Exploring Rift Tectonovolcanism in Venus

One of the biggest open questions about Venus is the degree and extent of present-day volcanism [1]. Despite having a similar size and density to Earth, Venus underwent distinct geodynamic evolution. The planet hosts a wide diversity of tectonic and volcanic landforms, as revealed by NASA/Magellan global imagery (1990 – 1994) [2].

One prominent feature is the extensive, widespread rifts on Venus (e.g., [3]), covering about 8% of the planetary surface [4]. These are extensional structures [5], among the youngest geological features on the planet according to stratigraphic interpretation [6]. Evidence of recent rift volcanism has been suggested for Olapa Chasma [7 – 9] and Ganis Chasma [10 – 11]. However, the mechanisms of rift formation, age, and relationships with other structural features remain poorly understood, yet crucial for supporting modelling studies [12].

In this study, we analyse the tectonovolcanic activity of a few selected rifts on Venus using microwave emissivity as a proxy to constrain the weathering degree, relative age, and composition [11, 13 – 14], assuming the presence of ferroelectric minerals [13, 15 – 16]. We use Synthetic Aperture Radar (SAR), microwave emissivity, and elevation datasets collected from NASA/Magellan. Site selection, radar emissivity, and elevation extraction are performed in ArcGIS Pro to examine emissivity excursion with altitude. Complementary analyses based on stratigraphic relationships with structural features, such as lava flows, rift structures, and lineaments, provide relative chrono-stratigraphy and conceptual interpretation of tectonovolcanic activation processes. Thus, the objective is to provide a conceptual model for tectonovolcanic rift activation by combining microwave emissivity excursions, stratigraphic relationships, and stress patterns. These results are relevant to upcoming accepted and potential missions to Venus in the coming decade, which will yield extensive new data.

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Funding: DQ acknowledges this work to be supported by FCT - Fundação para a Ciência e Tecnologia, I.P. by project reference and DOI identifier 10.54499/2023.05220.BD. This work is supported by FCT, I.P./MCTES through national funds (PIDDAC): LA/P/0068/2020 - https://doi.org/10.54499/LA/P/0068/2020 , UID/50019/2025,  https://doi.org/10.54499/UID/PRR/50019/2025, UID/PRR2/50019/2025