QUANTITATIVE INTEGRATION OF DIVERSE DATA TO CONSTRAIN UPLIFT, EXHUMATION, AND DEFORMATION IN COMPRESSIONAL OROGENS

The burial and exhumation history of a fold-thrust belt is recorded in the peak temperatures, thermochronologic cooling ages, basin thickness, depositional ages and provenance indicators, detrital cooling ages, and by geomorphic uplift indicators. Typically, one or two of these metrics are used in combination with geologic mapping, potentially with cross-section estimates of subsurface geometry, to draw regional conclusions about the timing, magnitude, and mechanisms of exhumation and deformation, focusing on either the bedrock or foreland basin exhumation records. While each of these datasets provide insight into a component of deformation and associated exhumation, they are limited by available exposure, sample distribution and quality, closure temperature ranges, and the potential for spatial and temporal averaging, and can lead to contrasting interpretations of a single exhumation history. Integrating multiple datasets can bypass the limitations inherent to each approach and provide better insight into the tectonic processes influencing the growth of compressional orogens. We present an approach that integrates the aforementioned metrics with thermokinematic models of a sequentially deformed cross-section that calculates the subsurface thermal field to predict time-temperature pathways and cooling ages for rocks at the surface, using a transect from far western Nepal. Requiring model results to reproduce measured peak temperatures, cooling ages, and locations of active uplift indicated by geomorphic indices provides a means to test the viability of proposed geometries, kinematic sequences, and shortening rates, as well as highlights how these components need to be changed to find the best fit of predicted to measured data. Measured basin thicknesses, depositional ages, and detrital cooling ages further constrain the timing of fault motion, as shortening rate changes that may not alter bedrock cooling ages can affect the depositional and detrital cooling ages of foreland strata. This approach can better resolve geometries, location and rates of uplift, and the associated spatial and temporal changes; test proposed relationships between bedrock and basin records; and resolve outstanding questions on the timing and magnitude of fault displacement and mechanism of deformation.