Age2exhume: A Matlab/Python script to calculate steady-state vertical exhumation rates from thermochronologic ages in regional datasets

Interpreting cooling ages from multiple thermochronometric systems and/or from steep elevation transects with the help of a thermal model can provide unique insights into the spatial and temporal patterns of rock exhumation. Several well-established thermal models allow for a detailed exploration of how cooling or exhumation rates evolved in a limited area or along a transect. However, integrating large, regional datasets in such models remains challenging due to the difficulty of extracting exhumation rates from ages that are affected by variable effective cooling temperatures, sampling elevations, and surface temperatures. Here we present a thermal model that can be used to rapidly provide a synoptic overview of exhumation rates from thermochronologic data spread over wide regions. The model incorporates surface temperature based on a defined lapse rate and sample elevation relative to a mean relief value that is dependent on the thermochronometric system of interest. Other inputs include sample age, thermochronometric system, and an initial (unperturbed) geothermal gradient. The model is simplified in that it assumes steady, vertical rock-uplift when calculating exhumation rates. For this reason, it does not replace more powerful and versatile thermal-kinematic models like PECUBE, but it has the advantage of simple implementation and rapidly calculated results. In our example dataset, we show the results of exhumation rates calculated from 1785 thermochronologic ages from the Himalaya associated with five different thermochronometric systems; results were calculated in under a second on a standard laptop. Despite the synoptic nature of the results, we show how they illustrate several fundamental features of the mountain belt, including strong regional differences that reflect known segmentation patterns and changing exhumation rates in areas of newly developed ramp structures. The results can also be correlated with geomorphic metrics to probe potential controls on surface morphology.