vol. 4 earth science and mineral resources in arizona dec ... · vol. 4 no.4 earth science and...

Vol. 4 NO.4 Earth Science and Mineral Resources in Arizona Dec. 1974

INTRODUCTION

ByStanton B. Keith,

Geologist

Geology, or geoscience as it is also called, is the study of theplanet earth from its origin to the present. The subject is partscience and part history. Briefly, it involves the interpretation ofthe origin of the planet, the formation and structural arrangementof the rocks, the identity and fabric of the minerals, the physicalforces and chemical changes that have or are taking place on orwithin the earth, and the record of the development of life on theplanet. Of more immediate importance is the role of geology inthe discovery of useful mineral materials; in engineering problemsconcerning the location, planning, design, and building ofstructures in or on the earth; in the problems of water supply andresources; and in the identification of geologic hazards to human

activities and welfare from natural or man-made surfacephenomena such as floods, landslides, and earthcracks or fromsubsurface mobile forces within the earth such as earthquakes andvolcanic activity. Clearly, although we may not recognize it,geology plays an important role in our daily lives and althoughmost geologic events and processes take place too slowly to bereadily recognized, they are constantly active all around us.

The geologic record of the past and present can be read fromwhat we can see or deduce on or in the planet itself. The earth isthe primary textbook. To a large extent, the record of pastgeologic events can be interpreted by comparing old geologicfeatures to similar ones currently observed or simulated. Arizonaoffers an excellent field laboratory for such studies. Rockexposures, the leaves of the history book, range in age from earlyPrecambrian time (some 1.7 billion or more years ago) to thepresent. The Grand Canyon of the Colorado; the extensiveColorado Plateau; the volcanic structures of the Flagstaff and

Northern Arizona UniversityAerial panorama, looking north, of north-central Arizona, one of the several excellent field laboratories for geologists in the State. Flagstaff, home

of Northern Arizona University, is in the foreground with the cluster of San Francisco volcanic peaks behind. In the distance extends the ColoradoPlateau cut by canyons such as the Grand Canyon, of which the north rim shows in the upper left hand corner. It may be possible to distinguish thedim form of Navajo Mountain on the skyline just right of the center.

ARIZONA B UREA U OF MINES Dec. 1974

White Mountain areas, the Mogollon Rim country, and theperplexing pattern of mountains and valleys of the Basin andRange Province of southern Arizona, with its numerous mineralresources, continually present challenges in geologicinterpretations.

Important geologic studies have been carried out in Arizona bythe U.S. Geological Survey, the Arizona Bureau of Mines, and byother organizations and individuals as evidenced by the numerouspublications listed in various bibliographies, but many excellentcontributions to the knowledge of the geology of the State havecome from the faculty and students at Arizona's threepublic-supported universities: University of Arizona in Tucson,Arizona State University at Tempe, and Northern ArizonaUniversity at Flagstaff. The departments dealing with geology atthese institutions have taken advantage of the superb fieldlaboratory Arizona offers. Through classroom instruction andfield training, students are prepared in many branches of geologic

endeavor which, along with faculty initiative and gUi~ance, leadsto numerous research projects designed both to provlde a betterunderstanding of geologic history a~d ~roce~ses and to ~repare amen and women for service to mankmd m vanous occupatlOns. It •is an exciting challenge to students and faculty.

In order to promote a better understanding of the importantrole the geology departments are playing, the Arizona Bureau ofMines devotes this issue of FIELDNOTES to a review of theactivities of those departments. To the public in general, much ofthe geologic terminology in the following articles may beunfamiliar but it may stimulate interest in learning more aboutthe geology of the State. To those having geologic interests, thisreview will provide an insight on what investigations have beenmade or are in progress at Arizona's universities.

The Bureau is indebted to the chairmen and heads of thevarious departments at the universities for the contributions theyhave provided to make possible this issue of FIELDNOTES.

DEPARTMENT OF GEOSCIENCESCOLLEGE OF EARTH SCIENCES

UNIVERSITY OF ARIZONA

ByDr. Edgar J. McCullough Jr., Head

The Department of Geosciences is oneof the four units at the University ofArizona comprising the College of EarthSciences. The Department currently has afaculty of 29 and a staff of 12. Duringthe 1973-74 year the Department ofGeosciences provided instruction to some2610 students in 68 courses and finishedthe year with 323 majors: 16 B.A.candidates, 154 B.S. candidates, 101 M.S.candidates, 42 Ph.D. candidates, and 10unclassified or international specialstudents. Forty-seven students completedwork for degrees: 24 B.S., 17 M.S., and 6Ph.D. During this period, the facultypublished 1 book,S chapters in books. 30articles in referred journals, 1 map, 34abstracts, 2 encylopedia articles, 6reviews, and edited 5 publications.Research grants, contracts, and giftsawarded during the year totaled some$502,000. During 1973-74, facultymembers presented papers at 4international, 12 national, 15 regional,and 1 state meeting of professional andscientific organizations, as well aspresenting 33 talks to local civic groups.The Department of Geosciences hostedthe Joint Winter Mineralogical Meetingsponsored by the Mineralogical Society ofAmerica, Friends of Mineralogy, MineralMuseums Advisory Council, Tucson Gemand Mineral Society, and the Universityof Arizona.

The Department of Geosciences isorganized around the disciplines ofgeobiology, geochemistry, geology, andgeophysics. The two major areas ofteaching and research, geochronology andnon-renewable resources, involve all fourof the disciplines. The following reporton the scholarly activities of our students

Continued page 3

DEPARTMENT OF GEOLOGYARIZONA STATE UNIVERSITY

ByDr. Troy L. Pewe', Chairman

Rocks deep in the Grand Canyon, lavaflows and volcanic ash deposits on theSan Francisco Peaks, moon rocks,environmental geology mapping,geophysical probes of the deepwater-bearing sediments near Phoenix areall part of varied teaching-researchactivities of the students and faculty ofthe Geology Department of Arizona StateUniversity. Geology was founded as aseparate department at A.S.U. in 1957and is one of the younger departments inthe 89-year-old institution known asArizona State University. TheDe p artment is now an activeresearch-oriented department offeringB.A., B.S., M.S., and Ph.D. degrees, aswell as a Departmental teaching majorand minor in the B.A. in the EducationDegree Curriculum.

The faculty consists of 12 nationallyand internationally known scholars. Allof the faculty have studied widely andalmost all have had valuable geologicexperience in various parts of the worldand are applying techniques from othercountries to better understand and usethe geology of Arizona.

The research-oriented teachers andvisiting professors work closely withgraduate and undergraduate students. Inaddition to faculty research in geologicproblems of Arizona, most of the morethan 50 graduate students on the M.S.and Ph.D. level are guided by faculty inresearch problems throughout the State.Funds for faculty and graduate studentresearch are received from NSF, NASA,U.S. Army-Durham, U.S. Army-CRREL,National Academy of Sciences, NationalP ark Service, Research Corporation,Petroleum Research Fund, U.S.Geological Survey, as well as several

Continued page 5

DEPARTMENT OF GEOLOGYNORTHERN ARIZONA UNIVERSITY

ByDr. Augustus S. Cotera Jr., Chariman

Geology at Northern ArizonaUniversity consists of both teaching andresearch with the latter being used tosupplement and compliment goodteaching. Without good students to teach,Geology at N.A.U. would lose its reasonfor being. Programs have been formulatedto prepare students, at the B.S. and M.S.levels, to enter into the mainstream ofindustry. We emphasize fundamentals inGeology as well as in the supportingsciences, rather than highly specializedand restricted areas of concentration. Asa consequence, our staff constitutes adiverse balance of several specialitiesintentionally designed to overlap andsupport each other. The staff consists ofnine full-time professors and fourpart-time adjunct professors from theU.S.G.S. Astrogeology Center inFlagstaff.

Foremost in 1974 was the meeting ofthe Rocky Mountain Section of theGeological Society of America, held inlate April. By a massive joint effort withthe U.S.G.S. Astrogeology Center, theDepartment hosted a highly successfulmeeting attended by 587 geologicalscientists. A total of 139 papers and 10field trips provided the participants witha full and varied exposure to the geologyof Northern Arizona and the surroundingarea. The N.A.U. staff and studentspresented 21 papers and led several fieldtrips. Especially prepared for this meetingwas a first-rate publication of 821 pages:Geology of Northern Arizona. This2-volume set contains 52 papers and 8field guides edited by members of thestaff of the U.S.G.S. Astrogeology Centerand the Department of Geology atN.A.U. (a few copies are still availablethrough the N.A.U. Bookstore).

Continued page 10

n'T'1\Rl1J\o.1T OF MININGLrC'UVlJV''L-L-l,'' ENGINEERING

\.-v .......,,"' ... OF MINES......." .... "CD'('TTV OF ARIZONA

of us in the fields of earthand mineral engineering

the energy crisis providednews and some bad news. We

linger on the bad news; there isto be said about long

and skyrocketing fuelwhereas we had long

in relative obscurity, lastfundamental impact of mineral

on the way we live waswi th unimpeachable

though energy was of primevery little imagination was

see analogous conditions withcommodities. At the same

concern over landuse became an important

both the mining and geologicalen!p'rl.I~ering fields. For both problems it

that mining engineers andengineers were part of the

sOlution, not part of the problem.

Department of Mining andiGe610ldcal Engineering offers courses of

geological engineering designedyoung men and women in the

sl'H~Ci:ali,~ed professional application ofin the fields of exploration for

of mineral resources, inengirleerirlg construction industry,

in related fields such asr-resource development,

storage of liquifiedproducts, and urban planning.

fields of study and research dealpriIl1:1riJv with the engineering aspects of

forces and materials and theand correlation of geologic

concerning them. The three majordiyisi()ns of study are geotechnics, dealing

fluid, soil and rock mechanics andengineering aspects of geology,

2:e(mhlv~ir~ hydrology, and other relatedmining geology and exploration

deposits; and geomechanics,with deformation phenomena in

masses due to imposed stresses andGeostatistics, the use of

ll1111tiivaria"te statistical methods as appliedsampling and analysis of geologic data,

an important role in the trainingresearch. Supporting courses are

re(luiired or elected in allied sciences andhum;anjiti(~s as well as from those given in

Department of Geosciences. Theoffers opportunities to earn

.S., M.S., and Ph.D. degrees inGeological Engineering.

Continued page 14

FIELDNOTES

U of A Continuedand faculty will indicate where ourinterests have developed in these areas.

Conodonts, which are tiny tooth- orjaw-shaped microfossils of unknownorigin, are proving to be a valuablebiostratigraphic tool in Arizona. Dr.Dietmar Schumacher presented evidenceat the Symposium on Northern ArizonaGeology concerning the age of thesequence of rocks east of the Grand WashCliffs that some geologists assign to theCambrian and others assign to theDevonian. Part of this controversialsequence at localities south of PeachSprings contains Upper Devonianconodonts.

University of Arizona

Field investigations are the backbone ofgeologic research. Here a student measuresthe thickness and attitude of a rockoutcrop.

Continuing research on conodonts inthe Martin Formation of Devonian ageindicates an age for most of the Martin asFrasnian (lower part of the UpperDevonian). A thin interval in the upperpart of the Martin is Famennian (upperpart of the Upper Devonian) in age andappears to be widespread in central andsoutheastern Arizona. Dr. Schumacherand his students are continuing to catalogPaleozoic invertebrate fossil localities inArizona and will also check the faunallists of these localities.

A catalog of Cenozoic vertebrate fossillocalities in Arizona was published by Dr.Everett H. Lindsay, Jr. and Norman T.Tessman in the February 1974 Journal ofthe Arizona Academy of Sciences andincludes faunal lists of 163 vertebratelocalities. They examined and checkedthe identification of fossil specimensfrom Arizona in the collections ofmuseums which have major collectionsfrom Arizona. New material from CaveCreek extended the Tertiary vertebrate

fossil record back into the middleOligocene. Other fossils from theOligocene and early and middle Mioceneepochs (which are middle Tertiary)include rhinoceroses, pocket mice, andcamel remains. Later Tertiary fossils aremore abundant with rodents, dogs,three-toes and single-toed horses, foxes,camels, llamas, mastodons, peccaries,ra b bi ts, bears, rac coons, weasels,pronghorns, beavers, etc. The latePliocene and Pleistocene fossils are quiteabundant and include those mentionedabove in addition to squirrels,woodchucks, pack rats and other rats,wolves, badgers, hyenas, shrews, bats,tortoises, gophers, ground sloths, pocketand other mice, kangaroo rats, cats,modern horses, deer, skunks, jaguars,toads and frogs, lizards and snakes,mammoths, ringtail cats, mountain goatsand sheep, elk, and bison.

Dr. Lindsay is also participating in aNational Science Foundation study of thepaleomagnetic stratigraphy of lateCenozoic sediments in the San PedroValley in southeastern Arizona. Ironcompounds in clay and sand line up withthe magnetic poles when they settle intolakes and streams. The magnetic poleshave reversed many times in the lastseveral million years and the ages anddurations of these reversals are nowknown back to 5 million years ago in thisarea. Dr. Lindsay is correlating thevertebrate faunas with the magneticchronology. Preliminary work indicatesthat the St. David Formation and theQuiburis Formation, which were thoughtto be deposited during different intervalsof time, have some overlap in theirmagnetic sequence.

Graduate student Louis Jacobs studiedthe small mammals in the QuiburisFormation near Redington and assigned amiddle-to-Iate middle Hemphillian landmammal age based on the stage ofevolution of the rodents. Potassium-argondates for volcanic tuffs andpaleomagnetic data from the QuiburisFormation indicate an age slightly olderthan 5 million years.

The University of Arizona Laboratoryof Paleontology is also continuing itsmastodon casting project under thedirection of Dr. Lindsay. Graduatestudent J. J. Saunders and vertebratepaleontology preparator Kevin Moodiehave developed several new techniques oflatex molding and fiberglass casting in theprocess of completing these mastodoncasts for display at the Osaka Museum ofNatural History and Illinois StateMuseum.

Mapping and radiocarbon dating of thelayered ground sloth dung deposits inRampart Cave and Muav Cave in thelower Grand Canyon have denoted whenthe ground sloth, which is extinct, lived

there. Dr. A. Long, R. M. Hansen, and Dr.P. S. Martin have published papers on thediet and the life and death of the Shastaground sloth. The sloths were mainlybrowsers on vegetation that is stillavailable in the area. Sloths used the cavebefore 24,000 years ago and between14,000 to 11,000 years ago. Radiocarbondates on ground sloth dung indicate theydisappeared about 500 years later inSouth America than in North America.This supports Dr. Paul Martin's theory ofoverkill by Paleoindians 11,000 years ago.Dr. Martin is continuing to accumulateevidence for Pleistocene overkill and iscurrently working with Dr. James E.Mosimann on simulating overkill byPal eoindians with mathematical(computer) models.

Thomas Van Devender studied packrat nests in the Sonoran desert for hisPh.D. dissertation and documented thechange in climate and accompanyingvegetation changes during the Wisconsin(latest glacial advance in North America)and post-glacial stages. The pack ratmiddens that yielded radiocarbon agedates between 30,000 to 11,000 yearsago contained about 30% woodlandplants which now occur at elevations262-662 meters (850-2150 feet) higherthan the pack rat midden collection sites.The cold-tolerant Mohave Desert plantsalso displaced the warmth-loving SonoranDesert plants at least 80 km (about 50miles) to the south. Van Devenderinferred the late Wisconsin climate had1.5-3.9° centigrade cooler annualtemperature and 8.2-22.0 centimeters(about 3-9 inches) greater annual rainfall.He accounts for this by a southward shiftin the winter storm tracks and concludesthat the ice age affected the climate andlife of southwestern Arizona onlyminimally and, perhaps, less than the restof the United States.

The first Paleozoic lepospondylamphibians discovered. in Arizona havebeen described in a master's thesis byDavid Thayer. The lepospondyls are agroup of amphibians to which themodern salamanders belong. Theiroccurrence in the Black Prince Limestonein the northern Swisshelm Mountains inCochise County makes that the earliestNorth American lepospondyl amphibiansite. The age of the fauna is LateMorrowan or Early Atokan (Early-earlyMiddle Pennsylvanian).

In the area of palynology, Dr. GerhardKremp has begun collecting publicationsin the field and compiling the pertinentinformation for mechanized data retrievalin his PALYNO DATA project. Electronphotomicrographs, which will be part ofan eventual atlas of southwestern pollengrains, have been published by Dr. A. M.Solomon, Dr. P. S. Martin, Dr. J. E. King,and J. Thomas in the Arizona Academy

ARIZONA B UREA U OF MINES

of Science Journal. The report alsoincludes a list of all species photographedand published to date. Dr. A. M.Solomon, J. L. Webb, and G. K. Kelsohave used pollen data collected from thecity of Tucson, San Xavier, and frompueblos in New Mexico to documentmodern and prehistoric disturbance ofarid lands by humans. W. G. Spauldingexamined the pollen content of mountainsheep fecal material collected from rockshelters for a master's thesis. The materialwas deposited only in the late springbetween 7000 and 2500 years ago.Springtime occupation of the rock shelterby the sheep ended about the time thatIndian occupation of a nearby rockshelter began during the spring pinyonnut season.


Carbon-14, a heavy radioactive isotope ofcarbon, is produced in nature and breaksdown at a constant rate of decay. BYmea suring the amount of Carbon-14remaining in carbon-bearing material, thedate of origin of the material, if formedwithin the last 50,000 years, can bedetermined within close limits. Here studentassistants are working in thegeochronological Carbon-14 preparationroom.

Coal samples, rock and soil samples,and rain runoff samples from the BlackMesa mining area in northeastern Arizonahave been analyzed for toxic traceelements. Dr. Austin Long and PeteKresan have used atomic absorption andneutron activation techniques for theseanalyses which have been documented inan interim report to the U.S. Bureau ofMines.

The stable isotope content of a parcelof water can indicate much about itshistory. Robin White and Dr. Long arebeginning analyses of rainwater, streamwater, and groundwater to characterizeTucson basin water. Mr. White's master'sthesis will discuss the processes that have

Dec. 1974

affected the groundwater and whetherthe groundwater in present use is similarto the water now entering the •groundwater reservoir. ,.

In a related Ph.D. dissertation, EdwardWallick developed a chemical-isotopicequilibrium model to adjust radiocarbonages of groundwater in the arid Tucsonbasin because of carbon-14 in calcite(caliche) in the soil.

Dr. D. E. Livingston is investigatingthe trace element geochemistry of thePrecambrian rocks of the upper and lowergranite gorges of the Grand Canyon.Livingston suggests in a Geol. Soc. Am.abstract that the rocks containing lowamounts of Rubidium were differentiatedbefore or during tectonic activity. Thehigh Rubidium group of metamorphosedclastic sedimentary rocks and igneousrocks of the upper gorge weredifferentiated late in the tectonism orafter the major tectonic activity.Preliminary Rubidium-Strontium agedates of the granite from PhantomCanyon and the Trinity Gneiss are 1650million years old and 1700-1850 millionyears, respectively. Other material isbeing analyzed for additional age dates.

"Younger" Precambrian igneous rocksof central Arizona have been analyzed byDr. Livingston for Strontium isotopicratios and Rubidium and Strontiumabundances. The diabase (amedium-grained, black, igneous rock)which intrudes both the Apache Groupand the Troy Quartzite in the SierraAncha Mountains yields a good age dateof approximately 1200 million years ago.Some diabase which intrudes the CityCreek series in the Mazatzal Mountainsyields a preliminary age date of 1300million years.

Numerous Potassium-Argon age dateshave been published through thecontinuing National Science Foundationgrant to Dr. P. E. Damon and hislaboratory on "The Correlation andChronology of Ore Deposits and VolcanicRocks."

Dr. Livingston has suggested in a paperin Earth and Planetary Science Lettersthat the ages and locations of copperporphyry deposits in the southern Basinand Range Province indicate the directionof continental drift in the area. Thecopper deposits were emplaced under theinfluence of.a mantle hot spot as this partof the North American plate movedN35-400W during the time of theLaramide orogeny 72-52 million yearsago.

The age and Strontium isotope ratiosof the LaCaridad, Sonora copper_porphyry deposit have been published by •Dr. Livingston in the Geol. Soc. Am.Abstracts. It is the youngest, 53 millionyears old, and southernmost of theLaramide deposits so far dated.

Continued page 12

Arizona State University

Spectacular earthcracks in caliche-cemented alluvium occur in many valley areas of southernArizona and are often due to land SUbsidence caused by ground-water withdrawal. Recognitionof this hazard is important in land use planning and is the subject of geological research. Herewe are looking north to the Gold Mine Mountains from the south side of Chandler Heights onHunt Road, 1'/4 miles east of Powers Road on the boundary between Maricopa and PinalCounties. The crack is open to a depth of at least 50 feet.

No.4

ASLJ. 1 companies and other

'ndustrt.ans including the cities of1 'zatlo , Th 1 forgan1. nd scottsdale. e resu ts 0

IJItoenlX ad1'es are published in state,stu . 1 . t'f'tItese and internatIOna sClen 1 1C

natiOnal,jOurnals. ber of graduate students and

A num are involved in timelyfacul tY ntal geological and geochemicalenvironmet l'S the use of the principles of

k tIta, . t 'dwor, nd geochemIstry 0 proVl e ageolOgy ~erstanding of man's use of andbetter un the environment. Dr. Williamimpact ~n nd a graduate student have justA. sau~ ; a much used, detailed, andcomple ~ geophysical study of Paradiseup_to-da e r Scottsdale, which indicates a

1 Y neaval. e ent-filled valley at least 9000 ~efetsed1m with ground water to satls ydeeP d Ie's present demand forscotts. aatelY 130 years.approx1m've ground water withdrawal in

Excesfrizona has created a geologiccentral . the form of dangerousIt az~rd cr: cracks which may be up to 50subSlden 6 feet wide, and hundreds offeet deep, These are being studied by Drs.feet long· d Donal M. Ragan, who are,'

k an h' , dSauc 1 studying t e ongm ancurrentYn of these cracks. A graduatedistribut10 der the direction of Dr. Raganstudent U~eted a study to deten;nine thejust comP ntrolling crack locatIOn andfactors cOossible mechanisms of crackxplore p

~ormation. ality and quantity of groundThe q.~ important to Arizona.

water 1t chromium and nitrate contentIIexavalend water in parts of Paradiseof groU~ar scottsdale locally exceeds theValleY n established health standards.limit for rch projects under the directionTWO res~ichael F. Sheridan and Burr A.of Drs. re near completion whichS il~er e athe hazardous areas and offerdeltneat mendations for futurer e com ent. Dr. Carelton B. Moore anddeveloP~e student ha~e ju.st co.mpleted aa gradU f boron distnbutIOn m naturalstudY °and sewage effluent in Arizona.waters as have higher boron contentDesert ar~orthern part of the state andtl1an tl1C

l1Ccontent is high enough to be

10ca~IY t tal to citrus growth. Research bydetrtmen R Buseck and graduate studentspr. peter i~g methods for the chemicalis dev~IOPof particulate air pollution.analysISate air pollutants are a specialpartlcul in Arizona and currentprob~e:s are not equal to the task oftecl1n1Q. ing the sources of thesedeterm1tnS The primary analytical tool

t 'CUla e ' 'bpar 1 , is the electron mlCropro efor tillS an instrument able to doana1y~eri analysis on particles less than 1cnem1ca (l: 25 ,000th of an inch) inmicron The total investment in thediameter.y facilities for this purposelaborator

FIELDNOTES

approaches a quarter of a million dollarsand permits a very powerful means forattacking this serious problem.

Two timely projects involving threegraduate students, under the direction ofDr. Troy L. Pewe, concern theenvironmental geological mapping of thePhoenix Mountains in Phoenix and theMcDowell Mountains near the city ofScottsdale. Phoenix and Scottsdale areamong the pioneers in the United Statesto solely fund such land use geologicstudies. Similar studies by three studentsunder the direction of Dr. Silver areunder way in the Pinnacle Peak areanortheast of Phoenix and the ApacheJunction area near the SuperstitionMountains. These geologic studies are thefirst to be supported by corporations anddevelopers in the Phoenix area. Frombasic geologic maps it is possible toprovide land use information toarchitects, land planners, city officials,engineers and others, These basic earth

science data are presented on derivativemaps in layman's language. Derivativemaps include those dealing with sand andgravel resources, ground water, soilexcavation and foundation problems, andgeologic hazards such as flooding.

The lower Verde River Valley has beenmapped geologically under the guidanceof Dr. Pewe and provides information fornecessary geologic background ofconstruction sites for planned settlementsas well as background for CAP reservoirstudies,

Investigations of geothermal waterchemistry at potential geothermal siteshave been undertaken by Dr. Sheridanand a graduate student. Several areas ofpotentially high reservoir temperatureswere determined through Na/K and Si02content of thermal spring water. Dr.Sauck is continuing an evaluation of thegeothermal ground noise phenomenon asan exploration tool. Most geothermalareas appear to have a characteristic low


Geophysics, a means of determining geologic features beneath the surface of the earththrough measurements of natural earth currents, applied electric currents, heat flow, magneticproperties, radioactivity, seismic response, and gravity, has an important role in geologicresearch. The photograph shows A.S.U. students measuring seismic velocities in order todetermine the thickness of overburden. The hammer produces shock waves that are recorded bythe geophones spaced along the Wire, and the reSUlts are read on the seismic refraction amplifierand camera console. Such portable units have many uses related to investigations ofgroundwater, stratigraphy, and structure.

level, nearly continuous seismic signaturein the range of 1 to 20 Hz. A graduatestudent of Dr. Buseck's is testing mercurygeochemical prospecting as a means forlocating buried geothermal sources.

A seismographic station that is part ofthe cooperative Epicenter Program hasbeen operating continuously sinceNovember, 1971 and reports monthly tothe U.S. Geological Survey. The stationconsists of a long period horizontalseismograph under the supervision of Dr.Sauck.

The magnetic character of a porphyrycopper deposit was investigated by agraduate student guided by Dr. Sauck. Hemeasured the magnetic susceptibility ofdrill cores from the CONOCO PostonButte deposit and correlated theirmagnetic response with lithology andalteration. His work matched well with asurface magnetic survey.

Two recent long-term projects givedetailed information on large scalemapping of the two high peak areas ofArizona; under the direction of Dr. Pewe,the volcanic geology of the San FranciscoPeaks and White Mountains, as well as theglacial deposits, are now well known. TheSan Francisco Peaks that are now knownto have formed in about the last 2 millionyears are now the center of intense workbecause of geothermal possibilities. Inaddition to 150 chemical analyses used inthe above mapping project, a long-termproject has been under way by Drs.Moore and Holloway on the geochemistryof the San Francisco Peaks. More than100 maj or element chemical analyseshave been made and work is nowconcentrating on trace elements. TheWhite Mountains of eastern Arizona onthe Colorado Plateau are about 9 millionyears old and represent a dissectedcomposite volcano built up overthe years; they have been glaciated in thelast 200,000 years. Basic geologicalinformation is now available for land useinterpretation of both of these volcanicareas.

Research projects in sedimentologyand physical stratigraphy at Arizona StateUniversity range from recent marinestudies in the Sea of Cortez toreconstruction of Mississippian carbonateenvironments of Arizona. Emphasis isplaced on problems which provideadditional background for understandingfossil fuel and ground water potential ofArizona host rocks and reservoirs. Fore;JCample, a recently completed study onthe Dakota Formation of the Black MesaBasin guided by Dr. Silver resulted in abetter understanding of the origin anddistribution of coal in the formation aswell as better delineation of potentialground water reservoirs. Other projects inthis general area of research includestratigraphy of the Supai Formation in


central Arizona, carbonate diagenesis ofthe Virgin Limestone, Nevada, reservoirpotential of the Escabrosa Limestone,and diagenesis of sedimentary carbonates.Projects in the incipient stage by Dr.Silver and his students includedepositional patterns of the EscabrosaLimestone in Arizona and northernSonora, Mexico, and deltaicsedimentation of the Toreva Sandstone,Black Mesa Basin.

A comprehensive study of thestratigraphic and geographic distributionof conodonts in Mississippian rocks of

Dec. 1974

Arizona was begun in 1969 by Dr. RobertF. Lundin and graduate students. Thefirst studies covered southeastern andeast-central Arizona. A project under wayincludes the Chino Valley and centralGrand Canyon region. Preliminarysampling has been completed in thenorthwestern corner of the state.

These studies have led to correlationof the Escabrosa Limestone and RedwallLimestone (of east-central Arizona) withrocks ranging from middle Kinderhookian(Upper Choteau) to middle Meramecian(St. Louis) in age in the type area of the

------_........_---------------~---

___________________________,,4

characterization and description of newmeteorites using atomic absorption,scanning electron microscope,transmission electron microscope,electron microprobe, and combustionanalysis techniques, as well as the moreclassical methods. A major program forthe analysis of amino acids and otherorganic compounds in carbonaceouschondrites has been initiated inconjunction with the ASU Department ofChemistry and the NASA Ames ResearchCenter. Also, studies of the metallicfragments in the vicinity of BarringerMeteorite Crater near Winslow are underway by Dr. Moore.

The geochemistry of the volatileelements carbon, sulfur, and nitrogen inigneous rocks and lunar samples is beingstudied by Dr. Moore and a graduatestudent. The moon samples are depletedin carbon and nitrogen as compared tothe earth but appear similar in total sulfurcontent. Studies of sulfur in basalts fromnorthern Arizona may shed light onsources of sulfates in the soils of theupper Verde Valley and the PaintedDesert areas.

Dr. John W. Larimer is continuingstudies aimed at understanding thechemical and physical processes that wereoperative in the primitive solar nebuladuring the time the planets and otherobjects were forming. This researchinvolves extensive calculation to predictthe condensation temperatures of variouskey elements and stability fields of keyminerals in a cooling gas of solarcomposition. The predictions are thencompared to the composition andmineralogy of meteorites primarily, butalso to terrestrial and lunar rocks. Forexample, the deficiency of elements suchas Pb, Bi, In and Tl in meteorites,coupled with the presence of FeS andlack of Fe304 points to a formationtemperature of 400 to 500oK. Thesestudies are now being extended to therare, highly reduced meteorites whichappear to have evolved in a carbon-richregion of the nebula. Another currentstudy is aimed at predicting the history ofmetallic trace elements. These results willbe useful in testing the competinghypotheses of whether the earth accretedheterogeneously, in a layer -cake fashionfrom the core outward, orhomogeneously, in which the metalinitially was distributed uniformly butlater segregated to form the core.

Peridot Mesa on the San Carlos IndianReservation has been a world-famoussource of the semiprecious gem peridotfor many years. The peridot crystals andthe basaltic lava flow in which they occurare also of great scientific interest becausethey appear to have originated at greatdepth (about 15-20 miles) below theearth's surface, that is, near the

Continued page 10

FIELDNOTES


What is it? These small, tooth- orplate-like fossils, called conodonts, are amystery as to their origin and biologicfunction but have become very useful inidentifying and correlating rock units on thebasis of the fossil contents. They are foundin rocks ranging in age from MiddleCambrian to Upper Triassic. Pictured here isa new conodont, approximately 2 mm long,from the Redwall Limestone ofMississippian age.

In the field of solid state geochemistry,Dr. Buseck has been studying thestructure of minerals using highresolution electron microscopy. By usingthe transmission electron microscope, heand his students are able to increase thevolumetric resolution by 15 orders ofmagnitude (l015) and consequently seefor the first time a great deal offine-structure previously unsuspected.They study and photograph individualclusters and rows of atoms both in oreminerals and in silicates. The techniqueswhich are being pioneered by Dr. Buseckand his students here will eventually findthemselves used in most if not all of thelarger geology departments around thecountry - within 5 or 10 years everydepartment that now has an x-raydiffractometer will find it advantageousto also have a high resolution electronmicroscope.

Meteorites are of particular interestbecause they are samples from the outerregions of the solar system and thusprovide us information from areas thatare otherwise inaccessible. The Center forMeteorite Studies at Arizona StateUniversity, under the directorship of Dr.Moore, houses a collection of now morethan 1000 different meteorite specimensfrom different localities, making it one ofthe four or five largest collections in theworld. The Center has a publication seriesand research program. Maj or researchefforts by Drs. Moore, Buseck, Larimer,and graduate students include the

sensitive, field portable instrument fordetecting mercury at the part-per-billionlevel. The instrument is the size of ashoebox, is easy to operate and transportinto the field, and is both less expensiveand more sensitive than existinginstruments. It is used to detect mercuryconcentrations at the surface fromdeposits that are buried by hundreds offeet of alluvium, glacial debris, or perhapseven volcanic rocks. They also arestudying the mineralogy of the weatheredzone of porphyry copper deposits as anaid to prospecting for buried copperdeposits.

Recognition of sixIles has made a refined'Csubdivision of these rocks

CC ordingly, Mississippian()ua is better known. Suchion is important in thedgas in Arizona.

s proceeding on aesurvey of the Precambrianrocks present in the several

l()cks which surround theteSun. Under the general

])r. Ragan, some of theBeen done in conjunctionHldies, including Mummy

pegmatites and thetal studies listed above.eVeral hundred square miles

&fly surveyed, and severals<cnosen for more detailedsi""ork progresses, the resultse<an important contributionstanding of the Precambriantral Arizona.'dan has been studyingHillary volcanic deposits inadfic area and Arizona todel of pyroclastic transport.

()del of eruption is an initialstem above the vent that"f>moves laterally by windbYi ground-hugging surges. Afieation of primary texturesabetter understanding of theeeruption and emplacement

volcanic clouds in Arizona

art rock units found in theMountains and adjacent

as. Drs. Sheridan and Raganted an attack on theal mechanical processesthe eruption, transport, andof ash from tuffs and relatedhas been found possible to

Uch of the post-eruptivetudying the grain structure of

ted ash deposits, and bylie strain history in compactednits.tion of a long-term projectI students is the detailed studyetation of volcanic geology of

istition Mountains, Goldfield,and other volcanic mountains

Salt River east of Phoenix.huge calderas have beenand work by several graduatender the guidance of Dr.

has provided moderntion of the type and origin ofand perhaps associatedzation in similar calderants.

-seck and students working onposits are concerned withcal prospecting for buried orethe development of supergeneand their use for searching forhave developed a new, highly

ARIZONA BUREA U OF MINES

Northern Arizona University

The deep gorge of the Colorado River exposes geologic formations dating back to olderPrecambrian time (some 1.7 billion years) which record the geologic history of the area. Note howthe various fromations have characteristic physiographic exposures such as cliffs, slopes, or benchesdepending on their physical and chemical character. Here Dr. Dale Nations and students at N.A.U.,on a field trip, are on a bench formed on the Redwall Limestone of Mississippian age (some345-320 million years ago).

Arizona Bureau of Mines

The Mogollon Rim is a striking physiographic feature in central Arizona, forming a breakbetween the relatively flat Colorado Plateau to the north and the rough, mountainous transitionzone and the Basin and Range Province to the south. The view is to the southwest from the Rimeast of Payson with the Coconino Sandstone of Permian age (some 280-225 million years ago) inthe foreground, and Precambrian rocks and the Mazatzal Mountains beyond. The complexformational and structural relationships of the Rim country offers a challenge to geologicalresearch.

Dec. 1974

,

rZ

FIELDNOTES

Arizona Bureau of Mines

Complex block-faulted mountain ranges with intervening alluvium-filled valleys are the mainfeatures of southern Arizona. Many such ranges are the sites of important mineral deposits andboth mountains and valleys offer students and faculty many research problems in numerous fieldsof geology. Here we are looking east across the Santa Cruz Valley to the Santa Rita Mountains,south of Tucson.


Geology students from A.S.U. on a field trip to the San Francisco Peaks near Flagstaff.Research projects on the glacial deposits. volcanic rocks. and physiographic features of this areahave been carried out for many years by faculty and graduate students of A.S.U., N.A.U., and U.ofA. The view is to the east down the interior valley. exposing the glacial deposits. The main peaksare about 2 million years old. Sugarloaf Mountain at the mouth of the valley, in the middle, is250,000 years old and was emplaced following an explosive ash surge. Sunset Crater, in the farmiddle right, is 900 years old.

ASU Continuedcrust-mantle boundary. In addition to theperidot (which is a variety of the mineralolivine), many other interesting mineralsoccur in the lava flow. Dr. John R.Holloway and graduate students arestudying the chemical properties of theseminerals and rock in several of these lavaflows in the San Carlos area, to determinethe pressure, temperature and chemicalconditions existing near the crust-mantleboundary beneath Arizona. Suchinformation is of great value in theunderstanding of the origin of volcanoesand ore deposits. To aid in thatdetermination, they use in the laboratorya special pressure apparatus in which theycan simulate the very high pressure andtemperature found at great depth belowthe earth's surface. The results of theseexperiments are minaturized lavas whichclosely resemble those found at SanCarlos.

In addition to teaching and researchwith undergraduate and graduatestudents, the Department long has beenassociated with Earth Science educationfor High School teachers. Dr. Paul T.Miller has directed and taught in manyNational Science Foundation supportedSummer Institutes and Academic YearInstitutes for Earth Science teachers andSecondary School Science teachers atASU. Geology (Earth Science) as asubject taught in High Schools has had aphenomenal growth in Arizona since theearly 1960s. In Maricopa County alone ithas increased from a few classes in oneschool to several classes in most of theschools. It is conservatively estimatedthat in Maricopa County there are morethan 8000 students enrolled in EarthScience classes at present. It is in partfrom this growing group that futuregeology students will be derived for thethree State Universities and, therefore,later for service as teachers andresearchers in geology in Arizona.

At present, Dr. Miller is conducting apilot program for the Earth Scienceteachers of Maricopa County for theSouthwest Section of the NationalAssociation of Geology Teachers to fostera closer relationship and exchange ofinformation among High School EarthScience teachers.

The faculty of the GeologyDepartment of Arizona State Universityare training students for various levels ofteaching as well as for geological researchin Arizona and throughout the country.Some graduates occupy positions in themining industry in the State, and othersare employed by petroleum companies inthe western United States. Geologistsserve with State and Federal GeologicalSurveys and with many of the Stateorganizations dealing with oil, gas, water,and mining. Other graduates areconcerned with land planning and

ARIZONA BUREAU OF MINES

utilization, pollution control, and areassociated with various consulting firmslocally and in the Southwest.

The Department of Geology at ASU isgrowing rapidly, and nearing completionis a 6-story Geology-Physics buildinggenerously funded by the taxpayers ofArizona. The geological and geochemicalresearch conducted by the faculty andstudents is contantly solving problemsvital to further growth and developmentof Arizona, from finding better methodsfor outlining ground water supplies,potential petroleum fields, or newmineral deposits, to better use of theenvironment through wise application ofthe principles of earth science.

NAU Continued

In the 1974 academic year,enrollments in geology courses broke allrecords. Although the number of majorswas held steady (130 undergrad and 35graduate students), the large number ofnon-majors taking Geology resulted in anincrease in enrollment of 21 % over lastyear. For geology graduates, theemployment prospects were and continueto be excellent. Many students receivedseveral job offers and every graduate iscurrently professionally employed.Eighteen major petroleum and miningcompanies, technical consultants, and theU.S.G.S. hired our students, with manycompanies interviewing on campus. Theprospects for June 1975 look evenbrigh ter as demand for geologistscontinues to increase as mineral andenergy resources become increasinglycritical.

Finally a large number of lessspectacular but significantaccomplishments were made, chief ofwhich was approval of a new seismicobservatory, and an agreement with theGrand Canyon National Park forsupplying staff and students in the visitorprogram. In the latter area, the staff willteach courses in geology to Parkpersonnel and graduate students willexplain geology and conduct field tripsfor visitors to the Park.

The research investigations of the staffand students continue to diversify andintensify in an attempt to comprehendthe geology of northern Arizona and toapply this new knowledge to thebetterment of society. Our researchefforts have been grouped into fivecategories and hopefully will providesome insight into our activities, interests,and accomplishments.

Dr. David S. Brumbaugh has beeninvolved in geophysical studies focusedchiefly on structural problems. The GrayMountain Monocline, north of Flagstaff,has been studied using both gravity andmagnetic mapping programs andcomputer modelling. Other monoclines in

Dec. 1974

the transitional zone near Paulden,Arizona are also currently beinginvestigated using these tools. TheAnderson Mesa fault zone near LakeMary was studied by Dr. Errol L.Montgomery using magnetic and gravityprofiling and modelling in order todelineate structural controls.

Using geophysics, Dr. Montgomeryalso is cooperating with the City ofFlagstaff for continued exploitation ofgroundwater resources. Because volcanicand structural features are chief controlsfor the occurrence and circulation ofgroundwater in the Flagstaff area,geophysical methods are quite useful ingroundwater studies. Reports givingresults of these studies are available forthe Wood Mountain, Lake Mary, and SanFrancisco Mountain Inner Basin well fieldareas.

A magnetic map of western Flagstaff isnow available together with engineeringgeology data of the entire Flagstaff area.Geologic mapping for these and otherprojects was compiled and is nowavailable. Further mapping, includingland capability studies for Flagstaff, willbe available in the near future.

Research in structural geology by Dr.Charles W. Barnes, Dr. Brumbaugh, andseven graduate students has beenconcentrated in two somewhat diverseareas: understanding the evolution ofmonoclines such as that at GrayMountain, and Precambrian polyphasedeformation and metamorphism.

Recent research includes mapping inthe southeastern intersection areas of theGrandview, Black Point, and East Kaibabmonoclines northwest of WupatkiNational Monument and northwestwardinto the eastern Grand Canyon.

Precambrian research has includedwork on the Vishnu structure in theBright Angel area of the Grand Canyon, alit-par-lit terrane near Skull Valley,southwest of Prescott, and the MatzatzalQuartzite near Del Rio, north of Prescott.Further, a detailed structural study in theBig Chief Mine area, east of Jerome,includes not only some interesting newdata on the time evolution of the MingusMountain frontal fault system, but also areinterpretation of some of thevolcanogenic sulfide deposits in the area.

Research in igneous petrology underDrs. Richard F. Holm, Raymond L.Eastwood, and Edward W. Wolfe,Adjunct Professor from the U.S.G.S.Astrogeology Center, is centered in theSan Franciso Volcanic Field. Severallong-term projects, in the initial stages,are determining the field relationships ofthe various volcanic units and interpretingthese data in terms of the volcanologicaland structural development of the SanFrancisco Volcanic Field.

A major current project involves a

Canyon are all being investigated. Inaddition, one major paper has beenpublished on the biostratigraphy of thePliocene-Pleistocene Verde Formationand research is continuing on thepaleontology and paleoecology of thisunit.

The sedimentary rocks in northernArizona have been investigated by severalstaff members and graduate students.Research by Dr. Augustus S. Cotera Jr. isalmost complete in two Precambriansandstones, the Shinumo and HakataiFormation in the inner gorge of theGrand Canyon. Together with completedstudies of the other units in the Unkar

FIELDNOTES

Northern Arizona University

The Grand Canyon of the Colorado River has been the subject of geologic study andresearch since the time of John Wesley Powell's historic pioneer river trip through the canyon,over a century ago. It continues to present intriguing geological problems to university facultyand students. The view is one looking downstream in upper Marble Gorge.

Naco Formation in Central Arizona, isproceeding satisfactorily and one paperhas already been submitted forpublication.

Considerable work is in progress byDrs. 1. Dale Nations and Thor N. V.Karlstom, Adjunct Professor from theU.S.G.S. Astrogeology Center, in theMesozoic and Cenozoic in the generalarea of northeastern Arizona. Thepaleontology and paleoecology of theCretaceous Fruitland Formation innorthwestern New Mexico, the TriassicMoenkopi near Meteor Crater, theCretaceous Mancos Shale in Black Mesa,the Holocene Naha Formation in Tsegi

structural, stratigraphic, andstudy of the San Francisco

Volcano north of Flagstaff. Thisis designed to provide a better

of the geological andevolution of the volcano

its role in the development of the SanFnlllcisco Volcanic Field.

A second project consists of studies tobetter understand the geological and

evolution of smaller silicicof the volcanic field. Two recent

ate theses have made majorto this project. One, by

hades Kluth, describes thevolcanological and structuraldevelopment of Elden Mountain, on thenorthern outskirts of Flagstaff. Thesecond, by Kent Murray, is a study ofWilliams Mountain, a complex of silicicdomes, east of Flagstaff.

A third long-term project is designedto better understand the structural,volcanological, and petrochemicalevolution of a part of the San FranciscoVolcanic Field between the San FranciscoPeaks and the Mogollon Rim. This projecthas involved studies of detailedrelationships between volcanism andfaulting, including the Oak Creek Fault,in the Woody Mountain area southwest ofFlagstaff and of Shadow Mountain, thenorthernmost vent of the San FranciscoField. Finally, a reconnaissance geologicmap of part of the Coconino NationalForest is being prepared in cooperationwith the U.S. Forest Service that involvesdetailed structural, volcanological, andpetrographic studies of the area betweenAnderson Mesa on the east and SycamoreCanyon on the west.

In other areas of Arizona, graduatetheses related to igneous petrology havebeen completed or are in progress andinclude a detailed study of the youngerPrecambrian basaltic rocks of the GrandCanyon by John Hendrix; a massivecalcite body (a possible carbonatite) nearWickenburg by David Sanders; anemplacement of Precambrian granite nearPayson by Rondi Martinsen; and a fieldstudy of Older Precambrian metamorphicand plutonic igneous rocks at WebleMountain, southwest of Buckeye,Arizona, by Carl Smith.

A major project involving theBiostratigraphy of the Devonian systemin northern Arizona is being done by Dr.Stanley S. Beus and two graduatestudents. One major paper on the generalstratigraphy has been published and workis continuing on the Paleontology andPaleoecology of the system, particularlyin northwestern Arizona. Also in thisarea, a thesis project by John Matthewshas been initiated on the generalPaleozoic stratigraphy in the WheelerRidge area.

Paleontological studies of thePennsylvanian system, especially the

Group of the younger Precambrian, thisresearch will be submitted as a specialpublication to the GSA and will provide acomplete summary of the petrology,sedimentary structures andpaleogeographic interpretation of theUnkar Group. In addition, work has beenini tia ted on the stratigraphy andsedimentology of the NankoweapFormation, which overlies the UnkarGroup in the inner gorge of the GrandCanyon.

A second research area has beenfocused on facies analysis of severalcarbonate units in the Paleozoic rocks ofnorthern Arizona. Studies are completeand published on the marine facies of theToroweap Formation, and further studiesare being extended into Utah and Nevada.Analysis of the non-marine facies in theToroweap has also been completed andpublished. Further carbonate research invarious units of the Mississippian,Devonian, and Permian systems innorthern Arizona are in progress with thepetrographic facies analysis of theRedwall Limestone in Chino-VerdeValley virtually complete.

Dr. John D. Strobell, AdjunctProfessor from the U.S.G.S. AstrogeologyCenter, in Stratigraphy and EconomicGeology, is continuing his research on theoil and gas possibilities of the ColoradoPlateau. Dr. John F. McCauley, AdjunctProfessor of Lunar and Space Geologyfrom the U.S.G.S. Astrogeology Center, iscooperating with Dr. Cotera on the sanddune landscape project on the NavajoReservation.

From the above summary of researchin Geology at Northern ArizonaUniversity, it is evident that we do a lotof field work. In northern Arizona, wehave an excellent field laboratory and it isour firm contention that our studentslearn geological principles best in thefield, where geology is. We should like toextend a sincere invitation to you, thereader, to come up into the high countryand visit with us. We will delight insharing this magnificent country with youat any time.

U of A Continued

Molybdenum mineralization appears tobe about 4 million years younger than themain phase of copper mineralization.

The Potassium-Argon dates, patternsof eruption, and periods of mineralizationof the Tertiary volcanic rocks of theMogollon-Datil Province of New Mexicoand surrounding regions were publishedin the Geol. Soc. Am. Bull. by W. E.Elston, P. E. Damon, P. J. Coney, R. C.Rhodes, E. I. Smith, and M. Bikerman.They found three major volcanic cycles28-23 m.y. and 23-30 m.y., each ofwhich consists first of andesite to rhyloitelava flows, then ash-flow-tuffs, and ends


with basaltic andesite lava flows. Alkalibasalt and tholeiite (basalt poor inolivine) became the most common typesof volcanic rocks after 20 million yearsago.

Dr. P. E. Damon, M. Shafiqullah, andD. J. Lynch have determinedPotassium-Argon age dates of 12 to 17million years on volcanic rocks associatedwith Miocene sediments which have aprofound angular unconformity. Thisunconformity is the result of faulting,tilting, and erosion, after which othersediments were deposited on the angularsurface. After 12 million years ago, thebasins have been subsiding relative to theranges with only minor tilting of thestrata. Several basins contain salt oranh yd rite, which indicates extremeevaporite conditions during late Mioceneand Pliocene time.

Potassium-Argon age dates of over 30volcanic rocks in the San FranciscoVolcanic Field have been used by Dr.Damon, Dr. Shafiqullah, and 1. S.Leventhal to calculate the rate of erosionof the Little Colorado River. During thelast 2.4 million years, the average rate ofdowncutting has been 315 feet permillion years. Most of the erosion of theLittle Colorado River occurred during theHemphillian, before the Bidahochi lakebeds were deposited. Their chronology isconsistent with M. E. Cooley's (1962)geomorphologic classification of volcanicstages.

A Potassium-Argon date of 6.7 millionyears has been published by R. E.Scarborough, P. E. Damon, and M.Shafiqullah for a basalt of the middlevolcanic member of the BidahochiFormation about 2 miles northwest ofWhite Cone on the Navajo Reservation.This lava flow occurred after the lakedeposits of Pliocene aged Hopi Lake andbefore the Pliocene stream deposits in thesame area.

A reliable conversion table fromradiocarbon years to tree ring years hasbeen published by Dr. Damon, Dr. Long,and Dr. E. I. Wallick. The conversionchart covers the last 7355 years beforepresent (before 1950 A.D.), although theradiocarbon time scale is more preciselydefined from 500 through 2200 yearsB.C.

Dr. Spencer Titley has publishedseveral articles concerning the tectonicframework of southeastern Arizonaporphyry copper deposits and criteriaapplicable to the search for them. Dr.Titley is also the author of an article inFieldnotes on "Copper Mining and LandUse Planning."

Dr. Denis Norton is studying the heatand mass transfer in and around igenousbodies. The cooling process is relevant tometamorphism and to hydrothermalprocesses which are very important informing ore deposits. In a related research

Dec. 1974

project, Dr. Norton is using the theory ofchemical mass transfer to interpret dataon characteristic mineral zones inporphyry copper deposits. Dr. Norton isalso applying mathematical modeling andfield investigations to a feasibility studyfor evaluating geothermal water resourcesin Arizona.

Dr. J. M. Guilbert and 1. D. Lowellhave published information on variationsin zoning patterns in porphyry oredeposits in the Bull. Can. Inst. Min. Atalk to the Min. Society of America onhypogene mineralogy of porphyry basemetal deposits is also an outgrowth of Dr.Guilbert's continuing research on hechemistry, mineralogy, and environmentof porphyry copper deposits. Dr. Guilbertis directing numerous graduate studentinvestigations in this project. Some ofthese include Verl Smith on Alteration atEsperanza and Hypogene and SupergeneAlteration, John Mohon onSodium/Potassium ratios in micas, DarrellDean on Alteration at El Alacran, ClancyWendt on Alteration at Batamote, andRoger Laine on Geochemistry ofAlteration. Jerry Davis has investigatedthe alteration, fluid inclusiongeothermometry, and trace elementsgeochemistry of drill core samples fromSan Manuel-Kalamazoo for his Ph.D.dissertation, which will be published inEconomic Geology when it is completed.Dr. Guilbert has also given several talkson natural resource consumptions,shortfalls, and planning.

David Spatz has completed a master'sthesis on the geology andalteration-mineralization zoning of thePine Flat prophyry copper occurrence inYavapai County. He concluded thatmineralization is probablytime-correlative with alteration sincecopper recurs with main-stage alterationand lead and zinc with late-stagealteration. Current erosional truncationhas exposed a shallow level of the originalintrusive complex and the techniquesused in the thesis offer useful guides toexploration.

Although much of Dr. W. B. Bull'spublished research uses examples fromCalifornia, the processes are applicablefor Arizona as well. His article in theGeol. Soc. Amer. on geologic factorsaffecting compaction of deposits in a landsubsidence area is applicable to southernArizona valleys such as the Picacho-Eloyarea.

The impact of mining gravel fromurban streambeds in the southwesternUnited States was pointed out in anarticle in Geology by Dr. W. B. Bull andK. M. Scott. Digging gravel pits in thestream bottom lowers the local base levelwhich causes erosion of the streambottom upstream from the pit andendangers bridge piers. The stream banksalso become more susceptible to erosion.

water recharge is also reducedclay is deposited in the. bottom of

pits from the muddy poolsafter rains. Because inactive channelseasily become active, gravel mining in

channels poses the same majorto upstream bridges and housing

Dr. W. B. Bull has also developedequations to analyze the landforms nearthe mountain to basin boundary andpredict present stability. Dr. Bull has alsoinvestigated the playa (dry lake) processesin the volcanic craters of the SierraPinacate, Sonora, Mexico. Dr. Bull ispresently researching the Quaternaryalluvium and terraces of the LowerColorado River. The terrace profilessuggest that they were deposited as abraided river and that there has been novertical uplift since the terraces wereformed in the Holocene.

A comprehensive catalog of mineraloccurrences in Arizona has been preparedby Dr. J. W. Anthony, Dr. S. A. Williams,and R. A. Bideaux. The book, which willbe published by the University of ArizonaPress, recognizes about 585 mineralspecies. It is arranged by county andmining district and includes descriptionsof the most interesting mineraloccurrences. The book will be illustratedwith line drawings and color plates.

Dr. Anthony and Dr. W. J. McLeanhave also described a new mineral,jurbanite, a hydrous aluminum sulfate,from the nOO-foot level of the SanManuel mine north of Tucson.

Dr. Richard F. Wilson has written asummary of the Mesozoic stratigraphy ofnortheastern Arizona for the 1974Flagstaff meeting of the GeologicalSociety of America. Dr. Wilson is alsocurrently collecting data for astratigraphic atlas of Paleozoic andMesozoic formations of Arizona andadjacent regions.

Dr. 1. F. Schreiber, Jr. and hisgraduate students are continuing researchon coastal geology studies near PuertoPen as co, Son 0 r a , Me xi co. Asedimentation survey of Rose CanyonLake, Santa Catalina Mountains is also inprogress.

A master's thesis by William Jones hasunraveled the general geology of thenorthern portion of the Ajo Range inPima County. The Ajo Range isprincipally composed of mid-Tertiaryvolcanic rocks and has been tiltedeastward approximately 25 degrees alongnorth-northwest trending normal faults.

Constance N. Dodge has analyzed andcompared the pebbles from the Chinleand Morrison formations in Arizona andNew Mexico for a master's thesis. Theplace the distinctive pebbles (such asfossiliferous, volcanic, and white chertpebbles) came from was probably movedby strike-slip faulting (with horizontal

FIELDNOTES

movement of adjacent masses) betweenthe Late Triassic of the Chinle Formation

I and the Late Jurassic of the MorrisonFormation.

Dr. G. H. Davis and his students havewritten several papers about themid-Tertiary gravity-glide folding off theRincon Mountains near Tucson. The mainmountain mass, which is composed ofCatalina Gneiss, was uplifted relative tothe basin between 20 and 24 million


Excellent exposures, such as shown herein the Mescal Mountains, offer an ideal fieldlaboratory for geologic studies and researchby faculty and students. Note how theerosion of the steeply dipping formationsgive a false impression of folding.

years ago. The Paleozoic and Mesozoicsedimentary rocks, which were above thegneiss, "slid off the hill" and wereintricately folded. Davis presents evidencein favor of gravity-gliding from themountain rather than overthrusting fromthe basin. Dr. Davis is also using ERTSphotos in a photogeologic and fieldanalysis of macroscopic folds in theColorado tectonic province of Arizona.Tom Heidrick gave several talks onfr a cturing and diking in Laramideplutons, work which will add significantlyto our understanding of southwesterntectonics.

In his master's thesis, Joe Wilkins hasuse d in du ced-polarization (IP) andresistivity methods to locate the zone ofmeteorite particles at Meteor Crater atthe base of the impact breccia.

An aeromagnetic study of theColorado River delta area, Mexico by M.De la Fuente Duch has detected asp re a ding center which should beinvestigated for possible geothermalresources.

The Second Annual Geoscience DazeStudent Colloquium was held April10-11, 1974 with participation byapproximately one-fourth of the graduatestudents. Over half the papers presentedcovered some aspect of the geology ofArizona.

Talks on the mineralogy or petrologyof certain rocks in Arizona included theO'Leary Porphyry, the Red Cloud Mine,tuff rings, and the Monte CristoPegmatite. Katherine Bladh studied theO'Leary Peak volcanic dome of northernArizona and did some experimental work

on rapakivi texture (oligoclase rimmingsanidine). Gary M. Edson studied themineralogy of the Red Cloud Mine, YumaCounty with particular emphasis on thedistinctive, red-orange mulfenite crystals.

Daniel J. Lynch explained the originof tuff rings in multi-vent basalticvolcanic fields. John P. Mohon appliedthe geothermometer, which is based onSodium substitution for Potassium inmuscovite, to the Monte Cristo Pegmatitein Yavapai County.

Talks on structural geology includedgravity gliding, isostatic rebound, and theTexas lineament. Eric G. Frost, John P.Schloderer, and Dr. George H. Davisscrutinized folded gravity-glide sheets inSaguaro National Monument east ofTucson. R. Brett Liming analyzed thedeformation in the Martinez Ranch areaon the southeastern margin of the RinconMountains near Tucson. He questionsDrewes' (1973) interpretation thatLaramide thrust faulting moved thePaleozoic "block" 10 to 20 milesnortheast and suggests that the "block"moved south-southwest off the highRincon Mountains. John P. Schlodereralso questions previous thrust faultinginterpretations for the presence ofsedimentary and metasedimentary rocksin the Redington Pass area east of Tucsonand suggests folding resulted from gravitysliding along bedding planes. Monte M.Swan examined the Stockton Pass Faultwhich truncates the south end of thePinaleno Mountain Precambrian Gneisscomplex in Graham County. Heconcluded that the Stockton Pass Fault,which is expressed as a N.70o W. shearzone, is an element of the TexasLineament and that it demonstratesmajor Precambrian left-lateral wrenchfaulting as the origin of the Lineament.

Geophysical investigations in the Basinand Range Province of Arizona arediscussed by Carlos Aiken and Dr. JohnSumner. They have correlated theBouguer Gravity Anomaly Map ofArizona (West and Sumner, 1973) withthe Residual Aeromagnetic Map ofArizona (Sauck and Sumner, 1970).

A geochronological study is beingconducted by Robert B. Scarborough onthe vitric air-fall volcanic ashes which arefound in Pliocene valley fill sediments insouthern Arizona. Thus far, he hasrecognized two volcanic episodes. Oneepisode between 5 and 6 million yearsago produced at least 7 ash falls in thelower San Pedro Valley, Verde Valley,and lower Colorado River. A youngerepisode between 2 and 3 million yearsago produced at least 4 thin ash falls inthe upper San Pedro Valley and SulfurSprings Valley. Chemical studies suggestthat no more than 2 major sourcevolcanoes were responsible for all thesedeposits.


The age of rocks older than a few million years can be determined by measuring theradioactive rate of decay of the isotope rubidium-S7 to strontium-S7. The rUbidium-strontiumratio method is used for such problems as the age of porphyry copper deposits or of the ancientPrecambrian rocks of the Grand Canyon. The picture shows the electronic equipment in thegeochronological laboratory which is used in conjunction with a mass spectrometer to makesuch age determinations.

Economic geology was represented bypapers on alteration at the San Manuelore body by Jerry D. Davis and thesecondary dispersion of tungsten byRichard Frederickson, which have beendiscussed above. Other papers include thealteration assemblage at Esperanza byVerI L. Smith and strata-form sulfides atthe Copper Queen Mine by Ken Brook.Both the wall rock and the layered sulfideore at the Copper Queen Mine nearMayer, Yavapai County have undergonesimilar deformation. Therefore, KenBrook concludes that the sulfide bandswere present in the rock before thedeformation occurred.

M&G·ENG Continued

Undergraduate enrollments ingeological engineering have increasedrecently in the Department and jobopportunities and starting salaries forgraduates are excellent. Even though thisgrowth cannot be attributed entirely tothe energy crisis, that phenomenonfocused attention on the importance andchallenges of applying geology in themineral and construction industries aswell as in environmental and urbanproblems - a key element when a youngman or woman is choosing a career.

Spurred on by larger enrollments andexpanded research and teachingprograms, the Department has embarkedon a number of new activities. Simulationof actual problems and fieldcharacterisitics has played a large role inthe teaching methods as indicated in thefollowing selected sketches, illustrating


George Eliopulos examined thegeology of the Mineral Mountain area,Washington County, Utah near theeastern margin of the Basin and RangeProvince just north of Arizona. TomAndrews summarized the structural andigenous geology of the Troy miningdistrict in the central Dripping SpringMountains southeast of Ray, Arizona.

Jeffrey A. Boyer investigated thehydrogeology of the Carefree Ranch areanorth of Scottsdale to determine thegroundwater availability. Frank A.Packard discussed some discontinuousstreams near Tucson and proposed atheoretical model for their formation.

how students may learn to adaptthemselves to real-life situations that theymay meet in their later professional years.

Exploration is the first step in findingnew mineral resources. With the rapiddepletion of known mineral reserves andthe increasing difficulties and costs ofdiscovery of new sources, the geologicalengineer needs all the scientific training,imagination, logic, and experience he canmuster.

Dr. W. C. Peters offers the followingexample of a problem in the search forore and the design of an explorationprogram.

The Casi Cuatrocientos mountainrange rises in rugged isolation above thedesert alluvium in Geronimo County:6000 square miles of relatively unmappedand unexplored Mesozoic rocks withreported occurrences of lead-zinc districtsin similar geologic terrain.

Dec. 1974

Can a group of students with thebackground provided by the University ofArizona's courses in geoscienceexploration, and mining find a hidde~orebody in the Casi CuatrocientosMountains? A course in the departmentof mining and geological engineering,using a simulation gaming techniqueadopted from management training, letsthem try. It provides students with alearning experience to bridge the gapbetween textbooks and the "real world. "Real world exploration conditions aresimulated: budgets, costs, time schedules,decisions, unforeseen developments, andcompetition between groups of studentstrying to find the same orebody.

The model for the Casi CuatrocientosMountains is real, but it exists half-wayaround the earth from Arizona. None ofthe students have had the prior advantageof seeing it, so all begin on an equalfooting.

In order to give one of the recentsimulation games a southwestern flavorand to hide the identity of the modeluntil the final "moment of truth," twomining districts, Touissit-Bou Beker andAouli in Morocco, became theTarantula-Big Bug and Anteater districts,Arizona. The towns of Matarka, Tissaf,and Mahirisa became Mad Dog, TwoGuns, and Mesa Ridge on the borders ofthe Casi Cuatrocientos Mountains.Nothing else was changed; the terrain, itsgeological, geophysical, and geochemicalch ara c teristics, and its Arizona-likeclimate remained as in Morocco.

Exploration teams, each with two orthree students, submit weeklyexploration plans, with each weekrepresenting two months in the field. Theresults of exploration - field geologicmaps, geochemical data, geophysicalprofiles, and drillhole logs - are furnishedby the professor so that each team canargue and anguish over them as a basis forthe next plan.

Interest and competition mount witheach step as the budgeted funds forexploration shrink and the unexploredarea is reduced to anomalies and targets.

A stream sediment sampling programmay disclose a minor drainage area withhigher lead content than elsewhere, butsubsequent rock sampling shows nospecific anomalies. Another look at thereconnaissance geologic map and thepattern suggests a broad, anticlinalstructure. Look once more at theaeromagnetic map and a basement upliftis indicated. Now try ground magneticsfor stronger indications. Inducedpolarization is tried; it gives a significantresponse, but not where expected. Trychanging the assumptions (the tentativeexploration model). Back to moredetailed geologic mapping, and thelimestone plotted on reconnaissance mapsis now seen to contain a reef member.

el

'where are the othercOI'npeting teams working? Is there time

a drillhole? What will the budget

One team may have decided that theywill drill some holes for stratigraphicinformation. Suppose that some of theholes encounter no bedrock and one holeencounters unexpected mineralization.Shall we deepen some of the holes, drilladditional holes, or continue with theoriginal schedule? The clock is ticking,the budgeted funds are shrinking. This isas close to the "real world" as a studentcan get while still in the collegelaboratOl)'.

Meanwhile, back at the source oforiginal data, the professor doles out theinformation as it is "bought" frombudget funds on a realistic cost basis.Nothing more is supplied until thenext-to-final course meeting when theorebody is unveiled. Then, winners andlosers exchange congratulations andcommiserations.

A t the final meeting in the coursethere is a critique, and a comparisonbetween each team's approach and theprogram used in the discovery fromwhich the original information was

The studen ts now have aninkling of how they will be called upon tomake professional decisions. This time itwas a simulation, the next time will be"for real" in a world pressed by mineralshortage.

A part of the answer to problems ofmineral shortage lies with exploration;exploration based on science, stimulatedby imagination, guided by logic, andmade practical by experience. Thegeological engineering course at theUniversity of Arizona in "simulationgaming in exploration" should helpstudents become tomorrow's engineerswho will have to find the answer.

Another important aspect of mininggeology is mineral economics. In order togreatly expand our capabilities in thelatter field, we are fortunate to have Dr.DeVerle Harris join our faculty tocontinue his research and teaching inmin era I e con 0 m i cs, e sp e ci allyquantitative exploration models andstatistical methods for mineral resourceappraisal.

Most civil engineering projects requirethe acquisition, interpretation, and use ofgeological knowledge concerning thematerials in the Earth's crust. This branchof geology is called geotechnics. Forstudents oriented more towardsgeotechnics than mineral exploration,simulation problems, similar to thefollowing, are given by Dr. Charles Glass.Dr. Glass' main fields of teaching andresearch are earthquake engineering,engineering geology, and photogeology.

The Pima Gas and Electric Companyhas contacted the firm of Glass-Peters and

FIELDNOTES

Associates to make a feasibility study fortwin pressure tunnels to be constructed inan area of northern Arizona. ApreliminOl)' outcrop geologic map isavailable from the client which shmv apre do min ant conglomerate-sandstoneshale facies with rather peculiartopographic relief Can a group ofstudents design an exploration programto locate the geologic hazards in the areaand based on their conclusions makerecommendations regarding design? Canthey do it within a fixed budget? Verticaland angled boreholes and open and closedtrenching will be the exploration tools,and a computer will provide the cold,impartial means by which they get theirresults. A deep hole in the hardconglomerate may deplete three-quartersof one student's budget. Another studentspends $18,000 ofhis allotted $20,000 ina shotgun pattern and misses then u m erous wide fault zones slicingthrough the area. Planning, carefulplotting, and geologic and engineeringskill payoff when the students arrive attheir final tunnel alignment andpreliminary design factors. Not only isthe student harried by the whims of thegeologic environment and the pressure ofa tigh t deadline and budget, but before hecan spend the money he must presentorally the logic behind his explorationprogram. After his geologic map andcross-sections are complete, he mustmake an oral presentation of his reportand recommendations to a sometimesskeptical group of professors and studentsrepresenting the interests of the client.

Yes, in the "GeotechnicalInvestigations" course at the Universityof Arizona, students make mistakes,squander clients' money, and learn howhard and embarrassing it is to try toexplain a poor exploration program orallyin front of a group of professionals.Brutal? Perhaps. But, better here thanlater in th eir professional career.

Ge omechanics is another subjecttaught in the Department and one inwhich active research is being carriedforward. This branch of geology dealswith the structural response of naturalmaterials to deformation or changes dueto the application of stress or strain.Teaching in this field are Dr. R. D. Call, apart-time lecturer specializing in slopestability, and graduate student D.Nichols, covering underground openings.

A great deal of research eff01:t in theDepartment has been directed toward theplanning and development of open-pitmines. Dr. Young Kim, specializing ingeostatistics and computer applications, isinvolved in two interesting projectsrelated to the evaluation of surfacemining ventures. One project is directedtoward verifying Matheron geostatisticalconcepts (a specialized statisticalinterpretation) on a large Arizona

p orp hyry copper deposit. Graduatestudent Pete Knudsen is completing hismaster's degree on this project.

The second study by Dr. Kim is a partof a major project, funded by theCanadian government, concerned withproducing a Pit Slope Design Manual. Ourcontribution to this effort is to develop ageneralized model for the financialevaluation of altering the pit slope anglein a surface mining operation. Theincentive for mining at a steeper slope isobvious - less waste or unprofitablematerial needs to be mined to extract theore. For large, deep open-pit coppermines, an increase of a few degrees in theslope angle can literally mean the savingof millions of dollars.

However, steeper slopes mean that afailure, such as a slide, is more likely tooccur with the resulting expense ofcleanup or perhaps even suspended oreproduction and equipment damage. Thus,there are clearly costs as well as benefitsassociated with steeper pit slopes. Ourobjective is to find the slope angle whichwill produce the highest expected netresults.

First, there is the problem of definingthe cost of a failure. Cleanup costs maybe straightforward, but what about thecosts of lost production or lost ore?Secondly, slope failures clearly are notdependent solely on the slope angle. Alarge number of other parameters, largelygeologic such as the characteristics of therock or alluvium, moisture content, andlocal structure and slope heights, also arerelevant. One slope may stand very wellat 60 degrees while another will fail at 35degrees.

The first problem of cost of failure hasbeen attacked by defining a number offailure models from which the programuser may select the likely failure modesfor his mine. Alternatively, he can specifya unique failure model with associatedcosts if he wishes to do so. The secondproblem of other factors has beenovercome by adopting the "probability offailure" concept. Here, the geomechanicsspecialist will estimate the likelihood offailure under varying conditions for eachslope as a function of slope angle andslope height. Then by using Monte Carlosampling methods, a procedure in whichrandom figures are used to approximatethe solution to an intractable problem,we can simulate the mining of the depositmany times to find a probabilitydistribution of possible net benefits.

The value of the study is themethodology involved rather than anyspecific results. Although slope angle is acritical vatiable in the financial analysis ofsurface mining ventures, there aredivergent operating philv~v~'H.L"~

regarding slope angles. Our work att:enlp1~s

to provide aelements pertinent

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Volume 4 NO.4 Dec. 1974State of Arizona

Governor •••••••••• Hon. Jack WilliamsUniversity of Arizona

President ••••••••••••John P. SchaeferArizona Bureau of Mines

Director ••••••••••• William H. DresherEditor., • • • . • • • • • •• Stanton B. Keith

ARIZONA BUREAU OF MINESTHE UNIVERSITY OF ARIZONA

TUCSON. ARIZONA 85721

THE UNIVERSITY OF ARIZONAARIZONA BUREAU OF MINES

TUCSON, ARIZONA 85721RETURN POSTAGE GUARANTEED

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