Albert F. Noonan

Meteoritic, lunar and lonar impact chondrules

Impact-generated silicate spherules from the Lonar Crater, India and from all Apollo sites are analogous to meteoritic chondrules (and some microtektites). Thus, the impact origin of chondrules, first proposed by Urey (1952) is a mechanism strongly supported by physical evidence from both the Moon and the Earth. Chondrites appear to be essentially impact breccias similar to lunar and Lonar microbreccias. The implications of this with regard to size and composition of the meteorite parent bodies are reviewed as well as the possible variations of element fractionation by volatilization-condensation.