GLOW Tropical temperature history during Palaeogene global warming events

The Cenozoic represents a period during which the Earth¿s climate system switched from a warm, greenhouse to a cold, icehouse world. Several rapid global warming events occurred during the in general already warm Paleogene (e.g., Zachos, Kroon et al., 2004; Lourens et al., 2005). Central in this proposal is better understanding of processes that underlie such switches of the climate system at long- and short timescales. Specifically, we aim to document the response of the West Indian Ocean system to these kind of global climate changes, e.g. the biogeochemical state of the western Indian Ocean, the variability of the sea surface temperatures and evolution of biota. These Paleogene intervals of extreme warmth are of significant societal interest; resolving temperature and climate feedbacks will provide valuable insights into possible future climate patterns and biogeochemical state of the ocean. Here, we propose to extend the onshore Tanzanian drilling transect (Nicholas et al., in press) to offshore to complete this transect from shallow environments to the deep sea. We aim to perform a site survey offshore Tanzania to obtain a grid of seismic lines which can subsequently be used in an IODP drilling proposal and/or IMAGES proposal to optimize choice of multiple borehole locations and/or giant piston cores along a depth transect. The seismic profiles, combined with drilling on a subsequent IODP leg, give us the opportunity to draw together existing but disparate fragments of onshore evidence and integrate them with new offshore data to build a comprehensive tectonic, stratigraphic and sedimentological framework for the geological evolution of the southern Tanzanian continental margin from the Permian to Recent.