Arizona Geological Survey OFR-09-05 (Empire Ranch Bedrock), v.1.0 110°45' 110°42'30" 110°40' 110°37'30" 524000 525000 526000 527000 528000 529000 530000 531000 532000 533000 534000 535000 BEDROCK GEOLOGIC MAP OF THE NORTHERN PART OF THE EMPIRE " 0 " 3 0 ' 3 2 ' RANCH 7 ½' QUADRANGLE, PIMA 5 2 ° 5 1 ° 3 1 3 COUNTY, ARIZONA by Ferguson, C.A. 0 0 0 0 0 0 6 6

2 2 August 2009 5 5 3 3

Arizona Geological Survey Open-File Report 09-05 (OFR-09-05), version 1.0

Citation for this map: Ferguson, C.A., 2009, Bedrock geologic map of the Northern Part of the Empire Ranch 7 ½' Quadrangle, Pima County, Arizona: Arizona Geological 0 0

0 0 Survey Open-File Report OFR-09-05, scale 1:24,000. 0 0 5 5 2 2 5 5 3 3 Research supported by the U.S. Geological Survey, National Cooperative Geologic Mapping Program, under assistance award number 08HQAG0093. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. 0 0 0 0 0 0 4 4 2 2 5 5 3 3 Map Symbol Descriptions Location Map

63 Mapped area shown in blue  Horizontal bedding  Eutaxitic foliation 15 Inclined bedding 31 Flow foliation 24 Inclined apparent bedding 19 Generic foliation 0 0 0 0

0 0 34 48

3 3 Upright bedding, facing indicators Cleavage 2 2

5 5   3 3 present at this location 39 Flow lineation 56 Overturned bedding  81 12 ÷ Paleocurrent direction determined Intersection lineation from imbricate clasts  5 Slickenline lineation 21 Joint  17 69 ' 0 0 0 ' Minor fault or vein S-fold hinge line 0 0 5 0 °

0 0 

5  1 2 2 ° 2 2 3 1 5 5 3 3 3 10 81  Fault dip  Minor fold hinge line

Accurately located contact Accurately located fault 110°53' 110°45' 110°38' 110°30' ' ' 0 0 ° ° 2 2 3 Approximately located contact Approximately located fault 3 0 0

0 0 Fault concealed beneath 0 0

1 1 Scratch contact 2 2

5 5 surficial units 3 3 CORONA MOUNT FAGAN THE NARROWS Fine-grained felsic dike Monzonitic dike DE TUCSON ' Quartz porphyry dike Marker bed ' 3 3 5 5 ° ° 1 1 3 Mafic dike  Approximately located anticline 3  Approximately located syncline SPRING HELVETIA WATER CANYON 0 0

0 0 EMPIRE RANCH 0 0 0 0 2 2 5 5 3 3 ' ' 5 5 4 4 ° ° 1 1 3 3

MOUNT SONOITA ELGIN WRIGHTSON

524000 525000 526000 527000 528000 529000 530000 531000 532000 533000 534000 535000 ' 110°45' 110°42'30" 110°40' 110°37'30" ' 8 8 3 3 ° ° 1 1 3 SCALE 1:24 000 3 Topographic base from USGS 1:24,000 Quadrangle Series. ^ M 1 0.5 0 1 MILE Seamless basemap generated using iGage All Topo Pro software. N 110°53' 110°45' 110°38' 110°30' 1000 0 1000 2000 3000 4000 5000 6000 7000 FEET Projection Information: 1 0.5 0 1 KILOMETER North American Datum of 1983. 10½º 1000-meter Universal Transverse Mercator grid tics, zone 12, shown in blue. CONTOUR INTERVAL 40 FEET

2007 MAGNETIC NORTH DECLINATION Map Unit Descriptions

Disturbed areas (Holocene) - Areas distrubed by human activity; embackments, dams, Quartz porphyry (Tertiary – Upper Cretaceous) - Felsic porphyry containing 10-30% Solero Group (continued) Bisbee Group (continued) Naco Group (Permian - Pennsylvanian) Naco Group (continued) d dumps. TKq quartz and feldspar phenocrysts (1-3mm), and sparse biotite in a fine-grained light-colored matrix, locally flow-foliated. Forms dikes and sills, and a plug-like stock in Andesite porphyry - Strongly altered andesitic porphyritic rock, possibly also strongly Apache Canyon Formation (Lower Cretaceous) - Arkosic sandstone, mudstone, Rainvalley Formation (Permian) - Medium- to thick-bedded dolostone and limestone Earp Formation (Permian – Pennsylvanian) - A mixed siliciclastic-carbonate unit the northwest corner of the map area. Kai Ka P*e Talus and colluvium (Quaternary) - Talus and colluvium brecciated limestone, and rare pebbly sandstone. The Apache Canyon is distinguished from Pr interbedded with minor quartzose sandstone and siliceous shale. Dolostone is consisting of light reddish brown to light green, thin- to medium-bedded, Qt other units of the Bisbee by its signature lithology; dark, typically laminated, micritic, light to dark gray, weathered light to medium gray, and is locally laminated. planar-laminated mudstone, siltstone, and very fine-grained sandstone, interbedded nonfossiliferous micritic limestone. The limestone, making up as much as 50% of the with subordinate light gray to pinkish gray micritic limestone and skeletal wackestone. Felsic tuff (Tertiary – Upper Cretaceous) - Moderately phenocryst-rich ash-flow tuff Fort Crittenden Formation, Solero Group conglomerate undifferentiated (Upper Limestone is medium to dark gray lime mudstone and wackestone, containing chert TKt formation, occurs in laminae, and thin- to medium-bedded, rarely thick-bedded The siliciclastic components are commonly metamorphosed to light green or containing 10-25% quartz and feldspar phenocrysts with biotite. Tuff contains 5-30% Kfc Cretaceous) - Pebble-cobble conglomerate, pebbly sandstone, sandstone and nodules and brachiopod or pelecypod fragments. Fine- to medium-grained quartz sequences of amalgamated laminated to thin-laminated black limestone interleaved orange-pink hornfels. The limestone is locally dolomitic and is commonly Active Alluvium (Holocene) - Active alluvium lithic lapilli and is closely associated with a plug of the quartz porphyry (TKq) in the mudstone, volcaniclastic breccia and minor, thin volcanic flows and tephra layers. sandstone is light gray to yellowish, is weathered light orange-pink, and forms Qa with dark mudstone and shale. Sandstone occurs in thin- to thick-bedded units that metamorphosed to fine-grained marble. 90-110m thick. northwest corner of the map area. Conglomerate ranges from well-rounded and clast-supported with clasts dominated intervals up to 3 m thick. Sandstone locally exhibits bimodal grain size (very-fine- display bed-scale cross-stratification, but also, and more commonly, graded beds, by quartz sandstone, and arkosic sandstone, with lesser argillite, limestone, and and medium-grained), and some intervals display flaser bedding. ~100m thick. either massive or plane-bedded stratified. Ripple-laminated sequences are common granitoid to felsic to intermediate volcaniclastic breccia with angular to sub-rounded Fine-grained felsic porphyry (Tertiary – Upper Cretaceous) - Fine-grained porphyry in individual thin beds and laminae, and as gradational tops to the graded beds. The Horquilla Limestone, Naco Group (Pennsylvanian) - Light gray, thin- to thick-bedded, Older alluvium (Quaternary) - Alluvium in terraces incised more than 3m. TKp clasts. The clast types are present in highly variable amounts, and the assemblages *h Qoa felsic porphyry containing less than 5% feldspar and sparse quartz phenocrysts in a mudstone, which dominates the formation, occurs in sets that range up to 10m thick. Concha Limestone (Permian) - Dark to medium gray, thick- to medium-bedded, cherty limestone with interbeds of dark gray to green silty mudstone and shale that accordingly range from monmict through polymict. In general, the polymict have Pch fine-grained light-colored matrix, typically strongly flow-foliated. Forms dikes and sills. The mudstone is also mostly shale or claystone with sparse silty laminae and thin fossiliferous limestone commonly containing chert nodules 10-30 cm across. Lime become more abundant up-section. 200-300m thick. more rounded clasts, and thinner bed sets. Monomict to oligomict deposits are beds. mudstone and wackestone are predominant, with minor skeletal packstone. Fossils Gila Conglomerate (Miocene) -Boulder-cobble-pebble, clast-supported conglomerate typically massive, commonly matrix-supported, and contain angular to sub-rounded, include brachiopods, gastropods, pelecypods, rugose corals, crinoid columnal Tc Diorite (Tertiary – Upper Cretaceous) - Fine-grained biotite diorite, locally plagioclase and pebbly sandstone. Conglomerate occurs in fairly massive to very thick-bedded units TKd very poorly sorted clasts (silt through boulders). fragments, sponge spicules and echinoid spines. 120-220m thick. with stratification defined by grain-size variations. Clasts are sub-angular to sub- porphyritic. Forms dikes and sills. Willow Canyon Formation (Lower Cretaceous) - Arkosic sandstone, mudstone, Kw rounded, but also range to well-rounded. Assemblages range from monomict to conglomerate. Sandstone occurs in thin- to thick-beds of fine- to coarse-grained, and Bisbee Group (Lower Cretaceous) Sherrer Formation (Permian) - A unit dominated by white to pink, fine-grained, oligomict with a wide variety of possible clasts, all derived from local sources. Clasts, Solero Group (Upper Cretaceous) granule, moderately poorly sorted arkose and lithic arkose. Beds are massive or Ps in general order of abundance are: phenocryst-rich ash-flow tuff, arkosic sandstone, plane-bedded and cross-stratified. The pebbles and cobbles are typically rounded to planar-laminated, quartzose sandstone. The unit is subdivided into lower and upper argillite, quartz sandstone and quartzite, limestone, andesitic volcanics, and two Turney Ranch Formation (Lower Cretaceous) - Quartzose sandstone and well-rounded, but locally sub-angular to sub-rounded. To the south, up to 50% or subdivisions. The lower subdivision (Psl) consists entirely of quartzose sandstone. Rhyolite of Mt Fagan (Upper Cretaceous) - Quartz-feldspar-biotite ash-flow tuff, Kt The upper subdivision (Psu) is marked by medium- to thick-bedded micritic dolostone kinds of granitoid (Proterozoic, and late Cretaceous). Each of these are locally Kr mudstone. This unit consists of alternating sandstone-rich and mudstone-rich more of the clasts are intermediate volcanic or hypabyssal igneous. Mudstone, very abundant. lithic-rich ash-flow tuff, and tuff breccia. The tuff contains 15-30% phenocrysts of sequences on the order of 5-50m. Mudstone-rich intervals are typically red to purple, which makes up more than half of the formation in most areas, is fairly silty with only up to 25 m thick, overlain by more quartz arenite. 100-180m thick. quartz (1-5mm), sanidine (1-4mm), plagioclase (1-3mm) and biotite 1-3mm. The tuff and to a lesser degree green and includes only rare intervals of pure shale or sparse shale or claystone. Its color is dark olive gray except for the lower part which Unit of North Canyon (Miocene Gila Group) - Oligomict to polymict conglomerate. contains abundant lithic-rich zones (mesobreccia) with 10->50% lithic lapilli and Tcu claystone. Pedogenic carbonate as nodules and in discrete, poorly organized beds is deep red. Epitaph Formation (Permian) - A mixed siliciclastic-carbonate unit consisting of white Clasts of arkose and ash-flow tuff dominate in most areas, but this conglomerate also blocks up to several meters. Some of the lithic-rich zones are exceptionally Pe and lenses up to 2m thick is common. Sandstone is quartzose, typically to medium gray, thin- to thick-bedded limestone and dolostone, and thin- to contains clasts of white porphyry (ranging from phenocryst-rich quartz-phyric to coarse-grained with blocks larger, and in some areas much larger than 100s of cross-stratified, and ranges from thin- to thick-bedded, and fine- to coarse-grained. medium-bedded siltstone, mudstone, and fine-grained sandstone. The carbonate feldspar-phenocryst-poor), limestone, quartzite, and granodiorite. meters. Lithic material of three types dominate; arkosic or quartzose sandstone and mafic lava (Lower Cretaceous) - Mafic lava and lava breccia, locally The base of the formation is defined by the fairly abrupt, first appearance of Kwb and siliciclastic components are metamorphosed to fine-grained marble and light mudstone (Bisbee Group), conglomerate and conglomerate mixed with volcanic amygdaloidal. Interbedded with Willow Canyon Formation (Kw). 0-100m thick. Unit of Adobe Tank (Miocene Gila Group) - Monomict to oligomict conglomerate quartzose sandstone (older sandstones are arkosic and lithic-rich). green hornfels. 150-200m thick. Tcl dominated by clasts of arkose (Bisbee Group), and ash-flow tuff (rhyolite of Mt Fagan) breccia (Fort Crittenden Formation), and andesitic lava. in the west. To the east this conglomerate also contains, locally, light-colored granitoid Glance Conglomerate (Lower Cretaceous - Upper Jurassic) - Limestone Shellenburger Formation (Lower Cretaceous) - Arkosic sandstone, mudstone, rare KJg Colina Limestone (Permian) - Medium- to thick-bedded, white to light gray, micritic clasts that match the Empire Mts Granite (Upper Cretaceous). Rhyolite of Mt Fagan megabreccia (Upper Cretaceous) - Zones within the rhylolite Ks pebble-cobble conglomerate, mostly clast-supported and containing a few % quartz pebbly sandstone. Sandstone beds are thin- to thick-bedded, typically massive or Pc limestone. The unit is characterized by tabular beds, creamy white to tan weathered Krz of Mt Fagan consisting of very large (>>1m) lithic blocks with quartz-feldspar-biotite sandstone and argiillite clasts. Older Conglomerate (Miocene - Oligocene) - Pebble-cobble, Rounded to well-rounded weakly plane-bedded or cross-stratified, argillaceous, arkosic to lithic, and fine- to surfaces (locally pinkish gray, rarely medium or dark gray), and lack of Tco ash-flow tuff matrix. Lithic blocks consist mostly of arkosic or quartzose sandstone coarse-grained. Sandstone also occurs in fairly thick, ripple-laminated beds. conglomerate, sub-angular to sub-rounded volcaniclastic pebble-cobble, rare boulder resistant-weathered siliciclastic layers. 80-110 m thick. Arizona Geological Survey and mudstone (Bisbee Group), conglomerate and conglomerate mixed with volcanic Mudstone, making up slightly more than half the formation is almost exclusively dark Gardner Canyon Formation (Jurassic – Triassic) - Red mudstone, arkosic sandstone, conglomerate with sparse well-rounded siliciclastic clasts, mudstone, massive breccia. 416 W. Congress Street, Suite 100 breccia (Fort Crittenden Formation), or andesitic lava (Kaj). olive green. Mudstone is mostly silty with relatively sparse pure shale or claystone J^g limestone, conglomerate, quartz sandstone, and ash-flow tuff. The Gardner Canyon Clasts are nearly identical to those found in the underlying Fort Crittenden with one Tucson, AZ 85701 intervals. Formation is a heterogenous unit dominated by red, and to a lesser degreee green, important and diagnostic exception. White quartz porphyry (TKq) and lesser amounts (520) 770-3500 commonly strongly cleaved mudstone with subordinate, yet abundant arkosic sandstone of phenocryst-poor porphyry (Tp) and ash-flow tuff (Kr) are sparsely present. Andesite lava of Jules Mountain (Upper Cretaceous) - Andesite lava and lava www.azgs.az.gov Kaj beds ranging from fine to granule, and thin- to thick-bedded. Rare felsic ash-flow tuffs breccia containing 5-15% 1-3mm plagioclase, and lesser typically altered <2mm Lower Shellenburger Formation (Lower Cretaceous) - Arkosic sandstone and and/or ash-fall tuff up to 3m thick occur in some areas (Empire Ranch and Mt Fagan mafic phenocrysts. Ksl mudstone capped by a distinctive, resistant bed of oyster packstone limestone unit quadrangles). Pedogenic carbonate lenses and nodules are common within red <5m thick that defines the top of this map unit. Sandstones of this unit are fine- to mudstone, but dark gray, recrystallized, probable packstone-grainstone limestone beds medium-grained arkosic to lithic and argillaceous. Mudstone is mostly silty with up to 30cm thick are also present in some areas. relatively sparse pure shale or claystone intervals. Arizona Geological Survey OFR-09-05 (Empire Ranch Bedrock), v.1.0