The Geological Sciences Colloquium Series presents Dr. Cathy Busby on “Anatomy of a Long-Lived Oceanic Arc: Synthesis of Three IODP Expeditions in the Izu-Bonin-Marianas Arc” on Friday, March. 31, from 3:05 p.m. to 4:00 p.m. in Clippinger 205.
Dr. Cathy Busby
Dr. Busby is Professor Emerita of Geology in the Department of Earth and Planetary Sciences at the University of California, Davis, where she conducts research. As Professor of Geology at the University of California, Santa Barbara, she taught courses in Field Geology, Sedimentary Geology, Volcanology, and more.
Abstract: This talk provides an overview of results from three closely related IODP expeditions carried out in sequence in the Izu-Bonin-Mariana (IBM) arc system in 2014. It focuses on geologic results that are of interest to those working in magmatic arcs on continents as well as those in the sea. Expedition 350 was the first expedition to drill in the Izu rear arc; all previous IODP sites were drilled in or near the Izu-Bonin arc front or fore arc, leading to an incomplete view of Izu arc magmatism. Thus, the main objective of Expedition 350 was to reveal the history of “the missing half” of the subduction factory. The second expedition (351) focused on IBM arc origins by drilling west of the Kyushu-Palau remnant arc ridge, where the foundation, origin, and early evolution of the IBM arc is recorded. The third expedition (352) examined the processes of subduction initiation, by drilling the outer IBM fore arc. My talk will describe the Paleogene to Neogene evolution of the IBM arc system, and compare it with outcrop analogs, with the goal of constructing an Island Arc Crust Virtual Field Model.
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