GEOLEX

Summary of Citation: Datil Well

Publication:
Osburn, G.R. and Chapin, C.E., 1983, Nomenclature for Cenozoic
   rocks of northeast Mogollon-Datil volcanic field, New Mexico:
   New Mexico Bureau of Mines and Mineral Resources Stratigraphic
   Chart, no. 1

Usage in Publication:
Datil Well Tuff

Modifications:	Geologic Province:	Dominant Lithology:
Named	Basin-and-Range province	Tuff

Summary:
Named as one of the formations of Datil Group (rank raised). Known in Datil Mountains and northern Jornada del Muerto. Is thin but continuous in Datil Mountains. Is absent to east except for a few isolated remnants. Type section on northeast side White House Canyon 1.2 mi northwest of junction of US-60 and US-12 in town of Datil, NW1/4 SW1/4 sec 2, T2S, R10W, Catron Co, NM, Basin-and-Range province, measured and described. Is a 31.5 ft gray, purple to pink, densely welded, moderately crystal-rich ash-flow tuff above the andesite of White House Canyon of Spears Formation and beneath Chavez Canyon Member (new) of Spears. May also overlie Dog Springs Member (new) of Spears. Has an average age of 36.7 m.y. from Zr-F-T and K-Ar date on sanidine. Assigned to Oligocene. Source unknown.

Summary of Citation: Datil Well

Publication:
Marvin, R.F., Naeser, C.W., Bikerman, Michael, Mehnert, H.H.
   and Ratte, J.C., 1987, Isotopic ages of post-Paleocene igneous
   rocks within and bordering the Clifton 1 degrees x 2 degrees
   quadrangle, Arizona-New Mexico: New Mexico Bureau of Mines
   and Mineral Resources Bulletin, no. 118, 64 p.

Usage in Publication:
Datil Well Tuff

Modifications:	Geologic Province:	Dominant Lithology:
Isotopic dating	Basin-and-Range province

Summary:
Has yielded an age of 35.6 +/-1.3 m.y. (sanidine) and 37.7 +/-3.8 m.y. (zircon), Datil quad, and of 35.51 m.y. (40Ar/ 39Ar) Catron Co, NM, Basin-and-Range province.

Summary of Citation: Datil Well

Publication:
Ratte, J.C., McIntosh, W.C. and Houser, B.B., 1991, Geologic
   map of the Horse Mountain West quadrangle, Catron County,
   New Mexico: U.S. Geological Survey Geologic Quadrangle Map,
   GQ-1685, 1 sheet, scale 1:24,000, Supersedes U.S. Geological
   Survey Open-File Report OF-89-210.

Usage in Publication:
Datil Well Tuff*

Modifications:	Geologic Province:	Dominant Lithology:
Overview Isotopic dating Paleomagnetics	Basin-and-Range province

Summary:
Is formation in Datil Group. Is mapped in Horse Mountain West Quadrangle, Catron Co, NM, in eastern part of Basin-and-Range province. Is light-gray to light-pinkish-brown, densely welded ash-flow tuff; contains as much as 15 percent small phenocrysts, mainly sanidine (1-3 mm), minor to a trace of green clinopyroxene, plagioclase, biotite and opaque oxide, and rare quartz, brown hornblende or allanite, zircon, and apatite in a vitroclastic to granophyric matrix. Scattered lithic fragments are mostly brown andesitic rocks. Lack, or near lack of plagioclase may help to distinguish from overlying tuff of Farr Ranch. The two units may be separated from a few meters of volcaniclastic conglomerate, and only than can the two units be easily distinguished. Thickness is 0 to about 10m. Natural remanent magnetism determined as follows: mean inclination, 51.6; mean declination, 17.6; polarity, normal. Isotopic dating: 40 Ar/39 Ar age is 35.41 Ma, Oligocene.