9526659 Hodges The process of extensional deformation within orogenic belts is of considerable interest in the development of collisional mountain ranges. First well-documented in the Himalaya, these extensional structures appear to provide a mechanism for limiting the topographic relief and mean elevation when physical erosion is not sufficient to compensate for the compression-drives uplift. Commonly associated with these extensional features is an enigmatic metamorphic relationship in which the metamorphic grade is inverted, that is, increases upward. From thermal modeling it is clear that these inverted metamorphic gradients can only be preserved with rapid cooling. However, the temporal spatial and mechanical relationships between deformation (compression with extensional unroofing accommodation) and the geothermal budget (Metamorphic grade and pressure-temperature-time path) of these systems is not well understood. This project will study tectonic denudation and inverted metamorphism in the East Greenland Caledonides. This area exposes a much deeper part of an Orogen, and the inverted metamorphic gradient is present in a different structural setting from analogous structures in the Himalaya. Technically, the high-precision geochronologic techniques to be used are capable of more closely tying deformation metamorphism in this older orogen. The expected results of this research include a better understanding of the thermal behavior of actively deforming orogens, particularly in response to episode of extension in the overall compressional orogens.
