Multi-OSL-thermochronometry of feldspar

Optically stimulated luminescence (OSL)-thermochronometry has recently been proposed as a tool capable of resolving cooling histories from the top 1–2 km of the Earth's crust. This is beyond the resolution of most low-temperature thermochronometric systems, and it offers a new opportunity to investigate the interactions between climate, tectonics and surface processes over Quaternary timescales. Here we present a multi-OSL-thermochronometer which exploits the different thermal stabilities of different temperature infra-red stimulated luminescence (IRSL) signals from K- and Na-rich K-feldspar extracts, utilising the established multi-elevated-temperature (MET) measurement protocol (Li and Li, 2011. Luminescence dating of K-feldspar from sediments: A protocol without anomalous fading correction. Quaternary Geochronology 6, 468–479). The theoretical aspects of multi-OSL-thermochronometry are discussed, prior to validation with an example from the eastern Himalayan syntaxis, one of the most rapidly exhuming settings on Earth. Our results show that multi-OSL-thermochronometry of feldspar is able to resolve rock cooling histories over timescales ≤0.2 Ma and provides much tighter constraint on late-stage cooling histories than single-system OSL-thermochronometry.