Geochemical and Dynamical Evolution of the Calapagos Hotspot

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This is a project to continue the sampling and geochemical analysis of Galapagos lavas to the off-shore regions of the platform in order to define the nature of the Galapagos hotspot. Sampling, analysis and dating, combined with the analysis of gravity data, will permit the testing of the thermal entrainment of Mid-ocean Ridge basalt material into the center of the Galapagos plume. %%% One of the most interesting problems in understanding the geochemistry of rocks emplaced on the sea floor is the determine the nature of the interaction between processes that generate basaltic rocks that are found in a normal ocean ridge axis environment and process associated with deep seated hot spot plumes in the mantle. Preliminary study of rocks from the Galapagos platform show that rocks from the interior of the platform look like normal mid ocean ridge basalts, whereas those on the margins of the platform have compositions resembling plumes-type rocks. This rock sampling and analytical program will help test an interesting hypothesis developed by geophysicists regarding the dynamics of plumes that can give rise to the unusual geochemical signature. The personnel for this project are most appropriate because Dr. Christie has considerable experience at sea, Dr. McBirney has done considerable work on the Galapagos Islands, Dr. Richard has developed the hypothesis that is being tested. Drs. Duncan and White provide the necessary analytical expertise.