- Usage in publication:
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- Sleeping Lion Formation
- Modifications:
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- Geochronologic dating
- AAPG geologic province:
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- Permian basin
Summary:
Pg. 12. Sleeping Lion Formation. Rhyolite samples from Mano Prieto Mountain and Fort Davis quadrangles, Jeff Davis County, southwestern Texas, yielded K-Ar ages of 37.4 +/-0.8 Ma and 36.8 +/-0.8 Ma (alkali feldspar), respectively. Data from D.F. Parker and F.W. McDowell, 1979 (GSA Bull., v. 90, p. 1100-1110), and M.A. Smith, 1975 (Univ. Texas-Austin, PhD dissert., 231 p.); ages recalculated using decay constants of Steiger and Jager, 1977 (Earth Planet. Sci. Letters, v. 36, p. 359-362).
[Age considered Eocene; Eocene-Oligocene boundary 36.6 (38-34) Ma (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.
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
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