Crash

Prospect, Active

Alternative names

Sheep Creek 2
BMP

Commodities and mineralogy

Main commodities Ag; Cu; Zn
Other commodities Au; Pb
Ore minerals chalcopyrite; galena; malachite; pyrrhotite; sphalerite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MG
Quadrangle map, 1:63,360-scale B-2
Latitude 62.353
Longitude -153.8015
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Crash prospect is located in an unnamed east-flowing tributary of Sheep Creek. It is 4.0 kilometers northwest of Smith Lake at an elevation of 2,800 feet in the SW1/4 sec. 7, T. 26 N., R. 24 W., of the Seward Meridian.

Geologic setting

Geologic description

The Crash prospect consists of two siliceous, cataclastic breccias similar to those that host the mineralization at the Dahl prospect (MG053). The Crash zone is in a splay structure associated with a regional fault that hosts the Dahl prospect (MG053). The mineralization in one shale-hosted breccia zone contains massive chalcopyrite and sphalerite with traces of galena. It is near the contact of the Lower Ordovician to Lower Silurian, Post River Formation and the Middle to Upper Silurian Terra Cotta Mountains Sandstone, both units of the Dillinger sub-terrane (Bundtzen, Harris, and Gilbert, 1997). The other cataclastic breccia contains abundant arsenopyrite. Both sulfide-bearing breccia zones are from 3 to 30 centimeters thick, appear stratiform or parallel to sedimentary bedding, and are isoclinally folded. This suggests the sulfides were formed prior to Lower Cretaceous compressive deformation (Bundtzen, Harris, and Gilbert, 1997). The mineralization at the Crash prospect might be related to younger plutons. Samples from the larger sulfide-bearing breccia contain up to 16.5 percent copper and 926.8 grams of silver per tonne. (Brewer and others, 1992). The smaller cataclastic zone has a pod 02 to 2.0 meters thick of massive arsenopyrite that contains 6.8 grams of gold per tonne. Three samples collected by Smith and Albanese (1985) contain up to 316 parts per million (ppm) copper, 86 ppm lead, 940 ppm zinc, and 10.5 grams of silver per tonne. The gold in the Crash is atypical of most sulfide occurrences and prospects in the Farewell Mineral Belt.
In 2008, this prospect was one of several in a block of claims that covered more than 70 square miles, known collectively as the BMP project (International Tower Hill Mines, Ltd., 2008).
Geologic map unit (-153.803721826935, 62.3523879918348)
Mineral deposit model Either sedimentary exhalative lead-zinc or polymetallic vein (Cox and Singer, 1986; model 31a or 22c).
Mineral deposit model number 31a or 22c
Age of mineralization Undated; inferred to be Lower Ordovician to Lower Silurian, based on graptolites found in mineralized area (Bundtzen, Harris, and Gilbert, 1997).

Production and reserves

Workings or exploration Tom Smith and Mary Albanese first sampled the Sheep Creek-2 occurrence in 1982 during mineral investigations by the Alaska Division of Geological and Geophysical Surveys (Smith and Albanese, 1985). As of 2008, the prospect was within a large block of claims called the BMP project by International Tower Hill MIne, Ltd. (2008).
Indication of production None

References