NATURE AND ORIGIN OF TSIOLKOVSKY CRATER LUNAR FARSIDE

The principal geological units which make up the Tsiolkovsky structure are defined and described, and their age relations and origin established wherever possible. From this evidence it is concluded that an impact origin is most likely for the main structure, but that later volcanic outbursts occurred. The most compelling evidence in favour of impact is the presence of a ring of high crater density at about one crater diameter from the rim; most craters in this ring are considered to be secondary impact craters. The strong circularity of the crater does not favour a caldera origin. Some features of Tsiolkovsky are compared with other large lunar craters. © 1969.