Scripps Institution of Oceanography research geologist Robert L. Fisher's papers, correspondence, professional materials, research files and writings.

Robert Lloyd Fisher (b. 1925) is a Research Geologist Emeritus in the Geosciences Research Division at the Scripps Institution of Oceanography (SIO). He is known as a leading contributor to the field of deep-sea geology, with significant lifelong contributions to the areas of seafloor exploration and cartography, sub-oceanic igneous crustal composition and structure, and trench tectonics in the Pacific and Indian oceans. Fisher earned a B.S. in Geology from Caltech in 1949 and a Ph.D. in Marine Geology from UCLA in 1957 (with all research completed at the SIO campus). Active at sea from 1951 to the early 1980s, Fisher was a participant in, and chief scientist of, many major deep-sea geological-geophysical expeditions from SIO. In the 1950s and 1960s he used sound-train analyses from subsurface bomb detonations and innovative echo-sounding practices to determine the depths of deepest-ocean trenches. Fisher was among the first to recognize Challenger Deep in the Mariana Trench as the deepest locality in the world's oceans, as well as finding Horizon Deep in the Tonga Trench, slightly less, to be the deepest point in the Southern Hemisphere. A dexterous mapmaker, Fisher's participation in SIO's Vermilion Sea Expedition to the Gulf of California in 1959 produced a bathymetric chart in 1961 which foreshadowed later plate tectonic patterns. Pioneering the theory of subduction, the 1954 two-ship CHUBASCO Expedition in the Middle America Trench established that at trenches the "oceanic" crust above the mantle creeps diagonally into the mantle beneath the landward flanks "continental" layers by convective action.

47 Linear feet (47 cartons, 25 films, 1 map case folder, 54 map case drawers, 284 rolled charts)

Publication rights are held by the creator of the collection.

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