Developments in geophysics

Abstract

Recent claim by Jeffreys that thermal contraction is the only mechanism yielding a real reduction of the Earth remotely near sufficient for mountain-formation is demonstrably incorrect, since the phase-change hypothesis has been shown to lead inescapably to more than ten times the maximum amount possible on his theory. In any event, the absence of folded and thrusted systems on Mars proves that thermal contraction cannot be a relevant process, while the fact that the terrestrial planets began as ccol all-solid bodies completely rules out thermal contraction a priori as a possibility. Apart from the purely verbal claims associated with plate-tectonice, the phase-change theory remains the sole contender resulting in geologically adequate contraction.