A heterogeneous lithosphere on Venus

TL;DR

Venus exhibits a complex, heterogeneous lithosphere with significant regional variations in crustal thickness and volcanic activity, challenging existing models of its internal thermal evolution.

Contribution

This study reveals the first detailed regional differences in Venus's volcanic plains, indicating a heterogeneous lithosphere and complex geodynamical processes.

Findings

Three distinct volcanic provinces with different properties identified.

Northern plains have thinner lithosphere and more volcanoes than southern plains.

Global variations suggest complex mantle convection and planetary evolution models.

Abstract

Venus is 95% the size of Earth and probably has a similar composition and internal energy, but the geodynamical mechanism governing its internal thermal evolution remains controversial. Much of the planet surface (77%) is covered by volcanic plains, characterized by basaltic flood lavas, some of which emanate from volcanoes whereas others have no identifiable sources. Here we show that the volcanic plains contain three provinces with statistically different properties. Apart from the plains around the Beta-Atla-Themis region characterized by a thick crust with a wide range of effective elastic lithospheric thickness (Te), the remaining volcanic plains (61% of the surface) display a dichotomous nature, with the northern plains showing a thinner lithosphere and twice the number of volcanoes per unit area compared to the southern plains. These global-scale differences imply a complex geodynamical regime, with large lateral variations in mechanical properties and/or geodynamical processes, which must be addressed by competing models of mantle convection and planetary evolution.