|Quadrangle map, 1:250,000-scale||MH|
|Quadrangle map, 1:63,360-scale||A-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is on the north side of Powell Gulch about 0.7 mile northeast of its mouth. It is about 0.3 mile east of the center of section 35, T. 20 S., R. 15 E.|
This record specifically describes the mineralization at this site as reported by Nokleberg and others (1991) and Bittenbender and others (2007). However, the work is within several generations of large block of claims and exploration that not only covers this site but several other sites nearby, notably ARDF sites MH380 and MH365. Those records may include data that applies to this site.
C.W. Monroe prospected in the area from 1964 to at least 1973 and staked more than 142 lode claims that covered this site and several square miles south of Chisna Pass (Bittenbender and others, 2007). Paul Glavinovich staked at least 36 claims in the area that may have covered this site and Resource Associates of Alaska (RAA) staked a large block of claims in the late 1970s and early 1980s that probably covered this site. The location of three holes that RAA drilled is uncertain but they were probably about 0.5 mile north at ARDF site MH365. AMAX Exploration was apparently active in the area in about 1990 and Cominco Alaska Exploration explored in the early 90s. In 2010, Corvus Gold Inc. drilled three holes about 0.5 mile to the north at ARDF site MH365 as part of an extensive regional exploration program (Taylor, 2010). Their work included surface sampling and mapping and geochemical and geophysical surveys that undoubtedly covered this prospect.
As described by Bittenbender and others (2007) citing Nokleberg and others (1992 [MF]; 1992 [Open-File]), the rocks in the area consist of hypabyssal Permian andesite to rhyolite, stocks, dikes, and sills that intrude marine volcanic rocks, volcaniclastic sedimentary rocks, and thin limestones of the Pennsylvanian and Permian, Slana Spur Formation. The area is cut by a series of high angle faults.
Rose (1967) did not visit the site but was shown specimens of chalcopyrite replacing silicified limestone. Nokleberg and others (1991) identified a skarn-like deposit about 75 feet wide and 270 feet long that parallels a dip slope. Veins as much as about 3 feet wide of chalcopyrite and massive hematite cut garnet skarn in limestone. A grab sample of chalcopyrite-bearing rock assayed 1.5 percent copper, 100 parts per million (ppm) tungsten, and 7 ppm silver.Bittenbender and others (2007) described a steep, south-dipping, northwest-trending zone of near-massive specular hematite with disseminated chalcopyrite. The zone can be traced for at least 500 feet along strike and it is it up to 30 feet thick. A 20-foot sample across the hematite band averaged 3,770 ppm copper, 11.7 percent iron, and 428 ppm zinc. The hematite zone is underlain by limestone and overlain by volcaniclastic sedimentary rocks. Small outcrops of epidote-garnet-hematite skarn. are nearby. A 5-foot sample contained up to 2.89 percent copper, 776 ppm zinc, and more than 15 percent iron. The highest gold value was only 22 ppb. Bittenbender and others (2007) suggest that the mineralization is related to a 300.4 +/- Ma quartz monzonite intrusion nearby.
|Geologic map unit||(-144.814026105429, 63.1367023238256)|
|Mineral deposit model||Hematite layer with disseminated chalcopyrite; copper-iron skarn (Cox and Singer, 1986; model 18b).|
|Mineral deposit model number||18b|
|Age of mineralization||Early Permian or younger.|
|Alteration of deposit||Small outcrops of mineralized skarn.|
|Workings or exploration||C.W. Monroe prospected in the area from 1964 to at least 1973 and staked more than 142 lode claims that covered this site and several square miles south of Chisna Pass (Bittenbender and others, 2007). Paul Glavinovich staked at least 36 claims in the area that may have covered this site and Resource Associates of Alaska (RAA) restaked a large block of claims in the late 1970s and early 1980s that almost certainly covered this site. The location of the three holes RAA drilled is uncertain but they were probably about 0.5 mile north at ARDF site MH365. AMAX Exploration was apparently active in the area in about 1990 and Cominco Alaska Exploration explored in the early 90s. Corvus Gold Inc. drilled three holes about 0.5 mile north ARDF site MH365 as part of an extensive exploration program. The work included surface sampling and mapping and geochemical and geophysical surveys on a large block of claims that undoubtedly covered this prospect. Examined and sampled by several state and federal minerals agencies.|
|Indication of production||None|
Bittenbender, P.E., Bean, K.W., Kurtak, J.M., and Deininger, James Jr., 2007, Mineral assessment of the Delta River Mining District area, east-central, Alaska: U.S. Bureau of Land Management, Alaska Technical Report 57, 675 p.
Nokleberg, W. J., Aleinikoff, J. N., Dutro, J. T., Lanphere, M. A., Silberling, N. J., Silva, S. R., Smith, T. E., and Turner, D. L., 1992, Map, tables, and summary of fossil and isotopic age data, Mount Hayes Quadrangle, eastern Alaska range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1996-D, 43 p., 1 sheet, scale 1:250,000.
Nokleberg, W.J., Aleinikoff, J. N., Lange, I. M.; Silva, S. R., Miyaoka, R. T., Schwab, C. E., Zehner, R. E., Bond, G. C., Richter, D. H., Smith, T. E., and Stout, J. H., 1992, Preliminary geologic map of the Mount Hayes quadrangle, eastern Alaska Range, Alaska: U.S. Geological Survey Open-File Report 92-594, 39 p. 1 sheet, scale 1:250,000.
Nokleberg, W.J., Lange, I.M., Roback, R.C., Yeend, Warren, and Silva, S.R., 1991, Map showing locations of metalliferous lode and placer mineral occurrences, mineral deposits, prospects, and mines, Mount Hayes quadrangle, eastern Alaska Range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1996-C, 42 p., 1 sheet, scale 1:250,000.
Rose, A.W., 1967, Geology of the upper Chistochina River area, Mount Hayes quadrangle, Alaska: Alaska Division of Mines and Minerals Geologic Report 28, 41 p., 2 maps, scale 1:40,000.
Taylor, Chris, 2010, Technical report on the Chisna copper gold project, Chistochina mining district, south-central Alaska: Unpublished technical report for International Tower Hill Mines Ltd., 107 p. (posted on www.sedar.com, July 15, 2010).
|Reporters||W.T. Ellis (Alaska Earth Sciences), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS); D.J. Grybeck (Contractor, USGS)|
|Last report date||5/13/2012|