Progress towards robotic in-situ dating of martian sediments using optically stimulated luminescence

Recent exploratory efforts to reveal the evolution and the climatic history of Mars have shown that the planet is still active. The surface of Mars has been, and continues to be, shaped by fluvial, eolian and glacial processes. The timeframe of these events is, however, poorly established. We describe efforts and challenges to adapt optically stimulated luminescence (OSL) dating for robotic in-situ dating of martian sediments. Mineral mixtures were devised as simulants of martian regolith. The single-aliquot regeneration (SAR) procedure was modified to enable the determination of the equivalent dose for polymineral samples. Low-temperature measurements and simulations indicate that known doses delivered at low temperatures can be effectively estimated as long as the stimulation temperature is greater than the highest temperature experienced during the initial irradiation. Bleaching experiments with a solar simulator suggest efficient zeroing of the OSL signal for solar-exposed sediments on Mars. Irradiations with proton and heavy-charged particles show a lower efficiency in luminescence production than that found for beta and gamma radiation. r 2007 Elsevier Ltd. All rights reserved.