Tectonics of Lakshmi Planum, Venus: Tests for Magellan

Abstract

The origin of Lakshmi Planum and its surrounding mountain belts remains an important unresolved element in the global tectonic framework of Venus. From the perspective of gravity signature and potential driving forces, the mantle upwelling model is the simplest and its principal failure, that it cannot produce radial shortening on the uplift periphery, may be resolved if the lithosphere is laterally heterogeneous. Our preferred model consists of a hot mantle plume rising beneath a pre‐existing block of tessera. The lithosphere is weakened at this hotter and presumably thicker crust, and the outward near‐surface flow is attenuated at the peripheral discontinuity in lithospheric strength. Crustal thickening and mountain belt formation occur there. We propose several criteria to test this “tessera‐plume” model together with its competitors at the higher resolution in both imaging and gravity afforded by the Magellan mission.