Quadrangle map, 1:250,000-scale | MH |
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Quadrangle map, 1:63,360-scale | B-5 |
Latitude | 63.3178 |
Longitude | -146.06 |
Nearby scientific data | Find additional scientific data near this location |
Location and accuracy | This prospect is at an elevation of 4,400 feet in the headwaters of an unnamed west fork of Specimen Creek, in the NW1/4NE1/4 section 32, T. 18 S., R. 9 E., Fairbanks Meridian. The occurrence corresponds to localities 51 and 52 in table 2 of Nokleberg and others (1991). |
Geologic descriptionThe rock at this occurrence consists of Upper Triassic olivine cumulate intruded by a metadiabase dike (Nokleberg and others, 1991). Rose (1965, figure 2) mapped a peridotite body in the headwaters of Specimen Gulch. The olivine cumulate contains disseminated chromite; sample 79CH010B assayed more than 5,000 parts per million chromium (Nokleberg and others, 1991). Malachite occurs along fractures in the metadiabase dike; grab sample 79CH010C of dike material contained 150 parts per billion gold. | |
Geologic map unit | (-146.062262919191, 63.3173803618724) |
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Mineral deposit model | Disseminated chromite in ultramafic rocks; epigenetic? shear zone mineralization. |
Age of mineralization | The chromite is Late Triassic, the presumed age of the ultramafic host rock. The copper and gold are Late Triassic or younger. |
Alteration of deposit | Oxidation of copper mineral(s). |
Workings or exploration | The occurrence is on active MAN Resources claims. |
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Indication of production | None |
References | |
Reporters | W.T. Ellis (Alaska Earth Science), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS) |
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Last report date | 6/19/2001 |