New developments in diamond geology

Research paper by J. B. Dawson

Indexed on: 01 Dec '83Published on: 01 Dec '83Published in: The Science of Nature


New occurrences of kimberlite are reviewed together with the occurrences of diamond in nonkimberlitic volcanic rocks, in xenoliths within kimberlite and in orogenic peridotites occurring within fold mountain belts; and the various types of inclusions found within diamonds are then reviewed. Various arguments for the two main hypotheses of diamond formation (phenocrystal v. xenocrystal) are presented and it is concluded that diamonds are not precipitated from ascending melts. It is also concluded that diamond may form in a wide range of chemical environments and that the speed of ascent for the preservation of diamond during its ascent to the surface from its stability field depth is perhaps not as important as formerly believed.