Volcano dynamics vs tectonics on Pavonis Mons (Mars)

Volcanic activity is widespread within the inner Solar system and in rocky planets. In this work we study the interplay between magmatic activity and tectonic processes on Pavonis Mons in the Tharsis volcanic province of Mars using structural mapping and analytical modelling. Here we explore whether volcano dynamics or tectonic processes controlled deformations at Pavonis Mons by analysing i) the variation of graben azimuth distribution from its base to the summit, ii) the spatial clustering of grabens and pit chains in the volcano and iii) the structures on the volcano summit and its possible source mechanism. We find that the azimuthal distribution of grabens shows two main patterns: concentric grabens occur on the volcano summit and linear grabens at its base. We interpret the linear grabens at the base of the volcano as evidence of active rifting followed by a phase of volcano growth and magma resurfacing when concentric grabens formed due to the volcano dynamics. We also inverted the topography with dykes and faults models and a combination of both to test whether grabens at the surface are the expression of intrusions at depth or are purely extensional features. We found that the models including dykes predict uplift of the flank which is not observed in the data, indicating that either the dykes in Pavonis were thin or that significant flank erosion occurred.