Jurassic volcanic rocks

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)
State Arizona
Name Jurassic volcanic rocks
Geologic age Jurassic
Lithologic constituents
Major
Sedimentary > Clastic > Conglomerate
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic-tuff)
Sedimentary > Clastic > Sandstone
Minor
Metamorphic > Metasedimentary > Metaclastic > Quartzite
Comments The Jurassic quartz porphyry, Ali Molina, Mt Wrightson, Cobre Ridge, Black Rock volcanics, Planet Volcanics.
Stratigraphic units Ali Molina Formation, Topawa Group, Mount Wrightson Formation, Canelo Hills Volcanics, Cobre Ridge Tuff, Black Rock volcanics, Planet Volcanics
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.

Tosdal R.M., Haxel, G.B., and Wright, J.E., 1989, Jurassic geology of the Sonoran Desert region, southern Arizona, southeastern California, and northernmost Sonora: Construction of a continental-margin magmatic arc, in Jenney, J.P., and Rey

NGMDB product
Counties Cochise - La Paz - Mohave - Pima - Santa Cruz