Kisa Breccia

Prospects, Undetermined

Alternative names

Golden Dyke

Commodities and mineralogy

Main commodities As; Au
Other commodities Ag; Bi; Cu; Mo; Te; W
Ore minerals pyrite
Gangue minerals carbonate; quartz

Geographic location

Quadrangle map, 1:250,000-scale BH
Quadrangle map, 1:63,360-scale B-1
Latitude 60.3546
Longitude -159.3011
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Kisa Breccia prospect is about 0.3 mile north-northwest of peak 3690 and about 2.3 miles north of the narrow channel between the two basins of Kisaralik Lake. It is about 0.3 mile north of the center of section 14, T. 3 N., R. 58 W., of the Seward Meridian. This location is probably accurate. The exact location of the Golden Dyke prospect is uncertain but it is nearby.

Geologic setting

Geologic description

Gold Crest Mines Inc. (2011 [Kiska summary]) has explored a poorly exposed, extensively carbonate-sulfide altered breccia body along a ridge crest and on steep, north-facing slopes by surface mapping and sampling, geophysical surveys, and drilling. The breccia is composed of altered sedimentary and igneous clasts, many of which show multiple generations of veining and brecciation. The breccia is exposed over an area about 500 meters by 300 meters, a vertical distance of about 250 meters. Rock chips collected systematically of the breccia averaged more than 1.25 grams of gold per tonne; some samples contained up to 7 grams of gold per ton (Gold Crest Mines Inc., 2011 [Kiska rock chip]). Several types of igneous rocks form clasts in the breccia and the breccia may represent the top of a mineralized stock. Gold Crest drilled 5 holes in the breccia totaling more than 940 meters (Gold Crest Mines Inc., 2011 [Kiska drill holes]). Some notable intercepts were: 206 meters with an average grade of 0.3 gram of gold per tonne; 115 meters with an average grade of 0.7 gram of gold per tonne; 44 meters with an average grade of 1.13 gram of gold per tonne, and several intercepts of more than 2 meters that averaged up to 0.25 ounce of gold per ton. The sulfides are not specified.
The U.S. Geological Survey visited the site earlier and collected several samples of pyrite-bearing rhyolite dikes and sulfide-bearing quartz veins (Frost, 1990; Box and others, 1993). Rock samples from a large, red-weathering area, which possibly is the Kisa prospect, contained up to 0.41 parts per million (ppm) gold, 1.5 ppm silver, 7,000 ppm arsenic and 100 ppm antimony.
The rocks in the area are Jurassic marine, volcaniclastic sandstone, conglomerate, and argillite; no nearby plutonic rocks are mapped by Box and others (1993).
The exact location of the Golden Dyke prospect is unknown but it is nearby (Gold Crest Mines Inc., 2011 [Golden Dyke summary]). As described by Gold Crest Mines Inc. (2011), the mineralization at this prospect consists of numerous, altered, silica-carbonate-sulfide rhyolite dikes and sills. More than 20 dikes and sills are known that vary from about 3 feet thick to over 30 feet thick; many pinch and swell and locally form small stock-like bodies. Rock chips were collected systematically from the dikes and altered sandstone, allowing for the steep and rugged terrain. The samples contained up to 0.18 ounce of gold per ton, major arsenic, up to 328 ppm antimony, 57 ppm bismuth, 45 ppm molybdenum, 6 ppm silver, 1 percent copper, 30 ppm tellurium, and 48 ppm tungsten (Gold Crest Mines Inc., 2011 [Golden Dyke rock chip]).
Geologic map unit (-159.303353928206, 60.3538669710081)
Mineral deposit model Mineralized breccia and rhyolite dikes with gold values.
Age of mineralization Jurassic or younger based on the age of the host rock. May be related to a buried pluton, many of which in the region are Late Cretaceous or Early Tertiary (?) (Box and others, 1993).
Alteration of deposit Extensive carbonate-sulfide alteration in mineralized breccia; rhyolite dikes nearby have silica-carbonate-sulfide alteration.

Production and reserves

Workings or exploration Considerable surface mapping and sampling; aerial geophysical surveys; and 5 holes drilled at the Kisa prospect.
Indication of production None

References

MRDS Number 10307259

References

Gold Crest Mines Inc., 2011, Golden Dyke prospect, cross sections: http://www.Gold Crestminesinc.com/downloads/alaska/southern/GoldenDyke_CrossSections.pdf (as of Feb. 11, 2011).
Gold Crest Mines Inc., 2011, Golden Dyke target [summary}: http://www.Gold Crestminesinc.com/projects/alaska/kisa-golden-dyke.asp (as of February 11, 2011).
Gold Crest Mines Inc., 2011, Kisa Breccia target 2007 drill hole locations: http://www.Gold Crestminesinc.com/downloads/alaska/southern/Kisa_Drill_Plan.pdf (as of Feb 11, 20111)
Gold Crest Mines, Inc., 2011, Kisa Breccia Target, E-W cross section: http://www.Gold Crestminesinc.com/downloads/alaska/southern/Kisa_Cross_Sections.pdf (as of February 11, 2011)
Gold Crest Mines Inc., 2011, Kisa Breccia target, rock chip geochemistry: http://www.Gold Crestminesinc.com/downloads/alaska/southern/Kisa_Rock_Chip.pdf (as of Feb. 11, 2011)
Gold Crest Mines Inc., 2011, Kisa Breccia target [summary]: http://www.Gold Crestminesinc.com/projects/alaska/kisa-breccia.asp (as of Feb 11, 2011)
Reporters Travis L. Hudson (Applied Geology); D.J. Grybeck (Contractor, USGS)
Last report date 2/28/2011