Collaborative Research: Deducing Late Neogene Antarctic Climate from Fossil-Rich Lacustrine Sediments in the Dry Valleys

该项目研究南极洲西部干谷的古湖泊沉积物。这些沉积物特别令人兴奋，因为它们保存了700多万年的动植物，代表了在现代南极东部冰盖形成之前主导这一地区的生态系统的最后遗迹。它们独特的性质提供了一个连接现代和古代生态的机会。这些沉积物沿着古老的高山冰川边缘形成，含有粉砂、粘土和火山灰层；还有苔藓、昆虫和硅藻的冻干残留物。地质和生物分析提供了中新世中晚期（700万至1700万年前）的生态和环境条件的观点，这一时期跨越了南极东部冰盖过渡到目前稳定形式的关键时期。研究结果将干谷的现代湖泊置于一个长期的进化框架中，并允许与横贯南极山脉的其他富含化石的沉积物进行相关性和年代比较。火山玻璃碎片的化学指纹和年代测定也将有助于确定附近海洋岩心中含化石和含火山灰地层的年代，比如ANDRILL项目收集的那些岩心。更广泛的影响是博士后、研究生和本科层次的教育；以及研究机构和本科院校之间的合作。这项工作还提高了我们对地球历史上一个关键时期全球气候变化的理解。

This project studies ancient lake deposits from the western Dry Valleys of Antarctica. These deposits are particularly exciting because they preserve flora and fauna over seven million years in age that represent the last vestiges of ecosystems that dominated this area before formation of the modern East Antarctic ice sheet. Their unique nature offers a chance to bridge modern and ancient ecology. Formed along the margin of ancient alpine glaciers, these deposits contain layers of silt, clay, and volcanic ash; as well as freeze-dried remnants of mosses, insects, and diatoms. Geological and biological analyses provide a view of the ecological and environmental conditions during mid-to-late Miocene--seven to seventeen million years ago--which spans the critical period when the East Antarctic ice sheet transitioned to its present stable form. The results place the modern lakes of the Dry Valleys into a long-term evolutionary framework, and allow for correlation and dating comparisons with other fossil-rich deposits from the Transantarctic Mountains. Chemical fingerprinting and dating of volcanic glass shards will also help date fossil- and ash-bearing horizons in nearby marine cores, such as those to be collected under the ANDRILL program. The broader impacts are education at the postdoctoral, graduate, and undergraduate levels; and collaboration between a research institution and primarily undergraduate institution. The work also improves our understanding of global climate change during a critical period in the Earth's history.