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

非技术性说明：这一为期4年的项目正在评估在南极洲西部半岛的西摩岛发现的高南纬度南极-古近纪露头剖面的灭绝模式和沉积条件的证据。该团队正在使用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，地球化学和微体化石。这项研究将有助于确定K-Pg大灭绝是一个单阶段还是双阶段事件，以及西摩岛地区在地质历史上是一个受限制的亚氧海洋环境还是一个开放的混合大陆架。该奖项包括一项各级学生培训综合计划，并通过与一名在一所为代表性不足的学生服务的学校工作的高中地球科学教师建立突出的伙伴关系而得到加强。技术说明：拟议的研究正在应用多种技术来解决最近研究存在分歧的一个总体研究问题：来自南极洲西摩岛独特露头的化石证据是否与单阶段或双阶段灭绝一致？在一个两阶段模型中，第一次灭绝将主要影响底栖生物，并将在K-Pg边界的单独灭绝之前约150千年发生。然而，这种早期灭绝可以合理地解释为一个未被识别的相控制，是由表面风化掩盖。该团队正在使用微体化石证据以及详细的沉积岩石学和地球化学数据来评估西摩岛的化石证据是否与单阶段或双阶段灭绝过程一致。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K-PG间隔的相变，这将解释明显的早期灭绝。正在对岩心沉积有孔虫、硅质微体化石和钙质超微化石的样品进行评估，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，该小组正在使用多种地球化学方法来评估是否有证据表明塞莫尔地区盆地存在间歇性缺氧或euxinia和/或物理限制。从这个分析的数据将表明，如果这个地区是一个有限的，亚氧海洋环境或开放的混合shelf.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.