Wind-snow interactions at the Ojos del Salado region as a potential Mars analogue site in the Altiplano - Atacama desert region

Abstract

We describe the general characteristics and interactions happening at a unique, potential new Mars analogue site, located in the Altiplano and Atacama Desert region: the Ojos del Salado inactive volcano. The interaction between rare snowing events and strong winds transported large masses of porous volcanic grains there could produce decimeter - meter thick buried snow masses fast, shielded against sublimation for extended periods (years). Subsurface temperature logging suggests that water ice melting is rare and surface modification is dominated by desiccation of the cryosphere and wind activity – just like on Mars. The first analysis of aeolian transported grains in the area points to immature material sized between coarse sand and coarse silt, and indicates the possibility of larger snow occurrence in winter when the site is inaccessible – however further observations are necessary The site contains decameter scale megaripples, which are unusual for Earth and also support the understanding of resemble features on Mars. The shallow subsurface analysis with Mars relevance is supported here by drilled cores of evaporitic sediments presented carbonate, aragonite, anhydrite, talc and clay minerals in the shallow subsurface with Mars relevance. Though the region is generally felsic in composition, basalts can be found at a hillside near Laguna Verde where the effect of extreme conditions (including the strong UV radiation) on rock weathering could be analysed. The temperature, dryness, wind exposure, decreased atmospheric pressure and elevated UV radiation together make Ojos del Salado a unique Mars analogue site, and it is accessible up to 5200 m altitude by regular pick-up trucks via a 5–6 h driving from the Copiapo airport.