Structures of Coronae on Venus: Results of Topographic and Geologic Analysis

Abstract

From the analysis of the topography and geology of coronae on Venus, the most common topographic profiles of coronae were obtained, their relative age was estimated by the characteristic annulus type and the relation with the surrounding volcano−tectonic units, and the corona evolution stages consistent with numerical modeling results for the evolution of mantle diapirs on Venus were determined. It has been found that most coronae is the manifestation of a late regressive stage of the evolution of mantle diapirs. These coronae are spatially associated with groove belts and characterize late episodes of the tectonic resurfacing regime. According to our results, the number of coronae that may appear at the early and late phases of the regressive stage is almost the same. This allows us to suppose that the parent corona-forming diapirs were mostly formed at the end of the tectonic regime, but this activity had terminated before extensive lava plains (shield and regional plains) were formed during the volcanic regime. A minor portion of the entire corona population (18%) represents the initial, progressive, stage in the evolution of diapirs, which is characterized by growing a dome-shaped structure above a diapir.