State of Arizona Bureau of Geology and Mineral Technology Geologic Investigation Series Map GI-2-C A 1300 lOOO D 1600 l 1300 1000 G 1300 1 000 700 GEOLOGIC CROSS SECTIONS OF PAPAGO PARK PEDIMENT TEMPE QUADRANGLE, MARICOPA COUNTY, ARIZONA 1'Z'W' INTRODUCTORY STATEMENT Papago Park Pediment is tile erosional remnant of an IIptluowfl fault block which has been cut by several sma ll er fault!;, Since me time of uplift, has recluced the origirkll upland mass to a number of srna ll inselbergs protruding above II relatively gently sloping surfllce, T he bod rock surface is locally covcrod ov up to 20 feel 16 m) of ca ti chified colluvium·a ll uvium, Thi s deposit has accumulated in re3Ponse to the oggrading va llev·fill alluvium, I" r asponsa to a change in the regimen of the Salt Rive r, tributary streams draining the pediment have incised daap channals into the calichified colluvium· alluvium, locally exposi ng bedrock. This colluvium·alluvium is though t to be as much as 5 million years uld dua 10 tha thickness and induration of the calich e. Therefore the pediment illiel! must be lNen older for it to ba rtot(lur:ad to a nsarly level surface before the younger deposi t formed ebove it. GEOLOGIC HISTORY Th e oldest rock exposed at Papago Park Pediment is Precambrian metarhyolit e, produced from low.grade metamorphism of rl vo( i tl c ashes and lava flows . Sirnililr rocks occur in the Phoenix Mountains and McDuwell Mountains (Taliesin Quartzite) to the nonh and nonheast, where they ala interbedded with metasedimenliHY rocks probably deposited in shallow, sh ift ing seas. The meta rhyolite is intruded by two distinctly different granites; the relationship between the two granites is not evident within the Tempe Quadrangl e. Tovrea Granite, a gray granite ri ch in qu artl and biotite. is similar in composition to pluto rr s found elsewhere in ArI:tOna wh ich yield ages of 1,650 to 1,7HO million years old. Game loock Granit e. u pink gr1l llito rich in microcline and perthite with less than 10 % mafic minomls, was probably emplaced at the same time es similar granitas found at Camelba ck Mountein , McDowell Mountpins. and Usery Mountains, which yield ages of 1,350 to 1,460 million years old. Both granites aoo the meta rhyolite are intruded by basatt and aplite dikes and veins An un conf ormity exists between the eroded Precambrian rocks and the mid- Tmti ary red beds. No rocks of nor MeSIJwic Eras are found in tha Tpmpe Quadrangle or the SUrrounding ureil. Some time bef ore the depo9ltion of the red beds, tho metarhyolite an d Gameloock Grani te were subjected to in· tense shearing and cataclastisi s. . During t he mid·Tertiary time, rapid uplift end erosion of thc Precambrian rocks resulttld in the depositiun of rcd bo-ds, including fanglomeratas, sandstones, and Eal1y mid-Tertiary volcanic eruptions produced ash Ihat was mtransported and deposited along with channel sands and weathered rock debris, and was preserved in scatlmoo Io calitill5 (t he Basa( Membm of t he CatTMI ls Head Formation). As the highlands rose. alluvial fans formed at the base 01 the mountain fro nt, and coarse, angular, un- :;ort ed deposits accumulated in me proximal fan environment. A voriation in sediment so urce is indicated by a local vuriution in the composition of the clasts and reflects separate lobes 01 fans that coolooce w ith ann ovorlin U"[] 1I.mlher. The proximal fa(; i a£ are vary (;0'111"$0 and 9lrEltifk'd, hevino orioinel ed as to lus, landslides, and mud flows (Zoo Brtlccia, Barnes Butte Breccia, and Stadium Breccia members of the Came ls Head For m<:rtion). On th e mid·fan, watarlaid deposits were in terbedded w ith debris f low deposits originating from the reworking of tha The deposits are finer·gralned, with be tter sortin g, and stratificati on (Papago Park Member). Epherme r<:r l stnlarrl>; reworked the deposits of the prox:· i",al and mid-fan, and carried th ese sediments to t he distal ends. Distal facies (lre line/'grained, well stratified <lnd well sortad namfl8 beds). Local volcanism, probably in the form of fissure eruptions, I)ro· duced ashes and lavas r(lnging in composition from basalt to rhyodacite, which overlie and are interbedd· ed with the red beds. Andesite of Tempo Butte has a radiomatric date of 17 .6 ± 0.4 million years (Scar· borough and Wil t, 1979). Basa lt sills (Drosendahl. 1900' Itermed andesite by S(:;)rborough [1981]) in the Camels He<ld rormat ion al Mt. McQowe ll, 16 miles 1281::m) east of Tempe have dates of 18.7 to 17.7 million ycars (Scarborough, 1981). The modern day physiography of the Basin and Range Province resulted from tectonic el/enlli t hat occurred du ring the last 17 million years. The Basin and Range di:;lur h;JrrCB is characterized by generally vartical movement along steep normal faults. The feulting is related to deep-seated r)xtension resu!ting in the thirmillg and fragmentation of the eanh's crust. The sedimentary and volcanic rocks have beon stoep' Iy tHted to their present striking northwest ·southeast w it h an average dip of 45°SW. Faulting is necessary to expl ain repetition of r(l(:k se quence:!, and you" ger rocks dipping toward older onas (see cross·sections!. A nu mber of faults ara shown on the geol ogic map. The evid ence for thll eJlistenca of such fa ults is strong, bu t nOlle are dirllClly observabl e. The evidence is ; (lithe rotation of the b€dd ing uf the Carnels Head Formation into vuriuble and stoap dip, and (21 the truncat ion of t he Camels Head Formation along relativelV abrupt and straight lines. A ll of I hesela ults arc interpreted to be high·angla dip·sl ip fau lts. Addi· tional support for this Interpretation comes from the myriad 01 sll,a ll faults with this orientation and (iisplacement that are observed within many of t he buttes. The buri ed fault shown near McO(M'eU and 52nd Street i:; tmsed on the resuilli of drilling interpreted bV AtkinsOfl and Hay (1983). It too is interproted to be a high·angle fault. Papago Park Pediment is probably bounded by faults to me east and west, for me depth to bedrock rapidly increases to either side. The pediment, togclfmf with Tempe Butte, Bell Butta, and Twin Buttes, forms part of a discont inuous bedrock link across the Phoenix: Basin be tween South Mountains, and Carm;ilJuck and Phoenix Mountains to the nort h. Erosion of these and other bedrock highklnds has contributed more t h<:rn 10,000 feet 13300 m) of all uvium to fill the adjoining basins. SELECTED REFERENCES Atkinson, D. E.. and Hey. SM., 1963. Preliminary report of MoluffJla Chemi cal Lea k Project, Saction 2: Geology: in Gutlerrez· ra lmenbert. Inc., 1983, Preliminary report of Motorola Chamical Leak Proj· ect; Phoenix, p. II·' . 11·35. with Appendix A, 42 p. Christenson, G. E., Welsct), 0, G" (lnd Puwb, T. L., 1978, Em'ironmental geology of the McDowa ll Mountain ar(;!a, Maricopa County, Ariwna: Ariwna Bureau of Geolo!JV und Mineral Technology. Geologic InveSligation Series. GI-I ·A, 1 ;24.000. Cordy, G, E.. Holway, J. V., and Pilwll, T. L, 1977, E nllifOnmenta( grrology of the Paradise Valley Qued- ranllle, Mmicor.a County, Arizona: Tempe, Arizona, unpublished folio of maps prepared for tha Ci ty 01 Scutllidala. 14 sheet s, 1:24,(XX). Cordy, G. E., and T. L., 1978, Geology of the west end of Camelback Mountain, PhoeniK. Ari· zona: Geologica( Society of America. Abstracts with programs, 1978 Cordilleran Sacti on meeting, volume 10, "umb!!r 3, p. 100. Damon, P. E., Shafiqullah. M., and Lynch, D. J., 1984. Late Cenozoic landscape development in the Basin and Range Province of Arizona, ifl Smiley, T. L.. Nations, J. D .. Pewi!, T. L., and Schefer, .1. P., Landseapes of Arizona: the goologic story: Tucson, Arizona, University of Ar iz ona Prsss, p. 175-206. Orosendah(, J. K .. 1987, Environmental gao(ogy of tile Rio Salado Development District, eastern part unpublished Master of Seicnca thesis, A ri zona State University, Reynolds, S. J .. 1985. Grrology of the South Mountains, CCf1ttil i Arizona Bureau of Geology and Mineral Technology, Builetln 195, 61 p. Scarborough, R. B,. 1001, Reconnaissance geol ogy; Goldfield and Northern Superstition Mountains; Ari7.olla Bumau of Geology and Mineral Technology, Fieldnotes, volume 11, number 4, p. 6·10. Scarborough, R. B.. and Wilt, J. C., 1979, A study of uranium rovorabili ty of Conozoic sedimentary rocks, Basin and Range Province. Pan I: United States Geological Survey Open·f ile Report 79-1429.100 p. Schulten, C. S., 1979, Environmental geology 01 thc Tempo Quadr.;Jngle, Maricopa Cou"ty, Ari7.0na: unpublished Master of Science thesis, Arizonn Sla le Un ivcrsily, 101 p. Spearing, D. R., 1974, Summary sheels of sedimental"'l deposits wit h bibliographies - AUuvial fan de· posits. sheet 1: Geologica l S(I(:iety of America, 7 sheets. Stucklcss. J. S ., and Naesar, C. W., 1972, Rh·Sr and fission-track age datarminations in the Precam· brian pluton ic basement around the Superstition volcanic field, Arizonu: United Statl:!s Geological Survey Professional Paper BOO·B. p. BI91 ·BI94. Troy L. PeW£! Cathy S. Wellendorf James T. Bales Department of Geology Arizona State University 1986 Prepared in cooperation with the cities of Tempe, Scottsdale, and Phoenix, and the Arizona State Land Department SALT RIVER SAND AN D GRAVEl - Moderately to well sorted and well stratified, unconsolidat ed sand and gravel, locally interbedded with sill; ex hibits cut·and: fill structures, lent icular oorldinn , palall ol and cross·strat il ica tiOf1, and imbrication 01 cl(lsts. Clasts are well rounded , 2 to 12 in . (5 to 30 cml in diameter, and consist of Teniary volcanic rocks (36.3%), Precambrian meta sedimentary end metevok:anic rocks 148,4%1. and Precambrian granitic rocks 115,3%), Osg - modem channal deposits, no ca liche·. Qsgm (cross SEct ions only) - sand and gravel of the Mesa Terrace, strongly developed caliche. EXTREMELY FINE ALLUVIUM - GraV to tan. moderately·well soned, well stratified, sandy sHt. containing lew to no clasts, avel1lgin!l25% s<:rnd, and 75% sill and day . Qefm - moderately· to strongly·ca (i chified 91lt over Mesa Terrace grallef. Qofl - weaklV' to non· ca (ichified silt over Leh; Terrace gravfI!. Qefb - non· calichifred silt over bedroc k. VERY FINE ALLUVIUM - Tan to brown, moderately sorted, moderately·well st ra tif ie d, weakly to mod· erately calichified, gravelly !Sandy silt , averaging 10% gravel, with subangu lar to subrounded clasts general( y n-ot exceeding 1/2 in. (1.3 cm), 35% sand, and 5&% silt and clay. Clasts composed largely of grus and granitic Imgment s. FINE ALLUV IUM - Gray to tan. moderately soned, moderately stratified, weakly to moo'eratelv-caliehified, gravelly sandy silt, averaging 20% graval, with subangullt r to subrounded granitic clasts, genera((y not exceeding 1)1. in . (3.B cm) , 4D% sand, and 40% silt and day. SLOPE COLLUVIUM - Gray, poorly sorted, strongly·calichified t alus on l ower bedrock slopes. Composed of angular blucks, 1/2 to 8 il1. (1.3 to 20 cm) in diameter, matrix of silt and rock fraglTlEl nts. PEDIMENT COLLUVI UM·ALLUVI UM - Gray towhita, verypool1y so ned and stratified, strongly·calichilied debris on bedrock surface. Composed of ang ul ar to subangular rock f ra gments, 1/4 to 12 in . (0.7 to 30 cm) in diameter, ganerally rlecreas irr{J towards outer edge of unit; silty matriJl. VOLCANIC ROCKS - Darir: gray to grayish-pink. undifferentiated lava flows; consists of alkali olivine basalt, amygdaloida( basalt, intermediate latite, and rh.,.odacite; local xenoliths of granite and sandstone. TEMPE BED S - Interbedded strata consisting of ",bundant pink to recl, poorly to moderately soned, pebbly IIrkooic sandstone; le ss abundant tan, brownish·green, ye ll ow, and purple, moderately· we ll sort ed silt- stones; pink to groen, poorlv sorted volcanic arenite and green to whit(l tutt. 80undarill:l b(ltween b(lds are generally sharp, locally gtlldational; bedding thicknesses and ITlEIdian grain· size decrease upsecti on. Abundant sedimentary structures include cross·bedding, channel scours and mud cracks. Type locelity north side of Tempe Butte, Tem pe , Arizona (SE 1/4, SE 1/4, NW 1/4, Sec . IS, T. I N, RA E). CAMELS H EA D FORMATION Type loca(ity west end of Cameillack Mountain, Phoenix, Arizona (Paradise Vall ev Quadrangla) (Cordy, (lnd others, 19n ) (NW 1/4, SE 114, NW 1/4, Sec. 17, T.2 N, R.4 El. Papago Park Member - Bri ght tu brownish red. moderately sorted, we ll stralified, arkosic fangfomemte composed of coarse-greined pebbly sandstones with subangular to subrounded da,ts of granite and metarhyollte, 1/2 to 12 in. 0. 3 to 30 cm) in diameter, al ternating with finer·grained, micaceous, arkosic gritstones, sandstones, and siltstones. EJlhibits graded bedding. parallel· and cross·stratification and local channa! scour·and-till slroctur(l:l. Type locality southaast pan of PaflilgQ Park Pedim!lnl, Tempe A ri wna (SE 1/4. SE 1/4. SW 1/4, Sec. 10. T.I N. R.4 E). Stadiu m Breccia Member - Reddi sh brown. coarse· grained . poorly sorted and stratified, m<:rss ive erkosic brllCcia. Clasts ara angu lar to subangular. fresh and weathered, 1/ 2 to 18 in. (1 .3 to 45 cm) in diameter. s(ightly imbricated; consists of granite (40 to 70% I and metarhyolite 125 to 55%); locally ciasts are almost entiraly metarhyolite. MauiK is silt <lnd fine sand wi th rock fragments, ferrugenous cement. Locally int er· bedded with sandstone layers, cut·and·fill stroctures pretlllnt. Type io(:;)l il y ooscllilll st ad iu m, Papago Parir: Pediment, Phoenix, Arizona (NE 1/4, NE 1/4, NW 1/4. Sec . 9. T .! N. R,4 EI . Bar nes Butte Breccia Member - Reddisil-brown, coarsc-grained. poorly sorled and :;tratifiud, massive arkosic breccia. Clasts are allgular to subangular, generally fresh, 1/4 in. to 15 ft (0.7 to 4.5 m) in diameter, slightly imbricated; consists of clasts predominately of granite 170 to 85%), and of metarhyolite 1 10 to 20%) in a matrix of rock fragmenlli and ferrugenous cement. Locally interlayared with finer·gralned beds. channel scours CQmmon. Type locality Ban)os Butte, Papago Pal k Pediment, Phoenix, Arizona (NE 1/ 4, SW 1/ 4, SW 1/4, Sec. 33. T.2 N, RA E). Zoo Breccia Member - Purple to red dish·brown, coarse-grained, unsorted, poorly stratified. massi ve breccia. Clasts afe angular, .fresh, 1/4 in. t02 ft (0.7 to 60 em) in diameter; contains clasts of metarhyolite (30 tol00%), granite (0 to 35%), and a small amount of a di stinct dacite porphyry. Matrix of silt and clay, fer ru genoos cement. Type luea li ty Phoenix: Zoo, Pupago Park Ped imont, Phu enix, Arizona (NE 1/4, NW 1/4, NW 1/4. Sec. 10, T. l N, R.4 EL Basal Mamber - Red to purple to br(M'n sandstones and diamictons. locally interbedded with green to. white tuffaG&oos sandstones and brecci as; poorly to modera tely sorted and stratified; angular clasts from 1/4 to 8 in. 10.7 to 20 em) in diameter; uf local derivation . Panorama [0 [he Wl'$/ and norlhwCfl of Papago Park Pedimellf, Phoenix, Arizona/rom Governor Hum's tomh the Phowrix Zoo, SEV., SEV., SEV., Sec. 4. TIN., RolE. (PI/olograph Nos. 4881, 4882, and 48JJ4, T. L. Pewe, Dec. 101, 1985.) c B 1 300 Go lf course 700 • " Ii Modern Salt Ri ver Channel E H 0 '" !!! I eo> £" a • VERTICAL EXAGGERATION Elevation in feet E I 2 TIMES o • 0 5 U - '- . I I '/ '/ I \ \/ / -\, o • " .$ • 0 I i/Pf - \ \ -I 1 '_\ I - / '- - _, - \ 1- J/ _'- - - • - GEOLOGIC CROSS SECTIONS For location of cross sectjon s, see Map GI -2-B F 1600 1300 " 0 " e U " c • U SCALE 5 '; \ / K J .Scotudala Phooni. (",,;: • Pa Pi< PWdIm.wt ---" . Tempe EXPLANATION E 0 1, GREENSTONE DIKE - Gre8f1 to greenish·black, highly altered and fractured, fine-grained intrusive rock. CAMElBACK GRANITE - Pink, coarse-grained to porphyritic granite; contains large pink feldspar crystals, 1/4 to 3/4 in. (0.7 to 2.1 cm). locally hi ghly shear ed with granulatiOfl and alteration of original minera ls, Cut bV veins of quartz, and dikes of aplite and greenstone; xen-oliths of malarhyolile and a dark, fin&- grained rOt:k. Type Io<.:ality Cameillack Mounta in, Ph oen iK, Arizona (Par.;Jdise Va ll ey Quadrangle) INE 1/4, NE 1/ 4 , SE 1(4, Soc. 17 , T.2 N, R,4 E). TOVREA GRANITE - Gray, coarse·grained, qu art z·biotite gra nite; large rounded crystals of gray quartz, 1/4 to 1 % in. 1O.7 to 3.2 cml; segregat ions of farromagnas ian minerals altered to epidote and chlorite. Wea thers dflBplywith red ox idation rind, 1/4 to 1/2 in . 10 .7 to 1.3 crn) thick; cut by greenstone and apfite dikes. Type locality Tuvr ea Cast lo, Papago Park Pod iment, Phoenix, 'Arizona (SE 1/4, NE 1/4, NW 1/4, Sec. 8, T .l N, R.4 EI M ET ARHYOUTE - Gray to pink, oronge·weathering, blocky. loli ated. luw·g lade metamorphosed rhyolit e; locally porphyritic; commonly layered. with flattened pumi ce inclusions; epidotized; locally cut by gretlnstone and aplite dikes. TIME RELATION OF MAP UNITS Qefb 0 c l> -< Oofl m " z l> aefm ClIgm " -< Tv -< m " n -< nb l> 3 " 0 -< Too • ::t 0 0. Ahi iew /0 Ihe north 0/ Papago Pork Pediment, Phoenix, Arizona/rom over Ihe Salt River. Pediment exte'lds;'1 all directlOll s/rom Ihe smofllnselbergs In the center of the photograph. Pedimenr exposed in Ihe Slate Park in the eenler of the phorogrllph but covered by the Baseball Sfadium, parking fOl; and [he amusement park: ill ti,e /oregmulld. Washington Sfreet is atlhe ha.1i! 0/ the photograph (see map GI·l·B/or locatioll 0/ (Photograph No. PK24, 2RI by T. L. Pew{', AprilS, 1981.) KILOMETER M ILE 5 Y " " 0 U(ij • = c • oU Sal t N M .600 N I 1000 10 Mila. , n m z 0 N 0 n "0 " m n l> ;: OJ " ;; Z L 0 1600 1300 700 600 700 70o'-1 ______________________________________________________________________