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THOMAS SEWARD LOVERING May 12, 1896-April 9, 1991 BY HAL T . M O RRI S INNOVATIVE FIEED AND laboratory studies of the relations of hycirothermally alterec! wall-rocks to minable ore clepos- ~ts were the principal scientific contributions of T. S. Lovering cluring an illustrious career that also incluclec! theoretical analysis, laboratory research, teaching, en c! administrative cluties in the fielcis of economic geology en c! geochemistry. For more than forty years he was affiliates! with the U.S. Geological Survey in cletailec! investigations of mining clis- tricts en c! mineralizec! terranes chiefly in Coloraclo en c! Utah. During the latter half or so of his USGS career, he often servec! as a U.S. clelegate to mineral conferences through- out the world and as a minerals consultant to other federal civilian en c! military agencies. To many who knew him only casually from his penetrating questions en c! discussions at scientific meetings and symposia, he sometimes appeared brusque, argumentative, en c! perhaps egocentric. To his close associates en c! co-workers, however, he was invariably cour- teous, generous, and steadfast in his support and friend- ship. To him the search for scientific excellence was para- mount en c! all else was secondary. Tom, as he was known by his colleagues en c! a wicle circle of both older and younger acquaintances, was born in St. Paul, Minnesota, on May 12, IS96. During World War I he 177

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178 B I O G RA P H I C A L EMOIRS trainee! as a Navy aviation caclet, but the armistice was signet! before he was transferred to combat cluty, en c! upon his discharge in 1919 he enterer! the Minnesota School of Mines. In 1922 he gracluatec! with an E.M. degree en c! later in the same year enrollee! in the graduate school of the University of Minnesota, where he receiver! an M.S. degree in geology in 1923 en c! a Ph.D. in economic geology in 1924. While at Minnesota he was strongly influencec! by Professors Frank F. Grout en c! John W. Gruner with whom he maintainer! an infrequent correspondence for many years. Tom's first position after completing his doctorate was an instructorship in the Department of Geology at the Univer- sity of Arizona. He remainec! at Arizona for only one aca- demic year, accepting a position in 1925 with the U.S. Geo- logical Survey to conduct studies of selected mining districts in the Coloraclo Front Range uncler the general supervi- sion of B. S. Butler. In 1934 he gave up this full-time posi- tion with the USGS and became an associate professor of geology at the University of Michigan. During the following eight academic years, he also undertook many laboratory investigations en c! worker! cluring the summer months for the USGS in Coloraclo, where he continues! his studies of tungsten en c! base- ant! precious-metal mining districts en c! participates! in regional mapping projects. Upon the entry of the United States into World War II, Tom took a leave of absence from Michigan en c! rejoinec! the USGS on a full-time war service appointment to assist in the Strategic Minerals Program. His wartime activities incluclec! the completion of several cletailec! reports on mining districts in Coloraclo en c! the early phases of what became a Tong-range study of deeply concealed ore bodies and associ- atec! surficial alteration zones in the East Tintic mining district of central Utah. At the ens! of Woric! War II, Tom returnee! to the Univer .

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TH O MAS S EWARD L OVE RI N G 179 sity of Michigan, where he resumed his professorship in the Department of Geology and Mineralogy for the 1946-47 aca- demic year. By this time, however, his field research at East Tintic had reached a critical phase, and in ~ 947 he re- signed from the faculty at Michigan and accepted a perma- nent assignment with the Mineral Deposits Branch of the USGS. He remained in this position until his retirement in 1966 at age seventy. During his retirement years he contin- ued to pursue both academic and research activities for nearly two decades, including the authorship of a number of scientific papers, teaching, mineral deposits consulting activities, and worldwide travel. Within about a month of reaching his ninety-fifth birthday he succumbed to leuke- mia on April 9, 1991, at his residence in Santa Barbara, California. Tom Lovering made significant contributions in several disciplines of geological science, including geologic map- ping, ore deposits studies, geochemistry, and the thermo- dynamics and cooling rates of igneous intrusions. He is probably most widely remembered for his studies of the geochemistry of magmatic hydrothermal wall-rock alteration in the Boulder County tungsten and gold district in Colo- rado and the East Tintic mining district in Utah. These studies have helped clarify the general processes of ore depo- sition and in a number of instances have provided direct guides to the occurrence of concealed ore deposits. When Lovering undertook his alteration studies in Boul- der, Colorado, in the 1930s, it was generally believed that the altered salvages of the tungsten- and gold-bearing ore shoots were created by wall-rock reactions with a single hy- drothermal solution that concurrently deposited the ore and gangue minerals. Tom was able to show, however, that the wide outer zone of strongly argillized (cIay-mineral rich) wall rock gives way abruptly near the ore shoots to a zone

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80 B I O G RA P H I C A L EMOIRS of sericitic alteration, which inclicatec! a change from early strong acic! solutions to near neutral solutions. These neu- tral solutions were then follower! in turn by weakly alkaline fluids from which the goicI, tungsten, en c! associates! gangue minerals were clepositecI. To further refine his hypothesis of the wiclely differing compositions of wall-rock altering solutions as comparer! to ore depositing solutions, Lovering undertook a cletailec! study of Utah's East Tintic mining district in the early 1940s. In this district hycirothermal wall-rock alteration zones aclja- cent to en c! above large replacement ore bellies are greatly more extensive than the relatively narrow seIvages borcler- ing the Bouicler County veins. In aciclition, some well-cle- fined geologic events, including minor faulting and igne- ous intrusions en c! eruptions, couIc! be user! to establish the relative timing of surges of the various altering solu- tions. The early results of his studies in East Tintic were published in 1949 as Monograph I by the Society of Eco- nomic Geologists. In this report he describes five distinct en c! separable periods of movement of magmatic hyciro- thermal fluids: First, an early district-wide flooding by neutral, magnesium-rich re- ducing solutions that dolomitized limestone wall-rocks and locally propylitized the basal parts of the earliest erupted lavas. Second, after a period of intrusion of minor bodies of monzonite and quartz-monzonite and the eruption of lavas, localized invasions of hot acidic solutions that severely leached and sanded the underlying limestones and hydrothermal dolomites, and strongly argillized the border areas of the minor intrusive plugs and the adjacent and nearby lavas. These argillized zones were comparable in many respects to the argillized envelopes of the Boulder County tungsten- and gold-ore shoots. Third, a multiple late-barren stage following closely in time on the mid-barren argillizing stage that is characterized in part by extensive silici- fication of carbonate rocks at depth and minor silicification of areas of lava and porphyry. Shortly following the silicifying solutions there was extensive

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TH O MAS S EWARD L OVE RI N G 181 flooding of near-neutral, sulfur-rich solutions that converted iron oxide minerals in the intrusive rocks, lavas, and some of the sedimentary rocks to cubic pyrite. Fourth, closely following the silicifying and pyritizing solutions, po- tassium-rich fluids moved along many of the channel-ways and conduits used by the preceding jasperoidizing solutions, converting some of the early-formed clay minerals to adularia, sericite, and illite. In most places minor clear quartz, pyritohedral pyrite, and sparse barite were deposited at this time. Fifth, a change in composition of the potassium-rich solutions at the source with the abrupt and increasing appearance of ore ions in the hydro- thermal solutions, eventually leading to the abundant precipitation of sul- fide, sulfantimonide, sulfarsenide, and other ore minerals that replace part of the early-formed jasperoid, sanded dolomite, and other fresh and al- tered rocks. Fluid inclusions entrapped within these ore and gangue min- erals indicate that they were deposited from near neutral, saline solutions at temperatures ranging from 150-300C. ~ 7 1~ ~ 1~ ~ 7 For Lovering the selection of the East Tintic mining clis- trict for his most clefinitive studies of hycirothermal wall- rock alteration was highly fortuitous, inasmuch as relatively few major mining districts elsewhere in the woric! show such a distinct sequential series of hycirothermal events leacling to ore deposition. Many other large districts are greatly complicated, in fact, by overprints of repetitive stages of solution activity, continues! igneous emplacement, en c! similar geologic events. Tom Lovering also was a lifelong acivocate of cletailec! geologic mapping, and he often expressed his personal ob- servation that theoretical en c! experimental studies were vaTic! only when closely linker! with meticulous fielc! exami- nations en c! clemonstrable physical relations. His geologic en c! alteration maps of the East Tintic district, publisher! in 1960 as U.S. Geological Survey Mineral Investigations Fielc! Studies Map MF-230, for example, were wiclely user! by pri- vate mining and exploration groups in the district, leading to the discovery en c! clevelopment of two major new mines

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82 B I O G RA P H I C A L EMOIRS en c! the clelineation of several other prospective zones that may be worthy of development. Tom was particularly prouc! also of his contributions to the geologic map of Coloraclo, which was publisher! in 1935 in collaboration with W. S. Burbank, E. N. GociciarcI, en c! E. B. Eckel, en c! his geologic maps of the Coloraclo Front Range en c! the Front Range mineral belt that accompany U.S. Geo- logical Survey Professional Paper 223, publisher! in 1950 with Eciclie GociciarcI. As an exception to his Tong-stancling rule to avoic! acimin- istrative en c! supervisory positions if at all possible, Tom agrees! in 1954 to become chief of the USGS Section of Geochemical Exploration. In large part this reflected! his cleeply hell! interest in the refinement en c! continues! cle- velopment of new mineral exploration techniques. On step- ping clown from this position in 195S, Tom servec! until his retirement as a senior research scientist within the Geo- logic Division, continuing his studies of the geochemistry of hycirothermal wall-rock alteration, innovative techniques of geochemical exploration, en c! worIc~wicle mineral resource evaluation. During his lifetime Tom receiver! many honors, inclucI- ing election to the National Academy of Sciences, the Dis- tinguishec! Service Mecial of the U.S. Department of the Interior, the Penrose Mecial of the Society of Economic Ge- ologists, the Tackling Mecial of the American Institute of Mining en c! Metallurgical Engineers, en c! the Achievement Awarc! Goic! Mecial of the University of Minnesota. He was an active member en c! supporter of numerous scientific en c! engineering societies, some of which include the American Association for the Advancement of Science, the American Geophysical Union, the American Association of Mining, Metallurgical, en c! Petroleum Engineers, the American As- sociation of Petroleum Geologists, the Clay Minerals Soci- ety, the Geochemical Society, the Geological Society of

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TH O MAS S EWARD L OVE RI N G 183 America, the Society of Economic Geologists, and, a par- ticular favorite of his, the Coloraclo Scientific Society. For approximately ten years after his retirement from the USGS Tom maintainer! a residence near the USGS regional headquarters in LakewoocI, Coloraclo, but spent many win- ters in Tucson, Arizona, where he later acceptec! a research professorship in economic geology at the University of Ari- zona. During this time he also taught special courses in economic geology at the University of Texas, University of Utah, en c! other academic institutions. In 1976 he mover! from Lakewooc! to Santa Barbara, California, where he be- came a research associate at the University of California, Santa Barbara. As with his other postretirement academic activities, this affiliation allowed! Lovering to interact with bright students en c! an outstanding faculty in the academic en c! research environment that he so greatly enjoyocI. Throughout the greater part of his years as a student en c! as a professional geologist Tom enjoyoc! the love, support, en c! companionship of his wife, Corinne. He marries! Alexina Corrine Gray on October Il. 1919, shortly after his clis- charge from the Naval Aviation Corps. She was no stranger to the rigors of geologic fieldwork en c! cheerfully acceptec! the discomforts of wilclerness camping in the Coloraclo Rockies, spartan lodgings in declining mining camps, and less than palatial accommodations in a wide variety of mo- tels en c! hotels in small towns throughout the west. Corrine cliec! on August 27, 1969. Fincling his life lonely en c! incom- plete in many ways without a close companion, Tom later marries! Milcirec! Stewart, with whom he sharer! many com- mon interests, especially extensive land and sea travel through- out the woricI. Millie also prececlec! him in cleath on March 13, 1983. Tom is survived by one son, Tom G. Lovering, a daugh- ter-in-law, Dorothy, en c! two grancichiTciren, Davic! en c! Karen.

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184 B I O G RA P H I C A L S E L E C T E D EMOIRS B I B L I O G RAP H Y 1923 The leaching of iron protores; solution and precipitation of silica in cold water. Econ. Geol. 18:523-40. 1927 Organic precipitation of metallic copper. U.S. Geol. Surv. Bull. 795:45- 52. 1928 Geology of the Moffat Tunnel, Colorado. Am. Inst. Min. Metall. (Engl. Trans.J 18:337-46. 1929 The New World or Cooke City mining district, Montana. U.S. Geol. Surv. Bull. 811:1-87. The Rawlins, Shirley, and Seminoe iron ore deposits, Carbon County, Wyoming. U.S. Geol. Surv. Bull. 811:203-35. 1932 Field evidence to distinguish overthrusting from underthrusting. 7. Geol. 40:651 -63. 1933 With J. H. Johnson. Meaning of unconformities in the stratigraphy of central Colorado. Am. Assoc. Pet. Geol. Bull. 17:353-74. 1934 Geology and ore deposits of the Breckinridge mining district, Colo- rado. U.S. Geol. Surv. Prof. Pap. 176. 1935 Geology and ore deposits of the Montezuma quadrangle, Colorado. U.S. Geol. Surv. Prof Pap. 178. Theory of heat conduction as applied to geological problems. Geol. Soc. Am. Bull. 46:87-100.

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TH O MAS S EWARD L OVE RI N G 185 With W. S. Burbank, E. N. Goddard, and E. B. Eckel. Geologic map of Colorado. U.S. Geol. Surv. Scale 1:500,000. 1936 Heat conduction in dissimilar rocks and the use of thermal models. Geol. Soc. Am. Bull. 47:87-100. 1938 With E. N. Goddard. Laramide igneous sequence and differentia- tion in the Front Range, Colorado. Geol. Soc. Am. Bull. 49:35-68. 1941 The origin of the tungsten ores of Boulder County, Colorado. Econ. Geol. 36:229-79. 1943 Minerals in World Affairs. New York: Prentice-Hall. 1947 Sericite-kaolin alteration as a guide to ore. In Report of the Com- mittee on Research on Ore Deposits of the Society of Economic Geologists. Econ. Geol. 42:534-35. 1948 With V. P. Sokoloff and H. T. Morris. Heavy metals in altered rocks over blind ore bodies, East Tintic district, Utah. Econ. Geol. 43:384- 99. 1949 With others. Rock alteration as a guide to ore East Tintic district, Utah. Econ. Geol. Monograph I. 1950 With E. N. Goddard. Geology and ore deposits of the Front Range, Colorado. U.S. Geol. Surv. Prof Pap. 223. The geochemistry of argillic and related types of alteration. Colo. Sch. Mines Q. 45:231-60.

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186 B I O G RA P H I C A L 1953 EMOIRS With O. L. Tweto. Geology and ore deposits of the Boulder county tungsten district, Colorado. U.S. Geol. Surv. Prof Pap. 245. 1954 Safeguarding our mineral-dependent economy. Geol. Soc. Am. Bull. 64:101-25. 1955 Temperatures in and near intrusions. In Economic Geology, 50th An- nual Volume, Part 1, ed. A. M. Bateman, pp. 249-81. 1958 Current developments in geochemical exploration. Pakistan f. Sci 10:28-33. 1959 Significance of accumulator plants in rock weathering. Geol. Soc. Am. Bull. 70:781-800. 1960 With A. O. Shepard. Hydrothermal alteration zones caused by halo- gen acid solutions, East Tintic district, Utah. Am. f. Sci. Bradley Vol. 258-A:215-29. With others. Geologic and alteration maps of the East Tintic dis- trict, Utah. U.S. Geol. Surv. Min. Invest. Field Studies Map MF-230, two sheets, Scale 1:9600. 1961 Sulfide ores formed from sulfide-deficient solutions. Econ. Geol. 56:68- 99. 1963 tpigenetic, diplogenetic, syngenetic, and lithogenic deposits. Econ. Geol. 58:315-31. 1965 With H. T. Morris. Underground temperatures and heat flow in the East Tintic district, Utah. U.S. Geol. Surv. Prof Pap. 504 F:F1-F28.

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TH O MAS S EWARD L OVE RI N G 1967 187 With C. Engel. Translocation of silica and other elements into Equi- setum and other grasses. U.S. Geol. Surv. Prof. Pap. 594 B:B1-B16. 1969 The origin of hydrothermal and low-temperature dolomite. Econ. Geol. 64:743-54. 1978 With O. L. Tweto and T. G. Lovering. Ore deposits of the Gilman district, Eagle County, Colorado. U.S. Geol. Surv. Prof Pap. 1017. 1979 With H. T. Morris. General geology and mines of the East Tintic mining district, Utah and Juab Counties, Utah. U.S. Geol. Surv. Prof.Pap. 1024.