Unnamed Prospect (ARDF - FB074; in upper Treasure Creek), Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi

Regional Level Types
Unnamed Prospect (ARDF - FB074; in upper Treasure Creek)	- not defined -
Fairbanks Mining District	Mining District
Fairbanks North Star Borough	Borough
Alaska	State
USA	Country

Location: This prospect is a 1,700-foot by 1,000-foot area on the western side of upper Treasure Creek that is defined by anomalous gold, antimony, arsenic, lead, and silver in soils. It trends southwest toward the saddle along Any Creek Trail (winter) that is 2,500 feet north of Old Murphy Dome Road in the SE1/4 sec. 18, T. 2 N., R. 1 W ., Fairbanks Meridian.
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. In the 1970's, an arsenic soil anomaly was identified in the area, and two samples were identified that contained more than 100 ppb gold. The soil anomaly is approximately 1,700 feet by 1,000 feet in area and contains anomalous levels of gold, antimony, arsenic, lead, and silver with erratic boron, copper and zinc values. The soil anomaly is underlain by quartz-mica schists, minor quartzite, and minor graphitic schist. (This area was mapped by Newberry and others (1996) as Fairbanks Schist that consists of quartz-muscovite schist, quartzite, and chlorite-quartz schist). Silicification and quartz veining were noted in approximately half the soil pits. The trace of the anomaly follows the southern contact zone of a feldspar porphyry body. The soil anomaly diminishes over an intrusive. The igneous float in the area is altered to clay and locally silicifiied. A north-dipping fault has been inferred from airphotos and soil geochemistry. An east-northeast trending linear was traced from airphotos; the linear trends from the saddle between the east fork of Any Creek and Treasure Creek through the main body of the geochemical anomaly. Cross-cutting faulting is indicated by a sharp break in slope, suggestive of a fault scarp, that runs north-northeast through the anomalous area. Rock geochemistry on float fragments of the intrusive that were found in the soil pits indicates as much as 250 ppb gold. In a trench sample, rare quartz-stibnite-veined schist contains 6,050 ppb gold, 4.4 percent antimony, 2 ounces of silver per ton, and 758 ppm arsenic. Another specimen of silicified schist from the same location that is cross-cut by vuggy crustiform quartz veins contains 4,610 ppb gold, 4,601 ppm arsenic, 98 ppm antimony, and 3.5 ppm silver. Silicification and quartz veining are widespread throughout the anomaly. Iron staining, clay alteration, and bleaching of schist are noted in soil pit schist fragments. The quartz porphyry that marks the north edge of the anomaly is silicified and vuggy, and limonite fills vugs locally (Dashevsky, 1993).
Workings: In the 1970's, Cantu Minerals conducted a soil-geochemistry survey of the area. In the 1980's, Tri-Con Mining, Inc. (the operating arm of CAN-EX Resources Inc.) reanalyzed some of the old soil sample pulps for gold and conducted some trenching. In 1990, American Copper and Nickel Company assumed interest in the Eagle Creek properties and sampled existing trenches and check-sampled across the previously defined gold-arsenic soil anomaly (Dashevsky, 1993).
Alteration: Silicification and quartz veining are common in rock fragments found throughout the anomaly, as well as iron staining, clay alteration, and bleaching of schist. The quartz porphyry that marks the north edge of the anomaly is silicified and vuggy, and limonite fills vugs locally (Dashevsky, 1993).

Commodities (Major) - Au
Development Status: None
Deposit Model: Schist-hosted gold- and antimony-bearing quartz veins.

Other Databases

Link to USGS - Alaska:	FB074

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References