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Mapping by Larry Hulbert of the Geological Survey of Canada shows that the Dunite Hill mafic-ultramafic intrusive complex is one of the largest in the entire Nikolai (Alaska) and Kluane (Yukon) belt.
The mapping, combined with geophysical and geochemical surveys, has produced a model for the occurrence of Norilsk-style mineralization in the Dunite Hill area. Similarities between the massive Norilsk nickel/copper/platinum-group-element deposit in Russia and the Dunite Hill complex include mineralogy, geochemistry and tectonomagmatic setting.
Chemical studies of the Dunite Hill intrusive body and the overlying basalt flows indicate a significant depletion in nickel, copper and platinum group elements. Soil geochemical sampling (mobile metal ion) has shown strong nickel and palladium anomalies in overlying glacial tills covering the margins of the intrusion. This seems to point to near-surface sulphide mineralization in the basal portions of the intrusive complex.
Geophysical modeling of an airborne magnetic survey suggests that the Dunite Hill intrusive body is bowl-shaped with a strongly magnetic basal unit. Regional geophysical studies by the U.S. Geological Survey and the U.S. Bureau of Land Management have outlined a conductive zone in the core of the Dunite Hill complex. This zone has coincident high gravity and magnetics, and a strike length of about 10 km.
The conductor exists at a depth of 3.5 km in the west but rises to within 1 km of surface to the east, continuing towards surface around the margin of the bowl-shaped intrusion.
Nevada Pacific intends to perform a grid-based geophysical survey covering an 8-by-4-km area to define drill targets. Surveys will include induced-polarization to detect disseminated sulphide mineralization and gravity to detect massive sulphides. These data will be combined with existing geophysical data to define drill targets for the 2003 season.
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