Memorial to Thomas Ellison Mullens 1925-1975

LAWRENCE C. CRAIG U.S. Geological Survey, Denver Federal Center, Denver, Colorado 80225

Thomas Ellison Mullens, a Fellow of the Geological Society of America, was born at Lovington, New Mexico, on January 10, 1924. He died in Denver, Colorado, on May 12, 1975, after heart surgery. He is survived by his wife, Marjorie, and two daughters, Nancy and Barbara. Tom's parents, John and Frances Ellison Mullens, moved to Aspermont, Texas, shortly after his birth. His father died when Tom was about two years old. At a later date his mother married Archie B. Candler, and the family moved to Dallas, Texas, where Tom grew up and received most of his early schooling. Tom graduated from Dallas Technical High School in 1940 and entered the University of Texas with plans to major in chemistry. His education was interrupted by World War II, and from 1942 to 1946 he served in the U.S. Army Air Force as an armament officer, attaining the rank of captain. He returned to college in 1946, enrolling in Southern Methodist University, and in 1948 he received his B.S. degree in a com­ bined major in geology and chemistry. Tom continued at Southern Methodist University for an additional year of graduate work in geology. In the summers of 1947 and 1948 he served as field assistant to J. Fred Smith, Jr., and Claude C. Albritton, who were map­ ping in the Sierra Blanca area of West Texas. In later years, Tom’s reference to these instructors made clear the high esteem that he placed on these early geological associations. Tom was a resourceful and diligent geologist, who had the remarkable capacity to listen to and assimilate from his colleagues and to return his gain manyfold through the benefits of his observations and knowledge. In addition Tom possessed a unique ability to complete one job before starting another. These capacities—to encourage mutual ex­ change and to complete jobs—were reflected throughout his career as basic principles to his concept of the ethic of the working scientist. Mullens’s specialty and preference in work was the application of stratigraphic studies to mineral deposits of the western United States, and during his career he made contributions to the geology of the following mineral commodities: uranium-vanadium, lead, zinc, the heavy metals, and coal. He joined the U.S. Geological Survey full time in June 1949; his first assignment was to the Geologic Division uranium program that pre­ ceded the uranium boom of the 1950s. In this program he participated in regional stratigraphic studies, a team effort, for which his main responsibility was lithofacies studies of the major uranium-producing unit at that time in the Colorado Plateau. The study of the Salt Wash Member of the Morrison Formation, made in company with V. L. Freeman and under the general guidance of L. C. Craig and C. N. Holmes, was a pioneering effort to quantify facies data in a sequence of fluvial rocks over a large region; it provided basic support to the regional stratigraphic synthesis of these rocks and pro­ 2 THE GEOLOGICAL SOCIETY OE AMERICA vided a regional lithofacies setting for the uranium deposits. Tom played an important role in the development of methods and contributed unstintingly to all aspects of the stratigraphic program. Upon completion of this work, Mullens undertook a mapping project under the general supervision of J. Fred Smith, Jr., again in support of the Survey’s uranium pro­ gram; from July 1952 to December 1953 he completed mapping five 71/j-minute quad­ rangles in the Red House Cliffs area, a fairly inhospitable (and at that time a relatively inaccessible) part of southeastern Utah. During this work, Tom observed “dust storms on the San Juan River”—attesting to the high silt content of the river and the high temperatures, low humidity, and high wind velocity of the region. The mapping project lay between two well-known uranium mining districts and, although it did not lead to the discovery of any major producing mines, it helped to define the possibilities for uranium discovery and refined our knowledge of the stratigraphic relations of the upper Paleozoic and lower Mesozoic beds between these two districts. Tom’s versatility in the uranium program had been recognized and he then was called into the “front” office where he assisted with the administrative load in the Geologic Studies program of the Colorado Plateau for most of 1954. The pressures of a new program—the Defense Minerals Exploration Administration, which required competent geologic appraisal of uranium properties—diverted him to mineral appraisal work for a period of six months. In mid-1955, largely as a result of Tom’s desire to broaden his experience beyond Colorado Plateau uranium, he transferred to Wisconsin, where he studied the south­ western Wisconsin lead-zinc deposits, mapping (in quadrangle units) the lower Paleo­ zoic rocks and analyzing the data from several thousand drill holes. Mullens was con­ vinced by these studies that the structures associated with the lead-zinc deposits were the result of the emplacement of the deposits instead of being pre-existing structures that localized the ore deposits. In this project Tom was in contact with several economic geologists, including A. V. Heyl, Harry Klemic, A. F. Agnew, and W. S. West. Mullens transferred to the Conservation Division of USGS in 1960, and for three years he was involved in quadrangle mapping and the study of phosphate deposits in northeastern Utah. This study in an area of complex structure resulted in the division of a previously undivided sequence of orogenic conglomerates, in the recognition of contrasts in Paleozoic rocks across the Willard thrust fault, and in definition of the Cretaceous age of that thrust. In late 1963 Mullens became Geologic Map Editor for the Conservation Division’s Branch of Mineral Classification and devoted much of his time to processing maps and reports for publication. His competence and devotion to his work were rewarded in 1967 by a within-grade promotion. At this time Mullens transferred back to the Geologic Division of the USGS and participated in the Heavy Metals Program. For almost a year he studied and sampled Cretaceous and Tertiary conglomerates in northern Utah and southern Idaho. There followed almost four years of study in north-central Nevada of the stratigraphy, geo­ chemistry, and petrography of the gold-bearing Roberts Mountains Formation of Silurian and Devonian age. This work resulted in refinement of the age of the Roberts Mountains Formation, a new concept of the regional stratigraphy that indicated a westward marine regression during the Silurian, and collaboration in recognition that gold in the mineral­ ized areas was associated with epigenetic pyrite instead of carbonaceous material. Following the heavy metals studies, Mullens investigated the mineral resources of MEMORIAL TO THOMAS ELLISON MULLENS 3

the El Paso and Van Horn 2° quadrangles, Texas, and appraised enormous reserves of sulfur and talc and large reserves of molybdenum of marginal grade. In mid-1974, Tom began a study of the distribution of cobalt and nickel in the lead ore of the Viburnum trend, Missouri. Since his experiences in Wisconsin, he had been fascinated by midcontinent lead and zinc deposits. One of his last wishes was a couple of years to complete this work. He felt that he was on the track of another contri­ bution to the understanding of metallic resources of the country. Indeed, his progress in understanding the lead-zinc deposits is reflected in the comments of A. V. Heyl, who reported that Tom was a most inventive geologist and in a period of a few years became very knowledgeable—an authority—about Mississippi Valley lead-zinc deposits. Tom’s first love was the field. He was a superb and eager field companion. His close colleagues will not forget being awakened at 5 a.m. by the smell of brewing coffee, Tom’s self-appointed task to provide a pleasant start for the day. Nor will they forget that as the day became unbearably hot, Tom enjoyed it more and more. To many a panting Plateau colleague, it seemed that every long, steep slope of Triassic-Jurassic red beds was capped by Tom, who had arrived five minutes earlier, was comfortably waiting, and was filled with geological observations gained during the arduous traverse. He worked well both as a team member and as an individual research scientist, offering original ideas, testing them critically, and discarding them readily if they did not satisfy his rigorous tests. On the other hand, those ideas that survived his testing won his ardent and tenacious support. His keen and independent powers of observation commanded the deep respect of all associated with him. And he remembered what he observed. An in­ veterate reader, Tom was a source of geological information and a poor choice to bet against in almost any field. If he said that “Unheard-of Investment Trust” paid a 37-cent dividend—it did, and if he said the deepest oil test in “Bullfrog” County was X thousand and 7 feet—that’s where the drillers bottomed. Tom was highly revered by his colleagues, both as a friend and as a geologist. He had yet more to offer. His professional contributions and his presence are keenly missed.

SELECTED BIBLIOGRAPHY OF T. E. MULLENS

1955 (and others) Stratigraphy of the Morrison and related formations, Colorado Plateau region: U.S. Geol. Survey Bull. 1009-E, p. 125-168. 1957 (and Freeman, V. L.) Lithofacies of the Salt Wash Member of the Morrison Formation: Geol. Soc. America Bull., v. 68, no. 4, p. 505-526. 1958 Preliminary geologic map of the Clay Hills 2 NE quadrangle, San Juan County, Utah: U.S. Geol. Survey Mineral Inv. Field Studies Map MF-184. 1959 Preliminary geologic map of the Clay Hills 2 NW quadrangle, San Juan County, Utah: U.S. Geol. Survey Mineral Inv. Field Studies Map MF-185. ----- Preliminary geologic map of the Clay Hills 2 SW quadrangle, San Juan County, Utah: U.S. Geol. Survey Mineral Inv. Field Studies Map MF-186. 1960 Geology of the Clay Hills area, San Juan County, Utah: U.S. Geol. Survey Bull. 1181-S, p. S1-S32. 1963 (and Izett, G. A.) Geology of the Paradise quadrangle, Utah: U.S. Geol. Survey Geol. Quad. Map GQ-185. 1964 Geology of the Paradise quadrangle, Cache County, Utah: U.S. Geol. Survey Bull. 1181-S, p. S1-S32. THE GEOLOGICAL SOCIETY OE AMERICA

1964 (and Laraway, W. H.) Geology of the Devils Slide quadrangle, Morgan and Summit Counties, Utah: U.S. Geol. Survey Mineral Inv. Field Studies Map MF-290. ------Geology of the Cuba City, New Diggings, and Shullsburg quadrangles, Wisconsin and Illi­ nois: U.S. Geol. Survey Bull. 1123-H, p. 437-531. 1969 Geologic map of the Causey Dam quadrangle, Weber County, Utah: U.S. Geol. Survey Geol. Quad. Map GQ-790. ------(and Crittenden, M. D., Jr.) Cretaceous age of the Willard thrust fault, Weber County, Utah: Geol. Soc. America, Abstracts with Programs for 1969, Pt. 5, (Rocky Mountain Sec.), p. 57. ------Stratigraphy of lower Echo Canyon, northeastern Utah, in Geologic guidebook of the Uinta Mountains, Utah’s maverick range- Intermtn. Assoc. Geologists 16th Ann. F’ield Conf., 1969: Salt Lake City, Intermtn. Assoc. Geologists, p. 213-218. 1971 Reconnaissance study of the Wasatch, Evanston, and Echo Canyon Formations in part of northern Utah: U.S. Geol. Survey Bull. 1311-D, p. D1-D32. ------Revised correlation of some Carboniferous rock units in the Causey Dam quadrangle, Weber County, Utah, in Geological Survey research 1971: U.S. Geol. Survey Prof. Paper 750-D, p. D105-D107. 1972 (and Poole, F. G.) Quartz-sand-bearing zone and Early Silurian age of upper part of the Hanson Creek Formation in Eureka County, Nevada, in Geological Survey research 1972: U.S. Geol. Survey Prof. Paper 800-B, p. B21-B24. -... — (and Cole, T. H.) Geologic map of the northeast quarter of the Morgan 15-minute quadrangle, Morgan and Weber Counties, Utah: U.S. Geol. Survey Mineral Inv. Field Studies Map MF-304. ------(and Heyl, A. V.) Paleoaquifer system [disc.]: Econ. Geology, v. 67, no. 4, p. 532-533. 1973 (and Wells, J. D.) Gold-bearing arsenian pyrite determined by microprobe analysis, Cortez and Carlin gold mines, Nevada: Econ. Geology, v. 68, p. 187-201. ------Disseminated pyrite in latite porphyry at Texan Mountain, Hudspeth County, Texas: U.S. Geol. Survey Jour. Research, v. 1, p. 519-521. 1974 (and Laraway, W. H.) Geologic map of the Morgan 7’/2-minute quadrangle, Morgan County, Utah: U.S. Geol. Survey Mineral Inv. Field Studies Map MF-318. ------Stratigraphy and petrology of the Roberts Mountains Formation, north-central Nevada: U.S. Geol. Survey Prof. Paper (in prep.).

Printed in U.S.A. 5/77