Unnamed (in Taylor Mountains)

Occurrence, Inactive

Commodities and mineralogy

Main commodities B
Other commodities As; Cu; U
Ore minerals tourmaline
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale TA
Quadrangle map, 1:63,360-scale D-4
Latitude 60.9235
Longitude -157.4491
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is high in the Taylor Mountains about 1.2 miles west of peak 3581 (the highest peak in the Taylor Mountains) and about 0.1 mile north of elevation 3007. It is about 0.3 mile south of the center of section 28, T. 10 N., R,. 46 W. The location is accurate.

Geologic setting

Geologic description

Black tourmaline and quartz-tourmaline rock partly to completely replace porphyritic biotite granite of the Cretaceous Taylor Mountains pluton (Travis Hudson, unpublished field data, 2005) Coarse euhedral tourmaline aggregates are well developed along a northwest-trending vertical fracture or fault in the granite. The tourmaline-rich zone is at least several feet wide; float blocks of tourmaline and quartz-tourmaline rock are up to 4 or 5 feet thick. These blocks are scattered on the surface in a line for about one to two hundred feet. The host granite has large euhedral K-feldspar phenocrysts up to 8 to 10 centimeters long in a fine- to medium-grained equigranular groundmass. The Bureau of Land Management sampled this occurrence in 2004 (Ellefson and others, 2005). Two rock samples contained 100 and 300 parts per million (ppm) arsenic, 107 and 106 ppm copper, less than 5 and 15 ppm tin, less than 0.01 tantalum, and 2.96 and 15.3 ppm uranium. These samples contained only 10 and 70 ppm boron and are therefore not representative of the tourmaline-rich rocks at this locality. T. K. Bundtzen (personal communication, 2005 ) also sampled these tourmaline-rich rocks in 2005.
Geologic map unit (-157.45140201722, 60.9227981448301)
Mineral deposit model Tourmaline and quartz-tourmaline replacement in granite.
Age of mineralization Late Cretaceous, the age of the Taylor Mountains granite pluton.
Alteration of deposit Tourmaline and quartz replacement of porphyritic biotite granite.

Production and reserves

Workings or exploration Only limited surface sampling.
Indication of production None

References