Climate-ocean interactions in the eastern subtropical Cretaceous Atlantic: Integrating long-term and punctuated Late Aptian to Early Albian climate records from the Mazagan Plateau (DSDP Site 545)

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The Late Aptian to Early Albian represents a major transition in mid-Cretaceous tectonics, volcanic activity, climate and marine plankton communities, leading to a cascade of global and local perturbations of the climate-carbon cycle. The goal of this multi-proxy study is to develop complementary climate records in the eastern subtropical Atlantic region (DSDP Site 545) covering a time period of 5 million years. The overall aim is to decipher global and local climate signatures from marine sediments in order to address the underlying driving mechanisms and feedbacks of environmental and climate change. Our results quantify for the first time a long term cooling trend for the Upper Aptian that culminated in a „cold snap‟ by using TEX86-derived sea surface temperature estimates. The „cold snap‟ was associated with changes in the community of carbonate producers. We also recognize three short term temperature events with durations of less than 150 ka, a heating pulse (+4°C) and two cooling pulses (-2° to -2.5°C), which are superimposed onto the long term cooling trend. We tentatively relate short term warming to a (previously unknown) hyperthermal event, and the cooling periods to large scale re-organizations in North Atlantic deep water circulation, possibly related to the opening of oceanic gateways. In project phase two we propose to decipher the global or local aspects of the observed temperature development by studying a complimentary core from the Falkland Plateau (DSDP Site 511, South Atlantic) and by further investigation of the observed short climate pulses at Site 545.