Arabia Terra, Mars: tectonic and palaeoclimatic evolution of a remarkable sector of martian lithosphere

Abstract

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.