Dahl Creek

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale BN
Quadrangle map, 1:63,360-scale B-6
Latitude 65.365
Longitude -164.714
Nearby scientific data Find additional scientific data near this location
Location and accuracy This is approximatly located near the mouth of Dahl Creek (probably within a half mile). Dahl Creek is a northeast -flowing tributary to Quartz Creek. Quartz Creek crosses the Nome-Taylor road at about mile 78.5, Brakes Bottom. The mouth of Dahl Creek on Quartz Creek is about 8,000 feet upstream from the road crossing. This is the location used for altered bedrock reported by Sainsbury and others (1969). It is locality 4 of Cobb (1972; MF 417; 1975; OFR 75-429).

Geologic setting

Geologic description

Sainsbury and others (1969) describe a highly sericitized, clay-rich altered zone containing ground-up and angular vein quartz but do not report any geochemical data for this area. Altered schist is apparently common where bedrock is exposed in the Dahl Creek drainage. Early reports described the alluvial pay in the main Dahl Creek drainage to be on a false bedrock of clay below which there was a quartz gravel (Collier and others, 1908). A test shaft, which did not reach bedrock, indicated this deep gravel to be at least 187 feet thick. However, Sainsbury and others (1969) concluded that the false bedrock described by early reports was instead altered bedrock. Bedrock is locally exposed in the area, primarily on the crest of nearby uplands, but Sainsbury and others (1969) note some bedrock in the drainage 7,000 feet above the mouth. All known bedrock in the area is part of a lower Paleozoic metasedimentary assemblage (Sainsbury and others, 1969; Till and others, 1986).
Geologic map unit (-164.716665488795, 65.3642641937435)
Mineral deposit model Gold-bearing quartz veins and schist.
Age of mineralization Possibly mid-Cretaceous; if gold-bearing lode structures are present here they may be similar in age to some lode gold deposits of southern Seward Peninsula. The southern Seward Peninsula lode gold deposits formed as a result of mid-Cretaceous metamorphism (Apodoca, 1994; Ford, 1993, Ford and Snee, 1996; Goldfarb and others, 1997) that accompanied regional extension (Miller and Hudson, 1991) and crustal melting (Hudson, 1994). This higher temperature metamorphism was superimposed on high pressure/low temperature metamorphic rocks of the region.
Alteration of deposit Schist in this area is apparently highly sericitized and clay-rich (Sainsbury and others, 1969). The presence of broken quartz veins in the alteration zones may indicate that the alteration is developed along fault structures.

Production and reserves

Workings or exploration Local bedrock exposures along Dahl Creek are the result of open-cut placer mining operations, particularly dozer and sluice operations since WWII.
Indication of production None

References

MRDS Number 10307262

References

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.
Reporters Travis L. Hudson (Applied Geology)
Last report date 3/15/1999