Cenozoic volcanism in the California Coast Ranges: numerical solutions

Presents the results of numerical simulations of Cenozoic volcanism in the Coast Ranges of California, associated with the northward migration of the Mendocino Triple Junction (MTJ). Three aspects of the thermal evolution and magmatism in the wake of the MTJ are investigated: 1) mantle flow and thermal perturbation in the "slabless window'; 2) pressure-release partial melting in the upwelling asthenosphere; and 3) thermally induced crustal anatexis. Numerical results show that upwelling of asthenosphere in the "slabless window' causes a drastic change in the thermal structure of the lithosphere and results in significant pressure-release partial melting in the upwelling asthenosphere. This work also suggests that the spatial and temporal distribution of Cenozoic volcanism in the California Coastal Ranges is directly related to the variation of the relative velocity between the North America and Pacific plates in the last 30 m.y. -from Authors