Geology of the Venera and Vega landing-site regions

Using Magellan radar images of the Venera and Vega landing-site regions, we carried out a photogeologic analysis and mapping of these regions, the soil composition of which was earlier analyzed by the spacecraft of these series. All these landing-site regions are shown to possess a similar set of geologic situations, which are typical of the planet as a whole, and a similar sequence of geologic evolution. Judging by the results of mapping, a geochemically advanced material analyzed at the Venera-8 landing site appears to be a complex of shield plains (Psh). Tholeiitic compositions obtained by Venera-9/10 and Vega-1/2 probably represent the unit of plains with wrinkle ridges (Pwr), which is most common on Venus. The material of tholeiitic composition analyzed by Venera-14 is likely to be the unit of relatively young lobate plains (PI).