ARIZONAGEOLOGICAL SURVEY

Information toArizonans since 1889

Headline News

Figure 1. Damage caused byfloodill8 of the Rillito River ill TUCSOIl, October1983. Photo provided by Peter L. Kresall

see HEADUNE NEWS, page 2

volcanic ash beds, andvolcanic cinder cones areevidence of relativelyyoung volcanic eruptions.Although there is noindication that a volcaniceruption in Arizona isimminent, we might haveto shovel ash if an erup­tion occurs in lammothLake, California when thewinds are blowing ourway. In portions oft-Iaricopa, Pinal, Pima,and Cochise Counties,land subsidence causedby overpumping ground­water will cause propertydamage as developmentcontinues.

Even those who

in southern Arizona. Ifthe concept of the 100­year flood was valid, therewould have been about10,000 of them during thelast million years alone.

Although flooding isArizona's leading naturalhazard, it's not the onlyone. Faulting and volcan­ism ha\'e also played amajor role in shaping theState. Rock units through­out the State hm'e beendisplaced by faults, mostof which have long beeninactive. Some faults havebeen active in the not-too­distant geologic past,however, and havepotential to generate largeearthquakes. Lava flowsthat cooled as basalt,

Larry D. Fellows, DirectorArizona Geological Surrey

Geologic processes,including flooding,earthquakes, and volcaniceruptions, have beenmajor news stories thisyear. During July andAugust alone, flooding inArizona caused a trainderailment near Kingman,evacuation of the \'illageof Supai near the GrandCanyon, drowning ofeleven hikers in AntelopeCanyon (a slot canyonnear Page) and drowningof eight people who weretlying to enter the U.S.illegally through a drain­age tunnel in Douglas.Meteorologists now adviseu . that the developing EI

ino system appears to bethe strongest in at leastthe last 50 years. The1983 El 1110 was associ­ated with extensiveflooding in Arizona, whichresulted in 13 deaths andabout $300 million dam­age statewide (figure n.

Any clJy wash inArizona can become araging torrent if substan­tial amounts of rain fall ona drainage basin in a shortperiod of time. In theearly 1980s back-to-back100-year floods occurred

• Provide informationabout Arizona geology

• Map and describebedrock andsurficial geology

• Map and characterizemineral andene~y resources

• Investigate geologichazards and limitations

• Prepare and publishgeologic mapsand reports

• Maintain databasesand files

• Maintain geology library

• Maintain rock cuttingsand core repository

• Provide administrativeand staff support for Oiland Gas ConservationCommission

A.R.S. § 27·152

MISSION

To provide unbiasedinformation to the pub­lic to enhance under­standing of Arizona'sgeologic frameworkand support prudentmanagement and useof land, water, mineral,and energy resources.

Headline News (continued from page 1)

ARIZONA'S MINES LEAD NATION

GOVERNORJANE DEE HULL

ARIZONAGEOLOGICAL

SURVEY

Director and State GeologistLarry D Fellows, Ph.D.

PublicationsRose Ellen McDonnell

Peter F. CorraoMary E RedmonMary E Pasborg

Earth ScienceInformation Center

Heather C. Thrall

Geology LibraryThomas G McGarvin

Arizona GeologicInformation System

Richard A. Trapp

Center for Land-Subsidence& Earth-Fissure Information

Robin Frisch-Gleason

Mapping and InvestigationsJon E. Spencer, Ph.D

Philip A Pearthree. Ph.D.Stephen M. Richard, PhD.Charles A. Ferguson, PhD.

Wyatt G. Gilbert, PhDRaymond C. HarrisJeanne E. KlawonSean M. Kneale

Robert S Leighty Ph DSteven J Skotnicki

Oil and GasSteven L Rauzi

LOCATIONArizona Geological Survey

416 W. Congress, Suite 100Tucson, AZ 85701

(520) 770-3500

Web Address:http://www.azgs.state.az.us

1Jt.",~ndl1(Jl. \.'ut

Peter F. Corrao

Cllr\rt~hl 14~-

by Ihl' An.llln.l <....Cll]ogh.aIO"une

PUIlIt I(mrl 1duJpaper

Arizona GeologyFall 1997 • Page 2

venture out to observeArizona's spectaculargeology are not immunefrom risk. In late August, atourist fell 800 feet to herdeath at Toroweep Point inthe Grand Canyon, thefourth fatal fall this year.On average, six people diethat way every year.

Yuma has the highestealthquake risk of anyplace in Arizona because ofcloseness to active faults insouthern California. ChinoValley, the Flagstaff andGrand Canyon areas, andsoutheastern Arizona havemoderate hazard. In May1887, movement along afault 30 miles southeast ofDouglas generated anearthquake that causeddeaths and propeltydamage in Sonora anddamage throughout south­eastern Arizona. A compa­rable quake today wouldcause even more damage,because many more peoplenow live in the area.

Level of risk fromgeologic processes variesfrom state to state. On thebasis of frequency andmagnitude of historicearthquakes, risk is greaterin California, _ evada, andUtah than in Arizona.Arizona's earthquake risk ismore difficult to assessbecause the known faultshave longer inrervalsbetween times of mO\'e­ment. We could be in for amajor surprise. \Xril! we beprepared?

After fount Pinatuboerupted in the Phillippinesin 1991, we printed a guestcommentary by CharlesOsgood, CBS ews, inArizona Geology (\'. 21, no.3). His conclusion is as

appropriate today as it wasthen: "It's difficult for us,whose lives are so short, to~vorry about something thatonly happens every fewcenturies or so... Butbecause there hasn't beenan eruption in a givenpbce for a while, we get tothinking, or at least pre­tending, that it isn't goingto happen ... We go ontaking our chances, build­ing our cities, planning ourfutures, as if only thethings that h3\ e happenedlately -were -what we haveto worry about. The lessonof history is that, for betteror for worse, just becausesomething hasn't happenedin a long time, doesn'tmean it isn't going tohappen no"-."

The Arizona Legislatureassigned responsibility fordescribing and characteriz­ing the State's geologichazards and limitations tothe Arizona GeologicalSUITer (AZGS). AZGS

Arizona led the nationin \',due of commoditiesmined in 1996, accord­ing to a national studyreleased by the NationalMining Association. Allbut a small percentageof Arizona's mine outputis copper. Value ofminerals mined inArizona was $4.98billion, which is 8.3percent of the totaloutput of the Tation.Arizona was followed byWest Virginia. Kentucky,j evada, and California.

geologists have conductedinvestigations, preparedbedrock and surficialgeologic maps, compileddata, and released publica­tions on channel migrationon alluvial fans, paleofloodhydrology, river channelmorphology, young faults,earthquakes, and landsubsidence and earthfissures. The AZGS sellsmore than 70 publicationsthat describe geologicprocesses in Arizona, 3'5 ofwhich are listed in a freebrochure, Geologic HazardPublications. The bro­chure includes prices andordering information.Many detailed maps ofbedrock and surficialgeology ha\'e also beenreleased. AZGEOBIB, the12,000-citation biblio­graphjc database, is key­worded and searchable.Check out the wealth ofreports, maps, data, andrelated information that areavailable. They're yours.

Mining employed 12,600Arizonans. Mining andmining-related employ­ment, including trade,service, and governmentjobs, was about 73,000.J early 137,000 jobs inArizona were directlyand indirectly related tomining.

I'I'Jining's directeconomic impact inArizona in 1996 was $2.3hill ion. The combineddirect and indirectimpact was $13.7 hillion.

New PublicationsThe Arizona Geological

Survey (AZGS) released thefollowing reports and mapssince May 1997:

National Geologic Map­ping Program: The fivemaps listed below depictsurficial and bedrockgeology. The area mappedincludes the north side ofthe Superstition Mountains,southwestern MazatzalIV!ountains, and the areaalong State Highway 87between Sycamore Creekand Stewart Mountain.

(1) Geologic map of theAdams Mesa Quadrangle,Maricopa County,Arizona: S. J. Skotnickiand R. S. Leighty, 1997,Arizona Geological SUlyeyOpen-File Report 97-10(Pub. number OFR 97-10),13 p., scale 1:2,"*,000. $5.00

(2) Geologic map of theMine Mountain Quad­rangle, Maricopa andGila Counties, Arizona:S. J. Skotnicki and R. S.Leighty, 1997, ArizonaGeological Survey Open­File Report 97-11 (Pub.number OFR 97-11), 11 p.,scale 1:2,+,000. $5.00

(3) Geologic map of theStewart Mountain Quad­rangle, Maricopa County,Arizona: S. J. Skotnickiand R. S. Leighty, 1997,Arizona Geological SurveyOpen-File Report 97-12(Pub. number OFR 97-12),19 p., scale 1:2,"*,000. $5.00

(4) Geology of theMormon Flat DamQuadrangle, MaricopaCounty, Arizona:C. \. Ferguson and WI. G.

Gilbert, 1997, ArizonaGeological Survey Open­File Report 97-14 (Pub.number OFR 97-1-t), 28 p.,3 sheets, scale 1:24,000.$10.00

(5) Geology of the HorseMesa Dam Quadrangle,Maricopa and GilaCounties, Arizona:WI. G. Gilbert and C. A.Ferguson, 1997, ArizonaGeological Survey Open­File Report 97-15 (Pub.number OFR 97-15), 14 p.,scale 1:2"1,000. $6.00

National Geologic Map­ping Program and theEnvironmental Protec­tion Agency Indoor­Radon Program: The twomaps listed below \\'erefunded by these Federalprograms and the AZGS.Large areas of Quaternarysurficial deposits andProterozoic bedrock arepresent, in addition to abelt of tilted Tertiarysediment<lIY and volcanicrocks. The latter includetuffaceous marl withelevated levels of uranium.

(1) Geologic map of theCave Creek Quadrangle,Maricopa County,Arizona: R. S. Leighty,S. J. Skotnicki, and P. A.Pearthree, 1997, ArizonaGeological Survey Open­File Report 97-1 (Pub.number OFR 9-'-1), 38 p., 2sheets, scales 1:2,"*,000 and1:12,000. $12.00

(2) Geologic map of theWildcat Hill Quadrangle,Maricopa County, Ari­zona: S. J. Skotnicki, R. S.Leighty, and P. A.Pearthree, 1997, Arizona

Geological Survey Open­File Repolt 97-2 (Pub.number OFR 97-2), 17 p.,scale l:2'!,000. $5.00

Digital geologic maps:The m'o maps listed beloware digital versions ofpreviously released maps.The geology is presented infour separate files orcoverages: 1) contacts andfaults, 2) other linearfeatures (dikes, veins), 3)structural data, and -t)volcanic centers (degener­ate areas). Data are in ArcInfo export files (.eOO).Other data files include anESRI shapefile that showssource maps u'ied in theoriginal compilation andxBase (.dbf) tables withdescriptions of the rockunits and suggested colorsfor displaying the map. Astandard metadata text filecontains a completedescription of the data set.A copy of Open-File Report97-5, which describes thedatabase structure andfeature coding used, isincluded as a computer file(MS Wlord and HUlL).

1) Digital representationof the geological map ofthe Salome 30' x 60'Quadrangle, west-centralArizona: S. M. Richard,]. E. Spencer, and S. ].Reynolds; J. P. Thieme,digitizer; and S. J\I. Richard,editor, 1997, ArizonaGeological Survey DigitalInformation Series 6,\'ersion 1.1 (Pub. numberDI-6), 2 HD disks, 3 p.$30.00

see NEW PUBliCATIONS, page 4

How toOrder Them

You may purchasepublications at the AZGSoffice or by mail. Addressmail orders to AZGSPublications, 416 W.Congress St., Suite 100,Tucson, AZ 85701.Orders are shipped byUPS, which requires astreet address for deliv­ery. All mail orders mustbe prepaid by a check ormoney order payable inU.S. dollars to the ArizonaGeological Surveyor byMaster Card or VISA. Donot send cash. Add 7%sales tax to the publica­tion cost for orderspurchased or mailed inArizona. Order bypublication number andadd these shipping andhandling charges to yourtotal order:

Shipping &. HandlingCHARGESIn lhe Unileu Slale"

Less lh3n $1.01, add . I.on1.01- 10.00. add 3.00

10.01- 20.00, add -I.SO20.01- 30.00, aud ').7').30.01- -10.00, aud 6.')0-10.01- ')O.UU, aud R.UU50.01- 100.00, aud 10.2';O\er 100.00, add 12""

Other countries,request price quolation.

Shipping and handlingcharges include insur­ance. For rolled maps,add $1.00 for a mailingtube.

If you purchase Open­File Reports, ContributedMaps, or ContributedReports at the AZGSoffice, allow up to twodays for photocopying.

Arizona GeologyPage 3 • Fall 1997

DATA • INVESTIGATIONS • INFORMATION • SERVICE

NEW PUBUCATIONS,from page 3

2) Digital representationof the geological map ofthe Little Hom Moun­tains 30' x 60' Quad­rangle, southwesternArizona: ]. E. Spencer,compiler; K. 1\1. Korrochand]. P. Thieme, digitizers;and S. M. Richard, editor,1997, Arizona GeologicalSurvey Digital InformationSeries 7, version 1.1 (Pub.number 01-7), 3 HD disks,3 p. $30.00

Geologic map of Arizona,GIS database, v1.0:S. M. Richard, compiler,Arizona Geological SurveyDigital Information Serie 8(Pub. number DI-8), 2 HDdisks. $30.00

This is a digital versionof AZGS lap 26, scale1:1,000,000. Data from theoriginal version have beentranslated into Arc. 'Info andedited to improve accuracy.

linor revisions have beenmade to the classificationof rock units. Because ofthe histolY of this data set,

faults and contacts are inseparate layers (coverages).Outlines of regions ofMesozoic metamorphismand TertialY mylonitization,shown on Map 26, areincluded in a separatelayer. These geographicdata are in Arc/Info exportformat (eOO). Tablescontaining descriptions ofrock units and suggestedcolors for displaying themap are in xBa e (dbf)formal. An index of sourcemaps used in the originalcompilation is included inan ESRI shapefile, withbibliographic citations inan associated xBase (db£)table.

Geologic maps of partsof the Gila Bend Moun­tains near Woolsey Peakand Signal Mountain:]. E. Spencer and W. G.Gilbert, 1997, ArizonaGeological Survey Open­File Report 97-8 (Pub.number OFR 97-8), scalel:2't,000. $2.00

These geologic mapsclarify the nature of lower

Miocene rocks and struc­tures in the Gila BendMountains. Volcaniclandforms and igneousintrusion played a signifi­cant role in causing basinformation and disruptingbasin-filling sediments.

An unconventional,multidisciplinary ap­proach to evaluating themagnitude and fre­quency of flash floods insmall desert watersheds:P. K. House, 1997, ArizonaGeological Survey Open­File Repon 97-9 (Pub.number OFR 97-9), 61 p.$10.00

The author used tech­niques of paleofloodhydrology, air photoanalysis, and historicalresearch, together withsparse hydrological andmeteorological data, tocompile a regional floodchronology. In the ninesmall drainage basinsstudied, fla h floods haveoccurred over more thanthe last 1,200 years.

Bibliography of uranium­and copper-bearingbreccia pipes on or nearthe Colorado Plateau ofArizona: R. A. Trapp, 1997,Arizona Geological SurveyOpen-File Repolt 97-13(Pub. number OFR 97-13),11 p. $3.00

This is a list of 205citations from AZGEOBIB,a computerized, annotatedbibliographic database withmore than 12,000 citationson the geology of Arizona.

Geologic map of theeastern Plomosa Passarea, northern PlomosaMountains, La PazCounty, Arizona:T. R. Steinke, 1997, ArizonaGeological SUf\'ey Contrib­uted lap 97-A (Pub.number C I 97-A), scale1:3,570. $3.00

This geologic mapre\'eals complex deforma­tion of Paleozoic and1\lesozoic rocks producedby multiple episodes ofMesozoic deformation.

Arizona Geological Survey416 West Congress, Suite 100

Tucson, AZ 85701(520) 770-3500

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