|Quadrangle map, 1:250,000-scale||NL|
|Quadrangle map, 1:63,360-scale||A-6|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Silver Chalice prospect is about 1 mile west of the Yukon River, and 3 miles east of Poison Creek. The coordinates are for the approximate center of the prospect near VABM Kaiyah in section 24, T. 16 S., R. 1 W. The location is accurate.|
The rocks in the area of the Kaiyah prospect consist of Cretaceous deltaic sandstone, shale, and conglomerate adjacent to the Poison Creek caldera. The caldera is expressed topographically as a curvilinear fault contact between the volcanic rocks inside the caldera and Koyukuk sedimentary rocks around it. Landsat and magnetic data suggest that the caldera system may be over 20 kilometers in diameter. The Tertiary volcanic rocks include intermediate to felsic ash flow tuff, massive basaltic andesite, and a small area of siliceous sinter (North Star Exploration, Inc., 2001; Patton and others, 2009).
Gold and silver are anomalous in surface samples of silicified sedimentary rocks east of the caldera rim in an area of radial faulting. The silicified rocks are cut by chalcedonic quartz veinlets, vuggy drusy coatings, and blue-gray quartz veinlets. In addition to the silicification, the host rocks locally are argillized (clay altered). Core holes drilled in 2000 intersected extensive zones of polyphase quartz veining, advanced argillic alteration, polymetallic sulfides, and mineralized dikes. The drill holes were targeted at two east-west-trending vein systems, the Main and South veins, which are approximately 250 feet apart (Avalon Development newsletter, Jan., 2001).
Bundtzen and Miller (1997) first reported gold in epithermal quartz veins at the prospect in 1997. Subsequent fieldwork by North Star Exploration Inc. in 1999 resulted in the definition of more widespread mineralization. In 250 rock samples, gold averages 110 parts per billion (ppb) and silver averages 20 parts per million (ppm). Samples contain up to 0.4 ppm gold and up to 13.6 ounces of silver. Samples also contain anomalous values of arsenic, bismuth, and mercury (North Star Exploration, Inc., 2001).Next Gen Metals Inc. (2009) acquired the property in late 2009. As described by them, the quartz veins are associated with northeast structures that radiate from the margin of the caldera. The veins are in an outer zone of propylitic alteration and an inner zone of weak to moderate argillic alteration; there also is weak silicification adjacent to the veins. Rock samples from surface rubble contain up to 10 grams of gold per tonne and 462 grams of silver per tonne; the gold:silver ratio is about 40:1. The main Silver Chalice vein is up to 25 feet thick as cut in two drill holes; the South vein is 27 feet thick as cut in one hole. Fluid inclusion work suggests an epithermal origin.
|Geologic map unit||(-158.773463931439, 64.0822228674932)|
|Mineral deposit model||Epithermal Au-Ag (Cox and Singer, 1986; model 25c).|
|Mineral deposit model number||25c|
|Age of mineralization||The veins cut Tertiary volcanic rocks.|
|Alteration of deposit||Silicification, propylitic and argillic alteration.|
|Workings or exploration||During 1999 and 2000, North Star Exploration Ltd. explored the Kaiyah prospect with geologic mapping, geophysics, and Landsat image analysis. In 2000, 2,776 feet of core drilling were completed. Next Gen Metals Inc. acquired the property in late 2009 and plans extensive work in 2010.|
|Indication of production||None|
Additional commentsThis prospect is on Doyon, Ltd. selected land.
Bundtzen, T.K., and Miller, M.L., 1997, Precious metals associated with Late Cretaceous-early Tertiary igneous rocks of southwestern Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 242-286.
Next Gen Metals Inc., 2009, Next Gen acquires the Silver Chalice prospect, Alaska: http://www.nextgenmetalsinc.com/i/pages/120909N.htm (News release, December 7, 2009).
North Star Exploration, Inc., 2001, Kaiyah epithermal Au-Ag prospect, 2000, promotional pamphlet, 4 p.
|Reporters||C.E. Cameron (Northern Associates Inc.); D.J. Grybeck (Contractor, U.S. Geological Survey)|
|Last report date||4/2/2010|