Rifting Venus: Insights From Numerical Modeling

Journal of Geophysical Research Planets, vol. 128

Abstract

Abstract Venus is a terrestrial planet with dimensions similar to the Earth, but a vastly different geodynamic evolution, with recent studies debating the occurrence and extent of tectonic‐like processes happening on the planet. The precious direct data that we have for Venus is very little, and there are only few numerical modeling studies concerning lithospheric‐scale processes. However, the use of numerical models has proven crucial for our understanding of large‐scale geodynamic processes of the Earth. Therefore, here we adapt 2D thermomechanical numerical models of rifting on Earth to Venus to study how the observed rifting structures on the Venusian surface could have been formed. More specifically, we aim to investigate how rifting evolves under the Venusian surface conditions and the proposed lithospheric structure. Our results show that a strong crustal rheology such as diabase is needed to localize strain and to develop a rift under the high surface temperature and pressure of Venus. The evolution of the rift formation is predominantly controlled by the crustal thickness, with a 25 km‐thick diabase crust required to produce mantle upwelling and melting. The surface topography produced by our models fits well with the topography profiles of the Ganis and Devana Chasmata for different crustal thicknesses. We therefore speculate that the difference in these rift features on Venus could be due to different crustal thicknesses. Based on the estimated heat flux of Venus, our models indicate that a crust with a global average lower than 35 km is the most likely crustal thickness on Venus.

Authors 6

1. Alessandro Regorda corresponding

   University of Milan

   Affiliation as printed

   Department of Earth Sciences Università degli Studi di Milano Milan Italy

2. Cédric Thieulot

   Utrecht University

   Affiliation as printed

   Department of Earth Sciences Utrecht University Utrecht The Netherlands

   Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands

3. Iris van Zelst

   Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

   Affiliation as printed

   Institute of Planetary Research German Aerospace Center (DLR) Berlin Germany

   Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany

4. Zoltán Erdös Aachen Tectonics and Geodynamics

   GFZ Helmholtz Centre for Geosciences · RWTH Aachen University

   Affiliation as printed

   Tectonics and Geodynamics RWTH Aachen University Aachen Germany

   The Helmholtz Centre Potsdam ‐ GFZ German Research Centre for Geosciences Potsdam Germany

   Tectonics and Geodynamics, RWTH Aachen University, Aachen, Germany

   The Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences, Potsdam, Germany

5. Julia S. Maia

   Centre National de la Recherche Scientifique · Université Côte d'Azur · Lagrange Laboratory · Observatoire de la Côte d’Azur

   Affiliation as printed

   Observatoire de la Côte d’Azur Laboratoire Lagrange CNRS Université Côte d’Azur Nice France

6. Susanne Buiter Aachen Tectonics and Geodynamics

   GFZ Helmholtz Centre for Geosciences · RWTH Aachen University

   Affiliation as printed

   Tectonics and Geodynamics RWTH Aachen University Aachen Germany

   The Helmholtz Centre Potsdam ‐ GFZ German Research Centre for Geosciences Potsdam Germany

   Tectonics and Geodynamics, RWTH Aachen University, Aachen, Germany

   The Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences, Potsdam, Germany