| Main commodities | Ag; Au; Cu; Pb; Zn |
|---|---|
| Ore minerals | chalcopyrite; pyrite; sphalerite |
| Gangue minerals | quartz |
| Quadrangle map, 1:250,000-scale | CR |
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| Quadrangle map, 1:63,360-scale | B-2 |
| Latitude | 55.26567 |
| Longitude | -132.66673 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | This prospect is near the shoreline of upper Hetta Inlet about 0.4 mile west of Dell Island. It is in the NE1/4 section 20, T. 76 S., R. 84 E. Informally, it is sometimes called the 'Deer Island exhalite' (e.g., Hedderly-Smith, 1999 [Inventory]), although it is about 2 miles north of the mouth of Deer Bay and there is no nearby Deer Island on the USGS topographic maps. The mineralization is exposed along a logging road parallel to the shoreline at an elevation of about 100 feet. |
Geologic descriptionThis prospect was identified as a massive sulfide deposit by Sealaska geologists in 1988, and mapped and sampled by the American Copper and Nickel Company in 1991 and 1993 (Maas and others, 1995; Hedderly-Smith, 1999 [Inventory]). There is a short adit near the shoreline that indicates earlier work not described in the literature. The rocks in the vicinity consist of quartz-sericite-chlorite schist and metabasalt of the Wales Group of Late Proterozoic and Cambrian age that are cut by rhyodacite porphyry and diabase dikes and sills (Herreid and others, 1978; Maas and others, 1995; Hedderly-Smith, 1999 [Inventory]). The metamorphic rocks strike northeast and dip northwest. The deposit consists of a stratabound, exhalite zone up to 35 feet thick with pyrite, chalcopyrite, and sphalerite; the zone can be traced for about 1,100 feet along strike. The average value of a set of samples across the zone was 2,345 parts per million (ppm) copper, 2,263 ppm zinc, 5.7 ppm silver, and 309 parts per billion gold (Hedderly-Smith, 1999 [Inventory]). | |
| Geologic map unit | (-132.668382985535, 55.2653185604048) |
|---|---|
| Mineral deposit model | Kuroko massive sulfide (Cox and Singer, 1986; model 28a). |
| Mineral deposit model number | 28a |
| Workings or exploration | Sampling of mineralization in outcrops along a logging road in the late 1990s, as well as geologic mapping and geochemical sampling. A short adit nearby was probably driven in the early 1900s. |
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| Indication of production | None |
Additional commentsThis prospect is on land that has been conveyed to the Sealaska Corporation or is under application for transfer to them. | |
ReferencesHedderly-Smith, D.A., 1989, Report of the 1988 field season - Sealaska Mineral Reconnaissance Project: Sealaska Corporation, 66 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1990, Report of the 1989 field season - Sealaska Mineral Reconnaissance Project: Sealaska Corporation, 58 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1991, Report of the 1990 field season-Sealaska Mineral Reconnaissance Project: Sealaska Corporation: Sealaska Corporation, 2 vols., 180 p., 13 plates. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1992, Report of the 1991 field season - Sealaska Mineral Reconnaissance Project: Sealaska Corporation, 2 vols., 225 p. 23 plates. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1999, Inventory of metallic mineral prospects, showings and anomalies on Sealaska lands, 1988 through 1998: Sealaska Corporation, Juneau, Alaska, 217 p. (internal report held by Sealaska Corporation, Juneau, Alaska).
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| Reporters | D.J. Grybeck (Applied Geology) |
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| Last report date | 5/1/2004 |