The impact of tectonic-style on marine transgression and evolution

Abstract

Plate tectonics drives variation in sea-level, over intervals of approximately107–108years. These variations may have significant effects on the pace of (biological) evolution through the elimination of terrestrial niches and the expansion of shallow-water marine niches. However, within the solar system, only the Earth experiences this kind of tectonism. Venus displays regional tectonism, characterized by rising diapirs within the plastic mantle. Impinging on the lithosphere, these plumes produce a range of structures of varying dimensions; the uplift of which would raise sea-level, were Venus to have oceans. Using Magellan observations of Venus, we model the impact of regional tectonism on sea-level for given areas of Venusian ocean, then compare the effect with terrestrial tectonic processes for similar oceanic area. We show that despite variation in the geographical extent of Venusian-style tectonic processes, the styles of regional tectonism on Venus can produce the same order of magnitude changes in sea-level, for a given area of ocean, as plate tectonics. Consequently, we examine some of the impacts of marine transgression on habitability and the evolution of life.