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Flat River-Howards Pass

Flat River-Howards Pass

Broad mountain valley, right side forested, cloudy blue sky, townsite with curving dirt roads in valley.

Description

The geology of the Flat River - Howards Pass area in the Selwyn Mountains (western NWT) is poorly understood, even though it's rich in minerals and contains the Cantung tungsten mine and the world-class Howards Pass zinc-lead district. A number of research projects lead by NTGS staff and graduate students are examining questions about the structure and stratigraphy of the rocks to determine controls on where the rocks are mineralized.

Split face of NQ drill core showing intensely folded then faulted grey, dark grey, and yellow-grey laminations

Location

The area of interest lies against the western border of the NWT, in the Selwyn Mountains, from the Howard’s Pass district in the north (at about 62.5°N) to the Flat River - Cantung district in the south (at about 61.8°N), encompassing parts of the Flat River and Little Nahanni River valleys.

Two geologists looking at rock face showing cm-thick brown and grey layers in cm's amplitude chevron folds

Justification

Although only lightly explored, the area is known to host significant reserves of mineral commodities. The Cantung mine produces tungsten and copper with minor amounts of bismuth. The Howard’s Pass district in the north contains at least 15 deposits of zinc-lead, some of which are being assessed for development.  Other commodities of economic interest that have been discovered in the area include: zinc, lead, copper, silver, tungsten, gold, vanadium, rare earths, barite, and gems. The layered sedimentary rocks that host the major deposits have been folded and cut by faults, some of which are thought to have been involved in the mineralization processes.  A better understanding of the geology will allow the exploration industry to focus its efforts better.

 Geologist (female), bush gear (pack on back, dirty pants, gloves), pocket computer & stylus in hand, sunny day, rolling hills

Approach

A number of projects led by NTGS staff and graduate students under the supervision of professors are tackling discrete questions about the structure, mineralization, and stratigraphy of the district. Students are studying controls on placement of high-grade ore at Cantung, geological deformation as it relates to mineralization in the Cantung area, regional structures that are potentially related to ore-bearing fluids throughout the district, and the chemistry of stream sediments. Upcoming projects may include a study of the biostratigraphy of the host rocks of the Howards Pass deposits.

Dudes in an open pit, bit of blue sky, benches of rock are reddish grey, yellowish grey and grey, small drill rig midground right

Schedule

The first projects began with field work at and around Cantung in the spring and summer of 2015. Initial reports on this work are anticipated in the winter of 2015-16. A second field season is expected for some of the research projects with final reports in 2017.

From the air, over half is grey-clouded sky, barren rocky hill foreground right, flat white/grey glacier surface foreground, sharp brown peaks beyond

Partners and Support

NTGS Participants: Hendrik Falck, Edith Martel, Beth Fischer
Partners:
Dr. Lori Kennedy, University of British Columbia
Dr. Ken Hickey, University of British Columbia
Dr. Jacob Hanley, Saint Mary’s University
Dr. Michael Melchin, St. Francis Xavier University
Selwyn-Chihong Mining Ltd.
North American Tungsten Corporation Ltd.

Keywords

Selwyn Mountains, structure, March Fault, Howards Pass, Cantung, SEDEX, skarn, sediment-hosted, zinc, lead, tungsten, gold, ore fluid, fluid inclusions, structures, shear zone, fold, ore controls, structural controls, mineralization, biostratigraphy, conodont, graptolite, stratigraphy,  Lower Paleozoic, Proterozoic, Sekwi Formation, Rabbitkettle Formation, Duo Lake Formation, stream sediment, geochemistry