Reconstructing geologic histories of volcanic fields on Earth and Mars

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The style, timing, distribution, and composition of small-volume basaltic volcanic eruptions are influenced by the climate and tectonic regime in which they form. The proposed research program investigates clusters of diverse volcanoes and volcanic rocks on both Earth and Mars. Gusev Crater, Mars The Mars Exploration Rover Spirit has discovered diverse volcanic and hydrothermally altered rocks. A technique is needed to differentiate primary rock compositions from overprinting alteration. Once rock compositions are deconvolved, they may be used to correlate layered units, alteration conditions, and the mapping of local alteration gradients in order to unravel the magmatic and aqueous history of Mars. Terrestrial volcanic fields I propose to investigate the lifespan, eruption rates, and compositional variability of volcanism in Fort Rock-Christmas Lake (FRCL Basin) in Oregon and in Red Hill Volcanic Field (RHVF) in New Mexico by geologic mapping, whole rock geochemistry, and 40Ar/39Ar geochronology. The timing and alteration of hydrovolcanism will give indication of past climate. Whole rock compositions and petrologic modeling will give insight to mantle melting in back arc setting and heterogeneity and assimilation rates of the upper (lithospheric) mantle.