Collaborative Research: Ocean Redox Evolution at the Dawn of Animal Life: An Integrated Geological and Geochemical Study of the Ediacaran Yangtze Platform in South China

合作研究：动物生命初期的海洋氧化还原演化：华南埃迪卡拉纪扬子地台综合地质与地球化学研究

• 批准号: 0745605
• 负责人: Timothy Lyons
• 金额: $ 9.8万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0745605&HistoricalAwards=false
• 关键词: Collaborative; Research; Ocean; Redox; Evolution

EAR 0745825COLLABORATIVE RESEARCH: Ocean Redox Evolution at the Dawn of Animal Life: An Integrated Geological and Geochemical Study of the Ediacaran Yangtze Platform in South ChinaABSTRACTRecent studies suggested that major oxidation events during the Ediacaran Period (ca. 635 Ma to 542 Ma) triggered the first appearance and evolution of the Earth?s earliest animal life, but critical evaluation of the proposed linkages is limited by the lack of a detailed documentation on spatial and temporal redox changes of Ediacaran oceans and the responses of Ediacaran organisms to such redox changes. An integrated geological, geochemical, and paleobiological study of the Ediacaran Yangtze platform is aimed at improving our understanding of the interplay between ocean redox changes, geochemical anomalies, and early animal evolution in a rarely preserved, fossiliferous sedimentary archive. The proposed research is designed to test the following hypotheses: (1) the deep ocean was anoxic/euxinic until ca. 551 Ma; (2) episodic oxidation of a large oceanic dissolved organic carbon (DOC) reservoir led to the formation of geochemical anomalies including unusually negative carbon isotope excursions; and (3) the spatial and temporal distribution of Ediacaran organisms was coupled with ocean redox conditions. Objectives of the research are to determine: (1) carbonate and organic carbon isotope variability across the basin to test a potential surface-to-deep ocean carbon isotope gradient that may have been much greater than in the modern ocean; (2) spatial and temporal sulfur isotope variability to test the persistence and/or fluctuation of sulfate reduction and sulfur disproportionation across the basin; (3) spatial and temporal changes of molybdenum (Mo) concentrations and Mo isotopes, iron (Fe) speciation and Fe isotopes to determine the secular redox evolution and potential redox fluctuation associated with stable isotope excursions; and (4) spatial and temporal occurrences of Ediacaran fossils and their relationships with geochemical boundaries/anomalies. The ultimate goal of the research is to integrate paleontological and geochemical data to test the coupling between redox conditions and spatial/temporal patterns of Ediacaran organisms. Anticipated data would provide important information for our understanding of the environmental forces related to a significant biological innovation in Earth history.The project will partially support four PhD students from University of Nevada Las Vegas, Virginia Polytechnic Institute, University of California at Riverside, and Arizona State University. The project develops new collaborations between researchers at four different institutions and provides a broad training opportunity for interactions among students with different research foci. Research results will be integrated with courses taught at four institutions and will enhance undergraduate involvement in the research project at four institutions. The project will also promote international collaborations with scientists from institutions in China and Canada.

EAR 0745825综合研究：动物生命曙光时的海洋氧化还原进化：一项对南方中国阿纳布斯特拉克斯特拉氏菌的Ediacaran扬格兰平台的地质和地球化学研究表明，Ediacaran期间的重大氧化事件表明，Ediacaran时期期间的氧化事件（Ca. 635 MA至542 MA）的兴起，并触发了Alliest of Eartiest and Eartiest of Eartiest？由于缺乏有关Ediacaran海洋的空间和颞氧化还原变化的详细文档的限制，以及Ediacaran生物对此类氧化还原变化的反应。 Ediacaran长江平台的一项综合地质，地球化学和古生物学研究旨在提高我们对海洋氧化还原变化，地球化学异常和早期动物进化之间相互作用的理解，这是一个很少保存的，化石沉积的沉积档案。拟议的研究旨在检验以下假设：（1）深海一直缺氧/耐热直到大约。 551 MA; （2）大海洋溶解有机碳（DOC）储层的情景氧化导致地球化学异常形成，包括异常负的碳同位素偏移； （3）Ediacaran生物的空间和时间分布与海洋氧化还原条件相结合。该研究的目的是确定：（1）整个盆地的碳酸盐和有机碳同位素变异性，以测试可能比现代海洋大得多的潜在地表到深海同位素梯度； （2）空间和颞硫同位素的变异性，以测试整个盆地硫酸盐还原和硫酸盐的持久性和/或波动； （3）钼（MO）浓度和MO同位素，铁（Fe）物种形成和Fe同位素的空间和时间变化，以确定世俗的氧化还原进化以及与稳定的同位素偏移相关的潜在氧化还原波动； （4）Ediacaran化石的空间和时间出现及其与地球化学边界/异常的关系。该研究的最终目的是整合古生物学和地球化学数据，以测试氧化还原条件与Ediacaran生物的空间/时间模式之间的耦合。预期的数据将为我们理解与地球历史上重要的生物创新有关的环境力量提供重要信息。该项目将部分支持内华达大学拉斯维加斯大学，弗吉尼亚州理工学院，加利福尼亚大学河滨大学和亚利桑那州立大学的四名博士学位学生。该项目开发了四个不同机构研究人员之间的新合作，并为不同研究重点的学生之间的互动提供了广泛的培训机会。研究结果将与四个机构教授的课程融合，并将增强本科在四个机构的研究项目中的参与。该项目还将促进与中国和加拿大机构的科学家的国际合作。