Collaborative Research: Coring Seymour Island (CSI) Antarctica: Evaluating Causes and Effects of the End Cretaceous Mass Extinction

非技术描述：这个为期4年的项目正在评估南纬高纬度白垩纪-古近纪（K-Pg）露头剖面中灭绝模式和沉积条件的证据，该露头剖面位于南极半岛西部的Seymore岛。该团队正在使用在风化层以下收集的沉积物样本来评估目标地层间隔中的详细沉积结构、地球化学和微化石。这项研究将有助于确定K-Pg大灭绝是一个单阶段还是两个阶段的事件，以及西摩岛地区在过去的地质环境中是一个受限的、缺氧的海洋环境还是一个开放的、混合良好的大陆架。该奖项包括一项针对各级学生培训的综合计划，并通过与在一所学校为代表性不足的学生服务的高中地球科学教师的突出伙伴关系得到加强。技术描述：拟议的研究正在应用多种技术来解决一个最近研究存在分歧的首要研究问题：来自南极洲西摩岛一个独特的裸露岩层的化石证据是否与单阶段或双阶段灭绝相一致？在两个阶段的模型中，第一次灭绝将主要影响底栖生物，并且发生在K-Pg边界的单独灭绝之前约150万年。然而，这种早期灭绝似乎可以用一种未被识别的相控制来解释，这种相控制被表面风化所掩盖。该团队正在使用微化石证据和详细的沉积岩石学和地球化学数据来评估来自西摩岛的化石证据是否与单阶段或双阶段灭绝过程相一致。该团队正在使用详细的沉积岩石学和地球化学方法来测试整个K-PG区间的相变化，这将解释明显的早期灭绝。岩心沉积有孔虫、硅质微化石和钙质纳米化石的样本正在进行评估，以提供高分辨率的地层分辨率，并评估是否存在早期灭绝的证据。此外，该团队正在使用多种地球化学方法来评估是否存在间歇性缺氧或缺氧和/或Seymore地区盆地的物理限制的证据。这一分析的数据将表明这一地区是受限制的、缺氧的海洋环境还是开放的混合良好的陆架。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical description:This 4-year project is evaluating evidence of extinction patterns and depositional conditions from a high southern latitude Cretaceous-Paleogene (K-Pg) outcrop section found on Seymore Island, in the Western Antarctic Peninsula. The team is using sediment samples collected below the weathering horizon to evaluate detailed sedimentary structures, geochemistry, and microfossils in targeted stratigraphic intervals. The study will help determine if the K-Pg mass extinction was a single or double phased event and whether Seymour Island region in the geological past was a restricted, suboxic marine environment or an open well-mixed shelf. The award includes an integrated plan for student training at all levels, enhanced by a highlighted partnership with a high school earth sciences teacher working in a school serving underrepresented students. Technical description: The proposed research is applying multiple techniques to address an overarching research question for which recent studies are in disagreement: Is the fossil evidence from a unique outcropping on Seymour Island, Antarctica consistent with a single or double phased extinction? In a two-phased model, the first extinction would affect primarily benthic organisms and would have occurred ~150 kiloyears prior to a separate extinction at the K-Pg boundary. However, this early extinction could plausibly be explained by an unrecognized facies control that is obscured by surficial weathering. This team is using microfossil evidence with detailed sedimentary petrology and geochemistry data to evaluate if the fossil evidence from Seymour Island is consistent with a single or double phased extinction process. The team is using detailed sedimentary petrology and geochemistry methods to test for facies changes across the K-PG interval that would explain the apparent early extinction. Samples of core sedimentary foraminifera, siliceous microfossils, and calcareous nannofossils are being evaluated to provide a high-resolution stratigraphic resolution and to evaluate whether evidence for an early extinction is present. Additionally, the team is using multiple geochemical methods to evaluate whether there is evidence for intermittent anoxia or euxinia and/or physical restriction of the Seymore region basin. Data from this analysis will indicate if this region was a restricted, suboxic marine environment or an open well-mixed shelf.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.