Thrust faults and the global contraction of Mercury

Abstract

Lobate scarps on Mercury are the surface expression of thrust faults and are generally thought to be the result of global contraction. Our analysis indicates that these thrust faults are not uniformly distributed and exhibit non-random patterns on the imaged hemisphere. The greatest area normalized cumulative length of the faults occurs in the southern hemisphere, below 50°S. The thrust faults in this region dip to the north, indicating a broad zone where the crust has been displaced to the south. Widespread thrust faulting may not have initiated before the emplacement of Calorian smooth plains, well after the emplacement of pre-Tolstojan intercrater plains. Our observations suggest that regional-scale tectonic stresses on Mercury dominated over stresses resulting from global contraction. Copyright 2004 by the American Geophysical Union.