Unnamed (lode near Fred Creek)

Prospect, Probably inactive

Commodities and mineralogy

Main commodities Au
Other commodities As
Ore minerals gold; hematite

Geographic location

Quadrangle map, 1:250,000-scale NM
Quadrangle map, 1:63,360-scale D-1
Latitude 64.7825
Longitude -165.4355
Nearby scientific data Find additional scientific data near this location
Location and accuracy Mineralized schist occurs about 600 feet southwest of upper Fred Creek (Gulch) in the approximate center of the SW1/4NE1/4 section 19, T. 8 S., R. 33 W., Kateel River Meridian. The location is accurate to within 250 feet of the coordinates.

Geologic setting

Geologic description

The basal contact zone of massive marble with schist is mineralized at this locality. The mineralized rock is hematized schist that is anomalous in gold and arsenic; arsenic is inferred to be present in a secondary mineral oxidized from arsenopyrite. This mineralization was found as a result of a soil geochemistry survey, but similar mineralization could exist widely at this stratigraphic and structural contact. The deposit could be the source of most of the gold in the Fred Creek placer (NM064). About 2,400 feet southwest of this prospect are numerous boulders of angular vein quartz float on muskeg soil. The quartz is about on trend with the Penny River fault (branch or main splay) that goes through the California prospect (NM062; C.C. Hawley, written communication, 1995).
The metasedimentary schist and overlying massive marble unit (Bundtzen and others, 1994) are part of the Nome Group derived from Proterozoic to early Paleozoic protoliths (Till and Dumoulin, 1994). The Nome Group underwent regional blueschist facies metamorphism in the Late Jurassic or Early Cretaceous (Sainsbury, Coleman, and Kachadoorian, 1970; Forbes and others, 1984; Thurston, 1985; Armstrong and others, 1986; Hannula and McWilliams, 1995). The blueschist facies rocks were recrystallized to greenschist facies or higher metamorphic grades in conjunction with regional extension, crustal melting, and magmatism in the mid-Cretaceous (Hudson and Arth, 1983; Miller and Hudson, 1991; Miller and others, 1992; Dumitru and others, 1995; Hannula and others, 1995; Hudson, 1994; Amato and others, 1994; Amato and Wright, 1997, 1998). Lode gold mineralization on Seward Peninsula is mostly related to the higher temperature metamorphism in the mid-Cretaceous (Apodoca, 1994; Ford, 1993 [thesis]; Ford and Snee, 1996; Goldfarb and others, 1997).
Geologic map unit (-165.43812247581, 64.7817384040806)
Mineral deposit model Possible low sulfide, Au-quartz vein (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a?
Age of mineralization Mid-Cretaceous?; structures controlling deposits postdate regional metamorphism - mineralization could be similar in age to other lode gold deposits of Seward Peninsula.
Alteration of deposit Oxidation; possible development of secondary layered silicates; sulfidation of contact zone.

Production and reserves

Workings or exploration The area was explored by Kennecott Exploration Company in 1994. Kennecott extended an earlier soil geochemistry survey that was confined to the immediate area of the California mine (NM062). The extended survey found soils anomalous in gold and arsenic near the basal contact of massive marble in Fred Creek. Quartz boulders were found and mapped along the survey lines. Reconnaissance along the apparent northeast-trend of mineralization led to discovery of old hand placer workings in Boulder Creek, the next (northeast) tributary to Stewart (Ben Porterfield, oral communication, 1995). A trench cut by Kennecott in 1996 found a 200-foot-wide fault zone in the Fred Creek lode prospect area. The area has been further explored by Consolidated Aston.
Indication of production None

Additional comments

Basal contact zone of massive marble is a favorable horizon in the Fred Creek area; also a major fault, probably related to the Penny River fault traverses the area.

References

MRDS Number 10307934

References

Apodoca, L.E., 1994, Genesis of lode gold deposits of the Rock Creek area, Nome mining district, Seward Peninsula, Alaska: Boulder, Colorado, University of Colorado, Ph.D. dissertation, 208 p.
Armstrong, R.L., Harakal, J.E., Forbes, R.B., Evans, B.W., and Thurston, S.P., 1986, Rb-Sr and K-Ar study of metamorphic rocks of the Seward Peninsula and southern Brooks Range, Alaska, in Evans, B.W., and Brown, E.H., eds., Blueschists and eclogites: Geological Society of America Memoir 164, p. 184-203.
Ford, R.C., 1993, The geology, geochemistry, and age for lode sources of placer gold deposits in the Seward Peninsula: Technical Presentation, Denver Region Exploration Geologists' Society, November 6, 1993, Denver, Colo., unpaginated.
Ford, R.C., and Snee, L.W., 1996, 40Ar/39Ar thermochronology of white mica from the Nome district, Alaska--The first ages of lode sources to placer gold deposits in the Seward Peninsula: Economic Geology, v. 91, p. 213-220.
Goldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W, 1997, Gold deposits in metamorphic rocks in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 151-190.
Hannula, K.A., and McWilliams, M.O., 1995, Reconsideration of the age of blueschist facies metamorphism on the Seward Peninusla, Alaska, based on phengite 40Ar/39Ar results: Journal of Metamorphic Geology, v. 13, p. 125-139.
Hannula, K.A., Miller, E.L., Dumitru, T.A., Lee, Jeffrey, and Rubin, C.M., 1995, Structural and metamorphic relations in the southwest Seward Peninsula, Alaska; Crustal extension and the unroofing of blueschists: Geological Society of America Bulletin, v. 107, p. 536-553.
Hudson, T.L., 1994, Crustal melting events in Alaska, in Plafker, G., and Berg, H. C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, Vol. G-1, p. 657-670.
Hudson, T.L., and Arth, J. G., 1983, Tin granites of Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 94, p. 768-790.
Miller, E.L., Calvert, A.T., and Little, T.A., 1992, Strain-collapsed metamorphic isograds in a sillimanite gneiss dome, Seward Peninsula, Alaska: Geology, v. 20, p. 487-490.
Thurston, S.P., 1985, Structure, petrology, and metamorphic history of the Nome Group blueschist terrane, Salmon Lake area, Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 96, p. 600-617.
Till, A.B., and Dumoulin, J.A, 1994, Geology of Seward Peninsula and St. Lawrence Island, in Plafker, G., and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, v. G-1, p. 141-152.
Reporters C.C. Hawley and Travis L. Hudson
Last report date 10/22/1999