| Main commodities | Ag; Pb; Sn; Zn |
|---|---|
| Other commodities | As |
| Ore minerals | arsenopyrite; cassiterite |
| Gangue minerals | pyrite; quartz; sericite; tourmaline |
| Quadrangle map, 1:250,000-scale | LC |
|---|---|
| Quadrangle map, 1:63,360-scale | B-6 |
| Latitude | 60.4007 |
| Longitude | -154.9423 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | The Kody West prospect is located in the Koksetna Hills approximately 20 miles northwest of Lake Clark. The prospect is on the hill southeast of hill 3017 at the headwaters of a tributary of the Koksetna River. Along the section line of the southwest 1/4 of section 25 and the northwest 1/4 of section 36 in T. 4 N., R. 33 W. of the Seward Meridian is the approximate center of the 1/2 kilometer prospect area. |
Geologic descriptionThe area between the Koksetna and Chilikadrotna Rivers is underlain by undivided Kuskokwim Group sedimentary rocks and the Koksetna River sequence of Wallace and others (1989) that have been intruded by Cretaceous to Tertiary quartz monzonite plutons and rhyolite to dacite plugs, sills, dikes and flows (Wilson and others, 2006). The Kody West prospect lies within the Koksetna River sequence.
Hornfelsed greywacke float over a 500 by 400 meter area was found to contain abundant 0.5 to 5 centimeter wide quartz and iron oxide veins with one sample containing visible cassiterite mineralization (Scott and Ellis, 1982). The veins commonly contain gossan in void spaces and are associated with intense quartz-sericite alteration of the wall rocks with local traces of tourmaline. These veins are anomalously high in lead, zinc, silver, arsenic and tin (Ellis and others, 1985). The observed veining and an aeromagnetic anomaly at Kody West indicate the likely presence of a shallow buried intrusive which could be related to the nearby (3 kilometers east-southeast) Kody (LC055) Sn-porphyry system (Ellis and others, 1985). | |
| Geologic map unit | (, ) |
|---|---|
| Mineral deposit model | Sn-Polymetallic veins (Cox and Singer, 1986; model 20b). |
| Mineral deposit model number | 20b |
| Age of mineralization | Mineralization is probably related to 60.5 to 61.6 Ma intrusions dated in the Koksetna Hills (Eakins and others, 1978). |
| Alteration of deposit | Abundant limonite stained quartz veins are seen cutting hornfelsed greywacke. The veins are associated with intense quartz-sericite alteration of the wall rocks with local traces of tourmaline (Ellis and others, 1985). |
| Workings or exploration |
Anaconda Minerals Company (Anaconda) discovered the Kody West prospect in 1982 while following up on aeromagnetic and color anomalies. Mapping and grid rock sampling were completed. Grab samples from Kody West veins were anomalous in silver (2.3 parts per million (ppm) to 28.5 ounces per ton), lead (339 ppm to 8.55 percent), and zinc (710 to 2160 ppm). Several samples were also anomalous in arsenic, and two samples had tin values of 1150 and 3070 ppm (Scott and Ellis, 1982). In 1983 Anaconda completed a ground magnetic survey and grid rock sampling of vein material. The quartz veins with gossan in void spaces were anomalously high in lead (100 ppm to 8.55 percent), zinc (300 to 3300 ppm), silver (1 to 912 ppm), arsenic (100 to over 1000 ppm), and tin (50 to 3070 ppm). The 21 line kilometer magnetic survey detected a shallow (less than 250 meter) 600 gamma anomaly under the topographic peaks at Kody West (Ellis and others, 1985). |
|---|---|
| Indication of production | None |
References | |
| Reporters | W.T. Ellis (Alaska Earth Sciences) |
|---|---|
| Last report date | 3/15/2016 |