|Impact craters are common on solid planetary bodies in our solar system and are one of the most important physical features from which the surface history of these planetary bodies can be deduced. Remote sensing is a crucial tool in planetary science and is essential in the detailed study of impact structures on planetary surfaces.
Oceans have been proposed to have existed on Mars during its history, the shorelines of which would coincide roughly with the crustal dichotomy that divides the smooth, northern lowlands with the cratered, southern highlands. Arabia Terra is a region on Mars that straddles the dichotomy and three proposed shorelines are located in the area. If Mars had a large ocean during its early history, Arabia Terra would be a
continental shelf area and hence an ideal location for the preservation of shallow-marine impact craters.
Shallow-marine impact craters on Earth exhibit characteristic morphological features. Due to the sub-marine formation and the influence of the water column, the morphologies of these craters are distinctly different from that of craters formed on land. Common attributes of marine impact craters include features of wet mass movement such as gravity slumps and debris flows; radial gullies flowing into the crater depression; resurge deposits and blocks of dislocated materials; a central peak terrace or peak ring terrace; crater rim collapse or breaching of the crater wall; and subdued topography. These features are visible from orbital imagery, and can thus be used to evaluate craters on Mars for possible marine origin. This study designed a simple quantification system that can be used to crudely judge and rank shallow-marine impact crater candidates based on the features observed in previously proposed shallow-marine impact crater candidates as well as features observed in terrestrial analogs. With the use of Mars Orbiter Laser Altimeter topographic data and Mars Orbiter Camera and Thermal Emission Imaging System imagery, the area bounded by 20º and 40º north as well as 20º west and 20º east is explored for evidence of shallow-marine impact craters. Based on the quantification system, 77 potential shallow-marine impact craters are found within Arabia Terra of which nine exemplary candidates were ranked with total scores of 70% or more.