Difficult Creek

The Difficult Creek is a zinc, copper, and 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: Difficult Creek

Commodity

Primary: Zinc
Primary: Copper
Primary: Gold

Location

State: Alaska
District: Reboubt

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

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

Physiography

Not available

Mineral Deposit Model

Model Name: Massive sulfide, kuroko

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: The Difficult Creek occurrence has alteration characteristics of a Kuroko type massive sulfide deposit that includes sulfate alteration, and silification.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Sphalerite
Ore: Pyrite
Ore: Gold
Ore: Chalcopyrite
Gangue: Quartz
Gangue: Calcite
Gangue: Barite
Gangue: Anhydrite

Comments

Comment (Geology): Age = Jurassic massive sulfide.

Comment (Exploration): Status = Inactive

Comment (Deposit): Model Name = Kuroko massive sulfide (Cox and Singer, 1986; model 28a)

Comment (Deposit): Other Comments = This occurrence is owned by Cook Region Native Association.

Comment (Geology): Geologic Description = The Difficult Creek occurrence is within the lower Jurassic Talkeetna Formation, an approximately 2,575 meter thick sequence of volcanic and volcaniclastic rocks (Determan and Hartsock, 1966). The volcanic section near the prospect is structurally bounded on the west by the Bruin Bay Fault, a major fault system traceable for over 500 kilometers. On the east, the volcanics are unconformably overlain by upper Jurassic marine sediments (Determan and Hartsock, 1965). The Talkeetna Formation is intruded by rocks of the Aleutian range -Talkeetna Mountain plutonic belt approximately 23 km southwest of the prospect. These intrusives which consist dominantly of coarse-grained quartz diorites and quartz monzonites have been dated between 175 and 145 m.y. ( Steefel, 1987). . At Difficult Creek, the Talkeetna Formation has been divided into three major groups (Steefel, 1987). The lowest group consist of purple and green andesite flows and breccia which locally show well-developed pillows. The middle group that host the mineralization, consists of coarse-grain felsic breccias, reworked volcaniclastic rocks, crystal tuffs, and dacite flows. The upper group consists of polymitic andesitic breccias and conglomerates with minor amounts of andesitic flows. . The mineralization consists of strataform massive sulfides layers and lens which contain pyrite, chalcopyrite and sphalerite. There are no published assay results for this occurrence. William Ellis (personal communication, 1999) speculates that this occurrence is a Kuroko type massive sulfide deposit.

Comment (Workings): Workings / Exploration = The occurrence was discovered by Anaconda Minerals in 1982 as part of a exploration program at the Johnson River prospect. To date there has been detailed mapping, stream and soil geochemical surveys, and surface trenching and sampling. No assay results are available.

References

Reference (Deposit): Detterman, R.L., Reed, B.L., and Lamphere, A.A., 1965, Jurassic plutonism in the Cook Inlet region, Alaska: U.S. Geological Survey Professional Paper 525-D, p. D16-D21.

Reference (Deposit): Detterman, R.L., and Hartsock, J.L., 1966, Geology of the Iniskin-Tuxedni region, Alaska: U.S. Geological Survey Professional Paper 512, 78 p.

Reference (Deposit): Steefel, C.I., 1987, The Johnson River Prospect, Alaska: Gold rich sea-floor mineralization from the Jurassic: Economic Geology, V. 82, p. 894-914.

Reference (Deposit): Swainbank, R.C., Bundtzen, T. K., Clough A.H., and Henning, M.W., 1997, Alaska's mineral industry 1996: Alaska Division of Geological and Geophysical Surveys Special Report 51, 68 p.

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