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Middle Miocene to Oligocene volcanic rocks

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)
State Arizona
Name Middle Miocene to Oligocene volcanic rocks
Geologic age Oligocene to Middle Miocene
Primary rock type dacite
Secondary rock type rhyolite
Other rock types andesite; basalt; porphyry; diorite; granite; granodiorite; latite; trachybasalt; trachyte; conglomerate; sandstone; sedimentary breccia; serpentinite
Lithologic constituents
Minor
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow)
Igneous > Volcanic > Felsic-volcanic > Dacite (Flow)
Igneous > Volcanic > Felsic-volcanic > Dacite (Pyroclastic)
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Flow)
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic)
Incidental
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Igneous > Volcanic > Mafic-volcanic > Basalt (Pyroclastic)
Igneous > Volcanic > Mafic-volcanic > Basalt (Volcaniclastic)
Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow)
Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Pyroclastic)
Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Volcaniclastic)
Igneous > Volcanic > Mafic-volcanic > Andesite (Pyroclastic)
Igneous > Volcanic > Mafic-volcanic > Andesite (Volcaniclastic)
Igneous > Volcanic > Felsic-volcanic > Dacite (Volcaniclastic)
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Volcaniclastic)
Igneous > Volcanic > Alkalic-volcanic > Basanite (Flow)
Igneous > Volcanic > Alkalic-volcanic > Basanite (Pyroclastic)
Igneous > Volcanic > Alkalic-volcanic > Basanite (Volcaniclastic)
Igneous > Volcanic > Alkalic-volcanic > Foidite (Flow)including leucitite
Igneous > Volcanic > Alkalic-volcanic > Foidite (Pyroclastic)including leucitite
Igneous > Volcanic > Alkalic-volcanic > Foidite (Volcaniclastic)including leucitite
Igneous > Volcanic > Felsic-volcanic > Latite (Flow)
Igneous > Volcanic > Felsic-volcanic > Latite (Pyroclastic)
Igneous > Volcanic > Felsic-volcanic > Latite (Volcaniclastic)
Igneous > Volcanic > Felsic-volcanic > Trachyte (Flow)
Igneous > Volcanic > Felsic-volcanic > Trachyte (Pyroclastic)
Igneous > Volcanic > Felsic-volcanic > Trachyte (Volcaniclastic)
Igneous > Volcanic > Ultramafic > Picrite (Flow)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basalt (Dike or sill)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basalt (Dome)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basalt (Stock or pipe)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basaltic-andesite (Dike or sill)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basaltic-andesite (Dome)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basaltic-andesite (Stock or pipe)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-andesite (Dike or sill)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-andesite (Dome)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-andesite (Stock or pipe)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-mafic-alkaline (Dike or sill)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-mafic-alkaline (Dome)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-mafic-alkaline (Stock or pipe)
Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-dacite (Dike or sill)
Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-dacite (Dome)
Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-dacite (Stock or pipe)
Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-rhyolite (Dike or sill)
Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-rhyolite (Dome)
Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-rhyolite (Stock or pipe)
Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-latite (Dike or sill)
Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-latite (Stock or pipe)
Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-trachyte (Dike or sill)
Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-trachyte (Stock or pipe)
Igneous > Volcanic > Ultramafic > Picrite (Flow)
Igneous > Hypabyssal > Lamprophyre (Dike or sill)including al”nite, katungite, minette, monchiquite, sedimentary serpentinized ultramafic breccia, shonkinite, vogesite.
Igneous > Plutonic > Dioritic > Diorite (Dike or sill)
Igneous > Plutonic > Dioritic > Quartz-diorite (Dike or sill)
Igneous > Plutonic > Dioritic > Quartz-monzodiorite (Dike or sill)
Igneous > Plutonic > Granitic > Alkali-feldspar-granite (Dike or sill)
Igneous > Plutonic > Granitic > Granite (Dike or sill)
Igneous > Plutonic > Granitic > Granodiorite (Dike or sill)
Igneous > Plutonic > Granitic > Leucocratic-granitic > Aplite (Dike or sill)
Igneous > Plutonic > Granitic > Leucocratic-granitic > Pegmatite (Dike or sill)
Igneous > Plutonic > Syenitic > Monzonite (Dike or sill)
Igneous > Plutonic > Syenitic > Syenite (Dike or sill)
Igneous > Plutonic > Ultramafic > Hornblendite (Dike or sill)
Igneous > Plutonic > Dioritic > Monzodiorite (Dike or sill)
Igneous > Plutonic > Syenitic > Quartz-monzonite (Dike or sill)
Igneous > Plutonic > Dioritic > Diorite (Stock or pipe)
Igneous > Plutonic > Dioritic > Quartz-diorite (Stock or pipe)
Igneous > Plutonic > Dioritic > Quartz-monzodiorite (Stock or pipe)
Igneous > Plutonic > Granitic > Alkali-feldspar-granite (Stock or pipe)
Igneous > Plutonic > Granitic > Granite (Stock or pipe)
Igneous > Plutonic > Granitic > Granodiorite (Stock or pipe)
Igneous > Plutonic > Granitic > Leucocratic-granitic (Stock or pipe)
Igneous > Plutonic > Granitic > Leucocratic-granitic (Stock or pipe)
Igneous > Plutonic > Syenitic > Monzonite (Stock or pipe)
Igneous > Plutonic > Syenitic > Syenite (Stock or pipe)
Igneous > Plutonic > Ultramafic > Hornblendite (Stock or pipe)
Igneous > Plutonic > Dioritic > Monzodiorite (Stock or pipe)
Igneous > Plutonic > Syenitic > Quartz-monzonite (Stock or pipe)
Sedimentary > Clastic > Conglomerate (Bed)
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Clastic > Sedimentary-breccia (Bed)
Sedimentary > Clastic > Siltstone (Bed)
Map references
Richard, S. M., Reynolds, S.J., Spencer, J. E., and Pearthree, P. A., 2000, Geologic Map of Arizona: Arizona Geological Survey Map 35, 1 sheet, scale 1:1,000,000.
Unit references
Richard, S. M., Reynolds, S.J., Spencer, J. E., and Pearthree, P. A., 2000, Geologic Map of Arizona: Arizona Geological Survey Map 35, 1 sheet, scale 1:1,000,000.
Nealey, L.D., and Sheridan, M.F., 1989, Post-Laramide volcanic rocks of Arizona and northern Sonora, Mexico, and their inclusions, in Jenney, J.P., and Reynolds, S.J., editors, Geologic evolution of Arizona: Arizona Geological Society Diges
Spencer, J.E., and Reynolds, S.J., 1989, Middle Tertiary tectonics of Arizona and adjacent areas, in Jenney, J.P., and Reynolds, S.J., editors, Geologic evolution of Arizona: Arizona Geological Society Digest 17, p. 539-574.
Counties Apache - Cochise - Gila - Graham - Greenlee - La Paz - Maricopa - Mohave - Navajo - Pima - Pinal - Santa Cruz - Yavapai - Yuma