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Mineral Resources > Online Spatial Data > Geology > by state > Arizona Geology

Geologic units in Mohave county, Arizona

[Additional scientific data in this geographic area]

Holocene to middle Pliocene basaltic rocks (Middle Pliocene to Holocene) at surface, covers 3 % of this area

Mostly dark-colored basaltic lava and cinders young enough that some original volcanic landforms are still apparent. Includes a small amount of andesite, dacite, and rhyolite. Rocks of this map unit are largely restricted to six areas widely distributed in Arizona: San Francisco and Uinkaret volcanic fields in northern Arizona (0-4 Ma); Springerville (0-4 Ma) and San Carlos (0-2 Ma) volcanic fields in east-central Arizona; and San Bernardino (0-1 Ma) and Sentinel (1-4 Ma) volcanic fields in southern Arizona. Rocks of this unit are also present in the extreme southwestern part of Arizona where they were erupted at the edge of the Pinacate volcanic field (0-2 Ma) in northwestern Sonora. (0-4 Ma)

Lithology: alkaline basalt; basalt; andesite; hawaiite; trachyte; alkali rhyolite; dacite; latite; rhyolite; tholeiite; trachyandesite; conglomerate; sandstone; sedimentary breccia

Paleozoic sedimentary rocks (Paleozoic) at surface, covers < 0.1 % of this area

Undivided Paleozoic limestone, dolostone, quartzite, shale, and related sedimentary rocks. (248-544 Ma)

Lithology: limestone; sandstone; marble; gneiss; granofels; schist; gypsum; phyllite; quartzite; quartz-feldspar schist; schist; pelitic schist

Pliocene to middle Miocene volcanic rocks (Middle Miocene to Pliocene) at surface, covers 0.4 % of this area

Rhyolite to andesite deposited as lava flows and related rocks associated with basaltic rocks of map units Tby and Tb. (2-12 Ma)

Lithology: rhyolite; dacite; andesite; alkaline basalt; basalt; conglomerate; sandstone; sedimentary breccia

Intrusive rocks (Late Cretaceous to Middle Miocene) at surface, covers < 0.1 % of this area

INTRUSIVE ROCKS-Aphanitic, porphyritic, and coarsely granular rocks ranging in composition from diorite to granite. Clark County

Lithology: alkali-granite (alaskite); granite; granodiorite; tonalite; diorite; peraluminous granite

Jurassic and Triassic sedimentary and volcanic rocks (Triassic and Jurassic) at surface, covers < 0.1 % of this area

Undivided massive quartz-feldspar porphyry of the Jurassic Planet Volcanics, quartz-rich metasandstone of the Jurassic Vampire Formation, and quartzite, phyllite, and fine grained, variably calcareous metasiltstone of the Triassic Buckskin Formation; exposed primarily in the Buckskin and Rawhide Mountains of western Arizona. This unit also includes sandstone and conglomerate beneath Jurassic volcanic rocks in the central Dome Rock Mountains. (160-240 Ma)

Lithology: rhyolite; sandstone; phyllite; metarhyolite; orthoquartzite; rhyolite; conglomerate

Shinarump Conglomerate Member, Chinle Formation (Late Triassic) at surface, covers 1 % of this area

Basal conglomerate and pebbly sandstone of the Chinle Formation is relatively resistant to erosion and forms extensive benches in some parts of the Colorado Plateau. (210-230 Ma)

Lithology: conglomerate; sandstone; siltstone; claystone

Middle Miocene to Oligocene volcanic and sedimentary rocks, undivided (Oligocene to Middle Miocene) at surface, covers 0.7 % of this area

Sequences of diverse volcanic rocks with abundant interbedded sedimentary rocks. (11-32 Ma)

Lithology: andesite; basalt; conglomerate; dacite; rhyolite; sandstone; sedimentary breccia; limestone; siltstone

Pliocene to late Miocene basaltic rocks (Late Miocene to Pliocene) at surface, covers 2 % of this area

Mostly dark, inconspicuously flat, low-lying or mesa-forming basalt deposited as lava flows. Rocks included in this unit are located almost entirely in the large volcanic fields south and west of Flagstaff, in smaller fields in northwesternmost Arizona, and in the Hopi Buttes volcanic field on the Navajo and Hopi Indian Reservations north of Holbrook. Original volcanic landforms have been obscured by erosion. (4-8 Ma)

Lithology: basalt; alkaline basalt; tholeiite; claystone; conglomerate; limestone; sandstone; sedimentary breccia; siltstone; tuff; chert; gypsum

Pennsylvanian and Permian sedimentary rocks in southwestern Utah (Pennsylvanian) at surface, covers < 0.1 % of this area

Lithology: dolostone (dolomite); sandstone

Early Tertiary to Late Cretaceous granitic rocks (Late Cretaceous to Early Tertiary) at surface, covers 0.3 % of this area

Porphyritic to equigranular granite to diorite emplaced during the Laramide orogeny. Larger plutons are characteristically medium-grained, biotite +/- hornblende granodiorite to granite. Smaller, shallow-level intrusions are typically porphyritic. Most of the large copper deposits in Arizona are associated with porphyritic granitic rocks of this unit, and are thus named 'porphyry copper deposits'. (50-82 Ma)

Lithology: granodiorite; granite; diorite; porphyry; quartz diorite; aplite; gabbro; pegmatite; skarn

Siltstone, sandstone, limestone, and dolomite (commonly silty or sandy) and gypsum (Early Permian) at surface, covers < 0.1 % of this area

SILTSTONE, SANDSTONE, LIMESTONE, AND DOLOMITE (COMMONLY SILTY OR SANDY), AND GYPSUM (Lower Permian)-Includes units such as Rib Hill Sandstone and Pequop Formation of Steele (1959) in Elko County, Rib Hill Sandstone and Arcturus Formation in White Pine County, Queantoweap Sandstone of NcNair (1951), Hermit Shale, and Coconino Sandstone in Clark and southern Lincoln Counties.

Lithology: sandstone; limestone; shale; siltstone; dolostone (dolomite); evaporite (gypsum); chert; quartzite

Permian sedimentary rocks (Permian) at surface, covers 13 % of this area

Gray to tan, cherty limestone of Kaibab and Toroweap Formations, and underlying white to tan, fine-grained Coconino Sandstone. Limestone was deposited in a shallow sea, and sandstone was deposited in near-shore dunes and beach settings. (270-280 Ma)

Lithology: limestone; sandstone; gypsum; mudstone; dolostone (dolomite); orthoquartzite

Andesite and basalt flows (Early Miocene to Early Pliocene) at surface, covers < 0.1 % of this area

ANDESITE AND BASALT FLOWS-Mostly in about 17 to about 6 m.y. age range. In Humboldt County, locally includes rocks as old as 21 m.y. May include rocks younger than 6 m.y. in places

Lithology: basalt; andesite; shoshonite

Dolomite, limestone, and minor amounts of sandstone and quartzite (Devonian) at surface, covers < 0.1 % of this area

DOLOMITE, LIMESTONE, AND MINOR AMOUNTS OF SANDSTONE AND QUARTZITE-Includes units such as Sevy and Simonson Dolomites, Guilmette and Nevada Formations, and Devils Gate Limestone.

Lithology: dolostone (dolomite); limestone; sandstone; quartzite; conglomerate; shale; chert

Moenkopi Formation (Early and Middle(?) Triassic) at surface, covers 6 % of this area

Dark red sandstone and mudstone; includes gypsum beds in northwestern Arizona; deposited on a low-relief coastal plain. (230-245 Ma)

Lithology: mudstone; sandstone; orthoquartzite; siltstone; arenite; claystone; conglomerate; dolostone (dolomite); gypsum; limestone; sedimentary breccia

Chinle Formation (Late Triassic) at surface, covers 0.7 % of this area

Colorful mudstone, such as in the Painted Desert, and less abundant lenses of sandstone and conglomerate, deposited by a large river system. This unit typically is eroded into badlands topography and contains clays that are prone to shrinking and swelling. (210-230 Ma)

Lithology: mudstone; sandstone; calcarenite; conglomerate; limestone; siltstone

Middle Miocene to Oligocene volcanic rocks (Oligocene to Middle Miocene) at surface, covers 7 % of this area

Lava, tuff, fine-grained intrusive rock, and diverse pyroclastic rocks. These compositionally variable volcanic rocks include basalt, andesite, dacite, and rhyolite. Thick felsic volcanic sequences form prominent cliffs and range fronts in the Black (Mohave County), Superstition, Kofa, Eagletail, Galiuro, and Chiricahua Mountains. This unit includes regionally extensive ash-flow tuffs, such as the Peach Springs tuff of northwestern Arizona and the Apache Leap tuff east of Phoenix. Most volcanic rocks are 20-30 Ma in southeastern Arizona and 15 to 25 Ma in central and western Arizona, but this unit includes some late Eocene rocks near the New Mexico border in east-central Arizona. (11-38 Ma)

Lithology: dacite; rhyolite; andesite; basalt; porphyry; diorite; granite; granodiorite; latite; trachybasalt; trachyte; conglomerate; sandstone; sedimentary breccia; serpentinite

Triassic (2) sedimentary rocks in southwestern Utah (Late Triassic) at surface, covers < 0.1 % of this area

Lithology: mudstone; conglomerate; siltstone

Early Proterozoic metasedimentary rocks (Early Proterozoic) at surface, covers 0.5 % of this area

Metasedimentary rocks, mostly derived from sandstone and shale, with minor conglomerate and carbonate rock. Includes quartz-rich, mostly nonvolcanic Pinal Schist in southeastern Arizona and variably volcanic-lithic sedimentary rocks in the Yavapai and Tonto Basin supergroups in central Arizona. (1600-1800 Ma)

Lithology: phyllite; schist; quartzite; argillite; arkose; sandstone; iron formation; conglomerate; sandstone; gneiss; granofels; graywacke; mudstone; hornfels; metaconglomerate; migmatite; orthoquartzite; rhyolite; shale; siltstone; slate; wacke; diorite; amphibolite; greenschist; limestone; metarhyolite; diorite

Cherty limestone and sparse dolomite, shale, and sandstone (Permian) at surface, covers < 0.1 % of this area

CHERTY LIMESTONE AND SPARSE DOLOMITE, SHALE, AND SANDSTONE (Lower and Upper Permian)-Includes units such as Park City Group and equivalent rocks in northern Nevada and Toroweap Formation and Kaibab Limestone in southern Nevada

Lithology: limestone; shale; dolostone (dolomite); sandstone; siltstone; chert; conglomerate; phosphorite; evaporite

Holocene surficial deposits (Holocene) at surface, covers 0.9 % of this area

Unconsolidated deposits associated with modern fluvial systems. This unit consists primarily of fine-grained, well-sorted sediment on alluvial plains, but also includes gravelly channel, terrace, and alluvial fan deposits on middle and upper piedmonts. (0-10 ka)

Lithology: sand; gravel; mud; silt

Horse Spring Formation (Late Oligocene to Middle Miocene) at surface, covers < 0.1 % of this area

HORSE SPRING FORMATION-Tuffaceous sedimentary rocks, southern Nevada

Lithology: limestone; sandstone; dolostone (dolomite); mudstone; siltstone; evaporite; tuff; lava flow; felsic volcanic rock; intermediate volcanic rock; mafic volcanic rock

Permian (1) sedimentary rocks in southwestern Utah (Early Permian) at surface, covers < 0.1 % of this area

Lithology: sandstone; dolostone (dolomite); fine-grained mixed clastic

Early Proterozoic metamorphic rocks (Early Proterozoic) at surface, covers 4 % of this area

Undivided metasedimentary, metavolcanic, and gneissic rocks. (1600-1800 Ma)

Lithology: schist; gneiss; amphibolite; granofels; calc-silicate schist; granulite; greenschist; marble; diorite; gabbro; granite; granodiorite; metasedimentary rock; migmatite; phyllite; quartzite

Late to middle Miocene basaltic rocks (Middle to Late Miocene) at surface, covers 2 % of this area

Mostly dark, mesa-forming basalt deposited as lava flows. Rocks of this unit are widely exposed south of Camp Verde (Hickey Formation basalts), in the Mohon Mountains north of Bagdad, "The Mesa" east of Parker, and at other scattered locations in western Arizona. Rocks of this unit were not tilted by middle-Tertiary normal faulting except in a narrow belt from north of Phoenix to the northwest corner of the state. (8-16 Ma)

Lithology: basalt; alkaline basalt; hawaiite; tholeiite; andesite; dacite; rhyolite; trachyandesite; trachybasalt; conglomerate; sandstone; sedimentary breccia

Alluvial deposits (Quaternary) at surface, covers < 0.1 % of this area

ALLUVIAL DEPOSITS-Locally includes beach and sand dune deposits

Lithology: alluvium; mass wasting; dune sand; lake or marine deposit (non-glacial)

Tertiary nonmarine rocks, undivided (Paleocene to Pliocene) at surface, covers < 0.1 % of this area

Undivided Tertiary sandstone, shale, conglomerate, breccia, and ancient lake deposits.

Lithology: conglomerate; sandstone; sedimentary breccia; volcanic rock (aphanitic); mudstone; limestone; siltstone

Quaternary alluvium and colluvium (Quaternary) at surface, covers < 0.1 % of this area

Lithology: alluvium; colluvium

Early Pleistocene to late Miocene basin deposits (Late Pliocene to Early Pleistocene) at surface, covers 1 % of this area

Poorly sorted, variably consolidated gravel and sand that range widely in age. These sediments are generally light gray or tan. This unit is generally mapped in areas of deep late Cenozoic stream incision and landscape degradation where thin Quaternary deposits (map units Qy, Qm, Qo) discontinuously blanket older deposits (map units Tsy or Tsm) and the two cannot be differentiated at the scale of this map. (0.75-10 Ma)

Lithology: gravel; sand; mud; silt

Middle Miocene to Oligocene granitic rocks (Oligocene to Middle Miocene) at surface, covers 0.7 % of this area

Granite to diorite representing solidified magma chambers that were the likely source of overlying and nearby volcanic rocks of map unit Tv. The granitic rocks are typically equigranular and fine- to medium-grained. (14-26 Ma)

Lithology: granodiorite; granite; diorite; porphyry; quartz diorite; aplite; gabbro; pegmatite; hornblendite; hornfels; gabbro

Middle Miocene to Oligocene sedimentary rocks (Oligocene to Middle Miocene) at surface, covers 1 % of this area

Con-glomerate, sandstone, mudstone, limestone, and rock-avalanche breccia (sheet-like deposits of crushed rock) deposited and tilted during widespread normal faulting and basin development. Sediments, mostly conglomerate and sandstone, are commonly medium to dark brown, reddish brown, or brownish gray; younger strata are generally lighter colors. Most deposits are 20 to 30 Ma in southeastern Arizona and 15 to 25 Ma in central and western Arizona. (11-32 Ma)

Lithology: conglomerate; sandstone; sedimentary breccia; siltstone; limestone; mudstone; landslide

Mississippian, Devonian, and Cambrian sedimentary rocks (Cambrian, Devonian, and Mississippian) at surface, covers 7 % of this area

Brown to dark gray sandstone grades upward into green and gray shale, overlain by light to medium gray or tan limestone and dolostone. This unit includes the Tapeats Sandstone, Bright Angel Shale, Muav Limestone, Temple Butte Formation and Redwall Limestone in northern Arizona, and the Bolsa Quartzite, Abrigo Formation, Martin Formation, and Escabrosa Limestone in southern Arizona. These rocks record intermittent sea-level rise and inundation in early Paleozoic time. (330-540 Ma)

Lithology: sandstone; siltstone; mudstone; shale; chert; dolostone (dolomite); limestone; conglomerate; arkose; orthoquartzite

Pliocene and Quaternary alluvial material (Pliocene to Quaternary) at surface, covers < 0.1 % of this area

Lithology: alluvium

Permian (2) sedimentary rocks in southwestern Utah (Early Permian) at surface, covers < 0.1 % of this area

Lithology: limestone; evaporite; chert

Quaternary surficial deposits, undivided (Quaternary) at surface, covers 16 % of this area

Unconsolidated to strongly consolidated alluvial and eolian deposits. This unit includes: coarse, poorly sorted alluvial fan and terrace deposits on middle and upper piedmonts and along large drainages; sand, silt and clay on alluvial plains and playas; and wind-blown sand deposits. (0-2 Ma)

Lithology: sand; gravel; mud; silt

Andesite and related rocks of intermediate composition (Late Miocene to Middle Miocene) at surface, covers < 0.1 % of this area

ANDESITE AND RELATED ROCKS OF INTERMEDIATE COMPOSITION-Flows and breccias

Lithology: andesite; latite; trachyte; dacite

Triassic (1) sedimentary rocks in Salt southwestern Utah (Early Triassic) at surface, covers < 0.1 % of this area

Lithology: mudstone; siltstone; limestone; sandstone; conglomerate; evaporite

Quaternary alluvium and marine deposits (Pliocene to Holocene) at surface, covers < 0.1 % of this area

Alluvium, lake, playa, and terrace deposits; unconsolidated and semi-consolidated. Mostly nonmarine, but includes marine deposits near the coast.

Lithology: alluvium; terrace; lake or marine deposit (non-glacial)

Middle Miocene to Oligocene shallow intrusions (Oligocene to Middle Miocene) at surface, covers < 0.1 % of this area

Generally very fine-grained, porphyritic rhyolite to dacite in small, irregular-shaped bodies formed as subvolcanic intrusions in volcanic fields of southern and western Arizona, or in concentrated zones of dikes in the Mohave and Black Mountains of northwestern Arizona. The unit consists of mafic tuff, breccia and shallow intrusions at Buell Park in northeastern Arizona. (14-35 Ma)

Lithology: dacite; rhyolite; porphyry; rhyolite; conglomerate; sandstone; sedimentary breccia

Aztec Sandstone (Early Jurassic) at surface, covers < 0.1 % of this area

AZTEC SANDSTONE (Triassic? And Jurassic)-Friable fine- to medium-grained sandstone with conspicuous large-scale cross strata; considered eolian. Age based on correlation with Navajo Sandstone

Lithology: sandstone

Permian to Pennsylvanian sedimentary rocks (Pennsylvanian to Permian) at surface, covers 6 % of this area

Interbedded sandstone, shale, and limestone usually characterized by ledgy outcrops. Orange to reddish sandstone forms cliffs near Sedona. This unit includes Supai Group and Hermit Shale in northern Arizona and Naco Group in southern Arizona. It was deposited in coastal-plain to shallow-marine settings during time of variable and changing sea level. Rocks of this map unit in southern Arizona may be in part equivalent to Permian rocks of map unit P in central and northern Arizona. (280-310 Ma)

Lithology: sandstone; siltstone; gypsum; mudstone; orthoquartzite; siltstone; sedimentary breccia; dolostone (dolomite); limestone; conglomerate; shale; calcarenite; evaporite

Early Proterozoic metavolcanic rocks (Early Proterozoic) at surface, covers < 0.1 % of this area

Weakly to strongly metamorphosed volcanic rocks. Protoliths include basalt, andesite, dacite, and rhyolite deposited as lava or tuff, related sedimentary rock, and shallow intrusive rock. These rocks, widely exposed in several belts in central Arizona, include metavolcanic rocks in the Yavapai and Tonto Basin supergroups. (1650 to 1800 Ma)

Lithology: greenstone; intermediate metavolcanic rock; amphibolite; andesite; basalt; chert; conglomerate; dacite; diabase; diorite; gabbro; gneiss; greenschist; granite; granodiorite; graywacke; felsic metavolcanic rock; metarhyolite; gabbro; migmatite; phyllite; quartz diorite; quartzite; rhyolite; volcanic breccia (agglomerate); schist; siltstone; sandstone; serpentinite; iron formation

Early Proterozoic granitic rocks (Early Proterozoic) at surface, covers 8 % of this area

Wide variety of granitic rocks, including granite, granodiorite, tonalite, quartz diorite, diorite, and gabbro. These rocks commonly are characterized by steep, northeast-striking foliation. (1600-1800 Ma)

Lithology: granodiorite; granite; diabase; diorite; gabbro; pegmatite; quartz diorite; tonalite; anorthosite; gneiss; gabbro; greisen; migmatite; porphyry; pyroxenite; rhyolite; schist; trondhjemite

Limestone and minor amounts of dolomite and shale (Mississippian) at surface, covers < 0.1 % of this area

LIMESTONE AND MINOR AMOUNTS OF DOLOMITE AND SHALE-Includes units such as Rogers Spring and Monte Cristo Limestones

Lithology: limestone; dolostone (dolomite); chert; shale; sandstone

Granitic rocks (Middle Proterozoic) at surface, covers < 0.1 % of this area

GRANITIC ROCKS-Porphyritic rapakivi granite.

Lithology: granite

Pliocene to middle Miocene deposits (Middle Miocene to Pliocene) at surface, covers 8 % of this area

Moderately to strongly consolidated conglomerate and sandstone deposited in basins during and after late Tertiary faulting. Includes lesser amounts of mudstone, siltstone, limestone, and gypsum. These deposits are generally light gray or tan. They commonly form high rounded hills and ridges in modern basins, and locally form prominent bluffs. Deposits of this unit are widely exposed in the dissected basins of southeastern and central Arizona. (2-16 Ma)

Lithology: conglomerate; sandstone; gravel; sand; gypsum; limestone; mudstone; siltstone

Early Pleistocene to latest Pliocene surficial deposits (Late Pliocene to Early Pleistocene) at surface, covers 5 % of this area

Coarse relict alluvial fan deposits that form rounded ridges or flat, isolated surfaces that are moderately to deeply incised by streams. These deposits are generally topographically high and have undergone substantial erosion. Deposits are moderately to strongly consolidated, and commonly contain coarser grained sediment than younger deposits in the same area. (0.75-3 Ma)

Lithology: gravel; sand; mud; silt

Middle Proterozoic granitic rocks (Middle Proterozoic) at surface, covers 2 % of this area

Mostly porphyritic biotite granite with large microcline phenocrysts, with local fine-grained border phases and aplite. Associated pegmatite and quartz veins are rare. This unit forms large plutons, including the Oracle Granite, Ruin Granite, granite in the Pinnacle Peak - Carefree area northeast of Phoenix, and several bodies west of Prescott. (1400-1450 Ma)

Lithology: granite; granodiorite; quartz diorite; quartz monzonite; pegmatite; aplite

Triassic and Jurassic sedimentary rocks in southwestern Utah (Early to Middle Jurassic) at surface, covers < 0.1 % of this area

Lithology: sandstone; siltstone; mudstone; limestone

Holocene river alluvium (Holocene) at surface, covers 0.4 % of this area

Unconsolidated to weakly consolidated sand and gravel in river channels and sand, silt, and clay on floodplains. Also includes young terrace deposits fringing floodplains. (0-10 ka)

Lithology: sand; gravel; mud; silt

Limestone and sparse dolomite, siltstone, and sandstone (Mississippian to Early Permian) at surface, covers < 0.1 % of this area

LIMESTONE AND SPARSE DOLOMITE, SILTSTONE, AND SANDSTONE-Includes units such as undivided Riepe Spring Limestone of Steele (1960) and Ely Limestone or their equivalent in Elko, White Pine, and northern Lincoln Counties and most of the Bird Spring Formation and Callville Limestone in Clark and southern Lincoln Counties. Includes some stratigraphically higher Permian rocks in Leppy Peak, easternmost Elko County.

Lithology: limestone; sandstone; siltstone; chert; shale; dolostone (dolomite); conglomerate

Limestone and dolomite, locally thick sequences of shale and siltstone (Late Cambrian to Middle Cambrian) at surface, covers < 0.1 % of this area

LIMESTONE AND DOLOMITE, LOCALLY THICK SEQUENCES OF SHALE AND SILTSTONE-Includes units such as Pioche Shale, Eldorado Dolomite, Geddes Limestone, Secret Canyon Shale, Hamburg Dolomite, Dunderberg Shale, and Windfall Formation of northern Nevada and Carrara, Bonanza King, and Nopah Formations of southern Nevada.

Lithology: limestone; dolostone (dolomite); shale; siltstone; sandstone; chert; conglomerate

Tertiary to Early Proterozoic gneissic rocks (Early Proterozoic to Tertiary) at surface, covers 0.2 % of this area

Gneissic rocks with complex histories, typically with well developed, light-colored granitoid layers and dark-colored biotite- and amphibole-rich layers. Protoliths are of Tertiary to Proterozoic age. This unit includes variably mylonitic gneisses in metamorphic core complexes that have been exhumed from middle crustal levels by large-displacement middle Tertiary normal faults, and gneiss exposed at scattered locations near the Colorado River in southwestern Arizona. These rocks are interpreted to record Proterozoic, Mesozoic, and Tertiary metamorphism and deformation. (15-1800 Ma)

Lithology: gneiss; mylonite; pegmatite; schist; aplite; granite; granodiorite

Glen Canyon Group (Early Jurassic) at surface, covers 1 % of this area

Conspicuous red, cross-bedded Wingate Sandstone and the conspicuously cross-bedded, eolian, red to buff Navajo Sandstone form prominent cliffs in northern Arizona. These two sandstone units are separated by variably colored siltstone, silty sandstone, and sandstone of the Kayenta and Moenave Formations. (180-210 Ma)

Lithology: sandstone; mudstone; mudstone; siltstone; orthoquartzite; sandstone

Metamorphic rocks (Early Proterozoic) at surface, covers < 0.1 % of this area

METAMORPHIC ROCKS-Gneiss and schist and lesser amounts of gneissic granite, pyroxenite, hornblendite, migmatite, pegmatite, and marble.

Lithology: gneiss; schist; marble; granite; pyroxenite; hornblendite; migmatite; pegmatite; amphibolite

Tuffaceous sedimentary rocks (Late Eocene to Late Miocene) at surface, covers < 0.1 % of this area

TUFFACEOUS SEDIMENTARY ROCKS-Locally includes minor amounts of tuff

Lithology: sandstone; limestone; siltstone; conglomerate; mudstone; dolostone (dolomite); felsic volcanic rock; intermediate volcanic rock; mafic volcanic rock; tuff

Oligocene to Paleocene[?] sedimentary rocks (Paleocene(?) to Oligocene) at surface, covers 0.2 % of this area

Light colored, weakly to moderately consolidated conglomerate and sandstone deposited largely or entirely before mid-Tertiary volcanism and extensional faulting. Most sediment was deposited by early Cenozoic streams that flowed northeastward onto the Colorado Plateau from areas to the southwest that are now lower in elevation than the Plateau. Sediments of this map unit, other than the Chuska Sandstone in northeasternmost Arizona, are commonly referred to as "rim gravels" because they now rest on or near the Mogollon Rim, which is the southwestern edge of the Colorado Plateau. (30-65 Ma)

Lithology: conglomerate; sandstone; siltstone; limestone; mudstone; basalt

Jurassic volcanic rocks (Jurassic) at surface, covers < 0.1 % of this area

Massive quartz-feldspar porphyry, generally interpreted as thick, welded rhyolitic tuffs, with locally abundant lava, and sandstone and conglomerate derived from volcanic rocks. Rare eolian quartzite units are interbedded in southern Arizona. Includes Ali Molina Formation, Mount Wrightson Formation, part of the Canelo Hills Volcanics, Cobre Ridge tuff, Black Rock volcanics, Planet Volcanics, and equivalent rocks. (160-200 Ma)

Lithology: rhyolite; felsic metavolcanic rock; metarhyolite; conglomerate; dacite; felsic metavolcanic rock; quartz-feldspar schist; sandstone; arenite; arkose; granite; porphyry; meta-conglomerate; orthoquartzite; quartzite