Petrogenetic Studies of Young Volcanic Rocks

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This is an Accomplishment Based Renewal by an outstanding scientist who is a member of the US National Academy of Sciences and universally acknowledged by members of the marine geology community as one of the leaders in the field. His research, over the past few decades, has transformed our understanding of magmatic process occurring at mid-ocean ridges and convergent margins like Cascadia and the Aleutians in the US and Japan in Pacific. In both volcanic environments, melts arising from the mantle come to the surface and produce the volcanoes and lavas that form the floor of the oceans and island arc volcanic chains. This renewal builds off the investigator's work over the last five years in improving our understanding of seafloor volcanism, including the creation of an internally consistent geochemical and geophysical database for which over 1,000 new high quality major and trace element analyses of seafloor volcanic rocks were collected and then combined with thousands of other similar data collected from the scientific literature. This has provided the essential data needed to test global models of mantle temperature and composition. The new research will allow determination of the relationship between basalt composition and the physical properties and variables of mid-ocean ridges on a global scale; determine the principles that control the extent of mantle melting, compositional fractionation, and magma mixing; identify magma sources and source heterogeneity; and determine the causes of the disconnect between mantle temperatures and lava trace element geochemistry. This work will also involve the creation of a similarly comprehensive geochemical database for ocean island basalts, which can be used with geophysical information such as island size, volume, height above the seafloor, and tectonic plate age and thickness to illuminate the origin and evolution of ocean islands and identify commonalities and global trends. Broader impacts of the work include support of an early career collaborating scientist whose gender is under-represented in the sciences, training of a graduate students, and building infrastructure for science in terms of creating a new comprehensive community dataset that will be publicly accessible and can be used to test and constrain models for the formation and growth of ocean islands over time.