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)提供资金的。该项目将通过对原始北大西洋和与西部内海接壤的沉积物岩心中全铁的铁同位素分析(D56Fe)来研究海洋缺氧事件II(OAEII，~94 Ma)的古地质史。OAEII沉积物的特征是高有机碳(OC)浓度，这可能是由于1)由于全球范围内更多的缺氧条件而增加了有机碳的保存，或者2)增加了表层海洋生产力。本研究的一个主要目的是研究铁对海洋生产力的影响以及海洋生态环境变化过程中整个碳循环的变化。为此，这项研究将调查热液输入到正己烷沉积物中的铁的相对输入，以及从陆架沉积物中迁移的铁的相对输入，因为陆架沉积物的d56Fe值应该明显低于热液来源。沉积铁的d56Fe值和FeT/Al比值将反映热液来源的相对贡献。这项研究将试图限制海洋铁在OAEII期间的总体质量平衡，从而扩大铁同位素分析在古环境评估中的应用。广泛的影响：该研究支持一名本科生、一名博士后和一名职业早期的女科学家。作为罗格斯大学海洋科学教育卓越中心的一部分，国际海洋研究所将与该中心主任S合作，将研究成果纳入针对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.