Global Eustasy or Tectonic Subsidence? Investigating Controls on Basin Evolution During Cenozoic Plate Reorganization, Magallanes Basin, Patagonia

构造活动和气候相互作用控制着山脉的生长、陡峭地形的侵蚀以及低洼大陆边缘海洋和陆地条件之间的波动。处于大陆分离的复杂构造板块环境中的大陆对构造变形和海平面变化尤为敏感，它们共同调节着主要大陆块之间的生物地理路径和海洋盆地之间的全球海洋/大气环流。本项目利用地层学、地质年代学、盆地模拟、构造地质学和古生物学等方法，研究了南美洲（智利和阿根廷）新生代麦哲伦—南方区在全球气候的一个重要时间间隔内，构造变形、海平面和气候对海岸沉积模式和古地理的影响。该项目通过以下方式推进科学在我们社会中的作用：1)通过开发板块构造、全球气候和古地理的实地学习模块，吸引普通公众和参加通识教育课程的大学生；2)促进女性更多地参与科学技术；3)为研究生和本科生提供国际研究和培训机会；4)促进美国和智利学术机构和区域公园组织之间新的国际合作。美国国家科学基金会国际科学与工程办公室为与该项目相关的国际活动提供支持。本项目的主要研究目的是评价在全球气候的一个重要时间间隔内，南美洲麦哲伦—南方区海侵和大陆沉积物扩散模式的控制因素。本研究旨在验证巴塔哥尼亚中新生代大西洋海侵是由安第斯山脉变形和德雷克海峡开通期间的构造荷载和沉积环境加深引起的假设。本项目还研究了插入式粗粒前积矿床与高地沉积物源区的逆冲历史和地理变化之间的联系。将结合地层学、盆地模拟、构造填图和沉积物源工具（碎屑锆石年代学、砂岩岩石学和泥岩地球化学）来评估始新世至中新世中期高地源区的构造和气候变化如何影响沉积样式、粒度、堆积速率和盆地古地理。由碎屑磷灰石热年代学得出的侵蚀速率将进一步解决冲断带变形和气候事件的潜在影响。本项目通过以下方式促进了对大陆岩石圈变形认识的科学进展：1)评价安第斯造山主要阶段弧后前陆盆地演化的走向差异；2)为不同的中新生代巴塔哥尼亚化石组合提供改进的年代地层格架；3)研究造山古地理、海侵、沉积脉冲和生物事件之间的关系；4)整合新的数据集，改进造山系统岩石圈变形和气候过程的数值模型。

Tectonic activity and climate interact to control the growth of mountains, erosion of steepened topography, and fluctuations between marine and terrestrial conditions along low-lying continental margins. Continents located in complex tectonic plate settings undergoing continental separation are especially sensitive to changes in tectonic deformation and sea level, which together modulate biogeographic pathways between major landmasses and global ocean/atmosphere circulation between ocean basins. This project uses stratigraphy, geochronology, basin modeling, structural geology, and paleobiology in the Cenozoic Magallanes-Austral region of South America (Chile and Argentina) to investigate how tectonic deformation, sea level, and climate affect coastal depositional patterns and paleogeography during an important time interval for global climate. The project advances the role of science in our society by 1) engaging the general public and college students enrolled in general education courses by developing a field-based learning module on plate tectonics, global climate, and paleogeography, 2) promoting increased participation of women in science and technology, 3) supporting international research and training opportunities for graduate and undergraduate students, and 4) stimulating new international collaborations between U.S. and Chilean academic institutions and regional parkland organizations. The NSF Office of International Science and Engineering is providing support for international activities associated with this project. The primary research objective of this project is to evaluate the controlling factors on marine transgressions and continental sediment dispersal patterns in the Magallanes-Austral region of South America during an important time interval for global climate. This work aims to test the hypothesis that the middle Cenozoic Atlantic transgressions in Patagonia were caused by tectonic loading and deepening of sedimentary environments during Andean deformation and opening of the Drake Passage. This project also investigates how the intercalated coarse-grained progradational deposits are linked to thrusting history and physiographic changes in upland sediment source areas. Stratigraphy, basin modeling, structural mapping, and sedimentary provenance tools (detrital zircon geochronology, sandstone petrography, and mudstone geochemistry) will be combined to evaluate how tectonic and climatic changes in upland source areas affect sedimentation style, grain size, accumulation rate, and basin paleogeography during Eocene through middle Miocene time. Erosion rates derived from detrital apatite thermochronology will further resolve potential influences from thrust-belt deformation and climatic events. This project promotes scientific progress on understanding the deformation of the continental lithosphere by: 1) evaluating along-strike differences in retroarc foreland basin evolution during a major phase of Andean orogenesis, 2) contributing an improved chronostratigraphic framework for the diverse middle Cenozoic Patagonian fossil assemblages, 3) investigating relationships between orogenic paleogeography, transgressions, sediment pulses, and biotic events, and 4) integrating new datasets for improved numerical models of lithospheric deformation and climatic processes in orogenic systems.