ANTELOPE WELLS

(EL BERRENDO)

SOUTHWESTERN NEW MEXICO

AND

NORTHWESTERN CHIHUAHUA

Collected from: Sections 9,10,11,12,13,14,23,24 (and area adjacent sections 23 and 24 in Chihuahua) R17W, T34S USGS Whitewater Mountains 7.5' Quad, south central Hidalgo County, New Mexico and adjacent Chihuahua where the source is colloquially known as El Berrendo.

Findlow and Bolognese describe Antelope Wells as "a point source" with apparently little secondary dispersion (1982:57). They state that the nodules are located in the Clanton Draw drainage in the Peloncillo Mountains (Findlow and Bolognese 1982:57). Two days of survey in the Clanton Draw locality failed to yield any vitreous obsidian. The only glass recovered was devitrified vitrophyre. Unfortunately, the primary source at Deer Creek could not be investigated since New Mexico Hwy 79 is permanently closed by Gray Ranch Properties. However, nodules were recovered as secondary deposits in the lower Deer Creek drainage and in alluvium east and south of the Animas Mountains. Zeller (1962) records "nodular obsidian inclusions" in the OK-Bar Conglomerate along the upper Deer Creek drainage in the southern Animas Mountains. This is located in, at least, Sections 11,12,13,14 R19W, T33S of USGS San Luis Pass 7.5' Quad.

While Findlow and Bolgnese may be correct in that the Deer Creek primary source is "a point source" (1982:57), the nodules are distributed at least 15 to 20 km east and south into Chihuahua. If nodules occur in the nearby Peloncillo Mountains as stated by Findlow and Bolognese, the source stretches considerably farther west, perhaps into Arizona. The density of the nodules ranges up to 5 per 5 m² and is likely much higher upstream. Nodule diameters in the alluvium reached 6 cm and Findlow and Bolognese report sizes up to 15 cm (1982:57). The material is an excellent medium for tool production, certainly equal to the other mid-Tertiary marekenites of Arizona. The cortex on the alluvial specimens is smooth black through velvet black. The color of the aphyric glass covers a similar spectrum as Sauceda; in fact they are nearly identical megascopically. Translucent brownish-green is common, but dark gray, green/brown banded and opaque black colors also occur.

Nodules were reduced everywhere in the alluvial deposits, but the low density (<1 per 10 m²) reflects the low geological occurrence. References include the Findlow and Bolognese material above plus Zeller (1962).

[updated 1995] In the original study, geologic investigations were hampered by land closures at the source (Shackley 1988a; 1990). An important observation was that contrary to the Findlow and Bolognese (1982) study, no artifact quality marekenites could be located in the Peloncillo Mountains, and there was considerable secondary dispersion of the nodules in the area (Shackley 1990: 201-202). An important new study of this source by LeTourneau (1994) amplifies this observation and provides useful insight. LeTourneau's intensive study of the geology and petrology with access to the OK Bar Conglomerate and Deer Creek, indicate that this is a rather typical Tertiary peralkaline glass source with a probable rhyolite formation origin and attendant secondary deposition (LeTourneau 1994). LeTourneau did find marekanites in situ in tuff and conglomerates, and volcaniclastics of Culberson Ranch (Tvcr; 1994:4). No nodules were located in perlitic lava. Nodule sizes, however, located by LeTourneau are about the same size as those reported in my original survey (up to 6 cm), but the extent of the deposit is much greater. LeTourneau (1994) notes a number of geological studies in the area including Erb (1979), as well as Alper (1961), and Zeller (1965).

Elemental concentrations for Antelope Wells source standards. Those samples with "A" prefixes from Shackley, all others collected by LeTourneau. All measurements in parts per million (ppm).

This page maintained by Steve Shackley (shackley@berkeley.edu).
Copyright © 2001 M. Steven Shackley. All rights reserved.
Revised: 12 March 2004

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