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Climate variability at the Middle Pleistocene Transition 900 kyr ago (CLIM900K)

900 年前中更新世过渡时期的气候变率 (CLIM900K)

基本信息

批准号：
NE/R000204/1
负责人：
Polychronis Tzedakis
金额：
$ 67.1万
依托单位：
University College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FR000204%2F1
关键词：
Climate variability Middle Pleistocene Transition

项目摘要

The prolongation and intensification of glacial cycles over the course of the Middle Pleistocene Transition (MPT; ~1.25-0.65 Ma) remains one of the major unsolved mysteries of Quaternary ice ages. Within the MPT, the interval from Marine Isotope Stage (MIS) 25 to 21 (~0.965-0.850 Ma) is thought to represent a fundamental shift in the mode of glacial cycles, with the appearance of a 100-kyr glacial cycle culminating in the first major Northern Hemisphere glaciation, but there is considerable uncertainty over the extent of ice volume increase. Moreover, while prominent debates centre on the causes of the transition, we are still lacking an adequate description and understanding of the evolution of climate variability over this interval. We propose to provide a comprehensive assessment of orbital- and millennial-scale climate changes during MIS 25-21, through joint pollen and foraminiferal isotopic and Mg/Ca analyses at unprecedented resolution from Site U1385 on the Portuguese Margin, a key location for linking changes in the ocean, atmosphere and biosphere. Results will transform our understanding of the magnitude of ice volume increase, the interaction of orbital- and millennial-scale variability and its role in glaciation and deglaciation, and impacts on plant biodiversity during this interval and will provide a benchmark for future studies on the transition into the 100-kyr world.

中更新世(MPT；约1.25-0.65 Ma)冰川旋回的延长和强化一直是第四纪冰期尚未解开的主要谜团之一。在海洋同位素阶段25到21(~0.965-0.850 Ma)之间的时间间隔被认为代表了冰川循环模式的根本转变，出现了100Kyr的冰川循环，最终导致了北半球第一次主要冰川作用，但对于冰量增加的程度存在相当大的不确定性。此外，虽然突出的辩论集中在过渡的原因上，但我们仍然缺乏对这段时间内气候变异性演变的充分描述和理解。我们建议对MIS25-21期间轨道和千年尺度的气候变化进行全面评估，从葡萄牙边缘的U1385站点以前所未有的分辨率联合进行花粉和有孔虫同位素和镁/钙分析，U1385站点是连接海洋、大气和生物圈变化的关键位置。这些结果将改变我们对冰量增加幅度、轨道和千年尺度变率的相互作用及其在冰川和冰川消融中的作用以及对这段时间内植物生物多样性的影响的理解，并将为未来过渡到100 KYR世界的研究提供基准。