|Quadrangle map, 1:250,000-scale||CH|
|Quadrangle map, 1:63,360-scale||C-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Kiska prospect is along the ridge top about 0.9 mile south-southwest of Little Squaw Peak. It is near the southeast corner of section 4, T. 31 N., R. 3 W. The Chiga prospect is about 1,500 feet north of the Kiska prospect. The coordinates are for the Kiska prospect and the locations are accurate.|
Placer gold was discovered in the Chandalar area on Little Squaw Creek (CH039) in 1902 (Barker, and Bundtzen, 2004; Barker, 2007; Barker and others, 2009). By 1909, four quartz veins and many more were located prior to WWI. Most of the important properties in the district were consolidated by William Sulzer from 1909 to 1941; the Mikado Mine was one of the prominent deposits of the Chandalar area and was included. Those properties were taken over in 1946 to form the Little Squaw Mining Company in 1959, which in turn became the Little Squaw Gold Mining Company in 1968. From 1967 to 1999, Little Squaw Gold Mining Company leased some of their Chandalar lode and placer ground for mining and/or exploration to a succession of companies, notably the Chandalar Gold Mining and Milling Company (1967-1971), Noranda Mining (1974-1976), the Chandalar Development Corporation (1980-1983), and Gold Dust Mines (1989-1999). There was some earlier small lode production from the district but the first documented gold produced from the lodes was 870 ounces produced from 1967 to 1971 from the Mikado and Summit mines by the Chandalar Gold Mining and Milling Company. Subsequently, Chandalar Development produced 8,169 ounces of lode gold from the Mikado and Summit Mines but recovery was poor. In 2003, Little Squaw Gold Mining Company and its direct descendent Goldrich Mining Company began an aggressive exploration program for lode and placer deposits over a large block of land that covers almost all of the known deposits in the Chandalar area and in early 2010, that effort continued (Goldrich Mining Company, 2010).
The geology of the Chandalar area is dominated by a system of west-northwest-trending regional faults including a prominent thrust fault in the southern part of the district and a series of major high-angle faults through the center of the area (Bundtzen and Laird, 2009a, 2009b). These faults separate the rocks into two principal units, a west-northwest-trending Upper Plate unit about 3 miles wide in the center of the area and a Lower Plate unit to the north and south. The contact of the two units is a thrust fault on the south side of the Upper Plate rocks and a high-angle fault on the north side. Most of the Upper Plate rocks consist of Devonian upper-greenschist-facies metamorphic rocks, mainly carbonaceous schist; quartz-chlorite-muscovite schist, schist and phyllite derived from turbidites that comprise the Mikado Phyllite, metamorphosed calcareous sandstone, and quartz-muscovite schist. The Lower Plate rocks consist of Devonian, upper-greenschist-facies metamorphic rocks, mainly metamorphosed volcanic agglomerate, chlorite-rich tuffaceous schist, quartz-mica schist derived from mudstone, mica-quartz schist, and quartzite. Both the Upper and Lower Plate rocks are cut by irregular masses, dikes and sills of greenstone, metagabbro, and metadiorite of unknown age. Most of the mineral deposits in the Chandalar area are in the Upper Plate rocks and the deposits often are along the regional, steep-to-vertical, west-northwest-trending faults. There is an additional conjugate set of north-northeast-trending faults that offset the Upper Plate rocks and at least some of the mineralization may be localized at the intersections of the regional west-northwest-trending faults and the conjugate faults. The Kiska and Chiga prospect are in Upper Plate rocks near the contact of black, carbonaceous phyllite and schist of the Mikado Phyllite with muscovite-chlorite-quartz schist.
The Kiska and Star veins are typical of those in the district; they are gold quartz veins with a few percent sulfides, mainly arsenopyrite and some galena. Barker (2007) show that both the Kiska and Star veins trend west- northwest, i.e., parallel to the regional faults in the district that often control the mineralization.
No rocks crop out at the Kiska prospect and the old trenches that probably date to before WWII have sloughed (Barker, 2007). Two veins were identified by float of quartz vein and breccia material spread over an area about 1,600 feet long and up to 600 feet wide. The veins strike west-northwest. Fine gold can be panned from the frost boils in the vicinity of the veins and soil sampling shows strong gold and arsenic anomalies over the veins. The fine fraction of soil collected over the veins contained 0.4 to more than 2 parts per million (ppm) gold. Seven holes were drilled on the prospect in 2006. The drilling indicated that the mineralization is discontinuous and only a few short intercepts were cut that contained no more than 2 parts per million gold. After the drilling, a trench was dug over one of the drill holes. Discontinuous pods and lenses of weathered quartz were exposed. One sample contained 422 ppm gold. Another assayed 0.378 ppm gold but when reanalyzed by a metallic-screen assay, it assayed 71.7 ppm gold. The Kiska veins were traced for about 2,500 feet as a magnetic low.
Just north of the Kiska prospect, lenses of black dolomite are found along a fault zone. The dolomite appears to be hydrothermal and samples contain anomalous arsenic.The nearby Chiga prospect is covered by thick alluvium, talus, and solifluction lobes. Some quartz float is on the surface and soil samples had up to 242 ppm antimony. One trench was cut on the Chiga prospect. One interval in an intensely altered shear zone averaged 1.1 ppm gold across 24 feet. Pods of massive stibnite occur along a fault zone. The Chiga gold and antimony soil anomalies can be traced for 3,200 feet. The high antimony values suggest a style of mineralization that is different from the other vein deposits in the Chandalar district. Most of the veins in the Chandalar district are considered mesothermal (Barker and Bundtzen, 2004) by comparison with similar deposits elsewhere and in consideration of the fluid inclusion and oxygen and lead isotope studies of the Chandalar mineralization (Ashworth, 1983, 1984; Rose and others, 1988; Gacetta and Church, 1989). However, the Chiga may be epithermal.
|Geologic map unit||(-148.218732077232, 67.5343168146585)|
|Mineral deposit model||Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a; stibnite vein (Cox and Singer, 1986, model 27d).|
|Mineral deposit model number||36a, 27d|
|Age of mineralization||Possibly Middle Cretaceous based on the assertion of Dillon (1982) that the gold-quartz veins of the central Brooks Range are that age. However, there is no definitive data for the age of the veins of the Chandalar area.|
|Alteration of deposit||Not noted specifically. The mineralization is associated with fault zones that have much gouge and clay.|
|Workings or exploration||Several old hand-dug prospect pits and trenches that probably date to before WWII. Soil and geophysical surveys, 7 drill holes, and several trenches in 2006.|
|Indication of production||None|
Ashworth, Kate, 1983, Genesis of gold deposits at the Little Squaw Mines, Chandalar Mining District, Alaska: Unpublished Masters of Science Thesis, Western Washington University, Bellingham, 98 pages.
Ashworth, (Lamal) Kate, 1984, Fluid inclusion study of the Eneveloe Vein, Chandalar Mining District: Private Report, Chandalar Development Associates, 8 pages (in files of the Goldrich Mining Company.
Barker, J.C., 2006, Chandalar Mining District, a report of findings and recommendations, 2005: Unpublished report for Little Squaw Gold Mining Company, 93 p. (on the Internet at http://www.goldrichmining.com/Files/corporate/2005AnnualReport011906.pdf, as of February 14, 2010).
Barker, J.C., 2007, Chandalar Mining District, Annual Report of findings for 2006; Unpublished report for Little Squaw Gold Mining Company, 124 p. (On the Internet at http://www.goldrichmining.com/Files/chandalar/chandalar_barker_rpt_2007.pdf, as of February 14, 2010).
Barker, J.C., and Bundtzen, T.K., 2004, Gold deposits of the Chandalar Mining District, Northern Alaska: An information review and recommendations: Unpublished report for the Little Squaw Gold Mining Company, 165 p. (in the files of Goldrich Mining Company).
Barker, J.C., Murray, R.B., Keener, J.O., and Martin, P.L., 2009, Evaluation of the Chandalar mining property: Unpublished report prepared for Goldrich Mining Company, 165 p. (on the Internet at http://www.goldrichmining.com/Files/chandalar/Chandalar_tech_rept_4_15_09.pdf, as of February 14, 2010).
Bundtzen, T.K., and Laird, G.M., 2007a, Geologic map of the Chandalar Mining District, Brooks Range, Northern Alaska, 2007: Unpublished map prepared for Little Squaw Gold Mining Company, 1 sheet, scale 1:20,000. (on the Internet at https://www.goldrichmining.com/media/downloads/technical_reports/regional_chandalar_geo_map_final_07.pdf (last accessed March 2018).
Buzzell, R.G., 2007, History of the Caro-Coldfoot trail (RST 262) and the Coldfoot-Chandalar trail (RST 9): Alaska Office of History and Archaeology, Report 17, 138 p.
Chipp, E.R., 1970, Geology and geochemistry of the Chandalar area, Brooks Range, Alaska: Alaska Division of Geological and Geophysical Surveys Geologic Report 42, 39 p., 1 sheet, scale 1:3,000.
Dillon, J.T., 1982, Source of lode and placer gold deposits of the Chandalar and upper Koyukuk Districts: Alaska Division of Geological and Geophysical Surveys Open-File Report AOF-158, 25 p., 1 sheet, scale 1:250,000.
Gacetta, J.D., and Church, S.E., 1989, Lead isotope data base for sulfide occurrences in Alaska, December, 1989: U.S. Geological Survey Open File report 89-688, 59 pages.
Goldrich Mining Company, 2010, Chandalar, Alaska; Project overview: http://www.goldrichmining.com/pages/prop_chan_over.htm (as of February 16, 2010).
Rose, S.C., Pickthorn, W.J., and Goldfarb, R.J., 1988, Gold mineralization by metamorphic fluids in the Chandalar Mining District, southern Brooks range-fluid inclusion and oxygen isotopic evidence, in, Galloway, J.P., and Hamilton, T.D., eds., Geologic studies in Alaska by the U.S. Geological Survey during 1987: U.S. Geological Survey Circular 1016, p. 81-84.
|Reporters||D.J. Grybeck (Contractor, U.S. Geological Survey)|
|Last report date||4/2/2010|