Collaborative Research: He and Os isotope investigation of Miocene marine sediments: particulate extraterrestrial matter as a paleoflux tracer

合作研究：中新世海洋沉积物的 He 和 Os 同位素研究：作为古通量示踪剂的颗粒状外星物质

• 批准号: 1060877
• 负责人: Kenneth Farley
• 金额: $ 12.51万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1060877&HistoricalAwards=false
• 关键词: Collaborative; Research; He; Os; isotope

Determining the rates of marine sediment accumulation is critical in reconstructing past changes in productivity and carbon burial, but the ability to reconstruct such flux flux rates over long geologic timescales is been limited by radioactive decay (e.g., 230Thxs) and by variability in the proxy production rate or source (e.g., 4He). This collaborative project, involving researchers from the University of Hawaii at Manoa and the California Institute of Technology, develops the use of extraterrestrial particles in marine sediments as flux proxies, potentially extending scientists? ability to reconstruct changing accumulation rates from tens of thousands of years to hundreds of millions of years. By combining two independent, stable tracers of particulate extraterrestrial matter in marine sediments-- helium (He) and osmium (Os) isotopes-- the researchers will be able to distinguish between changing extraterrestrial flux to Earth and terrestrial focusing of extraterrestrial particles during transport to the seafloor. The method will be applied over a time window of 10 to 4 million years before present, a time period known to encompass an episode of greatly increased extraterrestrial flux to the Earth resulting from collisions in the asteroid belt. The researchers will compare records from a number of different sediment cores from the Pacific Basin, with accumulation rates varying by a factor of more than twenty, to determine whether or not particulate extraterrestrial He is preferentially focused to high sedimentation rate sites relative to Os. Lastly, the researchers will test whether a reliable age model can be developed for Pacific red clays, which would greatly improve the potential of these sediments as paleoceanographic archives. In terms of broader impact, funding supports education and training of a postdoctoral researcher and an undergraduate student and fosters international collaborations. The research will also develop a potentially important new tool that would unlock new potential for studying how important environmental parameters, including productivity and terrestrial aridity, change over long time periods.

确定海洋沉积物积累的速率对于重建过去生产力和碳埋葬的过去变化至关重要，但是重建长期地质时间标准的这种通量通量速率的能力受放射性衰减（例如230THXS）的限制，而限制了代理生产率或源（例如，4He）的能力。这个合作项目涉及夏威夷大学马诺阿大学和加利福尼亚理工学院的研究人员，开发了在海洋沉积物中使用外星颗粒作为通量代理，可能会扩展科学家？能够重建从数万年到数亿年将积累率重建的能力。通过结合海洋沉积物中的两个独立的稳定示踪剂 - 氦（HE）和osmium（OS）同位素 - 研究人员将能够区分地球外星的外星磁通量以及运输到海底期间外星颗粒的地面颗粒的焦点。该方法将在目前的10到400万年的时间窗口中应用，这一时间段已知，该时间段涵盖了小行星带碰撞导致的地球外地球的发作。 研究人员将比较来自太平洋盆地许多不同沉积物核心的记录，积累率的变化为二十以上，以确定他是否优先将相对于OS的高繁殖速率进行了优先聚焦于高泥浆率。最后，研究人员将测试是否可以针对太平洋红粘土开发可靠的年龄模型，这将大大提高这些沉积物作为古复古档案的潜力。在更广泛的影响方面，资金支持博士后研究员的教育和培训，并培养本科生并培养国际合作。这项研究还将开发出一种潜在的重要新工具，该工具将释放新的潜力，以研究重要的环境参数，包括生产力和陆地干燥，在长时间内发生变化。