Collaborative Research: Calibrating the end-Ediacaran Extinction with U-Pb Geochronology & Chemostratigraphy at a New Precambrian-Cambrian Boundary Site in Namibia & South

合作研究：用 U-Pb 地质年代学校准埃迪卡拉末期灭绝

• 批准号: 1827715
• 负责人: Jahandar Ramezani
• 金额: $ 30.06万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1827715&HistoricalAwards=false
• 关键词: Collaborative; Research; Calibrating; end; Ediacaran; Collaborative; Research; Calibrating; end; Ediacaran

The first appearance and rapid diversification of complex, multicellular animals at the dawn of the Cambrian (~540 million years ago) is conceivably the single most significant episode in the evolution of life on Earth, as it laid out the initial blueprints for the vast majority of life forms that exist today. Understanding the driving mechanisms of the Cambrian 'explosion' have been challenging because life forms that dominated the preceding period, the Ediacaran, have a sparse fossil record. In addition, the marine sedimentary rocks that preserve the Ediacaran-Cambrian transition are now scattered across the continents, hampering an unequivocal reconstruction of life and the environment at this crucial junction of the geologic history. This study focuses on key outcrops of the Ediacaran-Cambrian marine deposits with spectacular fossils and high potential for precise isotopic dating in a previously unexplored region near the Namibia-South Africa border. The results will provide new insights into the rates of paleoenvironmental and ocean chemical change during this critical time interval. In addition to public presentations and scholarly publications, a comprehensive program of educational, training, and outreach activities are planned.This project employs an integrated program of field mapping, sedimentology, chemo- and bio-stratigraphy on newly discovered marine carbonate-rich and fossiliferous Ediacaran-Cambrian sections on either side of the Orange River in Namibia and South Africa with abundant intercalated ash beds suitable to U-Pb geochronology. It will provide a high-resolution record that will help to unravel the mode and rates of biotic and coeval environmental changes at the close of the Proterozoic. The results will be a major step forward in testing the hypothesis that there were globally synchronous environmental perturbations that were genetically associated with biotic turnover across the Ediacaran-Cambrian boundary, and will lead to a better understanding of the driving mechanisms of the Cambrian radiation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

可以想象，复杂的多细胞动物的首次出现和快速多样化是在地球上生命进化中最重要的一集，因为它列出了当今存在的绝大多数生命形式的最初蓝图，这是可以想象的。了解寒武纪“爆炸”的驾驶机制一直充满挑战，因为在前一个时期占主导地位的生命形式（Ediacaran）具有稀疏的化石记录。此外，保留Ediacaran-Cambrian过渡的海洋沉积岩现已散布在整个大陆上，阻碍了地质历史的关键交界处的生命和环境的明确重建。这项研究着重于具有壮观化石的Ediacaran-Cambrian海洋沉积物的关键露头，并在纳米比亚 - 南非洲边界附近的一个以前未开发的地区进行精确的同位素约会的潜力很高。结果将为您在此关键时间间隔内对古环境和海洋化学变化的速率提供新的见解。除了公开演讲和学术出版物外，还计划了一项全面的教育，培训和外展活动的计划。该项目采用了现场映射，沉积学，化学疗法，化学和生物学的综合计划，对新发现的碳酸盐富含海洋碳酸盐和化石式的Esheraby bedia interc senterc offiacia and southerc的纽约河中的纽约河中的纽约河中的Nammibia和Southc的纽约河中的Nammibia contractia inammibia contractia inmagia coptria nammibia contractia inmagia contractia inmagia coptria。 U-PB年代学。它将提供高分辨率的记录，有助于揭示proterokoic结束时生物和同时环境变化的模式和速率。结果将是测试以下假说的主要一步，即在遗传上与跨伊迪亚卡兰 - 卡姆布里亚边界的生物转移相关，并将更好地理解Cambrian辐射的驾驶机制，这反映了NSF的法定任务和综述，这是通过评估的范围，并且通过评估了范围，这表明了这一奖项的范围。