9406253 Hollister It is widely recognized that in the development of many orogenic belts there was a phase of rapid exhumation of hot crystalline rocks, giving rise to nearly isothermal decompression at peak temperature and clockwise PTt paths. Several recent studies in the Himalayas have focused on phases in the development of the Himalayan orogen consisting of high temperature decompression. One of the continuing problems is identifying the heat source for forming the migmatites in the middle crust, and several conflicting models have been proposed. This research is to obtain well constrained metamorphic P-T data and interpretation of P-T-time-deformation paths in order to constrain models pertaining to the question of how migmatite can be formed in or tectonically transported into the middle crust. Results will help understand the common occurrence of rapid exhumation of hot crystalline rocks in the cores of many orogenic zones.
