71
Arizona Geological Society Digest, Volume IX, December 1971
PERMIAN SEDIMENTARY ENVIRONMENTS IN SOUTHEASTERN ARIZONAl/ by William C. Butler Department of Geosciences, University of Arizona Tucson, Arizona
INTRODUCTION
This paper synthesizes work on Permian depositional environments of southeastern Arizona and is an outgrowth of the author's Mas ter of Science thesis (Butler, 1969) that describes a 2,500-foot Permian stratigraphic section in the Empire Mountains of Pima County, Arizona. Permian outcrops of the Basin and Range Physiographic Province in southeastern Arizona are commonly faulted, intruded, and incomplete. Though outcrops are unknown in the portions of Maricopa, Pinal, Graham, Gila, and Greenlee counties shown in the following maps, data are interpolated into them from information available to the north and south.
DISCUSSION
The Permian stratigraphic section in southeastern Arizona (Bryant, 1968, p. 38- 42) from bottom to top is as follows: the Earp Formation (Virgil to Wolfcamp); the Colina Limestone (Late Wo lfca m~? to Early Leonard?); the Epitaph Do l omite (probable l ower Leonard); the Scherrer Formation (Early to Middle Leonard); the Concha Limestone; and the Rainva lley Formation. Species of Para fusulina, indicative of Leonardian or early Guadalupian age ---- (Sabins and Ross, 1963, p . 363; Ross and Tyrrell, 1965, p . 618), are commonly found a few tens of feet below the Concha-Rainvalley contact. A lithistid sponge, Actinocoelia meandrina Finks, is recognized in the l ower part of the Concha Limestone in south eastern Arizona (Bryant, 1968, ~. 41; Butler, 1969, p. 47). According to Finks (1960, p. 17), this sponge occurs in higher beds of Leonard age. Therefore, based upon sponge and fusulinid studies and stratigraphic position, the author woul d concur with Bryant and McClymonds' previous interpretation (1961, p. 1330) that the Concha Limestone warrants an age assignment of Leonard and Guada lupe (?). All formational contacts are apparently conformable ex cept the top of the Rainvalley which may represent an upper Permian, Triassic (?), and Jurassic lacuna in th.e sedimentary record. Although the Permian stage boundaries in southeastern Arizona are not yet firmly established, it is hoped that t he abundant conodont fauna recovered by the author from the Colina, Epitaph, Scherrer, Concha, and Rainvalley formations will lead to better biostratigraphic control. l / Contribution No. 30, Department of Geosciences, University of Arizona, Tucson, Arizona . ~ I\) ' ...... ' i \ . I !---\, \' #/ \ ! '..:! /' (=-·~'~ C~_: 0~_'~-~ __ I. ~- ---- I 'be ,.. State line ----- ...... ,..1 ...... ( ...... I /1- Cou nty line
i l" Permian outcrop " ';;'-' 1. C C'~IIT'y \~ 'I ''\. " .-·f' J \. rr-· __ -2500_ jGR£E ' k [~, J "Y; a- Well \ r ,../ ...... \ " ' \. ,'/ t ,// "" \. "\ i "'/ "'.,, 10 o 10 20 30 -'10 ) " '. t\ / , '\ '. ' miles I i '\ '.r', I \ I i _JOOO \ ( j- --\---, / //" ~", \ ~\ :0 \ i N I / " \ \ ~ ! l,! \ I I / \ \) Olx \ - I , '1AL (our.TV I / \ \l ~ i W -:'--=~-.------; c-",~, ;-- -- t ____ ./.::-:::J~~~~A~ '--C :' o:'\------~~:,~~j~ \, __ i } -...... /1 / C ~ L " I SE cou ·rv \ \!w , __ , '-,Coo_ '/ \ \ \, i Z i ~- I I \ \ i-___! '-- '-'''00-.., I I \ i ------t 1,.<5"\ ~: !---- ____ , \ ~ ~ , ',---- :.... -- ", :- , - ...... ,e>q, " , I . ! ____ , i '-- .\ " \ ' 1'~/ /' ~:,l----~--- '-i---,ii \ \ , ,. ~ [ i " , ' . (/---" '1-,,- -- \ \ r-----\--~-\------.,:~:.;~ \ .~---+~ \\ \ i '. \ i • " ~\\ - , I " • v'b ,_l~::;~;~Acl CO CN~. " ' '\ 0 H ,OAL ('O CO'J N TY "-'\-, ------. "'e__ ::"\ ______" "' ______~ __ ~:,' __ i \ , " '-- 'h C S l f lrR. 1%"
Figure l.--Rest ored Permian Isopach Map . Co ntour Interva l 500 feet. Contour Lines Dashed Where Inferred. 73
o o -=:t rl <0 > H Q) +> C H g +> C o U
P <0 ~ .c tl <0 P o en H '0 H <0 C o Q) ...:1 '0 Q) H o +> en Q) 0:: I I C\J EARP FORMATION
Epeiric seas withdrawing intermittently duri ng Virgilian and early Wo lfcamp i an times coincide with increased continental erosion and t he deposition of clastic sediments of the Earp For ma tion parallel t o the Pedregosa Basin axis . Figure 3 is an isopach map of the Earp Formation and indicates that the thickest accumul ati on of Earp deposits is in east- central t o northea s t Cochise County. These deposits are mos tly carb.onates in contrast to a de ltaic t ongue (Lodewick, 1970, p. 8) composed of mostl y silt- sized clastics extending from northern Pima t o southern Cochise County (Figure 4). Streams transported terrigenous material down the pa l eoslope from the genera l vicinity of the Naco Hi ghlands (Figure 5) in approximately southern Gila County (Rea and Bryant, 1968, p. 809) t o the delta and associated tidal flats in the southeast . Bryant (oral communication) believes considerable erosion was taking pl ace in approximately northern Pinal County and west Df Winke l man and Superior a nd in central Graham Count y wh ere Cenozoic r ocks now unconformably overlie Precambrian rocks . The correctness of this idea is reinforced by Figures 3 and 4, which indica te that at least one c onspicuous s ource of Earp clastics was near central Pinal County. Detailed stratigraphic sections of the Ea rp Formati on made by Lodew ick (1970) and Micklin (1969) reveal the following mostl y intertidal faunal association for the Virgil and Wo lfcamp stages within the unrestricted basin: ostracods, a lgae, echinoids, f oraminifera, crinoids, pelecypods, gastropods, brachiopods mostly of the spiriferid group, worms (?), ten genera of fusulinids, and five genera of conodonts. Rarer occurrences of syringoporid and rugose corals and bryozoans were also noted in this biofacies.
COLINA LIMESTONE AND EPITAPH DOLOMITE
Foll owing Earp deposition, a marine transgression from the south resulted in the deposition of the Colina and Epitaph formations (Figure 6). Although the Colina-Epitaph interval is assigned to the thickest accumulation of basin fill, the embayment was shallow during the Colina-Epitaph transgression. The northern cra t onic s ource areas were essentially eroded dow n to near base level, except perhaps in southern Maricopa County, and only very fine-grain detritus was being supplied. Mild tectonic activity is recognized in the area referred t o a s the Burro Uplift during this transgression. However, rather than acting as a significant s ource a rea , the uplift was merel y a barrier t o sedimentation. Pa leomagnetic evidence strongly suggests that southern Arizona was !l;e ographica11y within ten degrees north or south of the equator during the Permian period (DuBois, 1964, p. 43; Nairn, 1964, p . 555 and 557; Dietz and Holden, 1970, p . 34) . Perhaps both the Burro Uplift and the Florida Islands were similar to the mangrove islands, cays, or shoa ls observed t oday in tropical areas. During Colina and Epitaph time, a seaway extended north to the Holbrook Basin, which is sometimes referred t o as the East Central Arizona Basin (McKee , 1967, p . 204 ). This seaway was constricted by 1) the Burro Uplift at the juxtaposition of Graham , Cochise, and Hidalgo (New Mex ico ) counties, a nd 2) by a sha llow platform to the west . Intercalated dol om ite and gypsum (Figure 7) f or med in both the Holbrook and Pedregosa basins as a consequence of the shallow water, the high rate of evaporation, and the j •• .... t \. 1 \ 1"-+--800-- I ;' '.1 I ~---' i , .~~~~~~_ ~~~_~T.~.J'). / .-._.J ! /- State line ___ ,200;- / '. II .___ .I·.J-..'" _---_ ! \ • ./ \ 1 ..... - Fi gure 3 .--Isopach Map of the Earp Formation. Contour Interval ....;j 200 feet. Vl -'l 0\ ·.... t \. ! i I '. ~~ . ...: i , .~~~~c:~~~. 2:~~_~T.:" . _\ .-._.J i /- State line l '. ,.f-'~ ! i '. r ! 1/- County line I '. I I i \ \ i It- Permian outcrop .------.. \\ GIL A COUNT'!' .--1.) i \ r",J i iGRE£NI..EE COUNTY o- Well \ rF i t. i \ 'J~ i \ l ! \, i 10 o 10 20 30 40 I '. I miles i \r\ 1 ! -:~. r----l '\ ! : q:i O ' N " I ' Z:'=! I " ,i i O!x '------..., ___ __ I i -' ------'- . - - - - - . -----.- - - -; ~~~~~;-~"~L - -.------. _____ ~_~~~M._:~U_~~~_._ . _. .~~,~j! i " " 1\ , \ COC H I SE COU NTY I ~ Z i " ' i \ \ \ i , i + .... "\ ' ..... __ , \ I \ \ \ i , i ""- - \ i \ \ 1 / i ' ..... \i .A \ : / .... ! r. \ " ---1 ___ - ...... \ /' I \ ...... ----In ...... , /" ! I ...... ----~ .. / --..... \ , LI ______1I " \ ~I ~. , : . i"\ ~ -- - - i- - +--;- - 1-~ ------~i· ! i I I . ,I i I I • , '~~I/' ..--.'~1...... : - 0 .\iI ' " .~- -.- - j / I . ~~ Figure 4.--Clastic Ratio Map of the Earp Formation. ~ ...... /\, i ' ...... \ . I I MARI CO ~CN.N TV \. \ I i.. ·...: i r·_·_ ·_·_·_·_·-.....:.;;:\.. "" ' I , I f I I / .~_~- . _ . _i i /~ State line i \,~ , ~.t ! ,'\ ...... - ! //. County line ,':' \ "'-... t :- ! • . Permian outcrop .. \ GI L..A C OUNTY...... \ - I -i \('lACOJIiS .... D ! o- Well H IGt1LANDS ~ ~/ [G"'''EE COU Nn \."• .J \ '4 ' ...... 'VG " I) 1\111\ • ...... :.:::: • 10 10 20 30 1'1 I I 1\\ I ...... A '. o 40 i .... "1--\- '. r ~S \ \, r' lll miles i ...... V"\ ,,\1: 11/..- r ' 1-'-'-1' ~\ :0 .. N ::-,,' )\ .... 0'_~ ,._._.",~ c::' ; l., ~!~ ...... ~"- "i. __ GRAHAM COU N TY::- ,~ , - -...... - , - _._._._. ___ ._._._. - ~ I ::- "'!> I COC H'SE CO~N;; -'- ~ 8TJRRa. ~:- ---~ ~ SHALLOW '\ UPLIFiT-"" ~ ! -<'\ """''''!'\' 't'u{O~, SHELF ,!o !' \ -:./~ ~\ ! ! '/%lv i i "" \5': AREA , /' ! l-.- ---~JfJ PEDREGOSA ! .1",,...-- r ______..;-A..· ___ _ ! ! I111 i i ~ "XII: i \ i '" BASIN i .______i , " ! "_ .. l~.ANr A C R uZ COUNT Y , i : : ._ . __ .. _ .. _ .. ______.1! .. ______. _ .. _. __ . __ .. _ .. __ ._. ._ ___ .. ______:.~·_l. ______~.~~~_~_.:~_u~.~:. _____ ._ J MEXICO we BUTLER. 1.. 9 Figure 5 .--Pa leotectonic Map of the Lower Permian in Southeastern ---l Arizona . ---l -.;J CP --:.~~\---"' ;'! i. .. ~ 1 ! ~ ,,\ / Ii I ! ~:~~~'_:.':: ?~":..-.:'. __ \./ // ,/. .___ i I ! / State line ! 0'-/ __·v..... /' ,-f--; / ! /Y" /' \ ...... / ,- / / I //- Cou nty lIne ,,// I ~/- \...... !,,// /1 ! I /' ! .,// ...... ,/ ! I Permian outc r op --. _ . _ . _ .• .,/ ... _ '. (;'. l. :OV!?/ .\ / I J ./ r..rP \ ..- j -- 'f / 'Ir // ,...... / ..>. _ ...... rr-' // ! G~f.l'''ir c. ou ... ·,: o Well / ./ ...... \ r I ...... ~. / I ,/ ,// ...... d:fJ,...... \ .... ./ - r ...... ---....., './ / 1 ,/ /" --...... /': 10 0 10 20 30 40 / /" -- !...... I / '. / 'I ..,.c; I ,/ ...... / &00-- I /...... I / '. / : miles / / // j../ I I \r', II / / I ""-- _-, / /, / :_~._. I / / /,(j:IJ-- ! I I ".~/ ~ ;I' / " /- ! I I /" /\ ..{I O /! N / / / ' #---.... I I / / !/z:'o;/ I / / ( .(' ", \ I / / If)l~ . . _{_ . ____ ._ I __ ... _.- .. -\. .":.':.. :o~:: '. :-- -/~ \ \ )' / / I i./ a:!~ "'\ ",{"I. "::O\.. f\,TV ' \ GR j I1A' CO,..NT"f / / / .~. «1 } \ , " I ~ '-"""'--="'-'\- "'\-'- \ -" ' - ' -f-"I-"--r '-' -~ ' ';:;; , \" " I' / /!w , ',\OC ~ " E Cfu.1' / 0 " " \ I ! \ \ \ \ \ I I I j3------, __ , , \ I i f \ \ \ \ \ I, / ' ~- 200 - - --i- , '. \ . / \ \ \ \ \ / Y , -_ , ,~ , ! I \ \ \ \ \ -- / , /_""0 - __ '-.. ~ , __ , I . /.p0 ®~\ " \ I " . ~~-'- ....~/ /:/!..:..___ 600-_--;,-, _,___ ',--- I .' y., ~~.Oo.... __ ! ! ',! ,'000__ -;-- f---, ...... ------...... '" .! lit, x;:: ~ . !200_ -t- ...... 1 --___ \ ! '! ,-sf' . --l",,-_ . ~,', -"", • .x l . ___ "':'-- \ \ ' .'. #'''', : - __ ' K~' I ,J~ -. ( -.- -- ':( / : i /... ___> -, I i r1 . -j : .# ~ /. _ "'j" ._ __ +iIi III \ \\ ~!' . ~'%! ' /"",~~,#A'~;"", 1, ~ S.A "' l ,\ C R U l CO & Nl\ \\ i· . / //"''f_cP-'''''~'' - '-l , \ ~ \ ~ . i / / / I, f '\. ~'\. .. ~.-~ . ~ \ \ ,.'- ! _ :::_: ,, _ .~ .. ').cI',.'t~/J.ul~'-"_"'::,' J'\ "" 13' - .. " .. -.,-\...>.-.:-,.,,-.. ~ .. - .. - .. - .. - .. -. ,,"-.. - .. - .. -r- )'. I 7 I / I '\ \ \ ','-,'<',_ ~.xiCo--,,"~ ..--/ // / /// / ! .' \ \ we BVTLER. 1%9 Figure 6 .--Isopach Map of the Co lina Limestone and the Epitaph Dolo mite. Co ntour Interva l 200 Feet. 79 frequent accumulation of dense brines . Chloritic marls, silt stones , argill aceous dolomites, carbonaceous dolomites, intra formational breccias, and thin beds (2 inches to 2 feet) are also characteristic of the Colina-Epitaph interval in eastern Pima County. Algal stromatolites, desiccation cracks, erosional channels, ripple and cross-laminations, and oolites are rare in this interval. All of the above features infer intertidal and subtidal and subtidal conditions within a shelf lagoon (Laporte, 1969, p. 105) existing at this time with c lastic source areas remaining to the north as interpreted from Figure 8. The Co lina Limestone becomes progressively less fossili ferous from the subtidal type section i n central Cochise County to the intertidal environment in Pima County. Wilt (1969, p. 77-79) concluded in her study of the Colina Limestone in the type locality that the combined occurrences of unabraded shell hash and the predominance of micrites and biomicrites in this formation are due to scavenger organisms breaking up the unwinnowed substratum . The transition from the subtidal to intertidal environment is also marked in the Co lina Limestone by a slight thinning of the formation over the Earp delta in the Empire Mountains (Butler, 1969, Figure 27) . Furthermore, there is a significant proportional increase in dolomite and clastics superjacent to the delta in this area (Figures 7 and 8) . A t ypica l fossil suite from the Colina Limestone lagoonal biofacies suggests that bryozoans, echinoids, pelecypods, and gastropods were more or less evenly distributed throughout the lagoon . Brachiopods were best adapted to the central part and the six reported genera of fusulinids have been found near the inlet of this Permian lagoon. Porifera have not been reported in this particular biofacies and corals are rare. One criteria for recognizing a change from the unrestricted intertidal environment to t he slightly restricted intertidal is manifested by a corres ponding change from a community with common crinoids and fusulinids to one of common bryozoans replacing the crinoids and fusulinds . When conditions became more saline, as recorded by the gypsum de posits in the Epitaph Do lomite, the faunal diversity was reduced to only four genera of common brachiopods, five genera of common gastroPods one ty~e of coral, and one echinoid genus (Gilluly, et aI, 195 4, p. 41) . This reduction implies that gastropods have the widest tolerance of salinity . SCHERRER FORMATION Renewed uplift along the Deming Axis (Turner, 1962, p . 67) or perhaps less likel y either tectonic activity in the Uncompahgre Uplift area of southwestern Colorado, or the Zuni-Defiance posi tive area of northeastern Arizona and east-central New Mexico (Baars, 1962, p. 161), initiated the rapid influx of two bi moda lly, but well- sorted quartz sand bodies to the south. These orthoquartzite bodies are separated vertically by a dolomicrite member which is slightly sandy in the shallower parts of the basin. The sand in the essentially low-energy carbonate-forming environment was possibly blown into the basin where penecon temporaneous (?) dolomite was forming. Some fossils collected and identified by Bryant (1 951, p. 112) from this middle carbonate unit are referred to the somewhat deeper part of the intertidal facies in northeastern Santa Cruz County. Crinoid stems, Archaeocidaris sp., bryozoans, Dictyoclostus bassi (Peniculauris ():) o ~,/ \ . ,~-j I \ . !, , i~~~~~':~~_~?~_~T:~ __ .\ /,-,_.;-.___ 1 / - State line i \ fr - ! , /'- County line i \ i i i \ '. ! . - Permian outcrop ______: \ G ILA COutH Y ._ . ... .\ I • r.;J iGAEENLEE COUNTY .-Well '. r l : \ r • I ",,,,.,; , . '\ i 10 o 10 20 30 40 \. 1 \r. I miles t~ i-----, 'j w Ceu T LEiIt. 1169 Figure 7.--Limestone to Dolomite Plus Gypsum Ratio Map of the Colina Limestone and Epitaph Dolomite. -~ - ~ ,/ \. ! ! ! \ ~ ... -... I MARI COPA COUNTY \. _ ! I ;------\ . -'~ '--- i /~ state line r I i \ f - I /1- County line Ii \'• I i, I \ \, ! Il - Permian outcrop ___ _A_A_A: \ GILA COUNTY .- -f''\ ! \ rr..,J ,i.,------IG REENLEE COU NTY: . - Well \ r ,'! "\ ! \ ,,1,/ I " , 1 .... ,./ i ',\, i 10 o 10 20 30 40 / ' 'I / ! ",..----...... , \..-, 1 mites I V '-, \,~ : I /1 " , \ (" r----l / / i " '\ \ ) i N I I! ,.-----.., \, \ i w. C BUTLER, '.9 Fi gure 8 .--Clastic Ratio Map of the Colina Limestone and the Epit aph co Dolomite. I--' ~assi of Muir-Wood and Cooper, 1960), Composita sp., and l arge and small ga stropods are common in the fossil assemblage. Euompha lids, bellerophontids, and Chonetes sp. are less commonly f ound. The orthoquartzite bodies also exhibit l ow -angle tabular pla nar cross-bedding which in addition to the fan-shaped blanket geometry of the entire deposit, infer a high intertidal littoral environment for the Scherrer Formation. Longshore drift was virtually ineffective in dispersing the sand parallel t o the shoreline. Regul ar echinoids, common in the Scherrer dolomicrite and the l ower cherty Concha, lived on a relatively hard mud - free substratum (Cooke, 1957, p. 1191) that was subjected to moderate current action. The Scherrer, 300 to 500 feet thick in southern Cochise County, is projected to have been 700 feet thick in northern Cochise County (Figure 9) where it is thought to be transitional with continental beds to the north (Sabins, 1957, p. 500). At least some erosion of Scherrer source rocks pre sumably took place in central Graham County a long the Deming Axis. All Pa leozoic rocks have been stripped from this area and geologic cross sections show Cenozoic rocks resting unconformably on older Precambrian rocks. At the time of this writing there has been no acknowledge ment or forma l description of a fossiliferous stratigraphic secti on of middle and upper Scherrer and lower and middle Concha one-quart er mile southeast of American Peak in the Pa tagonia Mountains, Santa Cruz County, Arizona. This section was recently recognized as being Scherrer and Concha by the author who grate fully acknowledges the help of graduate student, Richard Moores, who is presently conducting a field examination of the area. An interesting feature of this section is a brecciated zone with large siltstone and sandstone clasts in a carbonate ma trix occur ring within the middle Scherrer carbonate unit (Figure 13). This soft-sediment deformation is inferred t o be a submarine landslide, perhaps triggered by tectonic adjustments along the Deming Axis to the north. A second significant feature at the American Peak section is the unusual gradational contact between the Scherrer Formation and the overl ying Concha Limestone. CONCHA LIMESTONE AND RAINVALLEY FORMATION The Pedregosa Basin slowly subsided during the time of deposition of the Concha Limestone as evidenced by an undis turbed and diversified deeper-water shelf fauna above the near shore deposition of the Scherrer. Many productid brachiopods etched from the Concha reveal delicate spines still attached and unbroken. The massive clean microsparites of the Concha are relatively widespread. These detritus- free sediments reflect deposition below effective wave base and represent the maximum inundation of the land area by the Concha sea. Evidence for a relatively shallow but widespread ex tension of the Permian shelf in western United States is inferred by the previously noted occurrence of a time-stratigraphic, restricted actinocoelid sponge in western Wyoming, northern Arizona, southern Nevada, southern New Mexico, and western Texas (Finks, et. al., 1961, p. 564) in addition to the southeastern Arizona occurrence . Comparisons of time-equivalent brachiopods c orroborate the existence of an arm of this inland sea between western Texas and northern Arizona through southeastern Arizona ,,,,. \ ~-j I , I i , ""ARI COPA COU NTY \, _ i I r-- · -·-·-·-"-·-·- · --~\ ,.-.1,--_. ..: "--- ! / - State line ! \ ,- I //.. County line ! " i i iI "\ '\, ! ., . Permian outcr op -_._._._.; \ GILA COU :~~j __ r\ I '. r jG FlE ENLEE COUNTY o-Well \ r i \,,,,,,i "" 10 o 10 20 30 40 " miles "\r> j-' - --'l ...... , I \ <{i O i N \ ~ i~ '------, ~ N:W ! PI NAL COUNTY , / / l_ ,.... li:l2:« I ------~ 'r - --~\-·- - ---·--- - ..... ,-;;.:;;-~~-U-;;;--·"-~- i GOAHA,! COU N" . } " " \ ".I 1 \ \, "" .00 , I \\ "00 :" / ;'/!Oll}i/ 1 \, " , I \, '", I: 1 i i "'" t .f /! 1 i------i~ '. \, , "" !, 0 / i / 'b, \ , ' ,0 / : / "\ -- ~!---"l' / !; , r---\----- ~ ' · ·Oo 'AA' /:,d'!1 \ i ~ ' . I /' -""" i \ ~ . • I d' ! '" \ i \ '. / 'i '\ 'i • ./ / I, I '------'... i • ./ / I I H ,OMGO COUN" _J 't·::: ~'~\:~ -':"~'-'.J.,;"Q-~ -~~>C;::7'~ ~7'::- ",',L ------ W C BUTLER. 19&9 Figure 9 .--Isopach Map of the Scherrer Formation. Contour Interval co 100 Feet. \.>l :g i ' ! "'\ \ II " __-' II !: ! , \ \ I ._. ___1 I . \ / . State line "'''<~ '' '''''"C\ '\\. \y' - ~-" \\! ! \I r'-'-' " ,\ ,! I //. County line It - Permian ou t crop !i' "I "' ."" <•••••• - .,', . '\'. " \ ' i,!;I"".' Tok COUNTY , ."- .' .-.-.! \ , ' >",.""; " , \..." . \ !, o- Well '\ \ r <\:;,. \ \ '- \ I ' \~ '{ \ '. I 10 o 10 20 30 40 " ., ", \ '_.-. _., miles ...... , ! " \ \\ ~,(. \\ !° ! ...... 1 \ \ \ ~i I ' "-'-"-;i \ \ \ \;\ i !ti'O,:l-, •. _._._L_ N " ", ; \ \ \ i·.:b ~_" ; , " \ , \ ' . " , ! ' " , , ..... <.... ,. __ . _., .,, """'-'-'_._;_._._._, ••,. . _.'--"<.- -il'-.. , 'i" - -"_ .-':.."-- _.-.-"-- .---....-" ''00'-'-'- P,... '.- '''0;;. ;, .- .L._\ ._ . _ ._.\,.....~;<.",~, , , !. , " i ' \ } .. _. -', - , , -", I 'i \ \ ' " " J '" _ ...., \ , , ,,-' .... " "\ ! J " ', \1 \ i " , v' ~' ~: ; , • \ , ' 'A. ... " 'Ii " ...... \.j i \ ' l.\ _____ .\. " ~ ';: ,.~' ! \.,,-' ..... " ''', . ;i ~ /-..... i \ \ ;\\ \ '-", ., '. J 1, ,. ; \ ", /--"'" \ ~\ -t-·-·\ J /",• _, \ • ' ! ,\ .,\ ,. \ r , I • • \ ' I \ , ~.... \..J " ".. '-+-"\\ i .. \ , • / / • \"\ \ _\\_u __ ,! ,, _.. -.\ __.. _\_ .. _-, - " " ' . ' --' -- L,,..~__ , _, \ ' <.\...\ , '..... • ~ _ _~,i /_ __/_ "_/"_"" \ "_"_',\. " _ '>""-\ . "' \--", , ", .\H'O'~-,,- _t'\\ \ ''\, --, .. _.. _.. _-=-=-- MEXICO, \ We BUllEIt. 1.9 Figure 10.--Isopach Map of the Scherrer Formation and Concha Lime stone. Contour Interval 200 Feet . (Feth, 1948, p. 91). Another group of widely distributed fossils in western United States are the Permian fusulinids (Moore, 1964, Fig. 296). The zone of Parafusulina, which dominates the fusulinid faunas of the upper lower and lower upper Permian series, is found not only in southeastern Arizona, but also in Sonora Mexico (Cooper, et. al., 1953, p. 6), western Texas, southern New Mexico, Washington, California, Oregon, British Columbia, Canada, and Alaska (Moore, 1964, p. C393). Arguments for and against a Permian seaway connecting the Leonard Sea of West Texas and Kaibab Sea of northern Arizona (Dunbar, 1941, Fig. 7) thro~h western Arizona was discussed by Stoyanow (1942, p. 1278-1279). Stoyanow believed that the sea communicated between northern and southeastern Arizona through eastern Arizona and not through central Arizona (1942, p. 1275). McKee (1947, p. 291) inferred that the Kaibab seaway was con tinuous across western Arizona. Other opinions concerning the extent of the Permian seas are summarized by Bryant (1955, p . 114-116). Supportive evidence that some physical barriers to the migration of early Permian pelagic faunas were at least partially removed by late Permian time between southern and northern Arizona is based on reconnaissance work by Clark and Ethington (1962, p . 104) who have determined time-equivalent conodont faunas, mostly Wordian (Guadalupe stage), in western Texas, southeastern Arizona, west-central New Mexico, southeastern Idaho, and southern and western Hyoming. In addition, conodonts have recently been found by Fred H. Behnken (written communication, University of Wisconsin, Madison, Wisconsin) in eastern Nevada near Ely. These conodonts have also been assigned a Guadalupian age by Behnken. Megafauna diversity compiled from an investigation by Bryant in 1951 indicates that the subtidal environment of the Concha Limestone consisted of crinoids, two genera of bryozoans, fifteen genera and twenty-eight species of brachiopods, four genera of pelecypods, two genera of cephalopods, twenty-three genera and twenty-seven species of gastropods, horn corals, and echinoid spines. The most frequently occurring fossils of this assemblage were the horn corals, crinoids, Archaeocidaris, and brachiopod genera including Composita, productids, and Chonetes. The megafauna of the superjacent Rainvalley Formation includes the following community: one genus of pelecypod, several genera of gastropods, fourteen genera and seventeen species of brachio pods, one genus of coral, crinoids, Archaeocidaris sp., bryozoans, and one nautiloid. Chonetes sp., echinoids, euomphalids, and crinoids are found in greatest abundance. Imbrie, et. aI" (1959), p. 72) would probably consider the latter assemblage equivalent to their shelly and Chonetes facies, which they attribute to an unrestricted, quiet, and deep water embayment environment. This author would refer the attributes of the Rainvalley to a slight shoaling of the Permian seas. About 2,000 feet of Wordian (Guadalupe stage) rocks crop out near El Antimonio in western Sonora, Mexico (Cooper, et. al., 1953). Although this sequence of rocks is about twice as thick as the time-stratigraphic equivalent Concha and Rainvalley forma tions in southeastern Arizona, forty-four genera and sixty-four species of mega-fossils, mostly brachiopods, have been identified by Cooper and others. The high diversity, in addition to the deeper water, conceivably signifies a less restricted and more stable shelf away from terrigenous influxes. Thicknesses of the Concha Limestone combined with those of the Scherrer Formation reveal a northwest-trending trough W C 8UTLER. 1169 Figure ll.--Limestone to Dolomite Ra tio Map of the Scherrer Forma tion and the Concha Limestone...... : \. !i- ' ~i 1j """~C""'__'-\ _,,~- -- ___ J ! /~ State line I • r , //- County line j '. i ! j '. \ I • . Permian outcrop ! \ GILA COUN" f) iGA"NeE< COUN" : .: \ r~J'--i "! . - Well \. r i '.! \ r , '. i \ ./ 1 '. I -J , \ I 10 o 10 20 30 40 miles ! \r\ 1-----, i \ :0 ! 1 j Figure 12.--Clastic Rati o Map of the Scherrer Formation and the Concha Lime stone . .Cf1 88 Q) C -rl ~ <1l .gE CI) I I as shown in Figure 10. This trough approximates the northwest tre nding axis of the Pedregosa Basin. Both dolomite and quartz sand increase steadily in a general south to north direction. This a~rees with the close proximity of the strand line to the north (Figs. 11 and 12). Beds of the Rainvalley Formation are more dolomitic, show more evidence of burrowing (?), and are thinner than beds below in the Concha . The Rainvalley features rare refluxion marks (?) and includes several quartzite beds. Both formations are fossiliferous and definitely subtidal in aspect. A typical megafauna of the Concha and Rainvalley in cludes: actinocoelid sponges; archaeocidarid echinoid spines and plates; diverse crinoid columnals; large gastropods of the bellerophonid and euomphalid groups; several genera of small turreted and fusiform gastropods; large brachiopods of the genera Meeke lla and Neospirifer, and large and small productids; small brachiopods of the PhricodothyriS, Chonetes, and Composita genera; fistuliporid and polyporid bryozoans; and corals of the l opho phyllid and dibunophyllid groups . SUMMARY AND CONCLUSIONS True wave- resistant biological structures or carbonate beachrocks have not been noted in Permian exposures of southern Arizona . Invariably limonite pseudomorphs after euhedral pyrite dominate the heavy mineral fraction of the insoluble residues from the carbonate. The environment is postulated t o have been one of reduction in view of the pyrite and numerous dark carbonaceous carbonate rocks. The lack of reefs or banks and the common occurrence of chloritic marl beds also suggest quiet, non-turbulent, and semi-stagnant lagoonal conditions prior to Concha deposition in Arizona . The inland-sea shelf area of southeastern Arizona lacked environmental stability. Consequently, faunas did not greatly proliferate and develop the back reef, reef, and fore reef facies such as found peripheral to the Permian Delaware Basin in southeastern New Mexico (Malek-Aslandi, 1970, p. 2330) and western Texas. However, Greenwood (1969, p. 173) and Zellar (1965, p. 33) both mention reefs or banks eXtsting in early Permian rocks of Hidalgo County, New Mexico. Lopez- Ramos (1969, p. 2412) also cites the existence of similar biogenic structures in the early Permian rocks of Sonora, Mexico. Localized bryozoan reefs are reported by Feth (1948, p. 92, 95, and 99) in his stratigraphic description of Leonardian rocks that crop out in southern Santa Cruz County, Arizona. Although the author has not examined this outcrop, he believes that due to the bedded nature of the "reef"-bearing zones, these "reefs" are actually bryozoan biostromes. Within the area studied, common bryozoans, common crinoids, and diverse and abundant brachiopods characterize the Permian sub tidal environment in a tropical climate. Shoaling is hinted by a marked decrease in gastropod taxa, but with the retention of many individuals . Accompanying this latter change is a subtle decrease in brachiopod diversity. Several genera of gastropods, such as om~halotrochus, Euom~halus, Goniasma, and Worthenia, endured a wi e range of ecologlcal conditions . Corals were found to inhabit a nutrient-rich niche predominantly in the subtidal environment. Brachiopods and crinoids are ubiquitous in the normal-salinity intertidal and subtidal depths. The echinoid Archaeocidaris sp. is least sensitive to depth changes. From present data the most logical environmental synthesis would be t o relate the regressive clastic porti ons of the Earp 90 Formation to a fluvial- deltaic-tidal flat complex and to consider the carbonate portion as supratidal to subtidal. The Colina Epitaph sequence which gradually encroached upon the Earp delta and submerged coastal plain presumably represents shallow lagoona l t o evaporating pan sedimentation, particularly in Pima County. The Scherrer reflects a near-beach environment. The deepest water basinal rocks are correlated to either the cherty or the fusulinid-bearing Concha Limestone wh.ile the superjacent Rain valley Formation inaugurated the final regressive phase . Maximum water depth in the Pedregosa Basin throughout the upper Le onard and lower Guadalupe stages was probably between one hundred and one hundred and fifty feet. This inference is in direct conflict with the interpretation of Imbrie, et al (1959, p . 73, 78) who relegate the Permian fusuline-bearing Beattie Limestone t o shallow 30- foot depth water both in the shoal and shelf lagoon environments. Figure 5 illustrates the irregular oblong geometry of the Permian Pedregosa Basin. Sedimentation decreased northeast toward the northern end of the Mexican Sonora Basin. The most active repository was centered in southeastern Cochise County with a subsidiary depocenter in west- central Cochise County. Based upon geometry, tectonic setting, arrangement of fill, the Pedregosa Basin tends to resemble the architecture of the "open ended" basin model proposed by Potter and Pettijohn (1963, p. 235- 237) . "Open- ended" basin models are characterized by their symmetrical cross- sections and oblong shapes which widen and deepen down the axial plunge. Sandstones, shales, and carbonates predominate as the type of fill. The clastic sediments are fed to the basins by deltas at the up dip ends and are dispersed down the paleoslopes parallel to the basins' axes . Furthermore, the thickening of sediments occurs away from the source areas. Finally, these "open- ended" basins and their distal source areas are located in areas of mild t o moderate subsidence and uplift respectively. ACKNOWLEDGEMENTS The author is indebted to fellow graduate students, Robin Holcomb and D. D. Trent, and to Professors D. L. Bryant and R. F . Wilson for their critical evaluation of this manuscript . REFERENCES Baars, D. L., 1962, Permian System of Colorado Plateau: Am. Assoc. Petroleum Geologists Bulletin, v. 46, n. 2, p. 149-218. Bryant, D. L., 1951, Geology of the Mustang Mountains , Santa Cruz County, Arizona: Univ. Arizona unpub. M.S. Thesis, 142 p . ______, 1955, Stratigraphy of the Permian System in Southern Arizona: Univ. Arizona unpub. Ph. D. Thesis, 209 p. , 1968, Diagnostic Characteristics of the Paleozoic ------Formations of Southeastern Arizona: Ariz . Geol . Society, Southern Arizona Guidebook III, p. 33- 47. 91 Bryant, D. L., and N. E. McC lymonds, 1961, Permian Concha Lime stone and Rainvalley Formation, Southeastern Arizona: Am . Assoc . Petroleum Geologists Bulletin, v. 45, n. 8, p . 1324-1333. Butler, W. C., 1969, The Upper Pa leozoic Stratigraphy of Total Wreck Ridge, Pima County, Arizona : Univ. Arizona unpub. M.S. Thesis, 138 p. Cl ark, D. L., and R. L. Ethington, 1962, Survey of Permian Conodonts in Western North America: Brigham Young University Geology Studies, v. 9, pt . 2, p. 102-114. Cooke, C. W., 1957, Echinoids, in Treatise on Marine Ec ol ogy and Paleoecology: Geol:-Soc. America Memoir 67, v. 1, p. 1191-1192. Cooper, G. A., C. O. Dunbar, H. Duncan, A. K. Miller, and J. B. Knight, 1953, Permian Fauna at El Antimonio, Western Sonora, Mexico: Smithsonian Miscellaneous Collections, v . 119, n. 2, III p. Dietz, R. S., and J. C. Holden, 1970, The Breakup of Pangaea: Scientific American, Oc tober, v. 223, n. 4, p. 30- 41. DuBois, R. L., 1964, Virtual Geomagnetic Pole Positions for North America and Their Suggested Paleolatitudes: Arizona Geological Society Digest, v. VII, p. 35-51 . Dunbar, C. 0 ., 1941, Permian Faunas: Geol. Soc. America Bulletin, v . 52, n. 1, p. 55- 8l. Feth, J . H., 1948, Permian Stratigraphy and Structure, Northern Canelo Hills, Arizona: Am. Assoc . Petroleum Geologists Bull etin, v . 32, n. 1, p. 82-108. Finks, R. M., 1960, Late Paleozoic Sponge Fauna of the Texas Region: The Siliceous Sponges: Am. Mus. Nat . Hist. Bulletin, v . 120. art. 1, p. 1-160. , E. L. Yochelson, and R. P. Sheldon, 1961, Stratigraphic ------Implications of a Permian Sponge Occurrence in the Park City Formation of Western Wyoming: Jour. Paleontology, v. 35, n. 3, p . 564-568. Gilluly, James, J. R. Cooper, and J. S. Williams, 1954, Late Pa leozoic Stratigraphy of Central Cochise County, Arizona: U. S. Geol. Survey Prof. Paper 266, 49 p . Greenwood, Eugene, 1969, Oil and Gas in the Pedregosa Basin: The Oil and Gas Journal, October 6, p . 171-173. Imbrie, John, L. F. Laporte, and D. F . Merriam, 1959, Beattie Limestone Facies and Their Bearing on Cyclical Sedi mentation Theory: Guidebook - 24th Field Conference of the Kansas Geol . Society, p. 69-78. Laporte, L. F., 1969, Recognition of a Transgressive Carbonate Sequence With.in an Epeiric Sea: Helderberg Group (Lower Devonian) of New York State, in Depositional Environments in Carbonate Rocks: Soc. Econ: Paleontologists and Mineralogists Spec. Publ . 14, p. 98-119. 92 Lodewick, R. B., 1970, The Petrology and Stratigraphy of the Earp Foundation, Pima and Cochise Counties, Arizona: Univ . Arizona unpub. Ph. D Dissertation, 194 p. Lbpez-Ramos , Ernesto, 1969, Marine Paleozoic Rocks of Mexico: Am . Assoc . Petroleum Geologists Bul l. , v . 53, n. 12, p. 2399-2417. Ma l ek- Aslani, Morad, 1970, Lower Wolfcampian Reef in Kemnitz Fiel d, Lea County, New Mexico: Am . Assoc . Petrol eum Geologists Bull. , v . 54 , n. 12, p . 2317- 2335. McKee, E. D. , 1947, Paleozoic Seaways in Western Arizona : Am. Assoc . Petrol eum Geo l ogists Bull., v . 31, n. 2, p . 282- 292 . ______, 1967, Arizona and New Mexico, in Paleotectonic Investi gations of the Permian System in the United States : U. S. Geo l . Survey Prof. Paper 515- J, p . 201-223. Mickl in, R. F ., 1969, Fusul inids and Conodonts of a Pennsyl vanian Permian Section in the Northern Dragoon Mountains, Cochise Count y, Arizona: Uni v . Arizona unpub . M.S . Thesis, 257 p . Moore, R. C., ed., 1964, Treatise on Invertebrate Paleont ol ogy : Geo l. Soc . America, (C) Prot ista 2, v . 1, 510 p . Muir - Wood, He l en, and G. A. Cooper, 1960, Mo r phol ogy, Cl assi fi cati on and Life Habit s of the Productoidea (Brachiopoda): Geo l. Soc . America , Mem. 81, 447 p . Nairn, A. E. M., 1964, Evidence of Latit ude from Permian Pa l aeomagneti c Data , in A. E. M. Nairn, Ed ., Problems in Pal eocl imatology, Proc. of NATO Pa l aeocl imates Conf., Univ . of Newcastl e -upon Tyne , 1963, p. 550- 558. Potter, P . E. , and F . J . Pettijohn, 1963, Pa l eocurr ent s and Basin Ana l ysis, Spr inger- Verl ag, Berl in, 296 p . Rea , D. K., and D. L. Bryant, 1968, Permi an Red Cher t - Pebbl e Congl omerate in Earp Formation, Sout heast ern Arizona : Am . Assoc . Petrol eum Geo l ogists Bulletin, v . 52, n. 5, p . 809- 819 . Ross , C. A., and W. W. Tyrrell, Jr., 1965, Pennsyl vanian and Per mi an Fusulinids from the Whetstone Mountains, Southeast Ar izona : Jour. Pa l eontol ogy, v . 39, n. 4 , p . 615- 635 . Sabins, F . F ., 1957, Stratigraphic Re l ations in Chiricahua and Dos Cabezas Mount a i ns , Arizona : Am . Assoc. Pe t rol eum Geo l ogist s Bulletin, v . 41, n. 3 , p . 466- 510 . Sabins, F . F . , and C. A. Ross , 1963, Late Pennsyl vanian-Earl y Permi an Fusulini ds f rom Southeast Arizona : Jour. Pa l eontol ogy. v . 37, n. 2, p . 323- 365. St oyanow, A. A., 1942, Ar izona Pa l eozoi c Pa l eogeography : Geo l. Soc . Ame r ica Bulletin, v . 53, n . 9, p . 1255-1282 . Turner, G. L., 1962, The Deming Axis , Sout hea s t ern Arizona , New Mexi co and Trans- Pecos Texas, in GUidebook of t he Mogo llon Rimm Regi on: New Mexico Geo l .-Soc . 13t h Field Conference, p . 59- 71 . 93 Wi lt, J. C., 1969, Petrology and Stratigraphy of the Colina Lime stone (Permian) in Cochise County, Arizona: Univ. Arizona unpub. M.S. Thesis, 117 p. Zeller, R. A., 1965, Stratigraphy of the Big Hatchet Mountains Area , New Mexico : New Mexico Bur. Min . and Min. Res., Memoir 16, 128 p . EDITOR'S NOTE Because of a delay on the part of the editor in the publi cation of this manuscript, the author wishes to add the following items. Tectonics Several major strike- slip faults have been postulated in southeastern Arizona. One such fault, the Sawmill Canyon fault (Lutton, 1958, p. 26), trends northwest through the southwestern portion of the Pedregosa Basin. The fault trend approximates that of the Deming Axis and the Mogollon Rim in central Arizona. Inter pretations as to the fault movement vary. Poole and others (1967, p . 880, 893) state with respect to the Devonian System, "Evidence f or the inferred right-lateral fault zones in southern Arizona is permissive rather than compelling." In contrast to this right lateral movement, Professor Spencer R. Titley (University of Arizona , manuscript in preparation) finds left-lateral movement to be the case . Titley's preliminary work with the Mississippian Escabrosa Limestone argues for a left-lateral interpretation of the Sawmill Canyon fault and for an offset in post-Triassic to pre- Cretaceous times. The Permian stratigraphic maps in this paper were compiled without presupposing any lateral offset of the Pedregosa Basin. If re- evaluation of the Permian data is in order, this author would concur with Titley's interpretation. Restoration of a 100-mile left-lateral offset in Figures 1, 2, 6, 10, and 11 from north eastern Santa Cruz County (south side of the fault) to southeastern Cochise County (north side of the fault), would match nearly equal thicknesses of rock and effectively minimize the depocenter in west-central Cochise County. But, at the same time, such a res toration would certainly make interpretation of Figures 7, 9, and 12 more difficult . To Muehlberger and Wiley (1970) the Texas Lineament in Trans Pecos, Texas, is viewed as being a repeatedly re-activated zone of right-lateral faulting with a displacement of about 200 miles. To Sales (1968, Figs. 1 and 9) the Texas Lineament is left-lateral and contemporaneous with other Laramide lineaments. The Deming Axis in Arizona could be a local expression of this lineament. Muehl berger and Wiley, in their review of the Texas Lineament, state, "For many reason, but chiefly because of the distribution of Permian and later rocks in Trans-Pecos Texas, it is improbable that major strike- slip displacement occurred in the region after the beginning of the Permian Period. ThUS, the evidence necessary to demonstrate wrench faulting along the Texas Lineament must be in rock older than Permian." Such is the evidence that Lutton (1958, p. 29) found when he stated, "The cataclasite and dragged foliation of the Pre cambrian rock near the Sawmill Canyon fault suggest that the flaw first developed at that time, as a right-lateral wrench." 94 ADDITIONAL REFERENC ES Lutton, R. J., 1958, Some Structural Features in Southern Arizona : Univ. Arizona unpub. M.S . Thesis, 138 p. Muehlberger, W. R., and M. A. Wiley, 1970, The Texas Lineament, in The Geologic Framework of the Chihuahua Tectonic Belt: Wes t Texas Geol. Society and the Univ . of Texas at Austin Symposium, Midland, Texas, Nov . 6- 8, p. 8-15 . Poole, F . G., D. L. Baars, H. Drewes, P . T. Hayes, K. B. Ketner, E. D. McKee, C. Teichert, and J . S. Williams, 1967, De vonian of the Southwestern United States, in Oswa ld, D. H., ed., Internat. Symposium on the Devonian System, Calgary, Alberta, Sept. 1967 : Calgary, Alberta Soc. Petroleum Geologist, v. 1, p. 879- 912. Sales, J. K., 1968, Cordilleran Foreland Deformation: Amer. Assoc. Petroleum Geologists Bull., v. 52, n. 10, p. 2016- 2044. Titley, S. R., manuscript in preparation, Mesozoic Stratigraphic Paleotectonic Environment of Southwestern North American Porphyry Copper Deposits .