Tectonomagmatic Cycles and the Formation of Oceanic Crust at the Cleft Segment of the Juan de Fuca Ridge

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Under this award, the PI will continue participating in a collaborative study of the Cleft segment of the Juan de Fuca ridge. The field work has been and will continue to be done with MBARI vessels and ROVs, in active collaboration with D. Stakes, M. Tivey, and others. The PI's main responsibility is in sampling of volcanic rocks, interpreting volcanic land forms, and undertaking laboratory analyses of the rock samples. One field program occurred in 2000, and another will take place in 2002. The PI has additional rock samples from the area collected in 1990 and 1994. The PI proposes flow mapping of the axial and off-axis region with a variety of goals and objectives, one of which is to test the "split-ridge" model of Kappel and Ryan for tectonic and magmatic cycles forming the symmetrical land forms on either side of the present ridge axis. Axial and off-axis sampling out to ~6km (150 ka) will be used to test this idea, and elucidate the processes of crust creation and evolution in the near-axis region. A full laboratory program of major and trace element studies and isotopic studies are planned for ROV-collected and wax cored samples.