Influence of bulk composition and lava flows on the long-term evolution of Venus

Venus’ mass and radius are similar to those of Earth, yet its internal structure, chemical composition, and overral evolution and dynamics remain poorly constrained. A striking difference is Venus’ exceptionally long lava flows, for example observed by NASA’s Magellan mission, which may play a critical role in shaping its evolution and surface tectonics. Small deviations from Earth-like properties could explain the different geological and atmospheric histories of the two planets. We investigate the influence of possible bulk compositions and internal structures on Venus’ thermal and compositional evolution. Using ten models from Shah et al. (2022) that range from a small to big and S-free to S-rich core, we perform mantle convection simulations with the code StagYY (Tackley, 2008). Different tectonic scenarios are explored, including stagnant lid, episodic lid, and plutonic-squishy lid regimes. Variations in core size and composition significantly affect mantle melting, heat flow, lithospheric temperature, and observables such as…