RICHARD L. HAY: THE IMPORTANCE OF HIS WORK ON ZEOLITES AND ZEOLITE REACTIONS IN SEDIMENTARY ROCKS

Richard L. Hay's work on zeolites in tuffaceous rocks was truly seminal. He taught us how to integrate modern analytical technology with careful geologic observation. He showed us what previously had been described as glass devitrification was in fact a chemical reaction between volcanic glass and fluids; and, that the composition of the glass and fluids determine the initial and subsequent reaction products. These findings were demonstrated with exceptional clarity in his work at Teels Marsh, Nevada; Owens, China; Kramer and Searles Lakes, California; Lake Natron and Olduvai Gorge, Tanzania; Green River Formation, Wyoming; and, the Lockatong Formation of New Jersey. Most importantly, Dick Hay demonstrated to his colleagues that with respect to anthigenesis/diagenesis, pH, salinity, and cation content of water can produce mineralogical effects comparable to diagenetic and/or metamorphic mineral changes resulting from increasing temperature and pressure during burial. We take this fact for granted today; but, in the early 1960s, it was a highly contentious suggestion.

Very quickly, Hay's seminal work of the 1960s was extrapolated to the study of tuffaceous rocks from a wide variety of sedimentary environments to sandstone diagenesis, to pelagic marine and carbonate sediments. An explosion of knowledge and a massive reduction of uncertainty with regard to anthigenetic/diagenetic processes characterizing a wide variety of sediment types and environments resulted. Every scientist working on anthigenesis or diagenesis of sediments has positively benefited from the work of Richard L. Hay. Those of us who worked with Dick in the period 1960-1990 were privileged to associate with an outstanding scientist and a great teacher. The number of people benefiting from contact with Dick is too many to list; but, we all agree that Dick was characterized by the traits that make a truly exemplary and special geologist.