气候变化领域集成服务门户(CCPortal): Evidence for a Northern Hemispheric trigger of the 100,000-y glacial cyclicity

CCPortal

DOI	10.1073/pnas.2020260118
	Evidence for a Northern Hemispheric trigger of the 100,000-y glacial cyclicity
	Yehudai M.; Kim J.; Pena L.D.; Jaume-Segui M.; Knudson K.P.; Bolge L.; Malinverno A.; Bickert T.; Goldstein S.L.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:46
英文摘要	The causes of the Mid-Pleistocene Transition, the shift from ∼41-ky to 100-ky interglacial-glacial cycles and more intense ice ages, remain intensely debated, as this fundamental change occurred between ∼1,250 and 650 ka without substantial changes in astronomical climate forcings. Recent studies disagree about the relative importance of events and processes in the Northern and Southern Hemispheres, as well as whether the shift occurred gradually over several interglacial-glacial cycles or abruptly at ∼900 ka. We address these issues using a north-to-south reconstruction of the Atlantic arm of the global meridional overturning ocean circulation, a primary means for distributing heat around the globe, using neodymium (Nd) isotopes. Results reveal a period of intense erosion affecting the cratonic shields surrounding the North Atlantic between Marine Isotope Stages (MIS) 27 and 25 (∼980 and 950 ka), reflected by unusually low Nd isotope ratios in deep North Atlantic seawater. This episode preceded a major ocean circulation weakening between MIS 25 and 21 (950 and 860 ka) that coincided with the first ∼100-ky-long interglacial-glacial onset of Northern Hemisphere glaciation at around 2.4 to 2.8 Ma. The data point to a Northern Hemisphere-sourced initiation for the transition, possibly induced through regolith loss and increased exposure of the crystalline bedrock, which would lead to increased friction, enabling larger ice sheets that are characteristic of the 100-ky interglacial-glacial cycles. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	AMOC structure; Mid-Pleistocene Transition; Nd isotopes; Paleocirculation; Regolith hypothesis
语种	英语
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/238306
作者单位	Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States; Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, United States; Department of Earth and Ocean Dynamics, University of Barcelona, Barcelona, 08028, Spain; MARUM-Center for Marine Environmental Sciences, University of Bremen, Bremen, D-28359, Germany
推荐引用方式 GB/T 7714	Yehudai M.,Kim J.,Pena L.D.,et al. Evidence for a Northern Hemispheric trigger of the 100,000-y glacial cyclicity[J],2021,118(46).
APA	Yehudai M..,Kim J..,Pena L.D..,Jaume-Segui M..,Knudson K.P..,...&Goldstein S.L..(2021).Evidence for a Northern Hemispheric trigger of the 100,000-y glacial cyclicity.Proceedings of the National Academy of Sciences of the United States of America,118(46).
MLA	Yehudai M.,et al."Evidence for a Northern Hemispheric trigger of the 100,000-y glacial cyclicity".Proceedings of the National Academy of Sciences of the United States of America 118.46(2021).