Surprise

Prospect, Inactive

Commodities and mineralogy

Main commodities Ag; Au
Other commodities As; Cu; Hg; Pb; Zn
Ore minerals gold; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale PM
Quadrangle map, 1:63,360-scale A-2
Latitude 55.19
Longitude -160.656
Nearby scientific data Find additional scientific data near this location
Location and accuracy The map site of the Surprise prospect is at an elevation of 600 feet, about 1,500 feet north-northwest of the center of sec. 3, T. 58 S., R. 75 W., Seward Meridian. The location is accurate to within 1,200 feet.

Geologic setting

Geologic description

The Surprise vein is approximately 10 feet in width and is composed of massive and comb quartz containing 0.5 to 3.0 percent pyrite. It strikes northeast and can be followed for 1,000 feet as a magnetic low (Trujillo and others, 1981). This previously unknown vein was penetrated in the upper part of a drill hole positioned to test another vein at depth. Host rocks are propylitized and argillized andesite flows of the late Eocene to early Oligocene Popof volcanic rocks (Wilson and others, 1995).
The drill hole cut an upper 7.9 feet grading 0.012 ounce of gold and 0.07 ounce of silver per ton. A lower 3.7-foot intercept graded 0.05 ounce of gold and 0.04 ounce of silver per ton. These core intervals also assayed as much as 160 ppm copper, 90 ppm lead, 625 ppm zinc, 100 ppm arsenic, and 0.27 ppm mercury (Trujillo and others, 1981).
Geologic map unit (-160.658067193303, 55.1891636642742)
Mineral deposit model Epithermal gold vein
Age of mineralization Eocene of younger.
Alteration of deposit The host rocks exhibit propylitic and argillic alteration.

Production and reserves

Workings or exploration In 1981, Resource Associates of Alaska explored this prospect by a 255-foot drill hole and several trenches. The best drill intercept was 3.7 feet grading 0.05 ounce of gold and 0.04 ounce of silver per ton (Trujillo and others, 1981).
Indication of production None

Additional comments

This prospect is located on land patented by, or interim-conveyed to, the Aleut Corporation.

References

References

Trujillo, R.S., Andersen, G.D., MacLeod, T., Hendrick, K., Farnham, S., Peterson, J., 1981. Exploration and evaluation of the Unga-Popof-Korovan Islands portion of lands leased from Aleut Native Corporation: Resource Associates of Alaska report, 70 p., 38 map sheets, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)
Reporters S.H. Pilcher
Last report date 2/1/2001