The Stratigraphic Expression of the Onset of Glaciation in Eocene-Oligocene Successions on the Antarctic Continental Margin

南极大陆边缘始新世-渐新世序列中冰川作用起始的地层表现

• 批准号: 1245283
• 负责人: Sandra Passchier
• 金额: $ 11.89万
• 依托单位: Montclair State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1245283&HistoricalAwards=false
• 关键词: Stratigraphic; Expression; Onset; Glaciation; Eocene

Intellectual Merit: This project will investigate glacial advance and retreat of the East Antarctic Ice Sheet through the Eocene-Oligocene transition, a major episode of ice growth. In Prydz Bay, East Antarctica, a 130-170 m thick Eocene-Oligocene transition interval of glaciomarine sediments was cored in drillholes of the Ocean Drilling Program at Sites 739, 742 and 1166. Correlations between the Prydz Bay drillholes have recently been made through well-log and multichannel seismic interpretations. Recent drilling on the Wilkes Land margin of East Antarctica recovered earliest Oligocene sediments overlying a major regional unconformity in two drillholes. The PI will study the lithostratigraphy and weathering history of cores in the five drillholes, to establish a unique Eocene-Oligocene transition record within Antarctic continental margin sediments of glacial advance and retreat cycles, the onset of physical weathering, and glacio-isostasy and self-gravitation processes with implications for the margin architecture, sediment routing, and off-shore sediment dispersal. Cores from the five drillholes will be re-examined through detailed core description using an updated classification scheme, so that lithofacies can be compared between drillholes. Samples will be collected for detailed laser particle size and bulk major element geochemistry via ICP-AES to determine the degree of chemical alteration of the sediments. Phases of major ice growth will be recognized as marker beds of physically eroded sediment and will be correlated to isotopic records documenting Antarctic ice growth offshore in the Southern Ocean. Broader impacts: This project will benefit a large minority undergraduate student population through the availability of up to two paid laboratory internships, a classroom exercise, and the availability of research equipment supported by this award. The project also allows support and training of a graduate student.

学术价值：该项目将研究南极东部冰盖在始新世-渐新世过渡时期的冰川推进和退缩，这是冰生长的一个主要时期。在东南极洲Prydz湾，在海洋钻探计划的739、742和1166钻孔中取芯了130 ~ 170 m厚的始新世-渐新世冰川海洋沉积物过渡段。最近，通过测井和多道地震解释，在Prydz湾钻孔之间建立了相关性。最近在东南极洲威尔克斯陆缘的钻探中，在两个钻孔中发现了覆盖在一个主要区域不整合上的最早渐新世沉积物。PI将研究五个钻孔岩心的岩石地层学和风化历史，在南极大陆边缘沉积物中建立一个独特的始新世-渐新世过渡记录，包括冰川前进和后退旋回、物理风化的开始、冰川均衡和自重力过程，并对边缘结构、沉积物路径和近海沉积物扩散具有指导意义。利用更新后的分类方案，对5个钻孔的岩心进行详细的岩心描述，从而对各钻孔的岩相进行比较。样品将通过ICP-AES收集详细的激光粒度和大块主要元素的地球化学特征，以确定沉积物的化学变化程度。主要冰生长的阶段将被认为是物理侵蚀沉积物的标志层，并将与记录南大洋近海南极冰生长的同位素记录相关联。更广泛的影响：该项目将通过提供最多两次带薪实验室实习、一次课堂练习和本奖项支持的研究设备的可用性，使大量少数民族本科生受益。该项目还允许支持和培训研究生。