Memorial to Alonzo Wallace Quinn 1899-1977

Memorial to Alonzo Wallace Quinn 1899-1977 MARLAND P. BILLINGS Department o f Geological Sciences, Harvard University, Cambridge, Massachusetts 02138 Alonzo Wallace Quinn, Professor of Geology, Emeritus, at Brown University, died on April 8, 1977, in Providence, Rhode Island, in his seventy-eighth year. Lon’s chief geological interests included the petrology, age, and origin of the rocks of the northern Appalachian Mountains, especially the late Paleozoic intrusives of Rhode Island, the pre-Pennsylvanian igneous and metamorphic rocks of southern New England, and the plutonic rocks of New Hampshire. Of his many geological accomplishments, the greatest was the completion of the map of the bedrock geology of Rhode Island, published in Bulletin 1295 of the U.S. Geological Survey in 1971, on a scale of 1:125,000. Geologic maps are the basic material for under standing the geology of the upper part of the crust. A formal mapping program in Rhode Island began in 1944, when the state arranged a cooperative program with the U.S. Geological Survey. Excellent topographic sheets, published as IV i' quadrangles on scales of one inch to 2,640 or 2,000 feet were available as base maps. Most of the geologic mapping was done by university personnel working as part-time employees of the Survey. As Lon pointed out in Bulletin 1295, Rhode Island is the only state for which the bedrock geological map is based on maps prepared on a scale of 1:31,680 or 1:24,000. He modestly failed to mention that he personally—sometimes with an associ ate—mapped 35% of the state. Successful geologic mapping, both bedrock and glacial, involves much more than recording the lithology and structure of individual exposures. Thousands of observa tions must be assembled into a systematic whole. Lon, of course, also had the problem of coordinating data from many quadrangles. Moreover, all geologic events had to be properly placed in the geologic time scale. The bedrock geology of Rhode Island, which is located in the Appalachian province, is especially difficult to unravel. Except for the Carboniferous rocks of the Narragansett Basin, covering about 20% of the state, the rocks are largely unfossili- ferous. The Upper Cretaceous rocks of Block Island are ten miles off the coast. The Middle Cambrian fossils near the entrance to Narragansett Bay were not discovered until 1974. Consequently, Lon had to rely on a few standard geological methods of cor relation: (1) lithologic similarity; (2) tracing of lithologic units; (3) like sequences; (4) ages relative to one another, especially the relations to the Carboniferous strata. Lon assigned the rocks of Rhode Island to six groups: (1) older metamorphic rocks, pre-Pennsylvanian and at least in part probably Precambrian; (2) older plutonic rocks, pre-Pennsylvanian; (3) alkalic igneous rocks of Mississippian(?) age; (4) Penn sylvanian rocks of the Narragansett Basin; (5) Pennsylvanian or post-Pennsylvanian granitic rocks; and (6) Upper Cretaceous rocks of Block Island. 2 Till: GKO LOGICAL SOCIETY OP AMERICA In the early fifties Lon realized that radiometric methods were indispensable in unraveling the geology, especially that of the pre-Pennsylvanian rocks. He initiated a program in cooperation with the U.S. Geological Survey to use the lead-alpha age (Larsen) method. The results were presented in a classic paper published in 1957. Sixteen determinations were made on seven plutonic rocks, fifteen on zircon, one on monazite. Later radiometric studies were made by other authors on these same rocks and other Rhode Island rocks, using the K-Ar and Rb-Sr methods. In Bulletin 1295 Lon skillfully compares the radiometric ages with the geologic evidence. In 1968 Lon and George E. Moore, Jr., who had also mapped the bedrock geology of about 35% of the state, published an important paper on the sedimentation, tectonism, and plutonism of the Narragansett Bay region. In Rhode Island there is a rare opportunity to compare the rank of metamorphosed coal with the grade of metamorphosed pelitic rocks. In the Narragansett Basin the metamorphic grade of the pelitic rocks increases toward the south and southwest, as the rocks pass through the chlorite, biotite, garnet, staurolite, and sillimanite isograds. In 1958 Quinn and Glass showed that the rank of the coal increases progressively to the south and southwest from high anthracite to meta-anthracite. Prior to his commitment to the geology of Rhode Island, Lon had worked exten sively in New Hampshire from 1932 to 1940. At the suggestion of Professor E. S. Larsen, Jr., he studied the geology of Red Hill near Lake Winnipesaukee in central New Hampshire. The oval-shaped stock, three miles in maximum dimension, consists chiefly of nephelite-sodalite syenite, with minor amounts of syenite and quartz syenite. This investigation was notable because Lon used a fluoroscope to help identify the feld- spathoids. A recent study of Red Hill has confirmed the accuracy of Lon’s mapping. In the early and middle thirties Kingsley and Modell published papers on the geology of the Ossipee and Belknap Mountains. Red Hill, the Ossipees, and the Belknaps extend into the Winnipesaukee quadrangle. A very active program to map the geology of New Hampshire by quadrangles was in full swing at the time. Lon under took to complete the mapping of the Winnipesaukee quadrangle. The Ossipees extend also into the Wolfeboro quadrangle, which Lon also undertook to map. The southern quarter of this area is occupied by the Merrymeeting Lake granite stock, which extends southward into the Alton quadrangle. Glenn Stewart, now state geologist of New Hampshire, was mapping that quadrangle. All this activity resulted in four publica tions, two quadrangle reports published by the state of New Hampshire, a paper com paring and contrasting the New Hampshire and White Mountain series, and a joint paper with Stewart on the Merrymeeting Lake area. Lon’s interest in the geology of New Hampshire continued throughout later years. At Brown University he had colleagues who were experts in radiometric age determina tions. From field evidence the White Mountains plutonic-volcanic series was known to be younger than the Lower Devonian but could not be dated more precisely. On the bedrock geological map of New Hampshire, published in 1955, the White Mountains series was dated as Mississippian(?), based on a supposed correlation with alkalic rocks of the Quincy-Blue Hills area near Boston. In the years 1958 to 1960 a series of significant papers showed that the Conway granite, a member of the White Moun tains series, is about 185 m.y. B.P. old (latest Triassic). It was then assumed that the entire series was of that age. But from a radiometric study of the whole series, Lon and his colleagues at Brown University concluded that the emplacement of the series extended over 100 m.y., occupying much of the Jurassic and Cretaceous. Lon’s first geological publication “The Normal Faults of the Lake Champlain Region” was based on his doctoral thesis at Harvard University (to which he had come MEMORIAL TO ALONZO WALLACE QUINN 3 because of his association with Kirtley F. Mather as an undergraduate at Denison University). Alonzo Quinn taught at Brown University for nearly forty years as an instructor, 1929-36; assistant professor, 1936-42; associate professor, 1942-51; and professor, 1951-68. He became Professor of Geology, Emeritus in 1968. He was chairman of the geology department from 1940-61. When he joined the department it consisted of one professor and an instructor. When he retired there were eighteen faculty members con stituting one of the most distinguished departments in the country. In his early days at Brown, Lon was of necessity a jack-of-all-trades, but in later years his teaching con centrated on petrology and economic geology. He served on numerous state committees dealing with the mineral and water re sources of Rhode Island. He was chairman of the Mineral Resources Committee from 1943-51 and a member of various water resources boards from 1951-67. Alonzo W. Quinn was born May 28, 1899, in Halltown, Missouri, the son of Llewellyn Wallace Quinn and Cora (Hubbard) Quinn. He was fond of recalling the move he and his parents made to Colorado in a covered wagon. After attending grade and high school in Longmont, Colorado, he went to Denison University, where he received his B.S. degree in 1924. He was a half-time assistant at Kansas University (1924-25), at State University of Iowa (1925-26), and an instructor at Williams College (1926-28). He was in residence at Harvard University in 1928-29 and received his Ph.D. degree in 1931. Lon worked during the summers for the Illinois Geological Survey (1926) and the U.S. Geological Survey in New Mexico (1929), Montana (1930), and Utah (1931). This experience with the U.S. Geological Survey in the Western United States was superb training for his later work in New England. He also worked for the U.S. Geological Survey in Massachusetts in 1943 and in Rhode Island from 1944 to 1967. In 1956 Lon received the Erasmus Haworth Distinguished Alumni Award from the University of Kansas and in 1967 an honorary D.Sc. from Denison University. He was a Fellow of the Geological Society of America, the Mineralogical Society of America, and the American Association for the Advancement of Science, and a Member of the American Geophysical Union, the Geochemical Society, and Sigma Xi. Lon was modest, soft-spoken, and easy to talk to. He never sought the limelight. Because of his quiet sense of humor he was a delightful person with whom to be associated, both in the field and in the office. Lon is survived by his wife Alice (Ripley), whom he married September 8, 1929; two daughters, Mrs.

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