气候变化领域集成服务门户(CCPortal): In situ cosmogenic 10Be-14C-26Al measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size

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DOI	10.5194/cp-17-419-2021
	In situ cosmogenic 10Be-14C-26Al measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size
	Young N.E.; Lesnek A.J.; Cuzzone J.K.; Briner J.P.; Badgeley J.A.; Balter-Kennedy A.; Graham B.L.; Cluett A.; Lamp J.L.; Schwartz R.; Tuna T.; Bard E.; Caffee M.W.; Zimmerman S.R.H.; Schaefer J.M.
发表日期	2021
ISSN	1814-9324
起始页码	371
结束页码	386
卷号	17 期号:1
英文摘要	Sometime during the middle to late Holocene (8.2 ka to ∼ 1850 1900 CE), the Greenland Ice Sheet (GrIS) was smaller than its current configuration. Determining the exact dimensions of the Holocene ice-sheet minimum and the duration that the ice margin rested inboard of its current position remains challenging. Contemporary retreat of the GrIS from its historical maximum extent in southwestern Greenland is exposing a landscape that holds clues regarding the configuration and timing of past ice-sheet minima. To quantify the duration of the time the GrIS margin was near its modern extent we develop a new technique for Greenland that utilizes in situ cosmogenic 10Be 14C 26Al in bedrock samples that have become ice-free only in the last few decades due to the retreating ice-sheet margin at Kangiata Nunaata Sermia (n D 12 sites, 36 measurements; KNS), southwest Greenland. To maximize the utility of this approach, we refine the deglaciation history of the region with stand-alone 10Be measurements (n = 49) and traditional 14C ages from sedimentary deposits contained in proglacial threshold lakes. We combine our reconstructed ice-margin history in the KNS region with additional geologic records from southwestern Greenland and recent model simulations of GrIS change to constrain the timing of the GrIS minimum in southwest Greenland and the magnitude of Holocene inland GrIS retreat, as well as to explore the regional climate history influencing Holocene ice-sheet behavior. Our 10Be 14C 26Al measurements reveal that (1) KNS retreated behind its modern margin just before 10 ka, but it likely stabilized near the present GrIS margin for several thousand years before retreating farther inland, and (2) pre-Holocene 10Be detected in several of our sample sites is most easily explained by several thousand years of surface exposure during the last interglaciation. Moreover, our new results indicate that the minimum extent of the GrIS likely occurred after ∼ 5 ka, and the GrIS margin may have approached its eventual historical maximum extent as early as ∼ 2 ka. Recent simulations of GrIS change are able to match the geologic record of icesheet change in regions dominated by surface mass balance, but they produce a poorer model data fit in areas influenced by oceanic and dynamic processes. Simulations that achieve the best model data fit suggest that inland retreat of the ice margin driven by early to middle Holocene warmth may have been mitigated by increased precipitation. Triple 10Be 14C 26Al measurements in recently deglaciated bedrock provide a new tool to help decipher the duration of smaller-thanpresent ice over multiple timescales. Modern retreat of the GrIS margin in southwest Greenland is revealing a bedrock landscape that was also exposed during the migration of the GrIS margin towards its Holocene minimum extent, but it has yet to tap into a landscape that remained ice-covered throughout the entire Holocene. © 2021 Author(s).
来源期刊	Climate of the Past
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/183604
作者单位	Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States; Department of Earth Sciences, University of New Hampshire, Durham, NH 03824, United States; Department of Earth System Science, University of California Irvine, Irvine, CA 92697, United States; Department of Geology, University at Buffalo, Buffalo, NY 14260, United States; Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, United States; CEREGE, Aix-Marseille University, CNRS, IRD, INRAE, Collège de France, Technopôle de l'Arbois, Aix-en-Provence, France; Department of Physics and Astronomy, PRIME Lab, Purdue University, West Lafayette, IN 47907, United States; Department of Earth Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN 47907, United States; Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States
推荐引用方式 GB/T 7714	Young N.E.,Lesnek A.J.,Cuzzone J.K.,et al. In situ cosmogenic 10Be-14C-26Al measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size[J],2021,17(1).
APA	Young N.E..,Lesnek A.J..,Cuzzone J.K..,Briner J.P..,Badgeley J.A..,...&Schaefer J.M..(2021).In situ cosmogenic 10Be-14C-26Al measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size.Climate of the Past,17(1).
MLA	Young N.E.,et al."In situ cosmogenic 10Be-14C-26Al measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size".Climate of the Past 17.1(2021).