Arabia Terra, Mars: Tectonic and palaeoclimatic evolution of a remarkable sector of Martian lithosphere

Abstract

A regional geologic study of Arabia Terra, a densely cratered area of Mars northern hemisphere, has revealed the individuality of this province. This is best expressed by an equatorial belt with a crater age distinctly younger as compared to the northern part of Arabia Terra and to Noachis Terra to the south. We interpret this as an incipient back-arc system provoked by the subduction of Mars lowlands under Arabia Terra during Noachian times. The regional fracture patterns are also best explained in this manner, making it unnecessary to appeal to a rotational instability of the planet, which is not supported by the palaeoclimatic indicators in the area. This model could be the first regional-scale confirmation of Sleep's (1994) hypothesis of a limited plate consumption as an explanation of the martian dichotomy.