Integrating Geomorphological and Paleoecological Studies to Reconstruct Neogene Environments of the Transantarctic Mountains

Abstract: This project studies the last vestiges of life in Antarctica from exceptionally well-preserved fossils of tundra life--mosses, diatoms, ostracods, Nothofagus leaves, wood, and insect remains recently discovered in ancient lake sediments from the McMurdo Dry Valleys. The area will be studied by an interdisciplinary team to elucidate information about climate and biogeography. These deposits offer unique and direct information about the characteristics of Antarctica during a key period in its history, the time when it was freezing. This information is critical for correlation with indirect proxies, such as though obtained from drill cores, for climate and state of the ice sheet. The results will also help understand the origin and migration of similar organisms found in South America, India and Australia. In terms of broader impacts, this project supports an early career researcher, undergraduate and graduate student research, various forms of outreach to K12 students, and extensive international collaboration. The work also has societal relevance in that the outcomes will offer direct constraints on Antarctica's ice sheet during a time with atmospheric CO2 contents similar to those of the earth in the coming centuries, and thus may help predictive models of sea level rise.摘要：本项目以麦克默多干谷（McMurdo Dry Valleys）新近于古代湖相沉积物中发现的苔原生物化石——苔藓（mosses）、硅藻（diatoms）、介形虫（ostracods）、南山毛榉（Nothofagus）叶片、木质残骸及昆虫遗体——为研究对象，探究南极洲的生命残存遗迹。该研究区域将由跨学科团队开展考察，以阐明区域气候与生物地理特征。这些沉积物可提供南极洲历史上关键冰封时期的独特直接的环境特征数据，该信息对于与通过钻探岩芯获取的、用于反演冰盖气候与状态的间接代用指标开展关联对比至关重要。研究结果还有助于阐释南美洲、印度与澳大利亚境内发现的同类生物的起源与迁徙演化过程。从拓展影响与社会效益层面来看，本项目将支持青年科研人员、本科生与研究生的科研工作，面向K12学生开展各类科普推广活动，并推进广泛的国际合作。本研究同时具备社会现实意义：在大气二氧化碳浓度与未来数百年地球大气水平相近的地质时期，研究结果可为南极冰盖的演化状态提供直接约束条件，进而助力海平面上升预测模型的优化。