Uniform climate development between the subtropical and subpolar Northeast Atlantic across marine isotope stage 11 J. P. Helmke1,*, H. A. Bauch1,2, U. Röhl3, and E. S. Kandiano1 1Leibniz Institute of Marine Sciences, Wischhofstr. 1–3, 24148 Kiel, Germany 2Academy of Sciences, Humanities and Literature, Geschwister-Scholl-Str. 2, 55131 Mainz, Germany 3University of Bremen, Postfach 330440, 28334 Bremen, Germany *now at: Helmholtz Centre for Environmental Research – UFZ, Permoserstr. 15, 04318 Leipzig, Germany
Abstract. Proxy records from a core site off Northwest Africa were generated and
compared with data from the subpolar Northeast Atlantic to unravel some main
climatic features of interglacial marine isotope stage (MIS) 11 (423–362 ka).
The records point to an almost 25 kyr lasting full interglacial period
during stage 11 that was preceded by a considerably long
glacial-interglacial transition (Termination V). Off NW Africa, a strong
reduction of terrestrially derived iron input is noted after 420 ka
suggesting a pronounced increase in continental humidity and vegetation
cover over Northwest Africa. In analogy to the Holocene climate of the
region, this early wet phase of MIS 11 was likely associated with enhanced
influence of the West African monsoon system on the Saharan-Sahel region
which led to both a reduction in trade wind intensity off NW Africa and the
formation of sapropel S11 in the Mediterranean Sea. A detailed comparison
with data from the subpolar North Atlantic indicates a remarkable coherent
timing for the main environmental changes in both regions giving evidence
for strong interglacial climate connection between the low and high latitude
North Atlantic. Although our records of MIS 11 compare well with the
Holocene in terms of some major climate characteristics there are distinct
differences in the temporal evolution of each peak warm interval. This
suggests that care should be taken when using MIS 11 as analogue to forecast
future interglacial conditions.
Citation: Helmke, J. P., Bauch, H. A., Röhl, U., and Kandiano, E. S.: Uniform climate development between the subtropical and subpolar Northeast Atlantic across marine isotope stage 11, Clim. Past, 4, 181-190, doi:10.5194/cp-4-181-2008, 2008.