Funds are provided to continue geochemical and tectonic investigations of the eastern Galapagos Rift and southern Juande Fuca Ridge including: Axial volcano, the Cleft and Vance segments of the Juan de Fuca Ridge (JDF) and the Vance seamount chain. Studies on samples from the Galapagos recovered during a 1988 AII/ALVIN cruise will be completed. PI will also participate in a 1990 field program along the southern JDF Ridge. The results of these investigations, integrated with available geophysical and geological data, will provide the basis for comprehensive models of the tectonomagmatic and hydrothermal processes that occur along these ridge segment sand their associated seamounts. These studies include the lava types and their marphology; chemical variability of Mid Ocean Ride Basalts and the role of magma mixing, crystal fractionation and crustal assimitation; chemical characteristic of axial volcano and seamount lavas and magna chamber processes.
