HEEZEN, BRUCE C.

(b. Vinton, Iowa, 11 April 1924; d. at sea, south of Iceland, 21 June 1977)

oceanography.

Heezen was the son of Charles Christian Heezen and Esther Shirding. When he was still young, the family moved to Muscatine, iowa. As the only child of affluent parents, he was able to pursue his many interests in the outer world about him and the inner world of the laboratory and the library. Heezen was also called upon, in his younger years, to help his father and, in his father’s absence, to manage the family turkey farm.

Heezen enrolled at the University of Iowa in 1942, and as a geology major he worked closely with his professor, A.K. Miller, and Professor Arthur Trowbridge. After he spent a summer in Nevada as an assistant to Walter Youngquist, who was collecting cephalopods for his Ph. D. dissertation, Heezen’s future career as a paleontologist seemed assured. However, in April 1947, after hearing a Sigma Xi lecture by Maurice Ewing of the Woods Hole Oceanographic Institute on the perils and adventures of deep-sea exploration, Heezen went up to meet him. Ewing said to him, “Young man, would you like to go on an expedition to the Mid-Atlantic Ridge? There are some mountains out there, and we don’t know which way they run.” Heezen went, and spent the next thirty years mostly at Lamont Geological Observatory, under the direction of Ewing, working in the new, wide open, and rapidly expanding field of oceanography.

Heezen had a long, productive collaboration with Ewing. The team of Ewing, Heezen, and David Ericson was particularly effective in finding both ships and time to collect data to solve both specific and general problems in the analysis of deep-sea cores and the distribution patterns of sediments in the abyssal plains. Heezen’s work as expedition leader was a great challenge and joy to him, particularly in the early days, when every cruise was a voyage of discovery and there was freedom for the chief scientist to explore features of interest. His ability as a teacher developed through work with his graduate students, many of whom later occupied outstanding positions in academe, governmental service, and industry.

Heezen’s contributions to knowledge of the ocean floor included seafloor processes, structure and trends of the Mid-Oceanic Ridge, and the visual observation of the seafloor from both near and far. His first major work, undertaken with Ewing and Ericson soon after he arrived at Lamont, was concerned with turbidity currents. The Grand Banks earthquake of 1929 and the resulting series of cable breaks documented on a grand scale the existence of turbidity currents, a dense mixture of sand and seawater, and the speed with which they can race downslope and erode, transport, and deposit sands far out to sea. These coarse-grained sands formed abyssal plains on the ocean basin floor between the continental margins and the Mid-Oceanic Ridge. Turbidity currents are transport, and their deposits represent only a small percentage of deep-sea sediments; Heezen was ever concerned that there should be other processes involved in forming the seafloor.

An unexpected opportunity to study this problem arose in 1965 when a disabled winch and lost coring rig on an early cruise of the R.V. Eastward forced Heezen to revise his program completely. He did so, using a bottom camera with a compass and a short corer. The results of this study revealed the role that deep geostrophic contour currents, controlled by the Coriolis effect, play in the erosion, transportation, and deposition of sediments along the continental margins. These great wedges of sediment, smoothed out by deep currents flowing parallel to the contours, are now known as drifts.

Students and colleagues of Heezen—Charles Hollister, Leonard Johnson, and Anthony Laughton—further identified and surveyed many drifts in the North Atlantic and Pacific oceans, showing that these deposits are a major feature of the seafloor. Throughout his life Heezen continued to be interested in sedimentation as it related to pography and to the underlying geological structure.

A study of the topography of the North Atlantic using data obtained from the three Mid-Atlantic Ridge expeditions of 1947–1948 was begun by Heezen and Marie Tharp in 1952; they continued to work together until Heezen’s death in 1997. A simultaneous study of earthquakes as a cause of cable failures resulted in the discovery by Marie Tharp of the seismically active rift valley as a median feature in the 40, 000-mile, world-encircling Mid-Oceanic Ridge, This discovery of the rift valley was announced by Ewing and Heezen at the 1956 meeting of the American Geophysical Union in Toronto. Therift valley, which is tensional, has associated shear features or fracture zones. Although fracture zones were discovered in the Pacific by M.F. Maury in 1939, they were not known to exist in the Atlantic until 1961, when Heezen and Tharp discovered the equatorial fracture zones and recognized that they were not mere fracture zones but a major offset between two ridge segments.

Meanwhile, Heezen, knowing that the rift valley was tensional in nature, proposed that the earth expanded as new crust arose from within the rift valley. He also suggested that this expansion of the earth provided a mechanism for continental drift, Heezen first presented his idea in 1958 in a paper “Géologie sous-marine et déplacements des continents,” delivered at Nice, France. He continued to propose his expanding-earth hypothesis throughout the early 1960’s Although Heezen’s idea turned out to be incorrect, his idea of the creation of new seafloor material at the ridge axis was correct and a fundamental aspect of Harry Hess’s idea of seafloor spreading.

Heeezen’s concern with the. visual aspects of the seafloor covered a broad range of scales: from the distant view of the physiographic diagrams, 1:10 million (1957–1971), the panoramas of the several oceans (1967–1970), and the final “World Ocean Floor” panorama, 1:23 million (1977), to the bottom photographs taken from a surface ship 91971), and finally to actually observing the seafloor from manned submersibles.

In order to better portter portray the features of the seafloor, Heezen and Tharp adapted the sketching technique developed by A.K. Lobeck of Columbia University to portray land topography. The first of their physiographic diagrams of the North Atlantic was accompanied by a text. A succession of physiographic diagrams of the South Atlantic, Indian Ocean, and west central Pacific followed. These diagrams, plus others covering the world’s oceans, served as a basis for the panoramas prepared by the artist Heinrich Berann, who worked closely with Heezen and Tharp. The panoramas were published in National Geographic and brought a vivid and realistic picture of the seafloor to the general public. The “World Ocean Floor,” a panorama that was sponsored by the Office of Naval Research, was completed just before Heezen left on his last cruise.

Heezen’s interest in the near visual aspects of the seafloor had originated in 1947, during his first field season at sea. He had collected many bottom pictures and cores, which he published with John Northrop in 1951. His lifelong interest in the visual aspects of the floor of the ocean resulted in a book, The Face of the Deep (1971), written with Charles Hollister, in which the description of submarine topographic provinces and seafloor processes was accompanied by nearly 600 photographs of the deepsea floor. The publication of this book led directly to Heezen’s involvement as a principal participant in the U.S. Navy program investigating the deepsea floor with submersibles. This work helped assuage Heezen’s unquenchable curiosity about the actual appearance of the seafloor.

Heezen, who never married, died of a heart attack while he was aboard the U.S. Navy nuclear submarine NR-l to observe the crest of the Reykjanes Ridge. His death cut short further publication of his visual observations on tidal currents as an additional process in the initial formation of submarine canyons, descriptive bench and talus geology of the continental slope and canyon gorges, submarine karst topography in the Bahamas, volcanism at Puna Ridge off Hawaii, and subduction in the Middle America Trench.

Heezen received his Ph.D. from Columbia University in 1957. He was research associate (1956– 1958) and senior research scientist (1958–1960) at the university’s Lamont-Doherty Geological Observatory and then assistant professor (1960–1964) and associate professor (from 1964) in the department of geology. He served as a consultant to the U.S. Navy, submarine cable companies, and the oil industry, and was an adviser on the Law of the Sea. Among the many national and international organizations in which he took an active part were the Commission for Marine Geology of the International Union of Geological Sciences (president) and the Commission on Marine Geophysics of the International Association of the Physical Sciences of the Ocean (president). He was coordinator of the IUGGI Atlantic, Indian and Pacific Oceans of the Geological World Atlas.

Heezen was the recipient of the Henry Bryant Bigelow Medal (1964), the Cullum Geographical Medal of the American Geographical Society (1973) the Francis P. Shepard Medal of the Society of Economic Paleontologists and Mineralogists (1975), the Walter H. Bucher Medal of the American Geophysical Union (1977), and the Gardiner-Greene Hubbard Medal of the National Geographic Society, awarded posthumously to Heezen and to Marie Tharp (1978).

BIBLIOGRAPHY

1. Original Works. “An Outcrop of Eocene Sediment on the Continental Slope,” in Journal of Geology, 59 (1951), 396–399, written with John Northrop; “Turbidity Currents and Submarine Slumps, and the 1929 Grand Banks Earthquake,” in American Journal of Science, 250 (1952), 849–873, written with Maurice Ewing; “Mid-Atlantic Ridge Seismic Belt,” in Transactions of the American Geophysical Union, 37 (1956), 343, an abstract written with Maurice Ewing; Physiographic Diagrams of the North Atlantic; the South Atlantic; the Indian Ocean; and the Western Pacific (New York, 1957–1971), with Marie Tharp; “Oceanographic Information for Engineering Submarine Cable Systems,” in Bell System Technical Journal, 36 (1957), 1047–1093, written with C.H. Elmendorf; The Floors of the Oceans, I, The North Atlantic, Geological Society of America Special Paper no. 65 (New York, 1959), written with Marie Tharp and Maurice Ewing; “Géologie sous-marine et déplacements des continents,” in La topographie et la géologie des profondeurs océaniques (1959), 295–304; “The Rift in the Ocean Floor,” in Scientific American, 203, no. 4 (1960), 98–110; “Equatorial Atlantic Fracture Zones,” in Special Papers of the Geological Society of America, 68 (1962), 195–196, written with Marie Tharp and Robert D. Gerard; “Chain and Romanche Fracture Zones,” in Deep-Sea Research, 11 (1964), 11–33, written with E. T. Bunce, J. B. Hersey, and M. Tharp; “Shaping of the Continental Rise by Deep Geostrophic Contour Currents,” in Science, 152 (1966), 502–508, written with Charles D. Hollister and William F. Ruddiman.

Additional works include Quaternary History of the Ocean Basins (New York, 1967); Panoramas of the Indian Ocean, the Atlantic Ocean, the Pacific Ocean; and The Arctic Ocean, inserts in National Geographic (1967–1970), with Marie Tharp; The Face of the Deep (New York, 1971), written with Charles D. Hollister; World Ocean Floor (Washington, D.C., 1977), with Marie Tharp; as editor, Influence of Abyssal Circulation on Sedimentary Accumulations in Space and Time (Amsterdam, 1977); and “Visual Evidence for Subduction in the Western Puerto Rico Trench,” in Géodynamique des Caraïbes (Paris, 1985), 287–304, written with Wladimir D. Nesteroff, Michael Rawson, and R. P. Freeman-Lynde. Heezen’s professional papers and underwater films are at the Smithsonian Institution Archives.

II. Secondary Literature. A commemorative volume is R. A. Scrutton and M. Talwani, eds., The Ocean Floor: Bruce Heezen Commemorative Volume ( New York, 1982). See also Marie Tharp and Henry Frankel, “Mappers of the Deep,” in Natural History, 95 (October 1986), 48– 62.

Marie Tharp