| Quadrangle map, 1:250,000-scale | AN |
|---|---|
| Quadrangle map, 1:63,360-scale | D-7 |
| Latitude | 61.824 |
| Longitude | -149.254 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | Near headwaters of Fairangel Creek, a tributary to Archangel Creek. Marked with quarry symbol and labeled 'Talkeetna Mine' on the Anchorage D-7 1:63,360-scale topographic map. Accurate within 400 ft. Locality 16 from Chaplin (1921, plate VI), locality 19 of Cobb (1972), and locality 16 of Mackevett and Holloway (1977). |
Geologic descriptionAlaskite dikes and younger, irregular quartz veins cut a coarse gray quartz diorite of the Late Cretaceous Willow Creek Pluton. The Willow Creek Pluton is a zoned pluton: the outer part consists of hornblende quartz diorite and lesser hornblende tonalite; the core consists of hornblende-biotite granodiorite, and lesser hornblende-biotite quartz monzodiorite and biotite quartz monzonite. The dikes have been described as both aplitic and pegmatitic and locally carry a few unnamed black minerals, hornblende, and tourmaline. The veins trend N 75 E and tend to pinch and swell. The veins that follow conjugate fractures in the quartz diorite are 12 to 18 inches thick, with a maximum width of 5 to 8 ft. The veins not following the dike contain considerable gold, averaging nearly 5 oz/ton Au. The pyrite in the veins have mostly been leached, leaving cubical cavities (Capps, 1915). A 30 inch thick vein follows the dike, but no reports of content are available (Brooks, 1925). Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954). A surface grab sample of the vein walls, collected by the U.S. Bureau of Mines, contained 0.57 g/ton Au (0.017 oz/ton Au) (Kurtak, 1986). | |
| Geologic map unit | (-149.256210113559, 61.8234725066453) |
|---|---|
| Mineral deposit model | Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a) |
| Mineral deposit model number | 36a |
| Age of mineralization | Late Cretaceous or younger; dikes and veins cut the Late Cretaceous Willow Creek Pluton. |
| Alteration of deposit | Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954). |
| Workings or exploration |
Explored by small open cuts and several hundred feet of underground workings in several adits. Development began in 1910 with two small open cuts, tunnelling planned for 1910-1911. Mining was reported from 1917-1923 and one tunnel was reported to be 500 ft long in 1923 (Brooks, 1925). A tramway once led from adit portal to a camp and mill below. The mine was inaccessible in 1950 (Ray, 1954). An average grade of 5 oz/ton Au was reported for the veins cross-cutting the dike (Capps, 1915). By 1933, the Talkeetna mine was undercut by, but not connected with, the workings of the Fern mine (ARDF number AN005). The same company, Fern Gold Mining Company, owned both the Talkeetna mine and Fern mine by about 1925. A surface grab sample of the vein walls, collected by the U.S. Bureau of Mines, contained 0.57 g/ton Au (0.017 oz/ton Au) (Kurtak, 1986). |
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| Indication of production | Yes; small |
| Production notes | Unknown, mining (and some milling) was reported from 1917-1923. |
| MRDS Number | A011620 |
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References | |
| Reporters | D.P. Bickerstaff (USGS contractor); S.W. Huss (USGS) |
| Last report date | 7/30/1998 |