Experimental Petrology: An Indoor Approach to an Outdoor Subject

Experimental petrology is concerned with the laboratory study of reactions designed to elucidate petrological processes. The term includes experiments dealing with the physical properties or physical chemistry of minerals, rocks, rock melts, or of vapors, gases or solutions coexisting with solid or molten materials. Much of the impetus for experimental petrology has come from the efforts of geologists to understand the origin of igneous and metamorphic rocks. These rocks provide "fossil" records of the processes involved in the development of mountain ranges and the formation of continents, processes which are surface manifestations of changes occurring within the mantle. On the basis of standard geological, structural, and petrological investigations of rocks exposed at the surface of the earth, petrologists propose hypotheses about the processes involved in the origin of rocks at depth. Experimental petrology provides one means of testing the relative merits of various hypotheses by permitting the reproduction in the laboratory of high pressures and temperatures similar to those involved in the natural processes.