Collaborative Research: Investigating Initiation and History of the Aleutian Arc and Composition and Significance of North Pacific Seafloor via Dredge Samples from the R/V Sonne

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Subduction is a fundamental tectonic process that shapes the Earth's physical and chemical evolution and has many important potential human impacts, including seismic and volcanic hazards, as well as mineral resources, which are common products of subduction magmatism. As a result, subduction-related processes are the subject of broad public interest and widespread investigation in the geosciences. Despite almost a century of research on the Alaska-Aleutian subduction system, several key questions remain unanswered including how and when the subduction zone was formed and to what extent the subducting Pacific plate contributes to the creation of magma generated beneath Alaska-Aleutian volcanoes. This project will allow a group of U.S. scientists from the University of South Carolina and the University of Wisconsin-Madison to precisely determine the timing of Aleutian arc formation and to characterize the products that are entering and have erupted from this active volcanic arc. This is a collaborative effort involving graduate and undergraduate students, post-docs, and researchers from Germany, Russia and the United States. All data from this project will be made available to the public. The project has two broadly related themes: 1) Constraining the timing of subduction initiation and early evolution of the Aleutian arc, and 2) Characterizing subduction inputs to both the Aleutian and Kamchatka arcs and relating them to the processes controlling arc magma formation. Analyses of samples from Expedition SO249 of the German R/V Sonne as part of the German-Russian BERING project will provide constraints on the timing of Aleutian arc formation and the geochemistry of the early arc products. The project will also obtain geochemical data for north Pacific seafloor samples adjacent to the western Aleutian arc, including sites both east and west of the northern Emperor seamounts. This study will help better understand geochemical linkages between subduction input and volcanic output, and will provide new constraints and significantly improve models of arc magma genesis for the Aleutians and Kamchatka.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.