Antarctic climate history at the onset of glaciation: Was there ice in the greenhouse?

在大约5000万年前极端温暖的全球温室时期，南极洲基本上是无冰的，拥有温带森林。随后数百万年的冷却导致南极气候在始新世末期稳步恶化，最终在渐新世开始时(约3400万年前)达到大范围冰川的顶峰。无论是冰盖发育之前的气候变化，还是温室期间可能存在的冰川，甚至小冰盖，都是有争议的。最近的研究支持在大冰川之前的冰川活动，但有争议的是，也解释了在始新世早期(和更温暖的)时间段，南极东部更多的大量冰盖。该项目将通过应用现有的沉积学、矿物学和地球化学方法，以及新的代理和岩心成像方法的发展和应用，以重建南极的古气候和随时间的变化，从而获得对南极早期气候历史的新见解。该项目将重点调查即将在西南极阿蒙森海(2019年1月至3月)进行的国际海洋发现计划(IODP)第379次考察队将发现的新钻芯序列，并结合对过去科学钻探项目中分布在南极边缘周围的现有钻芯的研究。

During the extremely warm global 'greenhouse' period ~50 million years ago, Antarctica was mostly ice free and hosted temperate forests. Subsequent cooling over many millions of years resulted in a steady deterioration of Antarctic climate at the end of the Eocene Epoch, eventually culminating in widespread glaciation at the beginning of the Oligocene Epoch (~34 million years ago). Both climate variability prior to ice-sheet development and possible existence of glaciers, or even small ice sheets, during greenhouse intervals are debated. Recent studies support glacial activity in the lead up to major glaciation, but, controversially, more substantial ice cover in East Antarctica during earlier (and warmer) time intervals of the Eocene has also been interpreted.This project will gain new insight into the early climate history of Antarctica through application of established sedimentological, mineralogical, and geochemical methods, along with development and application of novel proxy and core imaging methods for reconstructing Antarctic palaeoclimates and variations through time. The project will focus on the investigation of new drillcore sequences to be recovered on upcoming International Ocean Discovery Program (IODP) Expedition 379 to the Amundsen Sea, West Antarctica (Jan-Mar 2019), combined with study of existing drillcores distributed around the Antarctic margin from past scientific drilling projects.