DOI: 10.1016/j.epsl.2018.07.038
Scopus记录号: 2-s2.0-85051405656
论文题名: Last Glacial Maximum surface water properties and circulation over Laurentian Fan, western North Atlantic
作者: Gil I.M. ; Keigwin L.D.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 500 起始页码: 47
结束页码: 55
语种: 英语
英文关键词: detrital events
; diatoms
; ice rafted debris
; Last Glacial Maximum
; Laurentide ice sheet
; subglacial flows
Scopus关键词: Glacial geology
; Glaciers
; Ice
; Oceanography
; Phytoplankton
; Surface waters
; detrital events
; diatoms
; Ice rafted debris
; Last Glacial Maximum
; Laurentide ice sheets
; Subglacial flows
; Sediments
; detrital deposit
; diatom
; Heinrich event
; ice-rafted debris
; Last Glacial Maximum
; Laurentide Ice Sheet
; subglacial environment
; surface water
; Atlantic Ocean
; Gulf of Saint Lawrence
; Laurentian Channel
; Bacillariophyta
; Foraminifera
英文摘要: Millennial scale events marked by the contribution of detrital sand are recorded in North Atlantic sediments during the Last Glacial Maximum (LGM), between Heinrich events (HE) 1 and 2, and left their imprint on Laurentian Fan (LF – 43°N) sediments off eastern Canada. The LF counterpart of the well-known detrital events consist of glacial red-brick sediments resulting from subglacial flows separated by olive-grey sediments appears at ∼21.4–19.9 and ∼19.5–18.65 cal kyr BP. High-resolution analyses of diatom assemblages and lithic grains coupled with planktonic oxygen isotopic records reveal that while the red sediment is almost barren of diatoms, foraminifera and lithics (>150 μm), they are abundant in the olive-grey sediment. Diatom assemblages reveal three phases during these events: (1) initial relatively warm/temperate conditions followed by (2) very cold surface water and drifting ice, and (3) a final phase characterized by relatively warmer waters and the appearance of detrital carbonate. Although these events possibly reflect the variability specific to the slope water region, they are likely the response to Atlantic Meridional Overturning Circulation perturbations and ice-sheet instability. Through a chain of mechanisms, meltwater inputs into the North Atlantic led ultimately to an increased volume of tropical waters and part of the heat stored in the subsurface was flushed by a brief convective episode that was not sustained, accounting for the return of cold conditions after the events. The sequence of mechanisms deduced from the paleo data here and elsewhere is consistent with previous modeling results. These data suggest that the detrital events between Heinrich event 1 and 2 may be synchronous across the North Atlantic, and that the LGM was probably not a time of prolonged steady state in the climate system. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109682
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: IPMA – Portuguese Institute for the Sea and Atmosphere, Marine Geology and Geo-Resources Division, Rua Alfredo Magalhães Ramalho, 6, Lisboa, 1495-006, Portugal; CCMAR – Centre of Marine Sciences, Campus de Gambelas, Faro, 8005-139, Portugal; WHOI – Woods Hole Oceanographic Institution, Geology & Geophysics, 266 Woods Hole Rd. – MS# 08, Woods Hole, MA 02543-1050, United States
Recommended Citation:
Gil I.M.,Keigwin L.D.. Last Glacial Maximum surface water properties and circulation over Laurentian Fan, western North Atlantic[J]. Earth and Planetary Science Letters,2018-01-01,500