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National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • San Carlos Tuff
  • Modifications:
    • Geochronologic dating
  • AAPG geologic province:
    • Permian basin
Publication:

Henry, C.D., McDowell, F.W., Price, J.G., and Smyth, R.C., 1986, Compilation of Potassium-Argon ages of Tertiary igneous rocks, Trans-Pecos Texas: University of Texas-Austin, Bureau of Economic Geology Geological Circular, no. 86-2, 34 p.


Summary:

Pg. 22. San Carlos Tuff. Ash-flow tuff exposed in Big Bend area, Brewster County, and southern Presidio County, southwestern Texas, but was erupted from a caldera in the Sierra Rica area, Chihuahua, Mexico. Rhyolite samples from Chihuahua, Mexico, yielded K-Ar ages of 30.6 +/-0.7 Ma and 30.2 +/-0.7 Ma (alkali feldspar). Data from R.L. Chuchla, 1981 (Univ. Texas-Austin, MS thesis, 199 p.), J.L. Gregory, 1981 (Univ. Texas-Austin, MS thesis, 78 p.), and J.F. McKnight, 1970 (Univ. Texas-Austin Bur. Econ. Geol., Geol. Map Quad. No. 37); ages recalculated using decay constants of Steiger and Jager, 1977 (Earth Planet. Sci. Letters, v. 36, p. 359-362).
[Age considered Oligocene (from Geologic Names Committee, USGS, 1983 ed. geol. time scale, with additions from N.J. Snelling, 1985, The Geol. Soc. Mem., no. 10).]

Source: Publication.


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