The Quaternary Glacial History of the Wilkes Land Margin, Antarctica

南极洲威尔克斯陆缘的第四纪冰川历史

• 批准号: 9815085
• 负责人: Detlef Warnke
• 金额: $ 2.97万
• 依托单位: California State University, East Bay Foundation, Inc.
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-15 至 2002-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9815085&HistoricalAwards=false
• 关键词: Quaternary; Glacial; History; Wilkes; Land

This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports research to study existing sediment cores from the Wilkes Land margin (i.e., USNS-Eltanin 1968-1971, US Geological Survey 1984, and Japanese National Oil Corporation 1982-1983 cruises), supplemented by new material that will be collected during a cruise to Wilkes Land in February-March 2000 by the Osservatorio Geofisico Sperimentale (OGS), Trieste, Italy and Antarctic CRC, Hobart, Australia. The objective of the study is to determine how the evolution of the East Antarctic Ice Sheet has affected the deposition of Quaternary sedimentary sequences on the Wilkes Land continental shelf, slope, and rise. The present model of glacial stratigraphy for the Wilkes Land margin indicates that supply of sediment to the shelf, slope and rise is strongly cyclic. During times of glacial maxima, most terrigenous deposition occurs on the outer shelf, slope and rise. During interglacials, most terrigenous deposition occurs on the inner shelf, while the outer shelf, slope and rise receive mainly biogenic and hemipelagic sediment. The most complete record of glacial/interglacial, and smaller scale cycles can thus be obtained by combining the sedimentary record contained on the shelf, slope and rise. The existing sediment cores (up to 11 meters long) will be dated using diatom stratigraphy and magnetostratigraphy. Once sediment cores are dated, sedimentation and accumulation rates will be determined for each depositional environment to determine shifts in depositional centers across the margin. Studies of downcore variations of sedimentary parameters (e.g., siliciclastic vs. biogenic, clast-rich vs. clast-poor intervals, and massive vs. laminated) will be done in order to determine: 1) glacial sedimentary processes which control patterns of sediment distribution and 2) cyclicities in the strata that can help to establish climatic fluctuations related to Antarctic glacial events in the Wilkes Land margin. Study of existing cores will be complemented by preliminary results from shipboard and onshore analyses of cores collected during the 10 February -19 March 2000 OGS - Antarctic CRC cruise. Shipboard analyses include: visual description, determination of physical properties, smear slides and microfossil identification. Cores from the cruise will be stored in the Antarctic CRC Marine Geoscience institute, Hobart, Australia. If appropriate materials can be recovered, and it appropriate reservoir corrections can be established, some samples will be selected for radiocarbon dating using accelerator mass spectrometry techniques on core samples frozen just after collection. Results from this project will be used to help fulfill ODP requirements for "maturation" of the existing ODP proposal for drilling on the Wilkes Land continental margin.This research is expected to provide information that will allow refinement of the existing depositional models and to understand better the glacial/interglacial sedimentation processes and cycles across this margin. This research was developed in response to recent national (NSF-East Antarctic Margin Workshop, Ohio, 1997) and international (ANTIME and ANTOSTRAT, Hobart, 1997) workshops, where the Wilkes Land margin was identified as one of the main targets for multidisciplinary research, including long-term and recent glacial history.

该奖项由极地项目办公室南极地质和地球物理项目提供，支持研究威尔克斯陆缘（即，1968-1971年美国国家科学院-埃尔塔宁号、1984年美国地质调查局和1982-1983年日本国家石油公司的巡航考察），并将补充由意大利的里雅斯特的地质观测所和澳大利亚霍巴特的南极CRC在2000年2月至3月前往威尔克斯地的巡航考察中收集的新材料。这项研究的目的是确定东南极冰盖的演变如何影响威尔克斯大陆架，斜坡和上升的第四纪沉积序列的沉积。威尔克斯陆缘的冰川地层学模型表明，沉积物向陆棚、陆坡和陆坡的供给是强烈循环的。在最盛冰期，大多数陆源沉积物发生在外陆棚、斜坡和高地。在间冰期，大多数陆源沉积物发生在内陆架，而外陆架，斜坡和上升主要接受生物和半远洋沉积。因此，将陆棚、陆坡和海隆的沉积记录结合起来，可以获得最完整的冰期/间冰期和较小规模的旋回记录。现有的沉积物岩心（长达11米）将使用硅藻地层学和磁性地层学进行年代测定。一旦确定了沉积岩芯的年代，将确定每种沉积环境的沉积和积累速率，以确定整个边缘的沉积中心的移动。研究沉积参数的井下变化（例如，硅质岩与生物岩、碎屑丰富与碎屑贫乏的间隔、块状与层状），以确定：1）控制沉积物分布模式的冰川沉积过程; 2）有助于确定与威尔克斯陆缘南极冰川事件有关的气候波动的地层旋回性。对现有岩芯的研究将得到对2000年2月10日至3月19日OGS -南极CRC巡航考察期间收集的岩芯进行船上和岸上分析的初步结果的补充。船上分析包括：视觉描述、物理性质测定、涂片和微体化石鉴定。这次考察的岩芯将存放在澳大利亚霍巴特的南极CRC海洋地球科学研究所。如果可以回收适当的材料，并建立适当的储层校正，将选择一些样品，对采集后立即冻结的岩心样品使用加速器质谱技术进行放射性碳测年。该项目的结果将用于帮助满足ODP对Wilkes Land大陆边缘钻探的现有ODP建议的“成熟”要求。该研究预计将提供信息，使现有沉积模型得以改进，并更好地了解该边缘的冰川/间冰期沉积过程和循环。这项研究是为了响应最近的国家（NSF东南极边缘研讨会，俄亥俄州，1997年）和国际（ANTIME和ANTOSTRAT，霍巴特，1997年）研讨会，其中威尔克斯地边缘被确定为多学科研究，包括长期和最近的冰川历史的主要目标之一。