Eocene to Oligocene cooling and ice growth based on the geochemistry of interglacial mudstones from the East Antarctic continental shelf
Eocene to Oligocene cooling and ice growth based on the geochemistry of interglacial mudstones from the East Antarctic continental shelf
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DOI：
10.1017/s0954102023000159
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发表时间：
2023-08
影响因子：
1.6
通讯作者：
J. Light;S. Passchier
中科院分区：
文献类型：
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作者：
J. Light;S. Passchier
始新世-渐新世过渡在C。3400万年前（Ma）标志着全球从温室到冰库的变化和东南极冰盖（EAIS）的建立。人们对间冰期期间冰盖的行为如何在这种气候转变中发生变化知之甚少。我们分析了主要的，微量和稀土元素数据晚始新世间冰期泥岩从Pravenz湾在大洋钻探计划网站1166和早渐新世间冰期泥岩从综合大洋钻探计划网站U1360威尔克斯大陆架。这两个地点具有可比的冰海沉积环境。岩相和物源在现场1166 Preniz湾是一个晚始新世冰川退缩的兰伯特地堑的指示。古气候代用指标，包括化学蚀变指数，平均年温度和平均年降水量，显示了一个主导的温暖和潮湿的古气候晚始新世间冰期。与此相反，在站点U1360，在渐新世早期，物源和间冰期风化制度保持相对稳定的物理风化条件。这些结果证实，EAIS大幅撤退，在晚始新世间冰期和冰下盆地可能仍然在最早的渐新世间冰期部分冰川。
The Eocene-Oligocene Transition at c. 34 million years ago (Ma) marked the global change from greenhouse to icehouse and the establishment of the East Antarctic Ice Sheet (EAIS). How the ice-sheet behaviour changed during interglacials across this climate transition is poorly understood. We analysed major, trace and rare earth elemental data of late Eocene interglacial mudstone from Prydz Bay at Ocean Drilling Program Site 1166 and early Oligocene interglacial mudstone from Integrated Ocean Drilling Program Site U1360 on the Wilkes Land continental shelf. Both sites have comparable glaciomarine depositional settings. Lithofacies and provenance at Site 1166 in Prydz Bay are indicative of a late Eocene glacial retreat in the Lambert Graben. Palaeoclimate proxies, including the Chemical Index of Alteration, mean annual temperature and mean annual precipitation, show a dominant warm and humid palaeoclimate for the late Eocene interglacial. In contrast, at Site U1360, in the early Oligocene, the provenance and interglacial weathering regime remained relatively stable with conditions of physical weathering. These results confirm that the EAIS substantially retreated periodically during late Eocene interglacials and that subglacial basins probably remained partially glaciated during interglacials in the earliest Oligocene.