Age and evolution of the lower NW flank of the Hecates Tholus volcano, Mars, based on crater size-frequency distribution on CTX images

Our results are in general in agreement with previous works, and establish that the age of the origin of the Hecates Tholus volcano could be at least 3.8 Ga, with possible volcanic eruptions occurring until at least 335 Ma. Glacial events were also dated at 90 Ma, 30 Ma, 16 Ma, and 6 Ma, although it is possible to recognize ages which could also be related to the recent ice ages of Mars, between 2 and 0.4 Ma. Our results allowed us to determine that glacial processes could have been active as far back as 1.4 Ga, with possible events at intermediate ages. We deduced from the resulting ages and our observations on CTX images and the available geomorphological map of the area, that glacial-related processes played an important role in sculpting this flank of the volcano, and the possible level of the glacial sheet at the edge of the main depression of this flank was also deduced, with altitudes ranging between −2035 m and −2490 m, in agreement with the presence of smooth outcrops and roche moutonnées in the area. Finally, a possible evolution of this region of the Hecates Tholus volcano is proposed and discussed, establishing the sequence of the most important geological events which occurred in the area and their possible timings.