Victoria Quadrangle - Structure

Structure

The ridges associated with the intermediate plains unit are best interpreted as tectonic in origin because they extend into adjacent exposures of intercrater plains material and, more significantly, because they transect ejecta, rims, and floors of craters. The ridges range in length from about 50 km to many hundreds of kilometers, are sinuous to lobate in plan, and generally trend about north-south. Most are asymmetric, with one slope steeper than the other, and at places they can be more logically referred to as rounded scarps. Commonly, an individual ridge changes along trend from symmetric ridge to asymmetric ridge to rounded scarp. Strom and others interpreted most of these features to be surface expressions of thrust faults, and we can find no evidence within the Victoria quadrangle not already considered in their discussion.

Because of their globally systematic orientations, these ridges and scarps have been associated with stresses developed by tidal despinning of Mercury. However, most trend approximately north-south and thus do not fit the pattern expected in the midlatitude belt, unless stresses from overall contraction were superposed on the stresses due to despinning.