Infiernito caldera volcanic rocks including Capote Mountain Tuff, Tsh2 of Shely Group, Buckshot Ignimbrite, and Tm1 of Morita Ranch Formation (TXEOin;0)

State	Texas
Name	Infiernito caldera volcanic rocks including Capote Mountain Tuff, Tsh2 of Shely Group, Buckshot Ignimbrite, and Tm1 of Morita Ranch Formation
Geologic age	Phanerozoic \| Cenozoic \| Tertiary \| Eocene-Late
Original map label	Ein
Comments	Present in Presidio Co.,TX. From older to younger--precollapse rhyolitic to trachytic lavas, Infiernito Tuff--a rhyolitic, thick intracaldera and thin outflow ash-flow tuff and interbedded caldera-collapse breccia, post-collapse lavas--coarsely porphyritic quartz trachyte lava and caldera-fill sediments (interbedded tuffaceous sediments, conglomerate, and debris-flow deposits), rhyolite dome, and the major intrusion of the infiernito caldera, the Ojo Bonito quartz monzonite. The possible maximum thickness of Infiernito Ignimbrite is estimated to be 5,900 ft. (Henry and others, 1992). Capote Mountain Tuff is one of seven formations of Vieja Group. The Capote Mt Tuff (on Marfa Sheet, 1979) contains fine-grained, vitric, tuffaceous sandst. and siltst., a few interbeds of conglomerate. In the north it is v. lt. gray and few pale red beds; in south, lower 2/3 is pale red, upper 1/3 v. lt. gray. Thickness 600-1,200 ft. Contains vertebrate mammalian fossils believed by some in 1979 to be Oligocene in age. Tsh2 of Shely Group--trachyte, to 400 ft thick, exposed at north end of Chinati Mountains.
Primary rock type	trachyte
Secondary rock type	rhyolite
Other rock types	sandstone; trachyandesite; latite; trachybasalt; basalt; ash-flow tuff; mudstone; conglomerate
Lithologic constituents	Major Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic, ash-flow) Igneous > Volcanic > Felsic-volcanic > Trachyte (Flow) Igneous > Volcanic > Felsic-volcanic > Rhyolite (Flow) Minor Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow) Incidental Sedimentary > Clastic > Mixed-clastic > Conglomerate-sandstone (Bed) Igneous > Hypabyssal > Felsic-hypabyssal (Dike or sill) Sedimentary > Clastic > Conglomerate (Bed) Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-rhyolite (Laccolith) Igneous > Hypabyssal > Felsic-hypabyssal > Hypabyssal-quartz-trachyte (Dike or sill)
Map references	Bureau of Economic Geology, 1992, Geologic Map of Texas: University of Texas at Austin, Virgil E. Barnes, project supervisor, Hartmann, B.M. and Scranton, D.F., cartography, scale 1:500,000
Unit references	Bureau of Economic Geology, 1979, Marfa Sheet, Geologic Atlas of Texas: Bureau of Economic Geology and The University of Texas at Austin, scale 1:250,000. Amsbury, D.L., 1958, Geology of the Pinto Canyon area, Presidio County, Texas: University of Texas at Austin, Bureau of Economic Geology Geologic Quadangle Map 22, scale 1:63,360. Henry, C.D., Price, J.C., Duex, T.W., and James, E.W., 1992, Geology of the Infiernito caldera and magmatic evolution of the Chinati Mountains, Trans-Pecos Texas: The University of Texas at Austin, Bureau of Economic Geology, Report of Investigations no.
Geographic coverage	Presidio