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We investigated sediment flux across an ice-dominated, high latitude continental margin, using cores from the East Greenland Shelf (ca. 68 deg N). Density, weight percentages of the various sediment components, and sediment/age re...
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We investigated sediment flux across an ice-dominated, high latitude continental margin, using cores from the East Greenland Shelf (ca. 68 deg N). Density, weight percentages of the various sediment components, and sediment/age relations (AMS C- 14 dates) were investigated from cores collected 1988 and 1990. High-resolution DTS Huntec surveys indicated 10-20 m of acoustically transparent sediment. Maximum core length was 3 m and most of the gravity cores were between 1-2 m. The radiocarbon assays show that basal core sediments date between ca. 9,000 and 14,500 BP. The acoustic characteristics, the low dry volume densities (ca. 600 kg/m3 and the faunal and floral assemblages suggest ice-distal conditions between ca. 14,500 and the present. Net sediment flux in the Kangerdlugssuaq Trough during the last 14,500 years has been low; this might be explained by either (1) cold-based glaciological conditions of the East Greenland ice sheet; and/or (2) efficient sediment trap(s) lying along the inner shelf/fjords of East Greenland.
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In Alaskan fiords, sedimentation rates are high; during a glacial advance fiord-basin sediments are transported to the ice front to form a shoal which reduces the calving rate. Thus, during successive glacial cycles sediment is in...
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In Alaskan fiords, sedimentation rates are high; during a glacial advance fiord-basin sediments are transported to the ice front to form a shoal which reduces the calving rate. Thus, during successive glacial cycles sediment is initially stored and then removed from fiord basins. In the fiords of eastern Baffin Island sedimentation rates are, and were, much lower (<1000 Kg/Sq m ka), and fiord-basin fills may span several glacial cycles. This hypothesis is in keeping with the relatively low sedimentation rates on the adjacent shelf (50 to 500 Kg/sq m ka) and deep-sea plain (< or 50 Kg/Sq m ka). The advance of outlet glaciers through these arctic fiords may be explained by the in situ growth of a floating ice-shelf, grounded at the mouth of the fiord. The extent of late Foxe Glaciation in McBeth and Itirbilung fiords can be delimited by raised marine deltas (50-85 m asl) with C14 dates on in situ shells and whalebone of >54 ka. Holocene raised beaches are lower and date <10 ka. These data, plus the absence of lodgements tills in raised marine sections along the outer coast, make it difficult to extend grounded ice onto the shelf during the 18 ka global maximum. Piston cores from Tingin, Itirbilung and McBeth fiords vary between 4 and 11 m in length, but sample only a portion of the total basin-fills. Calculations of sediment accumulation rates are not trivial because of problems in the C14 dating of total organics and questions on the true age and sample depth of the tops of the piston cores. (edc)
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Piston cores from fiords along the eastern margin of Baffin Island, N>W>T> are being studied in order to compute variations in sediment flux on time scales of decades to thousands of years. Radiocarbon dates indicate that the sedi...
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Piston cores from fiords along the eastern margin of Baffin Island, N>W>T> are being studied in order to compute variations in sediment flux on time scales of decades to thousands of years. Radiocarbon dates indicate that the sedimentation rates in outer basins range, on average, between 20-50cm/THAT'S NUMBER: 1 (NOT ALPHA)ka. The cores extend back to ca. 10 ka, or earlier, and provide possible analogs for conditions around the present day Greenland Ice Sheet. Grain size, grain shape and mineralogical studies are being carried out in order to evaluate down fiord variations in sediment source and sedimentation processes.
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To receive advice on its Arctic research programs and how they can interact with and complement those of other agencies, the Department of Energy (DOE) asked the Polar Research Board of the National Research Council to assist it i...
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To receive advice on its Arctic research programs and how they can interact with and complement those of other agencies, the Department of Energy (DOE) asked the Polar Research Board of the National Research Council to assist it in formulating an Arctic terrestrial environmental research program. As a result, the Committee to Evaluate DOE's Arctic Terrestrial Environmental Research Programs was formed and held two meetings and a workshop. The Committee issued in early 1982 a two-volume report, Arctic Terrestrial Environmental Research Programs of the Office of Energy Research, Department of Energy: Evaluation and Recommendations'' and ''Appendix A'': Terrestrial Environmental Research in Alaska During 1980-1981. The report includes recommendations for a coherent and integrated program of Arctic terrestrial environmental research consistent with DOE interests that might be used by the DOE Ecological Research Division in developing long-range research objectives and plans for their implementation. The DOE subsequently requested that the Committee follow up its initial recommendations by identifying the specific components of an Arctic terrestrial environmmental research program. The resulting plan, which is the subject of this appendix, elaborates on the Committee's earlier recommendations. Contents of this report include: (1) purpose and background; (2) impacts on the environment; (3) approach to research; (4) research priorities; (5) research plan (descriptive background studies, experimental and manipulative studies - riparian ecosystems, impacts of and recovery from disturbances on slopes and from changes in drainage, air pollution, and vegetation removal); (6) research sites; and (7) schedule. (ERA citation 11:020949)
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The objectives include: (1) building a data base of modern surface pollen samples from across the eastern and central Canadian arctic as well as along the North Slope of Alaska; (2) documenting changes in the pollen spectra at a s...
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The objectives include: (1) building a data base of modern surface pollen samples from across the eastern and central Canadian arctic as well as along the North Slope of Alaska; (2) documenting changes in the pollen spectra at a series of peat and lake sites in northern Labrador, Baffin Island, and Keewatin; (3) preparing a series of transfer functions that relate modern climatic data to modern surface pollen spectra and applying the equations to fossil pollen spectra in the eastern Canadian arctic; and (4) discussing the significance of spikes of exotic tree and shrub pollen in high arctic peat and lake samples as paleoclimatic indicators. (ERA citation 08:047535)
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This report discusses how climatic analyses, permafrost temperatures, and geomorphic processes might be used to interpret the influence of a CO sub 2 induced climate change on northern ecosystems. It is based on a series of inform...
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This report discusses how climatic analyses, permafrost temperatures, and geomorphic processes might be used to interpret the influence of a CO sub 2 induced climate change on northern ecosystems. It is based on a series of informal discussions amongst the authors and several specialists conducted over a period of several months in spring 1980, at the request of the Department of Energy - American Association for the Advancement of Science CO sub 2 Project. The report concludes with a generalized research outline for documenting the cause and effect relationships discussed. (ERA citation 07:044623)
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