IPY: SASSI Mooring Array in Western Antarctica Peninsula

摘要本项目研究南极德雷克海峡的开通与南极冰盖形成的关系。它的目标是回答这个问题：是什么推动了3400万年前从温室世界到冰窖世界的转变？是南极与南美洲分离引起的南大洋环流的变化，还是大气中二氧化碳含量减少等全球性影响？这项研究通过在南美洲和南极洲的实地工作以及海洋钻探计划之前收集的海洋沉积物岩心的新工作来限制事件和时间。它还包括一个广泛的、多学科的分析项目。沉积物及其来源的成分分析将与(U-Th)/He、裂变径迹和Ar-Ar热时计相结合，以约束德雷克海峡边界大陆地壳的隆起和运动。在海洋沉积物岩心中发现的化石鱼牙齿的放射性成因同位素研究将用于追踪太平洋海水进入大西洋的情况。对有孔虫的氧同位素和痕量金属测量将提供关于冰体积变化的时间和幅度的额外信息。更广泛的影响包括研究生和本科教育；通过博物馆展览和演讲向公众宣传，并与阿根廷、乌克兰、英国和德国的科学家开展国际合作。该项目得到了美国国家科学基金会国际极地年（IPY）研究重点领域“了解极地地区的环境变化”的支持。该项目也是IPY板块和盖茨计划（IPY项目#77）的关键组成部分，该计划的重点是确定构造门户在引发极地环境变化中的作用。

AbstractThis project studies the relationship between opening of the Drake Passage and formation of the Antarctic ice sheet. Its goal is to answer the question: What drove the transition from a greenhouse to icehouse world thirty-four million years ago? Was it changes in circulation of the Southern Ocean caused by the separation of Antarctica from South America or was it a global effect such as decreasing atmospheric CO2 content? This study constrains the events and timing through fieldwork in South America and Antarctica and new work on marine sediment cores previously collected by the Ocean Drilling Program. It also involves an extensive, multidisciplinary analytical program. Compositional analyses of sediments and their sources will be combined with (U-Th)/He, fission-track, and Ar-Ar thermochronometry to constrain uplift and motion of the continental crust bounding the Drake Passage. Radiogenic isotope studies of fossil fish teeth found in marine sediment cores will be used to trace penetration of Pacific seawater into the Atlantic. Oxygen isotope and trace metal measurements on foraminifera will provide additional information on the timing and magnitude of ice volume changes. The broader impacts include graduate and undergraduate education; outreach to the general public through museum exhibits and presentations, and international collaboration with scientists from Argentina, Ukraine, UK and Germany. The project is supported under NSF's International Polar Year (IPY) research emphasis area on "Understanding Environmental Change in Polar Regions". This project is also a key component of the IPY Plates & Gates initiative (IPY Project #77), focused on determining the role of tectonic gateways in instigating polar environmental change.