Redline Prospect, Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi

Regional Level Types
Redline Prospect	Prospect
Fairbanks Mining District	Mining District
Fairbanks North Star Borough	Borough
Alaska	State
USA	Country

Location: The Redline prospect is a linear 2,000-foot anomaly of gold in soil on the ridge between Treasure Creek and Eagle Creek, about 2,000 feet north of Old Murphy Dome Road. It is in the SE1/4 sec. 17, T. 2 N., R. 1 W., Fairbanks Meridian, at an elevation of about 1400 feet.
Geology: The following geologic description is summarized from a report by Sam Dashevsky (1993) on work done by American Copper and Nickel Company on the Eagle Creek property in the early 1990's. Soil samples anomalous in gold,arsenic,and antimony define a linear trend 2,000 feet long. A 1,000-foot portion near the crest of a loess ridge contains 1,500 ppb gold. The linear gold anomaly coincides with the northern limit of an isolated block of schist. (This area was mapped by Newberry and others (1996) as Fairbanks Schist that consists of quartz-muscovite schist, quartzite, and chlorite-quartz schist). Rock fragments in float collected at various sample sites consisted of limonite-stained, altered, quartz-mica schist; chips of vein quartz were also noted. The schist fragments appear to be weakly argillized, are bleached, and contain quartz veins. A strongly mineralized zone is present on the upper contact of a 25-foot-thick felsic sill; the sill dips shallowly to the north, is fine- to medium-grained, and is equigranular to weakly porphyritic. This upper contact appears to be a fault, the Redline shear, that contains calcite veining and limonite staining. A hornfelsed, 3-foot-thick siliceous schist marks the base of the sill. The mineralized fault contact was sampled and contains 10 feet of rock that assays 0.09 ounce of gold per ton. One hole was drilled on the Redline shear and assays from the samples showed values similar to those found in the soil samples: 120-165 ppb gold, 588-1,148 ppm arsenic, 26-50 ppm antimony. The Redline shear was recognized in the drill hole as argillized, black, silicified phyllite. The sheared upper inrusive contact is marked by carbonate and limonite alteration.
Workings: In 1992, American Copper and Nickel Company conducted reconnaissance soil sampling and drilled one hole (Dashevsky, 1993).
Alteration: Schist fragments in soils appear to be weakly argillized, bleached, and veined with quartz. The Redline shear was recognized in the drill hole as argillized, black, silicified phyllite. The sheared upper contact of an intrusive body is marked by carbonate and limonite alteration (Dashevsky, 1993).

Commodities (Major) - Au
Development Status: None
Deposit Model: Gold-bearing shear zone at the contact of a felsic sill with schist.

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Link to USGS - Alaska:	FB075

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References