Reading Quaternary landscapes with luminescence signals from detrital clasts and sand grains

Abstract:

Luminescence signals from quartz and feldspar can record grain transport and burial timescales, cooling during rapid exhumation, solar bleaching of freshly exposed rock surfaces, and even provenance. This study highlights the flexibility and sensitivity of this geochronometer by using a simple kinetic expression for luminescence signal accumulation in response to background radiation, and luminescence loss by exposure to heat or to direct or attenuated sunlight. I simulate several sample histories to demonstrate how much information can be embedded within one sample's luminescence signal and how disparate geomorphic histories can produce strikingly similar signals. The temperatures and timescales which can be examined using luminescence signals are presented in comparison to those of various geomorphic processes including lava flows, shear heating in fault gouge, and wildfire exposure. Finally, simulation results illustrate the benefit of using signals of different stability to better understand a sample's recent geologic history.