globalchange  > 影响、适应和脆弱性
DOI: 10.5194/cp-14-991-2018
Scopus记录号: 2-s2.0-85049727508
论文题名:
Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica - Part 1: Insights from late Oligocene astronomically paced contourite sedimentation
作者: Salabarnada A.; Escutia C.; Röhl U.; Nelson C.H.; McKay R.; Jiménez-Espejo F.J.; Bijl P.K.; Hartman J.D.; Strother S.L.; Salzmann U.; Evangelinos D.; López-Quirós A.; Flores J.A.; Sangiorgi F.; Ikehara M.; Brinkhuis H.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2018
卷: 14, 期:7
起始页码: 991
结束页码: 1014
语种: 英语
Scopus关键词: astronomy ; bottom water ; climate feedback ; continental shelf ; contourite ; glacial deposit ; global climate ; ice sheet ; interglacial ; Ocean Drilling Program ; offshore application ; Oligocene ; paleoceanography ; sedimentation ; Southern Hemisphere ; Antarctic Ice Sheet ; Antarctica ; Atlantic Ocean ; Atlantic Ocean (North) ; East Antarctica ; Ross Sea ; Southern Ocean ; Wilkes Land ; Wilkes Subglacial Basin
英文摘要: Antarctic ice sheet and Southern Ocean paleoceanographic configurations during the late Oligocene are not well resolved. They are however important to understand the influence of high-latitude Southern Hemisphere feedbacks on global climate under CO2 scenarios (between 400 and 750 ppm) projected by the IPCC for this century, assuming unabated CO2 emissions. Sediments recovered by the Integrated Ocean Drilling Program (IODP) at Site U1356, offshore of the Wilkes Land margin in East Antarctica, provide an opportunity to study ice sheet and paleoceanographic configurations during the late Oligocene (26-25 Ma). Our study, based on a combination of sediment facies analysis, magnetic susceptibility, density, and X-ray fluorescence geochemical data, shows that glacial and interglacial sediments are continuously reworked by bottom currents, with maximum velocities occurring during the interglacial periods. Glacial sediments record poorly ventilated, low-oxygenation bottom water conditions, interpreted as resulting from a northward shift of westerly winds and surface oceanic fronts. Interglacial sediments record more oxygenated and ventilated bottom water conditions and strong current velocities, which suggests enhanced mixing of the water masses as a result of a southward shift of the polar front. Intervals with preserved carbonated nannofossils within some of the interglacial facies are interpreted as forming under warmer paleoclimatic conditions when less corrosive warmer northern component water (e.g., North Atlantic sourced deep water) had a greater influence on the site. Spectral analysis on the late Oligocene sediment interval shows that the glacial-interglacial cyclicity and related displacements of the Southern Ocean frontal systems between 26 and 25Ma were forced mainly by obliquity. The paucity of iceberg-rafted debris (IRD) throughout the studied interval contrasts with earlier Oligocene and post-Miocene Climate Optimum sections from Site U1356 and with late Oligocene strata from the Ross Sea, which contain IRD and evidence for coastal glaciers and sea ice. These observations, supported by elevated sea surface paleotemperatures, the absence of sea ice, and reconstructions of fossil pollen between 26 and 25 Ma at Site U1356, suggest that open-ocean water conditions prevailed. Combined, this evidence suggests that glaciers or ice caps likely occupied the topographic highs and lowlands of the now marine Wilkes Subglacial Basin (WSB). Unlike today, the continental shelf was not overdeepened and thus ice sheets in the WSB were likely land-based, and marine-based ice sheet expansion was likely limited to coastal regions. © Author(s) 2018.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109548
Appears in Collections:影响、适应和脆弱性
气候变化事实与影响

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作者单位: Instituto Andaluz de Ciencias de la Tierra, CSIC, Univ. de Granada, Armilla, 18100, Spain; MARUM - Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse 8, Bremen, 28359, Germany; Antarctic Research Centre, Victoria University of Wellington, Wellington, 6140, New Zealand; Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, 237-0061, Japan; Department of Earth Sciences, Marine Palynology and Palaeoceanography, Faculty of Geosciences, Laboratory of Palaeobotany and Palynology, Utrecht University, Princetonlaan 8a, Utrecht, 3584 CB, Netherlands; Department of Geography and Environmental Sciences, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST, United Kingdom; Department of Geology, University of Salamanca, Salamanca, 37008, Spain; Center for Advanced Marine Core research, Kochi University, Nankoku, Kochi, 783-8502, Japan; NIOZ, Royal Netherlands Institute for Sea Research, Utrecht University, Landsdiep 4, 'tHorntje, Texel, 1797SZ, Netherlands

Recommended Citation:
Salabarnada A.,Escutia C.,Röhl U.,et al. Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica - Part 1: Insights from late Oligocene astronomically paced contourite sedimentation[J]. Climate of the Past,2018-01-01,14(7)
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