When did the South Atlantic Ocean ventilate? Testing for paleogeographic controls on Cretaceous carbon burial

海洋在调节地球的碳循环、气候和宜居性方面发挥着关键作用。地球科学家依靠海洋盆地的沉积记录来了解地球及其海洋如何在长时间尺度上对地质和环境变化作出反应。最终，更好地理解这些反馈可以预测地球上的生命如何对气候或构造等外部驱动因素做出反应或将如何反应。该项目将研究1.5亿至1亿年前南大西洋形成期间的物理表面过程、海洋氧化作用和有机碳埋藏之间的联系，这一时期以温室到温室气候条件为特征。更广泛地说，这个项目将(1)产生新的高中教育和专业发展内容；(2)加强巴塔哥尼亚南部国际研究、合作和社区参与的基础设施；(3)促进STEM本科生的教学、指导和研究。大陆分裂为有机碳埋藏提供了适宜的条件（例如，受限的早期海洋盆地）。然而，不太清楚的是，这些条件何时/如何被持续的大陆分裂和海洋盆地的通风和循环所逆转。该项目旨在确定与早白垩世冈瓦纳大陆分裂期间南大西洋主要海洋门户打开相关的当地盆地环境、区域构造和全球气候变化的沉积响应。南巴塔哥尼亚的初步结果表明，在记录环境变化的南部大洋盆地地层学中存在明显的岩性和化学地层学界线。利用高精度的地质年代学和沉积的化学环境来限制沉积的时间，可以将巴塔哥尼亚的研究与其他与年龄相关的盆地进行比较。此外，通过与智利古生物学家合作，该项目将为正在进行的关于环境对白垩纪海洋脊椎动物分布和行为模式的影响的古生物学研究提供信息。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。

The oceans play a critical role in modulating Earth’s carbon cycle, climate, and habitability. Geoscientists rely on the sedimentary record of ocean basins to understand how the Earth and its oceans respond to geological and environmental change over long timescales. Ultimately, a better understanding of these feedbacks allows for predictions about how life on our planet has responded, or will respond, to external drivers such as climate or tectonics. This project will investigate links between physical surface processes, ocean oxygenation, and organic carbon burial during the establishment of the South Atlantic Ocean from 150-100 million years ago, a time period characterized by greenhouse to hothouse climate conditions. More broadly, this project will (1) generate new high school educational and professional development content; (2) enhance infrastructure for international research, collaboration, and community engagement in southern Patagonia; and (3) promote teaching, mentoring, and research with undergraduates in STEM.Continental break-up facilitates suitable conditions (e.g., restricted incipient ocean basins) for organic carbon burial. It is less clear, however, when/how these conditions are reversed by continued continental breakup and ocean basin ventilation and circulation. This project aims to determine the depositional response to local basin setting, regional tectonics, and global climate changes associated with the opening of a major oceanic gateway in the South Atlantic during the Early Cretaceous breakup of Gondwana. Preliminary results from southern Patagonia show there are discernable lithologic and chemostratigraphic boundaries in the stratigraphy of southern ocean basins recording changing environmental conditions. Constraining the timing of deposition with high precision geochronology and the chemical environments of deposition allows for comparisons between this study in Patagonia with age-correlative basins elsewhere. Moreover, through collaborations with Chilean paleontologists, the project will inform ongoing paleobiology studies of the environmental influences on the distribution and behavioral patterns of Cretaceous marine vertebrates.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.