Gilbert, Grove Karl
Gilbert, Grove Karl
(b. Rochester, New York, 6 May 1843; d, Jackson, Michigan, 1 May 1918)
geology, geomorphology.
Gilbert received the A. B. at the University of Rochester in 1862, having taken only one course in geology, which was taught by Henry A. Ward; he subsequently worked for the Ward Natural Science Establishment, which prepared and sold scientific materials to educational institutions, from 1863 to 1868. In 1869 he joined the second geological survey of Ohio as a volunteer assistant to J. S. Newberry. From 1871 to 1874 he was “geological assistant” on G. M Wheeler’s geographical and geological survey, conducted west of the 100th meridian.
On 2 December 1874 Gilbert joined John Wesley Powell’s Rocky Mountain geographical and geological survey, which five years later, on Powell’s recommendation, was combined with the other federal surveys to form the U. S. Geological Survey. Thus began the long and fruitful association of Powell, Gilbert, and Clarence Edward Dutton. Powell’s fecundity in ideas found its effective foil in Gilbert’s accurate observation and suspended judgment.
Powell’s doctrine of subaerial erosion and baselevel was developed by Gilbert with emphasis on lateral planation in Report on the Geology of the Henry Mountains (1877). Importing these ideas into humid regions, W. M. Davis formulated the concept of geographic cycles. Thus were founded the fundamental principles of a new subscience, geomorphology, although that name, introduced by Powell, did not come into general use until the 1930’s.
According to W. W. Rubey (p. 497), the essence of Gilbert’s ideas was the concept of graded streams—the concept that, either by cutting down their beds or by building them up with sediment, streams tend always to make for themselves channels and slopes that, over a period of years, will transport exactly the load of sediment delivered into them from above. From 1907 to 1909, at Berkeley, California, Gilbert gratified his desire for quantitative data by conducting flume experiments on the transportation of debris by running water. The 1905–1908 investigation of hydraulic-mining debris and its sedimentary effects in the Sacramento River drainage system and in San Francisco Bay is a dispassionate account of the great power of man as a geologic agent.
Gilbert explained the structure of the Great Basin as the result of extension. The individual “basin ranges” are the eroded upper parts of tilted blocks, which were displaced along faults as “comparatively rigid bodies of strata.” Gilbert analyzed Powell’s diastrophism into orogeny, or mountain formation, and epeirogeny, or regional displacement. He described Lake Bonneville, the gigantic Pleistocene ancestor of Great Salt Lake, and related the displaced Bonneville shorelines and the displaced proglacial shorelines of the Great Lakes to epeirogenic isostatic rebound.
Gilbert studied the Henry Mountains in 1875 and 1876. He was the first to establish that an intrusive body may deform its host rock. He emphasized that the crust of the earth is “as plastic in great masses as wax is in small.” But he exaggerated the fluidity of magma, and his laccoliths are now interpreted as “tongue-shaped masses... injected radially as satellites from stocks” (Hunt et al., p. 142).
Gilbert was the very antithesis of a temperamental, erratic genius. He was scrupulous in giving credit due others, careless about receiving his own. In his presidential address to the Society of American Naturalists in December 1885, entitled “The Inculcation of Scientific Method,” he stressed the importance of inventing and testing multiple hypotheses, maintaining: “The great investigator is primarily the man who is rich in hypotheses.
From January 1889 until August 1892 Gilbert served as chief geologist of the U.S. Geological Survey. His brilliant presidential address to the Philosophical Society of Washington in December 1893 gave cogent argument for the impact origin of craters on the moon. In 1899 he was a member of the Harriman expedition to Alaska.
BIBLIOGRAPHY
I. Original Works. The B. D. Wood and G. B. Cottle bibliography that follows the Mendenhall memorial (see below), pp. 45–64, has 400 entries and is nearly complete. Gilbert’s writings include Report on the Geology of the Henry Mountains, U. S. Geographical and Geological Survey of the Rocky Mountain Region (Washington, D. C., 1877; 2nd ed., 1880); Lake Boneville, Monographs of the United States Geological Survey, no. I (Washington, D. C., 1890): The Transportation of Débris by Running Water, United States Geological Survey Professional Paper no. 86 (Washington, D. C., 1914); Hydraulic-Mining Débris in the Sierra Nevada, Professional Paper no. 105 (Washington, D. C., 1917); and Studies of Basin-Range Structure, Professional Paper no. 153 (Washington, D. C., 1928).
II. Secondary Literature. W. C. Mendenhall, “Memorial to Grove Karl Gilbert,” in Bulletin of the Geological Society of America, 31 (31 Mar. 1920), 26–45, includes a portrait and lists Gilbert’s honors and biographical notices. W. M. Davis,”Biographical Memoir. Grove Karl Gilbert, 1843–1918,” in Biographical Memoirs. National Academy of Sciences, 21 (1926), 5th memoir, presented 1922, includes pictures of Gilbert. See also Joseph Barrell,”Grove Karl Gilbert, an Appreciation,” in Sierra Club Bulletin,10 , no. 4 (Jan. 1919), 397–399; and, in the same number, p. 438, a letter from E. C. Andrews, Australia, dated 30 Apr. 1913. The references cited in text are W. W. Rubey, “Equilibrium Conditions in Debris-Laden Streams,” in Transactions of the American Geophysical Union, 13 (June 1933), 497–505; and C. B. Hunt, assisted by P. Averitt and R. L. Miller, Geology and Geography of the Henry Mountains Region, United States Geological Survey Professional Paper no. 238 (Washington, D. C., 1953).
Ronald K. DeFord