Gulch Creek No. 2

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals arsenopyrite; gold; pyrite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale D-7
Latitude 60.7762
Longitude -149.3321
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is located in the NE1/4 section 19, T. 8 N., R. 1 E., of the Seward Meridian. It is situated at the head of a small cirque valley on the south side of Gulch Creek, at elevations between 3,200 and 3,350 feet. This is location S-283 of Jansons and others (1984). The location is accurate to within a quarter of a mile.

Geologic setting

Geologic description

The Gulch Creek No. 2 occurrence consists of at least two subparallel quartz-carbonate veins that strike N55-60E and dip 45-50SE. The veins average 1.5 feet thick and are locally as much as 4 feet wide. They can be traced for 100 to 200 feet along strike. The quartz has a well-developed ribbon structure, is highly fractured, and contains arsenopyrite and minor pyrite along the contact with the wallrock. Slickensides along the hanging wall of one vein are horizontal and indicate a right-lateral movement (Hoekzema and Sherman, 1983). The Valdez Group (Late Cretaceous age) host rock (Nelson and others, 1985) is mostly highly fractured slate and metasiltstone having foliation that strikes N30-35E and dips 55-60SE (Hoekzema and Sherman, 1983). Five samples were collected by the U.S. Bureau of Mines in 1982.; they assayed trace amounts of gold and as much as 0.01 ounce of silver per ton (Jansons and others, 1984).
Geologic map unit (-149.334258919132, 60.775639760944)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Cretaceous or younger; the veins cut rocks of the Valdez Group of Late Cretaceous age.

Production and reserves

Workings or exploration No workings or improvements are present. The occurrence was discovered by the U.S. Bureau of Mines in 1982; at that time they examined and sampled two veins (Hoekzema and Sherman, 1983). The five samples they collected assayed trace amounts of gold and as much as 0.01 ounce of silver per ton (Jansons and others, 1984).
Indication of production None

References

References

Reporters Jeff A. Huber (Anchorage)
Last report date 2/6/2000