Duke Island Ultramafic Complex

The Duke Island Ultramafic Complex is a iron 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: Duke Island Ultramafic Complex
Secondary: Ditto ? Prospect

Commodity

Primary: Iron
Secondary: Chromium
Tertiary: Platinum
Tertiary: Nickel
Tertiary: 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: Occurrence
Operation Type: Unknown
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

Not available

Mineral Deposit Model

Not available

Orebody

Not available

Structure

Not available

Alterations

Not available

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Chromite
Gangue: Pyrrhotite
Gangue: Pyrite
Unknown: Chalcopyrite
Unknown: Pentlandite

Comments

Comment (Commodity): ANALYSIS OF 22 SAMPLES: AVE. CONCENTRATIONS OF 0.037 PPM PT IN 10 SAMPLES, 0.033 PPM PD IN 16 SAMPLES, 0.010 PPM RH IN 6 SAMPLES, AND NO IR, USGS PP 800-C, P. C159

Comment (Location): PROSPECT IN AREA OF WIDESPREAD IRON MINERALIZATION IN LARGE ULTRAMAFIC COMPLEX, USGS OFR 78-73B, LOCS. 159-174; SEPARATE ENTRIES FOR EACH LOCATION LAND STATUS VALUE CALCULATED 6-94 USING GIS OVERLAY ANALYSIS WITH BLM 1:2,500,000 SCALE OWNERSHIP STATUS MAP (1991).

Comment (Development): DIAMOND DRILLED BY PRIVATE MINING INTERESTS; DETAILED GEOLOGICAL , GEOPHYSICAL AND GEOCHEMICAL WORK HAS BEEN DONE

Comment (Workings): DRILLED BY PRIVATE INTERESTS; NO EXTENSIVE DEVELOPMENT

Comment (Reserve-Resource): "AT LEAST ONE POTENTIALLY SIGNIFICANT DEPOSIT OF TITANIFEROUS MAGNETITE OCCURS IN THE PYROXENITE ZONE OF THE DUKE ISLAND ULTRAMAFIC COMPLEX," USGS OFR 78-73M, P. 27

Comment (Geology): HORNBLENDE PYROXENITE FORMS PARTIAL TO COMPLETE ENVELOPES AROUND UM BODIES COMPOSED OF GRADED LAYERS OF OLIVINE PYROXENITE AND DUNITE INTRUDED INTO LARGE MASS OF GABBRO; GRADED LAYERING OF PYROXENE AND TITANIFEROUS MAGNETITE OCCURS LOCALLY IN HORNBLENDE PYROXENITE; GABBRO IS ALTERED TO HORNBLENDE GABBRO NEAR CONTACTS WITH ULTRAMAFIC MASSES; LARGER BODIES ARE CONCENTRICALLY ZONED FROM DUNITE CORE TO PYROXENITE RIM

Comment (Deposit): DATA APPLIES TO DEPOSIT NOS. PR-159 THROUGH PR-174; NUMEROUS PROSPECTS ABOUT WHICH LITTLE IS KNOWN OTHER THAN COMMODITY (FE OR CR) AND LOCATION; IT IS ASSUMED THAT THEY ARE RELATED TO THE ULTRAMAFIC BODIES THAT ARE KNOWN TO OCCUR ON DUKE ISLAND ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT

Comment (Deposit): TITANIFEROUS MAGNETITE DISSEMINATED IN RHYTHMICALLY LAYERED HORNBLENDE PYROXENITE; RARE SPECKS OF PYRRHOTITE, PYRITE, PENTLANDITE AND CHALCOPYRITE WIDELY DISSEMINATED IN HORNBLENDE PYROXENITE; CHROMITE OCCURS IN DUNITE AND PERIDOTITE AS DISSEMINATED EUHEDRA AND GRAINS AND AS SMALL MASSIVE VEINS AND CLOTS

References

Reference (Deposit): USGS OFR 78-73B, LOC. 166

Reference (Deposit): IRVINE, T.N., 1959, THE ULTRAMAFIC COMPLEX AND RELATED ROCKS OF DUKE ISLAND, SOUTHEASTERN ALASKA: CALIFORNIA INSTITUTE OF TECHNOLOGY, PASADENA, PH.D. THESIS

Reference (Deposit): TAYLOR, H.P. AND NOBLE, J.A., 1960, ORIGIN OF THE ULTRAMAFIC COMPLEXES IN SOUTHEASTERN ALASKA: INTERNAT. GEOL. CONG., 21ST, COPENHAGEN, REPT., PT. 13, P. 178-180

Reference (Deposit): USGS OFR 78-73M, P. 24-25, 27

Reference (Deposit): USGS PP 800-C, P. C159

Reference (Deposit): USGS BULL 1246, P. 183

Reference (Other Database): BAG-OFR-78-73B-166

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