Boulder Creek

Prospect, Inactive

Commodities and mineralogy

Main commodities Mo
Ore minerals molybdenite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale BD
Quadrangle map, 1:63,360-scale B-1
Latitude 64.37
Longitude -144.13
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Boulder Creek prospect is situated on a north facing ridge of Black Mountain that separates Summit Creek and Boulder Creek, a tributary of the Goodpaster River (Doyon Limited, 1998). The prospect is located at SW1/4 section 26, T. 6 S., R. 18 E., of the Fairbanks Meridian, approximately 54 miles east-northeast of Delta Junction, Alaska. A winter trail from the South Fork of the Goodpaster River provides access up Divide Creek to the immediate vicinity of the prospect. There are numerous surface workings at and surrounding the site. It is locality 7 of Cobb and Eberlein (1980), who summarized relevant references under the name 'Boulder Creek'.

Geologic setting

Geologic description

The area is characterized by rounded hills and flat-topped ridges (Thomas, 1970). The most prominent ridge is Black Mountain, which trends about 12 miles in a northerly direction and is underlain by Cretaceous granodiorite (Weber and others, 1978). A combination of augen gneiss, gneissic schist, and schist borders Black Mountain to the west. There is intense shearing and faulting in the contact between the metamorphic and intrusive rocks. Although most of the veining occurs in the shear zone, some is found in the intrusive rocks. This shear zone trends roughly N 15 E and dips 65 degrees NW. Veins are commonly 2 to 3 feet in width; some are as wide as 8 feet (Thomas, 1970). Molybdenite was observed sparingly in quartz veins in the granitic rock (Joesting, 1942). Doyon Limited (1998) documents the site as a Mo lode deposit.
The Goodpaster region was first explored for placer gold in 1915. In the early 1930s, gold-bearing quartz veins were discovered in the nearby upper Tibbs Creek area. From 1936 to 1941, the Blue Lead (BD003), Gray Lead (BD017), and Grizzly Bear (BD018) in the nearby Tibbs Creek area were mined for lode gold. The original base camp was on Summit Creek, a tributary of Boulder Creek (Joesting, 1938). Information regarding production or workings on Boulder Creek is not available.
Geologic map unit (-144.132322047856, 64.3696358474546)
Mineral deposit model Porphyry Mo (Cox and Singer, 1986; model 21b)?
Mineral deposit model number 21b?
Age of mineralization Veins cut Cretaceous intrusion.

Production and reserves

Workings or exploration The Goodpaster region was first explored for placer gold in 1915. In the early 1930s, gold-bearing quartz veins were discovered in the upper Tibbs Creek area. From 1936 to 1941, the Blue Lead (BD003), Gray Lead (BD017), and Grizzly Bear (BD018) in the nearby Tibbs Creek area were mined for lode gold. The original base camp was on Summit Creek (Joesting, 1938).
Indication of production None
Production notes Information regarding production on Boulder Creek is not available.

References

Reporters Cameron S. Rombach (ADDGS)
Last report date 4/26/1999