|Name||Oligocene intrusive rocks|
Igneous > Volcanic > Felsic-volcanic (Pyroclastic-tuff)
Igneous > Volcanic > Felsic-volcanic > Trachyte
Igneous > Volcanic > Mafic-volcanic > Basalt (Stock or pipe)
Igneous > Plutonic > Granitic > Granite (Stock or pipe)
|Comments||stocks, laccoliths, sills, and dikes. Major rock types--basalt, hawaiite, mugearite, trachyte, quartz trachyte, rhyolite, phonolite, latite, trachyandesite, and their coarser grained equivalents. At Marble Canyon intrusive stock in Diablo Mtns, Culberson Co, 30 mi north of Van Horn, TX, (Price and Henry, 1986, p. 17), rocks are alkali gabbro, nepheline syenite dikes, quartz syenite at core of stock, also hybrid rock, numerous contact metamorphism and hydrothermal minerals reported. K-Ar ages about 33, 35, 36, 37, and 39.5 Ma (p. 22). Quitman-Sierra Blanca complex are caldera ring-dike intrusives and stocks: quartz monzonite, rhyolite, granite (laccolith). K-Ar age 33.9+-0.8 Ma (Shannon and Goodell, 1986).|
Price, J.G., and Henry, C.D., 1986, Geology of Marble Canyon in Price, J.G., Henry, C.D., Parker, D.F., and Barker, D.S., eds., Igneous geology of Trans-Pecos Texas, field trip guide and research articles: The University of Texas at Austin, Bureau of Economic Geology, Guidebook 23, p. 17-26.
Shannon, W.M. and Goodell, P.C., 1986, Lithochemistry of intrusive rocks of the Quitman-Sierra Balnce igneous complex, Hudspeth County, Texas in Price, J.G., Henry, C.D., Parker, D.F., and Barker, D.S., eds., Igneous geology of Trans-Pecos Texas, field trip guide and research articles: The University of Texas at Austin, Bureau of Economic Geology, Guidebook 23, p. 225-236.
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.
|Counties||Brewster - Culberson - El Paso - Hudspeth - Jeff Davis - Presidio|