DOI: 10.1016/j.quascirev.2017.06.011
Scopus记录号: 2-s2.0-85020854532
论文题名: Age of the Pineo Ridge System: Implications for behavior of the Laurentide Ice Sheet in eastern Maine, U.S.A., during the last deglaciation
作者: Hall B.L. ; Borns H.W. ; Jr. ; Bromley G.R.M. ; Lowell T.V.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2017
卷: 169 起始页码: 344
结束页码: 356
语种: 英语
英文关键词: Exposure-age dating
; Glacial history
; Heinrich Stadial 1
; Laurentide Ice Sheet
; Maine
; North America
; Pineo Ridge
英文摘要: The Laurentide Ice Sheet was a major driver of global sea-level change during the last deglaciation and may have impacted both atmospheric and oceanic circulation. An understanding of past changes in the ice sheet is important for constraining its interaction with other components of the climate system. Here, we present the geologic context and chronology for ice-sheet fluctuations in eastern Maine, adjacent to the North Atlantic Ocean, thought to be a key player in the termination of the last ice age. Retreat of the Laurentide Ice Sheet through coastal Maine first produced a series of lobate grounding-line moraines, followed by deposition of the prominent Pineo Ridge System, which crosscut the earlier moraine set and which is characterized by extensive ice-contact deltas, closely spaced parallel moraines, and association with eskers. Our new 10Be surface exposure ages indicate that the Pineo Ridge System, which extends for more than 100 km in eastern Maine and Atlantic Canada, dates to ∼15.3 ka, ∼800 years older than recent estimates. Our data are in accord with inboard minimum-limiting radiocarbon ages of terrestrial materials, which indicate deglaciation as early as 15.3 ka, as well as of marine shells that are as old as 15.0 ka. Both the deglaciation that produced the lobate moraines and the short-lived readvance that led to the Pineo Ridge System occurred during Heinrich Stadial 1. Given that faunal and isotopic evidence indicates that the ocean remained cold during deglaciation of coastal Maine, we infer that ice recession was due to rising summer air temperatures that gave way briefly to cooling to allow minor readvance. Glacial deposits north of the Pineo Ridge System display evidence of ice stagnation and downwasting, suggesting rapid ice retreat following deposition of the delta-moraine complex, coincident with the onset of the Bølling. © 2017 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59181
Appears in Collections: 过去全球变化的重建
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作者单位: School of Earth and Climate Sciences and the Climate Change Institute, University of Maine, Orono, ME, United States; Department of Geology, University of Cincinnati, Cincinnati, OH, United States
Recommended Citation:
Hall B.L.,Borns H.W.,Jr.,et al. Age of the Pineo Ridge System: Implications for behavior of the Laurentide Ice Sheet in eastern Maine, U.S.A., during the last deglaciation[J]. Quaternary Science Reviews,2017-01-01,169