Geomorphology of the southwest Sinus Sabaeus region: evidence for an ancient hydrological cycle on Mars

Abstract

We have produced a 1:650,000 scale geomorphological map of the southwest Sinus Sabaeus, a region of Mars approximately centered at 25.0°S and 6.5°E and located in the topographic transition between Arabia Terra and Noachis Terra, in the Martian highlands. This heavily cratered region, subjected to extensive surface erosion, shows a complex valley network system known as Marikh Vallis. In this work, we study the history and role of water in and around Marikh Vallis, focusing on the modification and evolution of this area during the earliest Martian times, the Noachian period. The map described in this paper was produced through the analysis of a combination of available imagery data, topography, and thermal inertia, which together allow defining different geomorphological units in this area. This new map provides a basis for identifying the ancient presence of water in the region, both in the liquid state and in the ice phase.

High Resolution Map of Water in the Martian Regolith Observed by FREND Neutron Telescope Onboard ExoMars TGO

“…LWRR‐10 is located in Marikh Vallis, part of Noachis Terra (Figures 2a, 6 and 7), and lays very close to the border with Arabia Terra, a vast “wet land” around the Martian equator studied in numerous previous studies (see e.g., Andrews‐Hanna et al., 2010; Zabrusky et al., 2012). In Marikh Vallis observations have shown the presence of a valley network, which is another sign of extended hydration in the past, for example, (Orofino et al., 2018; Robas et al., 2021). LWRR‐17 is also associated with Arabia Terra (Figures 2a, 6 and 7), located practically in the center of it, just 10° northward from the equator and overlapping Henry crater, where observations have shown the presence of layered deposits that may have preserved water which we see now (Day & Catling, 2020).…”