Green Spike

Prospect, Inactive

Alternative names


Commodities and mineralogy

Main commodities Ag; Cu; Mo
Other commodities Sn; Zn
Ore minerals cassiterite; chalcopyrite; molybdenite; pyrite; sphalerite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale HE
Quadrangle map, 1:63,360-scale A-4
Latitude 63.1
Longitude -148.885
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Green Spike prospect is at an elevation of about 4,500 feet, at the southwest head of East Fork Chulitna River. The map site is about 2.75 miles east southeast of VABM 5854 (Alf), in the northwest corner of sec. 15, T. 21 S., R. 7 W., of the Fairbanks Meridian. The accuracy of this location is within 1,000 feet. This is locality D4 of Balen (1990: OFR 34-90).

Geologic setting

Geologic description

The Green Spike prospect is at the contact between a Tertiary granitic pluton and a slightly younger (Oligocene) complex of hypabyssal felsic dikes and remnants of a rhyolite flow. Both the granite and younger complex cut Jurassic to Cretaceous metamorphosed graywacke. The deposit is in the rhyolite, and consists of quartz veins containing cassiterite, chalcopyrite, molybdenite, pyrite, and sphalerite. Samples assay 0.48% copper, 819 ppm zinc, 0.4 ounce of silver per ton, 13 ppm tin, and 25 ppm molybdenum (Balen and others, 1991). The high molybdenum-tin-silver values, the evolved intrusive host-rocks, and their younger age distinguish this deposit from the copper-gold-rich deposits on the other side of the Chulitna Valley (for example, HE043).
Geologic map unit (-148.887264314803, 63.0995321003001)
Mineral deposit model Porphyry Sn (Cox and Singer, 1986; 20a)
Mineral deposit model number 20a
Age of mineralization Volcanic rocks hosting the deposit are considered Oligocene (Wilson and others, 1998).

Production and reserves

Workings or exploration Surface sampling only.
Indication of production None