The geologic interpretation of the detrital thermochronology record within a stratigraphic framework, with examples from the European Alps, Taiwan and the Himalayas

Detrital thermochronology studies based on the lag-time approach are increasingly employed to investigate the erosional evolution of mountain belts and perform paleotectonic reconstructions starting from the analysis of sedimentary rocks. However, simple predictions of lag-time conceptual models are often in conflict with observations in sedimentary basins. In this review article, we discuss the major assumptions of the lag-time approach, and present conceptual models to illustrate the main factors that may influence the final complexity of the detrital thermochronologic record in a sedimentary basin. These factors include: (i) the original complexity of the thermochronologic age structure in the source region; (ii) mixing of detritus from multiple source regions characterized by different geologic evolution; (iii) modifications of the original thermochronologic fingerprint from source to sink; (iv) potential post-depositional annealing due to thick sedimentary burial. Based on this synthesis and discussion, we present a list of interpretive guidelines and fundamental criteria for the geologic interpretation of the detrital thermochronologic record derived from the erosion of single and mixed sources. These interpretive guidelines are then applied to published detrital thermochronology datasets from the European Alps, Taiwan and the Himalayas in order to illustrate benefits and pitfalls of the geologic interpretation of thermochronologic age trends through a stratigraphic succession. Results provide evidence for (i) non-steady-state exhumation of the European Alps, (ii) late Miocene onset of arc-continent collision in Taiwan, and (iii) late Miocene morphogenic phase of mountain building in the Himalaya. Concepts presented in this article reinforce existing approaches and provide new perspectives for the application of the detrital thermochronologic approach to tectonic settings where the geologic evolution may be poorly understood. As such, they are expected to guide geologists towards interpretations that are both consistent with evidence provided by different thermochronologic systems, and geologic evidence provided by the rock record.