Ovda Fluctus, Venus: Silica-rich Composition Called into Question

Top: Magellan Radar mosaic of Venus; the arrow shows the Ovda Regio plateau. Bottom: The Ovda Fluctus lava flow which is found on top of Ovda Regio. The dark line shows its margin. Image credit: NASA

A recently released paper by Wroblewski, et al. has taken a fresh look at Ovda Fluctus on Venus, which has been interpreted as a silica-rich lava flow. This lava flow and two others like it are dubbed โ€œfestoonโ€ flows due to the presence of pressure ridges on the surface of the flow. These flows are of particular interest because they are unusually thick, which led various groups to interpret them to be similar to terrestrial rhyolite or dacite. If this is the case, then Venus must have had large amounts of water in its history. However, Wroblewski, et al. have determined through the use of Magellan radar data and fractal dimensions, in conjunction with the geologic setting and morphology of the flow, that an evolved magma source is not required to explain the observed physical properties of Ovda Fluctus. Furthermore, a basaltic lava is actually a better match for their observations. While the authors are clear that this work does not constrain the overall composition of Ovda Fluctus or the underlying tesserae, the rheology implied by their observations does call into question the geologic evidence for evolved magmas on Venus. READ MORE

Read press release here.