The Record of Antarctic Environment Preserved in Deep Sea Sediments: Critical Times of Climate Change

深海沉积物中保存的南极环境记录：气候变化的关键时期

• 批准号: 9527067
• 负责人: David Rea
• 金额: $ 22.53万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-02-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9527067&HistoricalAwards=false
• 关键词: Record; Antarctic; Environment; Preserved; Deep

Rea OPP 9527067 Abstract This award supports a project to define the paleoclimatic variability during times of important climate change on Antarctica, in the latest Cretaceous and Paleocene, late Eocene and early Oligocene, and the early Pliocene. Preliminary data suggest that the Maastrichtian and possibly Paleocene environment of Antarctica was dry enough to permit generation of sufficient dust to form an important component of the sediments surrounding the continent. This research will determine if and when this semi-arid climate did exist on Antarctica and when it was superseded by more moist conditions. The transition to fluvial and hemipelagic dominated erosional processes may shed light on the initial formation of glaciers in the Antarctic hinterland. At the time of the Eocene/Oligocene boundary, changing sediment accumulation rates and the relative proportions of hemipelagic and ice-rafted material will provide information on when the Antarctic ice sheet became well-established, effectively shutting off the supply of fluvial sediment to the Southern Ocean. And finally, any significant change in the ice sheet configuration during the early Pliocene should be readily observable in the concomitant changes in the nature and rates of terrigenous sedimentation. To accomplish these goals, this project will examine the terrigenous component of deep sea sediments of the Southern Ocean. These materials contain a dual record of the environment of Antarctica and of the sedimentary transport processes. Techniques of mineral grain extraction, grain-size analysis, magnetic fabric determination, geochemical characterization, and flux calculation, all of which have proven diagnostic in the interpretation of paleoclimatic and paleoceanographic conditions, will be applied within this project to unravel the history of environmental change on the Antarctic continent.

Rea 9527067 摘要该奖项支持一个项目，以确定在南极洲的重要气候变化时期，在最新的白垩纪和古新世，始新世晚期和渐新世早期，上新世早期的古气候变化。 初步数据表明，南极洲的马斯特里赫特时期和可能的古新世环境足够干燥，可以产生足够的尘埃，形成大陆周围沉积物的重要组成部分。 这项研究将确定这种半干旱气候是否以及何时在南极洲存在，以及何时被更潮湿的条件所取代。 过渡到河流和半远洋为主的侵蚀过程可能揭示了在南极内陆冰川的最初形成。 在始新世/渐新世界线时，不断变化的沉积物积累速度以及半远洋和冰筏物质的相对比例将提供关于南极冰盖何时形成的信息，从而有效地切断了向南大洋提供河流沉积物的供应。最后，在上新世早期，冰盖结构的任何重大变化都应该很容易在陆源沉积的性质和速率的伴随变化中观察到。 为实现这些目标，该项目将研究南大洋深海沉积物的陆源成分。 这些材料包含了南极洲环境和沉积迁移过程的双重记录。 矿物颗粒提取、粒度分析、磁组构测定、地球化学表征和通量计算等技术都已证明在解释古气候和古海洋条件方面具有诊断作用，将在本项目中应用这些技术，以揭示南极大陆环境变化的历史。