Shallow ground temperature measurements on the highest volcano of the Earth, the Mt. Ojos del Salado, Arid Andes, Chile

The Mt. Ojos del Salado (6893 m a.s.l.) is situated within the Andean Arid Diagonal, on the Chilean-Argentinean border. Due to the extremely arid climate, surface ice is not widespread on the Mt. Ojos del Salado and at similar high altitude massifs in the region, though ice-bearing permafrost might be present. However, the thermal regime of the ground is relatively unknown in the region, especially outside of rock glaciers at high elevations north of 30°S. To study ground thermal regimes, in-situ shallow ground temperature and snow coverage from satellite imagery have been surveyed for four years (2012-2016) at six sites between the elevations of 4200-6893 m a.s.l. on the Mt. Ojos del Salado (27°07ʹS, 68°32ʹW). According to the ground temperature and snow coverage data at the six monitoring sites, the presence of permafrost is unlikely below 4550 m a.s.l. but likely above 5250 m a.s.l. on the Mt. Ojos del Salado. It was also observed that the active layer becomes extremely thin around 6750 m a.s.l.