Which geomorphic processes can be informed by luminescence measurements?

Abstract

Luminescence signals from quartz and feldspar contain a wealth of information about exposure to heat and sunlight. While many studies have focused on quantifying individual processes such as grain transport and burial, cooling during exhumation, or bleaching of freshly exposed rock surfaces, not much work has yet been done to illustrate how these effects might interact. For example, how might a geomorphologist interpret the luminescence signals within a riverine cobble or within a recent rockfall from an uplifting terrain? This study attempts to address this issue by first presenting a simple kinetic expression for OSL signal accumulation in response to background radiation, and OSL loss by exposure to heat or to direct or attenuated sunlight. This model is then used to simulate three example sample histories. Simulation results 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 with luminescence signals are presented in comparison to those of various geomorphic processes. Finally, simulation results illustrate the benefit of using signals of different stability to better understand a sample's recent geologic history.