Mary T.

The Mary T. is a gold mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Mary T.

Commodity

Primary: Gold
Secondary: Copper

Location

State: Alaska
District: Ketchikan

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Model Name: Distal disseminated Ag-Au

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: The hostrocks are pyritized, and the chalcopyrite locally is oxidized to malachite and azurite.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Chalcopyrite
Ore: Gold
Ore: Pyrite
Gangue: Quartz

Comments

Comment (Reference): Primary Reference = Wright and Wright, 1908; Maas and others, 1995

Comment (Workings): Workings / Exploration = Workings dating to the early 1900s include a flooded, 9-foot-deep shaft, a trench, and two pits. The owners at that time reported assays of up to 15% Cu and $11 in gold/ton (Au at $20.67/oz.). The average metal contents of U.S. Bureau of Mines (Maas, 1995) samples of the Mary T. deposit are: 0.95 ppm Au, 2.89 ppm Ag, 2698 ppm Cu, 7.0 ppm Pb, and 117 ppm Zn.

Comment (Deposit): Model Name = Distal disseminated Ag-Au? (Bliss, 1992; model 19c)

Comment (Geology): Geologic Description = The country rocks near this site include gray and green phyllite and semischist derived from intertonguing flysch and andesitic and basaltic volcanic rocks (Berg and others, 1988, p. 17-20); and gray felsic schist possibly derived from silicic tuff (Maas and others, 1995, p. 183 and fig. 46). Near Smugglers Cove, the bedded rocks are intruded by diorite that may be transitional to the andesitic and basaltic volcanic rocks. The bedded and intrusive rocks were regionally metamorphosed to greenschist grade in Late Cretaceous time (Brew, 1996, p. 27). Their premetamorphic age is uncertain. Berg and others (1988, p. 17) note that the intertonguing flysch and volcanic rocks closely resemble Upper Jurassic to mid-Cretaceous marine strata nearby on Gravina Island.? the deposit consists of sericite or chlorite schist containing quartz blebs and abundant disseminated cubes of pyrite, minor chalcopyrite, and small amounts of gold (Wright and Wright, 1908, p. 157). The chalcopyrite locally is oxidized to malachite and azurite. Maas and others (1995, p. 184 and tables 45 and 46) suggest that the Mary T. prospect may be part of a belt of exhalative volcanogenic gold deposits (KC035) that extends along the northeast shore of Smugglers Cove and also includes the U.S. (KC037) and Blue Bucket (KC039) deposits. The average metal contents of their samples of the Mary T. deposit are: 0.95 ppm Au, 2.89 ppm Ag, 2698 ppm Cu, 7.0 ppm Pb, and 117 ppm Zn. Workings dating to the early 1900s include a flooded, 9-foot-deep shaft, a trench, and two pits. The owners at that time reported assays of up to 15% Cu and $11 in gold/ton (Au at $20.67/oz.).

References

Reference (Deposit): Brew, D.A., 1996, Geologic map of the Craig, Dixon Entrance, and parts of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2319, 53 p., 1 sheet, scale 1:250,000.

Reference (Deposit): Wright, F.E., and Wright, C.W., 1908, The Ketchikan and Wrangell mining districts, Alaska: U.S. Geological Survey Bulletin 347, 210 p.

Reference (Deposit): Elliott, R.L., Berg, H.C., and Karl, Susan, 1978, map and table describing metalliferous and selected nonmetalliferous mineral deposits, Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-file Report, 78-73-B,17 p., scale 1:250,000.

Reference (Deposit): Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map MF-1807,27 p., scale 1:250,000.

Reference (Deposit): Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.

Reference (Deposit): Brooks, A.H., 1902, Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska: U.S. Geological Survey Professional Paper 1, 120 p.

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