Assessing the paleoenvironmental and geobiological significance of carbonates from the Eocene-Oligocene boundary of the White River Group

地质记录提供了过去气候和古代生态系统的档案。重建过去的气候是我们了解地球历史的关键，并提供了对现代生态系统如何对当前和未来的气候变化作出反应的见解。这项研究将调查南达科他州西南部的古湖泊沉积物在向现代“冰窖”气候过渡期间保存的气候变化程度和生态系统对这些变化的响应。这些结果将增强我们对地球历史这一关键时期的理解，并为改进预测现代气候变化影响的模型提供必要的知识。这项研究还将为本科生和研究生提供专业培训，并使南达科他州矿山地质博物馆和荒地国家公园的教育资源得以开发，使游客了解该地区岩石的科学重要性。该项目由沉积地质学和古生物学计划（SGP）和促进竞争性研究的既定计划（EPSCoR）共同资助。始新世—渐新世转变发生在~ 3400万年前，其特征是全球平均降温~2.5℃，南极形成永久冰盖，海洋生态系统发生灭绝事件。然而，在这段时间内，北美内陆的气候变化程度和生态系统对这些变化的反应尚不清楚。在此期间形成的湖泊沉积物保存在南达科他州的荒地，提供了这些变化的记录，但以前只得到有限的研究。本研究主要有两个目标：1)确定湖泊沉积的范围，了解其沉积学和地层学；2)通过时空分析这些岩石的地球化学组成，重建古环境条件的变化。这些努力将有助于更好地了解陆地对气候变化的反应。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 geologic record provides an archive of past climates and ancient ecosystems. Reconstructing past climates is key to our understanding of Earth history and provides insight into how modern ecosystems may react to current and future climatic changes. This study will investigate the degree of climatic change and the ecosystem response to these changes preserved in ancient lake deposits from southwestern South Dakota during the transition into the modern “icehouse” climate. These results will enhance our understanding of this key interval of Earth history and provide knowledge necessary to improve models for predicting the effects of modern climate change. This study will also provide professional training for undergraduate and graduate students and enable the development of educational resources at the South Dakota Mines Museum of Geology and Badlands National Park for visitors on the scientific importance of the rocks in this region. This project is jointly funded by the Sedimentary Geology and Paleobiology Program (SGP) and the Established Program to Stimulate Competitive Research (EPSCoR).The Eocene-Oligocene Transition occurred ~34 million years ago and was characterized by an average global cooling of ~2.5oC, the formation of permanent Antarctic ice caps, and an extinction event in ocean ecosystems. However, the degree of climatic change and the ecosystem response to these changes in the interior of North America during this time is unclear. Lake deposits formed during this time that are preserved in the Badlands of South Dakota provide a record of these changes but have previously received only limited study. This research has two primary objectives: 1) to identify the extent of these lake deposits and understand their sedimentology and stratigraphy, and 2) to analyze the geochemical composition of these rocks through time and space to reconstruct changes in paleoenvironmental conditions. These efforts will provide a better understanding of terrestrial responses to climate change.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.