ANTELOPE WELLS

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 m²and 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.

[updated 1995] In the original study, geologic investigations were hampered by land closures at the source (Shackley 1988). 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 1989: 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.

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).

SAMPLE	Ti	Mn	Fe	Rb	Sr	Y	Zr	Nb	Ba	Pb	Th
1B1	1512	1184	25863	372	6	131	1275	101
5B3	1190	966	22438	345	6	133	1222	93
7B1	1367	1097	24538	381	8	137	1316	106
7B3	1410	1024	23250	361	7	136	1285	102
7B8	1381	1018	22291	357	5	133	1276	98
7B12	1405	1117	25989	392	9	143	1357	109
8H1	1282	945	22076	342	5	124	1215	96
8I1	1392	1102	24950	381	6	140	1310	100
AW1	1413	1091	24241	374	9	128	1329	105	45
AW2	1433	995	22222	341	8	123	1250	96	45
AW3	1405	1020	22298	340	7	126	1265	91	47
AW4	1284	919	20920	332	9	124	1235	95	45
AW5	1393	963	21459	342	6	124	1230	92	42
AW6	1325	864	20616	326	7	121	1203	96	48
AW7	1213	770	18126	303	6	119	1179	94	52
AW8	1583	1096	25810	377	8	132	1337	104	44
AW9	1553	1031	23912	355	8	127	1275	95	44
AW10	1309	937	21317	333	9	126	1247	98	45
AW11	1706	1010	21325	322	5	124	1228	94	47
AW12	1392	894	21632	336	8	127	1227	92	43
AW13	1244	854	20459	333	7	122	1222	92	47
AW14	1257	927	22337	350	9	123	1251	100	45
AW15	1500	919	21240	323	7	122	1204	92	46
AW16	1375	906	21151	329	6	123	1195	90	41
AW17	1254	925	22557	353	7	126	1247	96	46
AW18	1522	905	21242	340	10	130	1212	101	<1	44	43
AW20	1442	813	20768	339	8	132	1216	105	<1	40	46
AW21	1309	729	18040	300	8	125	1113	96	6	38	43
AW22	1439	823	19997	324	8	135	1181	105	19	39	40
AW23	1858	1152	26832	388	8	146	1312	114	<1	55	59
AW24	1306	673	17162	289	8	123	1088	92	1	36	44
AW25	1186	638	16512	292	9	120	1077	98	<1	37	43
AW26	1415	793	19914	328	10	126	1178	98	<1	41	40

During an obsidian provenance study for Sean Dolan (University of Oklahoma) on Casas Grandes (CG) outlier sites in northern Chihuahua, one artifact produced from this source was discovered from the Whalen/Minnis Site 315 (Shackley 2014). The one artifact produced from Sonora Unknown A from Site 315 is a source seen fairly frequently in the border region. With a relatively high concentration of Rb and very low Sr it is distinctive, but until now unlocated (Shackley 2005:85, Table A.17).

From Shackley (2005:85): SON Unknown A. "In 1997, 1999, and again in 2002, three archaeological projects in extreme southern Arizona on the border near Douglas, Arizona revealed the same set of elemental concentrations in some of the archaeological obsidian that does not match any known sources on either side of the border (Shackley 1997, 1999, 2002). This obsidian exhibits a relatively high Rb content over 300 ppm, and very low Sr (see Appendix). This source is provisionally called SON Unknown A (see Appendix for data)."

Additionally, one of the "unknown" source groups in the CG outlier sites called "Chihuahua Unknown B" comprises 10% of the artifacts in the assemblage, has been seen as far north as Fort Huachuca, Arizona and in Mimbres sites north of the border (Jeff Ferguson, personal communication, 2014; Craig Skinner, personal communication, 2014). It has an elemental composition similar to Antelope Wells, but with a much lower concentration of zirconium and slightly higher niobium. It is possible that this compositional group is the result of a co-genetic relationship with Antelope Wells, but is not always found in association with Antelope Wells obsidian, and redundant surveys by myself, Phil LeTourneau, and Office of Contract Archaeology staff, University of New Mexico, and my analyses of all these collections from both sides of the border at Antelope Wells has never detected this chemical group. Nevertheless, it is possible it is related to Antelope Wells and may be from a small dome complex nearby that has remained undetected. The Gray Ranch that owns much of the property in the area did not allow any research on their property historically. Both Chihuahua Unknown A and B given their presence in sites north of the border are likely sources near the border region. Time will tell.

In order to see if this unlocated source might be in the Antelope Wells area, I analyzed samples from my 1980s collection that had not been analyzed (samples A18-26 in table above), and while the Chihuahua Unknown B group was not evident, one marekanite had the "Sonora Unknown A" composition (see below). Findlow and Bolognese (1982) noted marekanites in the Peloncillo Mountains west of Antelope Wells on the Arizona/New Mexico line, but my surveys in the 1980s did not discover anything but vitrophyres. It is certainly possible that Sonora Unknown A is located in this area. I call this source provisionally "Animas Mountains".

Elemental concentrations for one marekanite recovered at Antelope Wells (AW19) and Sonora Unknown A samples from archaeological contexts north of the border (Shackley 1997, 1999, 2002). Ba, Pb, Th not analyzed in the archaeological studies.

Sample	Mn	Fe	Rb	Sr	Y	Zr	Nb	Ba	Pb	Th
AW19	631	10138	329	8	76	199	52	<1	23	26
Sonora Unk A	663	9744	292	3	56	173	41
Sonora Unk A	667	9599	325	4	59	189	43
Sonora Unk A	687	9796	316	1	61	190	45
Sonora Unk A	678	9461	313	2	57	187	44
Sonora Unk A	884	11341	365	0	68	208	53
Sonora Unk A	629	9225	288	0	61	161	32
Sonora Unk A	674	9569	326	3	69	211	42
Sonora Unk A	706	9718	307	3	55	186	40

Findlow, F.J. and M. Bolognese, 1982, A preliminary analysis of prehistoric obsidian use within the Mogollon area. In P.H. Beckett (Ed.) Mogollon Archaeology: Proceedings of the 1980 Mogollon Conference, pp. 297-316. Ramona, California: Acoma Press.

LeTourneau, P.D., 1994, Geologic investigations of the Antelope Wells obsidian source, Southern Animas Mountains, New Mexico. Paper presented at the 59th annual meeting of the Society for American Archaeology, Anaheim.

Shackley, M.S., 1988, Sources of Archaeological Obsidian in the Southwest: An Archaeological, Petrological, and Geochemical Study. American Antiquity 53:752-772.

Shackley, M.S., 1989, Early Hunter-Gatherer Procurement Ranges in the Southwest: Evidence from Obsidian Geochemistry and Lithic Technology. Ph.D. dissertation, Department of Anthropology, Arizona State University.

Shackley, M.S., 1997, An energy-dispersive x-ray fluorescence (EDXRF) analysis of obsidian artifacts from AZ FF:12:48 (ASM) southeastern Arizona. Report prepared for Pat Gilman, Department of Anthropology, University of Oklahoma, Norman.

Shackley, M.S., 1999, An energy-dispersive x-ray fluorescence (EDXRF) analysis of obsidian artifacts from the Boss Ranch Site (AZ FF:7:10 ASM), Cochise County, southeastern Arizona. Report prepared for John Douglas, University of Montana.

Shackley, M.S., 2002, Source provenance of archaeological obsidian from Mimbres Mogollon sites in the Cedar Mountains, southwest New Mexico. Report prepared for the Bureau of Land Management, Albuquerque, New Mexico.

Shackley, M.S., 2005, Obsidian: Geology and Archaeology in the North American Southwest. Tucson: University of Arizona Press.

Shackley, M.S., 2014, Source provenance of obsidian artifacts from the Casas Grandes Outlier Sites 204, 242, and 315, Northern Chihuahua. Report prepared for Sean Dolan, Department of Anthropology, University of Oklahoma, Norman.

Zeller, R.A., 1962, Reconnaissance geologic map of the Southern Animas Mountains. New Mexico Institute of Mining and Technology, Socorro.