect of sedimentation and show that it is largest for high sedimentation rates. Recovery of sedimentation rates from the stratigraphy is, however, not straightforward. Decompaction-based methods may systematically underestimate sedimentation rates as sediment thickness is assumed to not change/thin during stretching. We present a new method for computing sedimentation rates based on forward modeling and demonstrate the differences between both methods in terms of rates and thermal feedbacks in a reconstruction of the Vøring basin (Euromargin transect 2). We find that sedimentation rates are systematically higher in forward models and heat flow is clearly depressed during

  5. Paleoproterozoic basin development and sedimentation in the Lake Superior region, North America

    USGS Publications Warehouse

    Ojakangas, R.W.; Morey, G.B.; Southwick, D.L.

    2001-01-01

    The peneplaned Archean craton in the Lake Superior region was the platform upon which a continental margin assemblage was deposited. Extension resulted in localized rifts that received thicker accumulations of sediments and volcanic rocks than did adjacent parts of the platform. Seas transgressed onto the continent several times and an ocean basin opened south of the present-day Lake Superior. Island arcs that formed during subduction collided with the craton margin as the ocean basin closed; oceanic crust is poorly preserved as a dismembered ophiolite sequence. The arc volcanics are preserved as the Wisconsin magmatic terranes. The collision resulted in a fold-and-thrust belt known as the Penokean orogen. To the north of the fold-and-thrust belt, a northward-migrating foreland basin - the Animikie basin - developed. Thick turbidite successions were deposited along the basin axis, and terrigenous clastics and Lake Superior-type iron-formation were deposited on the shelf along the northern margin of the basin. The primary paleoclimatic indicators are: (1) glaciogenic rocks at the base of the Paleoproterozoic succession in Michigan indicating ice-house conditions; 2) remnants of a paleosol on the glaciogenic rocks indicative of deep weathering, probably under subtropical conditions and therefore of greenhouse conditions; and (3) carbonate minerals after gypsum, halite, and anhydrite in stromatolitic dolomite, indicative of aridity. Three second-order depositional sequences are bounded by major unconformities, and can be correlated throughout the Lake Superior region. ?? 2001 Elsevier Science B.V. All rights reserved.

  6. Sediment from hydraulic mining detained by Englebright and small dams in the Yuba basin

    NASA Astrophysics Data System (ADS)

    James, L. Allan

    2005-10-01

    Recent initiatives to find ways to reintroduce anadromous fish to the Central Valley of California have identified the Yuba River as one of the best potential watersheds for expanding spawning habitat of spring-run chinook salmon and steelhead trout. Salmon spawning in the Yuba River would require substantial modifications or removal of Englebright Dam, a large dam (86 million m3 capacity) built by the U.S. Army Corps of Engineers in 1941. An extensive on-going feasibility study by local, state, and federal organizations, therefore, is examining aspects of various dam-treatment scenarios that range from no action to complete dam removal. This paper examines the extraordinary history of the watershed and resulting conditions pertinent to the feasibility of altering Englebright Dam. It seeks to accomplish four goals. First, historical geomorphic changes in the watershed are outlined that influence the physical context of the feasibility study. The Yuba watershed is centered in the hydraulic gold-mining region made famous by G.K. Gilbert (Gilbert, G.K., 1917. Hydraulic-mining débris in the Sierra Nevada. U.S. Geol. Survey Prof. Paper 105 154 pp.), and Englebright Dam was built as a débris dam to control the sediment from hydraulic mining. Second, recent findings of high concentrations of mercury in sediment and fish tissues in the watershed are briefly reviewed. Much mercury was applied during the 20th century. Third, historic data on 20th century hydraulic mining are presented that document numerous small dams built in the Yuba basin to detain mining sediment. Finally, field measurements of the texture and lithology of modern bed materials in the Yuba River basin are presented that demonstrate reworked sediment from mining is an important component of the modern sediment load and fine spawning gravels. The complex anthropogenic geomorphic changes in the Yuba basin present a challenge with regards to responsible treatment of Englebright Dam. If toxic sediment is

  7. Walker Lake, Nevada: sedimentation in an active, strike-slip related basin

    SciTech Connect

    Link, M.H.; Roberts, M.T.

    1984-04-01

    Walker Lake, Nevada, is in an active fault-controlled basin related to the right-lateral, northwest-trending Walker Lane Shear Zone on the western side of the Basin and Range province. The lake occurs in a half graben bounded on its west side by a high-angle normal fault zone along the Wassuk Range front. This fault zone may merge to the north into the Walker Lane fault system, which forms the northeast boundary of the basin. To the south of Walker Lake, the Wassuk front fault merges with an east-northeast trending left-lateral fault. The Walker Lake basin is interpreted to be a pull-apart basin formed within the triangular zone bounded by the Wassuk front, the Walker Lane, and left-lateral faults. The Walker River drainage basin occupies about 10,000 km/sup 2/ (3800 mi/sup 2/) in western Nevada and parts of California and is essentially a closed hydrologic system that drains from the crest of the Sierra Nevada in California and terminates in Walker Lake. Walker Lake trends north-northwest and is 27.4 km (17 mi) long and 8 km (5 mi) wide with water depths exceeding 30 m (100 ft). Lake Lahontan (Wisconsinian) shorelines ring Walker Lake and suggest water depths of 150 m (500 ft) above the present lake level. The lake is situated in an asymmetric basin with steep alluvial fans flanking the western shoreline (Wassuk Range) and gentle, areally more extensive fans flanking the eastern shoreline (Gillis Range). The Walker River delta enters the lake from the north and is a major sediment point source for the basin. Older dissected shoreline, alluvial fan, Gilbert delta, and beach ridge deposits were built largely of coarse-grained, locally derived materials. Stromatolites, oncolites, and tufas formed along the shorelines, whereas mud and organic sediments accumulated in the lake on the west side of the basin. Extensive submerged sand flats and local sand dunes occur on the east side of the basin.

  8. Gravel sediment routing from widespread, low-intensity landscape disturbance, Current River basin, Missouri

    USGS Publications Warehouse

    Jacobson, R.B.; Gran, K.B.

    1999-01-01

    During the last 160 years, land-use changes in the Ozarks have had the potential to cause widespread, low-intensity delivery of excess amounts of gravel-sized sediment to stream channels. Previous studies have indicated that this excess gravel bedload is moving in wave-like forms through Ozarks drainage basins. The longitudinal, areal distribution of gravel bars along 160 km of the Current River, Missouri, was evaluated to determine the relative effects of valley-scale controls, tributary basin characteristics, and lagged sediment transport in creating areas of gravel accumulations. The longitudinal distribution of gravel-bar area shows a broad scale wave-like form with increases in gravel-bar area weakly associated with tributary junctions. Secondary peaks of gravel area with 1.8-4.1 km spacing (disturbance reaches) are superimposed on the broad form. Variations in valley width explain some, but not all, of the short-spacing variation in gravel-bar area. Among variables describing tributary drainage basin morphometry, present-day land use and geologic characteristics, only drainage area and road density relate even weakly to gravel-bar areal inventories. A simple, channel network-based sediment routing model shows that many of the features of the observed longitudinal gravel distribution can be replicated by uniform transport of sediment from widespread disturbances through a channel network. These results indicate that lagged sediment transport may have a dominant effect on the synoptic spatial distribution of gravel in Ozarks streams; present-day land uses are only weakly associated with present-day gravel inventories; and valley-scale characteristics have secondary controls on gravel accumulations in disturbance reaches.

  9. Dam sediment tracking using spectrometry and Landsat 8 satellite image, Taleghan Basin, Iran.

    PubMed

    Afshar, Sirous; Shamsai, Abolfazl; Saghafian, Bahram

    2016-02-01

    Sedimentation in reservoirs, in addition to reducing water storage capacity, causes serious environmental impacts including intensification of river erosion. Detection of sediment origins plays a determining role in control and prevention of sedimentation. Nowadays, with the help of studies on sedimentation and erosion, sediment origins can be detected with high accuracy. This research integrated geographic information system (GIS) and remote sensing (RS) techniques to detect the primary source of sediment to Taleghan Dam in northern Iran. After collecting samples of sediment from the basin outlet, they were divided into two parts. One part was sent to the Mineralogy Laboratory in order to determine the percentage of each mineral in the samples using X-ray. A few were sent to the Spectroscopy Laboratory to determine their spectral signature using the spectrometer. The laboratory test results determined the wavelength of the minerals. In the next step, those spots on the satellite image whose spectral reflectance fell within the spectral signature of the minerals were detected and enhanced by mixture-tuned matched filtering (MTMF) method. These spots were overlapped with the map of geological formations. Accordingly, the origin of the minerals was detected. The greatest proportion of trace minerals was found in sample 4 including 6% of Illite trace mineral, while sample 2 contains only 2% of trace minerals. Accordingly, the origin of the minerals was detected. The obtained results revealed that mudstone, red siltstone, and conglomerate formations, Karaj formation in section Poldokhtar, acidic tuffs, alcanic lavas of Karaj Formation, mudstone and gypsum of upper red formation, and Cambrian dolomites were recognized as the most possible origins of the dam sediments. These formations are vulnerable to erosion and should be conserved so as to substantially prevent the volume of sedimentation in the reservoir.

  10. Riparian Vegetation, Sediment Dynamics and Hydrologic Change in the Minnesota River Basin

    NASA Astrophysics Data System (ADS)

    Batts, V. A.; Triplett, L.; Gran, K. B.; Lenhart, C. F.

    2014-12-01

    In the last three decades the Minnesota River Basin (MRB) has experienced increased precipitation and anthropogenic alteration to the drainage network, which contributes to higher flows and increased sediment loading. From field and laboratory approaches, this study investigates the implications of hydrologic change on the colonization of riparian vegetation on pointbars, and of vegetation loss on near-channel sediment storage within the lower Minnesota River. Field surveys consisted of vegetation surveys along pointbars, which were then related to flow records. Surveys revealed a dominance of woody seedlings over older established saplings, and high frequencies of species with alternative forms of propagation that tolerate high flows such as sandbar willow (Salix interior), and beggarticks (Bidens sp.). Surveys also showed in increase in elevation of plant establishment from measurements taken in 1979, resulting in higher area of exposed pointbar and easier mobilization of sediment. Geospatial analysis completed at each sampling location found decreased area of exposed pointbar in association with increases in pointbar vegetation between lower flow years and increased area of exposed pointbar in association with decreased pointbar vegetation between higher flow years. An experimental approach addresses implications of vegetation loss on pointbar sediment storage. In a 1.5m x 6m flume, we are conducting experiments to measure the efficiency of bar vegetation in trapping fine sediment as a function of stem density. Self-formed pointbars are vegetated at varying densities with Medicago sativa (alfalfa) sprouts to represent riparian woody saplings, then flooded with fine sediment-rich water to simulate summer flooding. Sediment deposited at each stem density is then measured to estimate efficiency. While results of these experiments are currently ongoing, we hypothesize that a threshold density exists at which trapping efficiency declines substantially. Preliminary

  11. Dam sediment tracking using spectrometry and Landsat 8 satellite image, Taleghan Basin, Iran.

    PubMed

    Afshar, Sirous; Shamsai, Abolfazl; Saghafian, Bahram

    2016-02-01

    Sedimentation in reservoirs, in addition to reducing water storage capacity, causes serious environmental impacts including intensification of river erosion. Detection of sediment origins plays a determining role in control and prevention of sedimentation. Nowadays, with the help of studies on sedimentation and erosion, sediment origins can be detected with high accuracy. This research integrated geographic information system (GIS) and remote sensing (RS) techniques to detect the primary source of sediment to Taleghan Dam in northern Iran. After collecting samples of sediment from the basin outlet, they were divided into two parts. One part was sent to the Mineralogy Laboratory in order to determine the percentage of each mineral in the samples using X-ray. A few were sent to the Spectroscopy Laboratory to determine their spectral signature using the spectrometer. The laboratory test results determined the wavelength of the minerals. In the next step, those spots on the satellite image whose spectral reflectance fell within the spectral signature of the minerals were detected and enhanced by mixture-tuned matched filtering (MTMF) method. These spots were overlapped with the map of geological formations. Accordingly, the origin of the minerals was detected. The greatest proportion of trace minerals was found in sample 4 including 6% of Illite trace mineral, while sample 2 contains only 2% of trace minerals. Accordingly, the origin of the minerals was detected. The obtained results revealed that mudstone, red siltstone, and conglomerate formations, Karaj formation in section Poldokhtar, acidic tuffs, alcanic lavas of Karaj Formation, mudstone and gypsum of upper red formation, and Cambrian dolomites were recognized as the most possible origins of the dam sediments. These formations are vulnerable to erosion and should be conserved so as to substantially prevent the volume of sedimentation in the reservoir. PMID:26790431

  12. Phosphorus burial in Cariaco Basin sediments through the last glacial - interglacial transition

    NASA Astrophysics Data System (ADS)

    Whitehill, A. R.; Ruttenberg, K. C.; Briggs, R.; Lyons, T. W.; Colman, A. S.

    2008-12-01

    On geologic timescales, phosphate availability in the oceans limits global organic carbon burial rates in marine sediments. The phosphate inventory of the oceans is strongly influenced by early diagenetic regeneration of phosphate in marine sediments. Oxic conditions are generally thought to favor phosphate retention in marine sediments, whereas anoxic conditions permit a greater fraction of reactive particulate phosphate to be released to pore waters and return to the overlying water column. Feedbacks with the marine phosphorus cycle can act to stabilize ocean anoxic events and control atmospheric oxygen concentrations. We analyzed phosphorus phase associations in Cariaco Basin sediments through the transition from oxidized sediments that characterized deposition during the last glacial period through laminated anoxic sediments that characterize Holocene deposition. We have used a sequential extraction technique (SEDEX) on samples from ODP core 1002 in order to target adsorbed phosphate, ferric iron associated P, authigenic and biogenic P phases, detrital apatite, and organic P. Preliminary results show a correlation between total organic carbon and reactive phosphate in the sediments. The anoxic sediments are dominated by the authigenic and biogenic P pool, which typically represents 60-80% of the total P. These values, coupled with high C-org/P-org (> 600) and C-org/P- reactive (> 300) ratios, suggest post-depositional redistribution of P from organic matter to authigenic carbonate fluorapatite and substantial regeneration of phosphate to the overlying water column. C/P ratios are much lower in the oxic sediments, though the authigenic and biogenic P pool remains quantitatively most significant. Throughout the core, changes in C:P ratios and the concentration of authigenic P appear to correlate with changes in the Mo/Al ratio, further linking P burial and diagenesis to water column anoxia.

  13. Constraining the Equatorial Basins Sedimentation Chronology from MARSIS Tomographic Data Analysis

    NASA Astrophysics Data System (ADS)

    Heggy, E.; Boisson, J.; Clifford, S. M.; Plaut, J. J.; Ferro, A.; Gim, Y.

    2010-12-01

    Martian hydrogeologic surface chronology strongly depends on our understanding of the cratering process and our ability to perform surface crater count to assess rough formation ages. Of particular interest are Isidis and Amazonis Planitia as both basins are among the smoothest surface areas on Mars with very few observable large craters. Such surface conditions give a unique potential to the current sounding radars to overcome clutter arising from surface textural and topographic complexity to assess the dielectric properties of the shallow subsurface and also to attempt to explore potential buried large craters that could constrain the ambiguities on the chronology and type of sedimentation that filled these two basins. Isidis has been hypothesized to be filled by either sediments derived from drainage leading into those lower topographic zones or by an older paleo-ocean. It has been suggested that those large-scale sedimentary deposits may still be volatile-rich. The Gamma Ray Spectroscopy Observations onboard Mars Odyssey suggested a maximum inferred water abundance of 3wt% in the top few meters. For Amazonis Planitia, it has been hypothesized that Tharsis produced lava flows that formed a barrier across the plain, which in turn created a basin that collected lava flows and other sediments. It is assumed that this basin and the repeated flows of lava and sedimentary materials through it, causing the smoothness of the plain, especially in the southern part of the basin. In order to constrain the chronology, origin and type of each of these basin fills, we created three-dimensional regional-normalized attenuation maps of the surface and shallow subsurface using the signal-decay method to provide insights into the three-dimensional variations of dielectric properties within these terrains. MARSIS radar tomography on Isidis yielded a complex large-scale westward flow-like pattern and ponding that appears to be similar to many of earth dry lakes. The attenuation

  14. Transtensional arm of the early Mesozoic Fundy rift basin: Penecontemporaneous faulting and sedimentation

    SciTech Connect

    Olsen, P.E.; Schlische, R.W. )

    1990-08-01

    Formed as a major right-lateral fault zone during Paleozoic collisional orogenies and reactivated as a left-oblique system during the early Mesozoic, the east-striking Minas fault zone of Atlantic Canada controlled adjacent sedimentation in the Fundy rift basin, producing a series of synsedimentary microbasins. Northeast-striking boundary faults of the Fundy basin underwent mostly early Mesozoic normal slip and are reactivated Paleozoic thrusts. The adjacent basin has a much thicker section, transverse folds, and synthetic rider blocks. Contrasts in structural and stratigraphic styles are a response to local deformation controlled by reactivated fault zones of differing orientation under consistent northwest-southeast early Mesozoic extension rather than responses to a sequence of changing stress patterns.

  15. Biosphere frontiers of subsurface life in the sedimented hydrothermal system of Guaymas Basin.

    PubMed

    Teske, Andreas; Callaghan, Amy V; LaRowe, Douglas E

    2014-01-01

    Temperature is one of the key constraints on the spatial extent, physiological and phylogenetic diversity, and biogeochemical function of subsurface life. A model system to explore these interrelationships should offer a suitable range of geochemical regimes, carbon substrates and temperature gradients under which microbial life can generate energy and sustain itself. In this theory and hypothesis article, we make the case for the hydrothermally heated sediments of Guaymas Basin in the Gulf of California as a suitable model system where extensive temperature and geochemical gradients create distinct niches for active microbial populations in the hydrothermally influenced sedimentary subsurface that in turn intercept and process hydrothermally generated carbon sources. We synthesize the evidence for high-temperature microbial methane cycling and sulfate reduction at Guaymas Basin - with an eye on sulfate-dependent oxidation of abundant alkanes - and demonstrate the energetic feasibility of these latter types of deep subsurface life in previously drilled Guaymas Basin locations of Deep-Sea Drilling Project 64.

  16. Morrowan sedimentation in the Orogrande basin, west Texas and south-central New Mexico

    SciTech Connect

    Connolly, W.M.; Stanton, R.J. Jr.

    1986-03-01

    Morrowan strata in the Hueco and Franklin Mountains reflect deposition within a shallow, gradually subsiding, carbonate shelf lagoon. Postulated environments fluctuated between open shelf lagoon with localized shoaling, restricted inner shelf lagoon, and peritidal settings. Variations in depth were slight, probably not exceeding several tens of meters within the photic zone. The La Tuna Formation (Franklin Mountains) was deposited near the axis (center) of the Orogrande basin; the lower division of the Magdalena limestone (Hueco Mountains), 30 mi east, was deposited 20-30 mi west of the paleoshoreline. Physiographically, the Orogrande sea was a small gulf, offering a certain degree of protection from the Morrowan seaway to the south. Sedimentologically, it was a wide expanse of predominantly quiet-water carbonate sedimentation with subordinate argillaceous influex and coarser peripheral clastics. The Orogrande basin, a stratigraphic feature, corresponds to a blanket deposit of shallow epeiric carbonates. Climatic and orographic effects are invoked to explain the contrasting style of clastic sedimentation in the Delaware and orogrande basins, east and west of the Pedernal uplift. Analysis of Morrowan carbonates reveals no evidence of cyclicity, major transgressions or regressions, or local tectonic activity. Deposition was stable and in equilibrium with a gradually subsiding shallow basin. Based on lithologic, faunal, biostratigraphic, and paleogeographic criteria, the lower division is both laterally and temporally equivalent with the La Tuna Formation. Accordingly, the latter term is advocated in favor of the former, which lacks both priority and formal status.

  17. Tracing suspended sediment sources in the Upper Sangamon River Basin using conservative and non-conservative tracers

    NASA Astrophysics Data System (ADS)

    Yu, M.; Rhoads, B. L.; Stumpf, A.

    2015-12-01

    As the awareness of water pollution, eutrophication and other water related environmental concerns grows, the significance of sediment in the transport of nutrients and contaminants from agricultural areas to streams has received increasing attention. Both the physical and geochemical properties of suspended sediment are strongly controlled by sediment sources. Thus, tracing sources of suspended sediment in watersheds is important for the design of management practices to reduce sediment loads and contributions of sediment-adsorbed nutrients from agricultural areas to streams. However, the contributions of different sediment sources to suspended sediment loads within intensively managed watersheds in the Midwest still remain insufficiently explored. This study aims to assess the provenance of suspended sediment and the relation between channel morphology and production of suspended sediment in the Upper Sangamon River Basin, Illinois, USA. The 3,690-km2 Upper Sangamon River Basin is characterized by low-relief, agricultural lands dominated by row-crop agriculture. Sediment source samples were collected in the Saybrook from five potential sources: farmland, forests, floodplains, river banks, and grasslands. Event-based and accumulated suspended sediment samples were collected by ISCO automatic pump samplers and in situ suspended sediment samplers and from the stream at watershed outlet. A quantitative geochemical fingerprinting technique, combining statistically verified multicomponent signatures and an un-mixing model, was employed to estimate the relative contributions of sediment from five potential sources to the suspended sediment loads. Organic matter content, trace elements, and radionuclides from soil samples were used as potential tracers. Our preliminary results indicate that the majority of suspended sediment is derived from floodplains in the downstream portions of the watersheds, while only minor amounts of suspended sediment are derived from upland

  18. Archaeal communities associated with shallow to deep subseafloor sediments of the New Caledonia Basin.

    PubMed

    Roussel, Erwan G; Sauvadet, Anne-Laure; Chaduteau, Carine; Fouquet, Yves; Charlou, Jean-Luc; Prieur, Daniel; Cambon Bonavita, Marie-Anne

    2009-09-01

    The distribution of the archaeal communities in deep subseafloor sediments [0-36 m below the seafloor (mbsf)] from the New Caledonia and Fairway Basins was investigated using DNA- and RNA-derived 16S rRNA clone libraries, functional genes and denaturing gradient gel electrophoresis (DGGE). A new method, Co-Migration DGGE (CM-DGGE), was developed to access selectively the active archaeal diversity. Prokaryotic cell abundances at the open-ocean sites were on average approximately 3.5 times lower than at a site under terrestrial influence. The sediment surface archaeal community (0-1.5 mbsf) was characterized by active Marine Group 1 (MG-1) Archaea that co-occurred with ammonia monooxygenase gene (amoA) sequences affiliated to a group of uncultured sedimentary Crenarchaeota. However, the anoxic subsurface methane-poor sediments (below 1.5 mbsf) were dominated by less active archaeal communities, such as the Thermoplasmatales, Marine Benthic Group D and other lineages probably involved in the methane cycle (Methanosarcinales, ANME-2 and DSAG/MBG-B). Moreover, the archaeal diversity of some sediment layers was restricted to only one lineage (Uncultured Euryarchaeota, DHVE6, MBG-B, MG-1 and SAGMEG). Sequences forming two clusters within the Thermococcales order were also present in these cold subseafloor sediments, suggesting that these uncultured putative thermophilic archaeal communities might have originated from a different environment. This study shows a transition between surface and subsurface sediment archaeal communities.

  19. Benthic protists and fungi of Mediterranean deep hypsersaline anoxic basin redoxcline sediments

    PubMed Central

    Bernhard, Joan M.; Kormas, Konstantinos; Pachiadaki, Maria G.; Rocke, Emma; Beaudoin, David J.; Morrison, Colin; Visscher, Pieter T.; Cobban, Alec; Starczak, Victoria R.; Edgcomb, Virginia P.

    2014-01-01

    Some of the most extreme marine habitats known are the Mediterranean deep hypersaline anoxic basins (DHABs; water depth ∼3500 m). Brines of DHABs are nearly saturated with salt, leading many to suspect they are uninhabitable for eukaryotes. While diverse bacterial and protistan communities are reported from some DHAB water-column haloclines and brines, the existence and activity of benthic DHAB protists have rarely been explored. Here, we report findings regarding protists and fungi recovered from sediments of three DHAB (Discovery, Urania, L’ Atalante) haloclines, and compare these to communities from sediments underlying normoxic waters of typical Mediterranean salinity. Halocline sediments, where the redoxcline impinges the seafloor, were studied from all three DHABs. Microscopic cell counts suggested that halocline sediments supported denser protist populations than those in adjacent control sediments. Pyrosequencing analysis based on ribosomal RNA detected eukaryotic ribotypes in the halocline sediments from each of the three DHABs, most of which were fungi. Sequences affiliated with Ustilaginomycotina Basidiomycota were the most abundant eukaryotic signatures detected. Benthic communities in these DHABs appeared to differ, as expected, due to differing brine chemistries. Microscopy indicated that only a low proportion of protists appeared to bear associated putative symbionts. In a considerable number of cases, when prokaryotes were associated with a protist, DAPI staining did not reveal presence of any nuclei, suggesting that at least some protists were carcasses inhabited by prokaryotic scavengers. PMID:25452749

  20. Benthic protists and fungi of Mediterranean deep hypsersaline anoxic basin redoxcline sediments.

    PubMed

    Bernhard, Joan M; Kormas, Konstantinos; Pachiadaki, Maria G; Rocke, Emma; Beaudoin, David J; Morrison, Colin; Visscher, Pieter T; Cobban, Alec; Starczak, Victoria R; Edgcomb, Virginia P

    2014-01-01

    Some of the most extreme marine habitats known are the Mediterranean deep hypersaline anoxic basins (DHABs; water depth ∼3500 m). Brines of DHABs are nearly saturated with salt, leading many to suspect they are uninhabitable for eukaryotes. While diverse bacterial and protistan communities are reported from some DHAB water-column haloclines and brines, the existence and activity of benthic DHAB protists have rarely been explored. Here, we report findings regarding protists and fungi recovered from sediments of three DHAB (Discovery, Urania, L' Atalante) haloclines, and compare these to communities from sediments underlying normoxic waters of typical Mediterranean salinity. Halocline sediments, where the redoxcline impinges the seafloor, were studied from all three DHABs. Microscopic cell counts suggested that halocline sediments supported denser protist populations than those in adjacent control sediments. Pyrosequencing analysis based on ribosomal RNA detected eukaryotic ribotypes in the halocline sediments from each of the three DHABs, most of which were fungi. Sequences affiliated with Ustilaginomycotina Basidiomycota were the most abundant eukaryotic signatures detected. Benthic communities in these DHABs appeared to differ, as expected, due to differing brine chemistries. Microscopy indicated that only a low proportion of protists appeared to bear associated putative symbionts. In a considerable number of cases, when prokaryotes were associated with a protist, DAPI staining did not reveal presence of any nuclei, suggesting that at least some protists were carcasses inhabited by prokaryotic scavengers.

  1. Benthic protists and fungi of Mediterranean deep hypsersaline anoxic basin redoxcline sediments.

    PubMed

    Bernhard, Joan M; Kormas, Konstantinos; Pachiadaki, Maria G; Rocke, Emma; Beaudoin, David J; Morrison, Colin; Visscher, Pieter T; Cobban, Alec; Starczak, Victoria R; Edgcomb, Virginia P

    2014-01-01

    Some of the most extreme marine habitats known are the Mediterranean deep hypersaline anoxic basins (DHABs; water depth ∼3500 m). Brines of DHABs are nearly saturated with salt, leading many to suspect they are uninhabitable for eukaryotes. While diverse bacterial and protistan communities are reported from some DHAB water-column haloclines and brines, the existence and activity of benthic DHAB protists have rarely been explored. Here, we report findings regarding protists and fungi recovered from sediments of three DHAB (Discovery, Urania, L' Atalante) haloclines, and compare these to communities from sediments underlying normoxic waters of typical Mediterranean salinity. Halocline sediments, where the redoxcline impinges the seafloor, were studied from all three DHABs. Microscopic cell counts suggested that halocline sediments supported denser protist populations than those in adjacent control sediments. Pyrosequencing analysis based on ribosomal RNA detected eukaryotic ribotypes in the halocline sediments from each of the three DHABs, most of which were fungi. Sequences affiliated with Ustilaginomycotina Basidiomycota were the most abundant eukaryotic signatures detected. Benthic communities in these DHABs appeared to differ, as expected, due to differing brine chemistries. Microscopy indicated that only a low proportion of protists appeared to bear associated putative symbionts. In a considerable number of cases, when prokaryotes were associated with a protist, DAPI staining did not reveal presence of any nuclei, suggesting that at least some protists were carcasses inhabited by prokaryotic scavengers. PMID:25452749

  2. Floodplains and Sedimentation Processes in a Changing Basin: Case Study Sacramento Valley

    NASA Astrophysics Data System (ADS)

    Singer, M. B.; Aalto, R.

    2006-12-01

    The diverse floodplains of the Sacramento Valley in California have undergone dramatic post-glaciation changes. The natural reduction in sediment supply following glacial melting appears to have altered channel pattern of the in the Middle Sacramento River from braided to meandering. This trend has been exacerbated by recent dam construction, gravel and sand mining, and bank protection, which have apparently increased the frequency of chute cutoff and decreased channel sinuosity. The sum of factors controlling sediment supply and channel pattern are evidently converting the Sacramento from an aggraded river with frequent access to its natural floodplain to a degrading river with limited connectivity. We have documented via 210Pb dating low volumes of recent sediment transfer to: inset floodplains in Upper Sacramento River canyons; meander belt deposits, low-lying sinks bounding natural levees, and oxbow lakes along the Middle Sacramento River; and crevasses splay deposits and lowland floodways in the Lower Sacramento Valley. These observations are contrasted with historical maps and preserved deposits from the previous era of floodplain creation, which suggest higher rates of sediment accumulation. The presence of high sand content in recent deposits along channel margins determined via granulometry and its rapid decline with depth and distance from the channel attests to recent erosion of channel sediments throughout the Sacramento River. Most of the natural crevasses splays that once dominated sediment transfer into floodplains along the Sacramento's lower course have been cut off from the channel by flood control levees built upon channel banks. However, several splay fans were retrofitted for use in the valley's flood control system (c. 1920's) as lateral spill weirs that shunt flood flow out of the mainstem Sacramento River. These weirs focus flow and sediment transport into engineered floodways (i.e., leveed portions of natural low gradient flood basins

  3. Sr and Nd isotopes of suspended sediments from rivers of the Amazon basin

    NASA Astrophysics Data System (ADS)

    Hatting, Karina; Santos, Roberto V.; Sondag, Francis

    2014-05-01

    The Rb-Sr and Sm-Nd isotopic systems are important tools to constrain the provenance of sediment load in river systems. This study presents the isotopic composition of Sr and Nd isotopes and major and minor elements in suspended sediments from the Marañón-Solimões, Amazonas and Beni-Madeira rivers. The data were used to constrain the source region of the sediments and to better understand the main seasonal and spatial transport processes within the basin based on the variations of the chemical and isotopic signals. They also allow establishing a relationship between sediment concentrations and flow rate values. The study presents data collected during a hydrological year between 2009 and 2010. The Marañón-Solimões River presents low Sr isotopic values (0.7090-0.7186), broad EpslonNd(0) range (-15.17 to -8.09) and Nd model (TDM) ages varying from 0.99 to 1.81 Ga. Sources of sediments to the Marañón-Solimões River include recent volcanic rocks in northern Peru and Ecuador, as well as rocks with long crustal residence time and carbonates from the Marañón Basin, Peru. The Beni-Madeira River has more radiogenic Sr isotope values (0.7255-0.7403), more negative EpslonNd(0) values (-20.46 to -10.47), and older Nd isotope model ages (from 1.40 to 2.35 Ga) when compared to the Marañón-Solimões River. These isotope data were related to the erosion of Paleozoic and Cenozoic foreland basins that are filled with Precambrian sediments derived from the Amazonian Craton. These basins are located in Bolivian Subandina Zone. The Amazon River presents intermediate isotopic values when compared to those found in the Marañón-Solimões and Beni-Madeira rivers. Its Sr isotope ratios range between 0.7193 and 0.7290, and its EpslonNd(0) values varies between -11.09 and -9.51. The Nd isotope model ages of the suspended sediments vary between 1.28 and 1.77 Ga. Concentrations of soluble and insoluble elements indicate a more intense weathering activity in sediments of the Beni

  4. Distribution of maximum burial temperatures across northern Appalachian Basin and implications for Carboniferous sedimentation patterns

    SciTech Connect

    Johnsson, M.J.

    1986-05-01

    Clay-mineral diagenesis and apatite fission-track age data indicate that the maximum burial temperatures to which the Middle Devonian Tioga metabentonite was exposed rise abruptly from low values in western New York State to higher values in the east. The highest temperatures, which approach 175/sup 0/C, were reached just west of Syracuse. Neither the pattern nor the magnitude of burial temperatures can be explained solely by burial of the metabentonite beneath Upper Devonian sediments. Although spatial variations in the geothermal gradient could have produced the observed pattern of burial temperatures, it is more likely that Carboniferous sediments, no longer preserved in the area, were responsible for the indicated burial. The inferred presence of thick Carboniferous sequences in western New York State suggests that the Allegheny orogeny had a stronger influence on sedimentation in the northern Appalachian Basin than has been previously recognized. 25 references, 2 figures, 2 tables.

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

    USGS Publications Warehouse

    Cooley, Maurice E.

    1979-01-01

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

  6. History of suspended-sediment data collection and inventory of available data for the Tennessee and Cumberland River basins

    USGS Publications Warehouse

    Carey, William P.; Brown, Russell T.; Chatham, Carrie G.

    1988-01-01

    In 1934 and 1935, the Tennessee Valley Authority established 51 daily record suspended-sediment stations on the Tennessee River and its major tributaries. Most of these stations were operated for 8 years. From 1962 to 1965, the Tennessee Valley Authority again collected daily sediment record at 10 of the original 49 stations. In addition to the data sets collected on the major rivers, the Tennessee Valley Authority has conducted several intensive studies of small watersheds throughout the Tennessee River basin. In the Cumberland River basin, daily sediment records have been collected primarily by the Survey. Daily stations have been operated for various periods on 17 basins ranging in size from 0.67 to 1,977 sq mi, with the earliest data of daily record being October 1953. All of these daily stations are located in the upper Cumberland River basin upstream of any major impoundments. Periodic sediment data have been collected by the Survey at 194 stations in the Tennessee River basin and at 106 stations in the Cumberland River basin, however; the number of samples/station is quite low. 86% of the periodic stations in the Tennessee River basin and 91% of the periodic stations in the Cumberland River basin have 30 samples or less. (USGS)

  7. Heavy-metal pollution of sediments from Szczecin Lagoon and the Gdansk Basin, Poland.

    PubMed

    Glasby, G P; Szefer, P; Geldon, J; Warzocha, J

    2004-09-01

    Concentrations of Al, V, Mn, Fe, Co, Cu, Ni, Zn, Sr, Mo, Cd, Sb, Pb, Th, U, REE, Na, K, Mg, Ca, Si, P, S, Ti, Cr and Ba were determined in the <63 microm fraction of bottom sediments of the Szczecin Lagoon and the Gdansk Basin, Baltic Sea, by ICP-MS, ICP-AES and XRF methods. Sediment samples from the Szczecin Lagoon displayed somewhat higher concentrations of P, Mn, Cr, Cu and possibly Cd, Pb and Zn in those collected in October 1997 after the exceptional flooding of the Oder River than in those collected in December 2000. The data suggest that the flood resulted in the enhanced transport of redox-sensitive and anthropogenic elements in the Oder River and their subsequent redeposition mainly in the western part of Szczecin Lagoon. The sediments of the Szczecin Lagoon also appear to be the most polluted with heavy metals within the Polish Exclusive Economic Zone (EEZ) of the Baltic Sea. Cd, Pb, Zn and Cu are anthropogenically enriched in top layers of sediment cores from the Gdansk Basin, but the decrease of these elements with depth in the core is not systematic. The rare earth element (REE) patterns in sediments from both these areas do not appear to have been greatly modified during transport from their source into the southern Baltic. Factor analysis (FA) of the compositional data shows that sediments from Szczecin Lagoon can be divided into three main groups depending on their composition. It is concluded that clay minerals and organic matter build aggregates and flocs, which effectively concentrate trace metals and sink down to form a 'fluffy layer'. PMID:15325172

  8. Managing flow, sediment, and hydropower regimes in the Sre Pok, Se San, and Se Kong Rivers of the Mekong basin

    NASA Astrophysics Data System (ADS)

    Wild, Thomas B.; Loucks, Daniel P.

    2014-06-01

    The Lancang/Mekong River Basin is presently undergoing a period of rapid hydropower development. In its natural undeveloped state, the river transports about 160 million metric tons of sediment per year, maintaining the geomorphologic features of the basin, sustaining habitats, and transporting the nutrients that support ecosystem productivity. Despite the importance of sediment in the river, currently little attention is being paid to reservoir sediment trapping. This study is devoted to assessing the potential for managing sediment and its impact on energy production in the Se San, Sre Pok, and Se Kong tributaries of the Mekong River. These tributaries drain a set of adjacent watersheds that are important with respect to biodiversity and ecological productivity, and serve as a significant source of flow and sediment to the mainstream Mekong River. A daily sediment transport model is used to assess tradeoffs among energy production and sediment and flow regime alteration in multiple reservoir systems. This study finds that eventually about 40%-80% of the annual suspended sediment load may be trapped in reservoirs. Clearly, these reservoirs will affect the rivers' sediment regimes. However, even after 100 years of simulated sedimentation, reservoir storage capacities and hydropower production at most reservoir sites are not significantly reduced. This suggests that the strongest motivation for implementing measures to reduce trapped sediment is their impact not on hydropower production but on fish migration and survival and on sediment-dependent ecosystems such as the Vietnam Delta and Cambodia's Tonle Sap Lake.

  9. Changes in sediment volume in Alder Lake, Nisqually River Basin, Washington, 1945-2011

    USGS Publications Warehouse

    Czuba, Jonathan A.; Olsen, Theresa D.; Czuba, Christiana R.; Magirl, Christopher S.; Gish, Casey C.

    2012-01-01

    The Nisqually River drains the southwest slopes of Mount Rainier, a glaciated stratovolcano in the Cascade Range of western Washington. The Nisqually River was impounded behind Alder Dam when the dam was completed in 1945 and formed Alder Lake. This report quantifies the volume of sediment deposited by the Nisqually and Little Nisqually Rivers in their respective deltas in Alder Lake since 1945. Four digital elevation surfaces were generated from historical contour maps from 1945, 1956, and 1985, and a bathymetric survey from 2011. These surfaces were used to compute changes in sediment volume since 1945. Estimates of the volume of sediment deposited in Alder Lake between 1945 and 2011 were focused in three areas: (1) the Nisqually River delta, (2) the main body of Alder Lake, along a 40-meter wide corridor of the pre-dam Nisqually River, and (3) the Little Nisqually River delta. In each of these areas the net deposition over the 66-year period was 42,000,000 ± 4,000,000 cubic meters (m3), 2,000,000 ± 600,000 m3, and 310,000 ± 110,000 m3, respectively. These volumes correspond to annual rates of accumulation of 630,000 ± 60,000 m3/yr, 33,000 ± 9,000 m3/yr, and 4,700 ± 1,600 m3/yr, respectively. The annual sediment yield of the Nisqually (1,100 ± 100 cubic meters per year per square kilometer [(m3/yr)/km2]) and Little Nisqually River basins [70 ± 24 (m3/yr)/km2] provides insight into the yield of two basins with different land cover and geomorphic processes. These estimates suggest that a basin draining a glaciated stratovolcano yields approximately 15 times more sediment than a basin draining forested uplands in the Cascade Range. Given the cumulative net change in sediment volume in the Nisqually River delta in Alder Lake, the total capacity of Alder Lake since 1945 decreased about 3 percent by 1956, 8 percent by 1985, and 15 percent by 2011.

  10. Fate of copper complexes in hydrothermally altered deep-sea sediments from the Central Indian Ocean Basin.

    PubMed

    Chakraborty, Parthasarathi; Sander, Sylvia G; Jayachandran, Saranya; Nath, B Nagender; Nagaraju, G; Chennuri, Kartheek; Vudamala, Krushna; Lathika, N; Mascarenhas-Pereira, Maria Brenda L

    2014-11-01

    The current study aims to understand the speciation and fate of Cu complexes in hydrothermally altered sediments from the Central Indian Ocean Basin and assess the probable impacts of deep-sea mining on speciation of Cu complexes and assess the Cu flux from this sediment to the water column in this area. This study suggests that most of the Cu was strongly associated with different binding sites in Fe-oxide phases of the hydrothermally altered sediments with stabilities higher than that of Cu-EDTA complexes. The speciation of Cu indicates that hydrothermally influenced deep-sea sediments from Central Indian Ocean Basin may not significantly contribute to the global Cu flux. However, increasing lability of Cu-sediment complexes with increasing depth of sediment may increase bioavailability and Cu flux to the global ocean during deep-sea mining.

  11. Paleomagnetic Investigation of Lake Lahontan Sediments and Its Application for Dating Pluvial Events in the Northwestern Great Basin

    NASA Astrophysics Data System (ADS)

    Liddicoat, Joseph C.; Coe, Robert S.

    1997-01-01

    A comparison of paleomagnetic secular variation in sediment of Pleistocene Lake Lahontan in the northwestern Great Basin with secular variation in lake sediment in the Mono Basin, California, indicates that Lake Lahontan was in the valley of the Truckee River between Pyramid Lake and Wadsworth, Nevada, from about 19,000 to 13,000 yr B.P. The secular variation in older Lake Lahontan sediment in the Truckee River valley has the general features of secular variation in middle Pleistocene lacustrine sediments near Rye Patch Dam, Nevada, 125 km to the east. On the basis of field mapping and tephrochronology, the sections of older lacustrine sediments are not coeval. The apparent, but erroneous, correlation of those sediments emphasizes the need for multiple dating methods when paleomagnetic secular variation is used to date stratigraphy.

  12. Sedimentation and water quality in the West Branch Shade River basin, Ohio, 1983-85

    USGS Publications Warehouse

    Oblinger Childress, C. J.; Jones, R.L.

    1988-01-01

    Loss of channel conveyance from deposition of sediment from abandoned surface mines in the West Branch Shade River basin has resulted in frequent flooding. In addition, water quality in the West Branch Shade River and some of its tributaries is typical of streams affected by acid mine drainage. About 938 acres were surfaced mined and abandoned in West Branch Shade River basin. By the end of 1984, about 450 acres were reclaimed. The purpose of this study was to measure the effects of abandoned surface mines and their reclamation on suspended-sediment load, channel cross-section profile, and water quality of West Branch Shade River. Sediment data were collected from June 1983 through September 1985. Daily suspended-sediment samples were collected and continuous streamflow data were recorded at two locations in West Branch Shade River basin and one location in the unmined, East Branch Shade River basin. Water-quality samples were collected three times per year, from June 1983 through July 1986, at four locations in the West Branch Shade River basin and at one location in East Branch Shade River basin and at one location in East Branch Shade River basin. Stream-channel cross sections were surveyed at least twice per year at 10 locations. During the period of study, annual mean suspended-sediment concentration was unchanged for the unmined, East Branch Shade River basin; 0.28 ton per acre-foot of runoff in 1984 and 1985 water years. Annual suspended-sediment concentration, in tons per acre foot, in West Branch Shade River near Harrisonville, from 8.6 in 1984 water year to 0.15 in 1985 water year. In West Branch Shade River near Burlingham, where 48 percent of the abandoned mines were reclaimed by the end of 1984, annual mean suspended-sediment concentration was unchanged (0.5 ton per acre-foot of runoff) in 1984 and 1985 water years and was twice that of the unmined basin. Channel profiles, surveyed at each of the 10 cross sections, indicated scouring at two locations

  13. Sediment supply, tectonic subsidence, and basin-filling patterns across the southwestern South China Sea during Pliocene to recent time

    NASA Astrophysics Data System (ADS)

    Murray, Mychal R.; Dorobek, Steven L.

    Sediment flux to southwestern parts of the South China Sea (SCS) during late Cenozoic time reflects contributions from eastern Tibet, western Borneo, and smaller drainages of central Indochina, Vietnam, the Malay Peninsula, and western Indonesia, although little work has been done to evaluate the significance of each source. Regional seismic-reflection data and well logs from the southwestern SCS were used in this study to evaluate sediment flux and dispersal across the area. Regional seismic-stratigraphic patterns across the southwestern SCS, however, show that Pliocene to Recent sediment accumulation within individual basins was also strongly influenced by long-term changes in tectonic subsidence. More updip basins (e.g., Malay, Cuu Long, and West Natuna basins) became filled after Miocene inversion and an abrupt slowing of tectonic subsidence. Once they became filled, sediment could bypass the updip basins. In contrast, the eastern part of the Nam Con Son Basin (NCSB) has experienced much greater subsidence since early Miocene time and continues to receive sediment that bypasses the updip basins. The paleo-Mekong River and a second depositional system with probable headwaters on the Malay Peninsula began supplying large volumes of sediment to the NCSB during late Miocene and Pliocene time, respectively. Filling of updip basins allowed Pliocene to Recent fluvial and shelf facies to shift progressively eastward across the southwestern SCS. This study shows that Pliocene to Recent sediment dispersal and paleogeographic evolution of the southwestern SCS are as strongly influenced by subsidence patterns as they are by sediment supply from continental drainage systems.

  14. Modelling sediment transport in shallow microtidal basins: comparison with point observations and satellite images

    NASA Astrophysics Data System (ADS)

    Carniello, L.; Defina, A.; D'Alpaos, L.; Volpe, V.; Silvestri, S.; Marani, M.

    2012-12-01

    Field data and mathematical modeling have demonstrated that the morphological evolution of shallow tidal basins is the result of the combined effect of tidal currents and wind waves. A mathematical model has been developed which describes sediment entrainment, transport and deposition due to the combined effect of tidal currents and wind waves in shallow lagoons. The sediment transport model describes sediments by the way of a bi-granular mixtures composed by both cohesive and non-cohesive sediments. Moreover, the model describes the bed evolution and evaluates the variation of bed sediment composition considering also the transition between cohesive and non-cohesive behavior. The model is applied to the Lagoon of Venice (Italy) and the results of different simulations are compared, with good agreement, to a series of in situ point turbidity measurements. In situ point observations provide precise information on the temporal evolution of the local turbidity but can hardly provide information on its spatial variation. Remote sensing techniques can overcome these spatial limitations potentially allowing access to a wider range of scales, and can be applied for the spatially-distributed calibration and validation of sediment transport models. A simplified radiative transfer model to multispectral data from different sensors (Landsat, ASTER and ALOS Avnir) is used to produce suspended sediment concentration maps for the Venice lagoon from available satellite images. These maps are compared with the results of the sediment transport model. Such a comparison also provide a useful tool to investigate the stabilizing effect of benthic vegetation that, otherwise, could be studied only at laboratory and punctual scale.

  15. Fluvial sediment and chemical quality of water in the Little Blue River basin, Nebraska and Kansas

    USGS Publications Warehouse

    Mundorff, J.C.; Waddell, K.M.

    1966-01-01

    The Little Blue River drains about 3,37)0 square miles in south-central Nebraska and north-central Kansas. The uppermost bedrock in the basin is limestone and shale of Permian age and sandstone, shale, and limestone of Cretaceous age. Bedrock is exposed in many places in the lower one-third of the basin but elsewhere is buried beneath a thin to thick mantle of younger sediments, mostly of Quaternary age. These younger sediments are largely fluvial and eolian deposits but also include some glacial till. Consisting in large part of sand and gravel, the fluvial deposits are an important source of ground-water supplies throughout much of the upper two-thirds of the basin. Loess, an eolian deposit of clayey silt, is by far the most widespread surficial deposit. The climate is continental. Temperatures ranging from -38 ? F to 118 ? F have been recorded in the basin. Average annual precipitation as low as 10.31 and as high as 49.32 inches has been recorded. During most years in the period 1956-62, when nearly all the water-quality data were obtained, annual precipitation and annual runoff were greater than normal. Flow-duration data indicate, however, that the flow distribution for the period was near normal. The Little Blue River has the same suspended-sediment characteristics as nearly all unregulated streams in the Great Plains--a wide range in concentrations, low concentrations during low-flow periods, and high concentrations during almost all periods of significant overland runoff. The maximum instantaneous concentration normally occurs many hours before maximum water discharge during any given rise in stage; the maximum daily mean concentration during any given year normally occurs at a moderate stream stage, not during a major flood. Suspended-sediment data for Little Blue River near Deweese, Nebr., which receives drainage from the upstream third of the basin, approximately, show that during the 1!}57-61 water years concentrations of 100 ppm (parts per million) or

  16. Tectonics and sedimentation of Oligo-Miocene Vasquez Formation, Soledad basin, southern California

    SciTech Connect

    Hendrix, E.D.

    1987-05-01

    The nonmarine Oligo-Miocene Vasquez Formation represents the earliest sedimentation within the Soledad basin. Basin analysis of this unit provides important clues to the tectonic regimen during the convergent/transform-margin transition in southern California during the mid-Tertiary. The Vasquez crops out in three separate subbasins or depocenters; from south to north, these are the Vasquez Rocks, Texas Canyon, and Charlie Canyon subbasins. Basaltic-andesitic volcanism and rapid subsidence punctuated the initial rifting event which generated the Vasquez Rocks half-graben and Texas Canyon graben. Small, thick alluvial fans were shed into these two subbasins, with sediment derived via erosion of local plutonic, metamorphic, and volcanic source terranes. A minimum of four discrete uplift events generated development of 250 to 600-m thick, upward-fining alluvial megacycles in both the Vasquez Rocks and Texas Canyon depocenters. In the absence of biostratigraphic control, these allocyclic megasequences provide a tangible means of lithostratigraphic correlation between these separate subbasins. A major uplift and drainage basin reorganization event subsequently modified the Vasquez depositional system, facilitating physical interconnection of the two southern subbasins. The northernmost subbasin, Charlie Canyon, is characterized by a single, thick, upward-coarsening alluvial fan sequence. There are no megacycles or clast suites to suggest interconnection with or evolutionary similarities to the other two depocenters. This sedimentologic uniqueness may support a mid-Tertiary palinspastic reconstruction which places the Charlie Canyon region 80-100 km northwest of its current location. Soledad basin rifting and Vasquez sedimentation are consistent with a tectonic model involving lithospheric extension north of the unstable Mendocino triple junction.

  17. Dissolved sulfide distributions in the water column and sediment pore waters of the Santa Barbara Basin

    USGS Publications Warehouse

    Kuwabara, J.S.; VanGeen, A.; McCorkle, D.C.; Bernhard, J.M.

    1999-01-01

    Dissolved sulfide concentrations in the water column and in sediment pore waters were measured by square-wave voltammetry (nanomolar detection limit) during three cruises to the Santa Barbara Basin in February 1995, November-December 1995, and April 1997. In the water column, sulfide concentrations measured outside the basin averaged 3 ?? 1 nM (n = 28) in the 0 to 600 m depth range. Inside the basin, dissolved sulfides increased to reach values of up to 15 nM at depths >400 m. A suite of box cores and multicores collected at four sites along the northeastern flank of the basin showed considerable range in surficial (400 ??M at 10 cm. Decreases in water-column nitrate below the sill depth indicate nitrate consumption (-55 to -137 ??mole m-2 h-1) similar to nearby Santa Monica Basin. Peaks in pore-water iron concentrations were generally observed between 2 and 5 cm depth with shallowest peaks at the 590 m site. These observations, including observations of the benthic microfauna, suggest that the extent to which the sulfide flux, sustained by elevated pore-water concentrations, reaches the water column may be modulated by the abundance of sulfide-oxidizing bacteria in addition to iron redox and precipitation reactions.

  18. Variability of effective discharge for suspended sediment transport in a large semi-arid river basin

    NASA Astrophysics Data System (ADS)

    Ma, Yuanxu; Huang, He Qing; Xu, Jiongxin; Brierley, Gary J.; Yao, Zhijun

    2010-07-01

    SummaryThe variability of effective discharge is analysed for three geomorphological zones (gullied hilly loess, valley-hill loess and eolian sand) in the Wuding River basin, China, based on mean daily flow discharge and mean daily suspended sediment discharge from 1959 to 1969, a period when human disturbance in this catchment was less intensive. A modified approach to the determination of discharge class intervals is developed, framed in terms of equal arithmetic intervals of the standard deviation S for all the discharges, such as S, 0.75 S, 0.5 S, and 0.25 S. The average flow duration of effective discharge in the river basin ranges primarily from 0.026% to 3.16% in the two loess regions (corresponding to large flood events), and from 18.75% to 91.51% in the eolian sand region (corresponding to low or moderate flows). The average flow duration of effective discharge is significantly influenced by the size of class intervals and by characteristics of the flow and sediment regime. Using the most appropriate class interval of 0.25 S, the average flow duration of effective discharge is about 0.026% in the two loess regions (other than 0.104% at Hengshan), but in the eolian sand region it reaches 24.50% at Yulin and 52.66% at Hanjiamao, respectively. Histograms of suspended sediment transport indicate that there is a bimodal dominant discharge for suspended sediment transport, with one peak in the range of low flows and the other in the range of large floods. Drainage density and specific sediment yields are lower in the eolian sand region, where effective discharge events occur more frequently and suspended sediment concentration is much lower than that carried by events of the same discharge in the loess region. In contrast, drainage density is higher in the two loess regions, where infrequent hyperconcentrated flows generate high specific sediment yields. Effective discharge differs significantly from bankfull discharge across the whole Wuding River basin.

  19. INAA for determination of trace elements in bottom sediments of the Selenga river basin in Mongolia

    NASA Astrophysics Data System (ADS)

    Baljinnyam, N.; Frontasyeva, M. V.; Aleksiayenak, Yu. V.

    2014-03-01

    Instrumental neutron activation analysis (INAA) was used for the determination of major, minor and trace elements in samples of bottom sediments of the inflows of the Selenga river basin to assess the impact of the contamination from the industrial complex Erdenet and other industrial enterprises in Mongolia. A total of 42 elements (Na, Mg, Cl, K, Ca, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr, Rb, Sr, Zr, Nb, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Dy, Tm, Hf, Ta, W, Au, Hg, Th, and U) was determined by combination of conventional and epithermal neutron activation analysis at the IBR-2 reactor, FLNP JINR, Dubna. For the first time such a large set of elements was used for characterization of the bottom sediments as accumulating media which may reflect industrial contamination of the water basin. The concentrations of heavy metals and other trace elements in the samples from three inflows of the Selenga river basin were compared with data from the previous studies. It was shown that the industrial zone of the Erdenet Mining Corporation (EMC) and gold mining zone Zaamar are the sources of strong environmental contamination. The concentrations of Cu and Sb determined in sediment samples of the River Khangal and Govil near the EMC exceed average crustal rock and soil values by factors of 50 and 15, respectively. In the area of the gold mining zone Zaamar concentrations of Au, As, and Sb exceed crustal rock and soil values by factors of 4, 25, and 6, respectively. The relatively high levels of As, V, Zn, V, and Sr in the sediments of the studied rivers are obviously due to the discharges of untreated wastewater of desalination plant, electrical power station, textile industry and mining activities as well as domestic wastewater.

  20. Hydrologic and sediment data collected from selected basins at the Fort Leonard Wood Military Reservation, Missouri--2010-11

    USGS Publications Warehouse

    Richards, Joseph M.; Rydlund, Paul H.; Barr, Miya N.

    2012-01-01

    Commercial and residential development within a basin often increases the amount of impervious area, which changes the natural hydrologic response to storm events by increasing runoff. Land development and disturbance combined with increased runoff from impervious areas potentially can increase sediment transport. At the Fort Leonard Wood Military Reservation in Missouri, there has been an increase in population and construction activities in the recent past, which has initiated an assessment of the hydrology in selected basins. From April 2010 to December 2011, the U.S. Geological Survey, in cooperation with the U.S. Army Maneuver Support Center at the Fort Leonard Wood Military Reservation, collected hydrologic and suspended-sediment concentration data in six basins at Fort Leonard Wood. Storm-sediment concentration, load, and yield varied from basin to basin and from storm to storm. In general, storm-sediment yield, in pounds per square mile per minute, was greatest from Ballard Hollow tributary (06928410) and Dry Creek (06930250), and monthly storm-sediment yield, in tons per square mile, estimates were largest in Ballard Hollow tributary (06928410), East Gate Hollow tributary (06930058), and Dry Creek (06930250). Sediment samples, collected at nine sites, primarily were collected using automatic samplers and augmented with equal-width-increment cross-sectional samples and manually collected samples when necessary. Storm-sediment load and yield were computed from discharge and suspended-sediment concentration data. Monthly storm-sediment yields also were estimated from the total storm discharge and the mean suspended-sediment concentration at each given site.

  1. Distribution of subglacial sediments across the Wilkes Subglacial Basin, East Antarctica

    NASA Astrophysics Data System (ADS)

    Frederick, Bruce C.; Young, Duncan A.; Blankenship, Donald D.; Richter, Thomas G.; Kempf, Scott D.; Ferraccioli, Fausto; Siegert, Martin J.

    2016-04-01

    Topography, sediment distribution, and heat flux are all key boundary conditions governing the dynamics of the East Antarctic Ice Sheet (EAIS). EAIS stability is most at risk in Wilkes Land across vast expanses of marine-based catchments including the 1400 km × 600 km expanse of the Wilkes Subglacial Basin (WSB) region. Data from a recent regional aerogeophysical survey (Investigating the Cryospheric Evolution of the Central Antarctic Plate (ICECAP)/IceBridge) are combined with two historical surveys (Wilkes basin/Transantarctic Mountains System Exploration-Ice-house Earth: Stability or DYNamism? (WISE-ISODYN) and Wilkes Land Transect (WLK)) to improve our understanding of the vast subglacial sedimentary basins impacting WSB ice flow and geomorphology across geologic time. Analyzing a combination of gravity, magnetic and ice-penetrating radar data, we present the first detailed subglacial sedimentary basin model for the WSB that defines distinct northern and southern subbasin isopachs with average sedimentary basin thicknesses of 1144 m ± 179 m and 1623 m ± 254 m, respectively. Notably, more substantial southern subbasin sedimentary deposition in the WSB interior supports a regional Wilkes Land hypothesis that basin-scale ice flow and associated glacial erosion is dictated by tectonic basement structure and the inherited geomorphology of preglacial fluvial networks. Orbital, temperate/polythermal glacial cycles emanating from adjacent alpine highlands during the early Miocene to late Oligocene likely preserved critical paleoclimatic data in subglacial sedimentary strata. Substantially thinner northern WSB subglacial sedimentary deposits are generally restricted to fault-controlled, channelized basins leading to prominent outlet glacier catchments suggesting a more dynamic EAIS during the Pliocene.

  2. Assessing Sediment Yield for Selected Watersheds in the Laurentian Great Lakes Basin Under Future Agricultural Scenarios

    NASA Astrophysics Data System (ADS)

    Shao, Yang; Lunetta, Ross S.; Macpherson, Alexander J.; Luo, Junyan; Chen, Guo

    2013-01-01

    In the Laurentian Great Lakes Basin (GLB), corn acreage has been expanding since 2005 in response to high demand for corn as an ethanol feedstock. This study integrated remote sensing-derived products and the Soil and Water Assessment Tool (SWAT) within a geographic information system (GIS) modeling environment to assess the impacts of cropland change on sediment yield within four selected watersheds in the GLB. The SWAT models were calibrated during a 6 year period (2000-2005), and predicted stream flows were validated. The R 2 values were 0.76, 0.80, 0.72, and 0.81 for the St. Joseph River, the St. Mary River, the Peshtigo River, and the Cattaraugus Creek watersheds, respectively. The corresponding E (Nash and Sutcliffe model efficiency coefficient) values ranged from 0.24 to 0.79. The average annual sediment yields (tons/ha/year) ranged from 0.12 to 4.44 for the baseline (2000 to 2008) condition. Sediment yields were predicted to increase for possible future cropland change scenarios. The first scenario was to convert all "other" agricultural row crop types (i.e., sorghum) to corn fields and switch the current/baseline crop rotation into continuous corn. The average annual sediment yields increased 7-42 % for different watersheds. The second scenario was to further expand the corn planting to hay/pasture fields. The average annual sediment yields increased 33-127 % compared with baseline conditions.

  3. Profile of trace metals accumulation in core sediment from Seine river estuary (docks basin).

    PubMed

    Hamzeh, Mariam; Ouddane, Baghdad; El-Daye, Mirna; Halwani, Jalal

    2013-01-01

    The Seine is one of the most polluted rivers in Europe with respect to potentially harmful elements. It receives effluents from the upstream Paris urban and industrial area, and also local inputs from the heavily industrialized Rouen and Le Havre regions. The present study deals with this environmental topic and the concentrations of Cd, Ni, Pb, Hg, Zn and Cu were determined in sediment cores collected in the docks basin of Rouen harbour in 2008. The intensity of metal pollution during recent decades was evaluated using an enrichment factor (EF) and a geoaccumulation index (Igeo). The results of vertical distribution showed that the metal pollution in the past is much higher than in the surface sediment. Mercury was found to be the heaviest pollutant (with Igeo and EF exceeding 4 and 20, respectively), and Cd and Pb were the second most important pollutants. A slight contamination in Ni was observed with very low Igeo values. To estimate the sediment toxicity, simultaneously extracted metals/acid volatile sulfides ratio (SEM/AVS) was calculated. Low values of the toxicity index SEM/AVS were observed in the core sediments indicating the inexistence of metal potential toxicity. Also the concentrations of these trace metals were lower than the probable effect concentration values reported as consensus-based sediment quality guidelines for fresh water ecosystems. PMID:24191442

  4. Screening of currently used pesticides in water, sediments and biota of the Guadalquivir River Basin (Spain).

    PubMed

    Masiá, Ana; Campo, Julián; Vázquez-Roig, Pablo; Blasco, Cristina; Picó, Yolanda

    2013-12-15

    The occurrence of 50 currently used pesticides and their transformation products in surface and waste waters, sediment and fish in the Guadalquivir River Basin was determined in 2010 and 2011. After selective sample extraction, pesticides were identified and quantified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The contamination profile in water and sediments is marked by the presence of organophosphorus and triazines. Transformation products were even at higher concentrations than parent pesticides. A wider range of pesticides was present in water than in sediments but none of them were detected in fish. The mean concentrations ranged from 0.2 to 13.0 ng/L in water and from 0.1 to 13.2 ng/g d.w. in sediment. The spatial distribution of most pesticides was consistent with the agricultural activities of the area or their urban applications. The waste water treatment plant effluents that impact the river are minor sources for few pesticides but for most of them run-off would be the most important contribution. The temporal distribution showed differences between both sampling campaigns related to the river flow. The low-flow produced a pesticide concentration effect, generating higher levels in water and accumulation in sediments. This forecasts a hazard in future scenarios if the current situation of the climate change and water scarcity evolves to more critical conditions highlighting the need of these monitoring studies. PMID:24140087

  5. Anthropogenic acceleration of sediment accretion in lowland floodplain wetlands, Murray-Darling Basin, Australia

    NASA Astrophysics Data System (ADS)

    Gell, Peter; Fluin, Jennie; Tibby, John; Hancock, Gary; Harrison, Jennifer; Zawadzki, Atun; Haynes, Deborah; Khanum, Syeda; Little, Fiona; Walsh, Brendan

    2009-07-01

    Over the last decade there has been a deliberate focus on the application of paleolimnological research to address issues of sediment flux and water quality change in the wetlands of the Murray-Darling Basin of Australia. This paper reports on the research outcomes on cores collected from sixteen wetlands along the Murrumbidgee-Murray River continuum. In all sixteen wetlands radiometric techniques and exotic pollen biomarkers were used to establish sedimentation rates from the collected cores. Fossil diatom assemblages were used to identify water source and quality changes to the wetlands. The sedimentation rates of all wetlands accelerated after European settlement, as little as two-fold, and as much as eighty times the mean rate through the Late Holocene. Some wetlands completely infilled through the Holocene, while others have rapidly progressed towards a terrestrial state due to accelerated accretion rates. Increasing wetland salinity and turbidity commenced within decades of settlement, contributing to sediment inputs. The sedimentation rate was observed to slow after river regulation in one wetland, but has accelerated recently in others. The complex history of flooding and drying, and wetland salinisation and eutrophication, influence the reliability of models used to establish recent, fine-resolution chronologies with confidence and the capacity to attribute causes to documented effects.

  6. Screening of currently used pesticides in water, sediments and biota of the Guadalquivir River Basin (Spain).

    PubMed

    Masiá, Ana; Campo, Julián; Vázquez-Roig, Pablo; Blasco, Cristina; Picó, Yolanda

    2013-12-15

    The occurrence of 50 currently used pesticides and their transformation products in surface and waste waters, sediment and fish in the Guadalquivir River Basin was determined in 2010 and 2011. After selective sample extraction, pesticides were identified and quantified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The contamination profile in water and sediments is marked by the presence of organophosphorus and triazines. Transformation products were even at higher concentrations than parent pesticides. A wider range of pesticides was present in water than in sediments but none of them were detected in fish. The mean concentrations ranged from 0.2 to 13.0 ng/L in water and from 0.1 to 13.2 ng/g d.w. in sediment. The spatial distribution of most pesticides was consistent with the agricultural activities of the area or their urban applications. The waste water treatment plant effluents that impact the river are minor sources for few pesticides but for most of them run-off would be the most important contribution. The temporal distribution showed differences between both sampling campaigns related to the river flow. The low-flow produced a pesticide concentration effect, generating higher levels in water and accumulation in sediments. This forecasts a hazard in future scenarios if the current situation of the climate change and water scarcity evolves to more critical conditions highlighting the need of these monitoring studies.

  7. Controls on arsenic speciation and solid-phase partitioning in the sediments of a two-basin lake.

    PubMed

    Jay, J A; Blute, N K; Lin, K; Senn, D; Hemond, H F; Durant, J L

    2005-12-01

    Arsenic (As) regeneration from sediments of Spy Pond, a two-basin lake near Boston, MA, continues to result in seasonally elevated As levels despite the several decades that have elapsed since the pond's historical contamination by a pulse input of As. Solid-phase speciation and partitioning of As in the sediments appear to be primary determinants of both potential As regeneration rate and, conversely, the rate at which long-term burial of the pond's As burden will occur. Although iron (Fe) chemistry often controls As speciation in lakes, a higher rate of As regeneration in the south basin, accompanied by the absence of a correlation between regenerated As and Fe in this basin, suggest that additional factors operate to control As cycling in this lake. Solid-phase As speciation was remarkably similar between sediments of the two basins of this lake, about 40% of sedimentary As in upper sediments being in relatively labile (ionically bound and strongly adsorbed) fractions and a larger fraction of As being associated with recalcitrant minerals, likely sulfides. Extraction, X-ray fluorescence, and acid-volatile sulfide data collectively suggest that sedimentary As cycling in both basins is largely controlled by the formation of sulfide minerals. An accounting of the size of sulfur (S) pools supports this conclusion, showing that sufficient S exists in the north basin to control both Fe and As, while the south basin has lower S levels resulting in seasonal accumulation of Fe in the porewater.

  8. Spatial distribution and potential toxicity of polycyclic aromatic hydrocarbons in sediments from Liaohe River Basin, China.

    PubMed

    He, Yan; Meng, Wei; Xu, Jian; Zhang, Yuan; Guo, Changsheng

    2016-03-01

    The distribution and potential toxicity of polycyclic aromatic hydrocarbons (PAHs) in the sediments of Liaohe River Basin were investigated in this study. Total concentrations of 16 PAHs (∑PAH16) ranged from 82.5 to 25374.4 μg/kg averaging 3149.2 μg/kg. Three predominant PAHs were fluoranthene, phenanthrene, and pyrene. In Liao River, two-to-three-ring PAHs were dominant taking up 67.2-92.5% of ∑PAH16, whereas sediments in Daliao River system mainly contained four-to-six-ring PAHs ranging from 47.8 to 83.7%. Both petrogenic and pyrogenic sources contributed to the PAH pollution based on diagnostic ratios. The empirical and mechanistic sediment quality guidelines were used to estimate the toxicity risk of PAHs to benthic organisms. The ∑PAH16 in all sediments were significantly lower than probable effect concentrations (PEC), while ∑PAH16 at nine sites of the Daliao River system were between threshold effect concentrations (TEC) and PEC, suggesting that adverse effects were possible at the nine sites. The only individual PAH was acenaphthene whose concentrations were above PEC at some sites, indicating its potential toxicity. Based upon equilibrium partitioning theory and narcosis model, the obtained toxic units for PAH mixtures at all sites were far less than one, implying that the levels of PAH mixtures were acceptable for the protection of benthic fauna. The two evaluation methods lead to the consistent results that benthic organisms inhabiting in the sediments of Liaohe River Basin have no or low risk of adverse effects resulting from exposure to PAHs. PMID:26915741

  9. Provenance discrimination in surface sediments of the Amerasian Basin (Arctic Ocean) constrained by quantitative mineralogical analyses

    NASA Astrophysics Data System (ADS)

    Bazhenova, E.; Zou, H.; Vogt, C.; Stein, R.; Matthiessen, J.

    2012-04-01

    This study focuses on the determination of potential source areas for the terrigenous material derived from Eurasia and North America to reconstruct the sedimentary environments in the Amerasian Basin of the Arctic Ocean. When compared to the potential source areas in the Arctic Ocean hinterland, spatial variations in bulk mineralogy of surface sediments may provide important information on the trajectories of sea-ice drift and oceanic currents. Investigations are carried out on surface samples recovered from the Mendeleev Ridge and shelves of the East Siberian and the Chukchi seas. Mineralogical analysis was performed on bulk sediments by the X-ray diffraction (XRD) method. Dry powder samples were mixed together with corundum for further quantification of mineral contents. Raw XRD data were processed using the RockJock (Eberl, 2003) and QUAX (Emmermann & Lauterjung, 1990; Vogt, 1997) software to test the consistency of both methods. Additionally, composition of artificial mixtures was determined to test the accuracy of mineral standards. Obtained results are used to identify mineralogical provinces in the surface sediments of the Amerasian Basin. This geographical distribution is also compared to the previously published studies, including the numerous research activities carried out in the Siberian shelf seas in the middle of the 20th century. Bulk mineral composition of surface sediments will be further used for unmixing of the downcore mineralogical records for sediment cores recovered along two transects across the Mendeleev Ridge during the ARK-XXIII/3 Expedition of RV "Polarstern" (for details see Stein et al., 2010). Trends in mineralogical composition will be also compared to the grain-size distribution in order to attribute the provenance changes to different transportation mechanisms in variable sedimentary environments.

  10. Modern sediment yield compared to geologic rates of sediment production in a semi-arid basin, New Mexico: Assessing the human impact

    USGS Publications Warehouse

    Gellis, A.C.; Pavich, M.J.; Bierman, P.R.; Clapp, E.M.; Ellevein, A.; Aby, S.

    2004-01-01

    In the semi-arid Arroyo Chavez basin of New Mexico, a 2.28 km2 sub-basin of the Rio Puerco, we contrasted short-term rates (3 years) of sediment yield measured with sediment traps and dams with long-term, geologic rates (???10 000 years) of sediment production measured using 10Be. Examination of erosion rates at different time-scales provides the opportunity to contrast the human impact on erosion with background or geologic rates of sediment production. Arroyo Chavez is grazed and we were interested in whether differences in erosion rates observed at the two time-scales are due to grazing. The geologic rate of sediment production, 0-27 kg m-2 a -1 is similar to the modern sediment yields measured for geomorphic surfaces including colluvial slopes, gently sloping hillslopes, and the mesa top which ranged from 0.12 to 1.03 kg m -2 a-1. The differences between modern sediment yield and geologic rates of sediment production were most noticeable for the alluvial valley floor, which had modern sediment yields as high as 3.35 kg m-2 a-1. The hydraulic state of the arroyo determines whether the alluvial valley floor is aggrading or degrading. Arroyo Chavez is incised and the alluvial valley floor is gullied and piped and is a source of sediment. The alluvial valley floor is also the portion of the basin most modified by human disturbance including grazing and gas pipeline activity, both of which serve to increase erosion rates. ?? 2004 John Wiley and Sons, Ltd.

  11. Examining the Colonization and Survival of E. coli from Varying Host Sources in Drainage Basin Sediments and Stormwater.

    PubMed

    Curtis, Kyle; Michael Trapp, J

    2016-08-01

    It is widely understood that stormwater drainage has a significant impact on the health of tidal creek systems via regular inputs of runoff from the surrounding watershed. Due to this hydrologic connection, contamination of the upstream drainage basin will have a direct effect on estuaries and tidal creeks that often act as receiving waters. This study focuses on the importance of drainage basin sediments as they enhance the persistence and transport of the fecal indicator bacteria E. coli within a watershed. Experiments presented use microcosm environments with drainage basin sediments and stormwater to investigate E. coli colonization of stagnant waters and to examine the importance of host sources to bacterial survival. A novel method for establishing microcosms using environmental sediments with in situ bacterial populations and sterile overlying waters is used to examine E. coli colonization of the water column in the absence of flow. Colonization of sterile sediment environments also is examined using two common host sources (human and avian). Each experiment uses sediments of varying grain size and organic content to examine the influence of physical characteristics on bacterial prevalence. Results suggest host source of bacteria may be more important to initial bacterial colonization while physical characteristics of drainage basin sediments better explains extended E. coli persistence. Findings also suggest an indirect control of water column bacterial concentration by sediment type and erodibility. PMID:27282707

  12. Examining the Colonization and Survival of E. coli from Varying Host Sources in Drainage Basin Sediments and Stormwater.

    PubMed

    Curtis, Kyle; Michael Trapp, J

    2016-08-01

    It is widely understood that stormwater drainage has a significant impact on the health of tidal creek systems via regular inputs of runoff from the surrounding watershed. Due to this hydrologic connection, contamination of the upstream drainage basin will have a direct effect on estuaries and tidal creeks that often act as receiving waters. This study focuses on the importance of drainage basin sediments as they enhance the persistence and transport of the fecal indicator bacteria E. coli within a watershed. Experiments presented use microcosm environments with drainage basin sediments and stormwater to investigate E. coli colonization of stagnant waters and to examine the importance of host sources to bacterial survival. A novel method for establishing microcosms using environmental sediments with in situ bacterial populations and sterile overlying waters is used to examine E. coli colonization of the water column in the absence of flow. Colonization of sterile sediment environments also is examined using two common host sources (human and avian). Each experiment uses sediments of varying grain size and organic content to examine the influence of physical characteristics on bacterial prevalence. Results suggest host source of bacteria may be more important to initial bacterial colonization while physical characteristics of drainage basin sediments better explains extended E. coli persistence. Findings also suggest an indirect control of water column bacterial concentration by sediment type and erodibility.

  13. Soft-sediment deformation structures interpreted as seismites in the Kolankaya Formation, Denizli Basin (SW Turkey).

    PubMed

    Topal, Savaş; Özkul, Mehmet

    2014-01-01

    The NW-trending Denizli basin of the SW Turkey is one of the neotectonic grabens in the Aegean extensional province. It is bounded by normal faults on both southern and northern margins. The basin is filled by Neogene and Quaternary terrestrial deposits. Late Miocene- Late Pliocene aged Kolankaya formation crops out along the NW trending Karakova uplift in the Denizli basin. It is a typical fluviolacustrine succession that thickens and coarsens upward, comprising poorly consolidated sand, gravelly sand, siltstone and marl. Various soft-sediment deformation structures occur in the formation, especially in fine- to medium grained sands, silts and marls: load structures, flame structures, clastic dikes (sand and gravely-sand dike), disturbed layers, laminated convolute beds, slumps and synsedimentary faulting. The deformation mechanism and driving force for the soft-sediment deformation are related essentially to gravitational instability, dewatering, liquefaction-liquidization, and brittle deformation. Field data and the wide lateral extent of the structures as well as regional geological data show that most of the deformation is related to seismicity and the structures are interpreted as seismites. The existence of seismites in the Kolankaya Formation is evidence for continuing tectonic activity in the study area during the Neogene and is consistent with the occurrence of the paleoearthquakes of magnitude >5.

  14. Soft-Sediment Deformation Structures Interpreted as Seismites in the Kolankaya Formation, Denizli Basin (SW Turkey)

    PubMed Central

    Topal, Savaş; Özkul, Mehmet

    2014-01-01

    The NW-trending Denizli basin of the SW Turkey is one of the neotectonic grabens in the Aegean extensional province. It is bounded by normal faults on both southern and northern margins. The basin is filled by Neogene and Quaternary terrestrial deposits. Late Miocene- Late Pliocene aged Kolankaya formation crops out along the NW trending Karakova uplift in the Denizli basin. It is a typical fluviolacustrine succession that thickens and coarsens upward, comprising poorly consolidated sand, gravelly sand, siltstone and marl. Various soft-sediment deformation structures occur in the formation, especially in fine- to medium grained sands, silts and marls: load structures, flame structures, clastic dikes (sand and gravely-sand dike), disturbed layers, laminated convolute beds, slumps and synsedimentary faulting. The deformation mechanism and driving force for the soft-sediment deformation are related essentially to gravitational instability, dewatering, liquefaction-liquidization, and brittle deformation. Field data and the wide lateral extent of the structures as well as regional geological data show that most of the deformation is related to seismicity and the structures are interpreted as seismites. The existence of seismites in the Kolankaya Formation is evidence for continuing tectonic activity in the study area during the Neogene and is consistent with the occurrence of the paleoearthquakes of magnitude >5. PMID:25152909

  15. The relationship between diagenesis and physical properties of sediments in the Shikoku Basin; Preliminary Results

    NASA Astrophysics Data System (ADS)

    Lee, Gwang Soo; Kim, Gil Young; Kyo Seo, Young; Henry, Pierre; Kanamatsu, Toshiya; Kyaw Thu, Moe; 333 Scientists, Expedition

    2013-04-01

    Integrated Ocean Drilling Program (IODP) Site C0011 is located on the northwest flank of the Kashinosaki Knoll which is the crest of bathymetric high in the Shikoku Basin. In this site, the physical properties of sediment were measured to provide high-resolution data on the bulk physical properties and their downhole variations. All physical property (moisture and density, gamma ray attenuation density, magnetic susceptibility, P-wave velocity, thermal conductivity, vane shear, and electrical resistivity) measurements were made after cores had been imaged by X-ray CT and had equilibrated to room temperature (about 20 °C). From the surface to 50 mbsf, bulk density generally increases and porosity decreases along the downhole. The trend reverses between 50 and 80 mbsf and then remains relatively constant until 240 mbsf. A sharp increase in bulk density (decrease in porosity) occurs between 240 and 270 mbsf, after which a steady consolidation trend continues to the base of the borehole. The dramatic change of physical properties in this section was estimated to be caused by sediment diagenesis which is cementation by the opal-A and opal-CT transformation, because the sediment texture observing from core description and CT scan is unconverted in this section. In the result of sediment texture analysis for total 128 subsamples of Holes C0011C and C0011D, the sediment texture does not show the features related to the change of the physical property between 240 and 270 mbsf, except relatively high mean grain size and sand contents at 235 mbsf. In the quantitative analysis of opal contents for 11 subsamples of Holes C0011C and C0011D, using X-ray diffraction (XRD) and computer software based on Rietveld quantification method, the contents of clay mineral and opal-A are high and also unconverted in all samples, whereas the contents of opal-CT are few. The result of quantitative analysis of opal contents using XRD does not support the sediment diagenesis caused by the opal

  16. Water and sediment transport modeling of a large temporary river basin in Greece.

    PubMed

    Gamvroudis, C; Nikolaidis, N P; Tzoraki, O; Papadoulakis, V; Karalemas, N

    2015-03-01

    The objective of this research was to study the spatial distribution of runoff and sediment transport in a large Mediterranean watershed (Evrotas River Basin) consisting of temporary flow tributaries and high mountain areas and springs by focusing on the collection and use of a variety of data to constrain the model parameters and characterize hydrologic and geophysical processes at various scales. Both monthly and daily discharge data (2004-2011) and monthly sediment concentration data (2010-2011) from an extended monitoring network of 8 sites were used to calibrate and validate the Soil and Water Assessment Tool (SWAT) model. In addition flow desiccation maps showing wet and dry aquatic states obtained during a dry year were used to calibrate the simulation of low flows. Annual measurements of sediment accumulation in two reaches were used to further calibrate the sediment simulation. Model simulation of hydrology and sediment transport was in good agreement with field observations as indicated by a variety of statistical measures used to evaluate the goodness of fit. A water balance was constructed using a 12 year long (2000-2011) simulation. The average precipitation of the basin for this period was estimated to be 903 mm yr(-1). The actual evapotranspiration was 46.9% (424 mm yr(-1)), and the total water yield was 13.4% (121 mm yr(-1)). The remaining 33.4% (302 mm yr(-1)) was the amount of water that was lost through the deep groundwater of Taygetos and Parnonas Mountains to areas outside the watershed and for drinking water demands (6.3%). The results suggest that the catchment has on average significant water surplus to cover drinking water and irrigation demands. However, the situation is different during the dry years, where the majority of the reaches (85% of the river network are perennial and temporary) completely dry up as a result of the limited rainfall and the substantial water abstraction for irrigation purposes. There is a large variability in the

  17. The linkage between longitudinal sediment routing systems and basin types in the northern South China Sea in perspective of source-to-sink

    NASA Astrophysics Data System (ADS)

    Su, Ming; Hsiung, Kan-Hsi; Zhang, Cuimei; Xie, Xinong; Yu, Ho-Shing; Wang, Zhenfeng

    2015-11-01

    Using bathymetric and seismic data, this study describes the morpho-sedimentary features in Qiongdongnan basin and southwest Taiwan collision basin, northern South China Sea and reveals the linkages between sediment routing system and basin types. The modern Central Canyon in the Qiongdongnan basin is located along the rift margin, and subparallel to the shelf-break southeast of Hainan Island. The modern Central Canyon develops along the basin axis (i.e., Xisha Trough) and longitudinally transports sediments eastward which are mainly supplied by northern continental slope. The Penghu Canyon in the southwest Taiwan collision basin is located along the collision boundary parallel to the strike of the adjacent uplifted Taiwan orogen. The Penghu Canyon develops along the tilting basin axis transporting sediments longitudinally southward to the deep-sea basin and Manila Trench. The Penghu Canyon is supplied with sediments from both flank Kaoping and South China Sea slopes where tributary canyons and channels transport sediments down-slope and feed the axial canyon. The certain basin types may be occupied by particular styles of sediment routing system. By comparing the morpho-sedimentary features and basin characteristics associated with the modern Central Canyon to that of the Valencia Channel in NW Mediterranean Sea, the longitudinal sediment routing system in rift basin type can be determined. In contrast, the longitudinal sediment routing systems in collision setting can be represented by the comparable examples of Penghu Canyon in southwest Taiwan collision basin and Markham Canyon in western Solomon Sea. The rift type sediment routing system is characterized by an axial canyon with a single sediment supply from land drainage margin. In contrast, sediment routing system in collision type basins consists of an axial canyon and dual sediment supplies from flank adjacent slopes. The axial canyons in collision basins are more active than that of the rift basin due to

  18. Selected organic compounds and trace elements in streambed sediments and fish tissues, Cook Inlet Basin, Alaska

    USGS Publications Warehouse

    Frenzel, Steven A.

    2000-01-01

    Organochlorines, semivolatile organic compounds (SVOCs), and trace elements were investigated in streambed sediments and fish tissues at selected sites in the Cook Inlet Basin, Alaska, during 1998. At most sites, SVOCs and organochlorine compounds were either not detected or detected at very low concentrations. Chester Creek at Arctic Boulevard at Anchorage, which was the only site sampled with a significant degree of development in the watershed, had elevated levels of many SVOCs in streambed sediment. Coring of sediments from two ponds on Chester Creek confirmed the presence of elevated concentrations of a variety of organic compounds. Moose Creek, a stream with extensive coal deposits in its watershed, had low concentrations of numerous SVOCs in streambed sediment. Three sites located in national parks or in a national wildlife refuge had no detectable concentrations of SVOCs. Trace elements were analyzed in both streambed sediments and tissues of slimy sculpin. The two media provided similar evidence for elevated concentrations of cadmium, lead, and zinc at Chester Creek. In this study, 'probable effect levels '(PELs) were determined from sediments finer than 0.063 millimeters, where concentrations tend to be greatest. Arsenic and chromium concentrations exceeded the PEL at eight and six sites respectively. Zinc exceeded the PEL at one site. Cadmium and copper concentrations were smaller than the PEL at all sites. Mercury concentrations in streambed sediments from the Deshka River were near the PEL, and selenium concentrations at that site also appear to be elevated above background levels. At half the sites where slimy sculpin were sampled, selenium concentrations were at levels that may cause adverse effects in some species.

  19. Perennial-streamflow characteristics related to channel geometry and sediment in Missouri River basin

    USGS Publications Warehouse

    Osterkamp, W.R.; Hedman, E.R.

    1982-01-01

    Geometry, channel-sediment, and discharge data were collected and compiled from 252 streamflow-gaging stations in the Missouri River basin. The sites represent the complete ranges of hydrologic and geologic conditions found in the basin. The data were analyzed by computer to yield equations relating various discharge characteristics to variables of channel geometry and bed and bank material. The equations provide discharge as the dependent variable for the purpose of making estimates of discharge characteristics at ungaged sites. Results show that channel width is best related to variables of discharge, but that reduction of standard errors can be achieved by considering channel-sediment properties, channel gradient, and discharge variability. The channel-material variables do not exert uniform effects on width-discharge relations and, therefore, are considered as sediment-data groups, or stream types, rather than as terms in multiple power-function equations. Relative to streamflow, narrowest channels occur when streams of steady discharge transport sufficient silt and clay to form stable, cohesive banks but have a small tractive load of sand and coarser sizes. Stable channels also are associated with high channel gradients, which cause high channel roughness and bed and bank armouring by coarse particle sizes. The widest, most unstable channels are found with streams that apparently transport of large tractive load of sand sizes. The downstream rates of change of width with discharge reflect these trends, suggesting that a given bed-material load necessitates a minimum width over which the tractive material can be moved. (USGS)

  20. Dams in the Mekong River Basin: Options for Improved Sediment and Fish Passage

    NASA Astrophysics Data System (ADS)

    Wild, T. B.; Loucks, D. P.

    2014-12-01

    The Mekong River and its tributaries comprise one of the most productive fish habitats in the world today. The economic value of the Mekong fishery in Lao PDR, Cambodia and Vietnam is among the highest in the world, providing income and food security to tens of millions of people. However, the construction of multiple dams in the basin will reduce sediment discharge, which will adversely impact nutrient transport and habitat quality and availability, and disrupt fish migration routes. Thus, of considerable interest is the identification of alternatives to the location, design and operation of planned hydropower dams that could improve sediment passage, enable migratory fish passage, and sustain fish production for local use. This paper describes the results of simulation studies designed to identify and evaluate such alternatives, as well as their potential impact on hydropower production. Dam sites in Cambodia and Lao PDR on tributaries and on the mainstream Mekong River will be discussed. Evaluations of sediment management techniques such as flushing, sluicing and bypassing will be discussed. This study is intended to inform decision makers in Cambodia, Lao PDR and Vietnam about potential alternatives to current plans as they prepare decisions regarding the development of over 100 hydropower dams throughout the basin.

  1. Arsenic release by indigenous bacteria Bacillus cereus from aquifer sediments at Datong Basin, northern China

    NASA Astrophysics Data System (ADS)

    Xie, Zuoming; Wang, Yanxin; Duan, Mengyu; Xie, Xianjun; Su, Chunli

    2011-03-01

    Endemic arsenic poisoning due to long-term drinking of high arsenic groundwater has been reported in Datong Basin, northern China. To investigate the effects of microbial activities on arsenic mobilization in contaminated aquifers, Bacillus cereus ( B. cereus) isolated from high arsenic aquifer sediments of the basin was used in our microcosm experiments. The arsenic concentration in the treatment with both bacteria and sodium citrate or glucose had a rapid increase in the first 18 d, and then, it declined. Supplemented with bacteria only, the concentration could increase on the second day. By contrast, the arsenic concentration in the treatment supplemented with sodium citrate or glucose was kept very low. These results indicate that bacterial activities promoted the release of arsenic in the sediments. Bacterial activities also influenced other geochemical parameters of the aqueous phase, such as pH, Eh, and the concentrations of dissolved Fe, Mn, and Al that are important controls on arsenic release. The removal of Fe, Mn, and Al from sediment samples was observed with the presence of B. cereus. The effects of microbial activities on Fe, Mn, and Al release were nearly the same as those on As mobilization. The pH values of the treatments inoculated with bacteria were lower than those without bacteria, still at alkaline levels. With the decrease of Eh values in treatments inoculated with bacteria, the microcosms became more reducing and are thus favorable for arsenic release.

  2. Ratio of basin lag times for runoff and sediment yield processes recorded in various environments

    NASA Astrophysics Data System (ADS)

    Banasik, K.; Hejduk, A.

    2015-03-01

    River basin lag time (LAG), defined as the elapsed time between the occurrence of the centroids of the effective rainfall intensity hyetograph and the storm runoff hydrograph, is an important factor in determining the time to peak and the peak value of the instantaneous unit hydrograph (IUH). In the procedure of predicting a sedimentgraph (suspended sediment load as a function of time), the equivalent parameter is the lag time for the sediment yield (LAGs), which is defined as the elapsed time between the occurrence of the centroids of sediment production during a storm event and the observed sedimentgraph at the gauging station. Data of over 150 events recorded in 11 small river catchments (located in Poland, Germany, UK and USA) with a drainage area of 0.02 km2 to 82 km2 have been analysed to estimate the ratio of LAGs/LAG. The ratio, in majority of cases was smaller than 1, and decreased with increase of river basin slope. Special attention is given to the data collected in a small agricultural catchment and also during snowmelt periods, which is located in central Poland.

  3. Influence of water and sediment supply on the long-term evolution of alluvial fans and deltas: Statistical characterization of basin-filling sedimentation patterns

    NASA Astrophysics Data System (ADS)

    Straub, Kyle M.; Wang, Yinan

    2013-09-01

    temporal and spatial variability of sedimentation, resulting from sediment storage and release and the lateral mobility of sediment transporting flows, imparts fundamental patterns into the stratigraphic record. Recent studies show that paleoenvironmental (allogenic) signals preserved in stratigraphy may be contaminated by internally generated (autogenic) sedimentation patterns; however, it is unclear how the magnitude of autogenic dynamics is related to allogenic forcings. Utilizing statistical methods, we quantify basin-filling trends in three laboratory experiments where input water and sediment flux were varied. We use the compensation index and compensation time scale to estimate the strength of compensation, defined here as the tendency to fill topographic lows faster than would result from random deposit stacking, and to estimate the time scales over which autogenic processes operate. In the experiments, topography of channelized deltas formed by noncohesive sediment was monitored in a basin experiencing temporally and spatially uniform relative subsidence. Each experiment resulted in construction of a stratigraphic package in excess of 25 channel depths thick. We find that compensation strength in the experiments is not influenced by absolute magnitudes of water and sediment flux but does increase as a function of the ratio of water to sediment flux. A compensation time scale, defined as the maximum depth of a system's channels divided by the long-term deposition rate, accurately defines the maximum time scale at which autogenic dynamics occur in all experiments. When applied to field-scale systems, we predict that autogenic dynamics occur out to time scales between 5 and 150 kyr.

  4. Suspended sediment load below open-cast mines for ungauged river basin

    NASA Astrophysics Data System (ADS)

    Kuksina, L.

    2011-12-01

    Placer mines are located in river valleys along river benches or river ancient channels. Frequently the existing mining sites are characterized by low contribution of the environmental technologies. Therefore open-pit mining alters stream hydrology and sediment processes and enhances sediment transport. The most serious environmental consequences of the sediment yield increase occur in the rivers populated by salmon fish community because salmon species prefer clean water with low turbidity. For instance, placer mining located in Kamchatka peninsula (Far East of Russia) which is regarded to be the last global gene pool of wild salmon Oncorhynchus threatens rivers ecosystems significantly. Impact assessment is limited by the hydrological observations scarcity. Gauging network is rare and in many cases whole basins up to 200 km length miss any hydrological data. The main purpose of the work is elaboration of methods for sediment yield estimation in rivers under mining impact and implementation of corresponding calculations. Subjects of the study are rivers of the Vivenka river basin where open-cast platinum mine is situated. It's one of the largest platinum mines in Russian Federation and in the world. This mine is the most well-studied in Kamchatka (research covers a period from 2003 to 2011). Empirical - analytical model of suspended sediment yield estimation was elaborated for rivers draining mine's territories. Sediment delivery at the open-cast mine happens due to the following sediment processes: - erosion in the channel diversions; - soil erosion on the exposed hillsides; - effluent from settling ponds; - mine waste water inflow; - accident mine waste water escape into rivers. Sediment washout caused by erosion was estimated by repeated measurements of the channel profiles in 2003, 2006 and 2008. Estimation of horizontal deformation rates was carried out on the basis of erosion dependence on water discharge rates, slopes and composition of sediments. Soil

  5. Discharge and sediment loads in the Boise River drainage basin, Idaho 1939-40

    USGS Publications Warehouse

    Love, S.K.; Benedict, Paul Charles

    1948-01-01

    The Boise River project is a highly developed agricultural area comprising some 520 square miles of valley and bench lands in southwestern Idaho. Water for irrigation is obtained from the Boise River and its tributaries which are regulated by storage in Arrow Rock and Deer Flat reservoirs. Distribution of water to the farms is effected by 27 principal canals and several small farm laterals which divert directly from the river. The- New York Canal, which is the largest, not only supplies water to smaller canals and farm laterals, but also is used to fill Deer Flat Reservoir near Nampa from which water is furnished to farms in the lower valley. During the past 15 years maintenance costs in a number of those canals have increased due to deposition of sediment in them and in the river channel itself below the mouth of Moore Creek. Interest in determining the runoff and sediment loads from certain areas in the Boise River drainage basin led to an investigation by the Flood Control Coordinating Committee of the Department of Agriculture. Measurements of daily discharge and sediments loads were made by the Geological Survey at 13 stations in the drainage basin during the 18-month period ended June 30, 1940. The stations were on streams in areas having different kinds of vegetative cover and subjected to different kinds of land-use practice. Data obtained during the investigation furnish a basis for certain comparisons of runoff and sediment loads from several areas arid for several periods of time. Runoff measured at stations on the. Boise River near Twin Springs and on Moore Creek near Arrow Rock was smaller during 1939 than during 1940 and was below the average annual runoff for the period of available record. Runoff measured at the other stations on the project also was smaller during 1939 than during 1940 and probably did not exceed the average for the previous 25 years. The sediment loads measured during the spring runoff in 1939 were smaller at most stations than

  6. Development and Interpretation of New Sediment Rating Curve Considering the Effect of Vegetation Cover for Asian Basins

    PubMed Central

    Wang, Jie

    2013-01-01

    Suspended sediment concentration of a river can provide very important perspective on erosion or soil loss of one river basin ecosystem. The changes of land use and land cover, such as deforestation or afforestation, affect sediment yield process of a catchment through changing the hydrological cycle of the area. A sediment rating curve can describe the average relation between discharge and suspended sediment concentration for a certain location. However, the sediment load of a river is likely to be undersimulated from water discharge using least squares regression of log-transformed variables and the sediment rating curve does not consider temporal changes of vegetation cover. The Normalized Difference Vegetation Index (NDVI) can well be used to analyze the status of the vegetation cover well. Thus long time monthly NDVI data was used to detect vegetation change in the past 19 years in this study. Then monthly suspended sediment concentration and discharge from 1988 to 2006 in Laichau station were used to develop one new sediment rating curve and were validated in other Asian basins. The new sediment model can describe the relationship among sediment yield, streamflow, and vegetation cover, which can be the basis for soil conservation and sustainable ecosystem management. PMID:24453795

  7. Quantifying and identifying the sources of fine sediment input in a typical Mongolian river basin, the Kharaa River case study

    NASA Astrophysics Data System (ADS)

    Theuring, Phillip

    2013-04-01

    Mongolia is facing a tremendous change of land-use intensification due to expansions in the agricultural sector, an increase of cattle and livestock and a growth of urban settlements by migration of the rural population to the cities. With most of its area located in a semiarid to arid environment, Mongolia is vulnerable to climatic changes that are expected to lead to higher temperatures and increased evapotranspiration. It is expected that this may lead to unfavorable changes in surface water quality caused by increased nutrients and sediment bound pollutants emissions. Increased fine sediment load is associated with nutrient, heavy metal and pollutant input and therefore affects water quality. Previous studies using radionuclide fallout isotope sediment source fingerprinting investigations identified riverbank erosion as the main source of suspended sediment in the Kharaa River. Erosion susceptibility calculations in combination with suspended sediment observations showed strong seasonal and annual variabilities of sediment input and in-stream transport, and a strong connection of erosional behaviour with land-use.The objective of this study is to quantify the current water quality threats by fine sediment inputs in the 15,000 km2 Kharaa River basin in Northern Mongolia by delineating the sources of the fine sediments and estimating the sediment budget.To identify the spatial distribution of sediment sources within the catchment, more than 1000 samples from the river confluences at the outlet of each sub basin into the main tributary were collected during 5 intensive grab sediment sampling campaigns in 2009-11. The fine sediment fraction (<10μm) has been analysed using geochemical tracer techniques for spatial source identification, based on major elements (e.g. Si, Al, Mg, Fe, Na, K, P) and trace elements (e.g. Ba, Pb, Sr, Zn). The contribution of suspended sediment of each sub basin in the main tributary has been evaluated with help of a mixing model. To

  8. Foraminifers in late Pleistocene-Holocene sediments of the Deryugin Basin of the Sea of Okhotsk

    NASA Astrophysics Data System (ADS)

    Khusid, T. A.; Belyaeva, N. V.; Chekhovskaya, M. P.; Matul, A. G.

    2009-10-01

    The study of foraminifers from sediments accumulated during the last 30 ky revealed their similar distribution in the central and marginal parts of the Deryugin Basin, which implies similar environmental changes throughout this morphological structure. The lack or extreme taxonomical impoverishment of the benthic foraminiferal assemblages during the Last Glacial Maximum indicates a combination of several factors: the significant deterioration of the parameters controlling their bioproductivity in response to the general cooling; the development of anoxic bottom conditions; and, probably, the unfavorable influence of cold barite-methane seeps on the geochemical parameters of the bottom waters. The weaker activity of these seeps in the central part of the basin during the Holocene is evident from some deviations in the structure of the benthic foraminiferal assemblages against the background of their general taxonomic similarity.

  9. Trace elements and organic contaminants in stream sediments from the Red River of the North Basin

    USGS Publications Warehouse

    Brigham, M.E.; Tornes, L.H.

    1996-01-01

    To assess the presence and distribution of a variety of hydro-phobic chemicals in streams in the Red River of the North Basin, bottom sediments were analyzed for trace elements, organochlorines, and polycyclic aromatic hydrocarbons (PAHs). Glaciolacustrine clays and carbonate minerals are common in fine sediments of the region, and can help explain the distribution of many elements. Aluminum (Al), an indicator of glaciolacustrine clay minerals, correlates strongly (r>0.75, p<0.05) with Cr, Co, Fe, La, Li, K, Sc, and Ti; and moderately (0.55Basin, Eu, Nb, Ce, La, Nd, and Ni also have strong correlations with Al. Al correlates negatively with major elements associated with carbonate minerals (Ca, Mg, and inorganic carbon). No significant correlations with Al, Ca, or Mg were observed for As, Pb, Mn, Hg, Se, or Ag, which implies that these elements have different environmental sources or behaviors than glaciolacustrine clays or carbonate minerals. Reduction-oxidation processes may influence Mn distribution. Lead (Pb) and mercury (Hg) are known to be anthropogenically enriched in the environment--their distribution may indicate environmental enrichment in Red River of the North Basin streams. Organochlorines detected are limited to traces of DDT and its metabolites (mostlyp,p'-DDE). Fourteen PAHs, which are constituents of fossil fuels and of combustion byproducts, were detected in at least halfthe sediment samples; pyrene and fluoranthene were detected in about 90 percent of samples. The contaminants detected in this study were present at low levels, likely indicative of diffuse or remote sources; they occur widely in the environment. 

  10. Runoff and sediment production in a Mediterranean basin under two different land uses after forest maintenance

    NASA Astrophysics Data System (ADS)

    Pacheco, Edinson; Rallo, Elena; Úbeda, Xavier; Farguell, Joaquim; Outeiro, Luís

    2013-04-01

    This study analyses the influence of two different land uses on the hydrology of the Vernegà experimental basin between the years 1993 and 2012. The basin is located in the Northeast of the Iberian Peninsula and it is influenced by a Mediterranean climate, with an average annual rainfall of 688 mm. The study of rainfall distribution shows that the majority occurs during autumn and spring, with a 34% and 25% of total annual rainfall respectively. Surface runoff flows from October to June. In this catchment, flash floods may represent 70% of the total water yield, though they only occur 6% of the time. It is important to emphasize that agricultural practices within the study area have been maintained, which is the contrary to the general trend in Mediterranean rural areas. The introduction of forest management practices between 2003 and 2005 has resulted in important hydrological changes in the watershed: Between 2005 and 2012 an increase of the runoff coefficient has been detected. In Bosc the increase represents 38% while in Campàs is 12% in relation with the 1993-2005 period. Campàs yields a greater total runoff than Bosc as a consequence of a greater catchment surface, greater agricultural surface and the existence of forest roads and forest management practices. Part of this phenomenon may be due to the decrease of interception of rainfall and plant biomass in the forested area of the basin. In relation to the sediment yield, it is concentrated during floods (more than 80%) and there is an increase of available sediment after extraordinary events, as it is the case of October 2005 flood, where the total sediment yield was 7 Tkm¯²yr¯¹ and in November 2005 it was 10 Tkm¯²yr¯¹.

  11. Assessment of the environmental conditions of the Sarno river basin (south Italy): a stream sediment approach.

    PubMed

    Albanese, Stefano; Iavazzo, Pietro; Adamo, Paola; Lima, Annamaria; De Vivo, Benedetto

    2013-06-01

    The Sarno river basin covers an area of 500 km(2) collecting the waters of Solofrana and Cavaiola tributaries. Originally it manly represents a source of livelihood for inhabitants by fishing and transporting goods; currently, the Sarno river, still partially used for irrigation, is affected by an extreme environmental degradation as a result of uncontrolled outflow of industrial waste. Within the framework of a wider geochemical prospecting project aiming at characterizing the whole territory of the Campania region, 89 stream sediment samples with a sampling density of 1 sample per 5 km(2) were collected in the river basin and analyzed by means of inductively coupled plasma-mass spectrometry in order to assess the environmental conditions at a regional scale. A GIS-aided technique, based on both the actual distribution of potentially harmful elements and their regional background values, was used to generate the maps of the contamination factors and of the contamination degrees for As, Cd, Cr, Cu, Hg, Pb and Zn. Furthermore, a factor analysis was performed to assess the nature and the extent of contamination sources for the river sediments. Results showed that the Sarno river basin could be divided in two "environmental status" units: one, low contaminated, corresponding to the hilly and mountain areas, and the second, from moderately to very highly contaminated, corresponding to the economically developed areas of the valley floor characterized by a high population density. This work was developed within a project that aims to investigate the relationships between environmental pollution and human health by analyzing environmental media (stream sediments, water, soil and vegetation) together with human hair of resident population. In this context, the spatial correlation between the extremely compromised environmental conditions of developed areas and the incidence rate of liver cancer in the same area was also explored posing the need of a careful costs

  12. Annual suspended sediment and trace element fluxes in the Mississippi, Columbia, Colorado, and Rio Grande drainage basins

    USGS Publications Warehouse

    Horowitz, A.J.; Elrick, K.A.; Smith, J.J.

    2001-01-01

    Suspended sediment, sediment-associated, total trace element, phosphorus (P), and total organic carbon (TOC) fluxes were determined for the Mississippi, Columbia, Rio Grande, and Colorado Basins for the study period (the 1996, 1997, and 1998 water years) as part of the US Geological Survey's redesigned National Stream Quality Accounting Network (NASQAN) programme. The majority (??? 70%) of Cu, Zn, Cr, Ni, Ba, P, As, Fe, Mn, and Al are transported in association with suspended sediment; Sr transport seems dominated by the dissolved phase, whereas the transport of Li and TOC seems to be divided equally between both phases. Average dissolved trace element levels are markedly lower than reported during the original NASQAN programme; this seems due to the use of 'clean' sampling, processing, and analytical techniques rather than to improvements in water quality. Partitioning between sediment and water for Ag, Pb, Cd, Cr, Co, V, Be, As, Sb, Hg, and Ti could not be estimated due to a lack of detectable dissolved concentrations in most samples. Elevated suspended sediment-associated Zn levels were detected in the Ohio River Basin and elevated Hg levels were detected in the Tennessee River, the former may affect the mainstem Mississippi River, whereas the latter probably do not. Sediment-associated concentrations of Ag, Cu, Pb, Zn, Cd, Cr, Co, Ba, Mo, Sb, Hg, and Fe are markedly elevated in the upper Columbia Basin, and appear to be detectable (Zn, Cd) as far downstream as the middle of the basin. These elevated concentrations seem to result from mining and/or mining-related activities. Consistently detectable concentrations of dissolved Se were found only in the Colorado River Basin. Calculated average annual suspended sediment fluxes at the mouths of the Mississippi and Rio Grande Basins were below, whereas those for the Columbia and Colorado Basins were above previously published annual values. Downstream suspended sediment-associated and total trace element fluxes

  13. Rift border system: The interplay between tectonics and sedimentation in the Reconcavo basin, northeastern Brazil

    SciTech Connect

    Magnavita, L.P.; Silva, T.F. da

    1995-11-01

    A geometric and depositional model is proposed to explain the tectonic and sedimentary evolution of the main border of the Reconcavo basin. The architecture of the rift margin is characterized by a rift border system constituted by (1) a master fault, (2) a step, and (3) a clastic wedge. This footwall-derived clastic wedge is interpreted as alluvial fans and fan deltas composed of conglomerates that interfinger with hanging-wall strata. The analysis of the vertical distribution of coarse-grained components of this wedge suggests that its composition is geographically controlled, and no regular inverted stratigraphy is commonly described for this type of succession. During an initial lacustrine phase, turbidites accumulated farther from and parallel to the rift margin. The mapping of marker beds that bound these lacustrine turbidite deposits may be used to infer major periods of clastic influx and, therefore, to correlate with periods of fault-related subsidence or climatic fluctuations in the depositional basin and erosion of the sediment source area. Periods of limited back-faulting and basin expansion toward the main border are distinguished through patterns of progradation and aggradation indicating progressive retreat of the rift border and younging; in the footwall direction. The overall evolution of the rift border seems to be related to extension, block rotation, hanging-wall subsidence, and footwall uplift associated with the initial master fault, with limited propagation of faults away from the basin into the footwall.

  14. Linking Late Pleistocene alpine glacial erosion and continental margin sedimentation: Insights from 40Ar/39Ar dating of silt-sized sediment, Canterbury Basin, New Zealand

    NASA Astrophysics Data System (ADS)

    Villaseñor, Tania; Jaeger, John M.; Foster, David A.

    2016-01-01

    Quaternary climatic and eustatic cycles in mid-latitude regions have led to more extensive alpine glaciations and continental shelf progradation, respectively. However, the glacial influence on sediment fluxes to the ocean creating continental margin strata is poorly documented. This contribution analyzes the provenance of fine sediment accumulating on the continental shelf during the Late Pleistocene to evaluate the influence of glacial cycles on sediment erosion and routing to the continental shelf. Taking advantage of the contrasting bedrock ages exposed across the Southern Alps, New Zealand, we perform 40Ar/39Ar incremental heating on the bulk silt-size sediment from three drill sites of IODP Expedition 317, Canterbury Basin, New Zealand. The results suggest that a large proportion of sediment accumulating on the continental shelf results from erosion within the Main Divide fault zone of the Southern Alps. Sediment 40Ar/39Ar age fluctuations over this time period suggest that bedrock with various 40Ar/39Ar cooling ages has been differentially eroded in the upper Waitaki River catchment and mixed in the Waitaki-Canterbury sediment-routing system. Across-shelf variations in sediment 40Ar/39Ar age reflect changing modes of sediment dispersal on the continental shelf. Fluvial material, likely derived from the main drainage divide zone, preferentially accumulates in the middle continental shelf, whereas material representing erosion of older bedrock (Torlesse Terrane), located lower in the drainage basin, is dispersed uniformly across the shelf. The age signature of the muddy sediment accumulating on the continental shelf reflects Late Pleistocene landscape evolution of the Southern Alps and its influence on sediment dispersal to the continental shelf.

  15. Distribution of trace elements in sediment and soil from river Vardar Basin, Macedonia/Greece.

    PubMed

    Popov, Stanko Ilić; Stafilov, Trajče; Šajn, Robert; Tănăselia, Claudiu

    2016-01-01

    A systematic study was carried out to investigate the distribution of 59 elements in the sediment and soil samples collected from the river Vardar (Republic of Macedonia and Greece) and its major tributaries. The samples were collected from 28 sampling sites. Analyses were performed by inductively coupled plasma-mass spectrometry. R-mode factor analysis (FA) was used to identify and characterise element associations. Seven associations of elements were determined by the method of multivariate statistics. Every factor (Factors 1-3 and 6 and 7 as geogenic and Factors 4 and 5 as anthropogenic associations of elements) are examined and explained separately. The distribution of various elements showed that there is a presence of anthropogenic elements (Ag, Cd, Cu, Ge, Pb, Sn and Zn) introduced in the river sediments and soils from the mining, metallurgical, industrial and agricultural activities in Vardar River Basin, which covers most of the Republic of Macedonia and Central-northern part of Greece. PMID:26422060

  16. Soil conservation and the reduction of erosion and sedimentation in the Coon Creek basin, Wisconsin

    USGS Publications Warehouse

    Trimble, S.W.; Lund, S.W.

    1982-01-01

    The Coon Creek basin, in the Driftless Area of Wisconsin, has been strikingly transformed by soil conservation measures since the 1930's. Comparison of sheet and rill erosion by use of the Universal Soil Loss Equation, shows 1975 erosion rates on upland fields to be about one-fourth those of 1934. Average annual sedimentation accumulation in small reservoirs declined from about 5,000 megagrams per square kilometer in 1936-45 to about 50 megagrams per square kilometer in 1962-75. Analysis of deposition in tributary valleys suggests that annual rates declined from about 3,700 megagrams per square kilometer in the 1930 's to about 35-70 megagrams per square kilometer in recent years. These reductions in erosion and sedimentation are due principally to improvements in land management and, to a lesser degree, to changes in land use. (USGS)

  17. Evolution of biomarkers in early diagenesis: organic geochemistry of Quaternary sediment in the Chiawobao basin

    NASA Astrophysics Data System (ADS)

    Mingju, Xiang; Jiyang, Shi; Zhiqing, Hong; Qizhong, Wen

    The Quaternary sediments of the Chiawobao basin in the Xinjiang Autonomous Region, represented by cores from drill wells, were studied to understand their amino acids, fatty acids, sterols, steranes, terpanes and alkanes. As a result, it has been recognized that the organic matter in sediments were mainly derived from zooplankton and phytoplankton, as well as high plnat debris. During early diagenesis, the amino acid content had dropped sharply, and n-alkane with a low molecular weight had been generated from fatty acids through decarboxylic function, whereas sterols seemed to be more stable as compared with fatty acids, and the odd carbon preference in n-alkanes may have remained until the late diagenesis stage. The results from this study have provided valuable data for understanding the evolution of organic matter at the early diagenesis stage.

  18. Distribution of trace elements in sediment and soil from river Vardar Basin, Macedonia/Greece.

    PubMed

    Popov, Stanko Ilić; Stafilov, Trajče; Šajn, Robert; Tănăselia, Claudiu

    2016-01-01

    A systematic study was carried out to investigate the distribution of 59 elements in the sediment and soil samples collected from the river Vardar (Republic of Macedonia and Greece) and its major tributaries. The samples were collected from 28 sampling sites. Analyses were performed by inductively coupled plasma-mass spectrometry. R-mode factor analysis (FA) was used to identify and characterise element associations. Seven associations of elements were determined by the method of multivariate statistics. Every factor (Factors 1-3 and 6 and 7 as geogenic and Factors 4 and 5 as anthropogenic associations of elements) are examined and explained separately. The distribution of various elements showed that there is a presence of anthropogenic elements (Ag, Cd, Cu, Ge, Pb, Sn and Zn) introduced in the river sediments and soils from the mining, metallurgical, industrial and agricultural activities in Vardar River Basin, which covers most of the Republic of Macedonia and Central-northern part of Greece.

  19. Priority-pollutant trace elements in streambed sediments of the Cook Inlet basin, Alaska, 1998-2000

    USGS Publications Warehouse

    Frenzel, Steven A.

    2002-01-01

    Trace element concentrations in 48 streambed sediment samples collected at 47 sites in the Cook Inlet Basin, Alaska, were compared to concentrations from studies in the conterminous United States using identical methods and to Probable Effect Concentrations. Concentrations of arsenic, chromium, mercury, and nickel in the 0.063-mm size fraction of streambed sediments from the Cook Inlet Basin were elevated relative to reference sites in the conterminous United States. Concentrations of cadmium, lead, and zinc were highest at the most urbanized site in Anchorage and at two sites downstream from an ore body in Lake Clark National Park and Preserve. At least 35 percent of the 48 samples collected in the Cook Inlet Basin exceeded the Probable Effect Concentration for arsenic, chromium, or nickel. More than 50 percent of the samples were considered to have low potential toxicity for cadmium, lead, mercury, nickel, selenium, and zinc. A Probable Effect Concentration quotient that reflects the combined toxicity of arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc was exceeded in 44 percent of the samples from the Cook Inlet Basin. The potential toxicity was high in the Denali and Lake Clark National Parks and Preserves where organic carbon concentrations in streambed sediments were low. However, potential toxicity results should be considered in context with the very small amounts of fine-grained sediment present in the streambed sediments of the Cook Inlet Basin.

  20. Calculating Hillslope Contributions to River Basin Sediment Yield Using Observations in Small Watersheds and an Index-based Model

    NASA Astrophysics Data System (ADS)

    Kinner, D. A.; Kinner, D. A.; Stallard, R. F.

    2001-12-01

    Detailed observations of hillslope erosion are generally made in < 1 km2 watersheds to gain a process-level understanding in a given geomorphic setting. In addressing sediment and nutrient source-to-sink questions, a broader, river basin ( > 1000 km2) view of erosion and deposition is necessary to incorporate the geographic variability in the factors controlling sediment mobilization and storage. At the river basin scale, floodplain and reservoir storage become significant in sediment budgets. In this study, we used observations from USDA experimental watersheds to constrain an index-based model of hillslope erosion for the 7270 km2 Nishnabotna River Basin in the agricultural, loess-mantled region of southwest Iowa. Spatial and time-series measurements from two watersheds near Treynor, Iowa were used to calibrate the model for the row-cropped fields of the basin. By modeling rainfall events over an 18-year period, model error was quantified. We then applied the model to calculate basin-wide hillslope erosion and colluvial storage. Soil maps and the National Land-Cover Dataset were used to estimate model soil erodibility and land-use factors. By comparing modeled hillslope yields with observed basin sediment yields, we calculated that hillslope contributions to sediment yield were < 50% for the period 1974-1992. A major uncertainty in modeling is the percentage of basin area that is terraced. We will use the isotopes Cs137 and Pb210 to distinguish bank (isotope-poor) and hillslope (isotope-rich) contributions in flood plain deposits. This independent estimate of the relative hillslope contribution to sediment yield will reduce modeling uncertainty.

  1. Soil disturbance/restoration effects on stream sediment loading in the Tahoe Basin--detection monitoring.

    PubMed

    Grismer, M E

    2014-07-01

    Quantifying the relative impacts of soil restoration or disturbance on watershed daily sediment and nutrients loads is essential towards assessing the actual costs/benefits of the land management. Such quantification requires stream monitoring programs capable of detecting changes in land-use or soil functional and erosive area "connectivity" conditions across the watershed. Previously, use of a local-scale, field-data based runoff and erosion model for three Lake Tahoe west-shore watersheds as a detection monitoring "proof of concept" suggested that analyses of midrange average daily flows can reveal sediment load reductions of relatively small watershed fractional areas (∼5 %) of restored soil function within a few years of treatment. Developing such an effective stream monitoring program is considered for tributaries on the west shore of the Lake Tahoe Basin using continuous (15-min) stream monitoring information from Ward (2,521 ha), Blackwood (2,886 ha), and the Homewood (260 ha, HMR) Creek watersheds. The continuous total suspended sediment (TSS) and discharge monitoring confirmed the hysteretic TSS concentration-flowrate relationship associated with the daily and seasonal spring snowmelt hydrographs at all three creeks. Using the complete dataset, daily loads estimated from 1-h sampling periods during the day indicated that the optimal sampling hours were in the afternoon during the rising limb of the spring snowmelt hydrograph, an observation likely to apply across the Sierra Nevada and other snowmelt driven watersheds. Measured rising limb sediment loads were used to determine if soils restoration efforts (e.g., dirt road removal, ski run rehabilitation) at the HMR creek watershed reduced sediment loads between 2010 and 2011. A nearly 1.5-fold decrease in sediment yields (kg/ha per m(3)/s flow) was found suggesting that this focused monitoring approach may be useful towards development of TMDL "crediting" tools. Further monitoring is needed to verify

  2. Soil disturbance/restoration effects on stream sediment loading in the Tahoe Basin--detection monitoring.

    PubMed

    Grismer, M E

    2014-07-01

    Quantifying the relative impacts of soil restoration or disturbance on watershed daily sediment and nutrients loads is essential towards assessing the actual costs/benefits of the land management. Such quantification requires stream monitoring programs capable of detecting changes in land-use or soil functional and erosive area "connectivity" conditions across the watershed. Previously, use of a local-scale, field-data based runoff and erosion model for three Lake Tahoe west-shore watersheds as a detection monitoring "proof of concept" suggested that analyses of midrange average daily flows can reveal sediment load reductions of relatively small watershed fractional areas (∼5 %) of restored soil function within a few years of treatment. Developing such an effective stream monitoring program is considered for tributaries on the west shore of the Lake Tahoe Basin using continuous (15-min) stream monitoring information from Ward (2,521 ha), Blackwood (2,886 ha), and the Homewood (260 ha, HMR) Creek watersheds. The continuous total suspended sediment (TSS) and discharge monitoring confirmed the hysteretic TSS concentration-flowrate relationship associated with the daily and seasonal spring snowmelt hydrographs at all three creeks. Using the complete dataset, daily loads estimated from 1-h sampling periods during the day indicated that the optimal sampling hours were in the afternoon during the rising limb of the spring snowmelt hydrograph, an observation likely to apply across the Sierra Nevada and other snowmelt driven watersheds. Measured rising limb sediment loads were used to determine if soils restoration efforts (e.g., dirt road removal, ski run rehabilitation) at the HMR creek watershed reduced sediment loads between 2010 and 2011. A nearly 1.5-fold decrease in sediment yields (kg/ha per m(3)/s flow) was found suggesting that this focused monitoring approach may be useful towards development of TMDL "crediting" tools. Further monitoring is needed to verify

  3. Microbial diversity of hydrothermal sediments in the Guaymas Basin: evidence for anaerobic methanotrophic communities.

    PubMed

    Teske, Andreas; Hinrichs, Kai-Uwe; Edgcomb, Virginia; de Vera Gomez, Alvin; Kysela, David; Sylva, Sean P; Sogin, Mitchell L; Jannasch, Holger W

    2002-04-01

    Microbial communities in hydrothermally active sediments of the Guaymas Basin (Gulf of California, Mexico) were studied by using 16S rRNA sequencing and carbon isotopic analysis of archaeal and bacterial lipids. The Guaymas sediments harbored uncultured euryarchaeota of two distinct phylogenetic lineages within the anaerobic methane oxidation 1 (ANME-1) group, ANME-1a and ANME-1b, and of the ANME-2c lineage within the Methanosarcinales, both previously assigned to the methanotrophic archaea. The archaeal lipids in the Guaymas Basin sediments included archaeol, diagnostic for nonthermophilic euryarchaeota, and sn-2-hydroxyarchaeol, with the latter compound being particularly abundant in cultured members of the Methanosarcinales. The concentrations of these compounds were among the highest observed so far in studies of methane seep environments. The delta-(13)C values of these lipids (delta-(13)C = -89 to -58 per thousand) indicate an origin from anaerobic methanotrophic archaea. This molecular-isotopic signature was found not only in samples that yielded predominantly ANME-2 clones but also in samples that yielded exclusively ANME-1 clones. ANME-1 archaea therefore remain strong candidates for mediation of the anaerobic oxidation of methane. Based on 16S rRNA data, the Guaymas sediments harbor phylogenetically diverse bacterial populations, which show considerable overlap with bacterial populations of geothermal habitats and natural or anthropogenic hydrocarbon-rich sites. Consistent with earlier observations, our combined evidence from bacterial phylogeny and molecular-isotopic data indicates an important role of some novel deeply branching bacteria in anaerobic methanotrophy. Anaerobic methane oxidation likely represents a significant and widely occurring process in the trophic ecology of methane-rich hydrothermal vents. This study stresses a high diversity among communities capable of anaerobic oxidation of methane.

  4. Large-scale patterns of recent sedimentation along the Cayman Troughpull-apart basin, Caribbean Sea

    SciTech Connect

    Debalko, D.; Mann, P. )

    1990-05-01

    The North American-Caribbean plate boundary zone consists of a broad zone of active strike-slip deformation that extends 3,200 km from Middle America to the Lesser Antilles. An 1,100-km-long, 100-km-wide pull-apart basin the Cayman Trough is the dominant structural element of the submerged central part of the plate boundary zone between Jamaica and Honduras. In order to investigate large-scale patterns of recent sedimentation in a fully marine pull-apart setting, the authors surveyed a 90,000-km{sup 2} area along the southern edge of the Cayman Trough using SeaMARC II side-scan sonar, 3.5 KHz, and digital single-channel reflection techniques. These data allow them to divide the southern margin of the Cayman Trough pull-apart into three provinces of recent sedimentation: (1) an eastern terrigenous province characterized by straight short canyon systems (average 1-3 km wide and 10-15 km long) and associated small, lobate fans; canyon-fan systems are sourced by clastic spillover from filled borderland-type basins and by erosion of emergent fault-block islands; (2) a central carbonate province characterized by periplatform carbonate detritus fringing four isolated carbonate banks which collectively make up the Nicaraguan Rise; canyon systems (1-3 km wide, 15-80 km long) are highly meandering when unfaulted and straight when faulted; and (3) an eastern carbonate and terrigenous province characterized by both carbonate sediments shed off the easternmost bank of the Nicaraguan Rise bank and by terrigenous sediment derived from Jamaica.

  5. Microbial Diversity of Hydrothermal Sediments in the Guaymas Basin: Evidence for Anaerobic Methanotrophic Communities†

    PubMed Central

    Teske, Andreas; Hinrichs, Kai-Uwe; Edgcomb, Virginia; de Vera Gomez, Alvin; Kysela, David; Sylva, Sean P.; Sogin, Mitchell L.; Jannasch, Holger W.

    2002-01-01

    Microbial communities in hydrothermally active sediments of the Guaymas Basin (Gulf of California, Mexico) were studied by using 16S rRNA sequencing and carbon isotopic analysis of archaeal and bacterial lipids. The Guaymas sediments harbored uncultured euryarchaeota of two distinct phylogenetic lineages within the anaerobic methane oxidation 1 (ANME-1) group, ANME-1a and ANME-1b, and of the ANME-2c lineage within the Methanosarcinales, both previously assigned to the methanotrophic archaea. The archaeal lipids in the Guaymas Basin sediments included archaeol, diagnostic for nonthermophilic euryarchaeota, and sn-2-hydroxyarchaeol, with the latter compound being particularly abundant in cultured members of the Methanosarcinales. The concentrations of these compounds were among the highest observed so far in studies of methane seep environments. The δ-13C values of these lipids (δ-13C = −89 to −58‰) indicate an origin from anaerobic methanotrophic archaea. This molecular-isotopic signature was found not only in samples that yielded predominantly ANME-2 clones but also in samples that yielded exclusively ANME-1 clones. ANME-1 archaea therefore remain strong candidates for mediation of the anaerobic oxidation of methane. Based on 16S rRNA data, the Guaymas sediments harbor phylogenetically diverse bacterial populations, which show considerable overlap with bacterial populations of geothermal habitats and natural or anthropogenic hydrocarbon-rich sites. Consistent with earlier observations, our combined evidence from bacterial phylogeny and molecular-isotopic data indicates an important role of some novel deeply branching bacteria in anaerobic methanotrophy. Anaerobic methane oxidation likely represents a significant and widely occurring process in the trophic ecology of methane-rich hydrothermal vents. This study stresses a high diversity among communities capable of anaerobic oxidation of methane. PMID:11916723

  6. Variations in trace element geochemistry in the Seine River Basin based on floodplain deposits and bed sediments

    USGS Publications Warehouse

    Horowitz, A.J.; Meybeck, Michel; Idlafkih, Z.; Biger, E.

    1999-01-01

    Between 1990 and 1995 a series of bed sediment, suspended sediment and fresh floodplain samples were collected within the Seine River Basin, in France, to evaluate variations in trace element geochemistry. Average background trace element levels for the basin were determined from the collection and subsequent analyses of bed sediment samples from small rural watersheds and from a prehistoric (5000 BP) site in Paris. Concentrations are relatively low, and similar to those observed for fine-grained bed sediments from unaffected areas in the United States and Canada. However, the concentrations are somewhat higher than the reference levels presently adopted by French water authorities for areas north of the Seine Basin, which have similar bedrock lithologies. Downstream trace element variations were monitored in 1994 and 1995 using fresh surficial floodplain samples that were collected either as dried deposits a few days after peak discharge, or immediately after peak discharge (under ??? 30 cm of water). Chemical comparisons between fresh floodplain deposits, and actual suspended sediments collected during flood events, indicate that, with some caveats, the former can be used as surrogates for the latter. The floodplain sediment chemical data indicate that within the Seine Basin, from the relatively unaffected headwaters through heavily affected urban streams, trace element concentrations vary by as much as three orders of magnitude. These trace element changes appear to be the result of both increases in population as well as concomitant increases in industrial activity. This article is a US government work and is in the public domain in the United States.

  7. Beyond Colorado's Front Range - A new look at Laramide basin subsidence, sedimentation, and deformation in north-central Colorado

    USGS Publications Warehouse

    Cole, James C.; Trexler, James H.; Cashman, Patricia H.; Miller, Ian M.; Shroba, Ralph R.; Cosca, Michael A.; Workman, Jeremiah B.

    2010-01-01

    This field trip highlights recent research into the Laramide uplift, erosion, and sedimentation on the western side of the northern Colorado Front Range. The Laramide history of the North Park?Middle Park basin (designated the Colorado Headwaters Basin in this paper) is distinctly different from that of the Denver basin on the eastern flank of the range. The Denver basin stratigraphy records the transition from Late Cretaceous marine shale to recessional shoreline sandstones to continental, fluvial, marsh, and coal mires environments, followed by orogenic sediments that span the K-T boundary. Upper Cretaceous and Paleogene strata in the Denver basin consist of two mega-fan complexes that are separated by a 9 million-year interval of erosion/non-deposition between about 63 and 54 Ma. In contrast, the marine shale unit on the western flank of the Front Range was deeply eroded over most of the area of the Colorado Headwaters Basin (approximately one km removed) prior to any orogenic sediment accumulation. New 40Ar-39Ar ages indicate the oldest sediments on the western flank of the Front Range were as young as about 61 Ma. They comprise the Windy Gap Volcanic Member of the Middle Park Formation, which consists of coarse, immature volcanic conglomerates derived from nearby alkalic-mafic volcanic edifices that were forming at about 65?61 Ma. Clasts of Proterozoic granite, pegmatite, and gneiss (eroded from the uplifted core of the Front Range) seem to arrive in the Colorado Headwaters Basin at different times in different places, but they become dominant in arkosic sandstones and conglomerates about one km above the base of the Colorado Headwaters Basin section. Paleocurrent trends suggest the southern end of the Colorado Headwaters Basin was structurally closed because all fluvial deposits show a northward component of transport. Lacustrine depositional environments are indicated by various sedimentological features in several sections within the >3 km of sediment

  8. Estimation of Sediment Sources Using Selected Chemical Tracers in the Perry Lake and Lake Wabaunsee Basins, Northeast Kansas

    USGS Publications Warehouse

    Juracek, Kyle E.; Ziegler, Andrew C.

    2007-01-01

    In Kansas and nationally, stream and lake sediment is a primary concern as related to several important issues including water quality and reservoir water-storage capacity. The ability to achieve meaningful decreases in sediment loads to reservoirs requires a determination of the relative importance of sediment sources within the contributing basins. To investigate sources of sediment within the Perry Lake and Lake Wabaunsee Basins of northeast Kansas, representative samples of channel-bank sources, surface-soil sources (cropland and grassland), and reservoir bottom sediment were collected, analyzed, and compared. Subbasins sampled within the Perry Lake Basin included Atchison County Lake, Banner Creek Reservoir, Gregg Creek, Mission Lake, and Walnut Creek. The samples were sieved to isolate the less than 63-micron fraction (that is, the silt and clay) and analyzed for selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, and the radionuclide cesium-137 (137Cs). To determine which of the 30 constituents provided the best ability to discriminate between channel-bank and surface-soil sources in the two basins, four selection criteria were used. To be selected, it was required that the candidate constituent (1) was detectable, (2) had concentrations or activities that varied substantially and consistently between the sources, (3) had concentration or activity ranges that did not overlap between the sources, and (4) had concentration or activity differences between the sources that were statistically significant. On the basis of the four selection criteria, total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), and 137Cs were selected. Of the four selected constituents, 137Cs likely is the most reliable indicator of sediment source because it is known to be conservative in the environment. Trace elements were not selected because concentrations in the channel-bank and surface-soil sources generally were

  9. Sediment yield along the Andes: continental budget, regional variations, and comparisons with other basins from orogenic mountain belts

    NASA Astrophysics Data System (ADS)

    Latrubesse, Edgardo M.; Restrepo, Juan D.

    2014-07-01

    We assess the sediment yield at 119 gauging stations distributed from Colombia to Patagonia, covering the different morphotectonic and morphoclimatic settings of the Andes. The most productive areas are the Meta River basin within the northern Andes and the Bolivian and northern Argentina-Chaco systems, which produce an average of 3345, 4909 and 2654 t km2 y- 1 of sediment, respectively. The rivers of the northern and central Andes (excluding the Pacific watersheds of Peru, northern Chile, and central Argentina) have a weighted mean sediment yield of 2045 t km- 2 y- 1 and produce 2.25 GTy- 1 of total sediment. A major constraint estimating the Andean continental budget of sediment yield lies in the lack of gauging data for the Peruvian region. Using the available gauge stations, the regional sediment yield appears underestimated. Assuming a higher value of sediment yield for the Peruvian Andes, the total budget for the whole central Andes could range between 2.57 GT y- 1 and 3.44 GT y- 1. A minimum of ~ 0.55 GT y- 1 and a probable maximum of ~ 1.74 GT y- 1 of sediment are deposited in the intramontane and surrounding proximal sedimentary basins. The magnitude of sediment yield in the Andes is comparable to other rivers draining orogenic belts around the world.

  10. Recent lake sedimentation in the middle and lower Yangtze basin inferred from 137Cs and 210Pb measurements

    NASA Astrophysics Data System (ADS)

    Xiang, L.; Lu, X. X.; Higgitt, D. L.; Wang, S. M.

    2002-11-01

    The reduction of water storage capacity in the lakes of the Yangtze basin was an important factor for the disastrous 1998 flooding. This study attempted to quantify sedimentation and its role in the water storage reduction in the middle and lower reaches of the Yangtze basin using the radionuclide of caesium-137 ( 137Cs) and lead-210 ( 210Pb) as tracers. Sixteen cores were taken from eight lakes, including the two largest lakes in the region (Poyanghu and Dongtinghu). The two dating techniques were used in combination to quantify recent sediment accumulation rates and their changes over the last few decades. The 137Cs and 210Pb measurements indicated higher sedimentation rates for Dongtinghu which were consistent with observed severe reduction of water storage capacity. The inferred sedimentation rates for the remaining lakes were lower and did not reflect the perceived rate of severe soil erosion upstream or the substantial water storage reduction. The low sedimentation rates inferred for most lakes tentatively suggest that sediment deposition was not the primary reason for the observed reduction in water storage capacity. Nevertheless, a clear increasing trend in sedimentation rates has been documented for most of the studied lakes over the past few decades. Sedimentation and its role in water storage reduction require further study due to the many problems associated with its quantification such as the post-depositional redistribution of sediments and water exchanges between the Yangtze river and the studied lakes.

  11. Selected elements and organic chemicals in bed sediment and fish tissue of the Tualatin River basin, Oregon, 1992-96

    USGS Publications Warehouse

    Bonn, Bernadine A.

    1999-01-01

    This report describes the results of a reconnaissance survey of elements and organic compounds found in bed sediment and fish tissue in streams of the Tualatin River Basin. The basin is in northwestern Oregon to the west of the Portland metropolitan area (fig. 1). The Tualatin River flows for about 80 miles, draining an area of about 712 square miles, before it enters the Willamette River. Land use in the basin changes from mostly forested in the headwaters, to mixed forest and agriculture, to predominately urban. The basin supports a growing population of more than 350,000 people, most of whom live in lower parts of the basin. Water quality in the Tualatin River and its tributaries is expected to be affected by the increasing urbanization of the basin.

  12. Chestnut Ridge Sediment Disposal Basin (D-025): Summary of closure under Rules Governing Hazardous Waste Management in Tennessee

    SciTech Connect

    Stone, J.E.

    1989-07-01

    On February 29, 1988, the Revised Closure Plan for Chestnut Ridge Sediment Disposal Basin,'' Y/TS-390 (Reference 1) was submitted to the United States Department of Energy (DOE) for review and transmittal to the Tennessee Department of Health and Environment (TDHE). The closure activities described in the closure plan have been performed. The purpose of this document is to summarize the closure activities for the Chestnut Ridge Sediment Disposal (CRSDB). The closure of CRSDB is a final closure. The Chestnut Ridge Sediment Disposal Basin (CRSDB), Unit D-025, was an unlined, man-made sediment disposal facility on Chestnut Ridge, south of New Hope Pond (NHP). The CRSDB was constructed during 1972--73 for the disposal of sediments hydraulically dredged from NHP. It was designed to hold approximately 30,000 cubic yards of sediments. Since 1973, the basin had been used for the periodic disposal of sediments excavated from NHP and its appurtenant structures. NHP has previously received discharges form RCRA-related waste streams. 19 refs., 3 figs., 1 tab.

  13. Biogeochemical Insights into B-Vitamins in the Coastal Marine Sediments of San Pedro Basin, CA

    NASA Astrophysics Data System (ADS)

    Monteverde, D.; Berelson, W.; Baronas, J. J.; Sanudo-Wilhelmy, S. A.

    2015-12-01

    Coastal marine sediments support a high abundance of mircoorganisms which play key roles in the cycling of nutrients, trace metals, and carbon, yet little is known about many of the cofactors essential for their growth, such as the B-vitamins. The suite of B-vitamins (B1, B2, B6, B7, B12) are essential across all domains of life for both primary and secondary metabolism. Therefore, studying sediment concentrations of B-vitamins can provide a biochemical link between microbial processes and sediment geochemistry. Here we present B-vitamin pore water concentrations from suboxic sediment cores collected in September 2014 from San Pedro Basin, a silled, low oxygen, ~900 m deep coastal basin in the California Borderlands. We compare the B-vitamin concentrations (measured via LCMS) to a set of geochemical profiles including dissolved Fe (65-160 μM), dissolved Mn (30-300 nM), TCO2, solid phase organic carbon, and δ13C. Our results show high concentrations (0.8-3nM) of biotin (B7), commonly used for CO2 fixation as a cofactor in carboxylase enzymes. Thiamin (B1) concentrations were elevated (20-700nM), consistent with previous pore water measurements showing sediments could be a source of B1 to the ocean. Cobalamin (B12), a cofactor required for methyl transfers in methanogens, was also detected in pore waters (~4-40pM). The flavins (riboflavin [B2] and flavin mononucleotide[FMN]), molecules utilized in external electron transfer, showed a distinct increase with depth (10-90nM). Interestingly, the flavin profiles showed an inverse trend to dissolved Fe (Fe decreases with depth) providing a potential link to culture experiments which have shown extracellular flavin release to be a common trait in some metal reducers. As some of the first B-vitamin measurements made in marine sediments, these results illustrate the complex interaction between the microbial community and surrounding geochemical environment and provide exciting avenues for future research.

  14. Basin formation and Neogene sedimentation in a backarc setting, Halmahera, eastern Indonesia

    SciTech Connect

    Hall, R. ); Nichols, G.J. )

    1991-03-01

    It has been proposed that basins in backarc setting form in association with subduction by thinning of continental crust, backarc spreading in oceanic crust, compression, or trapping of pieces of oceanic plate behind an arc. The Halmahera basin in eastern Indonesia developed in a backarc setting but does not fall into these categories; it formed by subsidence of thickened crust made up of imbricated Mesozoic-Paleogene arc and ophiolite rocks. Halmahera lies at the western edge of the Philippine Sea Plate in a complex zone of convergence between the Eurasian margin, the oceanic plates of the West Pacific, and the Australian/Indian Plate to the south. The basement is an imbricated complex of Mesozoic to Paleogene ophiolite, arc, and arc-related rocks. During the Miocene this basement complex formed an area of thickened crust upon which carbonate reef and reef-associated sediments were deposited. The authors interpret this shallow marine region to be similar to many of the oceanic plateaus and ridges found within the Philippine Sea Plate today. In the Late Miocene, convergence between the Philippine Sea Plate and the Eurasian margin resulted in the formation of the Halmahera Trench to the west of this region of thickened crust. Subduction of the Molucca Sea Plate caused the development of a volcanic island arc. Subsidence in the backarc area produced a broad sedimentary basin filled by clastics eroded from the arc and from uplifted basement and cover rocks. The basin was asymmetric with the thickest sedimentary fill on the western side, against the volcanic arc. The Halmahera basin was modified in the Plio-Pleistocene by east-west compression as the Molucca Sea Plate was eliminated by subduction.

  15. Diatom distribution as an environmental indicator in surface sediments of the West Philippine Basin

    NASA Astrophysics Data System (ADS)

    Shen, Linnan; Chen, Min; Lan, Binbin; Qi, Hongshuai; Zhang, Aimei; Lan, Dongzhao; Fang, Qi

    2016-05-01

    The distribution of diatoms from surface sediments of the West Philippine Basin was analyzed, with 68 species and varieties of diatoms from 26 genera identified. Diatom abundance varied spatially, with the absolute abundance of diatoms ranging from 0 to 3.4×104 frustules/g. The seven tropical pelagic diatoms were Alveus marinus, Azpeitia africana, Azpeitia nodulifera, Hemidiscus cuneiformis, Hemidiscus cuneiformis var. ventricosus, Roperia tesselata and Rhizosolenia bergonii. The relative abundance of these species was greater than 20%, and their distribution pattern in the sediments was overlaid by the flow of the Kuroshio Current. Ethmodiscus rex was present at 159 stations, formed the most abundant and dominant species in the diatomaceous ooze, and thus referred to as Ethmodiscus ooze. Ethmodiscus rex was also a major contributor to primary production in the region. A principal component analysis was employed to explain the relationship between samples and variations in diatom species from the WPB. Four diatom assemblages were distinguished, representing different oceanographic conditions; their spatial distributions were closely related with the North Equatorial Current and Kuroshio Current patterns in the region. These diatom assemblages can therefore be useful in deciphering late Quaternary palaeoceanographic reconstructions of the West Philippine Basin.

  16. Elemental chemistry of streambed sediments of the St. Croix River Basin, 2000

    USGS Publications Warehouse

    Brigham, Mark E.

    2002-01-01

    Streambed sediments from 30 sites in the St. Croix River Basin were analyzed for selected chemical elements. Possible occurrences of low-level contamination include: (1) elevated concentrations of arsenic, lead, silver, and to a lesser extent cadmium, copper, and mercury in the Namekagon River downstream of Hayward, Wisconsin; (2) elevated lead concentrations in the St. Croix River downstream of the Stillwater, Minnesota—Hudson, Wisconsin region; (3) slightly elevated concentrations of Arsenic, Cadmium, Copper, Lead, Mercury, Silver, Vanadium, and Zinc in the Kettle River downstream of Sandstone and Hinckley, Minnesota; (4) and substantially elevated mercury concentrations in Rush Creek downstream of Rush City, Minnesota. Elevated concentrations of copper, lead, and to a lesser extent cadmium, in Osceola Creek, downstream of Osceola, Wisconsin may be due to anthropogenic sources or contributions from bedrock that differs geochemically from sediments farther upstream. There does not appear to be large anthropogenic contributions of trace elements—above the background geochemical and atmospherically deposited levels—in the streams sampled for this study. Many of the elements appear to be associated with mineral sources. Concentrations of potentially toxic trace elements in the St. Croix River Basin generally were lower than concentrations associated with frequent adverse effects to aquatic biota. Exceptions were arsenic (7 of 30 samples) and mercury (1 of 30 samples).

  17. Hydrogen-isotopic variability in lipids from Santa Barbara Basin sediments

    NASA Astrophysics Data System (ADS)

    Li, Chao; Sessions, Alex L.; Kinnaman, Franklin S.; Valentine, David L.

    2009-08-01

    We conducted an extensive survey of hydrogen-isotopic compositions (D/H ratios) of diverse sedimentary lipids from the Santa Barbara Basin (SBB), offshore southern California. The main goal of this survey was to assess the diversity of D/H ratios in lipids from marine sediments, in order to provide a more detailed understanding of relevant biological and geochemical factors impacting lipid isotopic variability. A total of 1182 individual δD values are reported from two stations in SBB, one located in the suboxic basin depocenter and the other on the fully oxic flank of the basin. Sediments collected from the basin depocenter span a depth of ˜2.5 m and reach the methanogenic zone. Lipids that were analyzed include n-alkanes, n-alkanols and alkenols, short- and long-chain fatty acids, linear isoprenoids, steroids, and hopanoids, and exhibit several systematic patterns. First, there are no significant differences in δD values between the two sampling locations, nor with increasing depth for most lipids, indicating that degradation does not influence sedimentary lipid δD values. Second, relatively large differences in δD values among differing molecular structures are observed in all samples. n-Alkyl lipids of probable marine origin have typical δD values between -150 and -200‰, those from terrestrial leaf waxes and aquatic plants range from -80 to -170‰, while petroleum n-alkanes are typically -90 to -150‰. Third, lipids inferred to derive from bacteria (branched fatty acids and hopanols) living at the sediment surface or in the water column tend to be D-enriched relative to similar algal products by 30‰ or more. At the same time, several other lipids have δD values that decrease strongly with depth, presumably as a result of in situ production by anaerobic bacteria. This dichotomy in isotopic compositions of bacterial lipids is inconsistent with a nearly constant D/H fractionation during lipid biosynthesis, and likely reflects significant variations

  18. Global Overview On Delivery Of Sediment To The Coast From Tropical River Basins

    NASA Astrophysics Data System (ADS)

    Syvitski, J. P.; Kettner, A. J.; Brakenridge, G. R.

    2011-12-01

    Depending on definition, the tropics occupy between 16% and 19% of the earth's land surface, and discharge ~18.5% of the earth's fluvial water runoff. These flow regimes are driven by three types of sub-regional climate: rainforest, monsoon, and savannah. Even though the tropics include extreme precipitation events, particularly for the SE Asian islands, the general rainfall pattern alternates between wet and dry seasons as the ITCZ follows the sun and where annual monsoonal rain occurs. ITCZ convective rainfall is the dominant style of precipitation but this can be influenced by rare intra-tropical cyclone events, and by atmospheric river events set up by strong monsoonal conditions. Though a rainy season is normal (for example, portions of India discharge in summer may reach 50 times that of winter), the actual rainfall events are in the form of short bursts of precipitation (hours to days) separated by periods of dry (hours to weeks). Some areas of the tropics receive more than 100 thunderstorms per year. Rivers respond to this punctuated weather by seasonal flooding. For the smaller island nations and locales (e.g. Indonesia, Philippines, Borneo, Hainan, PNG, Madagascar, Hawaii, Taiwan) flash floods are common. Larger tropical river systems (Niger, Ganges, Brahmaputra, Congo, Amazon, Orinoco, Magdalena) show typical seasonally modulated discharges. The sediment flux from tropical rivers is approximately 17% to 19% of the global total - however individual river basins offer a wide range in sediment yields reflecting highly variable differences in their hinterland lithology, tectonic activity and volcanism, land-sliding, and relief. Human influences also greatly influence the range for tropical river sediment yield. Some SE Asian Rivers continue to be greatly affected by deforestation, road construction, and monoculture plantations. Sediment flux is more than twice the pre-Anthropocene flux in many of these SE Asian countries, especially where dams and reservoir

  19. Fungi in deep-sea sediments of the Central Indian Basin

    NASA Astrophysics Data System (ADS)

    Damare, Samir; Raghukumar, Chandralata; Raghukumar, S.

    2006-01-01

    Although a great amount of information is available on bacteria inhabiting deep-sea sediments, the occurrence of fungi in this environment has been poorly studied and documented. We report here the occurrence of fungi in deep-sea sediments from ˜5000 m depth in the Central Indian Basin (9-16°S and 73-76°E). A total of 181 cultures of fungi, most of which belong to terrestrial sporulating species, were isolated by a variety of isolation techniques. Species of Aspergillus and non-sporulating fungi were the most common. Several yeasts were also isolated. Maximum species diversity was observed in 0-2 cm sections of the sediment cores. Direct staining of the sediments with Calcofluor, a fluorescent optical brightener, revealed the presence of fungal hyphae in the sediments. Immunofluorescence using polyclonal antibodies raised against a deep-sea isolate of Aspergillus terreus (# A 4634) confirmed its presence in the form of hyphae in the sub-section from which it was isolated. A total of 25 representative species of fungi produced substantial biomass at 200 bar pressure at 30° as well as at 5 °C. Many fungi showed abnormal morphology at 200 bar/5 °C. A comparison of terrestrial isolates with several deep-sea isolates indicated that the former could grow at 200 bar pressure when growth was initiated with mycelial inocula. However, spores of a deep-sea isolate A. terreus (# A 4634), but not the terrestrial ones, showed germination at 200 bar pressure and 30 °C. Our results suggest that terrestrial species of fungi transported to the deep sea are initially stressed but may gradually adapt themselves for growth under these conditions.

  20. Interim report on streamflow, sediment discharge, and water quality in the Calabazas Creek Basin, Santa Clara County, California

    USGS Publications Warehouse

    Knott, J.M.; Pederson, G.L.; Middelburg, Robert F.

    1978-01-01

    Streamflow, sediment-discharge, and water-quality data are being collected in the Calabazas Creek basin, Santa Clara County, Calif., to determine annual water and sediment discharge at base-line conditions that are representative of a basin prior to urbanization. Results of the first 3 years of the study (1973-75) are given in this report. Climatic conditions during this period were representative of a very wet year (1973) and 2 years of above-average rainfall (1974 and 1975). Daily water and sediment discharge were monitored at three primary stations, and periodic measurements were made at five secondary stations during selected storms. Most of the total annual sediment discharge at each station was transported during a few days each year. Maximum daily sediment discharge in a given year ranged from 23 to 62 percent of the annual total. Daily water discharge at the gaging station Calabazas Creek at Rainbow Drive, near Cupertino, ranged from no flow to 3.31 cubic meters per second. Streamflow at this location was significantly augmented during low flow by diversion of water from the South Bay Aqueduct. Annual sediment discharge at Calabazas Creek at Rainbow Drive was 4,900 t in 1974 and 9,570 t in 1975. A large quantity of sediment was trapped in a debris basin at Comer Drive upstream from this station during both years. If this sediment had not been trapped, sediment discharge at the station would have been about 35 percent greater in 1974 and 30 percent greater in 1975. Most of the trapped sediment consists of sand and gravel that would probably have been deposited in the Calabazas Creek channel downstream from the station. (Woodard-USGS)

  1. Uncertainty in flow and sediment projections due to future climate scenarios for the 3S Rivers in the Mekong Basin

    NASA Astrophysics Data System (ADS)

    Shrestha, Bikesh; Cochrane, Thomas A.; Caruso, Brian S.; Arias, Mauricio E.; Piman, Thanapon

    2016-09-01

    Reliable projections of discharge and sediment are essential for future water and sediment management plans under climate change, but these are subject to numerous uncertainties. This study assessed the uncertainty in flow and sediment projections using the Soil and Water Assessment Tool (SWAT) associated with three Global Climate Models (GCMs), three Representative Concentration Pathways (RCPs) and three model parameter (MP) sets for the 3S Rivers in the Mekong River Basin. The uncertainty was analyzed for the short term future (2021-2040 or 2030s) and long term future (2051-2070 or 2060s) time horizons. Results show that dominant sources of uncertainty in flow and sediment constituents vary spatially across the 3S basin. For peak flow, peak sediment, and wet seasonal flows projection, the greatest uncertainty sources also vary with time horizon. For 95% low flows and for seasonal and annual flow projections, GCM and MP were the major sources of uncertainty, whereas RCPs had less of an effect. The uncertainty due to RCPs is large for annual sediment load projections. While model parameterization is the major source of uncertainty in the short term (2030s), GCMs and RCPs are the major contributors to uncertainty in flow and sediment projections in the longer term (2060s). Overall, the uncertainty in sediment load projections is larger than the uncertainty in flow projections. In general, our results suggest the need to investigate the major contributing sources of uncertainty in large basins temporally and at different scales, as this can have major consequences for water and sediment management decisions. Further, since model parameterization uncertainty can play a significant role for flow and sediment projections, there is a need to incorporate hydrological model parameter uncertainty in climate change studies and efforts to reduce the parameter uncertainty as much as possible should be considered through a careful calibration and validation process.

  2. The isotopic composition of authigenic chromium in anoxic marine sediments: A case study from the Cariaco Basin

    NASA Astrophysics Data System (ADS)

    Reinhard, Christopher T.; Planavsky, Noah J.; Wang, Xiangli; Fischer, Woodward W.; Johnson, Thomas M.; Lyons, Timothy W.

    2014-12-01

    Chromium (Cr) isotopes are an emerging proxy for tracking redox processes at the Earth's surface. However, there has been limited exploration of the Cr isotope record of modern and recent marine sediments. The basic inorganic chemistry of Cr suggests that anoxic marine basins should factor prominently in the global Cr cycle and that sediments deposited within anoxic basins may offer a valuable Cr isotope archive throughout Earth's history. Here, we present δ53Cr data from sediments of the Cariaco Basin, Venezuela-a 'type' environment for large, perennially anoxic basins with a relatively strong hydrological connection to the global oceans. We document a marked positive shift in bulk δ53Cr values following the termination of the Last Glacial Maximum, followed by relative stasis. Based on a suite of independent redox proxies, this transition marks a switch from oxic to persistently anoxic and sulfidic (euxinic) depositional conditions within the basin. We find good agreement between two independent approaches toward estimating the δ53Cr composition of authigenic Cr in euxinic Cariaco Basin sediments and that these estimates are very similar to the δ53Cr composition of modern open Atlantic Ocean seawater. These data, together with considerations of reaction kinetics and mass balance within the Cariaco Basin, are consistent with the hypothesis that anoxic marine settings can serve as a chemical archive of first-order trends in seawater δ53Cr composition. Additionally, the Cariaco Basin data suggest that there has been secular stability in the average δ53Cr value of Atlantic seawater over the last ∼15 kyr.

  3. Pre- to syncollisional sedimentation in the Middle Jurassic to Cretaceous Methow-Tyaughton Basin, northern Washington, southwestern British Columbia

    SciTech Connect

    Garver, J.I. ); Umhoefer, P.J. ); McGroder, M.F. ); Bourgeois, J. )

    1990-05-01

    Palinspastic reconstruction of Cretaceous to Tertiary dextral-slip faults restores the Methow-Tyaughton basin to a 300+ km-long basin that contains Middle Jurassic to middle Cretaceous strata. Sedimentary rocks and structures within the basin record a transition from sedimentation on the western margin of the intermontane terrane to sedimentation within an actively deforming collision zone along the Intermontane and Insular terrane boundary in the middle Cretaceous. Following Middle Jurassic terrane amalgamation, the Methow-Tyaughton was a short-lived fore-arc basin in the Callovian. Oxfordian-Valanginian sedimentation was marked by low depositional rates of volcanic and plutonic debris, probably along a transform-rift margin. Hauterivian-Aptian sedimentary rocks are generally fine-grained turbidite packages with minor interbedded tuffs, and volcanic rocks are interbedded at the western basin margin. Hauterivian rocks reflect a change to a back-arc basin setting. Albian contraction within the basement Bridge River and Cadwallader terranes resulted in an intrabasinal uplift that supplied chert-rich detritus to two flanking subbasins. At the same time, west-derived, volcanic detritus shed off the volcanic cover to the Insular terrane, and east-derived arkosic sediment shed off the Omineca Crystalline belt. Tectonic subsidence and basin infilling occurred from about 110 to 95 Ma, capped by a thick sequence of nonmarine clastic rocks and andesites. Intrabasin deformation occurred from about 100 to 85 ma. After the termination of andesitic volcanism and contractional deformation the basin was cut by dextral-slip faults (post 85 Ma) that likely were driven by oblique Kula-North America interaction.

  4. Reconnaissance assessment of erosion and sedimentation in the Canada de los Alamos Basin, Los Angeles and Ventura counties, California

    USGS Publications Warehouse

    Knott, J.M.

    1978-01-01

    An assessment of present erosion and sedimentation conditions in the Canada de Los Alamos basin, Calif., was made to aid in estimating the impact of off-road-vehicle use on the sediment yield of the basin. Evaluations were made by reconnaissance techniques and by comparing the study area with other off-road-vehicle sites in California. Major-storm sediment yields for the basin were estimated, using empirical equations developed for the Transverse Ranges and measurements of gully erosion in a representative off-road vehicle basin. Normal major-storm yields of 73,200 cubic yards would have to be increased to about 98,000 cubic yards to account for the existing level of accelerated erosion caused by off-road vehicles. Long-term sediment yield of the Canada de Los Alamos basin upstream from its confluence with Gorman Creek, under present conditions of off-road-vehicle use, is approximately 420 cubic yards per square mile per year--a rate that is considerably lower than a previous estimate of 1,270 cubic yards per square mile per year for the total catchment area above Pyramid Lake. (Woodard-USGS)

  5. Reconnaissance assessment of erosion and sedimentation in the Canada de los Alamos basin, Los Angeles and Ventura Counties, California

    USGS Publications Warehouse

    Knott, J.M.

    1980-01-01

    An assessment of present erosion and sedimentation conditions in the Ca?ada de los Alamos basin was made to aid in estimating the impact of off-road-vehicle use on the sediment yield of the basin. Impacts of off-road vehicles were evaluated by reconnaissance techniques and by comparing the study area with other offroad-vehicle sites in California. Major-storm sediment yields for the basin were estimated using empirical equations developed for the Transverse Ranges and measurements of gully erosion in a representative off-road-vehicle basin. Normal major-storm yields of 73,200 cubic yards would have to be increased to about 98,000 cubic yards to account for the existing level of accelerated erosion caused by off-road vehicles. Long-term sediment yield of the Ca?ada de los Alamos basin upstream from its confluence with Gorman Creek, under present conditions of off-road-vehicle use, is approximately 420 cubic yards per square mile per year--a rate that is considerably lower than a previous estimate of 1,270 cubic yards per square mile per year for the total catchment area above Pyramid Lake.

  6. Landscape response to late Pleistocene climate change in NW Argentina: Sediment flux modulated by basin geometry and connectivity

    NASA Astrophysics Data System (ADS)

    Schildgen, Taylor F.; Robinson, Ruth A. J.; Savi, Sara; Phillips, William M.; Spencer, Joel Q. G.; Bookhagen, Bodo; Scherler, Dirk; Tofelde, Stefanie; Alonso, Ricardo N.; Kubik, Peter W.; Binnie, Steven A.; Strecker, Manfred R.

    2016-02-01

    Fluvial fill terraces preserve sedimentary archives of landscape responses to climate change, typically over millennial timescales. In the Humahuaca Basin of NW Argentina (Eastern Cordillera, southern Central Andes), our 29 new optically stimulated luminescence ages of late Pleistocene fill terrace sediments demonstrate that the timing of past river aggradation occurred over different intervals on the western and eastern sides of the valley, despite their similar bedrock lithology, mean slopes, and precipitation. In the west, aggradation coincided with periods of increasing precipitation, while in the east, aggradation coincided with decreasing precipitation or more variable conditions. Erosion rates and grain size dependencies in our cosmogenic 10Be analyses of modern and fill terrace sediments reveal an increased importance of landsliding compared to today on the west side during aggradation, but of similar importance during aggradation on the east side. Differences in the timing of aggradation and the 10Be data likely result from differences in valley geometry, which causes sediment to be temporarily stored in perched basins on the east side. It appears as if periods of increasing precipitation triggered landslides throughout the region, which induced aggradation in the west, but blockage of the narrow bedrock gorges downstream from the perched basins in the east. As such, basin geometry and fluvial connectivity appear to strongly influence the timing of sediment movement through the system. For larger basins that integrate subbasins with differing geometries or degrees of connectivity (like Humahuaca), sedimentary responses to climate forcing are likely attenuated.

  7. Hypoxic cyclicity in sediments of Soledad Basin, Baja Mexico: A record of high-frequency climate fluctuations?

    NASA Astrophysics Data System (ADS)

    Westman, A. E.; Brooks, G. R.; Lea, C.

    2007-05-01

    The sedimentary record in Soledad Basin, 45 km west of Baja, Mexico, shows high-frequency oscillations in hypoxia, which can be linked to fluctuations in climate. Soledad Basin, a semi-enclosed basin with a sill depth of 290m, has been shown to exhibit variable levels of hypoxia throughout the geologic past. Located at the intersection of the California Current and California Undercurrent, Soledad Basin is highly responsive to changes in current strength and upwelling, the combination of which creates fluctuations in hypoxia. During climatic cool periods, the California Current is weakened decreasing upwelling and biologic productivity along the Baja Borderland. This causes increased hypoxia in Soledad Basin. The California Undercurrent is also weakened during these cooler periods and brings less nutrients and oxygen to the basin further increasing hypoxia. Since Soledad Basin sediments are undisturbed and have accumulated rapidly, this is a prime location to study high frequency variations in hypoxia in the sedimentary record. The objective of this study was to examine how and to what extent hypoxic events have been recorded in the sedimentary record of Soledad Basin, and gain insight into what controls these events. Surface sediment samples and a single 1.1m gravity core were collected aboard the S.S.V. Robert C. Seamans on a SEA Semester cruise in October 2005. The core was taken at a depth of 490 m near the deepest point of the basin. The core contained laminated sediments consisting of >95% mud. Using 210Pb analysis, a sedimentation rate of 15 cm over the past 100 years was determined, which is consistent with previous research. Trace metal analyses were performed at the cm-scale on selected intervals between 0.34-0.44m and 0.78-0.92m. These intervals correspond to dark organic-rich (>15% organic content) laminations alternating with lighter layers containing less organic material (<15% organic content). All sediments were found to be enriched in Molybdenum

  8. Structure and sediment budget of Yinggehai-Song Hong basin, South China Sea: Implications for Cenozoic tectonics and river basin reorganization in Southeast Asia

    NASA Astrophysics Data System (ADS)

    Lei, Chao; Ren, Jianye; Sternai, Pietro; Fox, Matthew; Willett, Sean; Xie, Xinong; Clift, Peter D.; Liao, Jihua; Wang, Zhengfeng

    2015-08-01

    The temporal link between offshore stratigraphy and onshore topography is of key importance for understanding the long-term surface evolution of continental margins. Here we present a grid of regional, high-quality reflection seismic and well data to characterize the basin structure. We identify fast subsidence of the basin basement and a lack of brittle faulting of the offshore Red River fault in the Yinggehai-Song Hong basin since 5.5 Ma, despite dextral strike-slip movement on the onshore Red River fault. We calculate the upper-crustal, whole-crustal, and whole-lithospheric stretching factors for the Yinggehai-Song Hong basin, which show that the overall extension observed in the upper crust is substantially less than that observed for the whole crust or whole lithosphere. We suggest that fast basement subsidence after 5.5 Ma may arise from crustal to lithospheric stretching by the regional dynamic lower crustal/mantle flow originated by collision between India-Eurasia and Indian oceanic subduction below the Eurasian margin. In addition, we present a basin wide sediment budget in the Yinggehai-Song Hong basin to reconstruct the sedimentary flux from the Red River drainage constrained by high-resolution age and seismic stratigraphic data. The sediment accumulation rates show a sharp increase at 5.5 Ma, which suggests enhanced onshore erosion rates despite a slowing of tectonic processes. This high sediment supply filled the accommodation space produced by the fast subsidence since 5.5 Ma. Our data further highlight two prominent sharp decreases of the sediment accumulation at 23.3 Ma and 12.5 Ma, which could reflect a loss of drainage area following headwater capture from the Paleo-Red River. However, the low accumulation rate at 12.5 Ma also correlates with drier and therefore less erosive climatic conditions.

  9. Quaternary transpression and lacustrine sedimentation in the San Lorenzo area (Sant'Arcangelo Basin, Italy)

    NASA Astrophysics Data System (ADS)

    Onofrio, Vincenzo; Tropeano, Marcello; Festa, Vincenzo; Moretti, Massimo; Sabato, Luisa

    2009-12-01

    Quaternary lacustrine sedimentation of the San Lorenzo Succession represents one of the more recent steps in the evolution of the northern part of the Sant'Arcangelo Basin. The latter is a large Pliocene to Pleistocene wedge-top depozone of the southern Apennines foreland-basin system that developed close to the front of the thrust belt in southern Italy. The lower to middle Pleistocene lacustrine deposits are composed of siltstone and claystone interbedded with sandstone, carbonate and volcaniclastic beds, arranged in fining-upward sequences. The overall stratigraphical, sedimentological, and structural data collected demonstrate that the San Lorenzo lacustrine deposits formed when the northern sector of the Sant'Arcangelo Basin was undergoing tectonic deformation. In particular, new data reveal the presence of strike-slip syndepositional faults. These faults belong to positive flower-type structures, which developed in a left-lateral transpressive tectonic regime characterized by a E-W horizontal component of shear stress. The lacustrine deposits recorded the activity of these faults showing growth structures represented mainly by gentle synclines, as well as other minor folds. The tectonic activity of the main faults formed an endorheic area with at least two different depocentres accumulating lacustrine successions.

  10. Sequence stratigraphic features of nonmarine Cretaceous sediments in Songliao basin, northeast China

    SciTech Connect

    Huaida Hsu )

    1991-03-01

    Abundant fossils indicate that Cretaceous siliciclastics of the Songliao basin were deposited in nonmarine environments. However, a relative lake-level curve constructed by the author is somewhat like the eustatic sea-level curve for this period published by Haq et al., 1987. Based on stratigraphic work, a revised definition of a supersequence is proposed. The composition of the lowstand system tract in the nonmarine sequence is different from its marine counterpart, such as the lowstand-prograding complex being absent in some sequences and the basin floor fan often replaced by the alluvial fan or evaporate. A sequence that juts across the reflection event, signified T{sub 2}, which separates the Aptian (Quantou Formation) and Albian (Qingshankou Formation) units, has been studied in detail. Numerous small symmetrical stair-like grabens, containing erosional and leveed channels, developed on top of the Quantou Formation. A number of oil reservoirs are related to channel sands, overbank sediments, and turbidite lobes that form a complex network over a large area east of the Daqing oil field. No shelf edge is present in the nonmarine facies tract, and the transgressive system tract is only developed on the western flank of the basin. Cores, well logs, high-resolution and three-dimensional seismic data, and seismic modeling have been studied from this area.

  11. Trace elements in lake sediment, macrozoobenthos, and fish near a coal ash disposal basin

    USGS Publications Warehouse

    Hatcher, Charles O.; Ogawa, Roann E.; Poe, Thomas P.; French, John R. P.

    1992-01-01

    Of the 29 trace elements examined, arsenic and cobalt were significantly (p <0.05) more concentrated in sediment nearest the coal ash basin except in spring, when little or no difference was detected. Arsenic and bromine were significantly higher in oligochaetes, and selenium was significantly higher in both oligochaetes and chironomids taken from proximal stations than in those taken from reference stations. Selenium, bromine, cobalt, nickel, and chromium were higher in young-of-the-year brown bullheads taken nearer the disposal basin in fall 1983. Selenium was higher in adult spottail shiners taken at the proximal station in spring 1984, and bromine was higher in yearling white bass from the proximal station in fall 1983 and 1984. None of the trace elements was higher in adult yellow perch or adult brown bullheads at any time. Fewer spottail shiners and yearling white bass were caught close to the disposal basin than far away, which may indicate avoidance by these fish of increased concentrations of trace elements contained within the ash effluent.

  12. Early Eocene tectonics and sedimentation in Northern Fossil basin, Wyoming Overthrust Belt

    SciTech Connect

    Hurst, D.J.; Steidtmann, J.R.

    1984-07-01

    The Tunp Member of the early Eocene Wasatch Formation in southwestern Wyoming was shed from rising thrust sheets as debris flows containing abundant, very poorly sorted to unsorted, coarse clastic material in a mudstone matrix. Deposition occurred on the margins of the northern Fossil basin as coalesced alluvial fans and fan deltas. Small braided streams traversed the surface of these fans and reworked debris flow material, but the resultant fluvial deposits are volumetrically minor. Tunp Member deposits are preserved in three north-south-trending belts around the periphery of the northern Fossil basin. Each belt had a separate source in discrete highlands created by early Eocene motion on the Absaroka, Tunp, and Crawford thrust faults. These thrusts possessed unique characteristics of uplift style, provenance, and duration of in-situ weathering that are reflected by differences in clast lithology, size and rounding, as well as thickness and areal extent of the deposits resulting from each thrust. The results of this study have several important implications about thrust belt development: (1) passive rotation of older thrusts by younger ones can provide an uplifted source for syntectonic sediments, (2) the tenet that major thrusts young in the direction of tectonic transport may be violated by the Tunp and Crawford thrusts in the Fossil basin area, and (3) those heretical faults (i.e., Tunp and Crawford) possess a similar geometry that is distinct from other thrust faults in the area.

  13. Biosphere frontiers of subsurface life in the sedimented hydrothermal system of Guaymas Basin

    PubMed Central

    Teske, Andreas; Callaghan, Amy V.; LaRowe, Douglas E.

    2014-01-01

    Temperature is one of the key constraints on the spatial extent, physiological and phylogenetic diversity, and biogeochemical function of subsurface life. A model system to explore these interrelationships should offer a suitable range of geochemical regimes, carbon substrates and temperature gradients under which microbial life can generate energy and sustain itself. In this theory and hypothesis article, we make the case for the hydrothermally heated sediments of Guaymas Basin in the Gulf of California as a suitable model system where extensive temperature and geochemical gradients create distinct niches for active microbial populations in the hydrothermally influenced sedimentary subsurface that in turn intercept and process hydrothermally generated carbon sources. We synthesize the evidence for high-temperature microbial methane cycling and sulfate reduction at Guaymas Basin – with an eye on sulfate-dependent oxidation of abundant alkanes – and demonstrate the energetic feasibility of these latter types of deep subsurface life in previously drilled Guaymas Basin locations of Deep-Sea Drilling Project 64. PMID:25132832

  14. Land-use effects on erosion, sediment yields, and reservoir sedimentation: a case study in the Lago Loiza Basin, Puerto Rico

    USGS Publications Warehouse

    Gellis, A.C.; Webb, R.M.T.; McIntyre, S.C.; Wolfe, W.J.

    2006-01-01

     Lago Loíza impounded in 1953 to supply San Juan, Puerto Rico, with drinking water; by 1994, it had lost 47% of its capacity. To characterize sedimentation in Lago Loíza, a study combining land-use history, hillslope erosion rates, and subbasin sediment yields was conducted. Sedimentation rates during the early part of the reservoir’s operation (1953– 1963) were slightly higher than the rates during 1964–1990. In the early history of the reservoir, cropland comprised 48% of the basin and erosion rates were high. Following economic shifts during the 1960s, cropland was abandoned and replaced by forest, which increased from 7.6% in 1950 to 20.6% in 1987. These land-use changes follow a pattern similar to the northeastern United States. Population in the Lago Loíza Basin increased 77% from 1950 to 1990, and housing units increased 194%. Sheetwash erosion measured from 1991 to 1993 showed construction sites had the highest sediment concentration (61,400 ppm), followed by cropland (47,400 ppm), pasture (3510 ppm), and forest (2050 ppm). This study illustrates how a variety of tools and approaches can be used to understand the complex interaction between land use, upland erosion, fluvial sediment transport and storage, and reservoir sedimentation

  15. Shelf-to-basin iron shuttling enhances vivianite formation in deep Baltic Sea sediments

    NASA Astrophysics Data System (ADS)

    Reed, Daniel C.; Gustafsson, Bo G.; Slomp, Caroline P.

    2016-01-01

    Coastal hypoxia is a growing and persistent problem largely attributable to enhanced terrestrial nutrient (i.e., nitrogen and phosphorus) loading. Recent studies suggest phosphorus removal through burial of iron (II) phosphates, putatively vivianite, plays an important role in nutrient cycling in the Baltic Sea - the world's largest anthropogenic dead zone - yet the dynamics of iron (II) phosphate formation are poorly constrained. To address this, a reactive-transport model was used to reconstruct the diagenetic and depositional history of sediments in the Fårö basin, a deep anoxic and sulphidic region of the Baltic Sea where iron (II) phosphates have been observed. Simulations demonstrate that transport of iron from shelf sediments to deep basins enhances vivianite formation while sulphide concentrations are low, but that pyrite forms preferentially over vivianite when sulphate reduction intensifies due to elevated organic loading. Episodic reoxygenation events, associated with major inflows of oxic waters, encourage the retention of iron oxyhydroxides and iron-bound phosphorus in sediments, increasing vivianite precipitation as a result. Results suggest that artificial reoxygenation of the Baltic Sea bottom waters could sequester up to 3% of the annual external phosphorus loads as iron (II) phosphates, but this is negligible when compared to potential internal phosphorus loads due to dissolution of iron oxyhydroxides when low oxygen conditions prevail. Thus, enhancing vivianite formation through artificial reoxygenation of deep waters is not a viable engineering solution to eutrophication in the Baltic Sea. Finally, simulations suggest that regions with limited sulphate reduction and hypoxic intervals, such as eutrophic estuaries, could act as important phosphorus sinks by sequestering vivianite. This could potentially alleviate eutrophication in shelf and slope environments.

  16. Polycyclic aromatic hydrocarbons in water, sediment and soil of the Songhua River Basin, China.

    PubMed

    Ma, Wan-Li; Liu, Li-Yan; Qi, Hong; Zhang, Zi-Feng; Song, Wei-Wei; Shen, Ji-Min; Chen, Zhong-Lin; Ren, Nan-Qi; Grabuski, Josey; Li, Yi-Fan

    2013-10-01

    The Songhua River is the third largest river in China and the primary source of drinking and irrigation water for northeastern China. The distribution of 16 priority polycyclic aromatic hydrocarbons (PAHs) in water [dissolved water (DW) and suspended particulate matter (SPM)], sediment, and soil in the river basin was investigated, and the associated risk of cancer from these PAHs was also assessed. The total concentration of PAHs ranged from 13.9 to 161 ng L(-1) in DW, 9.21 to 83.1 ng L(-1) in SPM, 20.5 to 632 ng g(-1) dw (dry weight) in sediment, and from 30.1 to 870 ng g(-1) dw in soil. The compositional pattern of PAHs indicated that three-ring PAHs were predominant in DW and SPM samples, while four-ring PAHs dominated in sediment and soil samples. The spatial distribution of PAHs revealed some site-specific sources along the river, with principal component analysis indicating that these were from pyrogenic sources (such as coal and biomass combustion, and vehicle emissions) and coke oven emission distinguished as the main source of PAHs in the Songhua River Basin. Based on the ingestion of PAH-contaminated drinking water from the Songhua River, cancer risk was quantitatively estimated by combining the Incremental Lifetime Cancer Risk assessment model and BaP-equivalent concentration for five age groups of people (adults, teenagers, children, toddlers, and infants). Overall, the results suggest that the estimated integrated lifetime cancer risk for all groups was in acceptable levels. This study is the first attempt to provide information on the cancer risk of PAHs in drinking water from the Songhua River.

  17. Benthic foraminifera records in marine sediments during the Holocene from Pescadero basin, Gulf of California, Mexico

    NASA Astrophysics Data System (ADS)

    Valdez, M.; Perez-Cruz, L. L.; Roy, P.; Monreal, M.; Fenero, R.

    2013-05-01

    Gravity core T-56 (256 cm length) was collected in Pescadero Basin located on the western side of the Gulf of California within the oxygen minim zone (OMZ) at 597 cm depth, aboard of the R/V "El Puma". Pescadero basin is located at mouth of the gulf; because of its location is sensitive to record the changes in the gulf and in the Eastern Pacific Ocean. The sedimentary sequence is analyzed to contribute to the understanding the oceanographic variability in the southern part of the gulf of California during the Holocene using benthic foraminifera assemblages and organic carbon as proxies of organic matter flux and bottom water oxygenation. In general, the core is characterized by silty-clay sediments, and it exhibits a turbidite between 198 and 134 cm, distinguished by sandy sediments and reworking material. From 134 cm to the top shows a visible laminated structure. The initial chronology is based on three AMS radiocarbon dates, and estimated sedimentation rates are 0.22 and 0.19 mm/yr for the first 32 cm of the core. Six radiocarbon dates are in progress. Preliminary results of benthic foraminiferal assemblages showed that species of Bolivina are dominated, mainly megalospheric forms, from 134 cm to top of the core. They are small and thin-shelled forms (e.g., Bolivina subadvena, Bolivina minuta, Bolivina seminuda, Bolivina plicata), and also Buliminella, Cassidulina and Epistominella are abundant. In particular, species of Bolivina are environmental indicators and exhibit a typical reproductive dimorphism. The predominance of the genus Bolivina suggest organic flux variations, because of the productivity changes that might be related to changes in ocean circulation and in the environmental variability in the region.

  18. Radiolarian polycystine in holocenic sediments from Carmen Basin, Gulf of California—their paleoenvironment significant

    NASA Astrophysics Data System (ADS)

    Monzon, O.; Perez-Cruz, L. L.; Barbara, L.; Schmidt, S.

    2013-05-01

    In this study radiolarian assemblages are analyzed in a sedimentary sequence from Carmen Basin in order to reconstruct the paleoenvironment conditions in the study area during the past 200 (?) years. The sequence sediment (core C53) was collected using a box core in western sector of Carmen Basin, at 560 m depth, aboard the R/V El Puma. The core C53 it has 34 cm length and is characterized by silty-clays sediments and fine laminated structure throughout the core.The age model is based on 210Pb and radiocarbon AMS methods (now in progress). According with the 210Pb the sedimentation rate in the first 15 cm of the core is ca. 1.75 mm/yr. Radiolarians are counted and identified in 114 continuous samples along the core. Radiolarians are used as proxies of temperature, nutrients and ocean circulation. Here preliminary results are presented. Two hundred and ten taxa were identified in all samples, belong to Spumellaria and Nassellaria orders, 90 and 120 taxa, respectively. Twenty seven were dominant (e. g. Druppatractus variabilis, Larcopyle buetschlii, Phorticium pylonium, Tetrapyle octacantha, Arachnocorallium calvata, Clathrocircus stapedius, Cladoscenuim ancoratum, Lithomelissa pentacantha, Lithomelissa setosa, Pseudocubus obeliscus and Pseudodyctiophimus gracilipes). They are in more than 1% in average in all samples. The stratigraphy distribution of the dominant species throughout the core suggests two general environments. 1) High productivity conditions from 34.5 to 16 cm, based on the abundance of Lithomelissa pentacantha and L. setosa (surface dwelling taxa associated by upwelling processes), and 2) Less productivity and stratified conditions from16 cm to top, were Tetrapyle octacantha group and Phorticium pylonium group are dominant.

  19. Development of a time-stepping sediment budget model for assessing land use impacts in large river basins.

    PubMed

    Wilkinson, S N; Dougall, C; Kinsey-Henderson, A E; Searle, R D; Ellis, R J; Bartley, R

    2014-01-15

    The use of river basin modelling to guide mitigation of non-point source pollution of wetlands, estuaries and coastal waters has become widespread. To assess and simulate the impacts of alternate land use or climate scenarios on river washload requires modelling techniques that represent sediment sources and transport at the time scales of system response. Building on the mean-annual SedNet model, we propose a new D-SedNet model which constructs daily budgets of fine sediment sources, transport and deposition for each link in a river network. Erosion rates (hillslope, gully and streambank erosion) and fine sediment sinks (floodplains and reservoirs) are disaggregated from mean annual rates based on daily rainfall and runoff. The model is evaluated in the Burdekin basin in tropical Australia, where policy targets have been set for reducing sediment and nutrient loads to the Great Barrier Reef (GBR) lagoon from grazing and cropping land. D-SedNet predicted annual loads with similar performance to that of a sediment rating curve calibrated to monitored suspended sediment concentrations. Relative to a 22-year reference load time series at the basin outlet derived from a dynamic general additive model based on monitoring data, D-SedNet had a median absolute error of 68% compared with 112% for the rating curve. RMS error was slightly higher for D-SedNet than for the rating curve due to large relative errors on small loads in several drought years. This accuracy is similar to existing agricultural system models used in arable or humid environments. Predicted river loads were sensitive to ground vegetation cover. We conclude that the river network sediment budget model provides some capacity for predicting load time-series independent of monitoring data in ungauged basins, and for evaluating the impact of land management on river sediment load time-series, which is challenging across large regions in data-poor environments. PMID:23968738

  20. Development of a time-stepping sediment budget model for assessing land use impacts in large river basins.

    PubMed

    Wilkinson, S N; Dougall, C; Kinsey-Henderson, A E; Searle, R D; Ellis, R J; Bartley, R

    2014-01-15

    The use of river basin modelling to guide mitigation of non-point source pollution of wetlands, estuaries and coastal waters has become widespread. To assess and simulate the impacts of alternate land use or climate scenarios on river washload requires modelling techniques that represent sediment sources and transport at the time scales of system response. Building on the mean-annual SedNet model, we propose a new D-SedNet model which constructs daily budgets of fine sediment sources, transport and deposition for each link in a river network. Erosion rates (hillslope, gully and streambank erosion) and fine sediment sinks (floodplains and reservoirs) are disaggregated from mean annual rates based on daily rainfall and runoff. The model is evaluated in the Burdekin basin in tropical Australia, where policy targets have been set for reducing sediment and nutrient loads to the Great Barrier Reef (GBR) lagoon from grazing and cropping land. D-SedNet predicted annual loads with similar performance to that of a sediment rating curve calibrated to monitored suspended sediment concentrations. Relative to a 22-year reference load time series at the basin outlet derived from a dynamic general additive model based on monitoring data, D-SedNet had a median absolute error of 68% compared with 112% for the rating curve. RMS error was slightly higher for D-SedNet than for the rating curve due to large relative errors on small loads in several drought years. This accuracy is similar to existing agricultural system models used in arable or humid environments. Predicted river loads were sensitive to ground vegetation cover. We conclude that the river network sediment budget model provides some capacity for predicting load time-series independent of monitoring data in ungauged basins, and for evaluating the impact of land management on river sediment load time-series, which is challenging across large regions in data-poor environments.

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

    PubMed

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

    2007-04-01

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

  2. Sediment storage quantification and postglacial evolution of an inner-alpine sedimentary basin (Gradenmoos, Schober Mountains, Austria)

    NASA Astrophysics Data System (ADS)

    Götz, J.; Buckel, J.; Otto, J. C.; Schrott, L.

    2012-04-01

    Knickpoints in longitudinal valley profiles of alpine headwater catchments can be frequently assigned to the lithological and tectonical setting, to damming effects through large (rockfall) deposits, or to the impact of Pleistocene glaciations causing overdeepened basins. As a consequence various sedimentary sinks developed, which frequently interrupt sediment flux in alpine drainage basins. Today these locations may represent landscape archives documenting a sedimentary history of great value for the understanding of alpine landscape evolution. The glacially overdeepened Gradenmoos basin at 1920 m a.s.l. (an alpine lake mire with adjacent floodplain deposits and surrounding slope storage landforms; approx. 4.1 km2) is the most pronounced sink in the studied Gradenbach catchment (32.5 km2). The basin is completely filled up with sediments delivered by mainly fluvial processes, debris flows, and rock falls, it is assumed to be deglaciated since Egesen times and it is expected to archive a continuous stratigraphy of postglacial sedimentation. As the analysis of denudation-accumulation-systems is generally based on back-calculation of stored sediment volumes to a specific sediment delivering area, most reliable results will be consequently obtained (1) if sediment output of the system can be neglected for the investigated period of time, (2) if - due to spatial scale - sediment storage can be assessed quantitatively with a high level of accuracy, and (3) if the sediment contributing area can be clearly delimited. All three aspects are considered to be fulfilled to a high degree within the Gradenmoos basin. Sediment storage is quantified using geophysical methods, core drillings and GIS modelling whereas postglacial reconstruction is based on radiocarbon dating and palynological analyses. Subject to variable subsurface conditions, different geophysical methods were applied to detect bedrock depth. Electrical resistivity surveying (2D/3D) was used most extensively as it

  3. Evidence For Diffusion Dominant Solute Transport In The Ordovician Sediments Of The Michigan Basin

    NASA Astrophysics Data System (ADS)

    Sykes, J. F.; Normani, S. D.; Yin, Y.

    2011-12-01

    A Deep Geologic Repository (DGR) for Low and Intermediate Level Radioactive Waste has been proposed by Ontario Power Generation for the Bruce site near Tiverton, Ontario, 225 km northwest of Toronto. The DGR concept envisions a repository excavated at a depth of 680 m within the low permeability (less than 10e-14 m/s) limestone Cobourg Formation beneath 200 m of Ordovician age shale. The attributes of the hydrogeologic environment for the DGR, and the potential for solute transport from a repository, were assessed using numerical models for hypothesis testing and numerical experiments. Data for the analyses included Westbay pressure measurements from the DGR site investigation boreholes. These data indicate that the Cambrian sandstone and the Niagaran Group in the Silurian are over-pressured relative to density corrected hydrostatic levels while the Ordovician limestone and shale are significantly under-pressured. The abnormal pressures provide evidence that solute transport in the low permeable Ordovician sediments is diffusion dominant. Sedimentary basins, when at hydrological equilibrium, normally show a near-hydrostatic pressure distribution. Under certain conditions, some excess pressure or pressure greater than hydrostatic can develop in low-permeability layers or other hydraulically isolated parts of systems. The processes commonly invoked to explain these over-pressures are compaction, hydrocarbon migration, diagenesis, tectonic stress or more simply topographic effects. Explanations of abnormal under-pressures include osmosis, exhumation, glaciation unloading, crustal flexure and the presence of a non-wetting gas phase in pores. A requirement of both abnormal over-pressures and under-pressures is low hydraulic conductivity in either the formation in which the abnormal pressures are observed, or in the overlying and underlying formations. Hydraulic conductivity estimates from straddle packer tests in the DGR boreholes confirm that the hydraulic

  4. Phenols in hydrothermal petroleums and sediment bitumen from Guaymas Basin, Gulf of California

    NASA Technical Reports Server (NTRS)

    Simoneit, B. R.; Leif, R. N.; Ishiwatari, R.

    1996-01-01

    The aliphatic, aromatic and polar (NSO) fractions of seabed petroleums and sediment bitumen extracts from the Guaymas Basin hydrothermal system have been analyzed by gas chromatography and gas chromatography-mass spectrometry (free and silylated). The oils were collected from the interiors and exteriors of high temperature hydrothermal vents and represent hydrothermal pyrolyzates that have migrated to the seafloor by hydrothermal fluid circulation. The downcore sediments are representative of both thermally unaltered and thermally altered sediments. The survey has revealed the presence of oxygenated compounds in samples with a high degree of thermal maturity. Phenols are one class of oxygenated compounds found in these samples. A group of methyl-, dimethyl- and trimethyl-isoprenoidyl phenols (C27-C29) is present in all of the seabed NSO fractions, with the methyl- and dimethyl-isoprenoidyl phenols occurring as major components, and a trimethyl-isoprenoidyl phenol as a minor component. A homologous series of n-alkylphenols (C13-C33) has also been found in the seabed petroleums. These phenols are most likely derived from the hydrothermal alteration of sedimentary organic matter. The n-alkylphenols are probably synthesized under hydrothermal conditions, but the isoprenoidyl phenols are probably hydrothermal alteration products of natural product precursors. The suites of phenols do not appear to be useful tracers of high temperature hydrothermal processes.

  5. Phenols in hydrothermal petroleums and sediment bitumen from Guaymas Basin, Gulf of California.

    PubMed

    Simoneit, B R; Leif, R N; Ishiwatari, R

    1996-01-01

    The aliphatic, aromatic and polar (NSO) fractions of seabed petroleums and sediment bitumen extracts from the Guaymas Basin hydrothermal system have been analyzed by gas chromatography and gas chromatography-mass spectrometry (free and silylated). The oils were collected from the interiors and exteriors of high temperature hydrothermal vents and represent hydrothermal pyrolyzates that have migrated to the seafloor by hydrothermal fluid circulation. The downcore sediments are representative of both thermally unaltered and thermally altered sediments. The survey has revealed the presence of oxygenated compounds in samples with a high degree of thermal maturity. Phenols are one class of oxygenated compounds found in these samples. A group of methyl-, dimethyl- and trimethyl-isoprenoidyl phenols (C27-C29) is present in all of the seabed NSO fractions, with the methyl- and dimethyl-isoprenoidyl phenols occurring as major components, and a trimethyl-isoprenoidyl phenol as a minor component. A homologous series of n-alkylphenols (C13-C33) has also been found in the seabed petroleums. These phenols are most likely derived from the hydrothermal alteration of sedimentary organic matter. The n-alkylphenols are probably synthesized under hydrothermal conditions, but the isoprenoidyl phenols are probably hydrothermal alteration products of natural product precursors. The suites of phenols do not appear to be useful tracers of high temperature hydrothermal processes.

  6. Characterization and mobility of geogenic chromium in soils and river bed sediments of Asopos basin.

    PubMed

    Lilli, Maria A; Moraetis, Daniel; Nikolaidis, Nikolaos P; Karatzas, George P; Kalogerakis, Nicolas

    2015-01-01

    A field and laboratory study was conducted to assess the origin and mobility of CrVI in Asopos basin in Greece. Sampling was designed in such way as to capture the spatial variability of chromium occurring in sediments and soils in different lithological units in the area. Physicochemical and geochemical characterization of surface agricultural soils obtained from river terraces and river bed sediments was conducted in order to determine the natural background of chromium. Lithologies with strong calcareous, siliceous and ultramafic components were identified using principal component analysis. Laboratory mobility studies quantified the rates of chromium sorption and release from soils and their capacity to adsorb chromium. Heavy metal analysis and local geology study support the hypothesis that the main source of chromium is of geogenic origin. Chromium distribution in Asopos river bed was influenced from the eroded products derived from extensive areas with ultramafic rocks the last 5Ma. The mobility studies showed that leaching process was very fast and sorption capacity was significant and capable to retain chromium in case of waste release in the river. Finally the mobility of chromium release is limited due to existing attenuation capacity controlled by ferric oxides coatings on the soil and sediments.

  7. 241Pu and 241Am in sediments from coastal basins off California and Mexico

    NASA Astrophysics Data System (ADS)

    Koide, Minoru; Goldberg, Edward D.; Hodge, Vernon F.

    1980-07-01

    In sediments deposited in the coastal basins off the western North American continent since the early 1960's, there is more 241Am activity than one would predict if its presence was solely due to the decay of 241Pu that was produced during the testing of weapons in 1961-1962 (taken as July 1, 1962 for calculations). This excess can be accounted for by the decay of 241Pu, if pre-1962 fallout (fallout from the pre-moratorium testing) has been continuously introduced into the recent sediments along with fallout from post-moratorium testing. This hypothesis is supported by the plutonium depth profiles which do not reflect direct fallout from the atmosphere, as characterized by two peaks corresponding to the two major weapons testing periods, but continuously increasing plutonium and americium concentrations from 1954 to 1974. Thus, the nuclides may be coming from a large reservoir that has accumulated and mixed fallout since 1952. Such a concentration gradient for all of the nuclides requires their immobilization in the sediment after deposition.

  8. Phenols in hydrothermal petroleums and sediment bitumen from Guaymas Basin, Gulf of California.

    PubMed

    Simoneit, B R; Leif, R N; Ishiwatari, R

    1996-01-01

    The aliphatic, aromatic and polar (NSO) fractions of seabed petroleums and sediment bitumen extracts from the Guaymas Basin hydrothermal system have been analyzed by gas chromatography and gas chromatography-mass spectrometry (free and silylated). The oils were collected from the interiors and exteriors of high temperature hydrothermal vents and represent hydrothermal pyrolyzates that have migrated to the seafloor by hydrothermal fluid circulation. The downcore sediments are representative of both thermally unaltered and thermally altered sediments. The survey has revealed the presence of oxygenated compounds in samples with a high degree of thermal maturity. Phenols are one class of oxygenated compounds found in these samples. A group of methyl-, dimethyl- and trimethyl-isoprenoidyl phenols (C27-C29) is present in all of the seabed NSO fractions, with the methyl- and dimethyl-isoprenoidyl phenols occurring as major components, and a trimethyl-isoprenoidyl phenol as a minor component. A homologous series of n-alkylphenols (C13-C33) has also been found in the seabed petroleums. These phenols are most likely derived from the hydrothermal alteration of sedimentary organic matter. The n-alkylphenols are probably synthesized under hydrothermal conditions, but the isoprenoidyl phenols are probably hydrothermal alteration products of natural product precursors. The suites of phenols do not appear to be useful tracers of high temperature hydrothermal processes. PMID:11541747

  9. Sedimentation, depositional environment and diagenesis of Eocene biosiliceous deposits in Gafsa basin (southern Tunisia)

    NASA Astrophysics Data System (ADS)

    Henchiri, Mohsen

    2007-11-01

    The sedimentary rocks of the Metlaoui Formation in the Gafsa basin (southern Tunisia), which may be grouped in three units: the basal (Thèlja), middle (Chouabine) and upper unit (Kef Eddour), provide a record of preserved sedimentary, authigenic and biological processes. This paper presents the findings of sedimentological investigations of the biosiliceous deposits of the middle unit. This unit contains either well-preserved (Opal-A) or diagenetically altered (Opal-CT, clinoptilolite, quartz and even clays) diatom frustules. Such diagenetic changes are commonly described in marine and lacustrine biosiliceous deposits. The fossil content of theses diatomaceous layers implies shallow-marine conditions. The opal-rich sediments, and the associated facies record the transgressive transitions associated with high organic productivity, probably enhanced by seasonal input of nutrients, and high sea level stands, and a close association with stratified water column conditions. The formation of bedded diatomaceous sediments is known to require either high organic productivity or anoxic conditions in bottom/intermediate water, and eventually both processes. The initial organic content of the biogenic deposits was impoverished in early stages of sedimentation and diagenesis. A large part of the organic matter could have been destroyed during early diagenetic processes and from further oxidation in outcrops.

  10. Seismic stratigraphy and sedimentation of Magdalena Fan, Southern Colombian Basin, Caribbean Sea

    SciTech Connect

    Kolla, V.; Buffler, R.T.; Ladd, J.W.

    1984-03-01

    Analysis of all available seismic data from the Magdalena Fan in the southern Colombian basin, Caribbean Sea, allows subdivision of the sedimentary section into six seismic sequences (units). Although sediments were deposited in the present-day Magdalena Fan region since about Late Cretaceous, terrigenous sedimentation became significant only in the late Cenozoic during deposition of the upper three sequences associated with the uplifts of the Andes. These upper three sequences comprise the Magdalena Fan proper. The uppermost sequence probably represents the last main phase of sedimentation subsequent to the major uplift of the Andes in the Pliocene. The morphologic and shallow acoustic (3.5 kHz) characteristics of this fan unit are: upper fan, 1:60-1:110 gradients, channels having well-developed levees, and several subbottom reflectors in all areas except in channels; middle fan, 1:110-1:200 gradients, numerous channels with very subdued levees, and several to few subbottom reflectors; lower fan, < 1:250 gradients, small channels, relatively smooth sea floor, and few or no subbottom reflectors.

  11. Diversity and distributional patterns of ciliates in Guaymas Basin hydrothermal vent sediments.

    PubMed

    Coyne, Kathryn J; Countway, Peter D; Pilditch, Conrad A; Lee, Charles K; Caron, David A; Cary, Stephen C

    2013-01-01

    Little is known about protists at deep-sea hydrothermal vents. The vent sites at Guaymas Basin in the Gulf of California are characterized by dense mats of filamentous pigmented or nonpigmented Beggiatoa that serve as markers of subsurface thermochemical gradients. We constructed 18S rRNA libraries to investigate ciliate assemblages in Beggiatoa mats and from bare sediments at the Guaymas vent site. Results indicated a high diversity of ciliates, with 156 operational taxonomic units identified in 548 sequences. Comparison between mat environments demonstrated that ciliate and bacterial assemblages from pigmented mats, nonpigmented mats, and bare sediments were significantly different and highly correlated with bacterial assemblages. Neither bacterial nor ciliate assemblages were correlated with environmental factors. The most abundant ciliates at Guaymas were more likely to be represented in clone libraries from other hydrothermal, deep-sea, and/or anoxic or microaerophilic environments, supporting the hypothesis that these ciliate species are broadly distributed. The orange mat environment included a higher proportion of ciliate sequences that were more similar to those from other environmental studies than to cultured ciliate species, whereas clone libraries from bare sediments included sequences that were the most highly divergent from all other sequences and may represent species that are endemic to Guaymas.

  12. Cable Bacteria Control Iron-Phosphorus Dynamics in Sediments of a Coastal Hypoxic Basin.

    PubMed

    Sulu-Gambari, Fatimah; Seitaj, Dorina; Meysman, Filip J R; Schauer, Regina; Polerecky, Lubos; Slomp, Caroline P

    2016-02-01

    Phosphorus is an essential nutrient for life. The release of phosphorus from sediments is critical in sustaining phytoplankton growth in many aquatic systems and is pivotal to eutrophication and the development of bottom water hypoxia. Conventionally, sediment phosphorus release is thought to be controlled by changes in iron oxide reduction driven by variations in external environmental factors, such as organic matter input and bottom water oxygen. Here, we show that internal shifts in microbial communities, and specifically the population dynamics of cable bacteria, can also induce strong seasonality in sedimentary iron-phosphorus dynamics. Field observations in a seasonally hypoxic coastal basin demonstrate that the long-range electrogenic metabolism of cable bacteria leads to a dissolution of iron sulfides in winter and spring. Subsequent oxidation of the mobilized ferrous iron with manganese oxides results in a large stock of iron-oxide-bound phosphorus below the oxic zone. In summer, when bottom water hypoxia develops and cable bacteria are undetectable, the phosphorus associated with these iron oxides is released, strongly increasing phosphorus availability in the water column. Future research should elucidate whether formation of iron-oxide-bound phosphorus driven by cable bacteria, as observed in this study, contributes to the seasonality in iron-phosphorus cycling in aquatic sediments worldwide.

  13. Connectivity and colluvial sediment dynamics in the Saldur River basin, Eastern Italian Alps

    NASA Astrophysics Data System (ADS)

    Brardinoni, Francesco; Scotti, Riccardo; Cavalli, Marco; Mair, Volkmar

    2015-04-01

    We present an integrated approach that aims to: (i) document the spatial distribution of mass-wasting activity and sediment production in the Saldur River basin (97 km2); (ii) detect causal linkages between mass-wasting intensity and the potential spatial distribution of discontinuous permafrost; (iii) identify source-to-sink colluvial sedimentary pathways as modulated by the spatial organization of active and relict glacial and periglacial depositional landforms; and (iv) test the reliability of a geomorphometry-based index of sediment connectivity. In so doing we compare spatial patterns of process-based and structural geomorphic connectivity. To these ends, we map rock glaciers, protalus ramparts and moraines, and compile a field- and air photo-based multi-temporal (1959-1969-1982-1997-2000-2006-2008-2011) inventory of colluvial sediment sources. We then combine these data with two historical datasets of debris flow and landslide events (both implemented and maintained by the Autonomous Province of Bolzano) and analyse mass-wasting spatial distribution and intensity in relation to proximity to glacier fronts, intact and relict periglacial landforms, and a permafrost index map (i.e., PermaNET; http://www.permanet-alpinespace.eu/). This work is part of SedAlp (www.sedalp.eu), a project funded through the Alpine Space Programme.

  14. Discharge and sediment loads in the Boise River drainage basin, Idaho 1939-40

    USGS Publications Warehouse

    Love, S.K.; Benedict, Paul Charles

    1948-01-01

    The Boise River project is a highly developed agricultural area comprising some 520 square miles of valley and bench lands in southwestern Idaho. Water for irrigation is obtained from the Boise River and its tributaries which are regulated by storage in Arrow Rock and Deer Flat reservoirs. Distribution of water to the farms is effected by 27 principal canals and several small farm laterals which divert directly from the river. The- New York Canal, which is the largest, not only supplies water to smaller canals and farm laterals, but also is used to fill Deer Flat Reservoir near Nampa from which water is furnished to farms in the lower valley. During the past 15 years maintenance costs in a number of those canals have increased due to deposition of sediment in them and in the river channel itself below the mouth of Moore Creek. Interest in determining the runoff and sediment loads from certain areas in the Boise River drainage basin led to an investigation by the Flood Control Coordinating Committee of the Department of Agriculture. Measurements of daily discharge and sediments loads were made by the Geological Survey at 13 stations in the drainage basin during the 18-month period ended June 30, 1940. The stations were on streams in areas having different kinds of vegetative cover and subjected to different kinds of land-use practice. Data obtained during the investigation furnish a basis for certain comparisons of runoff and sediment loads from several areas arid for several periods of time. Runoff measured at stations on the. Boise River near Twin Springs and on Moore Creek near Arrow Rock was smaller during 1939 than during 1940 and was below the average annual runoff for the period of available record. Runoff measured at the other stations on the project also was smaller during 1939 than during 1940 and probably did not exceed the average for the previous 25 years. The sediment loads measured during the spring runoff in 1939 were smaller at most stations than

  15. Bridging the gap between small and large scale sediment budgets? - A scaling challenge in the Upper Rhone Basin, Switzerland

    NASA Astrophysics Data System (ADS)

    Schoch, Anna; Blöthe, Jan; Hoffmann, Thomas; Schrott, Lothar

    2016-04-01

    A large number of sediment budgets have been compiled on different temporal and spatial scales in alpine regions. Detailed sediment budgets based on the quantification of a number of sediment storages (e.g. talus cones, moraine deposits) exist only for a few small scale drainage basins (up to 10² km²). In contrast, large scale sediment budgets (> 10³ km²) consider only long term sediment sinks such as valley fills and lakes. Until now, these studies often neglect small scale sediment storages in the headwaters. However, the significance of these sediment storages have been reported. A quantitative verification whether headwaters function as sediment source regions is lacking. Despite substantial transport energy in mountain environments due to steep gradients and high relief, sediment flux in large river systems is frequently disconnected from alpine headwaters. This leads to significant storage of coarse-grained sediment along the flow path from rockwall source regions to large sedimentary sinks in major alpine valleys. To improve the knowledge on sediment budgets in large scale alpine catchments and to bridge the gap between small and large scale sediment budgets, we apply a multi-method approach comprising investigations on different spatial scales in the Upper Rhone Basin (URB). The URB is the largest inneralpine basin in the European Alps with a size of > 5400 km². It is a closed system with Lake Geneva acting as an ultimate sediment sink for suspended and clastic sediment. We examine the spatial pattern and volumes of sediment storages as well as the morphometry on the local and catchment-wide scale. We mapped sediment storages and bedrock in five sub-regions of the study area (Goms, Lötschen valley, Val d'Illiez, Vallée de la Liène, Turtmann valley) in the field and from high-resolution remote sensing imagery to investigate the spatial distribution of different sediment storage types (e.g. talus deposits, debris flow cones, alluvial fans). These sub

  16. Risk Evaluation of Multiple Hazards during Sediment and Water Related Disasters in a Small Basin

    NASA Astrophysics Data System (ADS)

    Yamanoi, Kazuki; Fujita, Masaharu

    2016-04-01

    To reduce human damage due to sediment and water related disasters induced by heavy rainfall, warning and evacuation system is very important. In Japan, the Meteorological Agency issues the sediment disaster alert when the potential of sediment disaster increases. Following the alert, local government issues evacuation advisory considering the alert and premonitory phenomena. However, it is very difficult for local people to perceive the dangerousness around them because the alert and advisory do not contain any definite information. Therefore, they sometimes misjudge the evacuation action. One reason of this is not only crucial hazards but also relatively small-scale multiple hazards take place and rise evacuation difficulties during sediment and water related disaster. Examples of small-scale hazards include: rainfall-associated hazards such as poor visibility or road submergence; landslide-associated hazards such as slope failure or sediment inflow; and flood-associated hazards such as overtopping of river dike, inundation, or destruction of bridges. The purpose of this study was to estimate the risk of multiple hazards during disaster events by numerical simulation. We applied the integrated sediment runoff model on unit channels, unit slopes, and slope units to an actual sediment and water related disaster occurred in a small basin in Tamba city, Hyogo, Japan. The maximum rainfall per hour was 91 mm (17/09/2014 2:00˜3:00) and the maximum daily precipitation was 414mm. The integrated model contains semi-physical based landslide prediction (sediment production) model, rainfall runoff model employing the kinematic wave method, model of sediment supply to channels, and bedload and suspended sediment transport model. We evaluated the risk of rainfall-associated hazards in each slope unit into 4 levels (Level I ˜ IV) using the rainfall intensity Ir [mm/hour]. The risk of flood- associated hazards were also estimated using the ratio of calculated water level and

  17. Sequence Stratigraphic Analysis of Tertiary Wedges and Sediments in Sørvestsnaget Basin, SW Barents Sea

    NASA Astrophysics Data System (ADS)

    Harishidayat, D.; Omosanya, K. O.; Johansen, S. E.; Abrahamson, P.

    2015-12-01

    The Sørvestsnaget Basin is a Cenozoic depocenter in Southwestern Barents Sea formed along the North-South Senja fault. Previous research works in this area have identified a thick succession of Tertiary wedges sourced potentially from the Stappen High. This study is aimed at evaluating the evolution of the Tertiary deposits in the Sørvestsnaget Basin using sequence stratigraphic approach. Five sequences were interpreted from recently acquired high-resolution 2D seismic reflection data. Lithology and biostratigraphic information was obtained from two boreholes in the study area, 7316/5-1 and 7216/11-1S. The sequences were separated into maximum flooding surface, condensed section, and a sequence boundary that correlate from wells to seismic for hundreds of kilometers. The first sequence is the base of the Paleogene unit revealed as low and high basement configuration. This sequence is succeeded by a transgressive system tract (TST) dominated by deposition of deep marine shale after a relative sea-level rise. Biostratigraphy data from well 7216/11-1S revealed stratigraphic breaks on the Late Eocene to Miocene age condensed section. Uplift of the marginal high in Oligocene to Miocene times influenced the development of an early highstand system tract (EHST) during Neogene age. This is followed by deposition of shallow marine sediments and emergence of a late highstand system tract (LHST) in early Quaternary. The LHST developed in a glacio-marine environment. Relatively low sea-level fall during middle Quaternary forced the development of a shelf margin towards the south. The top of the shelf margin system tract (SMST) was eroded by the Upper Regional Unconformity (URU). In Late Quaternary, the Sørvestsnaget Basin witnessed a relatively sea-level rise evidenced by the back-stepping sequences above the URU on seismic section. This is the last transgressive system tract (TST). This work has shown that the Sørvestsnaget Basin has recorded fluctuating sea-level rise

  18. Porewater pH and authigenic phases formed in the uppermost sediments of the Santa Barbara Basin

    NASA Astrophysics Data System (ADS)

    Reimers, Clare E.; Ruttenberg, Kathleen C.; Canfield, Donald E.; Christiansen, Matthew B.; Martin, Jonathan B.

    1996-11-01

    In this paper porewater and solid phase analyses are used in combination with in situ O 2 and pH microelectrode measurements to characterize early diagenetic processes in the uppermost sediments of the Santa Barbara Basin, California. Rapid reduction of dissolved oxygen, nitrate, solid phase manganese and iron, and dissolved sulfate is observed. Between sediment depths of 0 and 2 cm, reductive solubilization of ferric iron phases releases Fe 2+, adsorbed phosphate, and fluoride to the porewaters and contributes to a sharp increase in porewater pH. Between 2 and 4 cm, sulfate reduction rates peak, pH levels off, and acid volatile sulfides and pyrite become the dominant forms of solid phase iron. Saturation state calculations, which depend largely on pH, indicate that the porewaters of the Santa Barbara Basin become saturated with respect to carbonate fluorapatite and calcite within the first 0.25 mm of the sediment and are highly supersaturated by and below 2 cm. In spite of this result, porewater evidence of phosphate and fluoride removal into a solid phase is observed only in the first ˜5 cm of some cores, whereas dissolved Ca profiles suggest dispersed calcite precipitation throughout the sediment column. This finding is interpreted as an indication of the nonsteady state nature of the surface reactions that may, given sufficient nucleation sites and time, lead to carbonate fluorapatite genesis in anoxic sediments. Finally, microelectrode pH profiles from two other basins in the California Borderlands are presented. These demonstrate that the porewaters of the Santa Barbara Basin are more alkaline than those of other basins. This outcome is attributed to the lack of particle mixing and a unique interplay between Fe liberation and FeS precipitation reactions in the Santa Barbara Basin.

  19. Erosion processes, fluvial sediment transport, and reservoir sedimentation in a part of the Newell and Zayante Creek basins, Santa Cruz County, California

    USGS Publications Warehouse

    Brown, W. M.

    1973-01-01

    The drainage basins upstream from Loch Lomond, a water-supply reservoir on Newell Creek, and a proposed reservoir site on Zayante Creek were investigated for their characteristics with respect to the erosion, transportation, and deposition of sediment. The study area is underlain predominantly by sandstone, siltstone, and shale of Tertiary age that decompose readily into moderately deep soils, friable colluvium, and easily transported sediment particles. The Rices Mudstone and Twobar, Shale Members of the San Lorenzo Formation of Brabb (1964) underlie steep dip slopes in the study area, and probably are the most highly erodible of the several geologic units present there. However, nearly all of the geologic units have shown a propensity for accelerated erosion accompanying the disturbance of the land surface by the roadbuilding practices that predominate over other types of sediment-producing land-use activities in the study area. Sediment transport in the study area was estimated from (1) a reservoir survey of Loch Lomond in 1971 that was compared with a preconstruction survey of 1960, and (2) sampling of sediment transported in suspension by Zayante Creek during the 1970 and 1971 water years. At least 46 acre-feet of sediment accumulated in Loch Lomond in a 10-year period, and an unmeasured quantity of very fine sediment in the form of a thin layer over much of the reservoir bottom was observed. The measured quantity of deposited sediment in a 10-year period represented a sediment yield of about 1,100 tons annually per square mile of drainage basin upstream from the reservoir arms where the major deposition occurred. This sediment occupied less than i percent of the original capacity of Loch Lomond, but the volume of measured sediment deposition is probably conservative in view of the unmeasured deposits observed and a reservoir trap efficiency of about 95 percent. Sediment sampling on Zayante Creek indicated suspended-sediment yields of about 4,570 and 570 tons

  20. Transport of Water, Carbon, and Sediment Through the Yukon River Basin

    USGS Publications Warehouse

    Brabets, Timothy P.; Schuster, Paul F.

    2008-01-01

    INTRODUCTION In 2001, the U.S. Geological Survey (USGS) began a water-quality study of the Yukon River. The Yukon River Basin (YRB), which encompasses 330,000 square miles in northwestern Canada and central Alaska (fig. 1), is one of the largest and most diverse ecosystems in North America. The Yukon River is more than 1,800 miles long and is one of the last great uncontrolled rivers in the world, and is essential to the eastern Bering Sea and Chukchi Sea ecosystems, providing freshwater runoff, sediments, and nutrients (Brabets and others, 2000). Despite its remoteness, recent studies (Hinzman and others, 2005; Walvoord and Striegl, 2007) indicate the YRB is changing. These changes likely are in response to a warming trend in air temperature of 1.7i??C from 1951 to 2001 (Hartmann and Wendler, 2005). As a result of this warming trend, permafrost is thawing in the YRB, ice breakup occurs earlier on the main stem of the Yukon River and its tributaries, and timing of streamflow and movement of carbon and sediment through the basin is changing (Hinzman and others, 2005; Walvoord and Striegl, 2007). One of the most striking characteristics in the YRB is its seasonality. In the YRB, more than 75 percent of the annual streamflow runoff occurs during a five month period, May through September. This is important because streamflow determines when, where, and how much of a particular constituent will be transported. As an example, more than 95 percent of all sediment transported during an average year also occurs during this period (Brabets and others, 2000). During the other 7 months, streamflow, concentrations of sediment and other water-quality constituents are low and little or no sediment transport occurs in the Yukon River and its tributaries. Streamflow and water-quality data have been collected at more than 50 sites in the YRB (Dornblaser and Halm, 2006; Halm and Dornblaser, 2007). Five sites have been sampled more than 30 times and others have been sampled twice

  1. Sensitivity analysis of a sediment dynamics model applied in a Mediterranean river basin: global change and management implications.

    PubMed

    Sánchez-Canales, M; López-Benito, A; Acuña, V; Ziv, G; Hamel, P; Chaplin-Kramer, R; Elorza, F J

    2015-01-01

    Climate change and land-use change are major factors influencing sediment dynamics. Models can be used to better understand sediment production and retention by the landscape, although their interpretation is limited by large uncertainties, including model parameter uncertainties. The uncertainties related to parameter selection may be significant and need to be quantified to improve model interpretation for watershed management. In this study, we performed a sensitivity analysis of the InVEST (Integrated Valuation of Environmental Services and Tradeoffs) sediment retention model in order to determine which model parameters had the greatest influence on model outputs, and therefore require special attention during calibration. The estimation of the sediment loads in this model is based on the Universal Soil Loss Equation (USLE). The sensitivity analysis was performed in the Llobregat basin (NE Iberian Peninsula) for exported and retained sediment, which support two different ecosystem service benefits (avoided reservoir sedimentation and improved water quality). Our analysis identified the model parameters related to the natural environment as the most influential for sediment export and retention. Accordingly, small changes in variables such as the magnitude and frequency of extreme rainfall events could cause major changes in sediment dynamics, demonstrating the sensitivity of these dynamics to climate change in Mediterranean basins. Parameters directly related to human activities and decisions (such as cover management factor, C) were also influential, especially for sediment exported. The importance of these human-related parameters in the sediment export process suggests that mitigation measures have the potential to at least partially ameliorate climate-change driven changes in sediment exportation.

  2. Analysis of suspended-sediment concentrations and radioisotope levels in the Wild Rice River basin, northwestern Minnesota, 1973-98

    USGS Publications Warehouse

    Brigham, Mark E.; McCullough, Carolyn J.; Wilkinson, Philip M.

    2001-01-01

    We examined historical suspended-sediment data and activities of fallout radioisotopes (lead-210 [210Pb], cesium-137 [137Cs], and beryllium-7 [7Be]) associated with suspended sediments and source-area sediments (cultivated soils, bank material, and reference soils) in the Wild Rice River Basin, a tributary to the Red River of the North, to better understand sources of suspended sediment to streams in the region. Multiple linear regression analysis of suspended-sediment concentrations from the Wild Rice River at Twin Valley, Minnesota indicated significant relations between suspended-sediment concentrations and streamflow. Flow-adjusted sediment concentrations tended to be slightly higher in spring than summer-autumn. No temporal trends in concentration were observed during 1973-98. The fallout radioisotopes were nearly always detectable in suspended sediments during spring-summer 1998. Mean 210Pb and 7Be activities in suspended sediment and surficial, cultivated soils were similar, perhaps indicating little dilution of suspended sediment from low-isotopic-activity bank sediments. In contrast, mean 137Cs activities in suspended sediment indicated a mixture of sediment originating from eroded soils and from eroded bank material, with bank material being a somewhat more important source upstream of Twin Valley, Minnesota; and approximately equal fractions of bank material and surficial soils contributing to the suspended load downstream at Hendrum, Minnesota. This study indicates that, to be effective, efforts to reduce sediment loading to the Wild Rice River should include measures to control soil erosion from cultivated fields.

  3. Effects of hydrology, watershed size, and agricultural practices on sediment yields in two river basins in Iowa and Mississippi

    USGS Publications Warehouse

    Merten, Gustavo Henrique; Welch, Heather L.; Tomer, M.D.

    2016-01-01

    The specific sediment yield (SSY) from watersheds is the result of the balance between natural, scale-dependent erosion and deposition processes, but can be greatly altered by human activities. In general, the SSY decreases along the course of a river as sediments are trapped in alluvial plains and other sinks. However, this relation between SSY and basin area can actually be an increasing one when there is a predominance of channel erosion relative to hillslope erosion. The US Geological Survey (USGS) conducted a study of suspended sediment in the Iowa River basin (IRB), Iowa, and the Yazoo River basin (YRB), Mississippi, from 2006 through 2008. Within each river basin, the SSY from four largely agricultural watersheds of various sizes (2.3 to 35,000 km2 [0.9 to 13,513 mi2]) was investigated. In the smallest watersheds, YRB sites had greater SSY compared to IRB sites due to higher rain erosivity, more erodible soils, more overland flow, and fluvial geomorphological differences. Watersheds in the YRB showed a steady decrease in SSY with increasing drainage basin area, whereas in the IRB, the maximum SSY occurred at the 30 to 500 km2 (11.6 to 193 mi2) scale. Subsurface tile drainage and limits to channel downcutting restrict the upstream migration of sediment sources in the IRB. Nevertheless, by comparing the SSY-basin size scaling relationships with estimated rates of field erosion under conservation and conventional tillage treatments reported in previous literature, we show evidence that the SSY-basin size relationship in both the IRB and YRB remain impacted by historical erosion rates that occurred prior to conservation efforts.

  4. Connectivity and scale effect on sediment fluxes dynamic from the hillslope to the river basin

    NASA Astrophysics Data System (ADS)

    Cerdan, Olivier; Landemaine, Valentin; Vandromme, Rosalie; Gay, Aurore; Laignel, Benoit

    2016-04-01

    The phenomena of erosion and sediment transport are often observed with a time lag and / or space within a watershed, especially between the upstream and downstream areas. This difference between runoff and erosion assessments that depends on the size of observation is commonly called the "scale effect". This effect has often been studied globally and reduced runoff and erosion rates are generally reported as one moves from the local to the regional level. To quantify the scale effect, local erosion models are often linked to the empirical concept of SDR (Sediment Delivery Ratio): the ratio of exported sediment at the outlet of a drainage system on the gross erosion that occurred locally. This empirical parameter is used as a connectivity factor to estimate the contribution of net soil losses to sedimentary basins exports. A recent renewed interest on these topics has led the development of more or less elaborate variants that propose a conceptualization of the (es) connectivity (s) of the landscape to describe the sedimentary flows within watersheds. In general, these concepts allow apprehending the spatial variability of flow in heterogeneous environments and for events / climates not too extreme. Their use is more difficult when the flows are constrained by the production process. A limit also appears when trying to cover too large a range of spatial scales, because beyond a spatial succession of (re) detachment and deposition processes a new nature of process can emerge. We will rely on several measured database of erosion / sediment transport at different scales and in diverse geomorphological contexts to illustrate and discuss the relevance of these concepts.

  5. Fungal diversity from deep marine subsurface sediments (IODP 317, Canterbury Basin, New Zealand)

    NASA Astrophysics Data System (ADS)

    Redou, V.; Arzur, D.; Burgaud, G.; Barbier, G.

    2012-12-01

    Recent years have seen a growing interest regarding micro-eukaryotic communities in extreme environments as a third microbial domain after Bacteria and Archaea. However, knowledge is still scarce and the diversity of micro-eukaryotes in such environments remains hidden and their ecological role unknown. Our research program is based on the deep sedimentary layers of the Canterbury Basin in New Zealand (IODP 317) from the subsurface to the record depth of 1884 meters below seafloor. The objectives of our study are (i) to assess the genetic diversity of fungi in deep-sea sediments and (ii) identify the functional part in order to better understand the origin and the ecological role of fungal communities in this extreme ecosystem. Fingerprinting-based methods using capillary electrophoresis single-strand conformation polymorphism and denaturing high-performance liquid chromatography were used as a first step to raise our objectives. Molecular fungal diversity was assessed using amplification of ITS1 (Internal Transcribed Spacer 1) as a biomarker on 11 samples sediments from 3.76 to 1884 meters below seafloor. Fungal molecular signatures were detected throughout the sediment core. The phyla Ascomycota and Basidiomycota were revealed with DNA as well as cDNA. Most of the phylotypes are affiliated to environmental sequences and some to common fungal cultured species. The discovery of a present and metabolically active fungal component in this unique ecosystem allows some interesting first hypotheses that will be further combined to culture-based methods and deeper molecular methods (454 pyrosequencing) to highlight essential informations regarding physiology and ecological role of fungal communities in deep marine sediments.

  6. Multiple ash layers in late Quaternary sediments from the Central Indian Basin

    NASA Astrophysics Data System (ADS)

    Mascarenhas-Pereira, M. B. L.; Nagender Nath, B.; Iyer, S. D.; Borole, D. V.; Parthiban, G.; Jijin, R.; Khedekar, V.

    2016-04-01

    We have investigated three sediment cores collected from water depths > 5000 m along the transect 76°30‧E in close proximity to a fracture zone in the Central Indian Basin (CIB). The cores yielded five volcanic horizons of which four have visual and dispersed shards. Rhyolitic glass shards of bubble wall, platy, angular and blocky types were retrieved from various stratigraphic horizons in the cores. The abundance of glass shards, composition of bulk sediments, and 230Thexcess ages of the host sediments were used to distinguish the volcanic horizons. Of the four volcanic horizons, three are now newly reported and correspond to ages of ~ 85, 107-109 and 142-146 ka while the fourth horizon is of 70-75 ka. By using trace element ratios and Cr and Nb-based normative calculations, cryptotephra has been identified for the first time from the CIB sediment. The cryptotephra forms the fifth ash horizon and is of ~ 34 ka. A comparison with the published data on volcanic tephra in and around the Indian Ocean indicate the shard rich horizon (SRH) of 70-75 ka to resemble the Younger Toba Tuffs (YTT), while the other volcanic horizons that were deposited during different time periods do not correlate with any known marine or terrestrial records. These tephra layers have produced a tephrostratigraphic framework across the tectonically and volcanically complex regions of the CIB. Due to the lack of terrestrial equivalents of these tephra, it is hypothesized that the newly found volcanic horizons may have been derived from submarine volcanic eruptions. Multiple layers of submarine volcaniclastic deposits found at water depths as great as 5300 m reaffirm the growing belief that submarine phreatomagmatic eruptions are much more common in the intraplate region of the Indian Ocean than previously reported.

  7. Geochemical evaluation of present-day Tuul River sediments, Ulaanbaatar basin, Mongolia.

    PubMed

    Dalai, Banzragch; Ishiga, Hiroaki

    2013-03-01

    The Tuul River flows through the Ulaanbaatar basin of Mongolia and is the main source of water for the capital city, Ulaanbaatar. The Tuul catchment can be divided into three parts around Ulaanbaatar (upper, middle, and lower), according to the extent of urbanization. Sixteen surface water and groundwater samples were collected to evaluate present-day water quality and 34 stream sediment samples taken to examine their geochemical composition in relation to provenance and to assess the impact of urban activity on heavy metal accumulation. Groundwater quality in the upper and central water sources was adequate, but high concentrations of NO (3) (-) were found in the lower water source. Heavy metal concentrations in the sediments are evaluated by comparison with average upper continental crust (UCC) values, coupled with ecological risk assessment by reference to sediment quality guidelines (SQG). The results show average abundances of potentially toxic metals such as As, Pb, Zn, Cu, Ni, Cr, and V are higher in the middle part (within the city) than in the upper and lower parts. However, all three parts show depletion in some chalcophile and high field strength elements (Cu, Ni, Cr, Sr, Nb, Zr, Th, Sc) relative to UCC, indicating that the river sediments were derived from a highly felsic crustal source. The assessment using SQG shows As and Cr are present in levels that cause adverse aquatic biological effects. Although concentrations of Pb, Zn, Cu, and Ni are generally below their respective threshold effect levels, in the middle reaches, values increase and border on the probable effect level. This suggests significant anthropogenic contamination in the urban areas, increasing values above a naturally low regional background.

  8. Global Climate Change and Sedimentation Patterns in the Neogene Baringo Basin, Central Kenya Rift

    NASA Astrophysics Data System (ADS)

    Deino, A. L.; Kingston, J. D.; Wilson, K. E.; Hill, A.

    2010-12-01

    The Tugen Hills are part of a ~100 km N-S tilted fault block, just west of Lake Baringo within the Central Kenyan Rift Valley. Sediments exposed in this block span the last 16 Ma and have yielded abundant and diverse fossil assemblages including a number of hominoid and hominid specimens. Much research has also focused on documenting the paleoecology of the succession through analyses of fossil floral, faunal, and biogeochemical proxies. Data from the Tugen Hills have revealed a complex evolutionary history of ecosystems characterized by spatial and temporal heterogeneity with no clear evidence of any long-term trends. While these studies suggest that the patterns of heterogeneity may be shifting at short time-scales (104-105 ka), limited temporal resolution has until now generally precluded assessments of environmental change at these scales. Recently published investigations in the Baringo Basin have provided evidence of orbitally mediated environmental change over periods which include hominid fossil localities (Deino et al., 2006; Kingston et al., 2007). The Baringo data represent the only empirical evidence for significant local environmental shifts that can directly be correlated with insolation patterns in equatorial Africa. Sedimentation patterns in the Baringo Basin between ca. 2.70 and 2.55 Ma, controlled by climatic factors, provide a detailed paleoenvironmental record including a sequence of diatomites that record rhythmic cycling of major freshwater lake systems consistent with ~23 kyr Milankovitch precessional periodicity modulated by eccentricity. The timing of the paleolakes most closely approximates insolation maximum for the June/July 30○N insolation curve, suggesting that precipitation patterns in the region are controlled by the African monsoon system. More recent fieldwork has identified older sequences that similarly demonstrate rhythmic cycling of freshwater lake systems. Preliminary 40Ar/39Ar dating of intercalated tephra reveals that

  9. Thermal alteration of organic matter in recent marine sediments. 1: Pigments. [photosynthetic pigments from Tanner Basin off Southern California

    NASA Technical Reports Server (NTRS)

    Ikan, R.; Aizenshtat, Z.; Baedecker, M. J.; Kaplan, I. R.

    1974-01-01

    Sediment from Tanner Basin, the outer continental shelf off Southern California, was analyzed for photosynthetic pigments and their derivatives, namely carotenes and chlorins. Samples of the sediment were also exposed to raised temperatures (65, 100, 150 C) for various periods of time (1 week, 1 month, 2 months). Analysis of the heat-treated sediment revealed the presence of alpha-ionene and 2,6-dimethylnapthalene, thermal degradation products of Betacarotente. Chlorins were converted to nickel porphyrins of both DPEP and etio series. Possible mechanisms of these transformations are presented.

  10. Strontium Isotope Dating of Metalliferous Sediment in the SW Pacific Basin

    NASA Astrophysics Data System (ADS)

    Stancin, A. M.; Gleason, J. D.; Owen, B. M.; Rea, D. K.; Moore, T. C.; Hendy, I. L.; Lyle, M. W.; Blum, J. D.

    2007-12-01

    A 2 million km2 region virtually devoid of sediment was identified in the remote SW Pacific Basin during the TUIM- 3 2005 drill site survey cruise. This region, termed the "South Pacific Bare Zone", comprises ocean floor dating back to the Late Cretaceous. Within the Bare Zone, a small (1km2) abyssal valley containing sediment to a depth of 24 m was sampled using a large diameter piston core (MV0502-15JC, 31 ° 42.194'S, 143 ° 30.331'W), leading to recovery of 8.35 m of metalliferous sediment at 5082 m water depth. Fish-teeth Sr-isotope stratigraphy reveals a continuous record of sedimentation from 31 Ma to present at this site. The fish teeth age-depth profile and INAA geochemistry reveal an exponentially decreasing hydrothermal flux, with sedimentation rates approaching 0.05 mm/kyr after 20 Ma. The source of hydrothermal activity at this site was likely the Pacific- Farallon Ridge, which went extinct at 20 Ma. A second piston core (MV0502-16JC; 28 ° 05.151'S, 140 ° 14.140'W) was collected near MacDonald Seamounts located on the southeastern end of the Cook-Austral island chain outside the Bare Zone and recovered 10.5 m of hydrothermal sediment and biogenic ooze. The lower 65 cm of the core consists of a coccolith ooze. From 10 mbsf depth to 1.5 mbsf depth, the core contians reddish black zeolitic clay, while the upper 1.5 mbsf contains biogenic ooze associated with abundant Late Pleistocene foraminifera remains. Concordant nannofossil and fish teeth ages at the base of the core (27-28 Ma), and Pleistocene ages near the top of the core reinforce the validity of the Sr fish teeth method for dating hydrothermal cores. These independent records suggest that regional hydrothermal activity during the Oligocene may have been related to a series of late Eocene/early Oligocene ridge jumps, propagating rifts and seafloor spreading centers that accompanied large-scale plate tectonic reorganization of South Pacific seafloor.

  11. Phosphorus geochemistry of recent sediments in the South Basin of Lake Winnipeg

    USGS Publications Warehouse

    Mayer, T.; Simpson, S.L.; Thorleifson, L.H.; Lockhart, W.L.; Wilkinson, Philip M.

    2006-01-01

    Lake Winnipeg supports the largest commercial fishery on Canadian Prairies. It has been influenced by a variety of environmental forces and anthropogenic activities. To gain a better understanding of recent changes in nutrient status of the lake, it is important to reconstruct its previous history from sedimentary records. Lacustrine sediments are known to be an important sink of many dissolved and suspended substances, including phosphorus, hence, they provide a permanent historical record of changes occurring in the lake. These changes may be induced by natural factors or by anthropogenic activities in the watershed. Phosphorus profiles from dated sediment cores collected in 1999 and 1994 from the South Basin of Lake Winnipeg were investigated to determine phosphorus enrichment in recent sediments. To interpret the nutrient status and depositional conditions responsible for the trends in total phosphorus, three operationally defined forms of phosphorus (P) were determined: non-apatite inorganic P, apatite P, and organic P. Significant increases in sediment phosphorus concentrations were observed in the uppermost 20 cm of the cores and several anomalies were observed at depth. A doubling in total phosphorus relative to aluminum over the last fifty years is largely due to increases in the non-apatite inorganic fraction, suggesting that much of sedimentary phosphorus increase is attributable to changes in the nutrient status of the water column related to anthropogenic inputs. Organic phosphorus exhibits a subtle increase in the upper 20 cm of the gravity cores, likely due to increases in the primary productivity of the lake. Except for the slight increase in deeper sediments, apatite phosphorus, which is thought to be of detrital origin, remained fairly constant over the length of the cores. Anomalous spikes in phosphorus concentrations deeper in the cores, comprised mainly of the non-apatite inorganic phosphorus fraction, likely resulted from natural variation in

  12. Eddy-driven sediment transport in the Argentine Basin: Is the height of the Zapiola Rise hydrodynamically controlled?

    NASA Astrophysics Data System (ADS)

    Weijer, Wilbert; Maltrud, Mathew E.; Homoky, William B.; Polzin, Kurt L.; Maas, Leo R. M.

    2015-03-01

    In this study, we address the question whether eddy-driven transports in the Argentine Basin can be held responsible for enhanced sediment accumulation over the Zapiola Rise, hence accounting for the existence and growth of this sediment drift. To address this question, we perform a 6 year simulation with a strongly eddying ocean model. We release two passive tracers, with settling velocities that are consistent with silt and clay size particles. Our experiments show contrasting behavior between the silt fraction and the lighter clay. Due to its larger settling velocity, the silt fraction reaches a quasisteady state within a few years, with abyssal sedimentation rates that match net input. In contrast, clay settles only slowly, and its distribution is heavily stratified, being transported mainly along isopycnals. Yet, both size classes display a significant and persistent concentration minimum over the Zapiola Rise. We show that the Zapiola Anticyclone, a strong eddy-driven vortex that circulates around the Zapiola Rise, is a barrier to sediment transport, and hence prevents significant accumulation of sediments on the Rise. We conclude that sediment transport by the turbulent circulation in the Argentine Basin alone cannot account for the preferred sediment accumulation over the Rise. We speculate that resuspension is a critical process in the formation and maintenance of the Zapiola Rise.

  13. Characterizing changes in streamflow and sediment supply in the Sacramento River Basin, California, using hydrological simulation program—FORTRAN (HSPF)

    USGS Publications Warehouse

    Stern, Michelle A.; Flint, Lorraine E.; Minear, Justin T.; Flint, Alan L.; Wright, Scott A.

    2016-01-01

    A daily watershed model of the Sacramento River Basin of northern California was developed to simulate streamflow and suspended sediment transport to the San Francisco Bay-Delta. To compensate for sparse data, a unique combination of model inputs was developed, including meteorological variables, potential evapotranspiration, and parameters defining hydraulic geometry. A slight decreasing trend of sediment loads and concentrations was statistically significant in the lowest 50% of flows, supporting the observed historical sediment decline. Historical changes in climate, including seasonality and decline of snowpack, contribute to changes in streamflow, and are a significant component describing the mechanisms responsible for the decline in sediment. Several wet and dry hypothetical climate change scenarios with temperature changes of 1.5 °C and 4.5 °C were applied to the base historical conditions to assess the model sensitivity of streamflow and sediment to changes in climate. Of the scenarios evaluated, sediment discharge for the Sacramento River Basin increased the most with increased storm magnitude and frequency and decreased the most with increases in air temperature, regardless of changes in precipitation. The model will be used to develop projections of potential hydrologic and sediment trends to the Bay-Delta in response to potential future climate scenarios, which will help assess the hydrological and ecological health of the Bay-Delta into the next century.

  14. Characterizing and simulating sediment loads and transport in the lower part of the San Antonio River Basin

    USGS Publications Warehouse

    Banta, J. Ryan; Ockerman, Darwin J.; Crow, Cassi; Opsahl, Stephen P.

    2015-01-01

    This extended abstract is based on the U.S. Geological Survey Scientific Investigations Reports by Crow et al. (2013) and Banta and Ockerman (2014). Suspended sediment in rivers and streams can play an important role in ecological health of rivers and estuaries and consequently is an important issue for water-resource managers. The quantity and type of suspended sediment can affect the biological communities (Wood and Armitage, 1997), the concentration and movement of natural constituents and anthropogenic contaminants (Moran and others, 2012), and the amount of sediment deposition in coastal environments (Milliman and Meade, 1983). To better understand suspended-sediment characteristics in the San Antonio River Basin, the U.S. Geological Survey (USGS), in cooperation with the San Antonio River Authority and Texas Water Development Board, conducted a two-phase study to (1) collect and analyze sediment data to characterize sediment conditions in the San Antonio River downstream of San Antonio, Texas, and (2) develop and calibrate a watershed model to simulate hydrologic conditions and suspended-sediment loads for four watersheds in the San Antonio River Basin, downstream from San Antonio, Texas.

  15. Suspended sediment and carbonate transport in the Yukon River Basin, Alaska: Fluxes and potential future responses to climate change

    USGS Publications Warehouse

    Dornblaser, M.M.; Striegl, R.G.

    2009-01-01

    Loads and yields of suspended sediment and carbonate were measured and modeled at three locations on the Yukon, Tanana, and Porcupine Rivers in Alaska during water years 2001-2005 (1 October 2000 to 30 September 2005). Annual export of suspended sediment and carbonate upstream from the Yukon Delta averaged 68 Mt a-1 and 387 Gg a-1, respectively, with 50% of the suspended sediment load originating in the Tanana River Basin and 88% of the carbonate load originating in the White River Basin. About half the annual suspended sediment export occurred during spring, and half occurred during summer-autumn, with very little export in winter. On average, a minimum of 11 Mt a-1 of suspended sediment is deposited in floodplains between Eagle, Alaska, and Pilot Station, Alaska, on an annual basis, mostly in the Yukon Flats. There is about a 27% loss in the carbonate load between Eagle and Yukon River near Stevens Village, with an additional loss of about 29% between Stevens Village and Pilot Station, owing to a combination of deposition and dissolution. Comparison of current and historical suspended sediment loads for Tanana River suggests a possible link between suspended sediment yield and the Pacific decadal oscillation.

  16. Inter-comparison of the potentially active prokaryotic communities in the halocline sediments of Mediterranean deep-sea hypersaline basins.

    PubMed

    Kormas, Konstantinos A; Pachiadaki, Maria G; Karayanni, Hera; Leadbetter, Edward R; Bernhard, Joan M; Edgcomb, Virginia P

    2015-09-01

    The sediment microbiota of the Mediterranean deep-sea anoxic hypersaline basins (DHABs) are understudied relative to communities in the brines and halocline waters. In this study, the active fraction of the prokaryotic community in the halocline sediments of L' Atalante, Urania, and Discovery DHABs was investigated based on extracted total RNA and 454 pyrosequencing of the 16S rRNA gene. Bacterial and archaeal communities were different in the sediments underlying the halocline waters of the three habitats, reflecting the unique chemical settings of each basin. The relative abundance of unique operational taxonomic units (OTUs) was also different between deep-sea control sediments and sediments underlying DHAB haloclines, suggesting adaptation to the steep DHAB chemical gradients. Only a few OTUs were affiliated to known bacterial halophilic and/or anaerobic groups. Many OTUs, including some of the dominant ones, were related to aerobic taxa. Archaea were detected only in few halocline samples, with lower OTU richness relative to Bacteria, and were dominated by taxa associated with methane cycling. This study suggests that, while metabolically active prokaryotic communities appear to be present in sediments underlying the three DHABs investigated, their diversity and activity are likely to be more reduced in sediments underlying the brines. PMID:26174531

  17. Estimating the effects of sill intrusion on sediments in Guaymas Basin, Gulf of California based on seismic velocity

    NASA Astrophysics Data System (ADS)

    Feng, H. S.; Lizarralde, D.

    2012-12-01

    We present measurements of the change in sedimentary seismic velocity due to intrusion of magmatic sills into the sediments of Guaymas Basin, a young, sedimented spreading center in the Gulf of California. In Guaymas Basin, igneous sills, on average 1 km in width, intrude sediments at depths of hundreds of meters below the seafloor. Sediments at these depths are young and, where they are not close to a recently intruded sill, have experienced little diagentic changes. However, multichannel seismic (MCS) images show that these shallow sediments are structurally disrupted immediately above intruded sills. This disruption probably indicates some degree of thermogenic alteration due to the intruded sills, because Deep Sea Drilling Project (DSDP) Leg 64 cores recovered from the axial trough of Guaymas Basin show that sediments above intruded sills are typically highly altered, with alteration including substantial porosity reduction and carbon loss. Shallow sill emplacement appears to be widespread throughout Guaymas Basin, and because the sediments are rich in organic carbon, it is possible that carbon released from the sediments into the ocean via this mechanism is an important component of the carbon budget of this basin. If widespread shallow sill intrusion is common to other young rifts and backarc spreading centers, then this mechanism may result in a globally important flux of carbon into the ocean. In addition, it has been suggested that carbon release due to sill intrusion associated with large magmatic events, such as the formation of the Siberian traps and the North Atlantic Tertiary igneous province, has led to global warming events. The degree of alteration and carbon release resulting from widespread heating of organic-rich sediments is poorly known, however. Our results attempt to remotely quantify the degree of sediment alteration due to sill intrusion based on changes in sediment seismic velocity. The MCS images from Guaymas Basin enable us to identify

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

    SciTech Connect

    Jahnke, R.A.

    1990-06-11

    Sediment microbial community biomass and activity in Santa Monica Basin, a nearshore basin in the California Continental Borderland, were examined in October 1985, 1986 and 1987, May 1986, April 1987 and January 1990. Millimeter-scale ATP profiles and incubation of intact cores with {sup 3}H-adenine indicated a high-biomass interface microbial population in the low-oxygen central basin, which was absent in samples from the basin slope sediments. A majority of microbial activity and organic matter mineralization occurred in the top cm of sediment. Comparison of measured ATP and total organic carbon profiles suggest that the C:ATP ratio (wt:wt) ranges between 47:1 and 77:1 in central basin interfacial populations, substantially lower than reported for other aquatic environments. Carbon production estimated from DNA synthesis measurements via {sup 3}H-adenine incorporation was compared with TCO{sub 2} fluxes measured by in situ benthic chamber experiments. Within the uncertainty of the C:ATP ratio, an overall microbial carbon assimilation efficiency of 75--90% was indicated. The low C:ATP ratios and high carbon assimilation efficiencies significantly affect estimates of microbial growth and respiration and are substantially different than those often assumed in the literature. These results suggest that without independent knowledge of these ratios, the uncertainty in tracer-derived microbial growth and respiration rates may be larger than previously reported. 66 refs., 8 figs., 3 tabs.

  19. Preliminary analysis of water discharge and suspended sediment data from the Columbia River Basin: shifting rating curves and diminishing sediment loads

    NASA Astrophysics Data System (ADS)

    MacGregor, K. R.; Gelfenbaum, G.; Rubin, D.

    2003-12-01

    Significant erosion along the coastlines of southwestern Washington in the last decade has motivated increased studies of sediment sources, sinks, and transport dynamics in the region. A key question is whether a reduction in sediment supply is responsible for the recent shift from a depositional regime. Because the Columbia River is the major fluvial system in the littoral cell, it is important to quantify sediment flux from the Columbia River to the coastal environment. We examine historical records of water discharge and suspended sediment transport along the Columbia main stem and in three subbasins in an attempt to quantify changes in total sediment transport and total load, and examine possible shifts in sediment sources over time. Suspended sediment data from the main stem near Vancouver, WA demonstrate a 3 to 5 fold downward shift in the rating curve in the last 90 years. The same trend is visible in data from the Snake River, with a decrease of almost an order of magnitude in sediment transport since the 1950's. Grain size data from the Kootenai River show a clear fining trend in the suspended load. The John Day River is the only long-term record we examined with no change in the rating curve over time; it is also the largest undammed river in the basin. Calculations of sediment load in the main stem were made using actual water discharge, estimated discharge (assuming no dams), and calculated `virgin' flow (Naik and Jay, in review). Preliminary results suggest that changes in the hydrograph (assuming a uniform rating curve) would diminish sediment transport to the coast by up to 20% over the last century; changes in the rating curve are responsible for at least that change, possibly more.

  20. Simulation studies of flow and sediment transport using a mathematical model, Atchafalaya River Basin, Louisiana

    USGS Publications Warehouse

    Jennings, M.E.; Land, L.F.

    1977-01-01

    Simulation studies were made of flow and sediment transport for the Atchafalaya River basin, Louisiana using a mathematical model calibrated and supplied by the Hydrologic Engineering Center and the New Orleans District, U.S. Army Corps of Engineers. The study results are based on three, 50-year computer simulations for the following alternatives: (1) no-action alternative, (2) channelization with a center-channel flow area of 80,000 sq ft, and (3) channelization with a center-channel flow area of 100,000 sq ft. Analyses of the simulated data base for depth-frequency, inundated-area, floodway cross-section and water-surface profile relationships were made for 10 flow rates. The analyses indicate a general trend of aggradation in the lower part of the floodway with a consequent trend toward increasing the inundated area, especially at higher flood flows. (Woodard-USGS)

  1. Erodibility of selected soils and estimates of sediment yields in the San Juan Basin, New Mexico

    USGS Publications Warehouse

    Summer, Rebecca M.

    1981-01-01

    Onsite rainfall-simulation experiments were conducted to derive field-erodibility indexes for rangeland soils and soils disturbed by mining in coal fields of northwestern New Mexico. Mean indexes on rangeland soils range from 0 grams (of detached soil) on dune soil to 121 grams on wash-transport zones. Mean field-erodibility-index values of soils disturbed by mining range from 16 to 32 grams; they can be extrapolted to nearby coal fields where future mining is expected. Because field-erodibility-index data allow differentiation of erodibilities across a variable landscape, these indexes were used to adjust values of K, the erodibility factor of the Universal Soil Loss Equation. Estimates of soil loss and sediment yield were then calculated for a small basin following mining. (USGS)

  2. Fluvial-aeolian interactions in sediment routing and sedimentary signal buffering: an example from the Indus Basin and Thar Desert

    USGS Publications Warehouse

    East, Amy E.; Clift, Peter D.; Carter, Andrew; Alizai, Anwar; VanLaningham, Sam

    2015-01-01

    Sediment production and its subsequent preservation in the marine stratigraphic record offshore of large rivers are linked by complex sediment-transfer systems. To interpret the stratigraphic record it is critical to understand how environmental signals transfer from sedimentary source regions to depositional sinks, and in particular to understand the role of buffering in obscuring climatic or tectonic signals. In dryland regions, signal buffering can include sediment cycling through linked fluvial and eolian systems. We investigate sediment-routing connectivity between the Indus River and the Thar Desert, where fluvial and eolian systems exchanged sediment over large spatial scales (hundreds of kilometers). Summer monsoon winds recycle sediment from the lower Indus River and delta northeastward, i.e., downwind and upstream, into the desert. Far-field eolian recycling of Indus sediment is important enough to control sediment provenance at the downwind end of the desert substantially, although the proportion of Indus sediment of various ages varies regionally within the desert; dune sands in the northwestern Thar Desert resemble the Late Holocene–Recent Indus delta, requiring short transport and reworking times. On smaller spatial scales (1–10 m) along fluvial channels in the northern Thar Desert, there is also stratigraphic evidence of fluvial and eolian sediment reworking from local rivers. In terms of sediment volume, we estimate that the Thar Desert could be a more substantial sedimentary store than all other known buffer regions in the Indus basin combined. Thus, since the mid-Holocene, when the desert expanded as the summer monsoon rainfall decreased, fluvial-eolian recycling has been an important but little recognized process buffering sediment flux to the ocean. Similar fluvial-eolian connectivity likely also affects sediment routing and signal transfer in other dryland regions globally.

  3. The grain size of fluvial and hillslope sediments across an erosion gradient in the Feather River Basin, California

    NASA Astrophysics Data System (ADS)

    Mudd, Simon; Attal, Mikael; Hurst, Martin; Yoo, Kyungsoo; Weinman, Beth; Naylor, Mark

    2016-04-01

    Grain size in hillslope sediments is conditioned by erosion rates and processes, and these sediments are then delivered to channels. How the channels respond to and modify these characteristics dictate whether rivers aggrade or erode their substrate. We investigate how the grain size of hillslope and fluvial sediments respond to an erosion gradient within the Feather River basin in northern California. Studied basins are underlain exclusively by tonalite lithology. Erosion rates vary over an order of magnitude, from >250 mm ka-1 in the Feather River canyon to <15 mm ka-1 on an adjacent low-relief plateau. Hillslope particle size increases with increasing steepness, a proxy for erosion rate. We hypothesise that, in our soil samples, the measured 10-fold increase in D50 and doubling of the amount of fragments larger than 1 mm when slope increases from 0.38 to 0.83 m m-1 is due to a decrease in the residence time of rock fragments, causing particles to be exposed for shorter periods of time to processes that can reduce grain size. For slopes in excess of 0.7 m m-1, landslides and scree cones supply much coarser sediment to rivers, with D50 and D84 more than one order of magnitude larger than in soils. In the tributary basins of the Feather River, a prominent knickpoint separates the rapidly eroding canyon from the slowly eroding plateau. Downstream of the break in slope, fluvial sediment grain size increases, due to an increase in flow competence (mostly driven by channel steepening) as well as a change in sediment source and in sediment dynamics: on the plateau, rivers transport easily mobilized fine-grained sediment derived exclusively from soils. In the Feather River Canyon, mass wasting processes supply a wide range of grain sizes that rivers entrain selectively, depending on the competence of their flow.

  4. The grain size of fluvial and hillslope sediments across an erosion gradient in the Feather River Basin, California

    NASA Astrophysics Data System (ADS)

    Mudd, Simon; Attal, Mikael; Hurst, Martin; Yoo, Kyungsoo; Weinman, Beth; Naylor, Mark

    2016-04-01

    Grain size in hillslope sediments is conditioned by erosion rates and processes, and these sediments are then delivered to channels. How the channels respond to and modify these characteristics dictate whether rivers aggrade or erode their substrate. We investigate how the grain size of hillslope and fluvial sediments respond to an erosion gradient within the Feather River basin in northern California. Studied basins are underlain exclusively by tonalite lithology. Erosion rates vary over an order of magnitude, from >250 mm ka‑1 in the Feather River canyon to <15 mm ka‑1 on an adjacent low-relief plateau. Hillslope particle size increases with increasing steepness, a proxy for erosion rate. We hypothesise that, in our soil samples, the measured 10-fold increase in D50 and doubling of the amount of fragments larger than 1 mm when slope increases from 0.38 to 0.83 m m‑1 is due to a decrease in the residence time of rock fragments, causing particles to be exposed for shorter periods of time to processes that can reduce grain size. For slopes in excess of 0.7 m m‑1, landslides and scree cones supply much coarser sediment to rivers, with D50 and D84 more than one order of magnitude larger than in soils. In the tributary basins of the Feather River, a prominent knickpoint separates the rapidly eroding canyon from the slowly eroding plateau. Downstream of the break in slope, fluvial sediment grain size increases, due to an increase in flow competence (mostly driven by channel steepening) as well as a change in sediment source and in sediment dynamics: on the plateau, rivers transport easily mobilized fine-grained sediment derived exclusively from soils. In the Feather River Canyon, mass wasting processes supply a wide range of grain sizes that rivers entrain selectively, depending on the competence of their flow.

  5. The Role of Source Material in Basin Sedimentation, as Illustrated within Eureka Valley, Death Valley National Park, CA.

    NASA Astrophysics Data System (ADS)

    Lawson, M. J.; Yin, A.; Rhodes, E. J.

    2015-12-01

    Steep landscapes are known to provide sediment to sink regions, but often petrological factors can dominate basin sedimentation. Within Eureka Valley, in northwestern Death Valley National Park, normal faulting has exposed a steep cliff face on the western margin of the Last Chance range with four kilometers of vertical relief from the valley floor and an angle of repose of nearly 38 degrees. The cliff face is composed of Cambrian limestone and dolomite, including the Bonanza King, Carrara and Wood Canyon formations. Interacting with local normal faulting, these units preferentially break off the cliff face in coherent blocks, which result in landslide deposits rather than as finer grained material found within the basin. The valley is well known for a large sand dune, which derives its sediment from distal sources to the north, instead of from the adjacent Last Chance Range cliff face. During the Holocene, sediment is sourced primary from the northerly Willow Wash and Cucomungo canyon, a relatively small drainage (less than 80 km2) within the Sylvan Mountains. Within this drainage, the Jurassic quartz monzonite of Beer Creek is heavily fractured due to motion of the Fish Valley Lake - Death Valley fault zone. Thus, the quartz monzonite is more easily eroded than the well-consolidated limestone and dolomite that forms the Last Change Range cliff face. As well, the resultant eroded material is smaller grained, and thus more easily transported than the limestone. Consequently, this work highlights an excellent example of the strong influence that source material can have on basin sedimentation.

  6. Reconstructing the small river basin sediment budget and associated particle-bound contaminants redistribution (Chern River, European Russia)

    NASA Astrophysics Data System (ADS)

    Belyaev, Vladimir; Aseeva, Elena; Golosov, Valentin

    2015-04-01

    Reconstruction of the basin-scale sediment budget and associated particle-bound pollutants redistribution was carried out within the upper part of the Chern River basin (133 km2). It involved application of integrated approach based on use of several independent techniques. The study river basin is located on the border between the Orel and Kursk Regions of the Central European Russia nearby the Mikhailovskiy opencast iron ore mine and processing plant, which are believed to be the main local sources of air-borne pollutants. In addition, the basin was contaminated by radionuclide fallout after the Chernobyl accident in 1986. Combination of geomorphic, geochemical, soil survey and geodetic methods has allowed authors to evaluate dynamics of sediment and contaminants redistribution for the last 50 years (since the beginning of a mining activity) within the upper part of the basin upstream from the reservoir, located in the middle reach of the main valley. Main techniques applied were field description of soil or sediment sections, the 137Cs radioactive tracer (for estimation average soil loss rates from eroding cultivated hillslopes and for reconstruction of accumulation rates and sediment microstratigraphy for deposition locations such as main river floodplain and bottoms of small dry valleys), chemical analysis (content of selected heavy metals and As - both in mobile forms by atomic absorption spectroscopy and total by X-ray fluorescence spectrometry, organic C content, pH), geomorphic and detailed geodetic survey of selected key sections of the Chern River floodplain, calculation of average soil erosion rates for cultivated area of the studied part of the basin by the empirical model. In addition, two detailed bottom sediment cores were taken from the reservoir bottom which intercepts practically all the sediment delivered from the upper part of the basin. Integrating the obtained data, it has been found out that substantial changes of the sediment budget took

  7. Provenance and sediment-dispersal system in tectonically active rapidly evolving foreland basin, Western Interior

    SciTech Connect

    Khandaker, N.I.; Vondra, C.F.

    1989-03-01

    The Upper Cretaceous Frontier Formation, along the mobile edge of the Western Interior foreland basin, is composed mainly of clastic sediments and was deposited during the initial Late Cretaceous transgressive-regressive phases of the Western Interior seaway across Wyoming. The formation contains many persistent bentonite beds and several sandstone packages in its lower part and a thin, lenticular lithic wacke-polymictic conglomerate association at its upper contact (Torchlight Sandstone Member). Abundant granule to cobble-sized clasts of andesite, granite, chert, and quartzite are set in a poorly sorted sand-to-granule grade volcaniclastic matrix. There is a lithologic continuity of this volcaniclastic unit across the Bighorn Mountains into the Powder River basin. A high-energy distributary complex of sizable areal extent is invoked for the deposition of this linear conglomerate facies. Geochemical investigations of the whole-rock andesite clasts and bentonite allowed more precise definition of character, tectonic setting, and evolutionary stages of sedimentary distributive provinces. Bentonites and andesites are strongly enriched in strontium and barium, but only mildly enriched in heavy rare earth elements and high field-strength elements. These analyzed rocks have trace element characteristics similar in a general way to those of typical orogenic volcanics; they show some significant differences in detail. Composition of volcaniclasts and paleocurrent data indicate a proximal sediment source for the extrabasinal detritus within the Frontier Formation. The possibility of a contribution from a Mesozoic volcanic center in the neighborhood of southwestern Montana is strongly favored. The products of this volcanism constitute an assemblage of deep crustal to mantle( ) derived rocks, and their composition record time-integrated enrichment in light over heavy rare earth elements.

  8. Sediment accumulation rates in time and space: Paleogene genetic stratigraphic sequences of the northwestern Gulf of Mexico basin

    NASA Astrophysics Data System (ADS)

    Galloway, William E.; Williams, Thomas A.

    1991-10-01

    The Paleogene fill of the northwestern Gulf of Mexico basin consists of eight genetic stratigraphic, sequences bounded by regional marine flooding surfaces. Calculation of sediment accumulation rates along dip profiles through four subbasins shows that regional changes in accumulation rate—and by inference, rate of sediment supply—of fivefold to tenfold repeatedly occurred over time spans of 1 to 3 m.y. Major sequences record episodes of high supply and accommodation-limited accumulation. Periods of declining and low supply were characterized by short-term over-accommodation and consequent transgressive flooding of the basin margin. Within sequences, depositional rates varied with position relative to the contemporaneous shelf margin, with type of depositional system, and between subbasins. Normal patterns of load-induced basin-margin subsidence and creation of accommodation space were modified by perturbation of the crustal stress regime.

  9. A consistent magnetic polarity stratigraphy of Plio-Pleistocene fluvial sediments from the Heidelberg Basin (Germany)

    NASA Astrophysics Data System (ADS)

    Scheidt, Stephanie; Hambach, Ulrich; Rolf, Christian

    2014-05-01

    Deep drillings in the Heidelberg Basins provide access to one of the thickest and most complete successions of Quaternary and Upper Pliocene continental sediments in Central-Europe [1]. In absence of any comprehensive chronostratigraphic model, these sediments are so far classified by lithological and hydrogeological criteria. Therefore the age of this sequence is still controversially discussed ([1], [2]). In spite of the fact that fluvial sediments are a fundamental challenge for the application of magnetic polarity stratigraphy we performed a thorough study on four drilling cores (from Heidelberg, Ludwigshafen and nearby Viernheim). Here, we present the results from the analyses of these cores, which yield to a consistent chronostratigraphic framework. The components of natural remanent magnetisation (NRM) were separated by alternating field and thermal demagnetisation techniques and the characteristic remanent magnetisations (ChRM) were isolated by principle component analysis [3]. Due to the coring technique solely inclination data of the ChRM is used for the determination of the magnetic polarity stratigraphy. Rock magnetic proxies were applied to identify the carriers of the remanent magnetisation. The investigations prove the NRM as a stable, largely primary magnetisation acquired shortly after deposition (PDRM). The Matuyama-Gauss boundary is clearly defined by a polarity change in each core, as suggested in previous work [4]. These findings are in good agreement with the biostratigraphic definition of the base of the Quaternary ([5], [6], [7]). The Brunhes-Matuyama boundary could be identified in core Heidelberg UniNord 1 and 2 only. Consequently, the position of the Jaramillo and Olduvai subchron can be inferred from the lithostratigraphy and the development of fluvial facies architecture in the Rhine system. The continuation of the magnetic polarity stratigraphy into the Gilbert chron (Upper Pliocene) allows alternative correlation schemes for the cores

  10. Zinc, cadmium, and copper mobility and accumulation in reeds (Phragmites australis) in urban sediments from two stormwater infiltration basins

    NASA Astrophysics Data System (ADS)

    Bedell, J.-P.; Saulais, S.; Delolme, C.

    2012-04-01

    Infiltration basins are stormwater management techniques that are widely used to reduce stormwater volume. The settling of stormwater particles leads to a contaminated sediment layer at the basin surface. Phragmites australis used in constructed wetlands are widely present in infiltration basins. Such plant can play a role on the fate of heavy metals either directly by their uptake or indirectly by modification of physico-chemical characteristics of the sediment. The aim of this study is to assess Zn, Cd and Cu potential mobility and their bioaccumulation by reeds during plant's growth in urban sediments offering two different geochemical contexts. Methodology is based on the monitoring (in june, august and december) of physico-chemical characteristics of sediment deposit in two basins. These basins, "Minerve" and "Grézieu", located on both sides of Lyon city are characteristic of two different geochemical context. "Minerve" is in the east and "Grézieu" in the west part. The geology of the eastern part of Lyon is characterized by carbonated fluvio-glacial deposits. In the western part, the subsoil is mainly composed of gneiss and granit. Moreover, 20 cm of gravel and a sand layer were initially added at the surface of the "Grézieu" basin. In "Minerve", a clay material was initially added and a filter trench was built along the basin to allow water infiltration. We characterized the sediment deposit by the identification of their geochemical characteristics (Zn, Cu, Cd, total content, pH, CEC, C/N, carbonates and major elements contents …). Then we studied the potential mobility of the three metals by single chemical extraction (CaCl2 for the exchangeable phase, acetate buffer for the acido-soluble phase and diethylenetriamine-pentaacetic acid (DTPA) for the fraction associated to the organic matter). The accumulation of Zn, Cd and Cu in aerial parts and roots of the reeds was also measured. The results show clearly that "Grézieu" sediment is more enriched in

  11. Effects of coal mining on the water quality and sedimentation of Lake Tuscaloosa and selected tributaries, North River basin, Alabama

    USGS Publications Warehouse

    Cole, E.F.

    1985-01-01

    Lake Tuscaloosa, a reservoir on North River, is the primary source of water supply for the city of Tuscaloosa, Alabama, and surrounding areas. Between October 1982 and September 1983, 14 sites in the North River basin were sampled to determine if surface coal mining has impacted the quality of water in the lake and selected tributaries. Water draining mined basins showed increases in specific conductance, sulfate concentrations , and dissolved and total recoverable iron and manganese concentrations after mining started in 1975. Although water in the reservoir has become more mineralized with only an estimated 5 percent of the basin mined, total dissolved solids concentrations are still very low, ranging from 28 to 35 milligrams per liter at the dam. The quality of water at most sites was, except for pH, iron, and manganese, within secondary drinking water standards. The pH of water from streams draining either mined or unmined basins was generally less than 6.5. Sedimentation has occurred at most measured lake cross sections since impoundment. However, natural factors such as steep overland and channel slopes, may cause more sedimentation in the lake from unmined basins than from coal mining in a different basin. (USGS)

  12. Allogenic processes, sediment flux, and Carboniferous stratigraphy in the Appalachian basin

    SciTech Connect

    Cecil, C.B.; Dulong, F.T.; Edgar, N.T. )

    1992-01-01

    The origin of Carboniferous strata in the central Appalachian basin is being evaluated as a function of paleoclimatic, eustatic, and tectonic processes. Of these processes, paleoclimate has, in the past, received the least attention but appears to be of primary importance as a control on stratigraphy. For example, Upper Mississippian strata include both marine carbonates and marine dark gray to black shales. The marine carbonate units are underlain and overlain by paleosols that contain calcic peds, pseudomorphs of gypsum, and rhizoconcretions with vertical root structures suggesting low soil moisture. The marine limestone generally is in sharp contact with an underlying paleosol. The lithostratigraphy of such a sequence is consistent with a transgressive-regressive cycle under relatively dry (semiarid) climatic conditions, which limits siliciclastic influx. In contrast, the marine gray and black shales are bounded by leached paleosols containing horizontal rhizomorphs and coal beds suggestive of wet soil conditions. Terrestrial organic matter in marine shales indicate relatively high terrestrial organic productivity, and the shale units are in gradational contact with underling strata. The lithostratigraphy of the marine shale sequences is consistent with deposition under relatively wet climatic regimes (probably seasonal and subhumid), which increased siliciclastic and terrestrial organic matter input. Relatively short-term climate cycles were a primary control on sediment flux within Carboniferous deposystems in the Appalachian basin. Long-term climate change also occurred as eastern North America moved from relatively dry latitudes of the southern hemisphere through the tropical rainy belt into drier latitudes of the northern hemisphere. Long-term tectonic change provided accommodation space. Such controls can readily be observed throughout Carboniferous strata in the Appalachian basin.

  13. Sediment infill within rift basins: Facies distribution and effects of deformation: Examples from the Kenya and Tanganyika Rifts, East Africa

    SciTech Connect

    Tiercelin, J.J.; Lezzar, K.E. ); Richert, J.P. )

    1994-07-01

    Oil is known from lacustrine basins of the east African rift. The geology of such basins is complex and different depending on location in the eastern and western branches. The western branch has little volcanism, leading to long-lived basins, such as Lake Tanganyika, whereas a large quantity of volcanics results in the eastern branch characterized by ephemeral basins, as the Baringo-Bogoria basin in Kenya. The Baringo-Bogoria basin is a north-south half graben formed in the middle Pleistocene and presently occupied by the hypersaline Lake Bogoria and the freshwater Lake Baringo. Lake Bogoria is fed by hot springs and ephemeral streams controlled by grid faults bounding the basin to the west. The sedimentary fill is formed by cycles of organic oozes having a good petroleum potential and evaporites. On the other hand, and as a consequence of the grid faults, Lake Baringo is fed by permanent streams bringing into the basin large quantities of terrigenous sediments. Lake Tanganyika is a meromictic lake 1470 m deep and 700 km long, of middle Miocene age. It is subdivided into seven asymmetric half grabens separated by transverse ridges. The sedimentary fill is thick and formed by organic oozes having a very good petroleum potential. In contrast to Bogoria, the lateral distribution of organic matter is characterized by considerable heterogeneity due to the existence of structural blocks or to redepositional processes.

  14. Channel erosion and sediment transport in Pheasant Branch basin near Middleton, Wisconsin; a preliminary report

    USGS Publications Warehouse

    Grant, R. Stephen; Goddard, Gerald

    1980-01-01

    The purpose of this 5-year study is to (1) evaluate the sediment transport, streamflow characteristics, and stream-channel morphology, (2) relate the above to land-use practices; and (3) evaluate the effect that changes in land-use practices will have on Pheasant Branch basin near Middleton, Wis. This report presents findings of sediment transport, streamflow characteristics, and stream-channel morphology from the first year of the study and documents historical erosion. The study is being conducted by the U.S. Geological Survey in cooperation with the city of Middleton and the Wisconsin Geological and Natural History Survey. Pheasant Branch, a tributary to Lake Mendota, drains 23.1 square miles of glacial drift. Channel erosion is severe within Middleton, requiring extensive use of erosion-control structures. Occasionally, channel dredging near the mouth and into Lake Mendota is required for boating. Comparison of stream-channel surveys of 1971 and 1977 shows the lowest part of the channel lowered 3 to 4 feet at some sites in the urban reach from U.S. Highway 12 downstream to Century Avenue. Downstream from Century Avenue, channel width increased from about 35 to 48 feet and channel cross-section area increased about 86 percent. A survey of Pheasant Branch in 1971 provided data for quantification of stream-channel changes since that time. Six erosion-control structures previously installed appear to have had some benefit in controlling head cutting in the channel. (USGS).

  15. Geochemical characterization of streambed sediment in the upper Illinois River basin

    USGS Publications Warehouse

    Colman, J.A.; Sanzolone, R.F.

    1992-01-01

    Geochemistry of fine-fraction streambed sediments collected from the upper Illinois River basin was surveyed in the fall of 1987 as part of the U.S. Geological Survey National Water-Quality Assessment pilot projects. The survey included 567 samples analyzed for 46 elements. Three distinctive distribution patterns were found for seven U.S. Environmental Protection Agency priority pollutants surveyed, as well as for boron and phosphorus: (1) enrichment of elements in the Chicago urban area and in streams draining the urban area relative to rural areas, (2) enrichment in main stems relative to tributaries, and (3) enrichment in low-order streams at high-population-density sites relative to low-population-density sites. Significant differences in background concentrations, as measured by samples from low-order streams, were observed among five subbasins in the study area. Uncertain geochemical correspondence between low-order, background sites and high-order, generally metal enriched sites prevented determination of background levels that would be appropriate for high-order sites. The within-sample ratio of enriched elements was variable within the Chicago area but was constant in the Illinois River downstream from Chicago. Element ratios imply a composite fine-fraction sediment in the Illinois River of 35-40 percent Des Plaines River origin and 60-65 percent Kankakee River origin.

  16. Marine silicate weathering in the anoxic sediment of the Ulleung Basin: Evidence and consequences

    NASA Astrophysics Data System (ADS)

    Kim, Ji-Hoon; Torres, Marta E.; Haley, Brian A.; Ryu, Jong-Sik; Park, Myong-Ho; Hong, Wei-Li; Choi, Jiyoung

    2016-08-01

    Marine silicate weathering (MSiW) in anoxic sediments has been recently shown to be a significant sink for CO2 generated by methanogenesis. Independently, the roles of clay dehydration (illitization) in producing water and driving upward fluid advection have been well established in deep marine sediments, but to date the K+ source required for the reaction has not been established. Here we present chemical and strontium isotope properties of pore fluids from seven cores in the Ulleung Basin, which show radiogenic 87Sr/86Sr values (up to ˜0.71045), very high alkalinity values (maximum ˜130 mM), and enrichment in H4SiO4, Na+, K+, and Mg2+, consistent with MSiW. This reaction consumes CO2, generates alkalinity, and acts as a K+ source for illitization; water released from MSiW-supported illitization drives upward fluid flow. Our results highlight the importance of MSiW along continental margins and its underappreciated role in carbon cycling, silicate diagenesis, and hydrogeology of marine systems.

  17. Impact of discharge and sediment flux on basin margin architecture: an experimental approach.

    NASA Astrophysics Data System (ADS)

    van den Berg van Saparoea, A. P. H.; Postma, G.

    2003-04-01

    In most cases it is very difficult to evaluate the stratigraphic record in terms of causality. Important parameters in fluvial-deltaic settings are relative sea level and the ratio of discharge (Q) and solid load (Qs). We use analogue modelling for unravelling the role of each in strata formation over long time spans. The changes in the modelled system are monitored by means of digital elevation maps (DEM's) of the surface, and are calibrated against the last glacial cycle stratigraphic record of the Colorado (Texas, USA) fluvial-delta-shelf system. The influence of relative sea level at constant Q/Qs ratio has been investigated in a previous series of experiments [1]. In the experiments described here Q/Qs ratio is varied, while the rate of change in relative sea level is kept constant. Our preliminary results indicate that the efficiency of sediment transport increases with higher Q/Qs ratios. A system with high Q/Qs ratio is predominantly progradational, while a system with a low Q/Qs ratio shows progradation and aggradation over the entire shelf. Secondly there is a clear relation between the Q/Qs ratio and the cone shaped distribution of sediment over the shelf. The lower the Q/Qs ratio, the higher the spreading angle due to increase in avulsion frequency in the apex of the delta with increasing sediment load. Thirdly, the amount of incision into the original shelf material depends both on the ability of the system to erode (the discharge) and the amount of sediment available for deposition. As a consequence, at low Q/Qs ratios there is a minimum of shelf incision and cannibalisation of shelf stratigraphy, while sediments deposited in the falling stage systems tract are continuously reworked and redeposited. Hence, the lowstand fans contain high amounts of fluvial material transported during the sea-level fall. This is in contrast with high Q/Qs ratios that lead to shelf incision and increased headward erosion rates in the fluvial valleys. The connection time

  18. Mercury and methylmercury in water and sediment of the Sacramento River Basin, California

    USGS Publications Warehouse

    Domagalski, J.

    2001-01-01

    Mercury (Hg) and methylmercury (CH3Hg+) concentrations in streambed sediment and water were determined at 27 locations throughout the Sacramento River Basin, CA. Mercury in sediment was elevated at locations downstream of either Hg mining or Au mining activities where Hg was used in the recovery of Au. Methylmercury in sediment was highest (2.84 ng/g) at a location with the greatest wetland land cover, in spite of lower total Hg at that site relative to other river sites. Mercury in unfiltered water was measured at 4 locations on the Sacramento River and at tributaries draining the mining regions, as well as agricultural regions. The highest levels of Hg in unfiltered water (2248 ng/l) were measured at a site downstream of a historic Hg mining area, and the highest levels at all sites were measured in samples collected during high streamflow when the levels of suspended sediment were also elevated. Mercury in unfiltered water exceeded the current federal and state recommended criterion for protection of aquatic life (50 ng/l as total Hg in unfiltered water) only during high streamflow conditions. The highest loading of Hg to the San Francisco Bay system was attributed to sources within the Cache Creek watershed, which are downstream of historic Hg mines, and to an unknown source or sources to the mainstem of the Sacramento River upstream of historic Au mining regions. That unknown source is possibly associated with a volcanic deposit. Methylmercury concentrations also were dependent on season and hydrologic conditions. The highest levels (1.98 ng/l) in the Sacramento River, during the period of study, were measured during a major flood event. The reactivity of Hg in unfiltered water was assessed by measuring the amount available for reaction by a strong reducing agent. Although most Hg was found to be nonreactive, the highest reactivity (7.8% of the total Hg in water) was measured in the sample collected from the same site with high CH3Hg+ in sediment, and during

  19. Patterns and processes of fluvial discontinuity and sediment residence times on the lower Macquarie River, Murray-Darling Basin, Australia

    NASA Astrophysics Data System (ADS)

    Larkin, Zacchary; Ralph, Timothy; Hesse, Paul

    2014-05-01

    The supply, transport and deposition of fine-grained sediment are important factors determining the morphology of lowland rivers that experience channel breakdown and have wetlands on their lower reaches. Sediment supply and residence time determine whether reaches accumulate sediment (wetland areas) or erode sediment (channelised areas). This research investigated how processes of sedimentation and erosion drive channel breakdown and reformation in the Macquarie Marshes, a large anastomosing wetland system in the Murray-Darling Basin, Australia. Channel breakdown is attributed to a dominance of in-stream sedimentation that leads to a point where single-thread river channels cannot be maintained and so avulsion and floodout processes create smaller distributary channels and wetlands. Avulsions may reconnect channels, changing the sediment supply regime in those particular channels. Channel reformation occurs on the trunk stream where the floodplain gradient steepens enough to allow convergence of small tributaries, locally increasing stream power (and erosive energy in channels). As each river reach reforms following channel breakdown, the channel is smaller, shallower and straighter than the previous reach. One reach in this system recently (in the 1970s) became connected with a parallel channel through avulsion and has morphological characteristics that indicate a significant change in flow and sediment supply. In a pilot study using uranium-series disequilibrium methods and OSL dating, a sediment residence time of 58 +/- 2 ka was determined for sediment in the base of the active channel and a sediment residence time of 153 +/- 5 ka was determined for sediment buried in an adjacent meander that was cut off from the main channel 1,000 years ago. The apparent dramatic decrease in sediment residence time to this active channel poses an interesting question about the role of relatively new channels in transporting and depositing sediment more rapidly than the

  20. A Rouse-based method to integrate the chemical composition of river sediments: Application to the Ganga basin

    NASA Astrophysics Data System (ADS)

    Lupker, Maarten; France-Lanord, Christian; Lavé, JéRôMe; Bouchez, Julien; Galy, Valier; MéTivier, FrançOis; Gaillardet, JéRôMe; Lartiges, Bruno; Mugnier, Jean-Louis

    2011-12-01

    The Ganga River is one of the main conveyors of sediments produced by Himalayan erosion. Determining the flux of elements transported through the system is essential to understand the dynamics of the basin. This is hampered by the chemical heterogeneity of sediments observed both in the water column and under variable hydrodynamic conditions. Using Acoustic Doppler Current Profiler (ADCP) acquisitions with sediment depth profile sampling of the Ganga in Bangladesh we build a simple model to derive the annual flux and grain size distributions of the sediments. The model shows that ca. 390 (±30) Mt of sediments are transported on average each year through the Ganga at Haring Bridge (Bangladesh). Modeled average sediment grain size parameters D50 and D84 are 27 (±4) and 123 (±9) μm, respectively. Grain size parameters are used to infer average chemical compositions of the sediments owing to a strong grain size chemical composition relation. The integrated sediment flux is characterized by low Al/Si and Fe/Si ratios that are close to those inferred for the Himalayan crust. This implies that only limited sequestration occurs in the Gangetic floodplain. The stored sediment flux is estimated to c.a. 10% of the initial Himalayan sediment flux by geochemical mass balance. The associated, globally averaged sedimentation rates in the floodplain are found to be ca. 0.08 mm/yr and yield average Himalayan erosion rate of ca. 0.9 mm/yr. This study stresses the need to carefully address the average composition of river sediments before solving large-scale geochemical budgets.

  1. Sediment delivery ratio of single flood events and the influencing factors in a headwater basin of the Chinese Loess Plateau.

    PubMed

    Zheng, Mingguo; Liao, Yishan; He, Jijun

    2014-01-01

    Little is known about the sediment delivery of single flood events although it has been well known that the sediment delivery ratio at the inter-annual time scale is close to 1 in the Chinese Loess Plateau. This study examined the sediment delivery of single flood events and the influencing factors in a headwater basin of the Loess Plateau, where hyperconcentrated flows are dominant. Data observed from plot to subwatershed over the period from 1959 to 1969 were presented. Sediment delivery ratio of a single event (SDRe) was calculated as the ratio of sediment output from the subwatershed to sediment input into the channel. It was found that SDRe varies greatly for small events (runoff depth <5 mm or rainfall depth <30 mm) and remains fairly constant (approximately between 1.1 and 1.3) for large events (runoff depth >5 mm or rainfall depth >30 mm). We examined 11 factors of rainfall (rainfall amount, rainfall intensity, rainfall kinetic energy, rainfall erosivity and rainfall duration), flood (area-specific sediment yield, runoff depth, peak flow discharge, peak sediment concentration and flood duration) and antecedent land surface (antecedent precipitation) in relation to SDRe. Only the peak sediment concentration significantly correlates with SDRe. Contrary to popular belief, channel scour tends to occur in cases of higher peak sediment concentrations. Because small events also have chances to attain a high sediment concentration, many small events (rainfall depth <20 mm) are characterized by channel scour with an SDRe larger than 1. Such observations can be related to hyperconcentrated flows, which behave quite differently from normal stream flows. Our finding that large events have a nearly constant SDRe is useful for sediment yield predictions in the Loess Plateau and other regions where hyperconcentrated flows are well developed.

  2. Sedimentation and chemical quality of surface water in the Heart River drainage basin, North Dakota

    USGS Publications Warehouse

    Maderak, Marion L.

    1966-01-01

    The Heart River drainage basin of .southwestern North Dakota comprises an area of 3,365 square miles and lies within the Missouri Plateau of the Great Plains province. Streamflow of the Heart River and its tributaries during 1949-58 was directly proportional to .the drainage area. After the construction of Heart Butte Dam in 1949 and Dickinson Dam in 1950, the mean annual streamflow near Mandan was decreased an estimated 10 percent by irrigation, evaporation from the two reservoirs, and municipal use. Processes that contribute sediment to the Heart River are mass wasting, advancement of valley heads, and sheet, lateral stream, and gully erosion. In general, glacial deposits, terraces, and bars of Quaternary age are sources of sand and larger sediment, and the rocks of Tertiary age are sources of clay, silt. and sand. The average annual suspended-sediment discharges near Mandan were estimated to be 1,300,000 tons for 1945-49 and 710,000 tons for 1970-58. The percentage composition of ions in water of the Heart River, based on average concentrations in equivalents per million for selected ranges of streamflow, changes with flow and from station to station. During extremely low flows the water contains a large percentage of sodium and about equal percentages of bicarbonate and .sulfate, and during extremely high flows the water contains a large percentage of calcium plus magnesium and bicarbonate. The concentrations, in parts per million, of most of the ions vary inversely with flow. The water in the reservoirs--Edward Arthur Patterson Lake and Lake Tschida--during normal or above-normal runoff is of suitable quality for public use. Generally, because of medium or high salinity hazards, the successful long-term use of Heart River water for irrigation will depend on a moderate amount of leaching, ,adequate drainage, ,and the growing of crops that have moderate or good salt tolerance.

  3. Pesticides in surface water, sediment, and rainfall of the northeastern Pantanal basin, Brazil.

    PubMed

    Laabs, Volker; Amelung, Wulf; Pinto, Alicio A; Wantzen, Matthias; da Silva, Carolina J; Zech, Wolfgang

    2002-01-01

    Within the last 25 years an intensive agriculture has developed in the highland regions of Mato Grosso state (Brazil), which involves frequent pesticide use in highly mechanized cash-crop cultures. To provide information on pesticide distribution and dynamics in the northeastern Pantanal basin (located in southern Mato Grosso), we monitored 29 pesticides and 3 metabolites in surface water, sediment, and rainwater of the study area during the main application season. In environmental samples, 19 pesticides and 3 metabolites were detected in measurable quantities, resulting in at least one pesticide detection in 68% of surface water samples (n = 139), 62% of sediment samples (n = 26), and 87% of rainwater samples (n = 91). Surface water samples were most frequently contaminated by endosulfan compounds (alpha-, beta-, -sulfate), ametryn, metolachlor, and metribuzin, although in low (< 0.1 microgram L-1) concentrations. Sediment samples exhibited concentrations up to 4.5 micrograms kg-1 of p,p'-DDT, p,p'-DDE, endosulfan-sulfate, beta-endosulfan, and ametryn. In contrast, rainwater was polluted with substantial amounts of endosulfan, alachlor, metolachlor, trifluralin, monocrotofos, and profenofos (maximum concentrations = 0.3 to 2.3 micrograms L-1) in the highlands. Lowland rainwater samples taken 75 km from the next application area contained 5- to 10-fold lower mean pesticide concentration than in the highlands. Cumulative deposition rates of the pesticide sum within the study period ranged from 423 micrograms m-2 in the highlands to 14 micrograms m-2 in the lowlands. The atmospheric input of pesticides to ecosystems seemed to be of higher relevance in the tropical study area than known from temperate regions. PMID:12371181

  4. Geotechnical and sedimentological investigations of deep-sea sediments from a manganese nodule field of the Peru Basin

    NASA Astrophysics Data System (ADS)

    Grupe, Bernd; Becker, Hermann J.; Oebius, Horst U.

    Deep-sea mining of manganese nodules will significantly modify the surface layer of deep sea. Surface sediments are mechanically disturbed, and a cloud of sediment particles suspended and re-deposited. Assessment of sedimentological and soil mechanical characteristics of undisturbed top layer sediments from a manganese nodule field of the Peru Basin are necessary to provide baseline data for soil mechanical estimations and for the physical and numerical modelling of environmental impacts of future ocean mining activities. This will assist the International Seabed Authority to make decisions on how to formulate the mining code, and will increase our understanding of sedimentation processes in the Peru Basin. The deployment of a new sampling device (maxicorer) guaranteed undisturbed sediment samples in which soil mechanics-related parameters were measured including sediment density, water content, shear strength, and penetration force. Data evaluation show a close relationship between the soil mechanical parameters and various sedimentological properties such as grain-size distribution, mineral composition and micro-structure. From the results it can be concluded that in the worst case a deep-sea nodule mining vehicle would sink about 15-20 cm into the sea bed.

  5. Drainage architecture and sediment routing in erosive catchments within the Ebro Eiver sedimentary basin (NE Iberian Peninsula)

    NASA Astrophysics Data System (ADS)

    Castelltort, Xavier; Colombo, Ferran; Carles Balasch Solanes, Josep

    2016-04-01

    The Ebro Basin (EB) is the result of filling a foreland basin located between active mountain ranges during the Paleogene compressive phases, and later affected by phases of distension in the Neogene. The arrangement of filler material is monocline in the eastern margin and in the contact with the Catalan Coastal Range (CCR). This has repercussions on the model of emptying the erosive basins and in the drainage that took place in the margins of the original sedimentary basin. One can speak of a drainage architecture and sediment routing associated to a monocline erosive basin model. The monocline topography in the original margin of EB encouraged the formation of a string of erosive basins around the contact with CCR, which are the result of headward erosion towards the center of the EB of the rivers draining the CCR towards the Valencia Trough. At the time, the transition from the EB in its initial condition of endorheic to exorheic was through one of these monocline erosive basins. The erosive basins emptied by means of two vectors. On the one hand, growth in surface of the basin by deepening anaclinal streams through resistant beds of monocline stratigraphic succession that empty and link small depressions that increase laterally on the less resistant lithologic member. Moreover, the new drainage system entrenches as the exit point of the basin does, thanks to gradients created by distensional movements of the Neogene Valencia Trough. Growth and entrenchment model of river basins, as well as, sedimentary deposits and landforms generated by these processes are described and analyzed.

  6. Assessment of sediments in the riverine impoundments of national wildlife refuges in the Souris River Basin, North Dakota

    USGS Publications Warehouse

    Tangen, Brian A.; Laubhan, Murray K.; Gleason, Robert A.

    2014-01-01

    Accelerated sedimentation of reservoirs and riverine impoundments is a major concern throughout the United States. Sediments not only fill impoundments and reduce their effective life span, but they can reduce water quality by increasing turbidity and introducing harmful chemical constituents such as heavy metals, toxic elements, and nutrients. U.S. Fish and Wildlife Service national wildlife refuges in the north-central part of the United States have documented high amounts of sediment accretion in some wetlands that could negatively affect important aquatic habitats for migratory birds and other wetland-dependent wildlife. Therefore, information pertaining to sediment accumulation in refuge impoundments potentially is important to guide conservation planning, including future management actions of individual impoundments. Lands comprising Des Lacs, Upper Souris, and J. Clark Salyer National Wildlife Refuges, collectively known as the Souris River Basin refuges, encompass reaches of the Des Lacs and Souris Rivers of northwestern North Dakota. The riverine impoundments of the Souris River Basin refuges are vulnerable to sedimentation because of the construction of in-stream dams that interrupt and slow river flows and because of post-European settlement land-use changes that have increased the potential for soil erosion and transport to rivers. Information regarding sediments does not exist for these refuges, and U.S. Fish and Wildlife Service personnel have expressed interest in assessing refuge impoundments to support refuge management decisions. Sediment cores and surface sediment samples were collected from impoundments within Des Lacs, Upper Souris, and J. Clark Salyer National Wildlife Refuges during 2004–05. Cores were used to estimate sediment accretion rates using radioisotope (cesium-137 [137Cs], lead-210 [210Pb]) dating techniques. Sediment cores and surface samples were analyzed for a suite of elements and agrichemicals, respectively. Examination of

  7. Global Warming and Mass Extinctions Caused by Sediment Degassing of Volcanic Basins: Status Review

    NASA Astrophysics Data System (ADS)

    Planke, Sverre; Svensen, Henrik

    2010-05-01

    We have for the past decade worked on a hypothesis linking major environmental changes in Earth History to the eruption of Large Igneous Provinces (LIPs). It is well known that there are temporal correlations between LIPs and periods of global warming and/or mass extinctions. However, there are several problems explaining the environmental changes by extrusive volcanism. In particular, (1) there is no correlation between the size of a LIP and the environmental impact, (2) it is not possible to explain observed increases in isotopically light carbon by degassing of mafic magma, and (3) it is not sufficient carbon in mafic magma to explain the mass of atmospheric carbon needed to trigger global warming. Our hypothesis, initially published in 2004, stresses the emplacement environment. Sedimentary basins contain large volumes of volatiles or rocks that can be devolatized by heating. Magma intruding sedimentary basins will heat the host rock, causing massive degassing of the contact metamorphic aureoles. The type volatiles that are formed in the aureoles are strongly dependent on the host rock lithologies. Greenhouse gases, such as CH4 and CO2, are formed when organic-rich rocks or carbonates are heated, whereas poisonous gases (SO2, halocarbons, etc.) are formed when evaporate-rich sequences are heated. In contrast, only boiling (or formation of supercritical water) is taking place when barren sandstones or shales are heated. The sediment degassing hypothesis has been tested by focused studies of (1) the Paleocene-Eocene Thermal Maximum (PETM) and the Northeast Atlantic Igneous Province, (2) the Toarcian Oceanic Anoxic Event and the Karoo LIP, and (3) the end-Permian extinction and the Siberian Traps LIP. Borehole studies of aureole rocks in all three igneous provinces reveal a very high production potential of greenhouse gases. Heating experiments of petroleum-bearing evaporates from the Tunguska Basin in Siberia document that ozone-destroying halocarbons may have

  8. Sediment Quality and Comparison to Historical Water Quality, Little Arkansas River Basin, South-Central Kansas, 2007

    USGS Publications Warehouse

    Juracek, Kyle E.; Rasmussen, Patrick P.

    2008-01-01

    The spatial and temporal variability in streambed-sediment quality and its relation to historical water quality was assessed to provide guidance for the development of total maximum daily loads and the implementation of best-management practices in the Little Arkansas River Basin, south-central Kansas. Streambed-sediment samples were collected at 26 sites in 2007, sieved to isolate the less than 63-micron fraction (that is, the silt and clay), and analyzed for selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, and the radionuclides beryllium-7, cesium-137, lead-210, and radium-226. At eight sites, streambed-sediment samples also were collected and analyzed for bacteria. Particulate nitrogen, phosphorus, and organic carbon concentrations in the streambed sediment varied substantially spatially and temporally, and positive correlations among the three constituents were statistically significant. Along the main-stem Little Arkansas River, streambed-sediment concentrations of particulate nitrogen and phosphorus generally were larger at and downstream from Alta Mills, Kansas. The largest particulate nitrogen concentrations were measured in samples collected in the Emma Creek subbasin and may be related to livestock and poultry production. The largest particulate phosphorus concentrations in the basin were measured in samples collected along the main-stem Little Arkansas River downstream from Alta Mills, Kansas. Particulate nitrogen, phosphorus, and organic carbon content in the water and streambed-sediment samples typically decreased as streamflow increased. This inverse relation may be caused by an increased contribution of sediment from channel-bank sources during high flows and (or) increased particle sizes transported by the high flows. Trace element concentrations in the streambed sediment varied from site to site and typically were less than threshold-effects guidelines for possible adverse biological effects

  9. Assessment of sediment quality and pore water ecotoxicity in Kebir Rhumel basin (NE-Algeria): a combined approach.

    PubMed

    Sahli, Leila; Afri-Mehennaoui, Fatima-Zohra; El Hadef El Okki, Mohamed; Férard, Jean François; Mehennaoui, Smail

    2012-01-01

    The objectives of this study are to use different approaches to assess the current pollution status in the wadis of the Kebir Rhumel basin. First, sediment trace metal contents were measured by flame atomic absorption spectroscopy. Then, sediment quality was assessed on the basis of contamination assessment indexes such as: Geoaccumulation Index (Igeo), Contamination factor (C(f)), Contamination degree (C(d)), Sediment Pollution Index (SPI) and SEQ guidelines (Consensus Sediment Quality Guidelines). In addition, several toxicity tests (Daphnia magna mobility inhibition acute test-48 h, Aliivibrio fischeri luminescence inhibition acute test - 15/30 mn and Pseudokirchneriella subcapitata growth inhibition chronic test - 72 h) were conducted to assess sediment pore water ecotoxicity. Trace metal concentrations followed the order: Mn > Zn > Pb > Cr > Cu > Ni > Co > Cd. Indexes used indicate varying degrees of sediment quality. Igeo, C(f), C(d) and SPI reveal a polymetallic contamination dominated by two or more elements in which Cd, Cu and Pb are of greatest concern. SEQ guidelines showed that biological effects on fauna would likely be observed occasionally and/or frequently for Cd, Cr, Cu, Pb and Zn contents. Test organisms exposed to sediment pore water showed that the algal P. subcapitata test was more sensitive than the D. magna and A. fischeri tests. Hence, algal growth inhibition proved to be the most sensitive response to contaminants present in sediment extracts but a significant relationship with trace metal contents was not demonstrated. PMID:22233919

  10. Orbital forcing in the early Miocene alluvial sediments of the western Ebro Basin, Northeast Spain

    NASA Astrophysics Data System (ADS)

    Garces, M.; Larrasoaña, J. C.; Muñoz, A.; Margalef, O.; Murelaga, X.

    2009-04-01

    Paleoclimatic reconstructions from terrestrial records are crucial to assess the regional variability of past climates. Despite the apparent direct connection between continental sedimentary environments and climate, interpreting the climatic signature in ancient non-marine sedimentary sequences is often overprinted by source-area related signals. In this regard, foreland basins appear as non-ideal targets as tectonically-driven subsidence and uplift play a major control on the distribution and evolution of sedimentary environments and facies. Foreland basins, however, often yield among the thickest and most continuous stratigraphic records available on continents. The Ebro Basin (north-eastern Spain) is of particular interest among the circum-mediterranean alpine foreland basins because it evolved into a land-locked closed basin since the late Eocene, leading to the accumulation of an exceptionally thick (>5500 m) and continuous sequence of alluvial-lacustrine sediments over a period of about 25 Myr. In this paper we present a detailed cyclostratigraphic study of a 115 m thick section in the Bardenas Reales de Navarra region (western Ebro Basin) in order to test orbital forcing in the Milankovitch frequency band. The study section corresponds to the distal alluvial-playa mud flats which developed in the central sector of the western Ebro Basin, with sediments sourced from both the Pyrenean and Iberian Ranges. Sediments consist of brown-red alluvial clay packages containing minor fine-grained laminated sandstones sheet-beds and channels, grey marls and thin bedded lacustrine limestones arranged in 10 to 20 m thick fining-upwards sequences. Red clayed intervals contain abundant nodular gypsum interpreted as representing a phase of arid and low lake level conditions, while grey marls and limestones indicate wetter intervals recording the expansion of the inner shallow lakes. A magnetostratigraphy-based chronology indicates that the Peñarroya section represents a

  11. A molecular stable carbon isotope study of organic matter in immature Miocene Monterey sediments, Pismo basin

    NASA Astrophysics Data System (ADS)

    Schouten, Stefan; Schoell, Martin; Rijpstra, W. Irene C.; Sinninghe Damsté, Jaap S.; de Leeuw, Jan W.

    1997-05-01

    The 300 m section of the Miocene Monterey Formation outcropping at Shell Beach (Pismo basin; ca. 15-11 Ma) is composed of calcareous phosphatic (15.1-14.5 Ma) and siliceous facies (14.5-11.0 Ma). An objective of this paper is to document lateral paleoenvironmental changes in the Miocene Moneterey Formation by comparing the Shell Beach (SB) profile with the Naples Beach (NB) section in the Santa Barbara-Ventura basin (Schouten et al., 1997) which is ˜80 km to the south. Eight samples (one sample representing, on average, a time period of ca. 2000 y) from this section were analyzed for variations of extractable biomarkers and their carbon isotopic signatures as indicators for paleoenvironmental change during the Miocene. Saturated hydrocarbons present include 28,30-dinorhopane, phytane, n-alkanes (C 17sbnd C 31), lycopane, and 17β,21β(H)-homohopane. The biomarkers released after desulfurization of the polar fractions predominantly consist of phytane, 2,6,10,14-tetramethyl-7-(3-methylpentyl)pentadecane, C 17sbnd C 31n-alkanes, regular 5α- and 5β-steranes, dinosteranes, and (22R)-17β,21β(H)-pentakishomohopane. Steranes have similar carbon isotopic compositions (-25 to -27‰) throughout the section and are isotopically similar at both sites, indicating laterally similar and vertically stable environmental conditions for algae living in the upper part of the photic zone. Free and S-bound n-alkanes at SB mainly originate from marine organisms and not from terrestrial sources as in the NB section. S-bound pentakishomohopane is ca. 1-4‰ depleted compared to the steranes and is thought to be derived from the deeper water dwelling cyanobacteria. These findings are consistent with stable carbon isotopic data obtained for these compounds from Middle Miocene Monterey sediments at Naples Beach and indicates similar environmental conditions in the depositional environments of the Santa Barbara-Ventura and the Pismo basin. S-bound highly branched isoprenoids have, at both

  12. Sediment source areas of earthquake-triggered megaturbidites in marine or lacustrine confined basins: implications for regional paleoseismicity

    NASA Astrophysics Data System (ADS)

    emmanuel, Chapron; Hervé, Guyard; Flavio, Anselmetti; Giuseppe, Siani

    2016-04-01

    Earthquake triggered megaturbidites documented in different confined Mediterranean confined basins are bearing several similarities with so-called seiche deposits induced by earthquakes in several large and deep Alpine lakes. Both of these mega beds are resulting from coeval subaquatic slope failures and the propagation of violent waves developing erosive currents along shore lines and shallow water depths but also locally within deep waters. They have a similar acoustic signature (i.e. a decimetric to plurimetric transparent acoustic facies ponded in the deepest part of confined basins with a high-amplitude basal reflection) and are characterized by maximal thicknesses ranging between 0.2 and 1.6 % of the basin's water depth. While lacustrine megaturbidites are essentially resulting from the remobilization of fine-grained clastic sediments (either deltaic depot-centers or slopes loaded by sediment plumes during deglaciation) and shallow water coarser particles by waves and bottom currents; little is known about the soft-sediment source areas of megaturbidites in the Mediterranean. Based on our understanding of sedimentary process associated with seiche deposits in lakes and taking into consideration the oceanographic characteristics of the Mediterranean Sea, multiples soft-sediment source areas can be identified and a new conceptual depositional model can be proposed for the development of tsunamigenic earthquake-triggered megaturbidites.

  13. Polychlorinated dibenzo-p-dioxin and dibenzofuran concentration profiles in sediment and fish tissue of the Willamette Basin, Oregon

    USGS Publications Warehouse

    Bonn, B.A.

    1998-01-01

    Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) are highly hydrophobic compounds that have been implicated as carcinogens and, more recently, as estrogen disrupters. An occurrence and distribution study of these compounds in the Willamette Basin, Oregon, was conducted by the U.S. Geological Survey as part of the National Water-Quality Assessment Program. Bed sediment was collected from 22 sites; fish tissue was collected from eight sites. PCDD/F were found to be ubiquitous in Willamette Basin sediment. A distinct homolog profile, dominated by octachlorodibenzo-p-dioxin, was observed in sediment throughout the basin. The PCDD homolog profile was consistent at all sites, regardless of total PCDD/F concentration, presence of point sources, subbasin size, geographic location or land use. Principal components analysis revealed a gradient among the homolog profiles that showed increasing dominance of highly chlorinated congeners where human and industrial activity increased. Tissue and bed sediment obtained from the same site did not have similar PCDD/F concentrations or homolog profiles. Fish tissue showed enrichment in less chlorinated congeners and congeners with chlorine substitutions in the 2, 3, 7 and 8 positions.

  14. Determining the sources of suspended sediment in a Mediterranean groundwater-dominated river: the Na Borges basin (Mallorca, Spain).

    NASA Astrophysics Data System (ADS)

    Estrany, Joan; Martinez-Carreras, Nuria

    2013-04-01

    Tracers have been acknowledged as a useful tool to identify sediment sources, based upon a variety of techniques and chemical and physical sediment properties. Sediment fingerprinting supports the notion that changes in sedimentation rates are not just related to increased/reduced erosion and transport in the same areas, but also to the establishment of different pathways increasing sediment connectivity. The Na Borges is a Mediterranean lowland agricultural river basin (319 km2) where traditional soil and water conservation practices have been applied over millennia to provide effective protection of cultivated land. During the twentieth century, industrialisation and pressure from tourism activities have increased urbanised surfaces, which have impacts on the processes that control streamflow. Within this context, source material sampling was focused in Na Borges on obtaining representative samples from potential sediment sources (comprised topsoil; i.e., 0-2 cm) susceptible to mobilisation by water and subsequent routing to the river channel network, while those representing channel bank sources were collected from actively eroding channel margins and ditches. Samples of road dust and of solids from sewage treatment plants were also collected. During two hydrological years (2004-2006), representative suspended sediment samples for use in source fingerprinting studies were collected at four flow gauging stations and at eight secondary sampling points using time-integrating sampling samplers. Likewise, representative bed-channel sediment samples were obtained using the resuspension approach at eight sampling points in the main stem of the Na Borges River. These deposits represent the fine sediment temporarily stored in the bed-channel and were also used for tracing source contributions. A total of 102 individual time-integrated sediment samples, 40 bulk samples and 48 bed-sediment samples were collected. Upon return to the laboratory, source material samples were

  15. Sediment dynamics in the restored reach of the Kissimmee River Basin, Florida: A vast subtropical riparian wetland

    USGS Publications Warehouse

    Schenk, E.R.; Hupp, C.R.; Gellis, A.

    2012-01-01

    Historically, the Kissimmee River Basin consisted of a broad nearly annually inundated riparian wetland similar in character to tropical Southern Hemisphere large rivers. The river was channelized in the 1960s and 1970s, draining the wetland. The river is currently being restored with over 10 000 hectares of wetlands being reconnected to 70 river km of naturalized channel. We monitored riparian wetland sediment dynamics between 2007 and 2010 at 87 sites in the restored reach and 14 sites in an unrestored reference reach. Discharge and sediment transport were measured at the downstream end of the restored reach. There were three flooding events during the study, two as annual flood events and a third as a greater than a 5-year flood event. Restoration has returned periodic flood flow to the riparian wetland and provides a mean sedimentation rate of 11.3 mm per year over the study period in the restored reach compared with 1.7 mm per year in an unrestored channelized reach. Sedimentation from the two annual floods was within the normal range for alluvial Coastal Plain rivers. Sediment deposits consisted of over 20% organics, similar to eastern blackwater rivers. The Kissimmee River is unique in North America for its hybrid alluvial/blackwater nature. Fluvial suspended-sediment measurements for the three flood events indicate that a majority of the sediment (70%) was sand, which is important for natural levee construction. Of the total suspended sediment load for the three flood events, 3%–16% was organic and important in floodplain deposition. Sediment yield is similar to low-gradient rivers draining to the Chesapeake Bay and alluvial rivers of the southeastern USA. Continued monitoring should determine whether observed sediment transport and floodplain deposition rates are normal for this river and determine the relationship between historic vegetation community restoration, hydroperiod restoration, and sedimentation.

  16. Hazard mitigation related to water and sediment fluxes in the Yellow River basin, China, based on comparable basins of the United States

    USGS Publications Warehouse

    Osterkamp, W.R.; Gray, J.R.

    2003-01-01

    The Yellow River, north-central China, and comparative rivers of the western United States, the Rio Grande and the Colorado River, derive much of their flows from melting snow at high elevations, but derive most of their se diment loads from semiarid central parts of the basins. The three rivers are regulated by larg e reservoirs that store water and sediment, causing downstream channel scour and, farthe r downstream, flood hazard owing to re- deposition of sediment. Potential approaches to reducing continui ng bed aggradation and increasing flood hazard along the lower Yellow Ri ver include flow augmentation, retirement of irrigation that decreases flows and increas es erosion, and re-routing of the middle Yellow River to bypass large sediment i nputs of the Loess Plateau.

  17. Sources and transport of sediment, nutrients, and oxygen-demanding substances in the Minnesota River basin, 1989-92

    USGS Publications Warehouse

    Payne, G.A.

    1994-01-01

    The Minnesota River, 10 major tributaries, and 21 springs were sampled to determine the sources and transport of sediment, nutrients, and oxygen- demanding substances. The study was part of a four-year assessment of non-point source pollution in the Minnesota River Basin. Runoff from tributary watersheds was identified as the primary source of suspended sediment and nutrients in the Minnesota River mainstem. Suspended-sediment, phosphorus, and nitrate concentrations were elevated in all major tributaries during runoff, but tributaries in the south-central and eastern part of the basin produce the highest annual loading to the mainstem because of higher annual precipitation and runoff in that part of the basin. Particle-size analyses showed that most of the suspended sediment in transport consisted of silt- and clay-size material. Phosphorus enrichment was indicated throughout the mainstem by total phosphorus concentrations that ranged from 0.04 to 0.48 mg/L with a median value of 0.22 mg/L, and an interquartile range of 0.15 to 0.29 mg/L. Nitrate concentrations periodically exceeded drinking water standards in tributaries draining the south-central and eastern part of the basin. Oxygen demand was most elevated during periods of summer low flow. Correlations between levels of biochemical oxygen demand and levels of algal productivity suggest that algal biomass comprises much of the oxygen-demanding material in the mainstem. Transport of sediment, nutrients, and organic carbon within the mainstem was found to be conservative, with nearly all tributary inputs being transported downstream. Uptake and utilization of nitrate and orthophosphorus was indicated during low flow, but at normal and high flow, inputs of these constituents greatly exceeded biological utilization.

  18. Seafloor structure and uppermost sedimentation in the Pigafetta Basin, Magellan Seamount Chain, and East Mariana Basin of the Central-Western Pacific

    NASA Astrophysics Data System (ADS)

    Mathews, N. J.; Oakley, A. J.; Lizarralde, D.; Tominaga, M.; Tivey, M.; Sager, W. W.

    2013-12-01

    We conducted a marine geophysical survey of the Central-Western Pacific seafloor in 2011 aboard the R/V Thomas G. Thompson (TN272). Our survey imaged some of the oldest seafloor on the planet in a region of sparse data coverage. We present new (3.5 kHz) and bathymetry data from the Mesozoic Hawaiian magnetic lineations (Jurassic Quiet Zone) and a transect from the south end of the Pigafetta Basin (PB), west across the Magellan Seamount Chain (MSC) and the East Mariana Basin (EMB) to the Mariana Trench. The Chirp system penetrates the overlying sediment cover to a depth of ~50 meters below seafloor (mbsf). The deepest part of the Chirp record is marked by a strongly reflecting horizon, which occasionally crops out at the seafloor near volcanic peaks or bathymetric highs. Correlation of these data to DSDP/ODP drill sites (801C, 802, 199, 585) enables us to compare seafloor structure and uppermost sedimentation in the Jurassic Quiet Zone (JQZ), Pigafetta Basin, Magellan Seamounts, and the East Mariana Basin. Within the JQZ, and at the southern end of the PB, a 30- to 50-m-thick, acoustically-transparent sediment layer uniformly overlies the strongly reflecting horizon observed at water depths ranging from 4400m-5900m. We interpret this unit to be composed of pelagic abyssal clay and radiolarian oozes ubiquitous in the central-western Pacific. The basal horizon in this region is most likely formed by a layer of chert-porcelanite. In the southeastern PB (161.3 E, 17 N), this horizon reaches the seafloor at a depth of 5650 m and the transparent sediment package is truncated. In the region of the MSC, ~115 km north of drill sites 199 and 585, Chirp data show numerous volcanic peaks and a 50-m-thick sequence of stratified reflections. Volcaniclastics likely contribute to the layering. We first observe the stratified sediment package near 156.7 E, 15 N after a gap in data coverage. The sediment layer thins to the west and onlaps the basal horizon near the base of a seamount

  19. Paleomagnetic and paleoenvironmental implications of magnetofossil occurrences in late Miocene marine sediments from the Guadalquivir Basin, SW Spain

    PubMed Central

    Larrasoaña, Juan C.; Liu, Qingsong; Hu, Pengxiang; Roberts, Andrew P.; Mata, Pilar; Civis, Jorge; Sierro, Francisco J.; Pérez-Asensio, José N.

    2014-01-01

    Although recent studies have revealed more widespread occurrences of magnetofossils in pre-Quaternary sediments than have been previously reported, their significance for paleomagnetic and paleoenvironmental studies is not fully understood. We present a paleo- and rock-magnetic study of late Miocene marine sediments recovered from the Guadalquivir Basin (SW Spain). Well-defined paleomagnetic directions provide a robust magnetostratigraphic chronology for the two studied sediment cores. Rock magnetic results indicate the dominance of intact magnetosome chains throughout the studied sediments. These results provide a link between the highest-quality paleomagnetic directions and higher magnetofossil abundances. We interpret that bacterial magnetite formed in the surface sediment mixed layer and that these magnetic particles gave rise to a paleomagnetic signal in the same way as detrital grains. They, therefore, carry a magnetization that is essentially identical to a post-depositional remanent magnetization, which we term a bio-depositional remanent magnetization. Some studied polarity reversals record paleomagnetic directions with an apparent 60–70 kyr recording delay. Magnetofossils in these cases are interpreted to carry a biogeochemical remanent magnetization that is locked in at greater depth in the sediment column. A sharp decrease in magnetofossil abundance toward the middle of the studied boreholes coincides broadly with a major rise in sediment accumulation rates near the onset of the Messinian salinity crisis (MSC), an event caused by interruption of the connection between the Mediterranean Sea and the Atlantic Ocean. This correlation appears to have resulted from dilution of magnetofossils by enhanced terrigenous inputs that were driven, in turn, by sedimentary changes triggered in the basin at the onset of the MSC. Our results highlight the importance of magnetofossils as carriers of high-quality paleomagnetic and paleoenvironmental signals even in

  20. Using U-Pb Detrital Zircon to Identify Evolution of Sediment Drainage in the South Central Pyrenean Foreland Basin, Spain

    NASA Astrophysics Data System (ADS)

    Clark, J. D.; Stockli, D. F.; McKay, M. P.; Thomson, K.; Puigdefabregas, C.; Castelltort, S.; Dykstra, M.; Fildani, A.

    2014-12-01

    Until the 2011 Mw9.0 Tohoku earthquake, the role of earthquakes as agents of sediment dispersal and deposition at erosional trenches was largely under-appreciated. A series of cruises carried out after the 2011 event has revealed a variety of unsuspected sediment transport mechanisms, such as tsunami-triggered sheet turbidites, suggesting that great earthquakes may in fact be important agents for dispersing sediments across trench slopes. To complement these observational data, we have modeled the pathways of sediments across the trench slope based on bathymetric grids. Our approach assumes that transport direction is controlled by slope azimuth only, and ignores obstacles smaller than 0.6-1 km; these constraints are meant to approximate the behavior of turbidites. Results indicate that (1) most pathways issued from the upper slope terminate near the top of the small frontal wedge, and thus do not reach the trench axis; (2) in turn, sediments transported to the trench axis are likely derived from the small frontal wedge or from the subducting Pacific plate. These results are consistent with the stratigraphy imaged in seismic profiles, which reveals that the slope apron does not extend as far as the frontal wedge, and that the thickness of sediments at the trench axis is similar to that of the incoming Pacific plate. We further applied this modeling technique to the Cascadia, Nankai, Middle-America, and Sumatra trenches. Where well-defined canyons carve the trench slopes, sediments from the upper slope may routinely reach the trench axis (e.g., off Costa Rica and Cascadia). In turn, slope basins that are isolated from the canyons drainage systems must mainly accumulate locally-derived sediments. Therefore, their turbiditic infill may be diagnostic of seismic activity only - and not from storm or flood activity. If correct, this would make isolated slope basins ideal targets for paleoseismological investigation.

  1. Thermochronological Constraints on Detrital Sediments of the Late Permian Karoo Basin: Insights Into Uplift History of the Cape Fold Belt

    NASA Astrophysics Data System (ADS)

    Tohver, E.; Arosio, R.; Schmieder, M.; Jourdan, F.; Wilson, A.; Flint, S.

    2012-12-01

    The Karoo Basin and its equivalents cover most of southern Africa, with correlative basins found also in South America. The vast geographic expanse of these basins indicates a common history of deposition along the active Panthalassan margin of southern Gondwana. The early Paleozoic history of the Karoo Basin is marked by early glacio-marine to later shallow marine-deltaic sedimentation with a final shift to a continental setting by the late Permian. In South Africa, this transition to a fluvial environment is defined by the deposition of the Beaufort Group, a ca. 5 km thick sequence of meandering river channel sandstones and muddy overbank deposits. We have identified an 800 m thick sequence of the lowermost Beaufort Group where magnetostratigraphy and U-Pb dating of zircon in volcanic tuffs establish a depositional age of 264-268 Ma. Detrital zircon from sandstone samples were dated by U-Pb SHRIMP, revealing age populations typical of the cratonic/metamorphic provinces of the Kalahari craton (Kaapval and Namaqua-Natal provinces) as well as late Paleozoic magmatic zircons probably from southern South America. Populations of detrital muscovite dated using the 40Ar/39Ar step-heating technique are dominated by a tight cluster of ca. 272 Ma cooling ages, indicating rapid exhumation of the tectonically active Cape Fold belt and short lag times (4-8 Ma) for detritus deposited into the Karoo foreland basin, similar to rates observed for modern sediments of Himalayan-draining rivers. Ongoing work will reveal whether the Cape Belt is the source for the sediments of the Karoo foreland basin.

  2. The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin

    NASA Astrophysics Data System (ADS)

    Lopez-Gamundi, O. R.; Conaghan, P. J.; Rossello, E. A.; Cobbold, P. R.

    1995-04-01

    The Tunas Formation, extensively exposed in the Sierras Australes foldbelt of eastern central Argentina, completes the sedimentation of the Gondwanan (Late Carboniferous-Permian) sequence, locally known as the Pillahuincó Group. The underlying units of the Group show an integrated depositional history which can be explained in terms of glaciomarine sedimentation (Sauce Grande Formation) and postglacial transgression (Piedra Azul and Bonete Formations). This succession also has a rather uniform quartz-rich, sand-sized composition indicative of a cratonic provenance from the Tandilia Massif to the northeast. Early to Late Permian deformation folded and thrusted the southwestern basin margin (Sierras Australes) and triggered the deposition of a 1,500 m — thick, synorogenic prograding wedge, the Tunas Formation, in the adjacent foreland basin (Sauce Grande or Claromecó Basin). Sandstone detrital modes for the Tunas deposits show moderate to low contents of quartz and abundant lithics, mostly of volcanic and metasedimentary origin. Paleocurrents are consistently from the SW. Tuffs interbedded with sandstones in the upper half of Tunas Formation (Early — early Late? Permian) are interpreted as being derived from volcanic glass-rich tuffs settled in a body of water. Extensive rhyolitic ignimbrites and consanguineous airborne tuffaceous material erupted in the northern Patagonian region during that period. The age constraints and similarities in composition between these volcanics and the tuffaceous horizons present in the Sauce Grande, Parana and Karoo Basins suggest a genetic linkage between these two episodes. The intimate relationship between volcanic activity inboard of the paleo-Pacific margin, deformation in the adjacent orogenic belt and subsidence and sedimentation in the contiguous foreland basin constitutes a common motif in the Sauce Grande and Karoo Basins of southwestern Gondwana.

  3. Characteristics of hydrothermal sedimentation process in the Yanchang Formation, south Ordos Basin, China: Evidence from element geochemistry

    NASA Astrophysics Data System (ADS)

    He, Cong; Ji, Liming; Wu, Yuandong; Su, Ao; Zhang, Mingzhen

    2016-11-01

    Hydrothermal sedimentation occurred in the Triassic Yanchang Formation, Ordos Basin, China. However, their macroscopic features at the scale of the stratum and hydrothermal sources still lack correlational research. This paper performed element geochemical study on a large number of core samples collected from the Yanchang Formation of a new drilling well located in the south Ordos Basin. The SiO2/(K2O + Na2O) vs. MnO/TiO2 crossplot and Fe vs. Mn vs. (Cu + Co + Ni) × 10 ternary diagram demonstrate that the Yanchang stratum in the study area has, in general, hydrothermal components. The Al/(Al + Fe + Mn) and (Fe + Mn)/Ti ratios of the core samples range from 0.34 to 0.84 and 4.81 to 50.54, averaging 0.66 and 10.67, respectively, indicating that the stratum is a set of atypical hydrothermal sedimentation with much terrigenous input. Data analysis shows that the hydrothermal source in the study area was from the deep North Qinling Orogen around the south margin of the basin, where some active tectonic and volcanic activities took place, rather than from the relatively stable internal basin. Early Indosinian movement and volcanic activities activated basement faults around the southern margin of the basin, providing vents for the deep hydrothermal fluid upwelling. The hydrothermal indicators suggest that the study area experienced 4 episodes of relatively stronger hydrothermal activity, namely during the Chang 10, Chang 9-1, Chang 7-3 and Chang 6-2 periods. We also propose a new hydrothermal sedimentation model of hydrothermal fluids overflowing from basin margin faults, for the Yanchang Formation, which is reported here for the first time.

  4. The effect of mining and related activities on the sediment trace element geochemistry of the Spokane River Basin, Washington, USA

    USGS Publications Warehouse

    Grosbois, C.A.; Horowitz, A.J.; Smith, J.J.; Elrick, K.A.

    2002-01-01

    Surface sediments in the Spokane River Basin are enriched in Pb, Zn, As, Cd, Sb, and Hg relative to local background levels. Maximum enrichment occurs in the Upper Spokane River in close proximity to Lake Coeur d'Alene. On average, enrichment decreases downstream. Subsurface sediments also are enriched in Pb, Zn, As, Cd, Sb, and Hg relative to background levels. Enrichment began between 1900 and 1920 in the middle of the basin; this is contemporaneous with similar findings in Lake Coeur d'Alene (the upstream source of the Spokane River), as well as the completion of Long Lake Dam (1913). In the most downstream part of the basin, enrichment began between 1930 and 1940. This temporal shift may reflect the latter's greater distance from the Coeur d'Alene River Basin, the presumptive source of the enriched trace elements, but is more likely the result of the completion of Grand Coulee Dam (1934-1941) which backed up the Spokane River, and elevated water levels by about 30 m in the most downstream part of the basin.

  5. Effects of urbanization on streamflow and sediment transport in the Rock Creek and Anacostia River basins, Montgomery County, Maryland, 1962-74

    USGS Publications Warehouse

    Yorke, Thomas H.; Herb, William J.

    1978-01-01

    Land use, precipitation, streamflow, and sediment discharge data were collected from nine small drainage basins in Montgomery County, Maryland, to evaluate runoff and sediment response to sediment-control practices in areas undergoing urban development. Drainage basins ranged in size from 0.35 to 21.1 sq mi and land use ranged from rural to 60 percent urban. Urbanization did not affect low and medium flows, but it did result in increased storm runoff and peak flows. Suspended sediment transported from one of the basins that underwent urban development, the 21.1 sq mi Anacostia River basin, averaged 15 ,400 tons/yr between 1962 and 1974. Bedload was estimated as 5 to 11 percent of the total load. Cropland, urban land, and construction sites were the major sources of sediment. Average annual sediment yields ranged from 065 to 4.3 tons/acre for cropland, 3.7 tons/acre for urban land, and 7 to 100 tons/acre for urban construction sites. The magnitude of the yields from construction sites was significantly affected by (1) the slope of the sites, (2) the proximity of stream channels, (3) buffer zones of natural vegetation, and (4) sediment-control measures. Sediment controls, particularly those enforced under a 1971 sediment-control ordinance, apparently decreased construction-site sediment yields by 60 to 80 percent. (Woodard-USGS)

  6. Sedimentation of shelf sandstones in Queen Formation, McFarland and Means fields, central basin platform of Permian basin

    SciTech Connect

    Malicse, A.; Mazzullo, J.; Holley, C.; Mazzullo, S.J.

    1988-01-01

    The Queen Formation is a sequence of carbonates, evaporites, and sandstones of Permian (Guadalupian) age that is found across the subsurface of the Central Basin platform of the Permian basin. The formation is a major hydrocarbon reservoir in this region, and its primary reservoir facies are porous shelf sandstones and dolomites. Cores and well logs from McFarland and Means fields (on the northwest margin of the Central Basin platform) were examined to determine the sedimentary history of the shelf sandstones.

  7. Simulation of streamflow and sediment transport in two surface-coal-mined basins in Fayette County, Pennsylvania

    USGS Publications Warehouse

    Sams, J. I.; Witt, E. C.

    1995-01-01

    The Hydrological Simulation Program - Fortran (HSPF) was used to simulate streamflow and sediment transport in two surface-mined basins of Fayette County, Pa. Hydrologic data from the Stony Fork Basin (0.93 square miles) was used to calibrate HSPF parameters. The calibrated parameters were applied to an HSPF model of the Poplar Run Basin (8.83 square miles) to evaluate the transfer value of model parameters. The results of this investigation provide information to the Pennsylvania Department of Environmental Resources, Bureau of Mining and Reclamation, regarding the value of the simulated hydrologic data for use in cumulative hydrologic-impact assessments of surface-mined basins. The calibration period was October 1, 1985, through September 30, 1988 (water years 1986-88). The simulated data were representative of the observed data from the Stony Fork Basin. Mean simulated streamflow was 1.64 cubic feet per second compared to measured streamflow of 1.58 cubic feet per second for the 3-year period. The difference between the observed and simulated peak stormflow ranged from 4.0 to 59.7 percent for 12 storms. The simulated sediment load for the 1987 water year was 127.14 tons (0.21 ton per acre), which compares to a measured sediment load of 147.09 tons (0.25 ton per acre). The total simulated suspended-sediment load for the 3-year period was 538.2 tons (0.30 ton per acre per year), which compares to a measured sediment load of 467.61 tons (0.26 ton per acre per year). The model was verified by comparing observed and simulated data from October 1, 1988, through September 30, 1989. The results obtained were comparable to those from the calibration period. The simulated mean daily discharge was representative of the range of data observed from the basin and of the frequency with which specific discharges were equalled or exceeded. The calibrated and verified parameters from the Stony Fork model were applied to an HSPF model of the Poplar Run Basin. The two basins are in

  8. Development of the Côte Ivoire Basin: reading provenance, sediment dispersal, and geodynamic implications from heavy minerals

    NASA Astrophysics Data System (ADS)

    Wozazek, Stefan; Krawinkel, Hannelore

    2002-05-01

    The combined approach of conventional and varietal heavy mineral analysis was applied to constrain changes in source rock area, dispersal routes of detritus, and geodynamic setting of the Upper Cretaceous to Neogene Côte d'Ivoire basin. The heavy mineral assemblage of Albian to Turonian sediments reflect a narrow source rock area and short transport distances. A prominent change in the heavy mineral association of Late Cenomanian to Neogene sediments indicates enlargement of source area and longer fluvial transport distances, or longer storage of sediment within the littoral energy fence. The sudden change within the heavy mineral associations marks the transition from the late syn-rift stage to the early passive margin stage of the Southern Atlantic. During Albian to Late Cenomanian time, the basin geometry was mainly controlled by steep slopes and sediments were transported directly to the depocenter. The situation changed in Late Cenomanian time. A small shelf area developed where sediments from different sources were mixed and reworked before deposition. We believe that the W-E direction of the long-shore drift, which transports today huge quantities of near-shore sand, was established at the end of the Paleogene. This resulted from the drifting of southern West Africa across the paleoequator and subsequent change in surface wind directions.

  9. Trace metal fractionation as a mean to improve on the management of contaminated sediments from runoff water in infiltration basins.

    PubMed

    Al Husseini, Amelène El-Mufleh; Béchet, Béatrice; Gaudin, Anne; Ruban, Véronique

    2013-01-01

    The management of stormwater sediment is a key issue for local authorities due to the pollution load and significant tonnages. In view of reuse, for example for civil engineering, the environmental evaluation of these highly aggregated sediments requires the study of the fractionation and mobility of trace metals. The distribution of trace metals (Cd, Cr, Cu, Ni, Pb, Zn) and their level of lability in three French stormwater sediments was determined using sequential and kinetic extractions (EDTA reagent) associated with mineralogical analysis and scanning electron microscopy observations. Using microanalysis, new data were acquired on the evolution of aggregate state during extractions, and on its significant role in the retention of trace metals. Trace metals were, in particular, observed to be very stable in small aggregates (10-50 microm). Comparison of the two extraction methods revealed that EDTA extraction was not convenient for evaluating the stable fraction of Cr, Ni and Zn. Moreover, the results were relevant for basins presenting similar sources of trace metals, whatever the physicochemical conditions in basins. The results suggest that the management of stormwater sediments could be improved by a better knowledge of metal mobility, as chemical extractions could highlight the localization of the mobile fraction of trace metals. Treatment could be therefore avoided, or specific treatment could be applied to a reduced volume of sediments.

  10. Trace metal fractionation as a mean to improve on the management of contaminated sediments from runoff water in infiltration basins.

    PubMed

    Al Husseini, Amelène El-Mufleh; Béchet, Béatrice; Gaudin, Anne; Ruban, Véronique

    2013-01-01

    The management of stormwater sediment is a key issue for local authorities due to the pollution load and significant tonnages. In view of reuse, for example for civil engineering, the environmental evaluation of these highly aggregated sediments requires the study of the fractionation and mobility of trace metals. The distribution of trace metals (Cd, Cr, Cu, Ni, Pb, Zn) and their level of lability in three French stormwater sediments was determined using sequential and kinetic extractions (EDTA reagent) associated with mineralogical analysis and scanning electron microscopy observations. Using microanalysis, new data were acquired on the evolution of aggregate state during extractions, and on its significant role in the retention of trace metals. Trace metals were, in particular, observed to be very stable in small aggregates (10-50 microm). Comparison of the two extraction methods revealed that EDTA extraction was not convenient for evaluating the stable fraction of Cr, Ni and Zn. Moreover, the results were relevant for basins presenting similar sources of trace metals, whatever the physicochemical conditions in basins. The results suggest that the management of stormwater sediments could be improved by a better knowledge of metal mobility, as chemical extractions could highlight the localization of the mobile fraction of trace metals. Treatment could be therefore avoided, or specific treatment could be applied to a reduced volume of sediments. PMID:24191459

  11. Zinc mobility in an infiltration basin (Lyon city, France): constraints from Zn stable isotope ratios in the plant and sediment

    NASA Astrophysics Data System (ADS)

    Queyron, M.; Aucour, A.-M.; Pichat, S.; Saulais, M.; Bedell, J.-P.

    2012-04-01

    Infiltration basins are stormwater management techniques that are widely used. The settling of stormwater particles leads to a contaminated sediment layer. Wild plants can colonize these basins. They can play a role on the fate of heavy metals either directly by uptake or indirectly by modifying the forms of the metal in the sediment. Plant interactions with metals depend on a large number of factors, including the type of metal, the plant species and plant's growth stage. Moreover, during the dormant period of each year, the shoots die back. The resulting dead matter is returned to the basin substrate where it gradually decomposes through a combination of leaching and biological action that implicates a complete cycle for metal mobility. In order to model the metal cycle in the system, we consider the plant root, aerial part, litter deposits, sediments as the main Zn pools. The aim of this study is to assess the Zn mobility between these pools. The Zn concentration and isotope ratios were analyzed in the different Zn pools for two dominant species of the studied infiltration basin (Phalaris arundinaceae, Typha latifolia) and for a complete biological cycle from spring to winter. Zn stable isotopes are expected to fractionate with plant uptake and translocation and thus can help to assess the effect of the plant biochemical processes on Zn mobility. Whilst the sediments (1100-1400 ppm Zn DW) and litter (600 ppm) are highly concentrated in Zn, the plant aerial parts (100-250 ppm) are less concentrated than the roots (200-400 ppm). The ^66Zn significantly differ between the sediment (0.15 to 0.19‰) and aerial parts of the plants (-0.03 to -0.08‰) hence confirming the occurrence of depletion in heavy isotopes with plant uptake and translocation to shoot. The ^66Zn of roots fall close to the sediment. The roots show a small depletion in heavy isotopes between mid-summer (0.18‰) and winter (0.27‰). This observation and the fact that the litter is enriched in

  12. Asymmetric geometry of a half-graben basin as indicated by sediment character: An example from the Diligencia Basin, southeastern California

    SciTech Connect

    Davisson, C.M.; Law, R.D.; Eriksson, K.A. . Dept. of Geological Science)

    1992-01-01

    Sedimentation on the northern side of the basin is characterized by the development of a large scale apron of coallesced alluvial fan deposits. The northern part of the apron is composed of gently dipping, matrix supported, oligomictic granite boulder breccias. Traced southwards, these deposits appear to pass into well-rounded clast-supported cobble-boulder conglomerates containing lensoidal sandbodies as well as examples of clast alignment and imbrication. In contrast, on the southern margin of the Diligencia Basin the steeply dipping Diligencia Formation is composed of fluvial cross-bedded sandstones with minor pebble-cobble conglomerates. The deposits exhibit a notable along-strike grain size variation. The very coarse nature of the sediments on the northern margin indicates deposition along an extremely steep elevation gradient. Some of the blocks may measure tens to hundreds of meters in dimension and represent catastrophic gravity glide events. On the southern side of the basin, although much of the fans have been removed by subsequent erosion, the coarsest deposits are debris flow deposits which must represent a relatively proximal position on the fan. The contrasting character of the lower units of the Diligencia Formation suggests the primary geometric asymmetry of a developing, half-graben basin. The high-gradient deposits in the north are interpreted to represent deposition along the escarpment of a basinward-dipping detachment fault system, whereas the finer sediments of the southern margin must represent low-gradient alluvial fans forming on the gently sloping hanging wall of the half-graben.

  13. Reconnaissance of pharmaceuticals and wastewater indicators in streambed sediments of the lower Columbia River basin, Oregon and Washington

    USGS Publications Warehouse

    Nilsen, Elena; Furlong, Edward T.; Rosenbauer, Robert

    2014-01-01

    One by-product of advances in modern chemistry is the accumulation of synthetic chemicals in the natural environment. These compounds include contaminants of emerging concern (CECs), some of which are endocrine disrupting compounds (EDCs) that can have detrimental reproductive effects. The role of sediments in accumulating these types of chemicals and acting as a source of exposure for aquatic organisms is not well understood. Here we present a small-scale reconnaissance of CECs in bed sediments of the lower Columbia River and several tributaries and urban streams. Surficial bed sediment samples were collected from the Columbia River, the Willamette River, the Tualatin River, and several small urban creeks in Oregon. Thirty-nine compounds were detected at concentrations ranging from 1,000 ng [g sediment]-1 dry weight basis. Columbia River mainstem, suggesting a higher risk of exposure to aquatic life in lower order streams. Ten known or suspected EDCs were detected during the study. At least one EDC was detected at 21 of 23 sites sampled; several EDCs were detected in sediment from most sites. This study is the first to document the occurrence of a large suite of CECs in the sediments of the Columbia River basin. A better understanding of the role of sediment in the fate and effects of emerging contaminants is needed.

  14. Paleo-basin hydrology and sediment transport in the Pisco Valley, Peru

    NASA Astrophysics Data System (ADS)

    bekaddour, toufik; schlunegger, fritz

    2013-04-01

    Quantitative data on sediment transport and climatic changes allow the understanding of alluvial river processes such as aggradation, degradation, vertical and lateral incision and valley widening. Here, we focus on the ca. 4.5*103 km^2-large Pisco drainage basin on the western Pacific side of the Andes, central Peru, which is currently a desert with precipitation rates decreasing form 800 mm/yr on the Altiplano, to 10 mm/yr at the coast. While higher precipitation rates than at present have been inferred from lake level highstands on the Altiplano between 48 and 36 Ka PB (Minchin period), no quantitative estimates about water budgets for that time have been presented so far. Here we use the stratigraphic archives from the Pisco Valley and explore relationships between: (i) the particle size of bedload and the shear stress conditions needed for their entrainment, and (ii) the basin hydrology and channel adjustment for the present time and the Minchin pluvial period between 48 to 36 ka BP when sediment aggradation resulting in the build-up of ca. 50 km-thick terrace sequences. We find that the bedload material is generally more coarse-grained in the terrace deposits than in modern longitudinal bars. In particular, grain size measurements reveal that the mean D50 and D84 of the modern deposits are about 100 and 170 mm, respectively. Meanwhile the mean D50 and D84 inferred from measurements of the terrace deposits are ca. 150 and 310 mm. Our results reveal that the current mean annual discharge Q=60 m^3/s of the Pisco River is just refreshing the flat middle reaches and transporting the coarse particles in the steep higher reaches at near critical threshold. On the other hand, the hydraulic analyses based on the D50 of the Pisco River reveal that a critical discharge of Q=300 m^3/s is required to transport the D84 along the entire channel, and a discharge of this magnitude could rearrange the entire channel morphology except for the downstream reaches where the coarse

  15. Large Sanjiang basin groups outside of the Songliao Basin Meso-Senozoic Tectonic-sediment evolution and hydrocarbon accumulation

    NASA Astrophysics Data System (ADS)

    Zheng, M.; Wu, X.

    2015-12-01

    The basis geological problem is still the bottleneck of the exploration work of the lager Sanjiang basin groups. In general terms, the problems are including the prototype basins and basin forming mechanism of two aspects. In this paper, using the field geological survey and investigation, logging data analysis, seismic data interpretation technical means large Sanjiang basin groups and basin forming mechanism of the prototype are discussed. Main draw the following conclusions: 1. Sanjiang region group-level formation can be completely contrasted. 2. Tension faults, compressive faults, shear structure composition and structure combination of four kinds of compound fracture are mainly developed In the study area. The direction of their distribution can be divided into SN, EW, NNE, NEE, NNW, NWW to other groups of fracture. 3. Large Sanjiang basin has the SN and the EW two main directions of tectonic evolution. Cenozoic basins in Sanjiang region in group formation located the two tectonic domains of ancient Paleo-Asian Ocean and the Pacific Interchange. 4. Large Sanjiang basin has experienced in the late Mesozoic tectonic evolution of two-stage and nine times. The first stage, developmental stage basement, they are ① Since the Mesozoic era and before the Jurassic; ② Early Jurassic period; The second stage, cap stage of development, they are ③ Late Jurassic depression developmental stages of compression; ④ Early Cretaceous rifting stage; ⑤ depression in mid-Early Cretaceous period; ⑥ tensile Early Cretaceous rifting stage; ⑦ inversion of Late Cretaceous tectonic compression stage; ⑧ Paleogene - Neogene; ⑨ After recently Ji Baoquan Sedimentary Ridge. 5. Large Sanjiang basin group is actually a residual basin structure, and Can be divided into left - superimposed (Founder, Tangyuan depression, Hulin Basin), residual - inherited type (Sanjiang basin), residual - reformed (Jixi, Boli, Hegang basin). there are two developed depression and the mechanism

  16. Anastomosing river deposits, sedimentation rates and basin subsidence, Magdalena River, northwestern Colombia, South America

    NASA Astrophysics Data System (ADS)

    Smith, Derald G.

    1986-02-01

    Situated in a tectonically active foreland basin, the Magdalena River consists of vertically accreting, levee-confined channels and adjacent extensive wetlands, which are interpreted as an anastomosing river sedimentary system. Equivalent rates of basin filling and subsidence average 3.8 mm yr -1 based on 18 14C dates from five bore holes drilled to depths of 55 m and sediment transport budgets from 35 years of measurement. Located in a savanna-tropical climate, anastomosing river deposits of the Magdalena are remarkably similar to the anastomosing deposits of the upper Columbia River in a temperate-cold climate in western Canada, suggesting that climate is not a controlling factor of anastomosis. The geometry of anastomosing channel-fills in the Magdalena consists of stratigraphically non-uniform, low sinuous, narrow stringers of sand up to 30 m thick by 600 m wide, a width-depth ratio of 20. Thin (1-2 m) off-channel crevasse-splay sand sheets extend laterally up to 10 km distance. When buried, both sand deposits become encased by lacustrine or marsh mud to form stratigraphic traps. While there are few modern anastomosing river systems as compared to braiding and meandering, there may be a disproportionately large number of ancient anastomosed fluvial rock sequences due to the rapid rate of vertical accretion. Such a different depositional style and geometry of sand bodies have considerable significance in the interpretation of some ancient fluvial rock sequences because it provides an alternative to the meandered and braided-river deposition models.

  17. A molecular stable carbon isotope study of organic matter in immature Miocene Monterey sediments, Pismo basin

    SciTech Connect

    Schouten, S.; Rijpstra, I.C.; De Leeuw, J.W.

    1997-05-01

    The 300 m section of the Miocene Monterey Formation outcropping at Shell Beach is composed of calcareous phosphatic (15.1 -14.5 Ma) and siliceous facies (14.5-11.0 Ma). An objective of this paper is to document lateral paleoenvironmental changes in the Miocene Monterey Formation by comparing the Shell Beach (SB) profile with the Naples Beach (NB) section in the Santa Barbara-Ventura basin. Eight samples (one sample representing, on average, a time period of ca. 2000 y) from this section were analyzed for variations of extractable biomarkers and their carbon isotopic signatures as indicators for paleoenvironmental change during the Miocene. Saturated hydrocarbons present include 28,30-dinorhopane, phytane, n-alkanes (C{sub 17}-C{sub 31}), lycopane, and 17{beta}, 21{beta}(H)-homohopane. The biomarkers released after desulfurization of the polar fractions predominantly consist of phytane, 2,6.10,14-tetramethyl-7-(3-methylpentyl)pentadecane, C{sub 17}-C{sub 31} n-alkanes. regular 5{alpha}- and 5{beta}-steranes, dinosteranes, and (22R)-17{beta},21{beta}(H)-pentakishomohopane. Steranes have similar carbon isotopic compositions (-25 to -27{per_thousand}) throughout the section and are isotopically similar at both sites, indicating laterally similar and vertically stable environmental conditions for algae living in the upper part of the photic zone. Free and S-bound n-alkanes at SB mainly originate from marine organisms and not from terrestrial sources as in the NB section. S-bound pentakishomohopane is ca. 1-49{per_thousand} depleted compared to the steranes and is thought to be derived from the deeper water dwelling cyanobacteria. These findings are consistent with stable carbon isotopic data obtained for these compounds from Middle Miocene Monterey sediments at Naples Beach and indicates similar environmental conditions in the depositional environments of the Santa Barbara-Ventura and the Pismo basin. 64 refs., 14 figs., 6 tabs.

  18. Erosion in the Western Alps (Dora Baltea basin). 1. Quantifying sediment provenance

    NASA Astrophysics Data System (ADS)

    Vezzoli, Giovanni; Garzanti, Eduardo; Monguzzi, Stefano

    2004-10-01

    Sourced in the M. Bianco, the highest mountain of the Alps, the Dora Baltea River cuts across the arc of the Western Alps, drains all major Alpine tectonic units from the Helvetic domain to the South alpine domain, and finally joins the Po River. Petrographic composition of clastic detritus carried by the Dora Baltea River and its tributaries faithfully mirrors the complex geology of the Western Alps. High-resolution modal analysis of Dora Baltea sands allowed us to distinguish seven end-member metamorphoclastic provenances. River sands from the M. Bianco External Massif are dominated by quartz, feldspars, and hornblende. Detritus from basement and cover rocks of the Briançonnais zone includes low-grade metasedimentary lithic fragments, epidote, chloritoid, and garnet. Sands from the Internal Penninic Massifs include quartz and subordinate feldspars, garnet, and epidote. Abundant metabasite and serpentine-schist lithic grains, along with epidote, actinolite, and few pyroxenes, characterize detritus from the calcschists and meta-ophiolites of the oceanic Piemonte zone. Sands from the Austroalpine zone include quartz, abundant metamorphic lithic fragments, garnet, and locally significant sillimanite (Dent Blanche kinzigites). The relative contribution of each end member to the Dora Baltea sediment flux was assessed with forward modelling of end-member mixing. Our estimates, calculated from the entire petrographic and mineralogical data set, indicate that the main sources of bed load in the Dora Baltea mountain basin are the granitoid to gneissic rocks exposed in the M. Bianco Massif and in the Austroalpine zone. In order to make allowance for the contribution of a particular bedrock constituent in a compound source area to the derivative sand, the original concept of sand generation index (SGI) was modified to assess the relative contribution of the seven end-member sources of detritus. The highest total-basin SGI indices are calculated for the M. Bianco Massif (SGI

  19. An Integrated Geochemical and Facies Analysis of Paleogene Aged Fluvio-Lacustrine Sediments in the Petrockstow and Bovey Basins, UK

    NASA Astrophysics Data System (ADS)

    Chaanda, Mohammed S.; Jerrett, Rhodri; Grimes, Stephen T.; Price, Gregory D.; Anderson, Mark

    2014-05-01

    The Petrockstow and Bovey basins are two similar pull apart (strike slip) basins belonging to the Sticklepath - Lustleigh Fault Zone (SLFZ) in Devon, SW England. The SLFZ is one of the several faults on the Cornubian Peninsula and may be linked to Variscan structures rejuvenated in Palaeogene times. The bulk of the basins' fill consists of clays, silts, lignites and sands of Palaeogene age, comparable to the Lough Neagh Basin (Northern Ireland), which is also thought to be part of the SLFZ. The greater part of the British Isles was a land area throughout the Palaeogene. The basin-fills therefore, provide rare, potentially expanded sections through the Palaeocene Eocene Thermal Maximum (PETM), and the Eocene-Oligocene (Oi-1) cooling event in the U.K. Facies analysis has been undertaken on sediments of the Petrockstow and Bovey basins in order to provide a tectonic and palaeoenvironmental context for palaeoclimate reconstructions using palynology, organic geochemistry Methylation Branched Tetraethers/Cyclisation Branched Tetraethers and carbon isotope analyses which have identified the Carbon Isotope Excursion (CIE) associated with the PETM. The following lithofacies types from two boreholes from the Petrockstow Basin (boreholes 1A and 1B) and from outcrop exposed in the Bovey Basin. The lithofacies identified are (a): Silty clay; (b): Red mottled and sideritic clay; (c): laminated silty clay; (d): Minor sand and gravel; (e): Major coarse sand and granules and (f): Lignite. Our new facies model involves: firstly Sand filled fluvial channels, secondly a lake with ready supply of organic debris, and thirdly a lake prone to drying-out. The abrupt transition from sand filled fluvial channels to Lake Facies is coincident with the recognition of the CIE. The possible effect of the Oi-1 glaciation may be linked to the third phase of a lake prone to drying-out facies which is ambiguous in the Bovey Basin. Repeated sub aerial exposure suggests that the lakes present in both

  20. A review of tectonics and sedimentation in a forearc setting: Hellenic Thrace Basin, North Aegean Sea and Northern Greece

    NASA Astrophysics Data System (ADS)

    Maravelis, A. G.; Boutelier, D.; Catuneanu, O.; Seymour, K. St.; Zelilidis, A.

    2016-04-01

    Exposure of the forearc region of the North Aegean Sea, Greece, offers insight into evolving convergent margins. The sedimentary fill of the Thrace Basin during the Late Eocene to Oligocene time provides a record of subduction-driven processes, such as growth of magmatic arcs and construction of accretionary complexes. This large sediment repository received sediment from two sources. The southern (outboard) basin margin reflects the active influence of the exhumed accretionary prism (e.g. Pindic Cordillera or Biga peninsula), while the northern (inboard) margin records the effect of the magmatic arc in the Rhodope region. The forearc basin sedimentary fills shoal upward into shallow-marine strata but are dominated mainly by deep-marine facies. The depositional trend and stacking pattern are dominated by progradational patterns. This trend, which is observed in both basin margins, is related to tectonic deformation rather than sea-level fluctuations. Additional evidence for this tectonic uplift comes from the backstripping analysis. The accretionary complex provided material into the forearc basin. This material was transported northeast and formed a sand-rich turbidity system that evolved upslope into shallow-marine deposits. Stratigraphic data indicate that this turbidity system exhibits a successive landward (inboard) migration of the depocenter. Provenance data utilizing sandstone petrography, conglomerate clast composition, and bulk-rock geochemistry suggest that this system reflects an increased influx of mafic material into the basin. Volcanic arc-derived material was transported south and east and accumulated in deep-marine settings. Both stratigraphic and provenance data indicate a seaward (outboard) migration of the basin depocenter and a significant increase in felsic detritus into the forearc.

  1. Crustal fluid and ash alteration impacts on the biosphere of Shikoku Basin sediments, Nankai Trough, Japan.

    PubMed

    Torres, M E; Cox, T; Hong, W-L; McManus, J; Sample, J C; Destrigneville, C; Gan, H M; Gan, H Y; Moreau, J W

    2015-11-01

    We present data from sediment cores collected from IODP Site C0012 in the Shikoku Basin. Our site lies at the Nankai Trough, just prior to subduction of the 19 Ma Philippine Sea plate. Our data indicate that the sedimentary package is undergoing multiple routes of electron transport and that these differing pathways for oxidant supply generate a complex array of metabolic routes and microbial communities involved in carbon cycling. Numerical simulations matched to pore water data document that Ca(2+) and Cl(1-) are largely supplied via diffusion from a high-salinity (44.5 psu) basement fluid, which supports the presence of halophile Archean communities within the deep sedimentary package that are not observed in shallow sediments. Sulfate supply from basement supports anaerobic oxidation of methane (AOM) at a rate of ~0.2 pmol cm(-3) day(-1) at ~400 mbsf. We also note the disappearance of δ-Proteobacteria at 434 mbsf, coincident with the maximum in methane concentration, and their reappearance at 463 mbsf, coinciding with the observed deeper increase in sulfate concentration toward the basement. We did not, however, find ANME representatives in any of the samples analyzed (from 340 to 463 mbsf). The lack of ANME may be due to an overshadowing effect from the more dominant archaeal phylotypes or may indicate involvement of unknown groups of archaea in AOM (i.e., unclassified Euryarchaeota). In addition to the supply of sulfate from a basement aquifer, the deep biosphere at this site is also influenced by an elevated supply of reactive iron (up to 143 μmol g(-1)) and manganese (up to 20 μmol g(-1)). The effect of these metal oxides on the sulfur cycle is inferred from an accompanying sulfur isotope fractionation much smaller than expected from traditional sulfate-reducing pathways. The detection of the manganese- and iron-reducer γ-Proteobacteria Alteromonas at 367 mbsf is consistent with these geochemical inferences. PMID:26081483

  2. Effects of sediment removal on vegetation communities in Rainwater Basin playa wetlands.

    PubMed

    Beas, Benjamin J; Smith, Loren M; LaGrange, Theodore G; Stutheit, Randy

    2013-10-15

    Sedimentation from cultivated agricultural land use has altered the natural hydrologic regimes of depressional wetlands in the Great Plains. These alterations can negatively affect native wetland plant communities. Our objective was to determine if restored wetlands are developing plant communities similar to reference wetland conditions following hydrologic restoration. For this study, hydrology was restored via sediment removal. Thirty-four playa wetlands in reference, restored, and agricultural condition within the Rainwater Basin Region of Nebraska were sampled in 2008 and 2009. In 2008, reference and restored wetlands had higher species richness and more native, annual, and perennial species than agricultural wetlands. Restored wetlands had similar exotic species richness compared to reference and agricultural wetlands; however, reference wetlands contained more than agricultural wetlands. Restored wetlands proportion of exotics was 3.5 and 2 times less than agricultural wetlands and reference wetlands respectively. In 2009, reference and restored wetlands had higher species richness, more perennial species, and more native species than agricultural wetlands. Restored wetlands contained a greater number and proportion of annuals than reference and agricultural wetlands. Canonical Correspondence Analysis showed that reference, restored, and agricultural wetlands are dominated by different plant species and guilds. Restored wetland plant communities do not appear to be acting as intermediates between reference and agricultural wetland conditions or on a trajectory to reach reference conditions. This may be attributed to differing seed bank communities between reference and restored wetlands, dispersal limitations of perennial plant guilds associated with reference wetland conditions, and/or management activities may be preventing restored wetlands from reaching reference status.

  3. Crustal fluid and ash alteration impacts on the biosphere of Shikoku Basin sediments, Nankai Trough, Japan.

    PubMed

    Torres, M E; Cox, T; Hong, W-L; McManus, J; Sample, J C; Destrigneville, C; Gan, H M; Gan, H Y; Moreau, J W

    2015-11-01

    We present data from sediment cores collected from IODP Site C0012 in the Shikoku Basin. Our site lies at the Nankai Trough, just prior to subduction of the 19 Ma Philippine Sea plate. Our data indicate that the sedimentary package is undergoing multiple routes of electron transport and that these differing pathways for oxidant supply generate a complex array of metabolic routes and microbial communities involved in carbon cycling. Numerical simulations matched to pore water data document that Ca(2+) and Cl(1-) are largely supplied via diffusion from a high-salinity (44.5 psu) basement fluid, which supports the presence of halophile Archean communities within the deep sedimentary package that are not observed in shallow sediments. Sulfate supply from basement supports anaerobic oxidation of methane (AOM) at a rate of ~0.2 pmol cm(-3) day(-1) at ~400 mbsf. We also note the disappearance of δ-Proteobacteria at 434 mbsf, coincident with the maximum in methane concentration, and their reappearance at 463 mbsf, coinciding with the observed deeper increase in sulfate concentration toward the basement. We did not, however, find ANME representatives in any of the samples analyzed (from 340 to 463 mbsf). The lack of ANME may be due to an overshadowing effect from the more dominant archaeal phylotypes or may indicate involvement of unknown groups of archaea in AOM (i.e., unclassified Euryarchaeota). In addition to the supply of sulfate from a basement aquifer, the deep biosphere at this site is also influenced by an elevated supply of reactive iron (up to 143 μmol g(-1)) and manganese (up to 20 μmol g(-1)). The effect of these metal oxides on the sulfur cycle is inferred from an accompanying sulfur isotope fractionation much smaller than expected from traditional sulfate-reducing pathways. The detection of the manganese- and iron-reducer γ-Proteobacteria Alteromonas at 367 mbsf is consistent with these geochemical inferences.

  4. The record of India-Asia collision preserved in Tethyan ocean basin sediments.

    NASA Astrophysics Data System (ADS)

    Najman, Yani; Jenks, Dan; Godin, Laurent; Boudagher-Fadel, Marcelle; Bown, Paul; Horstwood, Matt; Garzanti, Eduardo; Bracialli, Laura; Millar, Ian

    2015-04-01

    The timing of India-Asia collision is critical to the understanding of crustal deformation processes, since, for example, it impacts on calculations regarding the amount of convergence that needs to be accommodated by various mechanisms. In this research we use sediments originally deposited in the Tethyan ocean basin and now preserved in the Himalayan orogeny to constrain the timing of collision. In the NW Himalaya, a number of workers have proposed a ca 55-50 Ma age for collision along the Indus suture zone which separates India from the Kohistan-Ladakh Intraoceanic Island arc (KLA) to the north. This is based on a number of factors including the age of youngest marine sediments in the Indus suture (e.g. Green et al. 2008), age of eclogites indicative of onset of Indian continental subduction (e.g. de Sigoyer et al. 2000), and first evidence of detritus from north of the suture zone deposited on the Indian plate (e.g. Clift et al. 2002). Such evidence can be interpreted as documenting the age of India-Asia collision if one takes the KLA to have collided with the Asian plate prior to its collision with India (e.g. Petterson 2010 and refs therein). However, an increasing number of workers propose that the KLA collided with Asia subsequent to its earlier collision with India, dated variously at 85 Ma (Chatterjee et al. 2013), 61 Ma (Khan et al. 2009) and 50 Ma (Bouilhol et al. 2013). This, plus the questioning of earlier provenance work (Clift et al. 2002) regarding the validity of their data for constraining timing of earliest arrival of material north of the suture deposited on the Indian plate (Henderson et al. 2011) suggests that the time is right for a reappraisal of this topic. We use a provenance-based approach here, using combined U-Pb and Hf on detrital zircons from Tethyan ocean basin sediments, along with petrography and biostratigraphy, to identify first arrival of material from north of the Indian plate to arrive on the Indian continent, to constrain

  5. Dioxins and furans in bed sediment and fish tissue of the Willamette Basin, Oregon, 1992-95

    USGS Publications Warehouse

    Bonn, B.A.

    1997-01-01

    Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) are related compounds that are of interest primarily because of their potential toxicity. They are considered carcinogens and have been implicated as hormone disrupters. An occurrence and distribution study of these compounds in the Willamette Basin, Oregon, was done by the U.S. Geological Survey in 1992- 1995. Bed sediment samples were collected at 22 sites, and fish tissue samples were collected from 8 sites. Samples were analyzed for 10 tetra- through octa- congener class totals and for 17 individual 2,3,7,8-substituted congeners. PCDD/Fs were found in bed sediment and fish tissue throughout the basin, including samples from the most remote forested sites. PCDD/F concentrations in bed sediment at most sites in agricultural and forested areas were similar to those at reference sites worldwide and are probably background concentrations due to atmospheric deposition. The highest concentrations in bed sediment were found at sites where industrial or urban inputs were likely. Potential toxicity at these sites (as measured by toxicity equivalents concentration) was high enough to be associated with increased risk to sensitive wildlife. From 30-60 percent of the toxicity equivalents concentration in bed sediment was due to hepta- and octa- congeners. The most toxic congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), was detected at only 6 of 22 sites. Compared to bed sediment from the same site, fish tissue usually had a lower total PCDD/F concentration, but contained a higher proportion of the most toxic congeners, such as 2,3,7,8-TCDD and 2,3,7,8-tetrachlorodibenzofuran. Because of these differences, toxicity equivalents concentrations in fish were higher than those in bed sediment from the same site at half of the sites where both media were analyzed.

  6. Organochlorine compounds in bed sediment and fish tissue in the South Platte River Basin, USA, 1992-1993

    USGS Publications Warehouse

    Tate, C.M.; Heiny, J.S.

    1996-01-01

    Bed-sediment and fish-tissue samples were collected in the South Platte River Basin to determine the occurrence and distribution of organochlorine compounds in the basin. During August-November 1992 and August 1993, bed sediment (23 sites) and fish tissue (subset of 19 sites) were sampled and analyzed for 32 organochlorine compounds in bed sediment and 27 compounds in fish tissue. More types of organochlorine compounds were detected in fish tissue than in bed sediment. Total DDT, p,p???-DDE, o,p???-DDE, p,p???-DDD, total PCS, Dacthal??, dieldrin, cis-chlordane, cis-nonachlor, trans-nonachlor, and p,p???-DDT were detected in fish tissue at >25% of the sites; p,p???-DDE, total DDT, cis-chlordane, and trans-chlordane were detected in bed sediment at >25% of the sites. Organochlorine concentrations in bed sediment and fish tissue were related to land-use settings. Few organochlorine compounds were detected at minimally impacted sites located in rangeland, forest, and built-up land-use settings. Chlordane-related compounds and p,p???-methoxychlor in bed sediment and fish tissue, endrin in fish tissue, and endosulfan I in bed sediment were associated with urban and mixed (urban and agricultural) sites. Dacthal?? in bed sediment and fish tissue was associated with agricultural sites. The compounds HCB, ??-HCH, PCA, and toxaphene were detected only at mixed land-use sites. Although DDT and DDT-metabolites, dieldrin, and total PCB were detected in urban, mixed, and agricultural land-use settings, highest mean concentrations were detected at mixed land-use sites. Mixed land-use sites had the greatest number of organochlorine compounds detected in fish tissue, whereas urban and mixed sites had the greatest number of organochlorine compounds detected in bed sediment. Measuring concentrations of organochlorine compounds in bed sediment and fish tissue at the same site offers a more complete picture of the persistence of organochlorine compounds in the environment and their

  7. Sediment loads, discharges, and yields in the East Branch Mahoning Creek basin, Clearfield and Jefferson counties, Pennsylvania, June 1979 through September 1981

    USGS Publications Warehouse

    Loper, C.A.; Wetzel, K.L.

    1988-01-01

    Rainfall, streamflow, and sediment discharge data were collected from the East Branch Mahoning Creek basin from June 1979 through September 1981 to evaluate sediment discharges from an area in which erosion and sediment controls were being used on surface mined areas. Sediment yields from the basin averaged 144 tons/sq mi/year. During the study, 9,570 tons of sediment were transported from the East Branch Mahoning Creek basin. Increased monthly suspended-sediment loads were found after July 1980 when mined-area reclamation was accelerated. Beaver Run near Troutville discharged 576 tons of sediment, which was 7% of the load transported from the basin from December 1979 through September 1981. Turbidity and suspended-sediment concentration follow a linear relation throughout the range of measured values. Using this relation and the frequency distribution of suspended-sediment concentrations, the estimated turbidity levels in the stream were equal to or greater than 30 Nephelometric Turbidity Units (the level at which the streams become unusable as a public water source) approximately 15% of the time during the study. (USGS)

  8. Multiple evidence for methylotrophic methanogenesis as the dominant methanogenic pathway in hypersaline sediments from the Orca Basin, Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Zhuang, Guang-Chao; Elling, Felix J.; Nigro, Lisa M.; Samarkin, Vladimir; Joye, Samantha B.; Teske, Andreas; Hinrichs, Kai-Uwe

    2016-08-01

    Among the most extreme habitats on Earth, dark, deep, anoxic brines host unique microbial ecosystems that remain largely unexplored. As the terminal step of anaerobic degradation of organic matter, methanogenesis is a potentially significant but poorly constrained process in deep-sea hypersaline environments. We combined biogeochemical and phylogenetic analyses with incubation experiments to unravel the origin of methane in the hypersaline sediments of Orca Basin in the northern Gulf of Mexico. Substantial concentrations of methane, up to 3.4 mM, coexisted with high concentrations of sulfate from 16 to 43 mM in two sediment cores retrieved from the northern and southern parts of Orca Basin. The strong depletion of 13C in methane (-77‰ to -89‰) points towards a biological source. While low concentrations of competitive substrates limited the significance of hydrogenotrophic and acetoclastic methanogenesis, the presence of non-competitive methylated substrates (methanol, trimethylamine, dimethyl sulfide, dimethylsulfoniopropionate) supported the potential for methane generation through methylotrophic methanogenesis. Thermodynamic calculations demonstrated that hydrogenotrophic and acetoclastic methanogenesis were unlikely to occur under in situ conditions, while methylotrophic methanogenesis from a variety of substrates was highly favorable. Likewise, carbon isotope relationships between methylated substrates and methane suggested methylotrophic methanogenesis was the major source of methane. Stable and radio-isotope tracer experiments with 13C-labeled bicarbonate, acetate and methanol and 14C-labeled methylamine indicated that methylotrophic methanogenesis was the predominant methanogenic pathway. Based on 16S rRNA gene sequences, halophilic methylotrophic methanogens related to the genus Methanohalophilus dominated the benthic archaeal community in the northern basin and also occurred in the southern basin. High abundances of methanogen lipid biomarkers such as

  9. Characteristics of road sediment fractionated particles captured from paved surfaces, surface run-off and detention basins.

    PubMed

    Kayhanian, M; McKenzie, E R; Leatherbarrow, J E; Young, T M

    2012-11-15

    This study presents the results of evaluating changes in properties of road sediment fractionated particles at the source (dry pavement), during transport (highway runoff) and after deposition (dry detention basin). A total of 38 solid particle samples were collected from paved surface, highway runoff, and from three locations within detention basins. Each sample was size-fractionated ranging from 38 μm to 1000 μm. Key results were that: (i) less than 2% of total particle mass in four vacuumed solid samples was associated with the <38 μm fraction compared to 47 to 82% in centrifuged highway runoff samples and 25% for detention basin sediments, (ii) based on number concentrations more than 90% of particles from all sources were smaller than 38 μm, (iii) the densities of fractionated particles were generally within the range from 1.5 to 2.2g/cm(3); (iv) all collected particles were predicted to resist aggregation in solution with a typical measure of surface potential, the zeta potential, typically ranging from -15 to -30 mV, (v) metal concentrations increased with decreasing particle size for vacuumed samples from the highway shoulder and parking lot, however, size dependent trends in metal concentrations were less apparent in centrifuged highway runoff samples and detention basin sediment samples; (vi) the distributions of metal mass across sieved size fractions generally followed patterns of particle mass distribution in which less than 10% of the total Cu, Pb, and Zn mass was associated with particles <38 μm; (vii) metal mass distributions tended toward increasing metal fractions in finer particle fractions along a gradient from the inlet to the outlet of the detention basins; and (viii) individual particle morphology (1 < d(p) < 10 μm) showed that particles were not smooth or spherical, clearly deviating from the assumptions typically used in estimating particle settling velocities using Stokes' Law.

  10. SeamountFlux: Pore water geochemistry and sediment characteristics (Guatemala Basin, East Pacific)

    NASA Astrophysics Data System (ADS)

    Pichler, T.; Poonchai, W.; Schmidt-Schierhorn, F.; Villinger, H. W.

    2011-12-01

    The scientific goal of the project "SeamountFlux" is to study a process, which can possibly contribute significantly to large scale cooling of the oceanic crust. The focus of the study is to investigate the exchange of matter and energy between the ocean and the upper young oceanic crust in the vicinity of unexplained circular depressions in the sedimentary cover, which are widely spread in the equatorial Pacific. A possible model for the formation of these so-called "hydrothermal pits" is the dissolution of calcium carbonate (CaCO3) minerals by upward flowing warm fluids, which are under-saturated in CaCO3. Seamounts are suspected to act as an entrance point for cold seawater, which then equilibrates with the basaltic oceanic crust prior to exiting through the pits. Such a process should affect the thermal structure in and around the pits as well as the geochemistry of the pore water. During cruise SO207 (June/July 2010 on the German RV Sonne) in the vicinity of ODP/IODP Site 1256 and ODP site 844 (Guatemala Basin, eastern equatorial Pacific) we collected 24 gravity cores varying in length between 3.3 m an