Unnamed (at head of Limestone Creek) (ARDF #CH066) Ag, As, Au, Cu, Ni, Pd, Sb

Unnamed (at head of Limestone Creek)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Ag; As; Au; Cu; Ni; Pd; Sb
Ore minerals	chalcopyrite

Geographic location

Quadrangle map, 1:250,000-scale	CH
Quadrangle map, 1:63,360-scale	C-5
Latitude	67.6043
Longitude	-149.3897
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This occurrence is at the head of Limestone Creek, a tributary of the Bettles River. It is about 0.8 mile southeast of peak 4570, about 0.6 mile northwest of the center of section 17, T. 32 N., R. 8 W. The location is accurate to a quarter of a mile.

Geologic setting

Geologic description Nickel, palladium, and silver were reported in an X-ray analysis of rock from a thrust sheet in Devonian or Silurian, Skajit Limestone (Brosgé and Reiser, 1964). The occurrence is in a section of Skajit Limestone that has overridden Devonian(?) quartz muscovite schist along a major northeast-trending thrust fault. A later examination of the occurrence by Foley and others (1989) found no evidence of anomalous nickel, palladium, and silver in their sample, nor did Kurtak and others (2002). However, in their search for mineralization in the area, Kurtak and others (2002) found marble in outcrop nearby with 1 to 2 percent sulfides; a sample contained 1.3 parts per million (ppm) silver and 142 ppm arsenic. A float sample of marble with chalcopyrite was found about 1.5 miles upstream from the mouth of Limestone Creek; a sample contained 77 parts per billion gold, 3.3 ppm silver, 1.41 percent copper, and 109 ppm antimony.
Geologic map unit	(-149.39245471131, 67.6038952798297)
Mineral deposit model	Chalcopyrite in marble with low silver, gold, arsenic, and antimony values.
Age of mineralization	Silurian or younger based on the age of the marble host rock.
Alteration of deposit	Not specified.

Production and reserves

Workings or exploration	Only sampling by government agencies.
Indication of production	None
Reserve estimates	None.
Production notes	None.
Additional comments This prospect is on Doyon Ltd. selected lands; for more information, contact Doyon Ltd., Fairbanks, Alaska. MAS No. 0020310139

References

MRDS Number	A012144
References DeYoung, J.H., Jr., 1978, Mineral resources map of the Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-878-B, 2 sheets, scale 1:250,000. Dillon, J.T., Reifenstuhl, R.R., and, Harris, G.W., 1996, Geologic map of the Chandalar C-5 quadrangle, southeastern Brooks Range, Alaska: Alaska Division of Geological and Geophysical Surveys Professional Report 104, 2 sheets, scale 1:63,360. Foley, J.Y., Burns, L.E., Schneider, C.L., and Forbes, R.B., 1989, Preliminary report of platinum group element occurrences in Alaska: Alaska Division of Geological and Geophysical Surveys Public Data File 89-20, 32 p., 1 map sheet, scale 1:2,500,000. Heiner, L.E., and Wolff, E.N., eds., 1968, Mineral resources of northern Alaska, Final report, submitted to the NORTH Commission: University of Alaska, Mineral Industry Research Laboratory Report No. 16, 306 p. Kurtak, J.M., Klieforth, R.F., Clark, J.M., and Maclean, E.A., 2002, Mineral investigations in the Koyukuk mining district, northern Alaska, 2 vols.: Bureau of Land Management, Alaska Technical Report 50, 845 p. Maddren, A.G., 1913, The Koyukuk-Chandalar region, Alaska: U.S. Geological Survey Bulletin 532, 119 p.
Reporters	J.M. Britton (Anchorage, Alaska); D.J. Grybeck (Contractor, U.S. Geological Survey)
Last report date	4/18/2010