An unnamed fluvial valley system formed under different climates at Xanthe Terra, Mars

Analyzing an unnamed fluvial system (at 5.2N 301.4E) in Xanthe Terra on Mars for the first time, the following chronology could be reconstructed. The first period of the fluvial erosion of the area produced channels with higher drainage density than later events, but some resurfacing after this period erased these early, probably interconnected tributary systems and left behind only separate channel sections with eroded appearance. In the second period of fluvial erosion three deep and obvious channels were formed. In a third period, the main inlet to the terminal crater was eroded even more heavily. The last two episodes produced two different, characteristic cross sectional and longitudinal profiles: (1) narrow, shallow and nearly straight profiles, and (2) a wider, deeper and somewhat convex shaped profile. These two profile shapes resemble to other fluvial systems’ in the Xanthe Terra region. The existence of these two different types of channel morphology suggests the change in the erosional process could be at least regional and probably related to the change of fluvial erosion’s style on Mars forced by climatic changes.