CONCEPTUAL GEOLOGIC MODEL and NATIVE STATE MODEL of the ROOSEVELT HOT SPRINGS HYDROTHERMAL SYSTEM D. D. Faulder Idaho National E

Total Page:16

File Type:pdf, Size:1020Kb

CONCEPTUAL GEOLOGIC MODEL and NATIVE STATE MODEL of the ROOSEVELT HOT SPRINGS HYDROTHERMAL SYSTEM D. D. Faulder Idaho National E PROCEEDINGS, Sixteenth Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, January 23-25, 1991 SGP-TR-134 CONCEPTUAL GEOLOGIC MODEL AND NATIVE STATE MODEL OF THE ROOSEVELT HOT SPRINGS HYDROTHERMAL SYSTEM D. D. Faulder Idaho National Engineering Laboratory P. 0. Box 1625, Idaho Falls, ID 83415-2107 ABSTRACT A two-dimensional reservoir model of the A conceptual geologic model of the Roosevelt hydrothermal system is used to investigate the Hot Springs hydrothermal system was devel oped conceptual model and the physical constraints by a review of the available literature. The of the system. The native state simulation hydrothermal system consists of a meteoric study tests the conceptual geologic model and recharge area in the Mineral Mountains, fluid establishes reservoir boundary conditions. As circulation paths to depth, a heat source, and the simulation study progresses, the conceptual an outflow plume. A conceptual model based on geologic model provides a reference for the available data can be simulated in the adjusting reservoir parameters. native state using parameters that fall within observed ranges. The model temperatures, GEOLOGY recharge rates, and fluid travel times are sensitive to the permeability in the Mineral The RHS geothermal system is located on the” Mountains. The simulation results suggests the eastern edge of the Basin and Range presence of a magma chamber at depth as the physiographic province and at the transition likely heat source. A two-dimensional study of between the Colorado Plateau and the Basin and the hydrothermal system can be used to Range. The geothermal system lies to the west establish boundary conditions for further study of the batholith of the Mineral Mountains, the of the geothermal reservoir. first range west of the Wasatch Front. The Mineral Mountains are a north-south trending INTRODUCTION horst bounded by Basin and Range normal faults. A geologic map of the area is given in Figure The Roosevel t Hot Springs (RHS) hydrothermal 2. system was the site of an active exploration program starting in 1974. A 500’F liquid- Eruptive History dominated reservoir was discovered through The Mineral Mountains intrusive complex has a exploration drilling in 1975. The Roosevelt history of magmatic activity since the Hot Springs Unit (RHSU) was formed in April Oligocene time (Neilson et al., 1986). The 1976 and was the first geothermal unit approved oldest phase began about 25 Ma with intrusives by the United States Department of Interior. into Precambrian rocks. This pluton was then .A 25 MW, geothermal power plant started intruded by the main intrusive complex about 22 operations in 1984. The location of the study Ma. About 9.0 to 9.6 Ma an igneous sequence area is shown in Figure 1. was emplaced. The earliest volcanic activity occurred 7.9 Ma along the west side of the The Roosevelt Hot Springs area has been used as range. The final volcanic episode started in a natural laboratory for the development and the Twin Peaks volcanic complex about 2.7 Ma testing of geothermal exploration and with the eruption of rhyolite domes and eval uat i on methods, involving geologic, widespread basalt flows. The last rhyolitic geophysical, geochemical, and reservoir volcanism occurred between .8 and .5 Ma and testing. A literature review for the RHS resulted in twelve domes in the central Mineral system reveals over 180 geoscience titles. Mountains and the Bailey Ridge rhyolite flow These many sources were used to develop a just east of the reservoir. Chemical conceptual geologic model of the hydrothermal similarity of all the domes suggests they were system. derived form the same magma source (Ward et al., 1978). Structure This work was prepared for the U.S. Department The structural geology of the RHS has been of Energy under Contract No. DE-AC07-79ID01570. studied by many workers. A brief description of the features that follows draws upon the work of Nielson et al. (1978), Ward et al. (1978), Bruhn et al. (1982), Ross et al. (1982), Nielson et al. (1986), and Nielson -131- (1989). The commercial geothermal reservoir is strike of the contacts between igneous and closely associated with the Negro Mag and Opal country rocks. The joint spacing varies from Dome Faults. Structural features are important 3 to 95 feet to less than two inches in areas in controlling the reservoir characteristics of intense faulting. A third joint set and boundaries. consists of gently to moderately westward dipping joints generally having smooth planar The Negro Mag Fault is an east-striking, high surfaces with a joint spacing varying from angle, oblique slip with significant right greater than 3 feet to 4 inches in highly lateral shear fault. This range cutting fault faulted areas. The joint system in the is the major driving fault defining local Precambrian rocks is similar to the pluton. active structures and is active into the deep basement. The Negro Mag Fault is located along Geophysics the axis of a complex graben structure 4 miles The surface heat flow map of the area clearly across. This graben forms a low in the crest shows the location of the shallow geothermal of the Mineral Mountains, separating a reservoir, (Figure 3). Surface heat flow above Pleistocene rhyolite dome complex to the south the known reservoir is greater than 1000 from lower and more dissected ground containing mW/m- , with a large plume extending to the no rhyolite domes to the north. The Bailey northwest, (Wilson and Chapman, 1980). Ridge rhyolite appears to have erupted from Continuation with depth of the heat flow data faults associated with this graben, suggesting shows an eastward extension along the Negro Mag the structure has been present since at least fault. The large plume northwest of the the early Pleistocene. intersection of the Negro Mag and Opal Dome Faults is associated with outflow from the The highly conspicuous Opal Mound Fault is a geothermal reservoir. The regional heat flow north-south normal fault marked by alluvial is 92 mW/m-*, while heat flow measured jt depth .scarps, surface alterations, and opaline from the Acord 1-26 well was 146 mW/m- (East, deposits which attest to geologically recent 1981). activity and extensive leakage ofthe reservoir along this feature. The Opal Dome Fault The total aeromagnetic intensity residual map separates a graben to the east from a narrow of the RHS area shows the dominance of east- horst to the west. west features that cut the Mineral Mountains and extend east into the Beaver Valley, Low- to moderate-angle denudation faults occurs reflecting the structure at depth. throughout the Mineral Mountains, but are most common in the geothermal area. The faults dip Gravity modeling and filtering by Becker (1985) between 5" and 35" to the west with an indicates an anomalous gravity low centered estimated maximum depth of formation of 16,000 13,000 - 20,000 feet below the reservoir with feet (Bruhn et al., 1982). These low-angle a density contrast of approximately -.15 g/cc. faults developed after the emplacement and This result closely corresponds to work by consolidation of the Tertiary pluton 'complex Robinson and Iyer's (1981) investigation of P- and pre-date rhyolite domes and flows dated at wave structure of the crust and uppermost 0.5 Ma. mantle. Their work showed a clear pattern of relatively low velocity (5 to 7 per cent less The older, low-angle faults consist of up to than the surrounding rock) materi a1 extending 650 feet zone of cataclasis separating rocks of up from the upper mantle to a depth of about the Mineral Mountains intrusive complex from 16,000 feet under the west side of the Mineral overlying sedimentary rocks. The Cave Canyon Mountains. This plume is centered near the Fault represents this style of faulting. geothermal area, but extends to the north and south at depth. The degree of velocity change A second series of listric normal faults occurs modeled would indicate a temperature increase cutting principally rocks of the Mineral of about 1080" to 1,530°F, indicating for Mountains intrusive complex. The Wildhorse typical crustal rocks some degree of melting. Canyon and Salt Cove Faults are representative of this style of faulting. The Wildhorse Pre-productionmicroseismic monitoring detected Canyon Fault is a continuous feature on the several episodic east-west swarms south of the west side of the Mineral Mountains. This Negro Mag Fault, (G. Zandt and D. Nielson, feature contains a number of NW, high angle written communication). Focal depths were cataclasite zones up to 12 feet thick in hills clustered at two distinct depths of 10,000 feet south of Big Cedar Cove. The Salt Cove Fault and 26,000 feet. The interval in-between was is a similar, parallel structure, east of the aseismic. The microseismicity demonstrates the Wi 1 dhorse Canyon Fault . Negro Mag graben system is still active, see Figure 2. The joint system through the central Mineral Mountains is relatively homogenous and consists of three major joint sets. Two sets of steeply dipping, sub-orthogonal extension joints trend northward and eastward, occurring roughly parallel and perpendicular to the -132- Geochemistry A aquifer test was made in well 26-9-18. The The thermal waters were by characterized test results indicate a permeability of 1560 Capuano and Cole (1982) as a dilute sodium mD, assuming an aquifer thickness of 320 feet chloride brine, with approximately 7000 mg/l (Vuataz and Goff, 1987). The thickness of the total dissolved solids. The Na-K-Ca and Si0 principal aquifer west of Negro Mag Wash varies geothermometers indicate deep geothermaf from greater than 500 feet west of the temperatures of 466" and 550'F for the reservoir to 100 to 300 feet in the center of Roosevelt seep and deep well fluid samples, Mi 1 ford Val 1 ey (Mower and Cordova, 1974).
Recommended publications
  • Beaver County, Utah Resource Management Plan
    BEAVER COUNTY, UTAH RESOURCE MANAGEMENT PLAN Beaver County Commissioners Michael F. Dalton, Chair Mark S. Whitney Tammy Pearson Planning & Zoning Commission Darrel Davis, Chairman Kyle Blackner, Administrator Von Christiansen, Attorney Jamie Kelsey, Secretary Steve Kinross Mike Riley Walter Schofield Kolby Blackner Drew Coombs Don Noyes Public Lands Keven Whicker, Public Lands Administrator County Staff Scott Albrecht, Michelle Evans, Tracy McMullin, Heidi Eyre Adopted June 6, 2017 (ordinance 2017-03) Amended December 17, 2019 (ordinance 2019-06) i TABLE OF CONTENTS INTRODUCTION .......................................................................................................................... v LEGAL BASIS FOR COUNTY RESOURCE MANAGEMENT PLANNING .......................... ix SOCIAL-ECONOMIC LINKAGES ............................................................................................. xi CURRENT RESOURCE MANAGEMENT SETTING .............................................................. xv DESIRED RESOURCE MANAGEMENT SETTING .............................................................. xvii 1. LAND USE ............................................................................................................................. 1 2. ENERGY, MINING, MINERAL & GEOLOGICAL RESOURCES .................................... 9 2.1 Mining and Mineral & Geological Resources .................................................................. 9 2.2 Energy Resources ...........................................................................................................
    [Show full text]
  • A History of Beaver County, Utah Centennial County History Series
    A HISTORY OF 'Beaver County Martha Sonntag Bradley UTAH CENTENNIAL COUNTY HISTORY SERIES A HISTORY OF 'Beaver County Martha Sonntag Bradley The settlement of Beaver County began in February 1856 when fifteen families from Parowan moved by wagon thirty miles north to Beaver Valley. The county was created by the Utah legislature on 31 January 1856, a week before the Parowan group set out to make their new home. However, centuries before, prehistoric peoples lived in the area, obtaining obsidian for arrow and spear points from the Mineral Mountains. Later, the area became home to Paiute Indians. Franciscan Friars Dominguez and Escalante passed through the area in October 1776. The Mormon settlement of Beaver devel­ oped at the foot of the Tushar Mountains. In 1859 the community of Minersville was es­ tablished, and residents farmed, raised live­ stock, and mined the lead deposits there. In the last quarter of the nineteenth century the Mineral Mountains and other locations in the county saw extensive mining develop­ ment, particularly in the towns of Frisco and Newhouse. Mining activities were given a boost with the completion of the Utah South­ ern Railroad to Milford in 1880. The birth­ place of both famous western outlaw Butch Cassidy and inventor of television Philo T. Farnsworth, Beaver County is rich in history, historic buildings, and mineral treasures. ISBN: 0-913738-17-4 A HISTORY OF 'Beaver County A HISTORY OF Beaver County Martha Sonntag Bradley 1999 Utah State Historical Society Beaver County Commission Copyright © 1999 by Beaver County Commission All rights reserved ISBN 0-913738-17-4 Library of Congress Catalog Card Number 98-61325 Map by Automated Geographic Reference Center—State of Utah Printed in the United States of America Utah State Historical Society 300 Rio Grande Salt Lake City, Utah 84101-1182 Contents ACKNOWLEDGMENTS vii GENERAL INTRODUCTION ix CHAPTER 1 Beaver County: The Places That Shape Us .
    [Show full text]
  • Ground-Water Resources of Selected Basins in Southwestern Utah
    Utah State Engineer Technical PubUcation No. 13 GROUND-WATER RESOURCES OF SELECTED BASINS IN SOUTHWESTERN UTAH By G. W. Sandberg Hydraulic Engineer U. S. Geological Survey Prepared by the U. S. Geological Survey in cooperation with The Utah State Engineer 1966 CONTENTS Page Abstract _ __ _ _.................. 5 Introduotion _................................................................................................... 6 Purpose, scope, and method of investigation _... 6 Location __ _ _ 7 Previous investigations _............... 7 Topography and drainage _............... 7 Geology _..................... 9 Climate 9 Well-numbering system 11 Acknowledgements 11 Ground Water 11 Recharge __.. ___..__.. _ 11 Occurrence _............... 14 Movement _.................... 16 General pattern of movement _........... 16 Movement between valleys 17 Winn gap 17 Iron Springs gap _............................ 18 Twentymile gap _ _................. 18 Beaver River canyon ___ _........... 18 Change in pattern of movemenL.................................................... 18 Seasonal changes _ _................... 18 Long-term changes 19 Discharge , _ _..................... 19 Natural discharge _................................ 19 Springs and seeps __ _........... 19 Evaporation and transpiration.............................................. 20 Subsurface outflow _.. __ __ _................ 21 Discharge from wells __ _.......................... 21 Flowing wells _ 21 Pumped wells __ _._ _...................................... 21 Stock wells _._ _
    [Show full text]
  • Position Outreach Announcement
    USDA FOREST SERVICE INTERMOUNTAIN REGION, R4 FISHLAKE NATIONAL FOREST Fishlake N.F (435) 896-9233 FAX (435) 896-9347 Competitive Detail-District Assistant Fire Management Officer GS-0462-08/09 The Fishlake National Forest will soon be recruiting for a Competitive Long-Term Detail (12 Months) District Assistant Fire Management Officer GS-0462-08/09. This is a competitive detail and will have a tour of duty of 12 months with an option to extend to 24 months. Travel costs will be negotiated. Position Description: This position serves as the District Assistant Fire Management Officer responsible for the suppression program on the Beaver Ranger District. This position is responsible for one Type 6 engine (E-631) and one Wildland Fire Module (Tushar Mountain). The DAFMO position works with the U.S. Forest Service, Bureau of Land Management, Bureau of Indian Affairs, National Park Service, U.S. Fish and Wildlife Service, and the State of Utah. The area involved includes federal, state, tribal and private lands. The DAFMO is responsible primarily for planning and direction of the fire detection, wildland fire preparedness and suppression support activities located within the Beaver Ranger District. This position requires a unique combination of skills and experience. To be successful, candidates should: · Be energetic, resourceful, self-motivated, organized, and able to think outside the box · Exhibit excellent oral and written communication skills · Enjoy and embrace work in a team atmosphere, but have an ability to work independently · Take pride in being a steward of public lands and enjoy working with a diverse public · Represent the Forest Service in a professional manner and be responsible, honest, and accountable This work is performed both in an office and field going setting and requires working for long hours under emergency situations.
    [Show full text]
  • Water Resources of Beaver Valley, Utah
    Water-Supply Paper No. 217 tai.{J; DEPAETMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMITH, DIRECTOR WATER RESOURCES OP BEAVER VALLEY, UTAH BY WILLIS T. LEE WASHINGTON GOVERNMENT PRINTING OFFICE 1908 CONTENTS. Page. Introduction _______________________________ 5 Location and extent of the area examined_-_-_____ 5 Purpose and scope of work_ _________________ _ __ 5 Cooperation __________________________ _-____ __ 6 Geography ___________________ ______________-- 6 Plateau province ______________________________- 6 Basin province ________________________________ 6 Deserts ___________________________________ 6 Isolated basins _____________________________ 8 Residual lakes___________________. ______ ,___ 8 Drainage __________________________________ 9 Geology ___________________ ___________ __________ 9 Formations_________________________________ 9 Granite ____________________________________ 9 Paleozoic sediments ________________________ 11 Effusive rocks________________________________ 11 Younger sediments_____________________ 12 Structure _____________________________________ 13 Water supply______________________________________ 15 Precipitation __________..________..____________ 15 Surface waters _____________________________ 17 Source______________________________________ 17 Measurements of flow_______________________ 18 Utilization ___________________________________ 19 Underground waters ______________________________ 19 Springs ___________________________________ 19 Number and distribution_______________________
    [Show full text]
  • Igneous Activity and Deposits in the Western and Southern Tushar
    Igneous Activity and DepositsA ' in__ the Western and Southern Tushar Mountains, Marysvale Volcanic Field, West-Central Utah Multiple:i--- Episodesjt of" Igneoust^y Activity,/ Mineralization,, and Alteration in the Western Tushar ^ountains, Utah Geologic History and Uranium Potential of the Big John Caldera, Southern Tushar Mountains! Utah i U.S* OEOLOGlCJsI, SUHVEY PROFESSIONAL FAJPfiR Igneous Activity and Related Ore Deposits in the Western and Southern Tushar Mountains, Marysvale Volcanic Field, West-Central Utah THOMAS A. STEVEN, Editor Multiple Episodes of Igneous Activity, Mineralization, and Alteration in the Western Tushar Mountains, Utah By CHARLES G. CUNNINGHAM, THOMAS A. STEVEN, DAVID L. CAMPBELL, CHARLES W. NAESER, JAMES A. PITKIN, and JOSEPH S. DUVAL Geologic History and Uranium Potential of the Big John Caldera, Southern Tushar Mountains, Utah By THOMAS A. STEVEN, CHARLES G. CUNNINGHAM, and JOHNJ. ANDERSON U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1299-A, B UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1984 UNITED STATES DEPARTMENT OF THE INTERIOR WILLIAM P. CLARK, Secretary GEOLOGICAL SURVEY Dallas L. Peck, Director Library of Congress Cataloging in Publication Data Main entry under title: Igneous activity and related ore deposits in the western and southern Tushar Mountains, Marysvale Volcanic Field, west-central Utah. (Geological Survey Professional Paper; 1299) Includes bibliographical references. Supt.ofDocs.no.: I 19.16:1299-A, B 1. Rocks, Igneous Utah Tushar Mountains. 2. Ore-deposits Utah Tushar Mountains. I. Cunningham, Charles G. II. Series. QE461.I426 1984 552'.1'0979246 83-600337 For sale by the Branch of Distribution U.S. Geological Survey 604 South Pickett Street Alexandria, VA 22304 CONTENTS [Letters designate the chapters] (A) Multiple episodes of igneous activity, mineralization, and alteration in the west­ ern Tushar Mountains, Utah, by Charles G.
    [Show full text]
  • GEOLOGICAL SURVEY P ROFESSION a L PAPER 1149 Cenozoic Stratigraphic and Structural Framework of Southwestern Utah
    GEOLOGICAL SURVEY P ROFESSION A L PAPER 1149 Cenozoic Stratigraphic and Structural Framework of Southwestern Utah By PETER D. ROWLEY, THOMAS A. STEVEN, JOHN J. ANDERSON,am/ CHARLES G. CUNNINGHAM GEOLOGICAL SURVEY PROFESSIONAL PAPER 1149 A summary of the Cenozoic sedimentary and volcanic stratigraphy of southwestern Utah, and the structures that controlled deposition of the strata and that displaced these strata UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1979 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY H. William Menard, Director Library of Congress Cataloging in Publication Data Main entry under title: Cenozoic Stratigraphic and Structural Framework of Southwestern Utah (Geological Survey Professional Paper 1149) Bibliography: p. 17 1. Geology, Stratigraphic Cenozoic. 2. Geology-Utah. I. Rowley, Peter D. II. Series: United States Geological Survey Professional Paper 1149 QE690.C438 551.7'8f09792 79-17228 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 024-001-03227-9 CONTENTS Page Abstract -- ——— — - —— - ——————— —— ———— ——— -- ———— ——— ———— -- 1 Introduction - —————— ———— - ———— —— — ——— —— - ———— ——— ———— —— 1 Acknowledgments — —— ————————— — ——— ———— ———— —————————————— 2 Stratigraphy - —————— ——— ———— —— - ————————— - ———— ——— ————————— 3 Lower Tertiary (and Upper Cretaceous?) sedimentary sequence ———————————————— 4 Middle Tertiary volcanic sequence —— —————— ——— ———— —————————————— 5 Early (pre-Needles Range Formation)
    [Show full text]
  • Hydrology of the Beaver Valley Area, Beaver County, Utah, with Emphasis on Ground Water
    STATE OF UTAH DEPARTMENT OF NATURAL RESOURCES Technical Publication No. 63 HYDROLOGY OF THE BEAVER VALLEY AREA, BEAVER COUNTY, UTAH, WITH EMPHASIS ON GROUND WATER by R. W. Mower, Hydrologist U.S. Geological Survey Prepared by the United States Geological Survey in cooperation with the Utah Department of Natural Resources Division of Water Rights 1978 CONTENTS Page U.S. customary-to-metric conversion factors. .......................................... VI Abstract .................................................................. 1 Introduction. ............................................................... 2 Well- and spring-numbering system. ............................................ 2 Physiography and drainage .................................................. 2 Hydrogeology. .......................................................... 4 Climate. .............................................................. 6 Previous investigations. .................................................... 8 Acknowledgments. ....................................................... 9 Water resources. ............................................................. 9 Volume of precipitation. ................................................... 9 Surface water. .......................................................... 11 Ground water. .......................................................... 12 The principal ground-water reservoir. ....................................... 14 Occurrence. ........................................................ 15 Hydraulic properties
    [Show full text]
  • GEOTHERMAL BIBLIOGRAPHY of UTAH — 2011 Stephanie Earls and Robert Blackett Utah Geological Survey January 2012
    GEOTHERMAL BIBLIOGRAPHY OF UTAH — 2011 Stephanie Earls and Robert Blackett Utah Geological Survey January 2012 INTRODUCTION This document contains bibliographic citations of geothermal‐related information for Utah representing publications released through 2010. The bibliography supports the American Association of State Geologists’ initiative to build the National Geothermal Data System. A separate, digital version of this bibliography, available on‐line through the National Geothermal Data System (www.stategeothermaldata.org), was created as a searchable index in spreadsheet format with links to other on‐line sources. This bibliography is preceded by the compilation of Budding and Bugden (1986), which was later updated through 2000 by Blackett and Wakefield (2002). The citations listed here were extracted from Budding and Bugden (1986), Blackett and Wakefield (2002), and the following sources: • WorldCat • GeoRef • Utah State Library • Google/Google Scholar • Utah Geological Survey Geology Bibliography of Utah • U.S. DOE Energy Database • OSTI Geothermal Technologies Legacy Collection • Annotated & Indexed Bibliography of Geothermal Phenomenon • University of Utah publications • Brigham Young University publications • Utah State University publications • U.S. Geological Survey publications • Utah Geological Survey publications • Graduate theses/dissertations • Geothermal Resources Council publications • Geothermal Energy Association • International Geothermal Association • Stanford University Geothermal Program • Southern Methodist
    [Show full text]
  • Joint Patterns in the Mineral Mountains Intrusive Complex and Their Roles in Subsequent Deformation and Magmatism
    JOINT PATTERNS IN THE MINERAL MOUNTAINS INTRUSIVE COMPLEX AND THEIR ROLES IN SUBSEQUENT DEFORMATION AND MAGMATISM by John M. Bartley Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah Link to supplemental data download: https://ugspub.nr.utah.gov/publications/misc_pubs/mp-169/mp-169-c.zip Appendix Miscellaneous Publication 169-C Utah Geological Survey a division of UTAH DEPARTMENT OF NATURAL RESOURCES This paper is part of Geothermal Characteristics of the Roosevelt Hot Springs System and Adjacent FORGE EGS Site, Milford, Utah. https://doi.org/10.34191/MP-169 Bibliographic citation: Bartley, J.M., 2019, Joint patterns in the Mineral Mountains intrusive complex and their roles in subsequent deformation and magmatism, in Allis, R., and Moore, J.N., editors, Geothermal characteristics of the Roosevelt Hot Springs system and adjacent FORGE EGS site, Milford, Utah: Utah Geological Survey Miscellaneous Publication 169-C, 13 p., 1 appendix, https://doi.org/10.34191/MP-169-C. Joint patterns in the Mineral Mountains intrusive complex and their roles in subsequent deformation and magmatism C1 JOINT PATTERNS IN THE MINERAL MOUNTAINS INTRUSIVE COMPLEX AND THEIR ROLES IN SUBSEQUENT DEFORMATION AND MAGMATISM by John M. Bartley ABSTRACT Granitic rocks intersected by drill holes in the Utah FORGE site in Milford Valley strongly resemble the Oligocene-Miocene Mineral Mountains batholith and belong to the same structural block as the Mineral Mountains. Thus, the Mineral Mountains batholith and the FORGE reservoir may share the same joint pattern. Fractures in the Mineral Mountains plutonic complex were mapped in seven 0.03–0.08 km2 areas in the northern half of the range to document orientations, spacing, continuity, intersection relationships, and orientations of slickenlines where present.
    [Show full text]