NORTHWEST TERRITORIES GEOSCIENCE OFFICE DISCOVERS PROMISING NEW MINERAL PROSPECT IN THE MACKENZIE MOUNTAINS

Yellowknife, NWT (November 16, 2009) – The Northwest Territories Geoscience Office (NTGO) announced today the discovery of a significant new zinc-lead-copper prospect in the Mackenzie Mountains, Northwest Territories. The prospect, named “Dap” by the geologists who found it, was discovered last summer during ground follow-up of a regional stream-silt geochemical survey. Click here to read the Information Notice. The Dap showing is located at 64° 48.9’ North and 131° 23.2’ West, in National Topographic System mapsheet 106B/14-SW, about 220 km west-southwest of Norman Wells (Figure 1).

The Dap prospect consists of disseminated to massive sphalerite, galena, chalcopyrite, bornite, and malachite concentrated along a stratigraphic contact. The showing is hosted mainly within heavily altered dolostone of the Lower Cambrian Sekwi Formation, but locally extends into brecciated siltstone of the overlying, Middle Cambrian Hess River Formation. The ore minerals are void-filling, and occur in variable concentrations and proportions along a minimum 400 m strike length. Galena locally forms massive pods up to 30 cm in length, in clusters of several pods. Initial assay results from random grab samples include: 3.3% Zn and 0.12% Pb; 1.2% Zn and 0.25% Pb; 0.9% Cu; and 0.43% Zn and 0.03% Cu. The Dap showing is unusual for carbonate-hosted Zn-Pb showings in the Mackenzie Mountains region because of its significant copper content and higher-than-usual proportion of lead.

Regionally, the new discovery sits along a major NW-trending fault zone which is associated with other Zn-Pb showings and Zn-U±Pb±Cd±Co±Ag silt anomalies along 130 km of strike-length (Figure 1; note that silt geochemical data are not yet available for the Sahtu Settlement Area part of this map). These associations suggest that the fault zone is an important control on mineralization. Thirty kilometres SE of Dap along the same fault zone, two anomalous stream silt samples and a single gold grain from a heavy mineral concentrate of stream sediments were collected from a drainage basin. A sudden storm curtailed investigation of this watershed (labelled F1 on Figure 1), however a grab sample of Canol Formation shale contained 954 ppm Zn and mildly anomalous Cu, Ni, V, Th, U, and Co. Exposed strata in the complexly faulted watershed include carbonate and siliciclastic rocks ranging from Proterozoic to Middle Devonian in age.

Permeable carbonate strata of any age along the regional fault zone are considered highly prospective for deposits of this type, especially where capped by impermeable shales or siltstones and associated with a stream silt anomaly. Most of the previously known groups of showings in the region were discovered because of associated gossans, however it is noteworthy that the Dap showing does not have any strong visual expression. Careful prospecting of areas selected on the basis of the above criteria will therefore be essential to discovery. The stream geochemical survey results which led to the discovery of the Dap showing are available as NWT Open Report 2008-013, downloadable here. Results of a stream geochemical survey covering the eastern part of the prospective fault will be published as an NWT Open Report later this year.

The Dap showing is covered by a Prospecting Permit, however the F1 watershed is on open ground. The entire western part of the prospective fault zone, including Dap and F1, is within the Tsiigehtshik Gwit’lit Special Management Zone of the Gwich’in Settlement Area. The Gwich'in Land Use Plan defines Special Management Zones as those “where all land uses are possible as long as conditions outlined in the Land Use Plan are met and approvals through the regulatory system are obtained.” More information may be obtained at http://gwichinplanning.nt.ca/landUsePlan.html.