Recent faulting at the Claritas Rupes scarp on Mars

Abstract

Endogenic processes have greatly affected the Martian surface, especially concentrating at several volcano-tectonic centers. The formation of Tharsis, a vast volcanic bulge, significantly influenced the western hemisphere of Mars. The associated loading stresses caused the formation of various sets of tectonic structures that might have remained active until today. However, surface evidence for very recent endogenic processes in Tharsis is sparse. Here, using the Context Camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) images, we report the presence of fresh-appearing systems of local-scale scarps mostly developed at the southern edge of Tharsis, specifically at Claritas Rupes scarp. These scarps are spatially associated with depression centers situated at the base of Claritas Rupes, inside the Thaumasia Graben which is partially filled by volcanic deposits. The relationships between the studied scarps and present-day surficial processes and its deposits such as rockfalls indicate a young age of the scarps' development, namely, in the range of <1 Ma. The pristine topography (sharp and thin ridges), spatial distribution (association with depression centers), and regional geological context of Claritas Fossae lead us to interpret these scarps as surficial expressions of tectonic activity attributed to normal faulting. This could be related to Deep-seated Gravitational Slope Deformations (DGSDs) released by seismic activity related to ongoing subsidence of depression centers and/or reactivation of the listric normal Claritas Rupes fault. These observations imply that this region experienced long-lasting and multiple volcano-tectonic events and the formation of the youngest deformations could represent neotectonic activity, which has been active until recently, and possibly might be still ongoing.