SGER: Development of the Paired Authigenic Neodymium-Hafnium Isotope Weathering Tracer From Marine Sediments in the Circum Antarctic Realm

SGER：从环南极地区海洋沉积物中开发配对自生钕铪同位素风化示踪剂

• 批准号: 0548918
• 负责人: Christina-Maria van de Flierdt
• 金额: $ 7万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0548918&HistoricalAwards=false
• 关键词: SGER; Development; Paired; Authigenic; Neodymium

This Small Grant for Exploratory Research supports development of a geochemical technique to time the onset of glacial erosion from Antarctica's continental ice sheets. The technique pairs neodymium (Nd) and hafnium (Hf) isotope proxies from the authigenic (seawater-derived) ferromanganese phase precipitated in marine sediments. This technique promises to be a sensitive indicator of glacial erosion. Non-radiogenic Hf is contained in the mineral zircon, which can only be released by the abrasive grinding that accompanies glacial erosion. Previous attempts to develop this technique encountered difficulty due to the minute amounts of Hf involved and the difficulty in its extraction. The PIs have developed a new chemical protocol that should allow them to selectively extract authigenic Hf from bulk sediments. If successful, studies of the Eocene-Oligocene boundary from two drill cores the Weddell Sea and Kerguelen Plateau will be carried out. This boundary is considered the initiation point for formation of Antarctica's current ice sheets. If successful, this method will benefit scientists with interests as diverse as continental weathering, ocean circulation, Cenozoic paleoceanography and paleoclimate, and Antarctic geology. The broader impacts of this work are development of a new analytical technique that may improve society's understanding of the potential for global climate change from the perspective of the deep time record.

这项探索性研究小额赠款支持地球化学技术的发展，以确定南极洲大陆冰盖冰川侵蚀开始的时间。该技术将来自海洋沉积物中自生（海水来源）锰铁相沉淀的钕（Nd）和铪（Hf）同位素代用物配对。这项技术有望成为冰川侵蚀的敏感指标。锆石中含有非放射性成因的Hf，只能通过伴随冰川侵蚀的磨料研磨释放出来。由于涉及微量的Hf和提取的困难，以前开发这种技术的尝试遇到了困难。pi已经开发了一种新的化学方案，应该允许他们有选择地从大块沉积物中提取自生Hf。如果成功，将利用威德尔海和克格伦高原两个岩心进行始新世-渐新世界线研究。这个边界被认为是目前南极洲冰盖形成的起始点。如果成功，这种方法将使大陆风化、海洋环流、新生代古海洋学和古气候以及南极地质学等领域的科学家受益。这项工作的更广泛的影响是开发了一种新的分析技术，可以从深时间记录的角度提高社会对全球气候变化潜力的理解。