¹Sam Uthup, ¹J. Gregory Shellnutt
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2026.116985]

¹Department of Earth Science, National Taiwan Normal University, 88 Tingzhou Road Section 4, Taipei 11677, Taiwan
Copyright Elsevier

Venus is a telluric planet with similar size, composition, and mass to that of the Earth. The Venusian crust is mainly divided into lowland (~80%) and highland regions (~10%) based on their surface elevation. The lowland regions are characterized by featureless lava plains, whereas the highlands consist of crustal plateaux, tesserae terrane, and volcanic troughs. The presence of evolved silicic igneous rocks in the highland regions of the Venus has been debated. In this study, phase equilibria modelling using THERMOCALC and the basaltic compositions obtained from the Venera 14 and Vega 2 lander missions are employed to estimate partial melt compositions in both hydrous and anhydrous conditions. Hydrous partial melting of the Venera 14 composition generated tonalitic-trondhjemite-granodiorite- (TTG) melts at shallow crustal depths with 5% partial melting. The Vega 2 composition could also generate TTG like melts in hydrous conditions, but at a slightly higher-pressure (~5 kbar). However, anhydrous partial melting modelling results were unable to generate a TTG-like melts. The results of THERMOCALC modelling indicate that TTG-like melts can be generated in the crust from the basaltic compositions of Venera 14 and Vega 2 by hydrous partial melting. The implication is that the highland regions of Venus may be an ideal location to search for silicic rocks that are typical of terrestrial Archean crust.