25th International Meeting on Organic Geochemistry IMOG 2011

P-455
Long term cooling and punctuated climate events recorded in
Late Aptian to Early Albian sediments from the eastern
subtropical Atlantic (Mazagan Plateau, DSDP Site 545)
Alison McAnena 1 , Thomas Wagner 2 , Helen M. Talbot 2 , Jens Herrle 3 , Joerg Pross 3 , Janet
Rethemeyer 1 , Peter Hofmann 1
1 Department of Geology and Mineralogy, University of Cologne, 50674 Cologne, Germany, 2 School of Civil
Engineering and Geosciences, Newcastle University, Newcastle Upon Tyne, NE1 7RU, United Kingdom,
3 Institute of Geosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany (corresponding
author:amcanena@uni-koeln.de)
The Late Aptian-Early Albian reflects a period of
global transition towards the mid-Cretaceous
greenhouse, with heightened tectonic, volcanic and
hydrothermal activity, and an increase in organic
carbon burial in combination leading to a global
adjustment of climate conditions. In order to
document the response of the tropical North Atlantic
to this global climatic readjustment, we investigate the
sea surface temperature development over 5 million
years in the late Aptian expressed in marine
sediments from DSDP Site 545, Mazagan Plateau
(NW Africa).
Detailed new records of TEX86-derived sea surface
temperature (SST), organic carbon (TOC) and
carbonate content, grain size composition, δ 13 Ccarb
and δ 13 Corg confirm a >1.5 Ma cooling trend off NW
Africa that culminated in the Late Aptian ‗cold snap [1] ,
before the onset of OAE 1b. Superimposed on this
long term cooling trend three short term intervals are
identified where surface waters either markedly
cooled or warmed. Notably, these short-term SST
perturbations are stratigraphically linked to small
(