In analysing the topographical maps of Venus, which were made in the 1990s with radar information from the American Magellan mission, enabled scientists to identify up to 10 000 volcanoes on Venus. Some of the lava flows from these volcanoes stretch over hundreds of kilometres, covering areas as large as Germany.
The picture shows a radar picture from the Magellan probe of the Mylitta Fluctus region, in which solidified lava flows can be seen. Their structure resembles that of basalt lava flows on Earth. Basalt an igneous rock which is relatively low in silicon, is fluid as lava at temperatures around 1000°C, and occurs regularly on the Earth – for example in the islands of Hawaii, or on the sea bed, which constitutes two-thirds of the Earth’s crust.
Mylitta Fluctus is in an area in the southern hemisphere of Venus that has been studied intensively in the last two years with the VIRTIS (Visible and Infrared Thermal Imaging) spectrometer on board the ESA space probe Venus Express. Differences with the previously-predicted temperatures of the extinct volcanoes there could now be ascertained. Mylitta Fluctus also has high values for heat radiation. The scientists attribute the differences in temperature to differences in the composition of the solidified lava, which may indicate that the volcanoes were created at different times.