Evidence of late Mars geological activity on the floor of the Gusev and Jezero craters. Landing sites of NASA's Mars exploration missions.

Abstract

<p>The Gusev crater, landing site of the MER-A mission, and the Jezero crater, site of the Mars2020 mission, currently located near the Martian equator. They may have been two fluvial-lacustrine systems from the planet's wet past, Nevertheless, cortical fractures, ridges and basaltic flows are present in the bottom of both craters. These features are well preserved and not affected by large craters, which seems to indicate that could be young and contemporary forms. Mapping of both Gusev Crater and Jezero Crater has been carried out by remote sensing onboard the Mars Reconnaissance Orbiter (MRO), of particular interest for Gusev Crater is the Context Camera (CTX)-based high-detail mapping, which improves the resolution of previous studies, and the High-Resolution Imaging Experiment (HiRISE). These are complemented by data from the Thermal Emission Imaging System (THEMIS) and Mars Orbiter Laser Altimeter (MOLA), the Mars Global Surveyor (MGS) mission. CTX and HiRISE are visible images that provide information about the surface features of morphological units in detail. The MOLA data have made it possible to determine the stratigraphic position of the mapped units and to obtain information on the slopes and elevations of the units, as well as to estimate the fill of both craters. The combination and analysis of these data show possible evidence of geological activity on the surface of these craters in more recent periods of Mars' past (millions of years). Crater counts (crater frequency) have been used to determine a possible age for the ridges described in crater Gusev. These indications may be associated with volcanic activity and horizontal “strike-slip” movements affecting the ridges observed in Gusev crater, as well as crustal fracture and the presence of basaltic plains in Jezero crater.</p>