Evaluation of a causal link between ACC development and Cenozoic Antarctic glaciation requires an examination of the temporal coincidence of ice-volume increase, plate tectonic opening of Drake Passage, and the penetration of Pacific-derived seawater into the Atlantic Ocean. Whereas a robust Cenozoic δ¹⁸O benthic marine stratigraphy constrains global ice-volume changes, the history and pattern of tectonic opening of Drake Passage remains elusive, and geochemical tracing of water-mass provenance through Drake Passage has only recently been utilized.

Using existing marine sediment cores supplemented with existing and new outcrop rock samples, we are collecting and integrating ice-volume and marine paleothermometry proxy records with sediment provenance and water-mass provenance data, all collected from common samples of Cretaceous through Miocene marine sediments of the Antarctic Peninsula the Scotia & Weddell Seas and the Patagonia orocline. We are also integrating these multi-component data with thermochronometry of the Antarctic Peninsula and Patagonia orocline, which will allow us to constrain the spatio-temporal distribution of orogenic and ocean circulation proxies that record opening of Drake Passage.

This integrated approach is designed to:

1. determine the history of sedimentary connections and separations between crustal fragments in the Scotia Sea and adjacent continents
2. improve reconstruction of orogenic kinematics in the Patagonian orocline and Antarctic Peninsula that enabled Drake Passage opening and interpreted subsequent Antarctic environmental change
3. constrain the pattern and timing of intrusion of Pacific seawater through the Scotia Sea and into the Atlantic realm as required for set-up of the ACC
4. compare the temporal and spatial relationships between the data collected in (1) – (3) with local and global proxies for Cenozoic ice-volume and deep water temperature changes that appear to have driven middle-Cenozoic Antarctic and global environmental changes.