428 



STRUCTURAL GEOLOGY OF NORTH AMERICA 





ARTILLERY MTN 

 LASKEY a WEBBER 



AJO DISTRICT 



eiLLULr 



CHRISTMAS 



DISTRICT 



C.R. ROSS 



TUCSON MTS. 

 BROWN 



DRAGOON MTS. 

 GILLULY 



SANTA RITA 

 DISTRICT, Nil. 

 PAIGE a SPENCER 



QUATERNARY 



5 





I 





I 





8 



Uj 









8 





BASALT t 



FAULTING 



FAULTING 



BASALT 



BASALT NEAR 8I5BEE 



BASALT 



UPPER 

 TERTIARY 



CONGLOMERATE 



BATAMOTE 

 ANOESITE 



GILA CONGL 



GILA CONGL 



GILA(f) CONCL. 



% 

 kl 





* 



ki 





I 





BASALT AMD 

 FANGLOMERATE 



CHILD S 

 LATITE 



BLOCK 

 FAULTING 



DANIELS 

 CONGLOMERATE, 



PEARCE VOLS. 

 S VOLCANICS 



SEDIMENTS 

 AND 

 VOLCANICS 



RMYOLITE A MO 

 ANOESITE 



SNEAO 

 ANOESITE 



AJO VOLCANICS 



BLOCK 

 FAULTING j 



LOWER 

 TERTIARY 



LAVAS 



* 





LOCOMOTIVE 

 FANGLOMERATE 



a 





ft 





ft 

 Q 



6 





i 











CONGL. ARKOSE. 

 SS. SH. LS , 



CORNELIA 

 OTZ MONZONITE 



WHITE TAIL CONGL. 



INTRUSIONS 



INTRUSIONS 



INTRUSIONS AND 

 ANOESITE BRECCIA 



UPPER 

 CRETACEOUS 



UPLIFT , 



f 



. INTRUSIONS '^ 



K. FOLDING s^ 



VOLCANICS AND 



SEDIMENTS 



THRUSTING 



THRUSTING , 



* 



* 



LIMES 

 MIMOR 

 or SMA 



TONE. 

 AMOUNT 



IE AND 



A MOLE FM. 



BRONCO VOLCANICS 

 UPPER CRET NEARBY 



COLORADO SH. 

 BEARTOOTH OTZ. 



RECREATION FM. 



BROAD FOLDING 



LOWER 

 CRETACEOUS 



CONCENTRATOR 

 VOLCANICS 



UPLIFT 



- VOLCANICS, 

 CHIEFLY 

 ANOESITE 



CINTURA FM. 

 MURAL LS 

 MO RITA FM. 

 GLANCE CONGL. 



ft 





* 



PENN. 

 MISS 

 DEV. 



SEDS. 

 SEDS. 

 SEDS 



JURASSIC 

 MD 



TRIASSIC 



CHICO SHUNIE 



OUARTZ 



MONZONITE 



UPLIFT 





INTRUSIONS 



t 



Vu 



PALEOZOIC 



HORNFELS 



PERM. SEDS. 

 PENN. SEDS. 



MISS. SEDS. 



DEV. SEDS. 



CAMB. SEDS. 



\ FOLDING / 

 PERM SEDS 

 PENN. SEDS. 

 MISS SEDS. 

 DEV. SEDS. 



CAMB. SEDS 



PERM. SEDS. 

 PENN. SEDS. . 

 MISS. SEDS. 

 DEV. SEDS. 



o. a S. SEDS. 

 CAMB. SEDS. 



IM PART META- 

 MORPHOSED 



DIABASE . 

 CAMB. SEDS. 



PRECAMBRIAN 



PRESENT 



CARDIGAN GNEISS 



PINAL SCHIST 





PINAL SCHIST 





Fig. 27.2. Comparative histories of districts in the Mountain Region and Sonoran Desert of 

 Arizona. The question marks indicate uncertainty of age assignments, but the sequence of 

 events is fairly secure. 



orogeny, Laramide orogeny, and Basin and Range orogeny are not used 

 by authors of some of the most authoritative works. Where used in this 

 chapter the attempt is made to make clear the uncertainties involved. 



MESOZOIC AND CENOZOIC GEOLOGY OF SOUTHEASTERN ARIZONA 



The ranges of southeastern Arizona (Fig. 27.4) contain Paleozoic strata 

 representative of the Cambrian, Devonian, Mississippian, Pennsylvanian, 

 and Permian periods, and also a thick succession of Lower and Upper 



Cretaceous formations. These either do not occur or occur in limited or 

 altered form in other parts of the Mountain and Desert regions, and hence, 

 the nature of crustal deformation and igneous activity is better recorded 

 and deciphered in southeastern Arizona than in the south-central or 

 southwestern part of the state. It is best, therefore, to refer to this region 

 first for an understanding of the Mesozoic and Cenozoic geology before 

 turning to the other areas. 



The Paleozoic section including Permian beds described for the Bisbee 

 district in Fig. 27.3, is characteristic of southeastern Arizona and adjacent 

 New Mexico. These beds were fairly sharply folded some time after the 

 Permian and before the deposition of the overlying Lower Cretaceous beds 

 ( Bisbee group ) . Examples of the folds, thrusts, and unconformable rela- 

 tions are shown in Fig. 27.5 and 27.6. After the folding and faulting and 

 before the deposition of the basal Glance conglomerate of the Bisbee 

 group a number of plutons were intruded including the Gleeson quartz 

 monzonite, the Copper Belle monzonite porphyry, the Turquoise granite, 

 the Juniper Flat granite, and the Cochise Peak quartz monzonite of the 

 Dragoon and Mule mountains (Gilluly, 1956). 



The Mexican geosyncline extended nordiwestward into southeastern 

 Arizona and southwestern New Mexico, and in the Bisbee district the 

 basal beds of Comanche age are conglomerates (Glance conglomerate) 

 which range up to 500 feet thick. Overlying sandstones, shales, and lime- 

 stones attain great thickness, estimates of which range from 5000 to 18,000 

 feet. Fossils collected from the Mural limestone, about 2500 feet above the 

 base of the Comanche series, are Trinity in age. At a number of other 

 localities in southeastern Arizona, such as Tombstone and in the Hua- 

 chuca, Patagonia, Oro Blanco, Baboquivari, Sierrita, Tucson, Santa Rita, 

 Empire, and Whetstone Mountains, masses of sediments, presumable 

 Comanchean, rest unconf ormably upon Paleozoic or older rocks ( Ransome, 

 1933). See the cross sections of Fig. 27.6. In places a deeply dissected 

 surface was buried by the Lower Cretaceous sediments. The intrusive 

 rocks had been exposed in this erosion cycle (Gilluly, 1956). 



If the correlations of the table, Fig. 27.2 are correct, then the Lower 

 Cretaceous Mexican geosyncline was continued to the northwest chiefly 

 by a volcanic fill. The volcanic series of the Tucson Mountains ( Brown, 



