College of Arts and Sciences News
Geology to host Dr. Mimi Katz, 2012 Integrated Ocean Drilling Program LecturerPosted Sep. 24, 2012
The Department of Geology will host Dr. Mimi Katz of the Rensselaer Polytechnic Institute, one of the 2012 Integrated Ocean Drilling Program (IODP) Distinguished Lecturers. Dr. Katz will give two lectures describing Ocean Circulation and Global Climate Change.
Monday, Sept. 24th – Room 234 (2:00-3:30pm)
Antarctic Circumpolar Current Evolution and its Impact on Climate and Global Ocean Circulation The Antarctic Circumpolar Current (ACC) is a dominant feature of modern ocean circulation and climate, influencing global circulation, gas exchange between atmosphere and ocean, and global heat distribution. The impact of the ACC on global systems at its early stages of development has been debated for decades, largely based on analyses of sediments collected by DSDP/ODP/IODP. Major oceanographic events spanning the middle Eocene to Oligocene (~40-24 Ma) are attributed by some researchers to ACC development, whereas others attribute these changes primarily to decreasing atmospheric CO2. Assertions that the ACC had little impact before the late Oligocene (~25 Ma) conflict with proxy records and modelling studies that indicate a shallow, proto-ACC affected some regions much earlier. New comparisons of benthic foraminiferal stable isotope records from multiple ocean basins, along with additional proxies, show that the proto-ACC impacted global ocean circulation and primary production by the late Eocene. The modern four-layer ocean structure (surface, intermediate, deep, bottom) developed during the early Oligocene (~30-31 Ma) as a consequence of the progressive deepening of the ACC. Global cooling and development of continental-scale Antarctic glaciation in the late Eocene-early Oligocene occurred in concert with this deep-sea reorganization, reinforcing the role of the ACC in these events.
Tuesday, Sept. 25th – Room 339 (11:00am-12:00pm)
Deciphering the History of the World's Oceans with Single-Celled Fossils Single-celled microfossils that lived on the seafloor, called benthic foraminifera, have provided much of the foundation for reconstructions of past ocean and climate conditions, including ancient sea-level changes. Different benthic foraminiferal species typically colonize certain water depth ranges, with key depth-indicator species providing an invaluable tool for reconstructing paleobathymetry. The paleodepth history of a site can be determined by documenting benthic foraminiferal changes. Integrated Ocean Drilling Program Expedition 313 drilled a critical nearshore segment of the New Jersey margin transect that extends from the onshore coastal plain to the continental slope. The transect is designed to unravel the complex relationships between global sea level change and margin sedimentation. In conjunction with sediment studies, benthic foraminifera provide the basis to reconstruct past sea-level changes and to decipher the continental margin sedimentation response to sea-level change.