Summary Mineral Resource Appraisal of the Richfield 1 °X2° Quadrangle
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U.S. GEOLOGICAL SURVEY CIRCULAR 916 Summary Mineral Resource Appraisal of the Richfield 1°X2° Quadrangle, West-Central Utah Summary Mineral Resource Appraisal of the Richfield 1°X2° Quadrangle, West-Cen.tral Utah By Thomas A. Steven and Hal T. Morris U.S.GEOLOGICAL SURVEY CIRCULAR 916 Department of the Interior DONALD PAUL HODEL, Secretary U.S. Geological Survey Dallas L. Peck, Director Free on application to the Branch af Distribution, Books and Open-File Reports Section, U.S. Geological Survey, Federal Center, Box 25425, Denver, CO 80225 CONTENTS Page Page Abstract . 1 Mineral Resources-Continued Introduction . 1 Epigenetic mineral Resources-Continued CUSMAP participants . 3 Mineralized areas associated with early Miocene Geology . 3 Mount Belknap Volcanics . 20 Geochemistry . 3 Miocene mineral deposits in the Mineral Moun- Geophysics . 3 tains . 21 Remote sensing . 3 Mineralized areas associated with middle Mio- Water resource studies . 4 cene Steamboat Mountain Formation . 22 CUSMAP products . 4 Mineralized areas associated with the middle Geology and ore deposits . 10 Miocene rhyolite of Gillies Hill . 22 Mineral resources . 11 Mineralized areas associated with late Miocene Syngenetic and diagenetic mineral resources . 11 silicic rocks in Kingston Canyon . 22 Epigenetic mineral resources . 16 Mineralized areas associated with Pliocene and Mineralized areas associated with Oligocene younger silicic rocks . 22 and early Miocene calc-alkalic rocks . 16 Mineralized areas near Cove Fort and Sulphur- Mineralized areas associated with early Miocene dale . 23 Blawn Formation . 19 Uranium in basin fills . 23 Unclassified mineral deposits . 23 ILLUSTRATIONS Page FIGURE 1. Index map of Utah showing location of Richfield 1 °X2° quadrangle . 1 2. Map showing major geographic features of the Richfield 1 °X2° quadrangle, Utah. Numbered circles indicate localities discussed in text and shown on figures 3 and 4 . 2 3. Map showing generalized geology and different geologic associations related to volcanogenic-hydrothermal mineralization in the Richfield 1 °X2° quadrangle, Utah . 12 4. Map showing mineral resource potential for volcanogenic-hydrothermal mineral deposits in the Richfield 1 oX 2 o quadrangle, Utah . 14 III SUMMARY MINERAL RESOURCE APPRAISAL OF THE RICHFIELD 1 ° x 2 ° QUADRANGLE. WEST -CENTRAL UTAH By Thomas A. Steven and Hal T. Morris ABSTRACT Each of the many identified centers of mineralization is discussed briefly in this report and an estimate made of its The mineral resource potential of the Richfield 1 °X2° resource potential. quadrangle, Utah, has been appraised using geological, geophysical, geochemical, and remote-sensing techniques. These studies have led to many publications giving basic data and interpretations; of these, a series of 18 maps at 1:250,000 and INTRODUCTION 1:500,000 scales summarizing aspects of the geology, geophysics, geochemistry, and remote sensing is designated the The Richfield 1 oX 2 o quadrangle in west-central CUSMAP (Conterminous United States Mineral Appraisal Pro Utah (figs. 1 and 2) has been studied as part of the gram) folio. This circular uses the data shown on these maps U.S. Geological Survey CUS111AP (Conterminous to appraise the mineral resource potential of the quadrangle. The oldest rocks exposed in the Richfield quadrangle are small United States Mineral Appraisal Program) pro patches of Early Proterozoic (1.7 billion years old) gneiss and gram in which multidisciplinary studies are used schist on the west side of the Mineral Mountains. These rocks to evaluate the mineral resource potential of presumably formed the basement on which many thousands selected quadrangles throughout the nation. This of meters of Late Proterozoic, Paleozoic, and lower Mesozoic CUSMAP appraisal of the Richfield quadrangle is sedimentary strata were deposited. These rocks were deformed during the Late Cretaceous Sevier orogeny when Precambrian limited to metallic and nonmetallic resources; coal, and Paleozoic strata in the western part of the quadrangle were oil and gas, and geothermal energy resources are thrust relatively eastward across Paleozoic and Mesozoic strata not considered. The Richfield quadrangle was in the eastern part of the quadrangle. Late Cretaceous and early chosen for study because. preliminary data in Tertiary highlands above the overthrust belt were eroded and dicated that parts of the area have high mineral much of the debris was deposited in broad basins east of the belt. Volcanism in Oligocene and earliest Miocene time formed resource potential, and because modern geologic an east·northeast-trending belt of calcalkalic volcanoes across studies, focusing in part on mineral resources, had the southern half of the quadrangle. In early Miocene time, the already been begun in several places. By expand composition of the volcanic rocks changed to a bimodal ing and integrating these local studies, and by assemblage of mafic rocks and high-silica alkali rhyolite that has been erupted episodically ever since. Syngenetic mineral resources developed during formation of both sedimentary and volcanic rocks. These include limestone and dolomite, silica-rich sandstone, metalliferous black shale, evaporite deposits, zeolite deposits, pumice, cinders and scoria, and evaporitic or diagenetic deposits in playa environments. Most of these deposits need to have markets established, or extraction and fabrication techniques developed, for them to be utilized. Most epigenetic deposits are of volcanogenic-hydrothermal origin. Deposits associated with calc-alkalic igneous activity I largely contain Cu, Ph, Zn, Au, and Ag, and occur in a variety UTAH I of types zoned around core intrusions. Younger deposits are I mostly associated with silicic igneous centers belonging to the I o Richfield bimodal mafic-silicic igneous association. Resources associated Richfield I with this latter group are likely to contain one or more of the quadrangle I I elements Mo, W, U, Sn, Be, and F, as well as Ph, Zn, Au, and I Ag. Alunite and kaolinite deposits are found at many mineral ized centers. Most epigenetically mineralized areas expose on I I ly the upper, near-surface parts of the different hydrothermal ______ _JI systems; most of whatever mineral deposits formed in these systems probably still exist at depth, awaiting discovery. Our conclusion is that many mineralized areas have excellent FIGURE I.-Index map of Utah showing possibilities for the occurrence of mineral resources. location of Richfield 1 oX 2 o quadrangle. 1 --,112°00' Sevier Desert rf ~~· ~,<::< 9-o<' ~ k!S ~IIi <:P<:> q_'~~ -® @ I .. G ® !e ~ .s J! ~ c: ~ 5: ~ @~ "' ~ ~cysvale ~ • Milford 8 ®~ @ ( :- ·$' ~ .... ~ $ <lj ) @I@ •::r @ ~ •::r 8 r@ "'~ @ lif <::>"'"' ®l ( \.@ i .} ~.. ~ ""' @ X-"'" J -o-;.t 'i \1! '<O"i ~~ 0 0 5 10 15 20 25 30 35 KILOMETERS I I I I I I I I FIGURE 2.-Map showing major geographic features of the Richfield 1 °X2° quadrangle, Utah, Numbered circles indicate localities discussed in text and shown on figures 3 and 4, bringing to bear other earth science disciplines, it geochemistry, and geophysics of the area. The ma has been possible to identify many areas favorable jor participants and their main fields of study are for the occurrence of mineral resources. In addi listed as follows: tion, basic geological, geophysical, and geochem ical parameters of important segments of the intersecting Cordilleran overthrust belt and GEOLOGY younger Pioche-Marysvale igneous and mineral belt have been determined. T. A. Steven (U.S. Geological Survey, Denver, Colorado) (Coor Many of the preliminary results of this study or dinator of CUSMAP studies), Geology of igneous rocks and of directly contributory precursor studies, as well economic geology in eastern half of quadrangle. Co-compiler as much of the basic data, have been published or of geologic map. released in open file as the studies progressed. This H. T. Morris (U.S. Geological Survey, Menlo Park, California), report is a brief summary designed to present the Geology of sedimentary rocks, and economic geology of the western half of quadrangle. Co-compiler of geologic map. general conclusions reached by the CUSMAP C. G. Cunningham (U.S. Geological Survey, Reston, Virginia), studies with respect to the mineral resource poten Geology and economic geology of the Tushar Mountains tial of the Richfield quadrangle. To maintain brev and adjacent areas. ity and present these conclusions without undue P. D. Rowley, (U.S. Geological Survey, Denver, Colorado) interruption in the narrative account, many of the Geology of the Sevier Plateau, Black Mountains, and ad jacent areas. supporting data and source references have been J. J. Anderson (Kent State Univ., Kent, Ohio, and U.S. Geo deliberately omitted. Those interested in such data logical Survey), Geology of the southern Tushar Mountains and sources should consult appropriate individual and Markagunt Plateau. references listed in the section entitled "CUSMAP M. N. Machette, (U.S. Geological Survey, Denver, Colorado), products" or the more comprehensive and well Geology of the Beaver basin. D. L. Nielson and B.S. Sibbett, (Univ. Utah Research Inst., documented summary by Steven and Morris Salt Lake City, Utah; not formally part of CUSMAP pro (1984, U.S. Geological Survey Open-File Report gram), Geology of the Mineral Mountains and adjacent 84-521). areas. The general level of erosion in the Richfield L. F. Hintze (Brigham Young Univ., Provo, Utah, and U.S. quadrangle is sufficiently shallow that only the Geological Survey),