Development of methods for in situ dating of martian sediments

Abstract

We examine the optically stimulated luminescence (OSL) characteristics of two potential martian soil simulants for purposes of determining the most effective procedures for OSL dating of surface sediments on Mars. The two simulants (OSU-Mars-1 and OSU-Mars-2) are composed of plagioclase, clinopyroxene, and potassium-rich glass, in various proportions. The compositions are based on thermal emission data from the Mars Global Surveyor spacecraft. Using these simulants we devise an OSL single-aliquot regeneration (SAR) technique using infra-red (IR) stimulated luminescence, and post-IR blue stimulated luminescence. We also determine the outline procedures necessary to conduct a successful SAR procedure for samples irradiated at low martian ambient temperatures by using a low temperature cryostat and performing irradiations and OSL stimulation at a variety of temperatures. Finally, we calculate the martian solar spectrum, taking into account the atmosphere of Mars and scattering by atmospheric dust. Using this we examine the efficiency of the solar spectrum at bleaching (“zeroing”) the OSL signal from the martian soil simulants.