DOI: 10.1016/j.quascirev.2013.12.010
Scopus记录号: 2-s2.0-84900427659
论文题名: Oceanographic regimes in the northwest Labrador Sea since Marine Isotope Stage 3 based on dinocyst and stable isotope proxy records
作者: Gibb O.T. ; Hillaire-Marcel C. ; de Vernal A.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2014
卷: 92 起始页码: 269
结束页码: 279
语种: 英语
英文关键词: Dinoflagellate cysts
; Foraminiferal stable isotopes
; Labrador Sea
; Late Pleistocene
; Sea ice
; Sea surface conditions
Scopus关键词: Atmospheric temperature
; Glacial geology
; Isotopes
; Sea ice
; Surface waters
; Dinoflagellate cysts
; Labrador Sea
; Late Pleistocene
; Sea-surface conditions
; Stable isotopes
; Oceanography
; core analysis
; dinoflagellate cyst
; foraminifera
; Glacial Lake Agassiz
; Laurentide Ice Sheet
; marine isotope stage
; North Atlantic Deep Water
; paleoceanography
; paleoclimate
; Pleistocene
; proxy climate record
; reconstruction
; sea ice
; sea surface salinity
; sea surface temperature
; seasonal variation
; stable isotope
; warming
; Atlantic Ocean
; Canada
; Hudson Strait
; Labrador Sea
; Dinophyceae
; Neogloboquadrina pachyderma
英文摘要: Sea surface temperature (SST), salinity and density gradients in the upper water column of the northwest Labrador Sea have been reconstructed based on high resolution analysis of a core (HU2008-029-004PC) spanning the last ~36ka, raised off Hudson Strait. The modern analogue technique was applied to dinocyst assemblages and combined with stable isotope data from Neogloboquadrina pachyderma left-coiled (Npl) for this purpose. Three oceanographic regimes were identified, broadly corresponding to the "glacial", "deglacial" and "postglacial" intervals. The site remained under the direct influence of the Laurentide Ice Sheet (LIS) margin until the postglacial and did not record the Bølling-Allerød warming and weakly recorded the Younger Dryas event. The "glacial" regime lasted until ~12.2calkaBP. It was characterized by generally low concentrations of dinocysts within an assemblage indicative of quasi-perennial sea ice. The "deglacial" regime (ca12.2-8.3calkaBP) was marked by increased biogenic fluxes and more diversified dinocyst assemblages and possibly an enhanced subsurface inflow of North East Atlantic Deep Water. Warm summer (~11°C) but low winter (~0°C) sea surface temperatures, sea ice cover during about 3 months per year, and low summer salinity (~28) suggest strong stratification in the upper water layer in relation to meltwater supply from the LIS. Following the final drainage of glacial Lake Agassiz through Hudson Strait, which is dated here at ~8.3calkaBP, and the subsequent LIS collapse, increased summer salinity (up to ~35) was accompanied by a reduced seasonal gradient of sea surface temperature from winter (~3.8°C) to summer (~8.6°C) suggesting enhanced penetration of North Atlantic Water. Weakened stratification of the surface water layer then allowed for winter convection and Labrador Sea Water formation, which is consistent with increased Npl-δ13C values in response to higher ventilation of the subsurface water layer. © 2013 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60302
Appears in Collections: 过去全球变化的重建
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作者单位: GEOTOP Research Center, CP. 8888 Succ Centre Ville, Montréal, QC H3C 3P8, Canada
Recommended Citation:
Gibb O.T.,Hillaire-Marcel C.,de Vernal A.. Oceanographic regimes in the northwest Labrador Sea since Marine Isotope Stage 3 based on dinocyst and stable isotope proxy records[J]. Quaternary Science Reviews,2014-01-01,92