Proof of Volcano–Tectonic Origin of Mare Terrain on the Moon

Abstract

ONE of the Apollo 8 series of photographs, covering the Cauchy Fault, Crater and Scarp area of the lunar surface (Fig. 1), shows a pattern of faulting that is virtually identical with the uppermost Pleistocene–Holocene “grid” or “touche-de-piano” (keyboard) faulting in the Baringo sector of the Rift Valley in Kenya (Fig. 2). (Gregory has compared this faulting with the platforms at Clapham Junction station¹!) It is not just the step effect that is similar—the persistence of a master trace with branching traces fading out, the passage into en echelon conformation at one end and into monoclinal flexuring near the other, the crescentic steps with the convex curve towards the downthrow side, the cross-over effects, the close-spacing of the faults forming narrow ledges—all these are shared characteristics with the rift valley fault structures on the south-eastern slopes of Silali Volcano². The Cauchy Scarp is actually the more perfect fault zone structure of the two, and it clearly involves gravity faulting on very steep fault surfaces, just like the rift valley faulting (the surfaces are close to vertical in most cases).