气候变化领域集成服务门户(CCPortal): Multiple glacial maxima of similar extent at ∼20–45 ka on Mt. Usborne; East Falkland; South Atlantic region

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DOI	10.1016/j.quascirev.2020.106677
	Multiple glacial maxima of similar extent at ∼20–45 ka on Mt. Usborne; East Falkland; South Atlantic region
	Hall B.L.; Lowell T.V.; Brickle P.
发表日期	2020
ISSN	0277-3791
卷号	250
英文摘要	The pattern, timing, and origin of Southern Hemisphere climate change during the last glaciation remains a pressing problem, with implications for the role of orbital forcing in ice-age cycles. Here, we present geomorphological and cosmogenic exposure age data from East Falkland in the South Atlantic region that show onset of glacial conditions by marine isotope stage 4 (∼60–70 ka), with expansion of ice to its maximum extent of the last glaciation. At least seven geomorphological units marked by multiple crests on composite moraines indicate glacier expansion on Mt. Usborne, the highest peak of East Falkland. From ∼20 to 45 ka, glaciers fluctuated on a millennial timescale with near-maximum conditions being reached repeatedly. Overall ice extent appears to have shrunk slightly through time, with evidence of glaciation at ∼20 ka preserved only in the highest-elevation cirques. This long glacial maximum is inconsistent both with local orbital control and orbital forcing as expressed in the traditional Milankovitch hypothesis. The timing of millennial glacier expansions occurred between Northern Hemisphere Heinrich Stadials and resembles that documented for New Zealand glaciers, suggesting at least a trans-Pacific expression. We postulate that periodic recessions corresponded with southward expansion of the southern westerlies during Heinrich Stadials and warming air and ocean temperatures over the South Atlantic region. © 2020 Elsevier Ltd
英文关键词	10Be exposure age dating; Falkland Islands; Last glacial maximum; South Atlantic
语种	英语
scopus关键词	Climate change; Expansion; Ice; Cosmogenic exposure; Geomorphological units; Local orbitals; Marine isotope stages; Northern Hemispheres; Ocean temperature; Orbital forcing; Southern Hemisphere; Glacial geology; climate variation; geomorphology; Heinrich event; Last Glacial Maximum; last glaciation; marine isotope stage; orbital forcing; Southern Hemisphere; warming; water temperature; westerly; Atlantic Ocean; Atlantic Ocean (South); East Falkland; Falkland Islands (Malvinas); New Zealand
来源期刊	Quaternary Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151225
作者单位	School of Earth and Climate Sciences and Climate Change Institute, University of Maine, Orono, ME, United States; Department of Geology, University of Cincinnati, Cincinnati, OH, United States; South Atlantic Environmental Research Institute, Stanley
推荐引用方式 GB/T 7714	Hall B.L.,Lowell T.V.,Brickle P.. Multiple glacial maxima of similar extent at ∼20–45 ka on Mt. Usborne; East Falkland; South Atlantic region[J],2020,250.
APA	Hall B.L.,Lowell T.V.,&Brickle P..(2020).Multiple glacial maxima of similar extent at ∼20–45 ka on Mt. Usborne; East Falkland; South Atlantic region.Quaternary Science Reviews,250.
MLA	Hall B.L.,et al."Multiple glacial maxima of similar extent at ∼20–45 ka on Mt. Usborne; East Falkland; South Atlantic region".Quaternary Science Reviews 250(2020).