Uranium, Thorium, and Potassium in the Venusian Rocks at the Landing Sites of Vega 1 and 2

Concentrations of natural radioactive elements in Venusian rocks at the landing sites of Vega 1 and Vega 2 were determined by gamma ray spectrometers on the landers as follows: Vega 1‐K = (0.45 ± 0.22)%, U = (0.64 ± 0.47) × 10 −4 %, Th = (1.5 ± 1.2) × 10 −4 %; Vega 2‐K = (0.40 ± 0.20)%, U = (0.68 ± 0.39) × 10 −4 %, Th = (2.0 ± 1.0) × 10 −4 %. The abundances of natural radioactive elements in the investigated rocks are similar to that of basic rocks (tholeiitic basalts and gabbros) of the earth's crust. The same conclusion about the type of the rocks at the landing site of Vega 2 was made from the XRF experiment.