Collaborative Research: RUI: The Effect of a Mid-Ocean Ridge-Centered Environment on a Zoned Mantle Plume and Associated Secondary Magmatism

Ithaca College, Ithaca NY

Investigators

Abstract

Volcanic ocean islands are of wide interest. Placed far from the influence of continents, their flora and fauna followed unique evolutionary pathways and their tall volcanoes rising from the seafloor create extraordinary marine ecosystems. Their volcanoes are generated from long-lived rising plumes of hot mantle. The lavas that erupt to form these islands contain geochemical clues about long-term movements of the mantle. Each volcano eventually becomes extinct as it is transported away from its source plume by tectonic plate motion, eventually subsiding below the sea surface. In this study, lavas previously recovered from the now drowned part of the Galapagos island chain that formed between 5 and 10 million years ago will be analyzed for age and geochemical composition. The proposed work will test models of how mantle plume composition and melting can change over space and time. The work will also investigate mechanisms of volcanism that occur away from the mantle plume. This is a joint project between Ithaca College and Colgate University in collaboration with GEOMAR (Kiel, Germany). The project invests directly in undergraduate research experiences. The students will develop skills such as conducting a search for background information, discussing/focusing research questions, learning new analytical techniques, learning about data quality control, and managing datasets. In this study, the age and composition of lavas recovered from the Eastern Galápagos Platform and Carnegie Ridge (EGPCR) will be analyzed for their age and composition. These features represent the 5-10 Ma portion of the thickened oceanic crust on the Nazca plate created when the Galápagos plume was located directly below the Galápagos Spreading Center. The primary goal of this project is to use the EGPCR data to address global questions about plume structure and dynamics and the extent of secondary magmatism after plume-related magmatism has ceased. The activities for this proposed study will focus on high resolution 40Ar-39Ar radiometric dating and major, trace, and Sr-Nd-Pb-Hf isotopic ratio analysis of existing rocks recovered from the region. This project invests directly in undergraduate research experiences where four undergraduate students from Ithaca College and Colgate University will perform laboratory work during the summers and continue during the academic year. The project also enhances international cooperation with the involvement of at GEOMAR in Kiel, Germany. 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.