Funds from this Major Research Instrumentation (MRI) grant will support the acquisition of a state-of-the-art electron microprobe for the Institute for Crustal Studies and Department of Earth Sciences at the University of California Santa Barbara. The new EMP will serve a broad range of NSF funded research that will be advanced by the capability for submicron compositional imaging of natural materials. PI studies of the uplift history of orogens that rely on precision geothermobarometric techniques, and studies of continental crustal genesis, magma chamber dynamics and evolution, and microbial-mineral interactions will all benefit from a state-of-the-art electron probe. Broader impacts include graduate student training and the regional impact of a new EMP facility in the populous southern California region.