CAREER: Organic Molecular Paleohypsometry: A new approach to quantifying the topographic history of the most rapidly eroding mountain belt on Earth

地球构造板块的运动控制着山脉的形成，影响地震的频率和震级，并影响碳氢化合物储集层形成所需的碳的运输和埋藏。尽管山脉在形成地质灾害、沉积物输出和全球环境条件方面至关重要，但很少有方法可以量化它们随时间的增长。这个项目的重点是开发一种新的工具来量化古山脉海拔的变化，这将对地球物理学、石油和天然气工业以及地表变化的研究产生影响。该项目通过为核心STEM学科的研究生培训提供支持，为培养具有全球竞争力的STEM（科学、技术、工程和数学）劳动力做出贡献，从而造福社会。进一步的社会效益包括，通过与哈特福德地区STEM巨头学校建立新的STEM教育推广合作，支持将地球科学教育纳入康涅狄格州科学标准，这些学校为多数少数民族提供服务。这个名为“山脉、河流和碳”的拓展项目为传统上代表性不足的学生提供了亲身接触地球科学研究的机会，与首席研究员进行日常接触，并为学生提供了参加康涅狄格大学校园内的研讨会的机会，该研讨会将现代河流的采样与工作实验室的活动以及与大学教职员工和学生的接触联系起来。这项研究还促进了美国和台湾科学家之间新的国际合作的发展。本研究正在开发一种新的地球化学工具，以沉积档案中保存的有机质同位素化学为基础，重建山带的古高程历史。这种方法被称为“有机分子古假说”，它利用了水和有机物稳定同位素组成随海拔高度的可测量和可预测的变化。不同海拔高度的有机质具有不同的稳定同位素特征，沉积有机质同位素化学的变化应反映出源区综合海拔的变化。台湾是全球隆升和侵蚀速度最快的地区之一，但到目前为止还没有适用于古海拔技术的地区，这种方法正在测试、改进并应用于台湾。该方法的校正包括对台湾各地的现代河流水、土壤和沉积物进行采样，以量化河流沉积物中有机质的同位素化学如何反映山区集水区有机物质的化学。该方法将应用于高平河和海底峡谷的海洋和陆地洪泛平原沉积物岩心，以研究最近晚更新世全球冰川消融期间有机分子特征的短时间尺度影响。此外，本研究将著重于分析台湾西部盆地500万年及更年轻的沉积物，以检验台湾造山带的有机分子记录，是否显示其在过去150万年中，是沿著岛屿的长度同时隆升，还是经历了高地形的南移。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。

Movement of Earth's tectonic plates controls the formation of mountains, affects the frequency and magnitudes of earthquakes and influences the transport and burial of carbon responsible for the formation of hydrocarbon reservoirs. Despite the critical importance of mountains in shaping geologic hazards, sediment export and global environmental conditions, there are few ways of quantifying their growth over time. This project is focused on development of a new tool to quantify changes in the paleoelevation of mountains that will have implications for geophysics, the oil and gas industry and studies of surface change. This project benefits society by contributing to the development of a globally competitive STEM (science, technology, engineering and mathematics) work force by providing support for graduate student training in a core STEM discipline. Further societal benefits include support for the integration of earth science education into Connecticut State Science Standards through the creation of a new STEM education outreach collaboration with Hartford area STEM Magnate schools that serve a majority minority population. This outreach program, entitled "Mountains, Rivers and Carbon", provides traditionally-underrepresented students with hands-on exposure to earth science research, routine engagement with the principal investigator, and opportunities for students to participate in a workshop at the University of Connecticut campus that bridges sampling in a modern river with activities in a working lab and engagement with university faculty and students. The research is also fostering the development of new international collaborations between U.S. and Taiwan scientists. This research is developing a new geochemical tool to reconstruct the paleoelevation history of mountain belts based on the isotope chemistry of organic matter preserved in sedimentary archives. This method, entitled Organic Molecular Paleohypsometry, exploits the measured and predictable variation in the stable isotope composition of water and organic matter as a function of elevation. Organic matter sourced from different elevations is characterized by distinct stable isotopic signatures, and changes in the isotope chemistry of sedimentary organic matter should reflect changes in the integrated elevation of the source area. The method is being tested, refined and applied to Taiwan, one of the fastest uplifting and eroding regions of the globe, but a region for which no paleoelevation technique has been applicable, until now. Calibration of this method includes sampling of modern river waters, soils and sediments from across Taiwan to quantify how the isotope chemistry of organic matter in river sediments reflects the chemistry of organic material from across mountainous catchments. This approach will be applied to geologically-recent marine and terrestrial floodplain sediment cores from the Gaoping river and submarine canyon to examine short-timescale effects on organic molecular signatures during the recent late Pleistocene global deglaciation. In addition, the proposed research focuses on the analysis of 5 million year and younger sediments from basins along western Taiwan to test whether organic molecular records of the Taiwan orogen show that it was uplifted simultaneously along the length of the island, or experienced a southward propagation of high topography over the last 1.5 million years.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.