Lunar Ring Dikes from Orbiter I

Abstract

Orbiter photographs of the wall of a large circular formation on the moon show that the wall is a convex body resembling a flow of viscous lava. The slopes are less than the angle of repose of dry rock; hence an explanation in terms of mass wastage is hard to support. The viscosity is approximately 10¹³ centimeter-gram- second units, indicating an acid lava.