Late Eocene through Oligocene thermal and cryospheric evolution: Testing latitudinal SSTs and deepwater temperature vs. ice-volume changes

始新世晚期通过渐新世的热和冰圈演化：测试纬度海温和深水温度与冰量的变化始新世到渐新世的气候转变是过去5000万年来最深刻的海洋和气候变化。在这个项目中，将进行研究，以考察大约40-24年前全球从温暖的“温室”行星到凉爽的“冰库”行星的转变，并调查全球冰盖增长和随后的冰川变化对全球气候的影响。稳定的碳、氧同位素和微量元素(镁/钙)地球化学数据将从五个低纬大西洋工业/调查岩芯和四个ODP/DSDP站点仔细收集的原始、浮游和海底有孔虫中收集，以重建海表面温度、深水温度和冰量变化。有待解决的问题包括：1)在始新世-渐新世过渡期间，显著的深水冷却是否与大陆冰川作用的增加有关？2)始新世晚期至渐新世的海温是否高于今天，气候过渡是否与热带地区的最小冷却有关，从而导致早渐新世纬向海温梯度的增加比先前推断的更大？3)短暂的(1 MYR)冰川作用是否发生在始新世中晚期，然后发生在E-O转变之前？这些新数据将提供对瞬时气候变化和温室-冰库转变机制的洞察，并为试图重建地球历史气候变化的气候模型提供更可靠的信息。这项拟议的研究将涉及本科生和高中生，并为两名新近获得博士学位的女博士S提供支持。他们将通过地质博物馆和K-12教师培训参与公共宣传活动。

Late Eocene through Oligocene thermal and cryospheric evolution:Testing latitudinal SSTs and deepwater temperature vs. ice-volume changesThe Eocene to Oligocene climate transition was the most profound oceanographic and climatic change of the past 50 million years. In this project, research will be conducted to examine this global transition from a warm "greenhouse" planet to a cool "icehouse" planet, between ~40-24 myrs ago, as well as to investigate the effects of global ice-sheet growth and subsequent glacial variations on global climate. Stable carbon and oxygen isotopic and trace element (Mg/Ca) geochemical data will be collected from carefully collected, pristine, planktonic and benthic foraminifera from five low-latitude Atlantic industry/survey cores and four ODP/DSDP sites to reconstruct sea-surface temperatures, deepwater temperatures, and ice-volume changes. Questions to be addressed include: 1) Was significant deep-water cooling associated with an increase in continental glaciation during the Eocene-Oligocene transition? 2) Was late Eocene through Oligocene SSTs higher than today and was the climate transition associated with minimal cooling of the tropics, thereby producing a larger increase in the early Oligocene latitudinal SST gradient than previously inferred? 3) Did brief (1 myr) glaciations occur in the middle to late Eocene prior to E-O transition? These new data will provide insight into the mechanisms of transient climate change and the greenhouse-icehouse transition, as well as providing more robust information for climate models attempting to reconstruct Earth History climatic shifts. The proposed research will involve undergraduate and high school students and support two recent female Ph.D.'s. The PI's are involved with public outreach via the Geology Museum and K-12 teacher training.