Supplementary materials for PhD thesis - "Venus: Petrological-Geophysical Modelling Of The Crust To Understand Tesserae Composition"
<p dir="ltr">This comprises the model files produced and MATLAB code used over the course of the thesis "Venus: Petrological-Geophysical Modelling Of The Crust To Understand Tesserae Composition"</p><p dir="ltr">Abstract:</p><p dir="ltr">The highly deformed and elevated terrain of Venus known as tesserae show similarities to continental crust on Earth. However, the history of their formation and composition remain a highly debated scientific question. Constraining the formation of tesserae would provide insights into the conditions of Venus early in its history, including the water budget of the planet and past habitability.</p><p dir="ltr">In this thesis, I use petrological and isostatic models to evaluate the stability of tesserae with a set of potential rock compositions, from silica-poor to silica-rich, under a range of thermal gradients and water contents. I perform phase equilibria modelling using the Perple_X Gibbs free energy minimisation software under anhydrous and water-bearing conditions. These were used to calculate the maximum crustal thickness which could be supported by the compositions and whether water may still be contained within the crust of present-day Venus.</p><p dir="ltr">I then performed isostasy calculations using the maximum crustal thickness and average crustal density from the phase equilibria models to find the elevations which can be supported by the modelled compositions under a range of conditions. These elevations were compared to those of observed tesserae on Venus to discern whether felsic material is required to support any tesserae on Venus. I found that under anhydrous conditions, tesserae above 3.2 km must be composed of silica-rich rock types and experiencing a thermal gradient of 10 °C/km or below in order to be stable. Additionally, I show that in the present day the tesserae are unlikely to contain water as it limits the elevations of tesserae to a maximum of 3.1 km.</p><p dir="ltr">My findings show that, isostatically, silica-rich material must be present on Venus. This provides support for the occurrence of a water-rich period during the early history of Venus, with potentially habitable conditions and surface water.</p>
