Sulfates in the North Polar Region of Mars Detected by OMEGA/Mars Express

TLDR

The study focuses on the dark longitudinal dunes of Olympia Planitia in the northern circumpolar region of Mars. OMEGA imaging spectrometer mapped the northern circumpolar regions of Mars at a few‑kilometer resolution. A 60 × 200 km area at 240° E, 85° N shows spectral signatures of calcium‑rich sulfates, most likely gypsum, indicating that water alteration was key to forming the northern circumpolar minerals.

Abstract

The Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) imaging spectrometer observed the northern circumpolar regions of Mars at a resolution of a few kilometers. An extended region at 240 degrees E, 85 degrees N, with an area of 60 kilometers by 200 kilometers, exhibits absorptions at wavelengths of 1.45, 1.75, 1.94, 2.22, 2.26, and 2.48 micrometers. These signatures can be unambiguously attributed to calcium-rich sulfates, most likely gypsum. This region corresponds to the dark longitudinal dunes of Olympia Planitia. These observations reveal that water alteration played a major role in the formation of the constituting minerals of northern circumpolar terrains.