THE ORIGIN OF DIAMONDS AND THE DEEP GAS HYPOTHESIS

Abstract

Recent work by Thomas Gold and Steven Soter at Cornell University on the nature and quantity of gases deep within the earth provide new ideas on that most puzzling of gemmological problems: the origin of diamonds. Diamonds can be interpreted as having been formed by the movement of a dense gas, one of whose constituents was abiogenic methane, through pore spaces at depths of 150-250 km, depositing crystals of essentially pure carbon. The gas in question is held to have been an original constituent of our planet and its movement is interpreted as part of the continuing planetary outgassing process. Gas of identical origin can be called upon to account for the violent puncturing of the earth's crust by khmberlite diatremes and the safe ferrying of the rapidly cooled diamonds through a large vertical pressure/temperature region in which slow passage would doom the diamonds to reversion to ordinary carbon.