What are the sources and mechanisms of iron enrichments during oceanic anoxic event 2? - Evidence from iron stable isotopes

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。本项目将通过对北大西洋原始海域及西部内陆海道（包括DSDP和ODP海域）沉积岩心的总铁同位素（d56Fe）分析，研究海洋缺氧事件II （OAEII, ~94 Ma）的古地质历史。OAEII沉积物的特征是有机碳（OC）浓度高，这可能是由于1)全球缺氧条件增加导致OC保存增加，或2)表层海洋生产力增加。铁对OAEII期间海洋生产力和整体碳循环的影响是本研究的主要目的。为此，本研究将研究热液输入的含氧沉积物中铁的相对输入量与陆架沉积物中铁的相对输入量，陆架沉积物中铁的d56Fe值应明显低于热液来源。OAEII含氧沉积物中沉积铁的d56Fe值和FeT/Al比值将反映热液源的相对贡献。本研究将试图限制OAEII期间海洋中铁的总体质量平衡，从而扩大铁同位素分析在古环境评估中的应用。更广泛的影响：这项研究支持了一名本科生、一名博士后和一名早期职业女性科学家。作为罗格斯大学海洋科学教育卓越中心的一部分，PI将与该中心合作？将研究结果纳入针对K-12教师、K -16学生和沿海管理人员的在线教育材料。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This project will investigate the paleo-geological history of Ocean Anoxic Event II (OAEII, ~94 Ma) by iron isotopic analyses (d56Fe) of total iron in archived sediment cores from the proto North Atlantic and bordering Western Interior Seaway, including several from DSDP and ODP. OAEII sediments are characterized by concentrations of high organic carbon (OC) which might have resulted either from 1) increased preservation of OC resulting from more anoxic conditions globally, or 2) increased surface ocean productivity. The effects of iron on ocean productivity and the overall carbon cycle during OAEII is a major aim of this research. To this end, the research will investigate the relative inputs of Fe to euxinic sediments from hydrothermal inputs versus that remobilized from shelf sediments that should carry a distinctly lower d56Fe value than the hydrothermal source. The d56Fe values and FeT/Al ratios of sedimentary iron in euxinic sediments of OAEII will reflect the relative contribution from hydrothermal sources. This research will try to constrain the overall mass balance of iron in the ocean during OAEII and thus expand the use of Fe isotopic analyses for paleo-environmental assessment.Broader impacts: The research supports an undergraduate student, a postdoc, and an early career female scientist. As part of the Center for Ocean Science Education Excellence at Rutgers University, the PI will work with the Center?s Director to incorporate the research results into online educational materials directed at K-12 teachers, K -16 students, and coastal managers.