Age and Origin of the Crustal Dichotomy in Eastern Mars
نویسنده
چکیده
The topography associated with the fundamental crustal dichotomy in much of eastern Mars can be largely ascribed to a single event: the very large impact which produced the Utopia Basin. Subsequent internal and surficial processes have been unable to remove the topographic signature of this basin. In particular, endogenic processes appear to have been ineffective in contributing to the basic dichotomy in eastern Mars since the basin formed. Also, if earlier endogenic processes occurred, their signatures were obliterated by the impact. Early Noachian buried impact basins superimposed on the Utopia Basin, and the superposition of the Early Noachian Isidis Basin on the dichotomy boundary on the southern side of Utopia, constrain the Utopia impact to be very Early Noachian in age. The Utopia basin may be the oldest preserved large scale structure on Mars. The crustal dichotomy in eastern Mars dates from the earliest epoch of martian history.
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