DOI: 10.1016/j.quascirev.2015.02.009
Scopus记录号: 2-s2.0-84924086187
论文题名: The Southern Glacial Maximum 65,000 years ago and its Unfinished Termination
作者: Schaefer J.M. ; Putnam A.E. ; Denton G.H. ; Kaplan M.R. ; Birkel S. ; Doughty A.M. ; Kelley S. ; Barrell D.J.A. ; Finkel R.C. ; Winckler G. ; Anderson R.F. ; Ninneman U.S. ; Barker S. ; Schwartz R. ; Andersen B.G. ; Schluechter C.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2015
卷: 114 起始页码: 52
结束页码: 60
语种: 英语
英文关键词: Cosmogenic nuclides
; Ice ages
; Last Glacial Maximum
; Marine Isotope Stage 4
; Moraines
; Paleoclimate
; Surface exposure dating
; Terminations
Scopus关键词: Climate change
; Earth (planet)
; Earth atmosphere
; Glaciers
; Greenhouse gases
; Ice
; Isotopes
; Orbits
; Cosmogenic nuclides
; Ice age
; Last Glacial Maximum
; Marine isotope stages
; Moraines
; Paleoclimates
; Surface exposure dating
; Terminations
; Glacial geology
; climate variation
; greenhouse gas
; ice sheet
; Last Glacial Maximum
; meltwater
; orbital forcing
; Pleistocene
; simulation
; New Zealand
英文摘要: Glacial maxima and their terminations provide key insights into inter-hemispheric climate dynamics and the coupling of atmosphere, surface and deep ocean, hydrology, and cryosphere, which is fundamental for evaluating the robustness of earth's climate in view of ongoing climate change. The Last Glacial Maximum (LGM, ~26-19ka ago) is widely seen as the global cold peak during the last glacial cycle, and its transition to the Holocene interglacial, dubbed 'Termination 1 (T1)', as the most dramatic climate reorganization during this interval. Climate records show that over the last 800ka, ice ages peaked and terminated on average every 100ka ('100ka world'). However, the mechanisms pacing glacial-interglacial transitions remain controversial and in particular the hemispheric manifestations and underlying orbital to regional driving forces of glacial maxima and subsequent terminations remain poorly understood.Here we show evidence for a full glacial maximum in the Southern Hemisphere 65.1±2.7ka ago and its 'Unfinished Termination'. Our 10Be chronology combined with a model simulation demonstrates that New Zealand's glaciers reached their maximum position of the last glacial cycle during Marine Isotope Stage-4 (MIS-4). Southern ocean and greenhouse gas records indicate coeval peak glacial conditions, making the case for the Southern Glacial Maximum about halfway through the last glacial cycle and only 15ka after the last warm period (MIS-5a). We present the hypothesis that subsequently, driven by boreal summer insolation forcing, a termination began but remained unfinished, possibly because the northern ice sheets were only moderately large and could not supply enough meltwater to the North Atlantic through Heinrich Stadial 6 to drive a full termination. Yet the Unfinished Termination left behind substantial ice on the northern continents (about 50% of the full LGM ice volume) and after another 45ka of cooling and ice sheet growth the earth was at inter-hemispheric Last Glacial Maximum configuration, when similar orbital forcing hit maximum-size northern ice sheets and ushered in T1 and thus the ongoing interglacial. This argument highlights the critical role of full glacial conditions in both hemispheres for terminations and implies that the Southern Hemisphere climate could transition from interglacial to full glacial conditions in about 15,000 years, while the Northern Hemisphere and its continental ice-sheets required half a glacial cycle. © 2015 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59968
Appears in Collections: 过去全球变化的重建
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作者单位: Lamont-Doherty Earth Observatory, Geochemistry, Palisades, NY, United States; Columbia University, Department of Earth and Environmental Sciences, New York, NY, United States; University of Maine, Department of Earth Sciences and Climate Change Institute, Orono, ME, United States; Victoria University of Wellington, Wellington, New Zealand; SUNY Buffalo, Department of Geology, Buffalo, NY, United States; GNS Science, Dunedin, New Zealand; University of California, Berkeley, Department of Earth and Planetary Sciences, Berkeley, CA, United States; University of Bergen, Department of Earth Sciences, Bergen, Norway; Cardiff University, School of Earth and Ocean Sciences, Cardiff, United Kingdom; University of Oslo, Department of Geology, Oslo, Norway; Institute for Geological Sciences and Oeschger Center for Climate Change Research, Universität Bern, Bern, Switzerland
Recommended Citation:
Schaefer J.M.,Putnam A.E.,Denton G.H.,et al. The Southern Glacial Maximum 65,000 years ago and its Unfinished Termination[J]. Quaternary Science Reviews,2015-01-01,114