|Quadrangle map, 1:250,000-scale||SR|
|Quadrangle map, 1:63,360-scale||D-7|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Granite Creek is located in T. 8 N., R. 1 E., of the Seward Meridian. Granite Creek flows south within Turnagain Pass into East Fork Sixmile Creek. The map site of this placer occurrence is on Granite Creek at an elevation of about 800 feet. It is in the S1/2 section 27, T. 8 N., R. 1 E. The auriferous portion of Granite Creek is below Bertha Creek. This is location 149 of Cobb and Richter (1972), location 171 of MacKevett and Holloway (1977), location 21 of Tysdal (1978 [MF-880-B]), location 149 of Cobb and Tysdal (1980), and location P-74 of Jansons and others (1984). The location is accurate to within 300 feet.|
Granite Creek occupies a fairly wide valley over most of its length; bedrock is exposed in only a few locations. Below Bertha Creek (SR039) the valley is from about a quarter to a third of a mile wide and in many places is wet and marshy (Moffit, 1906). Gravel terraces are present, and the whole region appears to have been occupied by a lake or series of lakes at one time. Granite Creek is one of the largest tributaries of East Fork Sixmile Creek.
Near the mouth of Bertha Creek, Granite Creek contains about 8 to 10 feet of coarse gravel. These gravels were hydraulically mined in 1903 and 1904. Some of the mining may have been of Bertha Creek, but most of the gold probably came from Granite Creek. About 4 to 5 feet of finer alluvium, overlying the coarse gravel is also auriferous (Moffit, 1906). The gold is fine, bright yellow, and fairly smooth.Significant gravel deposits occur along much of Granite Creek.
|Geologic map unit||(-149.256547418284, 60.750333779594)|
|Mineral deposit model||Placer Au (alluvial) (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary.|
|Workings or exploration||
Gravel on Granite Creek near it confluence with Bertha Creek (SR039) was hydraulically mined in 1903 and 1904. Some of the mining may have been on Bertha Creek, but most of the gold probably came from Granite Creek. The value of the gold averaged about 15 cents per cubic yard (gold at $20.67 per ounce) (Moffit, 1906).
The early workings included a rock carrier driven by water power for handling the boulders and a small, homemade sawmill. The sawmill was an ordinary whipsaw set in a square upright frame and driven by a water wheel with suitable gear; it sawed three times as much in a day as two men can saw by hand (Moffit, 1906).The U.S. Bureau of Mines sampled Granite Creek in 1982 or 1983. Two suction dredge samples yielded 0.0007 and 0.0011 ounce of gold per hour. The gold was very fine grained, requiring amalgamation to recover.
|Indication of production||Yes; small|
|Reserve estimates||Jansons and others (1984) reported that significant gravel reserves occur but did not estimate an amount.|
|Production notes||A small amount of production from the mouth Bertha Creek (SR039) (Moffit, 1906) is believed to have actually come mostly from Granite Creek (Cobb and Tysdal, 1980).|
Cobb, E.H., and Richter, D.H., 1972, Metallic mineral resources map of the Seward quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-466, 2 sheets, scale 1:250,000.
Cobb, E.H., and Tysdal, R.G., 1980, Summaries of data on and list of references to metallic and selected nonmetallic mineral deposits in the Blying Sound and Seward quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-621, 276 p.
Jansons, Uldis, Hoekzema, R.B., Kurtak, J.M., and Fechner, S.A., 1984, Mineral occurrences in the Chugach National Forest, southcentral Alaska: U.S. Bureau of Mines Mineral Land Assessment 5-84, 218 p., 2 sheets, scale 1:250,000.
MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.
Martin, G.C., Johnson, B.L., and Grant, U.S., 1915, Geology and mineral resources of Kenai Peninsula, Alaska: U.S. Geological Survey Bulletin 587, 243 p.
Moffit, F.H., 1906, Gold fields of the Turnagain Arm region: U.S. Geological Survey Bulletin 277, p. 7-52.
|Reporters||Jeff A. Huber (Anchorage)|
|Last report date||6/25/2000|