Tektites as a guide to the structure of the moon

Abstract

Experience shows that morphological data by itself does not give decisive answers to the question of the mode of formation of the surface of the moon. Some chemical information is needed. If tektites are from the moon, they furnish that information. Tektites are the result of impact on some surface, because they contain nickel-iron spherules and coesite. The surface was probably not the surface of the earth because the same tektites that contain coesite consist largely of glass, and the glassmaking process is inconsistent with the survival of coesite. Hence the material was glass before the impact, but highly siliceous glasses with low water content of this kind are not found on the earth. Tektites do not come from interplanetary space because their distribution over the earth is explicable only if we suppose them to be fragments of orbiting bodies. They are, therefore, probably lunar. Accepting the Muong Nong tektites as essentially fragments of the lunar crust, we find a certain resemblance to terrestrial ash-flow tuffs. This resemblance is borne out by their dryness and by the following consideration: Tektites have been differentiated relatively late in the history of the solar system. If they are lunar, we would expect that they came from the maria. The maria are flat; if composed of acid rock we would expect that they were ash flows. The Ranger photographs support this view because they contain evidence of differential compaction. They also contain evidence of recent acid volcanism. Comparison of the Ranger photographs with the Valley of Ten Thousand Smokes supports the analysis which we have made here.