| Main commodities | Ag; Au; Cu; Pb; Zn |
|---|---|
| Other commodities | As; Sb |
| Ore minerals | arsenopyrite; berthierite (fesb2s4); chalcopyrite; galena; pyrite; sphalerite |
| Gangue minerals | calcite; quartz |
| Quadrangle map, 1:250,000-scale | PE |
|---|---|
| Quadrangle map, 1:63,360-scale | A-6 |
| Latitude | 56.1097 |
| Longitude | -133.9587 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | The veins at this occurrence are exposed on a bedrock bench on the intertidal zone about 2.0 mile north of Point St. Albans. The deposit is about 350 yards southwest of triangulation station 'June' shown on the current (1968) 1:63,360 topographic map, near the northeast corner of section 33, T. 66 S., R. 74 E. The location is accurate. |
Geologic descriptionThe veins here were first noted by Houston and others (1958) in their work on the uranium resources of Alaska; they provide little information other than they contain less than 0.0001 equivalent uranium and sphalerite. A claim was staked on the deposits in 1954 but Still and others note that as of 2002, there are no claims on the deposit. This description of the occurrence is largely based on field work in the early 1980s during a mineral resource assessment of the Petersburg quadrangle (Grybeck and others, 1984) and later work by Still and others (2002), all of whom examined the deposit as part of government programs. Several quartz-calcite veins and lenses up to 6 feet thick and up to a hundred feet long are exposed in rocks exposed in the intertidal zone; they contain abundant sphalerite, galena, pyrite, arsenopyrite, and berthierite (FeSb2S4) (Grybeck, Berg, and Karl, 1984). The veins cut the periphery of a Cretaceous hornblende diorite pluton, which intrudes turbidites of the Silurian Bay of Pillars Formation (Brew, and others, 1984). Selected samples of the veins contain up to 0.5 parts per million (ppm) gold, 300 ppm silver, 360 ppm copper, about 2 percent lead, and 14 percent zinc. As described by Still and others (2002), the quartz-calcite veins are widely spaced and contain spotty, high-grade mineralization across narrow widths. The highest gold values were 8,767 and 5,839 parts per billion; four of the samples contained high silver values of from 126 to 342 ppm. Their samples also contained up to 9.9 percent, zinc, up to 8.15 percent lead, and high contents of mercury, arsenic, and antimony. A sample of massive pyrrhotite and pyrite with interstitial quartz contained 3,094 ppm copper. | |
| Geologic map unit | (-133.960438837401, 56.1093200114495) |
|---|---|
| Mineral deposit model | Polymetallic vein (Cox and Singer, 1986; model 22c). |
| Mineral deposit model number | 22c |
| Age of mineralization | Veins cut Cretaceous hornblende diorite. |
| Alteration of deposit | None or minor. |
| Workings or exploration | First noted by Houston and others (1958, p. 24) in their work on the uranium resources of Alaska; they provide little information about the veins other than they contain less than 0.0001 equivalent uranium and sphalerite. A claim had been staked on the deposits in 1954 but Still and others note that as of 2002, there are no claims on the deposit. The description of this site is largely based on field work in the early 1980s during a mineral resource assessment of the Petersburg quadrangle (Grybeck, Karl, and Berg, 1984) and later work by Still and others (2002), all of whom examined the deposit as part of government programs. |
|---|---|
| Indication of production | None |
| Reserve estimates | None. |
| MRDS Number | A010325 |
|---|---|
ReferencesStill, J.C., Bittenbender, P.E., Bean, K.W., and Gensler, E.G., 2002, Mineral assessment of the Stikine area, central southeast Alaska: Bureau of Land Management Technical Report 51, 560 p.
U.S. Bureau of Mines, 1980, Claim map, Petersburg quadrangle, Alaska: U.S. Bureau of Mines Map 117, 1 sheet, scale 1:250,000.
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| Reporters | H. C. Berg (Fullerton, California); D.J. Grybeck (Port Ludlow, WA) |
| Last report date | 3/4/2008 |