Element composition of Venus rocks - Preliminary results from Venera 13 and Venera 14

The element composition of rocks on Venus was determined for the first time when samples were extracted by special drills at the Venera 13 and Venera 14 landing sites and analyzed by X-ray fluorescence spectroscopy. The samples are representative of the two most typical forms of Venus terrain: rolling upland (Venera 13) and flat lowland (Venera 14). At Venera 13 the rock composition resembles potassium alkalic basalts; at Venera 14, the tholeiitic basalts in the terrestrical crust. Comparison of the typical Venus rock composition with that of rocks in analogous structural-morphological provinces on the earth suggests certain differences in the formation of the surface and crust of the two planets.