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

这笔用于探索性研究的小额赠款支持一种地球化学技术的发展，以确定南极洲大陆冰盖冰川侵蚀的开始时间。这项技术从海洋沉积物中沉淀的自生(海水来源)铁锰相中配对了钕(ND)和氢(Hf)同位素代用品。这项技术有望成为冰川侵蚀的敏感指标。矿物锆石中含有非放射性成因的HF，只有在冰川侵蚀的同时进行研磨才能释放出来。以前开发这项技术的尝试遇到了困难，因为涉及的氢氟量很少，而且提取困难。PIS已经开发了一种新的化学方案，应该允许他们从散装沉积物中选择性地提取自生氢。如果成功，将从韦德尔海和科尔盖伦高原两个钻心对始新世-渐新世边界进行研究。这一边界被认为是南极洲当前冰盖形成的起点。如果成功，这种方法将使对大陆风化、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感兴趣的科学家受益。这项工作的更广泛影响是开发了一种新的分析技术，这种技术可能会从深层时间记录的角度改善社会对全球气候变化潜力的理解。

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.