Millennial-scale surface and subsurface paleothermometry from the northeast Atlantic, 55-8 ka BP
Peck, V. L. (Cardiff University. School of Earth and Ocean Sciences)
Hall, Ian R. (Cardiff University. School of Earth and Ocean Sciences)
Zahn, Rainer (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)
Elderfield, Henry (University of Cambridge. Department of Earth Sciences)

Data:	2008
Resum:	We present high-resolution records of upper ocean temperatures derived from Mg/Ca ratios of surface-dwelling Globigerina bulloides and subsurface-dwelling Neogloboquadrina pachyderma sinistral and the relative abundance of N. pachyderma sinistral for the period 55-8 ka BP from NE Atlantic sediment core MD01-2461. Millennial-scale temporal variability and longer-term trends in these records enable us to develop a detailed picture of past ocean conditions such as a weakening of thermocline intensity from marine isotope stage 3 (MIS 3) to the last glacial maximum (LGM). The correspondence of all temperature proxies and convergence of paired oxygen isotope (δ18O) records from both planktonic species implies a breakdown in the thermocline and year-round mixing of the upper water column through the LGM, perhaps related to decreasing insolation and additional cooling in association with the expansion of the circum-North Atlantic ice sheets. Millennial-scale divergence in surface and subsurface temperatures and δ18O across the last glacial correspond to meltwater release and the development of a strong halocline associated with both Heinrich (H) events and instabilities of the NW European ice sheet. During such episodes, G. bulloides Mg/Ca appears to record ambient, even warming summer sea surface temperatures across H events while the other proxies record maximum cooling.
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Publicat a:	Paleoceanography, Vol. 23 Issue 3 (September 2008) , p. 3221, ISSN 1944-9186

DOI: 10.1029/2008PA001631

11 p, 489.0 KB

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