The Howard’s Pass lead-zinc deposits, which resemble the producing Red Dog deposits of Alaska, are hosted in Ordovician-Silurian Selwyn Basin shale, and the Tom and Jason deposits are hosted in Devonian Earn Group shale. Project objectives are to improve understanding of the architecture and evolution of both basins in order to derive new vectors to shale-hosted base metal mineralization. The geographic emphasis for the project is NTS sheets 106B and 105I. During the upcoming field seasons we intend to conduct regional mapping, stratigraphic studies, and thematic projects to clarify the stratigraphy and structure of the Earn and Road River groups, to understand the relationship of mineralization to structure and depositional setting, and to document and delineate economically prospective formations.

Community information sessions were held by NTGO in early 2009 in Norman Wells, Inuvik, Fort McPherson and Tsiigehtchic, and in early 2010 in Norman Wells and Tulita.

THE PEOPLE

To date, participants have included workers from the Northwest Territories Geoscience Office, University of Alberta, Laurentian University, United State Geological Survey, Selwyn Resources, Eagle Plains Resources, Trans-Polar Geological Consulting, and the Geological Survey of Canada. A full-day workshop held in Vancouver in January 2010 fostered new partnerships with industry and collaboration with universities, including Carleton University and Simon Fraser University.

2009 RECONNAISSANCE

The first field season consisted of six weeks of reconnaissance in 106B and mapping in 105I.

• Following-up on the results of a 2007 NTGO stream silt geochemical survey in 106B, we identified three spatial associations: 1) Au anomalies with Marmot Formation volcanic rocks, 2) Zn anomalies with both Cambrian to Devonian carbonate rocks and a prominent regional fault, and 3) Cu-U anomalies with rocks of the Road River and Earn groups. The specific sources of most of the anomalies remain undiscovered, however, a significant new base metal prospect, here named the Dap showing, was found associated with a Zn-Pb silt anomaly. Disseminated to massive sphalerite and galena, with minor copper sulphides, are associated with a regional fault and stratigraphic contact between the Sekwi and Hess River formations. The mineralization is hosted mainly within heavily altered Sekwi Formation and remains open in all directions. Mineralization is persistent along 400m strike-length and for 2-7m down-dip along the contact. This showing has no associated gossan or other surface expression which would otherwise have revealed it.

• Theses research projects were initiated:

  • B.Sc.: Nature of bioturbations in the Steel Formation at Howard’s Pass, NWT.

  • M.Sc.: Barite as a possible vector to SEDEX mineralization in Selwyn Basin and Misty Creek Embayment, NWT.

  • Ph.D.: Geochemistry and regional stratigraphy of the Rapitan iron formation in Mackenzie Mountains, NWT.

• Three weeks of mapping at Howard’s Pass revealed clear evidence of bedding transposition and suggests a high degree of complication by imbricate thrusting. The highly deformed state of the host, underlying, and overlying rocks was not fully appreciated in the past, and many tectonic fabrics have previously been described as sedimentary. The presence of regional-scale detachments encompassing the deposit suggest that it is situated in a duplex structure. Further mapping and structural analysis is essential to effectively predict sub-surface deposit locations where the mineralized trend extends into the NWT.

• Thematic studies at Howard’s Pass conducted by Hendrik Falck and USGS collaborators Karen Kelley and John Slack focused on characterizing the geochemical signature and geochronology of the host rocks and mineralization, in order to draw similarities and differences between the well-document Red Dog Deposits in Alaska and the Howard’s Pass district.

Click here to download a detailed project brochure:

2010 Project Brochure
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2010 FIELD SEASON

During the summer of 2010, field work for four graduate theses will be conducted (ongoing and newly initiated).

Continued mapping and thematic studies at Howard’s Pass, in collaboration with Selwyn Resources Ltd, may be conducted around the CMC area in the Northwest Territories.

UPCOMING FIELD SEASONS

Future field seasons will include regional mapping, stratigraphic studies, and thematic projects for release as NWT Open Files and graduate theses. Sample analyses will provide better biostratigraphic and geochronological control and elucidate differences in depositional and diagenetic environments, including the unusually carbonaceous nature of the host Duo Lake (Howard’s Pass) Formation at Howard’s Pass. This work will clarify our understanding of the relationship of mineralization to structure and depositional setting, and delineate economically prospective formations.

REFERENCES

Cecile, M.P., 1982. The Lower Paleozoic Misty Creek Embayment, Selwyn basin, Yukon and Northwest Territories; Geological Survey of Canada, Bulletin 335, 78 p.

Gordey, S.P. 2008. Geology, Selwyn Basin (105J and 105K), Yukon. Geological Survey of Canada, Open File 5438, scale 1 : 250 000.

Gordey, S.P. and Anderson, R.G., 1993. Evolution of the northern Cordilleran miogeocline, Nahanni map area (105I), Yukon and Northwest Territories; Geological Survey of Canada, Memoir 428, 214 p.

Gordey, S.P., Roots, C.F., Martel, E., MacDonald, J., Fallas, K., MacNaughton, R., Leslie, C., and Fischer, B., 2009. Preliminary bedrock geology, Mount Eduni, Northwest Territories; Geological Survey of Canada, Open File 5984; Northwest Territories Geoscience Office, NWT Open Report 2008-014. 1 map, scale 1:125 000.

Martel, E., Fischer, and Falck, H. 2009. Selwyn-Mackenzie Shale Basins Project, is another red Dog hiding in the Misty Creek Embayment?. Program of Talks and Abstracts, 37th Yellowknife Geoscience Forum, Yellowknife, NT. Roots, C., and Martel, E., 2008. Provisional bedrock geology of Sekwi Mountain map area (NTS 105P and parts of 106A, 95M and 96D), Mackenzie Mountains, Northwest Territories; Northwest Territories Geoscience Office, NWT Open File 2008-04.