Unnamed (Spooky Valley)

Occurrences, Inactive

Commodities and mineralogy

Main commodities Ag; Pb; Zn
Other commodities Bi; La; Mo; Sn; U; W
Ore minerals hematite
Gangue minerals chlorite; epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale TN
Quadrangle map, 1:63,360-scale C-3
Latitude 65.72847
Longitude -151.19274
Nearby scientific data Find additional scientific data near this location
Location and accuracy This record represents occurrences of anomalous rock samples in a five-square-mile area of the central Ray Mountains in Spooky Valley and along ridges to the north and east. For this record, the site is Alaska Division of Geological and Geophysical Surveys (ADGGS) sample station 92MW451 (Solie and others, 1993), at the northwest corner of section 6, T. 10 N., R. 17 W., of the Fairbanks Meridian. The location is accurate within 1000 feet.

Geologic setting

Geologic description

The country rocks in the area of this site are granitic rocks of the Cretaceous, Ray Mountains batholith, which trends east-west across the northeast-trending Ruby-Hodzana upland (Dover, 1994). The batholith constitutes the core of the Ray Mountains and includes at least four phases: K-feldspar-rich, porphyritic granite; biotite granite; two-mica granite; and granodiorite. Several K-Ar, Rb-Sr whole rock, and U-Pb age dates on various phases of the batholith range from 104 to 111.6 Ma (Dover, 1994). The isotope chemistry of plutonic rocks from the Ray Mountains indicates that they are S-type plutons derived from or contaminated by continental crust. A brittle-fracture fabric and high-angle fault pattern are superimposed on more ductile older fabrics (Dover, 1994). Brittle structures are expressed mainly as northeast-trending topographic lineaments having generally small, down-to-the-northwest, dip-slip offsets.
In 1992, the Alaska Division of Geological and Geophysical Surveys (ADGGS) investigated the Spooky Valley area as part of a mineral resource evaluation of State-selected lands (Solie and others, 1993). The Spooky Valley area is in the center of the eastern lobe of the Ray Mountains batholith (Chapman and others, 1982). The rocks in the area are textural variants of granite and biotite granite. The granite commonly is hematite stained (altered) and locally brecciated (Solie and others, 1993). ADGGS collected 23 rock samples for geochemical analysis. Twelve of the samples (at stations 92Ha259, 92RE2034, 92MW450, 92MW451, 92MW452, 92MW453, and 92MW454) contained the following maximum values for one or more of the following commodities: 43 parts per million (ppm) uranium, 110 ppm tungsten, 73 ppm bismuth, 1,771 ppm lead, 110 ppm tin, 5,308 ppm zinc, 15.9 ppm silver, 13 ppm molybdenum, and 140 ppm lanthanum.
Geologic map unit (-151.195319502017, 65.727978150532)
Mineral deposit model Sn-polymetallic veins, polymetallic veins (Cox and Singer, 1986; models 20b and 22c).
Mineral deposit model number 20b, 22c
Age of mineralization Cretaceous, the age of the granitic hostrock.

Production and reserves

Workings or exploration In 1992, the Alaska Division of Geological and Geophysical Surveys (ADGGS) investigated the Spooky Valley area as part of a mineral resource evaluation of State-selected lands (Solie and others, 1993). The Spooky Valley area is in the center of the eastern lobe of the Ray Mountains batholith (Chapman and others, 1982). The rocks in the area are textural variants of granite and biotite granite. The granite commonly is hematite stained (altered) and locally brecciated (Solie and others, 1993). ADGGS collected 23 rock samples for geochemical analysis. Twelve of the samples (at stations 92Ha259, 92RE2034, 92MW450, 92MW451, 92MW452, 92MW453, and 92MW454) contained the following maximum values for one or more of the following commodities: 43 parts per million (ppm) uranium, 110 ppm tungsten, 73 ppm bismuth, 1,771 ppm lead, 110 ppm tin, 5,308 ppm zinc, 15.9 ppm silver, 13 ppm molybdenum, and 140 ppm lanthanum.
Indication of production None

References