Insight Into Venusian Ridge Belts With Maps, Models, and Earth Analogs

Abstract

Ridge belts are globally distributed mountain belts on Venus comprised of closely spaced shortening structures superimposed on longer wavelengths (1 km spacing over 30–400 km-wide belt), positive topography often surrounded by topographically smooth, intact crustal blocks. Although interpreted as large-scale shortening systems, we understand little about the causes of that shortening. On Earth, analogous mountain belts represent a range of crustal or tectonic block boundary collisions, and so the concentration of ridge belt structures could likewise be linked to crustal block collision at a reactivated suture or pre-existing crustal weakness. We can examine this hypothesis using structural maps, cross sections, and three-dimensional models of faults associated with ridge belts. We produced three detailed structural maps and 11 cross sections, which show that the ridge belts we selected represent two shortening styles-one with a single dominant fault, and one with two oppositely verging faults. These results may indicate that fresh or reactivated block collisions lead to ridge belt development.