The Interdependence of Deformational and Thermal Processes in Mountain Belts

Crustal temperatures within collisional orogens are anomalously high compared with temperatures at comparable depths in stable continents, which is evidence of thermal processes that are fundamental to orogenesis. These temperatures can be explained by the redistribution of crust enriched in heat-producing elements through the accretion of crust from the down-going plate to the upper plate and surface erosion. With the use of geologically reasonable rates, the model results predict high temperatures (over 600°C) and inverted upper-plate geotherms (about 100°C over 20 kilometers) at shallow depths (20 to 40 kilometers) by 25 to 35 million years after collision. This study emphasizes the interdependence of deformational, surficial, and thermal processes.