地质科技通报 (May 2022)
Sediment source-to-sink processes of the southeastern Indian Ocean during the Late Eocene-Oligocene and their potential significance for paleoclimate
Abstract
Understanding the paleoclimate responses in Southern Ocean and its surrounding land can help us to better explore the major climate transition mechanisms in geological history and predict the response ofthe earth system to abrupt climate changes in the future, while, there is still a lack of research on the paleoclimatere sponse of the surrounding land in Southern Ocean.Based on the age framework, major, traceand rare earth element compositions of the deep-sea sediments at Site U1516 of the International Ocean Discovery Program (IODP) 369, we determined that the sediments were mainly from the southwest continent of Australia, and then reconstructed the chemical weathering history of the source area on the tectonic time scale.In addition, we combined with the previous research results to discuss the paleoclimate evolution of continents surrounding Southern Ocean during the Late Eocene-Oligocene climate transition period and its response toglobal climate changes and regional paleogeographic changes.During the Eocene-Oligocene transition (e.g., 34.1 to 33.6 Ma and 31.3 to 29.8 Ma), the paleoclimate in the source area was mainly controlled by the significant changes in the paleogeographic pattern of the adjacent area, which was characterized by the climate conditions tending to bedry and cold and the decrease of chemical weathering intensity on the land surface.During the period of 33.6 to 31.3 Ma and 29.8 to 25.2 Ma, the palaeoclimate of the source area mainly responded to global climate changes.In theformer stage, the paleoclimate changed from dry and cold to wet and hot, the intensity of chemical weathering on the land surface increased correspondingly; In the latter stage, the climate maintained in a relatively stable dry and cold state, the intensity of chemical weathering on the land surface is also weak.
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