Megan's Blog

In the news this month... volcanoes on Venus

Closer to home, the planet Venus shows large amounts of evidence of volcanic activity. Despite being shrouded under a thick layer of cloud, spacecraft have been able to map the surface of our nearest neighbour using radar, leading to the realisation that much of the planet's surface is comparatively young, suggesting that at some point in the recent past the planet underwent a complete resurfacing. However the question remains whether Venus is currently a geologically active planet.

Most of the planet's surface is known to be covered by features caused by volcanic activity: shield volcanoes, coronae, pancake domes and other features caused by lava flows or crustal uplifts. The relative lack of craters, compared to known ancient surfaces like the Lunar and Martian highlands, implies that the surface is comparatively young. While the thick atmosphere of Venus prevents observers from seeing directly signs of current volcanic activity, a team using data from the Visible and Infrared Thermal Imaging Spectrometer on board the European Space Agency's Venus Express orbiter have discovered evidence of recent resurfacing.

The team used data from the VIRTIS instrument to examine closely several known hot spots on Venus. These hot spots are analogous to their terrestrial counterparts such as the Hawaiian chain of islands in that they have distinctive rises compared to the surrounding terrain, major volcanic centres and gravitational anomalies, suggestive of active plumes of material flowing up through the planet's mantle.

By studying the thermal emissivity of these regions, the researchers have identified compositional differences in lava flows at these hot spots compared to the surrounding surfaces, which they interpret as being due to a lack of surface weathering. Since weathering is a gradual process which occurs over long time scales, this all implies that the features are younger than 2.5 million years, and possibly much younger, showing that Venus has been actively resurfacing, at least partially, in the recent past. The results were published in Science Express on April 8th.

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This blog post is a news story from the Jodcast, aired in the May 2010 edition.

Smrekar, S., Stofan, E., Mueller, N., Treiman, A., Elkins-Tanton, L., Helbert, J., Piccioni, G., & Drossart, P. (2010). Recent Hotspot Volcanism on Venus from VIRTIS Emissivity Data Science, 328 (5978), 605-608 DOI: 10.1126/science.1186785