Arizona Geology - Summer 1989azgeology.azgs.arizona.edu/.../arizona_geology/...The Arizona Geological Survey has made a major effort ... 2 Arizona Geology, vol. 19, no. 2, Summer1989

Investigations • Service It Information

Overview of the Geology and Mineral Resourcesof the Buckskin and Rawhide Mountains

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Lineated mylonitic rocks in metamorphic core complexes

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Figure 1. Map of Arizona showing the three physiographic provincesin the State and· the locations of lineated mylonitic rocks in metamor­phic core complexes. BUC =Buckskin Mountains; CR =Santa Catalina- Rincon Mountains; RAW = Rawhide Mountains; SAC = SacramentoMountains; SM =South Mountain; WH = Whipple Mountains.

areally extensive exposures of a detachment fault and itsmylonitic footwall.

Evidence of mineralization is abundant along the Buck­skin-Rawhide detachment fault, including economic deposits ofcopper and gold. Detachment-fault-related mineralization isnowhere better displayed in North America than in and aroundthe Buckskin and Rawhide Mountains. This type of miner­alization was first recognized in the southwestern United Statesin the late 1970's (Reynolds, 1980; Wilkins and Heidrick, 1982).

. The existence of geologically similar deposits has been proposed(continued on page 6)

Introduction

The Arizona Geological Survey has made a major effortduring the past 5 years to understand the geology and mineralresources of the Buckskin and Rawhide Mountains. The resultsof these studies and several studies by other geologists arepresented in the Arizona Geological Survey Bulletin 198, fromwhich the following text has been excerpted. This technicalbulletin, which is now in press, represents a major addition tothe geologic literature on the State and should be of interestto anyone concerned with the geology and mineral deposits ofwest-eentral Arizona.

by Jon E. Spencer and Stephen J. ReynoldsArizona Geological Survey

Crustal extension and compression, involving large hori­zontal movements of the Earth's crust, are major processesthat have shaped the crustal architecture of planet Earth.Compression has long been recognized as the chief architect ofmost mountain belts and is now moderately well understood. Incontrast, the contribution of extension to the structure of thecrust is less well understood because many extensional struc­tures were only recently recognized and because areas affectedby crustal extension are typically buried by sediments.

Cenozoic extension in western North America has left ageologic record that, for areas of extensional tectonism, is1.ffisurpassed in its visibility. Geologic features related toCenozoic extension are especially amenable to study in the aridsouthwestern United States where bedrock exposure approaches100 percent. Approximately 25 mountain ranges or groups ofr~ng:s in western North America are characterized by a dis­tInctlVe association of geologic features that defied interpreta­tion until the early 1980's. These ranges or groups of ranges~re commonly referred to as metamorphic core complexes. Dis­tmguishing features. include a major low-angle normal fault(r:ferred to as a detachment fault) that separates brittlelydIstended and generally highly faulted rocks above the faultfrom crystalline rocks below the fault that commonly have a9Tntly to moderately dipping mylonitic foliation. Most geolo­gIsts now interpret such faults and foliations as products ofarge-magnitude crustal extension. These distinctive featuresave been recently recognized in parts of Greece, China, andew Guinea, which indicates that Cordilleran metamorphic coremplexes are not idiosyncrasies of western North America

eology, but are general products of extensional tectonism. Theckskin and Rawhide Mountains, which are part of the Harcu­r metamorphic core complex in west-eentral Arizona (Rehrigd Reynolds, 1980), contain one of North America's most

Figure 1. Value of nonfue1 mineral production in the Southwest, 1987 and 1988. Backgroundphoto: View of the New Cornelia open-pit copper mine near Ajo, Arizona. This currentlyinactive mine is within the Ajo mineral district, which produced from 1899 to 1979, 6 billionpounds of copper, 19.7 million ounces of silver, 1.6 million ounces of gol4, 450,000 pounds ofmolybdenum, and 30,000 pounds of lead. Photo by Peter Kresan.

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internationaland consumerswas reached on arole for the forum and on inclep>endellcefrom the United Nations Conf€~rellCe onTrade and Development.

As in previous years, exploration forgold far outpaced that of other commod­ities both at home and abroad. Abouttwo dozen new gold mines began pro­duction in the United States during1988, and several established producersexpanded capacity. A number of domesticand international companies with gold­mining interests consolidated, merged, orspun off their mining operations intoindependent corporations devoted solelyto mining gold. Domestic production ofgold and silver increased. Althoughaveraging slightly higher during most ofthe year, price levels for gold and otherprecious metals declined toward yearend.

Zinc mine production in 1988 rose forthe second consecutive year after fallingcontinuously in the prior 6-year period.The increase was partly due to a full­year's production of coproduct zinc atprecious metal mines in the West. fA

The U.S. District Court of Appeals 0.,the District of Columbia ordered theEnvironmental Protection Agency (EPA)to relist six wastes from the smeltingand refining of aluminum, copper, ferro­alloys, lead, and zinc as hazardousunder subtitle C of the Resources Con­servation and Recovery Act (RCRA).The EPA was also ordered to reinterpretthe Bevill amendment to the RCRA. Thisamendment excludes wastes from the"extraction, beneficiation, and processingof ores and minerals" from regulationunder RCRA subtitle C until the needfor such regulation is studied. Althoughthe range of the amendment has beenclearly understood, its application toprocessing ores and minerals has beenless clear. Under the court order, theEPA p~oposed a list of wastes specifical-ly excluded as Bevill wastes. Those thatdo not fall under the Bevill exclusionwill be subject to regulation after therule is finalized.

The EPA was also evaluating a strict-er National Ambient Air Quality Stan­dard that would lower the content oflead in air and impose additional costson domestic lead smelters. The world'slargest producer of secondary lead an­nounced that it would convert its plant~to a new electrowinning process, thus~becoming the first U.S. lead firm tomove toward pollution-free technology.

Bureau of Mines,P.O. Box 18070, Pittsburgh, 15236.

The State summaries were preparedby State mineral officers from theBOM, in cooperation with the respectiveState mineral agencies. Individual sum­maries are also published separately asState Mineral Industry Surveys. Copiesare available from the respective Statemineral officers: Michael N. Greeley,201 E. 7th St., Tucson, AZ 85705 (Ari­zona, New Mexico, and Utah); Fred V.Carrillo, 1605 Evans Ave., Reno, NV89512 (California and Nevada); and JaneP. Ohl, Bldg. 20, Denver Federal Center,Denver, CO 80225 (Colorado).

u.s. Summary

The value of nonfuel mineral produc­tion in the United States increased 16percent in 1988, from $26.3 billion to$30.5 billion, due to higher demand andprices. Metals and industrial mineralsaccounted for 34 and 66 percent of thetotal value, respectively. The value ofmetal production surged 40 percent in1988, from $7.4 billion to $10.4 billion,whereas the production value of indus­trial minerals rose only 6 percent, from$18.9 billion to $20.0 billion.

Copper prices, driven by tight supplyand record-low stock levels, averagedmore than $1.00 per pound during 1988.

3000

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In 1988 the value of nonfuel mineralproduction in the Southwest· reached$9.9 billion, a 30.5-percent increasefrom the 1987 value of $7.6 billion (Fig­ure 1; Table 1). Production value inthe Southwest accounted for 32.6 per­cent of the total value for the Nation,estimated to be $30.5 billion in 1988.For the purposes of this article, theSouthwest includes Arizona, California,Colorado, Nevada, New Mexico, andUtah. In 1988 the Southwest boastedthe three leading producers of nonfuelminerals in the Nation: California,Arizona, and Nevada. Two other States,New Mexico and Utah, held the 10th and11th positions, respectively. Coloradoranked 27th in the Nation.

These preliminary figures were pub­lished by the U.S. Bureau of Mines(BOM), which has released State-by­State estimates of nonfuel mineral pro­duction for 1988. These estimates, basedon 9 months of data, have been pub­lished for the first time in one volume:State Mineral Summaries--1989. Thisreport is designed to be a companionvolume to another BOM publication,Mineral Commodity Summaries--1989,which contains national statistics on theproduction of 82 nonfuel minerals. Ex­cerpts from both volumes appear below.Single copies of each are free from thePublications Distribution Section, U.S.

2 Arizona Geology, vol. 19, no. 2, Summer 1989

Table 1. Value of nonfuel mineral production in the Southwest, measured by mine ship­ments, sales, or marketable production, including consumption by producers. All figuresare from the U.S. Bureau of Mines; totals for 1988 are preliminary estimates.

The EPA's National Effluent Guide­lines for gold-placer mining becameeffective on July 7, 1988. Studies bythe U.S. Department of the Interior

_indicate that up to 75 percent of the..... small placer mines will close if these

regulations are implemented.Demand for building and construction

materials, such as construction aggre­gate, gypsum, and cement, remainedstrong in 1988. Demand for cementnearly equaled that of the record estab­lished in 1987. Domestic productiondeclined slightly while imports continuedto make inroads into domestic markets.Imports of 17 million tons were slightlybelow the record level of 1987. Canada,Greece, Mexico, and Spain were theprincipal suppliers of the importedcement, accounting for 75 percent of theimports. Domestic cement-productioncapacity owned by foreign firms reached62 percent in 1988 compared with 22percent in 1981. For the first time, Jap­anese producers became owners of U.S.capacity by purchasing cement plants inArizona and southern California.

The crushed stone industry, continu­ing the healthy growth trend that beganin 1984, reported record production.The gypsum industry continued its strongperformance, but because of reduction innew housing construction, output was

fA.... slightly below the record high of 1987._ The EPA continued to analyze the

impact of the proposed ban and phaseoutof asbestos and asbestos products. Inearly 1988, the EPA released its regula­tory impact analysis, an assessment ofexposure to asbestos and nonasbestosfibers, and a profile of the nonasbestosfiber industry.

In September, the President signed aU.S.-Canadian free-trade agreement thatwill eliminate all tariffs and most non­tariff barriers between the two countriesby 1999, thereby creating the world'slargest open market. In 1987 U.S.-Cana­dian bilateral trade totaled $161 billion.

Trade expansion is expected to generate5-percent higher growth for Canada andup to 1-percent higher growth for theUnited States by the end of the century.For the United States, that translatesinto 750,000 jobs and $2.4 billion inexports. Canadian parliamentary approv­al of the agreement is required beforethe treaty can take effect.

Arizona

Arizona's mining industry rode awave of prosperity during 1988. Itsnonfuel mineral production rose sharplyduring the year to an estimated value of$2.83 billion (Table 2). This representsan increase of more than $1 billion, orabout 58 percent, over the 1987 value.The bulk of this increase is due to thestrong price received during the year forcopper, which accounts for more thanthree-fourths of the State's nonfuel min­eral value. The price of copper rosefrom an average of $0.825 per pound in1987 to an average of $1.20 per pound in1988. This price hike was attributed todiminished stocks and strong demand.

Ranking second nationally in thevalue of its nonfuel mineral production,Arizona continues to lead other Statesin the production of copper: in 1988 itproduced nearly two-thirds of the Na­tion's copper. Copper was recovered at12 principal operations. Copper produc­ers, strengthened by a favorable market,continued to cut costs, expand capacity,and acquire future reserves.

In 1988 Arizona also gained the leadposition in molybdenum production. Insharp contrast to the decline registeredlast year, production was greatly in­creased in 1988. Arizona's production ofthis coproduct and byproduct metal ac­counted for almost 50 percent of theNation's domestic supply.

The State retained its place amongthe top producers of bentonite, cement,gem stones, lime, rhenium, sand and

Table 2. Value of nonfuel mineral produc­tion in Arizona, measured by mine ship­ments, sales, or marketable production,including consumption by producers. Allfigures are from the U.S. Bureau of Mines;totals for 1988 are preliminary estimates.

gravel, silver, and sulfuric acid. Mostlead and silver were produced as byprod­ucts of copper or flux ores. Gold pro­duction increased 64 percent.

The nonmetallic mineral industry isvery diversified in Arizona. The 1988production value of the largest compo­nent, construction sand and gravel,placed Arizona fifth in the Nation forthis commodity. Cement and lime pro­duction contributed significantly to thetotal value of industrial minerals, whichexceeded $297 million. There was also aconsiderable increase in the productionof diatomite and salt.

Some 12,000 workers were employedin the Arizona mining industry in 1988.This figure, an increase over 1987,includes workers in the mineral fuelsindustry. About 75 percent of the totalwork force is in copper exploration andproduction.

Most exploration efforts in Arizonafocused on precious metals and leachablecopper. Claim-staking activity remainedmoderately strong during the year; Ari­zona ranked third among the States inthe number of active claims for all com­modities.

Construction began on a tailings re­cycling facility in Gila County. This

Arizona Geology, vol. 19, no. 2, Summer 1989 3

solvent-extraction/electrowinning (SX­EW) plant is designed to wash down apile containing 35 million short tons ofcopper-bearing mill tailings and recoverapproximately 125 million pounds of cop­per. The $20-million project, the firstof its kind in the United States, willlast about 8 years.

State officials and representatives ofthe mining community attempted to re­solve the questions raised by the 1987decision of the State Supreme Court,which declared that Arizona's land-leas­ing law was unconstitutional. During1988, negotiations were underway be­tween the State Land Commissioner andthree major lessees. These companiesoperate mines on State Trust lands andmake relatively large annual royalty pay­ments to the State. Meanwhile all newapplications for mineral leases were heldin abeyance. Late in the year, the U.S.Supreme Court agreed to hear an appeal.

California

California led the Nation in value ofnonfuel mineral production for the fifthyear in a row. The value of the com­modities produced was estimated to be$2.85 billion, a 12 percent increase from1987. California led all States in theproduction of asbestos, boron minerals,portland cement, diatomite, calcinedgypsum, rare-earth metal concentrates,construction sand and gravel, and tung­sten ore and concentrates. It was secondin the production of natural calciumchloride, gold, byproduct gypsum, mag­nesium compounds from seawater, andsodium compounds. Gold exploration inthe State increased as rising productionencouraged further exploration. Severalgold producers continued to expand theiroperations.

No-growth regulations and oppositionto new mining permits impeded miningactivities throughout the State. Gold­mining operations, sand-and-gravel quar­ries, and cement plants were amongthose whose operations were halted ordelayed. Initiatives to prohibit surface­mining operations were proposed in EIDorado, Mariposa, and Tuolomne Coun­ties. Mariposa County narrowly defeatedthis proposal in the fall election. TheState of California, pursuant to AB No.747, now requires that all existing sur­face-mining operations with vestedrights must have an approved reclama­tion plan by July 1,1990.

Colorado

The estimated value of nonfuel min­erals produced in Colorado in 1988 was$375 million, a O.5-percent decline from1987. Between 1985 and 1988, the re­opening of several old precious-metal

4

mines increased Colorado gold output by313 percent. In 1988 gold productionrose 21 percent to an estimated 215,000troy ounces. Silver output at Coloradomines, however, was down an estimated15 percent from 1987. Byproduct leadfrom gold and silver mining decreasednearly 18 percent from that of 1987.

Once again, Denver has become agold capital. More than 50 percent ofU.S. gold production is controlled by thetwo to three dozen companies of local,national, and international standingwhose headquarters or major offices arein or moving to the Denver area.

Exploration continued around the his­toric mining camps of Creede, CrippleCreek, Leadville, Silverton, and Summit­ville. Old tailings piles are increasinglybeing considered as sources of metals.

On the Western Slope, seven urani­um/vanadium mines were put back intoproduction in 1987-88. Colorado's solenuclear power plant, however, will beshut down before June 30, 1990 becauseof continuing technological problemssince its opening in 1976.

Construction materials for the pro­posed new Denver airport, beltway E­470, and other projects have included anestimated 8 to 12 million short tons offine and coarse aggregates and portlandcement. Portland and masonry-eementproduction and value, however, declinedslightly in 1988. Output of dimensionstone rose an estimated 13 percent, andvalue 7 percent, over 1987.

Crude gypsum production fell 10 per­cent from that of 1987. The agriculturalcommunity and the U.S. Soil and Conser­vation Service have been using smallgypsum blocks buried in the soil tomeasure moisture content and reduceground-water pollution, soil erosion, andsalt buildup. Such an inexpensive methodof water conservation is claimed to becapable of raising water availability to alevel higher than that expected fromDenver's proposed Two Forks Dam andReservoir.

The U.S. Congress approved a nation­al charter for the National Mining Hallof Fame and Museum in Leadville, whichwill become a repository of mining arti­facts and serve the industry in educatingthe public about mining.

Nevada

Nevada's nonfuel mineral productionwas estimated to be valued at $1.87 bil­lion in 1988, an increase of $420 millionfrom 1987. The increase resulted from a33-percent rise in gold production to 3.6million troy ounces and a 35-percent risein silver production to 16.5 million troyounces. Nevada was the leading State inthe Nation in the production of barite,

gold, mercury, and silver and was thesole producer of mined magnesite. In1988, Nevada ranked third in the UnitedStates in value of nonfuel mineral pro-duction. _

Precious-metal production continued.to increase with at least 10 additionalmine openings. Extensive explorationfor precious metals continued throughoutNevada, focusing on deeper deposits inthe Carlin Trend area in the northwest-ern part of the State. Drilling andexploration projects were conducted inevery county, with important discoveriesreported in Elko, Eureka, Humboldt,Mineral, Nye, and White Pine Counties.

Byproduct production from severalnorthern Nevada gold and silver mineswas a major source of mercury. Nevadafurnished almost all of the Nation'smercury output. The State's barite pro­duction continued to decline, with 1988output estimated at 293,000 short tons,Spercent lower than in 1987. Value alsodeclined to $4.2 million, or 12 percentlower than in 1987. Despite the drop inproduction, Nevada remained the leadingbarite-producing State in the Nation.

At the end of August 1988, the U.S.Bureau of Land Management reportedthat 45,948 mining claims had beenreceived in the Nevada office. Employ­ment in the Nevada mining industryreached 11,000 by October 1988, com­pared to 8,700 in October 1987. By ..Ayearend, the industry had added 2,400~jobs statewide, a 28.2-percent increase.

New Mexico

The value of nonfuel mineral produc­tion in New Mexico in 1988 was esti­mated at a record high of $1.01 billion,a 37-percent increase over 1987. Metalsoutput accounted for more than two­thirds of the total value of the State'snonfuel mineral production, with copperbeing the principal contributor.

The State's leading commodities in­cluded copper, potash, construction sandand gravel, portland cement, silver, gold,perlite, and crushed stone. Nationally,New Mexico ranked first in productionof perlite and potassium salts and secondin copper, mica, pumice, and silver. In­creases were posted for portland cement,copper, gold, lead, perlite, potassiumsalts, pumice, and silver.

The chief reason for the rise in thevalue of nonfuel mineral production wasthe 48-percent increase in the value ofcopper due to higher prices. In contrast,the quantity of copper produced roseonly 2 percent. Another factor in therise in production value was the more ..than 50-percent increase in the quantity .,and value of gold output. Gold prices

(continued on page 12)

Arizona Geology, vol. 19, no. 2, Summer 1989

p

Theses and Dissertations, 1988

(continued on page 12)

fixations: M.S. professional paper, 61p. (RNR)

Elder, A.N., Neutron gauge calibrationmodel for water content of geologicdata: M.S. thesis. (HWR)

Fabryka-Martin, J.T., Production of radi­onuclides in the earth and their hy­drogeologic significance with emphasison chlorine-36 and iodine-129: Ph.D.dissertation, 399 p. (HWR)

Feldman, P.R, Hydrogeology of a con­taminated industrial site on filled land:M.S. thesis, 127 p. (HWR)

Goering, T.J., Use of gamma-ray geoto­mography to measure dry bulk densityand unsaturated flow through tuff:M.S. thesis. (HWR)

Haldeman, W.R, Water flow through var­iably saturated fractured tuff: A labo­ratory study: M.S. thesis. (HWR)

Hanson, RT., Aquifer-system compaction,Tucson basin and Avra Valley, Arizo­na: M.S. thesis. (HWR)

Hartshorne, P.M., Paleoenvironmentalanalysis of a coral-rudist bioherm;Upper Mural Limestone (Lower Creta­ceous), southeast Arizona: M.S. pre­publication manuscript, 58 p. (G)

Hazlehurst, W.M., An estimation of thewater resources for water planningand management in Fort Valley, Coco­nino County, Arizona: M.S. thesis, 138p. (HWR)

Jeon, G.J., Innovative methods for long­term mineral forecasting: Ph.D. disser­tation, 299 p. (MGE)

Karnieli, Arnon, Storm runoff forecastingmodel incorporating spatial data: PhD.dissertation, 249 p. (RNR)

Kebler, D.G., Coagulation of submicronaluminum hydroxide colloids by silicaparticles: M.S. thesis, 198 p. (HWR)

Lapham, W.W., Conductive and convec­tive heat transfer in sediments nearstreams: Ph.D. dissertation, 318 p.(HWR)

Law, KJ., Dissolution of lead smelterdust compounds by humic acid: M.S.thesis, 30 p. (G)

Lawson, P.W., Sorption of fulvic acid onaluminum oxide and desert soil: M.S.thesis. (HWR)

Leo, T.P., Computer studies of heattracer experiments in fractured rock:M.S. thesis. (HWR)

MacInnes, S.c., Lateral effects in con­trolled source < audiomagnetotelurics:Ph.D. dissertation, 188 p. (G)

Maus, D.A., Ore controls at the GoldenRule mine, Cochise County, Arizona:M.S. thesis, 114 p. (G)

Page, D.I., Overland flow partitioning forrill and interrill erosion modeling: M.S.

perspective ofwind regimes, and

Muehlberger, E.W., The structure andgeneral stratigraphy of the westernhalf of the Payson basin, Gila County,Arizona: M.S. thesis, 86 p.

Shirley, DH., Geochemical facies analysisof the Surprise Canyon Formation inFern Glen channelway, central GrandCanyon, Arizona: M.S. thesis, 240 p.

Waters, J.P., A geophysical and geochem­ical investigation of selected collapsefeatures on the Coconino Plateau innorthern Arizona: M.S. thesis, 112 p.

University of Arizona

Akman, H.H., Resistivity and induced po­larization responses over two differentearth geometries: M.S. thesis, 109 p.(G)

Asmerom, Yemane, Mesozoic igneous ac­tivity in the southern Cordillera ofNorth America; implication for tecton­ics and magma genesis: Ph.D. disser­tation, 232 p. (G)

Aubele, Jane, Crumpeler, J.S., andElston, W.E., Vesicle zonation and ver­tical structure of basalt flows: M.S.thesis, 59 p. (PS)

Beer, KE., A ground-water study andpredictive model for the town of Flor­ence, Arizona: M.S. thesis, 105 p.(HWR)

Brooks, S.J., A multidisciplinary analysisof the hydrogeology of the MaricopaSuperconducting Super Collider (SSC)site, Maricopa County, Arizona: M.S.thesis, 85 p. (HWR)

Byrne, RW., Ridge-transform-ride dy­namics: M.S. prepublication manuscript,23 p. (G)

Calderone, G.J., Paleomagnetism of Mio­cene volcanic rocks in the Mojave­Sonora Desert region, Arizona andCalifornia: Ph.D. dissertation, 163 p.(G)

Chen, Chuangming, Andisols of the SanFrancisco volcanic field, Arizona: M.S.thesis, 111 p. (SWS)

Chuang, Yuen, Solute transport measure­ment by ion-selective electrodes infractured tuff: M.S. thesis. (HWR)

Identification of an op­grc:Julld1water management strate­

contaminated aquifer: M.S.

DClle~~ovl'skj, J.R., The hydrogeochemistryin the Ranegras Plain

gI'()til1ld\'lrah~rbasin: M.S. thesis. (HWR)Paleomagnetim of the

Implications forAmerican apparentM.S. prepublication

Northern Arizona Urliv1ersity

Darrach, M.E., A kinematic and l1:el:Jmlet­ric structural analysis on anProterozoic crustal-scale shearthe evolution of the Shylockzone, central Arizona: M.S.78p.

Johns, M.E., Architectural element,_ sis and depositional history• Upper Petrified Forest Member

Chinle Formation, PetrifiedNational Park, Arizona: M.S.163 p.

Doorn, S.S., Theoretical energetics ofthe formation of iron-nickel alloyand magnetite in olivine: M.S. thesis,116 p. (Gl)

Evans, KE., Distribution of hourly rain­fall intensities in the southwest UnitedStates summer monsoon: M.A. thesis,80 p. (Gg)

Schuver, H.J., Modeling volcano morphol­ogy: M.S. thesis, 120 p. (Gl)

Arizona State University

Arizona State University, Tempe, AZ85287; (602) 965-9011. (Gg-Geography;GI-Geology)

Northern Arizona University, Flagstaff,AZ 86011; (602) 523-9011.

eJniVerSity of Arizona, Tucson, AZ 85721;(602) 621-2211. (G-Geosciences; HWR­Hydrology and Water Resources; MGE­Mining and Geological Engineering;PS-Planetary Sciences; RNR-RenewableNatural Resources; SWS-Soil and WaterScience)

e The following list includes theses anddissertations on Arizona geology, geolog­ical engineering, hydrology, and relatedsubjects that were awarded in 1988 byArizona State University, Northern Ari­zona University, and the University ofArizona. This list, however, is not acomplete compilation of theses on suchtopics. Theses on the geology of otherStates that were awarded by these uni­versities are not listed, nor are theseson the geology of Arizona that wereawarded by out-of-State universities.

Most theses included here are notavailable in the library of the ArizonaGeological Survey. Each thesis, however,may be examined at the main library ofthe university that awarded it. Informa­tion may also be obtained from therespective departments, which are indi­cated in parentheses after each citationusing the codes listed below. (Thesesfrom Northern Arizona University wereawarded by the geology department.)

Arizona Geology, vol. 19, no. 2, 5

Figure 2 (right). Simplified geologic map ofthe Buckskin and Rawhide Mountains show­ing the location of important mines and geo­graphic features.· The Buckskin Mountainsinclude all areas of bedrock south of the BillWilliams River and east of the ColoradoRiver, unless otherwise labeled (modified fromSpencer, 1989).

(continued from page 1)

for other areas in western North Ameri­ca, Spain, and New Guinea. The recentlydiscovered Copperstone mine, Arizona'slargest gold producer with annual pro­duction at approximately 60,000 ounces,is now known to be a detachment-fault­related deposit (Spencer and others,1988). Recent recognition of thesedeposits as a distinct deposit type andtheir association with metamorphic corecomplexes, which are themselves recentlyrecognized and incompletely understoodfeatures, have sparked much scientificinterest. Discovery of the Copperstonemine has also generated explorationinterest in these deposits. The largestdomestic deposits of manganese, a stra­tegic and critical mineral, are present inthe Artillery Mountains, which are adja­cent to the Buckskin and RawhideMountains, and may have originated byprocesses associated with detachmentfaulting. Because of these geologic andmineral-resource attributes, the Buckskinand Rawhide Mountains have attractedconsiderable attention from geologistsduring the past 15 years, beginning withthe pioneering PhD. study of the geolo­gy of the Rawhide Mountains by TerryShackelford (Shackelford, 1976, 1989a,b;Davis, G.A., 1989).

+

LOWER-PLATE UNITS

MYLONITIC CRYSTALLINE ROCKS (TERTIARY TO PROTEROZOIC)

CACTUS

11

i

114° 00'

eHarcuvar metamorphic core complex,which includes the Buckskin and Raw­hide Mountains, is one of the approx-

5

5

P L A I N

l:o':o:~o;:::1 SEDIMENTARY ROCKS (MIDDLE TO LATE MIOCENE)

POSTDETACHMENT DEPOSITS

C=:J SURFICIAL DEPOSITS (QUATERNARY TO LATEST TERTIARY)

~ BASALT AND LOCAL INTERMEDIATE TO SILICIC VOLCANIC ROCKS AND SEDIMENTARY~ ROCKS, FLAT-LYING TO GENTLY TILTED (MIDDLE TO LATE MIOCENE)

I~ MYLONITIC METASEDIMENTARY ROCKS (MESOZOIC TO PALEOZOIC)

!!2° Mi. 0! I

L34°00'

km 0

.variably mylonitic f~twall rocks alonglarge-displacement, Tertiary low-anglenormal faults (detachment faults). The

The Buckskin and Rawhide Mountainsare within the Basin and Range physio­graphic province of southwestern NorthAmerica. This province, which includessouthern and western Arizona, is charac­terized by numerous mountain rangesand intervening Cenozoic basins. Thephysiography of the Basin and RangeProvince is largely the product of middleand late Cenozoic low- and high-anglenormal faulting, volcanism, and erosion.The significance and'l'elative age of eachof these processes vary greatly fromrange to range. Miocene low-angle nor­mal faulting was the dominant processthat determined the physiography of theBuckskin and Rawhide Mountains. Youn­ger basaltic volcanism, erosion, andminor, postdetachment high-angle fault­ing were also important.

Cordilleran metamorphic core com­plexes are typically characterized bynormal-faulted and extended hanging­wall rocks that overlie well-lineated,

Geology

6 Arizona Geology, vol. 19, no. 2, Summer 1989

0'·

l~+ -r "

8 U T L E R V A L L E Y

core complexes have been intensivelystudied during the Pilst 15 years. Theseonce enigmatic associations of rocks andstructures are now generally recognized

UPPER-PLATE UNITS

SEDIMENTARY AND VOLCANIC ROCKS, GENERALLYMODERATELY TO STEEPLY DIPPING (LATEOLIGOCENE TO MIDDLE MIOCENE)

METAVOLCANIC AND METASEDIMENTARY ROCKS(MESOZOIC)

METASEDIMENTARY ROCKS (PALEOZOIC)

CRYSTALLINE ROCKS (LARGELY PROTEROZOIC,LOCALLY TERTIARY AND MESOZOIC)

\&ately 10 such complexes that are dis­continuously exposed in a belt extendingdiagonally across Arizona into southeast­ern California (Figure 1). Metamorphic

Arizona Geology, vol. 19, no. 2, Summer 1989

..Jl.-Il- ,"

J.--l.- ...

..J-...

--'"...........

SYMBOLS

BUCKSKIN-RAWHIDE DETACHMENT FAULT

LOW-ANGLE NORMAL FAULT

HIGH-ANGLE NORMAL FAULT

HIGH-ANGLE FAULT

THRUST OR REVERSE FAULT

ALL FAULTS DASHED WHERE APPROXIMATELYLOCATED OR INFERRED, DOTTED WHERE CONCEALED.

as products of large-magnitude displace­ment on moderately to gently dippingnormal faults and their down-dip contin­uations as ductile shear zones.

7

Figure 3. Schematic structure-stratigraphy diagram for the Buckskin and, Rawhide Mountainsshowing all important pre-Pliocene rock types and some of their contact relationships.Movement on rotational normal faults (not shown) caused tilting of upper-plate rocks.

Mineralization and Alteration

Mineral deposits are widely distrib­uted in the Buckskin and Rawhide Moun­tains and, with a few notable exceptions,are along or within a few tens of metersof the detachment fault (Figure 6).Most of the depositS contain massive orfracture-filling specular hematite andyounger fracture-filling chrysocolla.Early-formed copper and iron sulfideswere probably common, but are largelyobscured by later oxidation. Hydrother­mal-carbonate replacements are alsopresent along the fault and are common-ly associated with copper-iron mineraldeposits. These deposits have yieldedapproximately 52 million pounds of cop­per and 15,500 ounces of gold, withminor amounts of lead, zinc, and silver(Keith and others, 1983). All of the'.'deposits formed at the same time tha:detachment faulting and related struc­tural and sedimentary phenomenaoccurred. They are believed to have

from beneath a wedge of brittlelyextending upper-plate rocks, and wereoverprinted successively by chloriticalteration and brecciation, microbreccJ'ia­tion, and fault-gouge formation along .narrow fault zone (Wernicke, 1981, 19 ;Davis, G.B., 1983; Reynolds, 1985; Davis,G.A., and others, 1986). Arching andsubareal exposure of the lower plate ledto shedding of mylonitic debris into syn­tectonic sedimentary basins and to thedistinctive physiography of many of thecomplexes (Rehrig and Reynolds, 1980;Howard and others, 1982; Spencer, 1984;Pain, 1985; Miller and John, 1988; Spen­cer and others, 1989a).

Upper-plate rocks in the Buckskinand Rawhide Mountains contain abun­dant evidence of compressional deforma­tion and metamorphism of Mesozoic andPaleozoic sedimentary rocks. The stra­tigraphy of the pre-Tertiary rocks isrecognizable in spite of variable buttypically severe deformation and green­schist-grade metamorphism (Reynoldsand others, 1987, 1989; Reynolds andSpencer, 1989; Spencer and others,1989b). Deformation occurred in associ­ation with generally south-directed, lateMesozoic thrust faulting within the east­west-trending Maria fold-and-thrust belt(Reynolds and others, 1986).

Detachment faulting and relateddeformation and sedimentation were fO~.1

lowed by dominantly basaltic volcanis~

with local associated felsic volcanism .(Suneson and Lucchitta, 1983). Trachyteflows and interbedded pyroclastic rocksin the western Buckskin Mountains arethe same age as, and may have evolvedfrom, magmas associated with adjacentpostdetachment basalts (Grubensky,1989).

(Davis, G.A., and others, 1986; Davis,G.A., and Lister, 1988; Marshak andVander Muelen, 1989; Spencer and Rey­nolds,1989b).

The detachment fault forms a corru­gated surface defined by east-north­east-trending antiforms and synforms(Figure 4). Lower-plate foliation andlithologic layering broadly conform tothe form of the detachment fault, atleast in areas where exposure throughthe lower plate is good, such as theeast face of Planet Peak and the westface of Ives Peak (Figure 2). The originof these corrugations is unknown, butthey are suspected to be related todetachment faulting and mylonitizationbecause the direction of displacement onthe detachment fault and mylonitic lin­eation are approximately parallel to anti­form and synform axes.

Except for the corrugations, all ofthe basic Tertiary structural features inthe Buckskin and Rawhide Mountains,and in metamophic core complexes ingeneral, are accounted for by the shear­zone model. This model envisions thateach metamorphic core complex originat­ed by large displacement on a masterlow-angle normal fault that extendeddown dip into a zone of mylonitization(Figure 5). According to this model,rocks originally mylonitized at perhaps8- to IS-kilometer depth rose isostati­cally and cooled as they were displaced

THRUST FAULT

REPLACEMENT CARBONATE

CHLORITIC BRECCIA

CARBONATE AND CALC-Sill CATESLIVER

"""f---VARIABLY MYLONITIC CRYSTALUNEROCKS

The subhorizontal Buckskin-Rawhidedetachment fault is exposed discontinu­ously throughout the Buckskin andRawhide Mountains (Figure 2). Hanging­wall rocks, collectively referred to asthe upper plate, consist of a variety ofcomplexly normal-faulted and tiltedrocks that include syntectonic, mid­Tertiary sedimentary and volcanic rocksand variably deformed and metamor­phosed, Mesozoic and Paleozoic sedimen­tary and volcanic rocks (Figure 3). Thefootwall block, commonly referred to asthe lower plate (platelike form is notimplied), is composed of variably mylon­itic crystalline and metasedimentaryrocks and is thought to be structurallycontinuous with similar lower-plate rocksin the nearby Harcuvar and WhippleMountains. The mid-Tertiary age ofsome of the mylonitized rocks in theWhipple, Buckskin, and Rawhide Moun­tains has recently been established byU-Ph (zircon) geochronologic study(Wright and others, 1986; Bryant andWooden, 1989). A northeastward direc­tion of displacement of upper-plate rocksrelative to the lower plate is inferredbased on a number of criteria (e.g.,Davis, G.A., and others, 1980; Reynoldsand Spencer, 1985; Howard and John,1987). The sense of displacement on thedetachment fault is the same as thatindicated for mylonitization by asym­metric petrofabrics in the mylonites

Arizona Geology, vol. 19, no. 2, Summer 1989

N ]

134°00'

KM 0 5 10 15 20I I !

I 'I 'i I

MI 0 5 \0

113°30' o QUATERNARY SURFICIAL DEPOSITS

UPPER-PLATE ROCKS

LOWER-PLATE ROCKS, WITHCONTOURS SHOWING MINIMUMELEVATION OF DETACHMENTFAULT IN METERS

HIGH-ANGLE FAULT,DASHED WHERE APPROXIMATE ORINFERRED, DOTTED WHERECONCEALED

Figure 4 (above). Minimum-relief contour map of the Buckskin-Rawhide detachment fault.

9

formed from aqueous brines that leachedmetals from strata within extensionalsedimentary basins (Wilkins and Heid­rick, 1982; Spencer and Welty, 1986,1989; Wilkins and others, 1986; Lehmanand Spencer, 1989). The recent discov­ery of the Copperstone deposit in west­central Arizona, which is estimated tocontain more than 500,000 ounces ofgold and is related to the Moon Moun­tains detachment fault, has led torenewed interest in detachment-fault­related mineral deposits (Spencer andothers, 1988).

Manganese deposits hosted in upper­plate, Miocene sedimentary rocks in theBuckskin and Rawhide Mountains haveyielded approximately 24 million poundsof manganese. Similar manganese depos­its in the nearby Artillery Mountains arethe largest of such deposits in theUnited States (Lasky and Webber, 1949).Some of the deposits in the ArtilleryMountains are younger than previouslysuspected and may postdate detachmentfaulting and related mid-Tertiary tecto­nism. These younger deposits formedfrom low-salinity fluids and thus werenot derived directly from the salineaqueous fluids that caused detachment­fault-related mineralization (Spencer andothers, 1989a).

Figure 5 (left), Cross-section evolution dia­gram of Miocene extension in the Buckskinand Rawhide Mountains.

10090o7060o KM

~BREAKAWAY5

15

B 10

Arizona Geology, vol. 19, no. 2,

BREAKAWAY

A : -l:1ik>-·.·.. ::J::,::~;:,~'i·:,~·;f3)~·,~i;.;::.:·;;,,~:.:..;;:··;;,,· ~~I:NC:,P:1E~NT~M~'~CO~N:1T1Z:'T:,O~~;~;~~~~~~·

-D

Conclusion

Selected References

Rawhide Mountains present an excep­tional opportunity to improve basicgeologic understanding.

Although Bulletin 198 represents amajor step forward in deciphering thltcomplex geologic evolution of a majorCordilleran metamorphic core complex, itis clear that many questions remain un­answered. One can only hope that futureinvestigators find these problems inter­esting and tractable and that the mo­mentum established since Terry Shackel­ford's pivitol dissertation will continueto advance the geologic understanding ofthis remarkable area.

Brooks, W.E., 1986, Distribution of anomalouslyhigh K20 volcanic rocks in Arizona: Meta­somatism at the Picacho Peak detachmentfault: Geology, v. 14, p. 339-342.

__ 1988, Recognition and geologic implicationsof potassium metasomatism in upper-platevolcanic rocks at the detachment fault at theHarcuvar Mountains, Yavapai County, Arizo­na: U.S. Geological Survey Open-File Report88-17,9 p.

Bryant, Bruce, and Wooden, J.1., 1989, Lower­plate rocks of the Buckskin Mountains, Arizo­na: A progress report, in Spencer, J.E., andReynolds, S.J., eds., Geology and mineralresources of the Buckskin and Rawhide Moun­tains, west-cen tral Arizona: Arizona Geologi­cal Survey Bulletin 198, p. 47-50.

Davis, G.A., 1989, Terry Shackelford and the Raw-hide Mountains: A retrospective view, inSpencer, J.E., and Reynolds, S.J., eds., Geoi.ogy and mineral resources of the BuckskiIllllJand Rawhide Mountains, west-central Arizo-na: Arizona Geological Survey Bulletin 198,p.11-14.

Davis, G.A., Anderson, J.1., Frost, E.G., andShackelford, T.J., 1980, Mylonitization anddetachment faulting in the Whipple-Buckskin­Rawhide Mountains terrane, southeasternCalifornia and western Arizona, in Crittenden,M.D., Jr., and others, eds., Cordilleran meta­morphic core complexes: Geological Societyof America Memoir 153, p. 79-129.

Davis, G.A., and Lister, G.S., 1988, Detachmentfaulting in continental extension; perspectivesfrom the southwestern U.S. Cordillera, inClark, S.P., Jr., and others, eds., Processes incontinental lithospheric deformation: Geologi­cal Society of America Special Paper 218, p.133-160.

Davis, G.A., Lister, G.S., and Reynolds, S.J., 1986,Structural evolution of the Whipple and SouthMountains shear zones, southwestern UnitedStates: Geology, v. 14, p. 7-10.

Davis, G.H., 1983, Shear-zone model for the originof metamorphic core complexes: Geology, v.11, p. 342-347.

Grubensky, M.J., 1989, Geology of postdetach­ment, Miocene volcanic rocks in the south­western Buckskin Mountains, in Spencer, J.E.,and Reynolds, S.J., eds., Geology and mineralresources of the Buckskin and Rawhide Moun­tains, west-cen tral Arizona: Arizona Geologi­cal Survey Bulletin 198, p. 255-262.

Halfkenny, R.D., Jr., Kerrich, Robert, and Rehrig,W.A., 1989, Fluid regimes and geochemicalmass transport in the development of mylon-ites and chloritic breccias at Copper Penney,Buckskin Mountains, in Spencer, J.E., andReynolds, S.J., eds., Geology and mineral rl'.sources of the Buckskin and Rawhide Moun'Wtains, west-central Arizona: Arizona Geo­logical Survey Bulletin 198, p. 190-202.

Howard, K.A., and John, B.E., 1987, Crustal exten­sion along a rooted system of imbricate low-

BASALT

SANDSTONE AND CONGLOMERATE

VOLCANIC FLOWS AND TUFFS

LIMESTONE/MARBLE

SEDIMENTARY BRECCIA

HYDROTHERMAL CARBONATE

GRANITIC ROCKS

CHLORITIC BRECCIA

MYLONITIC CRYSTALLINE ROCKS

~.+.....I + + + ~

f777'~II;r/ 1,!I\j~

IA ",AA All LI ill

...!,:,c::,':/

Figure 6. Sites of mineralization dur­ing detachment faulting.

Better understanding of the genesisof metamorphic core complexes, theirrelationship to older tectonic features,and their associated mineral deposits andigneous rocks could elucidate the natureof general processes that occur inextensional tectonic settings, includingthose related to the genesis of economicmineral deposits. The remarkably well­exposed and well-developed compres­sional and extensional structures andmineral deposits in the Buckskin and

calcite and iron-manganese-oxide veinemplacement (Reynolds and Lister, 1987;Halfkenny and others, 1989).

The abundant evidence for wide­spread mid-Tertiary mineralization andalteration suggests that complex chemicaland physical processes operated on ascale at least as large as the metamor­phic core complex itelf. Genetic rela­tionships between copper + iron ± goldmineralization and carbonate metasoma­tism along detachment faults, and Kmetasomatism and manganese minerali­zation in the upper plate, have not beenestablished. All, however, were producedapproximately synchronously in the sametectonic environment and are remarkablywell developed in the Buckskin andRawhide Mountains.

Figure 7. Setting and types ofmineralization and alteration during extension.

In addition to manganese and de­tachment-fault-related mineralization,widespread potassium metasomatism ofupper-plate rocks and chloritic alterationof brecciated rocks below the detach­ment fault attest to the pervasiveness ofaqueous geochemical activity duringdetachment faulting (Figure 7). K meta­somatism has been recognized elsewherein association with detachment faults(Brooks, 1986, 1988) and is known to beolder than detachment-fault-relatedmineralization in the eastern HarcuvarMountains (Roddy and others, 1988). Kmetasomatism in the Buckskin Mountainshas largely converted mafic volcanicflows, which may have originally beenalkalic, to K-feldspar, calcite, and ironand manganese oxides (Kerrich andothers, 1989). Plagioclase in K-metaso­matized, upper-plate basalt flows in theBuckskin Mountains has been largely orentirely converted to K-feldspar; numer­ous K-Ar dates of feldspar concentratesfrom these rocks reveal a mid-Mioceneage of K metasomatism (Spencer andothers, 1989c). Chloritic alteration oflower-plate rocks, involving massiveaddition of iron, manganese, and magne­sium and loss of silica, sodium, andpotassium, occurred in a different fluidregime than that associated with later

Arizona Geology, vol. 19, no. 2, Summer 1989

angle faults: Colorado River extensional cor­ridor, California and Arizona, in Coward, M.P., and others, eds., Continental extensionaltectonics: GeQlogical Society of London Spe­cial Publication 28, p. 299-311.

~10ward, K.A., Stone, Paul, Pernokas, M.A., and'WI' Marvin, RF., 1982, Geologic and geochrono­

logic reconnaissance of the Turtle Mountainsarea, California, west border of the WhippleMountains detachment terrane, in Frost, E.G.,and Martin, D.L., eds., Mesozoic-Cenozoic tec­tonic evolution of the Colorado River region,California, Arizona, and Nevada: San Diego,Cordilleran Publishers, p. 341-354.

Keith, S.B., Gest, D.E., DeWitt, Ed, Woode Toll,Netta, and Everson, B.A., 1983, Metallic min­eral districts and production in Arizona:Arizona Bureau of Geology and Mineral Tech­nology Bulletin 194,58 p.

Kerrich, Robert, Rehrig, W.A., and McLarty, Elisa­beth, 1989, Volcanic rocks in the suprastructureof metamorphic core complexes, southwestArizona: Geochemical and isotopic evidencefor primary magma types and secondaryhydrothermal regimes, in Spencer, J.E., andReynolds, S.J., eds., Geology and mineralresources of the Buckskin and Rawhide Moun­tains, west-central Arizona: Arizona Geologi­cal Survey Bulletin 198, p. 203-214.

Lasky, S.G., and Webber, B.N., 1949, Manganeseresources of the Artillery Mountains region,Mohave County, Arizona: U.S. GeologicalSurvey Bulletin 961, 86 p.

Lehman, N.E., and Spencer, J.E., 1989, Mineraliza­tion in the central part of the Planet mineraldistrict, northwestern Buckskin Mountains, inSpencer, J.E., and Reynolds, S.J., eds., Geologyand mineral resources of the Buckskin andRawhide Mountains, west-central Arizona:Arizona Geological Survey Bulletin 198, p. 215­222.

Marshak, Stephen, and Vander Meulen, Marc,1989, Geology of the Battleship Peak area,a southern Buckskin Mountains, Arizona: Struc­

.. fturall ~tyle belowJ

Ethe Bduckskin detachmentau t, In Spencer, .., an Reynolds, S.J., eds.,

Geology and mineral resources of the Buck­skin and Rawhide Mountains, west-centralArizona: Arizona Geological Survey Bulletin198, p. 51-66.

Miller, J.M.G., and John, RE., 1988, Detachedstrata in a Tertiary low-angle normal faultterrane, southeastern California: A sedimen­tary record of unroofing, breaching, arid con­tinued slip: Geology, v. 16, p. 645-648.

Pain, e.F., 1985, Cordilleran metamorphicicor~

complexes in Arizona: A contribution fromgeomorphology: Geology, v. 13, p. 871-874.

Rehrig, W.A., and Reynolds, S.J., 1980, Geologicand geochronologic reconnaissance of a n()~th­

west-trending zone of metamorphic core.c0Ilt-.plexes in southern and western Arizona,inCrittenden, M.D., Jr., and others, eds.,Co~­

dilleran metamorphic core complexes: Geolog­ical Society of America Memoir 153, p.131-157.

Reynolds, S.J., 1980, A conceptual basisfortlt~

occurrence of uranium in Cordilleran meta"morphic core complexes, in Coney, P.J.,/aI\d.Reynolds, S.J., eds., Cordilleran metarllOrphiccore complexes and their uranium favor~bilit}',

with contributions by G.H. Davis and0tl\~rs:

gj~x?~~~~';\~~_~l;;~rgy open-Filei~eI"'rt__ 1985, Geology of the South Mountaills,cell"

~~~:c~z~~ca~n~~;yn~J~~:~9~: ~e;J°g}'S~i0Reynolds, S.J., and Lister, G.S., 1987,Stnlct11Tal

:~:~~o:;s:fl~~~O;;' :~~:;.t~~~~.dE!t~c0·Reynolds, S.J., and Spencer, J.E., 1985, EVi~e

for large-scale transport on the Bullar~d~t~clt"

at ~~;~ ~fis~est-centralArizona: GeOl~g}'!8"

~ 1989, Pre-Tertiary rocks and struc.t11Tes:illthe upper plate of the Buckskin detaslt.Iltl!lltfault, west-central Arizona, in Spencer~l.·and Reynolds, S.J., eds., Geology andl1un~

resources of the Buckskin and RawhideMo

Arizona Geology, vol. 19, no. 2, Summer 198~

tains, west-central Arizona: Arizona Geologi­cal Survey Bulletin 198, p. 67-102.

Reynolds, S.J., Spencer, J.E., Asmerom, Yemane,DeWitt, Ed, and Laubach, S.E., 1989, EarlyMesozoic uplift in west-central Arizona andsoutheastern California: Geology, v. 17, p.207-211.

Reynolds, S.J., Spencer, J.E., and DeWitt, Ed, 1987,Stratigraphy and U-Th-Pb geochronology ofTriassic and Jurassic rocks in west-central Ari­zona, in Dickinson, W.R, and Klute, M.A.,eds., Mesozoic rocks of southern Arizona andadjacent areas: Arizona Geological SocietyDigest, v. 18, p. 65-80.

Reynolds, S.J., Spencer, J.E., Richard, S.M., andLaubach, S.E., 1986, Mesozoic structures inwest-central Arizona, in Beatty, Barbara, andWilkinson, P.A.K., eds., Frontiers in geologyand ore deposits of Arizona and the South­west: Arizona Geological Society Digest, v. 16,p.35-51.

Roddy, M.S., Reynolds, S.J., Smith, RM., andRuiz, Joaquin, 1988, K-metasomatism anddetachment-related mineralization, HarcuvarMountains, Arizona: Geological Society ofAmerica Bulletin, v. 100, p. 1627-1639.

Shackelford, T.J., 1976, Structural geology of theRawhide Mountains, Mohave County, Arizo­na: Los Angeles, University of Southern Cali­fornia, unpublished Ph.D. dissertation, 176 p.

1989a, Geologic map of the Rawhide Moun­tains, Mohave County, Arizona, in Spencer, J.E., and Reynolds, S.J., eds., Geology and min­eral resources of the Buckskin and RawhideMountains, west-central Arizona: ArizonaGeological Survey Bulletin 198, scale 1:42,850.

1989b, Structural geology of the RawhideMountains, Mohave County, Arizona, in Spen­cer, J.E., and Reynolds, S.J., eds., Geology andmineral resources of the Buckskin and Raw­hide Mountains, west-central Arizona: Arizo­na Geological Survey Bulletin 198, p. 15-46.

Spencer, J.E., 1984, Role of tectonic denudation inwarping and uplift of low-angle normal faults:Geology, v. 12, p. 95-98.

1989, Compilation geologic map of the Buck­. and Rawhide Mountains, west-centralrizona, in Spencer, J.E., and Reynolds,S.].,

eds., Geology and mineral resources of theBuckskin and Rawhide Mountains, west-entral Arizona: Arizona Geological Survey

letin 198; scale 1:100,000.J.E., Duncan, J.T., and Burton, W.D.,he Copperstone mine: Arizona's new

gold producer: Arizona Bureau of Geologyand Mineral Technology Fieldnotes, v. 18, no.2, p. 1-3.

Spencer, J.E., Grubensky, M.J., Duncan, J.T.,Shenk, J.D., Yamold, J.e., and Lombard, J.P.,1989a, Geology and mineral deposits of thecentral Artillery Mountains, in Spencer, J.E.,and Reynolds, S.J., eds., Geology and mineralresources of the Buckskin and Rawhide Moun­tains, west-central Arizona: Arizona Geologi­cal Survey Bulletin 198, p. 168-183.

Spencer, J.E., and Reynolds, S.J., 1989a, Introduc­tion to the geology and mineral resourcesof the Buckskin and Rawhide Mountains,in Spencer, J.E., and Reynolds, S.J., eds., Geol­ogy and mineral resources of the Buckskinand Rawhide Mountains, west-central Arizo­na: Arizona Geological Survey Bulletin 198, p.1-10.

__ 1989b, Tertiary structure, stratigraphy, andtectonics of the Buckskin Mountains, in Spen­cer, J.E., and Reynolds, S.J., eds., Geology andmineral resources of the Buckskin and Raw­hide Mountains, west-central Arizona: ArizonaGeological Survey Bulletin 198, p. 103-167.

Spencer, J.E., Reynolds, S.J., and Lehman, N.E.,1989b, Geologic map of the Planet-Mineral Hillarea, northwestern Buckskin Mountains, west­central Arizona, in Spencer, J.E., and Reynolds,S.J., eds., Geology and mineral resources of theBuckskin and Rawhide Mountains, west­central Arizona: Arizona Geological SurveyBulletin 198, scale 1:24,000.

Spencer, J.E., Shafiqullah, M., Miller, RJ., andPickthorn, L.G., 1989c, K-Ar geochronology ofMiocene extension, volcanism, and potassiummetasomatism in the Buckskin and RawhideMountains, in Spencer, J.E., and Reynolds, S.J.,eds., Geology and mineral resources of theBuckskin and Rawhide Mountains, west­central Arizona: Arizona Geological SurveyBulletin 198, p. 184-189.

Spencer, J.E., and Welty, J.W., 1986, Possiblecontrols of base- and precious-metal mineral­ization associated with Tertiary detachmentfaults in the lower Colorado River trough,Arizona and California: Geology, v. 14, p.195-198.

__ 1989, Geology of mineral deposits in theBuckskin and Rawhide Mountains, in Spencer,J.E., and Reynolds, S.J., eds., Geology andmineral resources of the Buckskin and Raw­hide Mountains, west-central Arizona: Arizo­na Geological Survey Bulletin 198, p. 223-254.

Suneson, N.H., and Lucchitta, Ivo, 1983, Origin ofbimodal volcanism, southern Basin and RangeProvince, west-central Arizona: GeologicalSociety of America Bulletin, v. 94, p. 1005-1019.

Wernicke, Brian, 1981, Low-angle normal faults inthe Basin and Range Province: Nappe tecton­ics in an extending orogen: Nature, v. 291, p.645-648.

__ 1985, Uniform-sense normal simple shear ofthe continental lithosphere: Canadian Journalof Earth Sciences, v. 22, p. 108-125.

Wilkins, Joe, Jr., Beane, RE., and Heidrick, T.L.,1986, Mineralization related to detachmentfaults: A model, in Beatty, Barbara, and Wil­kinson, P.A.K., eds., Frontiers in geology andore deposits of Arizona and the Southwest:Arizona Geological Society Digest, v. 16, p.108-117.

Wilkins, Joe, Jr., and Heidrick, T.L., 1982, Baseand precious metal mineralization related tolow-angle tectonic features in the WhippleMountains, California and Buckskin Moun­tains, Arizona, in Fiost, E.G., and Martin, D.L., eds., Mesozoic-Cenozoic tectonic evolutionof the Colorado River region, California, Ari­zona, and Nevada: San Diego, CordilleranPublishers, p. 182-203.

Wright, J.E., Anderson, J.L., and Davis, G.A.,1986, Timing of plutonism, mylonitization, anddecompression in a metamorphic core com­plex, Whipple Mountains, CA [abs.]: Geo­logical Society of America Abstracts withPrograms, v. 18, p. 201.

11

(continued from page 4)

remained high, even though the averageprice slipped· from $448 per troy ouncein 1987 to an estimated $439 in 1988.Although silver production rose nearly30 percent in quantity, lower pricesbrought a slump in value. No molyb­denum production was reported in 1988.

After several years of depressedprices in the potash industry, productionstabilized and its value rose more than46 percent. New Mexico producersclaimed that dumping by Canadian pro­ducers had forced U.S. prices down,and in 1987 two companies filed an anti­dumping petition with the U.S. Interna­tional Trade Commission. Early in Janu­ary 1988, Canadian potash producersagreed to sell their product to U.S.farmers at a fair-market value and

thereby avoid a final decision by thecommission to impose heavy duties onthe industry. As a result, New Mexico'spotash industry improved throughout theyear. Although several mines changedownership, others started up and oneannounced an expansion.

Utah

The value of nonfuel mineral produc­tion in Utah in 1988 increased 41 per­cent over that of 1987 and reached arecord high of $990 million. Productionexceeded the previous record achieved in1981 when copper output peaked. Metalsaccounted for about four-fifths of thevalue of nonfuel mineral production,with copper, gold, and magnesium theprincipal contributors. Leading commod-

ities included copper, gold, magnesium,portland cement, construction sand andgravel, salt, silver, crushed stone,phosphate, and potash.

The rise in the value of nonfuel mitAeral production was directly attribut~.to high prices for copper and gold andincreased output at a recently reopenedcopper mine. Although silver output in­creased, lower prices brought a slumpin value. Molybdenum production de­clined in quantity and value as pricesand demand continued to slip. Anincrease in magnesium output also con­tributed to the rise in metal production.The declines posted for constructionmaterials such as portland cement, gyp­sum, construction sand and gravel, andcrushed stone were related, in part, to adepressed construction industry and theshutdown of several operations.

,..---- Arizona Geology---~

Arizona Geological Survey

Director & State Geologist: Larry D. FellowsEditor: Evelyn M. VandenDolderEditorial Assistant: Nancy SchmidtIllustrators: Peter F. Corrao, Sherry F. Gamer

Wayne, R.F., The effect of bank protec­tion on infiltration losses in the SantaCruz River, Arizona: M.S. thesis (HWR)

Welty, J.W., Strontium isotopic composi­tions of igneous rocks at the SanManuel-Kalamazoo porphyry copperdeposit, Pinal County, Arizona: M.s.prepublication manuscript, 27 p. (G)

Yiannakakis, A.E., Adsorption/desorp­tion of phenols on the Pima clay loamsoil: M.S. thesis, 100 p. (SWS)

Young, D.P., The history of deformatio;iia.and fluid phenomenon in the top~the Wilderness Suite, Santa CatalinaMountains, Pima County, Arizona: M.S.thesis, 144 p. (G)

(continued from page 5)

thesis, 112 p. (RNR)Porcello, J.J., Pre-development hydrologic

conditions of the Salt River IndianReservation, east Salt River Valley,central Arizona, with an emphasis onthe ground-water flow regime: M.S.thesis. (HWR)

Rasmussen, T.e., Fluid flow and solutetransport through three-dimensionalnetworks of variably saturated discretefractures: Ph.D. dissertation, 327 p.(HWR)

Reed, P.E., Jr., A variable moduli proba­bilistic constitutive model for soils:M.S. thesis, 103 p. (MGE)

Rogoff, E.B., Characterization of waterinteraction with the Apache Leap Tuff,Superior, Arizona, using stable isotopesof oxygen and hydrogen: M.S. thesis,162 p. (HWR)

Scovill, G.L., Tailing pond seepage andsulfate equilibrium in the Pima miningdistrict, Pima County, Arizona: M.S.thesis, 78 p. (HWR)

Seidemann, R.H., Gaseous transport inthe vadose zone; computer simulationsusing the discrete state compartmentmodel: M.S. thesis, 82 p. (HWR)

Smith, B.D., The distribution of radon222 in the ground water of the north­central Tucson basin and its relation­ship to the hydrogeology: M.S. thesis.(HWR)

Tidwell, V.e., Determination of theequivalent saturated hydraulic conduc­tivity of fractured rock located in thevadose zone: M.S. thesis, 135 p. (HWR)

Usunoff, E.J., Factors affecting themovement and distribution of fluoridein aquifers: Ph.D. dissertation, 365 p.(HWR)

Vidris, M.R., U.S. smelter acid sales andrevenues: The implications of adoptingEuropean acid trade and marketingpractices: M.S. thesis, 174 p. (MGE)

Vogt, G.T., Porosity, pore-size distribu­tion, and pore surface area of theApache Leap Tuff near Superior, Ari­zona, using mercury porosimetry: M.S.thesis, 130 p. (HWR)

Vol. 19, No. 2

State of Arizona:

Summer 1989

Governor Rose Mofford

Arizona Geological Survey845 N. Park Ave., #100Tucson, AZ 85719TEL: (602) 882-4795