| Quadrangle map, 1:250,000-scale | MM |
|---|---|
| Quadrangle map, 1:63,360-scale | C-2 |
| Latitude | 63.5732 |
| Longitude | -150.8869 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | Twentytwo Gulch (Cobb, 1980 [OFR 80-363]) rises between Wickersham Dome and an unnamed dome about one mile east of Wickersham. The gulch has one named tributary, the West Fork. Twentytwo Gulch flows north and enters Glacier Creek about a mile above Eighteen Gulch and a mile below Yellow Pup. The location is about 0.2 mile above the confluence of the gulch with Glacier Creek, and marks the part of Twentytwo Gulch that has been placer mined. Twentytwo Gulch (sometimes called Wickersham Creek) is number 49 of Cobb (1972 [MF 366]), and is included with Glacier Creek in location 54 of MacKevett and Holloway (1977). |
Geologic descriptionTwenty-two Gulch flows through a relatively narrow and fairly steep canyon. The stream gradient is about 500 feet per mile in the main part of the creek and it steepens in the upper reaches. The upper canyon cuts into rocks of the Spruce Creek sequence; the lower part cuts into Birch Creek Schist (Thornsberry, McKee, and Salisbury, 1984). The creek was rich enough to work by hand and yielded considerable placer gold (Wells, 1933, p. 371). Lode deposits in the walls of the creek, such as those at the Florence prospect (MM082) and Bosart mine (MM074), could have furnished some of the gold, along with the galena and stibnite reported in the placer concentrates. Gravel at the junction of Twenty-two Gulch and Glacier Creek was placer mined in 1983. The mine processed gravel from both creeks in a deposit 3 to 6 feet thick. The gold was rudely to coarsely crystalline, and sometimes dendritic; nuggets in the 1/4 to 1/2 ounce range were common. The concentrates contained galena, stibnite, garnet, and tourmaline (Wells, 1933; Levell, v. 2, p. 50-51). | |
| Geologic map unit | (-150.889188578286, 63.5726952247744) |
|---|---|
| Mineral deposit model | Au-PGE placer (Cox and Singer, 1986; model 39a). |
| Mineral deposit model number | 39a |
| Age of mineralization | Holocene. |
| Workings or exploration | Twentytwo Gulch (then called Wickersham Creek) was mined by hand as early as 1920, and then intermittently through the 1930s (Brooks, 1922; Davis, 1923; Cobb (1980 [OFR 80-363]). Mechanical mining began on a small scale in about 1950. During 1983, a small mechanical operation processed gravel both from lower Twentytwo Gulch and adjacent Glacier Creek (Levell, 1984, v. 2). |
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| Indication of production | Yes; small |
| Reserve estimates | Relatively rich placer gravel probably remains in previously mined sections and in side pay along Twentytwo Gulch. Because the canyon is narrow, the deposits are not large. Levell (1984, v. 2, p. 50-51) believed that the gulch contains a 'very high grade placer resource,' one that could support a small- to medium-scale operation. |
| Production notes | About 1000 ounces of gold was recovered from Twentytwo Gulch (Cobb, 1980 [OFR 80-363]). In 1983, an operation at the mouth of the creek produced at least 200 ounces, some of probably was recovered from Glacier Creek. |
Additional commentsTwentytwo Gulch is in Denali National Park and Preserve. | |
| MRDS Number | A011278 |
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References | |
| Reporters | C.C. Hawley |
| Last report date | 4/22/2001 |