Location: The Black Mountain area is a four square mile upland between Tozer Creek and the California River, in the northern Teller B-4 quadrangle and adjacent parts of the Teller C-4 quadrangle. Large parts of this area are thermally metamorphosed and tactite is widespread. However, the prospect area described here is at about 1700 feet elevation on the southwest ridgecrest between headwaters to Constance Creek and an unnamed east tributary to Tozer Creek. This is locality 13 of Cobb and Sainsbury (1972). Cobb (1975) summarized relevant references under the name 'Black Mtn.'.
Geology: The upland including Black Mountain is an area of hornfels, calc-silicate hornfels, and tactite intruded by a locally exposed biotite granite. The metasedimentary rocks, fine-grained metapelitic and metacarbonate rocks, are of unknown but probable Paleozoic age. The Late Cretaceous (79.1 +/- 2.9 my, Hudson and Arth, 1983, p. 769) biotiote granite, medium-grained and equigranular, is exposed in a small area on the southern flanks of the upland and is interpreted to be part of an early precurser granite phase rather than an mineralyzing granite phase (Hudson and Arth, 1983, p. 784; Hudson and Reed, 1997, figure 3). The wide distribution of thermally metamorposed rocks and the results of gravity and aeromagnetic surveys (McDermott, 1983a) indicate that most of the Black Mountain area is underlain by granite at depth. The area is transected by many normal faults and related fractures. Sainsbury and Hamilton (1967, p. B23) noted the presence of quartz-topaz greisen with cassiterite, pyrite, pyrrhotite, sphalerite, and galena in the northeast part of the exposed granite body but most of the mineralization and alteration in the area is associated with calc-silicate rocks. Calc-silicate rocks contain garnet, idocrase, tourmaline, wollastonite, and epidote. Cross-cutting veins and alteration along normal faults and fractures include quartz, tourmaline, fluorite, and sulfide minerals (pyrite, sphalerite, arsenopyrite, and probably others). Cassiterite and wolframite have not been conclusively identified in the calc-silicate rocks. Only reconnaissance geochemistry for a few rock samples is available (Sainsbury and Hamilton, 1967, p. B24; Hudson, 1984, p. 20). Tin is weakly anomalous in most tactite samples but one garnet-epidote-idocrase rock contained 1,800 ppm tin. Weak base metal, silver, and gold (60 and 100 ppb) and strong arsenic (400 ppm), fluorine (over 20,000 ppm), and boron (2,230 ppm) anomalies are present in some rocks.
Workings: Some reconnaissance rock geochemistry and traverse geology, regional gravity and aeromagnetic surveys, and some onsite magnetic character and susceptability determinations have been completed (Hudson, 1984; McDermott, 1983a; 1983b; Reed and others, 1989).
Age: Late Cretaceous; the Black Mountain biotite granite, interpreted to be linked to alteration and mineralization in this area, has been determined to be 79.1 +/- 2.9 my old by the K/Ar method (Hudson and Arth, 1983, p. 769).
Alteration: Calc-silicate hornfels and tactite development is common; late quartz-fluorite +/- tourmaline veining and alteration is present along faults and fractures

Commodities (Major) - Sn
Development Status: None
Deposit Model: Tin skarn (Cox and Singer, 1986; model 14b).

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Standard Detailed Gallery Strunz Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

ⓘ Tin

Mineral List

9 valid minerals.