Robert S. Dietz; Geologist Studied the Ocean Floor

Robert S. Dietz, 80, a geologist known for his pioneering studies of the ocean floor. As a civilian scientist with the Navy, Dietz led the oceanographic research effort on Admiral Richard E. Byrd’s last Antarctic expedition in 1946-47. In 1952, he authorized the purchase of the first scuba gear from France, and Navy researchers and colleagues from the Scripps Institution of Oceanography in La Jolla subsequently made the first offshore geological map of the sea floor. In the late 1950s, Dietz collaborated with Swiss engineer Jacques Piccard in developing the bathyscaph Trieste for ultra-deep sea diving. Dietz planned the 1960 voyage of the Trieste and its two-man crew to the world’s lowest point in the Pacific--a seven-mile-deep dive that has yet to be duplicated. Only last year did a robotic Japanese vessel return to the area. In Tempe, Ariz., on May 19 of a heart attack.