THERMAL-KINEMATIC MODELING OF MULTI-SYSTEM DETRITAL THERMOCHRONOLOGIC DATA FROM ACTIVE CATCHMENTS AS A RECONNAISSANCE TOOL FOR UNDERSTANDING LONG-TERM REGIONAL EROSION PATTERNS

Thermochronology has become an essential tool for reconstructing the long-term exhumation histories of orogenic systems. In recent years, with the development or refinement of isotopic and fission-track thermochronometers sensitive to cooling through a broad range of closure temperatures, we are now able to constrain the cooling histories of individual bedrock samples in unprecedented detail. Through sophisticated 1-D, 2-D, and 3-D thermal-kinematic modeling of such data for samples collected across a tectonic landscape, it is possible to constrain regional patterns in exhumation rate that, in turn, can provide fundamental information regarding regional tectonics. However, such work is time- and labor-intensive, requiring not only the collection of many samples in sometimes rugged terrain, but also extensive sample preparation and painstaking mineral separation. Recent innovations in the use of laser microprobe technologies to rapidly date large numbers of detrital crystals from modern catchments offer an alternative approach that results in catchment-averaged cooling histories across a tectonic landscape, which can be converted effectively to exhumation histories using thermal-kinematic models. While such modeled exhumation histories should only be considered approximate, the efficiency of this approach make it well suited for rapid characterization of exhumation history patterns over large regions when bedrock data are sparse. In addition, such studies can guide more detailed, geographically restricted studies using both bedrock samples and detrital samples from tributary catchments. Here we provide examples of how this approach might be implemented.