DOI: 10.1016/j.palaeo.2012.12.018
论文题名: Multiproxy fossil comparison reveals contrasting surface ocean conditions in the western Iceland Sea for the last two interglacials
作者: Van Nieuwenhove N. ; Bauch H.A. ; Andruleit H.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 370 起始页码: 247
结束页码: 259
语种: 英语
英文关键词: East Greenland Current
; Holocene
; Irminger Current
; Last Interglacial
; Nordic seas
; Planktic microfossils
英文摘要: Dinoflagellate cyst (dinocyst), coccolith and planktic foraminiferal assemblages from a core in the western Iceland Sea were used to reconstruct and compare the surface ocean developments of the Holocene and the Last Interglacial (Marine Isotopic Stage or MIS 5e). While increasing subpolar planktic foraminifers from ~. 10. ka indicate subsurface warming peaking around 7.5. ka, the dinocyst data suggest that the uppermost ocean remained dominated by cold waters until ~. 6.5. ka. A reduced advection of cold polar waters through the East Greenland/East Icelandic Current thereafter entailed warmest and most saline Holocene conditions between 6.5 and 5. ka, in turn followed by a general cooling trend. By contrast, both planktic foraminifers and dinocysts show an increased presence of Atlantic (-type) waters from ~. 122. ka onward resulting in a MIS 5e thermal optimum around 120.5. ka. Nonetheless, occasional freshwater input from melting drift ice created stratified but also seasonally variable conditions during this first half of MIS 5e. This stratification signature disappeared at ~. 120. ka when a marked repositioning of the oceanographic fronts occurred. Slightly colder conditions are indicated by both phyto- and zooplankton from there on until the end of MIS 5e around ~. 117. ka. A late MIS 5e cooling at the Iceland Plateau is opposite to a late MIS 5e optimum observed in the eastern Nordic seas. This regional difference is likely explained by various feedback mechanisms following the major reorganisation of the oceanic fronts at ~. 120. ka. The Holocene and MIS 5e interglacial variability is not reflected in the (quasi-monospecific) coccolith assemblages and illustrates the low sensitivity of living coccolithophore communities to subtle temperature changes in the low-temperature regions of the Nordic seas. Overall, quite different surface water properties appear to have characterised both interglacial intervals, with a higher share of warm, Atlantic elements in the planktic communities during MIS 5e. This suggests a higher contribution of Atlantic waters in the southwestern Nordic seas probably due to a more northward expansion of the Irminger Current under weakened polar East Greenland/East Icelandic currents. Such a reduced influence of polar waters in the southwestern Nordic seas may thus explain other evidence for relatively warm conditions in MIS 5e all around southern Greenland. © 2012 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69855
Appears in Collections: 过去全球变化的重建
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作者单位: GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany; GEOTOP, Université du Québec à Montréal, 201 Avenue Président-Kennedy, Montréal, QC, H2X 3Y7, Canada; Mainz Academy of Sciences, Humanities and Literature, Geschwister-Scholl-Str. 2, 55131 Mainz, Germany; Bundesanstalt für Geowissenschaften und Rohstoffe, Stilleweg 2, 30655 Hannover, Germany
Recommended Citation:
Van Nieuwenhove N.,Bauch H.A.,Andruleit H.. Multiproxy fossil comparison reveals contrasting surface ocean conditions in the western Iceland Sea for the last two interglacials[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,370