New Mexico Mineral Symposium — Abstracts

The Lone Pine mine area, in the Wilcox district, Catron County, New Mexico, has been the site of modest mineral production. The district has produced 5 tons of tellurium and less than 100 ounces of gold and silver (1.23 oz. Au and 19.0 oz Ag officially reported). The Wilcox district is also credited with the production of 10,603 tons of fluorite (McAnulty, 1978). Despite the production of metal and fluorite, the area is probably best known for its tellurium minerals. However, very little systematic work on the mineralogy has been attempted prior to this study.

The ore deposits are hosted by Tertiary volcanic and volcaniclastic rocks, mainly in the Mogollon and Mineral Creek andesite units of Ratte et al. (1979). Mineralization tends to be confined to north- and northwest-trending fault zones that were in turn intruded by flow-banded rhyolite dikes. The rhyolites are bleached, silicified, and iron stained, to various degrees. The adjacent volcanic rocks are argillized, locally silicified, and strongly iron stained in places. Previous workers in the district attribute mineralization to late-stage volcanism and buried plutonism related to the develop¬ment of the ring complex of the Bursum caldera (Oligocene).

Primary mineralization occurs as fracture fillings in veinlets in the silicified flow-banded rhyolite at most prospects. Disseminated mineralization is also present. At the Lone Pine mine, primary mineralization occurs in larger pods in a large zone of silicified flow-banded rhyolite and silicified andesite. Primary mineralization consists of pyrite, fluorite, tellurium, and molybdenum. A precious-metal telluride, krennerite(?), was identified for the first time in the district during this study. A vertical mineralogical zonation is apparent with pyrite stratigraphically lowest grading into pyrite-tellurium assemblage followed by a fluorite-rich zone at the highest elevations. Tellurium mineralization is strongest at the pyrite—fluorite transition zone. Ballmer (1932) reported bismuthinite in the ores, but the mineral was not observed in this study.

As a result of the unique chemistry of tellurium-oxygen molecules and their behavior in the weathering environment, tellurites and tellurates are the most abundant tellurium species in the district. Tellurite and paratellurite (both TeO₂) were observed in the district for the first time, usually growing on native tellurium. In addition, the weathering of pyrite and native tellurium gives rise to a host of iron tellurate minerals including emmonsite (Fe₂Te₃O₉ • 2H₂O), mackayite (FeTe₂O₅(OH)), sonoraite (FeTeO₃(OH) •H₂O), blakeite (Fe₂(TeO₃)₃), poughite (Fe₂(TeO₃)₂(SO₄) • 3H₂O), and perhaps other, more rare, iron tellurates (rodalquilarite and curticite). The district is the type locality for a copper tellurate, rajite (CuTe₂O₅). A second copper tellurate, teineite (CuTeO₃ • 2H₂O), was also noted during this study (rajite was reported as a pseudomorph of teineite by Williams, 1972). The presence of copper tellurates in the absence of a primary copper phase is somewhat enigmatic. However, the report of bismuthinite in the district also suggests the potential for a number of bismuth tellurates (smirnite, montanite, and chekhovichite) to be found in the area. There is potential for additional telluride minerals to exist in the district also, including bismuth and other precious metal varieties. Finally, the unique bonding characteristics of tellurates hold promise for the discovery of new tellurate mineral species in the area.
 

References:

1. Ballmer, Gerald J., 1932, Native tellurium from northwest of Silver City, New Mexico: American Mineralo??gist, v. 17, pp. 491-492.
2. Crawford, R. D.,1937, Tellurium minerals of New Mexico: American Mineralogist, v. 22, pp. 1065-1069. McAnulty, W. N., 1978, Fluorspar in New Mexico: New Mexico Bureau of Mines and Mineral Resources, Memoir 34, 64 pp.
3. Ratte, J. C., Gaskill, D. L., Eaton, G. P., Peterson, D. L, Stotelmeyer, R. B., and Meeves, H. C., 1979, Mineral resources of the Gila Primitive Area and Gila Wilderness, New Mexico: U.S. Geological Survey, Bulletin 1451, 229 pp.
4. Williams, S. A., 1979, Rajite, naturally occurring cupric pyrotellurate, a new mineral: Mineralogical Magazine, v. 43, pp. 91-92.