Menard, Henry William

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MENARD, HENRY WILLIAM

(b. Fresno, California, 10 December 1920; d. La Jolla, California, 9 February 1986),

marine geology.

H. William Menard, informally known as Bill, was one of several scientists who led the systematic mapping of the deep oceans after World War II. This was the first detailed study of most of the Earth’s surface, and one that, by leading to plate tectonics, revolutionized geology.

Early Years. Menard grew up in Los Angeles with his adoptive parents Henry William and Blanche, attending the California Institute of Technology (Caltech) as a geology undergraduate. He joined the Naval Reserve in 1941, going on active service in photo interpretation and intelligence after graduation in 1942. After the war he returned to Caltech for an MS, and then moved to Harvard for a PhD for a study of sedimentation, in which he applied the kind of simple quantitative methods he would use throughout his career.

In 1949, Menard returned to California to join the Sea-Floor Studies section of the Naval Electronics Lab in San Diego, where he studied bathymetry and marine sediments, combining navy soundings and data collected on oceanographic expeditions, many done jointly with the Scripps Institution of Oceanography (SIO), where he became a part-time lecturer in 1951 and full-time (and lifelong) faculty member in 1955. This exploration of the oceans by a few institutions was the first attempt to map the geology and topography of some very large regions, in Menard’s case, much of the Pacific.

An example of what could be found was Menard’s discovery, on his first deep-sea expedition in 1950, of an undersea mountain range (the Mid-Pacific Mountains) and of the Mendocino fracture zone, a large straight feature of rough topography offsetting seafloor of different depths. With data from subsequent surveys Menard located more of these features, all approximately parallel, in the northeast Pacific.

Deep-Sea Sedimentation. Menard’s initial work in marine geology was a rethinking of deep-sea sedimentation, pointing out that the notion of an undisturbed sea floor wasinvalid, and invoking turbidity currents as a major source of sediments. The discovery of the fracture zones, which were unlike anything known on land, turned his attention to describing and explaining the source of these and other large-scale ocean features. Between 1950 and 1965, Menard, with other SIO scientists, led deep-sea expeditions to all parts of the Pacific, gradually refining what was known about this part of the ocean. After an initial focus on the fracture zones, in the late 1950s he became as interested in the oceanic rises, both the existing East Pacific Rise and possible previous rises shown by the existence of drowned islands. Always ready to try a new hypothesis, Menard attempted several syntheses of the known ocean data using temporal changes within a fixed pattern of continents and oceans. These summary accounts made many of the findings of oceanography available to a wider audience of geologists, and culminated in the book Marine Geology of the Pacific (1964), which unfortunately became largely obsolete soon after publication, when the new concepts of seafloor spreading and plate tectonics-very largely based on marine geology-completely changed the paradigm for understanding the ocean floor.

Though Menard had played no role in developing these new concepts, he was quick to adopt them and to realize how important they were. Having (by his own account) accepted the basic ideas by late 1966, over the next few years he and his students used magnetic, geological, and bathymetric data to determine the history and origin of many features of the northeast Pacific, an activity that had major implications for the understanding of the geology of western North America. The northeast Pacific, with faster spreading and more obvious complexities than the Atlantic, could not be explained through constant spreading. With his students, Menard extended concepts of seafloor spreading to include variations in spreading direction and changes in the nature of plate boundaries.

Though plate tectonics explained much, there were still topics it did not address, and much of Menard’s research from the 1970s until his death was devoted to these areas, in particular the record of uplift and subsidence preserved in islands and submarine mountains. By combining his wide knowledge of particular instances with new concepts such as uplift by flexure from nearby loads and reheating of the lithosphere, he continued to address long-standing questions about the origins of high atolls and guyots, a topic described for the general reader in his last book, Islands (1986).

Menard’s interests extended well beyond his professional specialty, notably to areas such as resource availability, shown in his work on manganese nodules, and later on a novel evaluation of the efficiency of exploration for oil. In 1974 he published a textbook discussing geology and resources. These wider interests also led him to an episode of public service, as director of the U.S. Geological Survey from 1978 through 1981.

Menard also had a strong interest in the history of geology, about which he wrote several articles and two books. The first book, Science: Growth and Change (1971) grew out of his year (1965-1966) at the White House Office of Science and Technology, and examined patterns of scientific growth and how these affected different branches of science and those who pursued them, andshowed how subfields of geology had grown at very different rates. The other book, The Ocean of Truth (1986), was a combined memoir and history of marine geology and continental drift, describing how the explorations that Menard and others had led had provided convincing evidence for continental drift and plate tectonics. Menard’s interest in making his science known to the public was expressed through popular articles and a book (Anatomy of an Expedition, 1969) describing what it was like to explore at sea. These works show his considerable wit, also present (though more muted) in his professional writings.

Menard’s achievements brought him wide recognition, including election to the National Academy of Sciences in 1968, and the William Bowie Medal of the American Geophysical Union in 1985.

Menard brought to all of the areas he studied a zest and enthusiasm for research, and a desire to share his findings, that was a pleasure to those who worked with him at sea and ashore. He married Gifford Merrill in 1946; they had three children.

BIBLIOGRAPHY

With Robert S. Dietz. “Mendocino Submarine Escarpment.” Journal of Geology 60 (1952): 266-278.

“Deformation of the Northeastern Pacific Basin and the West Coast of North America.” Bulletin of the Geological Society of America 66 (1955): 1149-1198.

“The East Pacific Rise.” Science 132, no. 3441 (1960): 1737-1746.

With Tanya Atwater. “Changes in Direction of Sea Floor Spreading.” Nature 219 (1968): 463-467.

With Marcia K. McNutt. “Evidence for and Consequences of Thermal Rejuvenation.” Journal of Geophysical Research 87 (1982): 8570-8580.

The Ocean of Truth: a Personal History of Global Tectonics. Princeton, NJ: Princeton University Press, 1986.