Ni–Cu–PGE Deposits in the Cape
Smith Belt
Abdelali Moukhsil and Serge Perreault
Géologie Québec
EXPLORATION FOR Ni, Cu AND PGEs
Over the years, several showings of Ni–Cu
mineralization have been discovered in the Cape Smith Belt (Ungava
Trough). The earliest work that mentions such occurrences dates
back to the end of the 19th century. The first copper–nickel
showings in the Cape Smith–Wakeham Bay area were discovered
by Murray Watts in 1937. These showings were developed by various
companies in subsequent decades.
The Cape Smith Belt has unique mineral potential
that is still largely undeveloped in Québec. During the 1950s,
several companies became interested in this area, in conjunction
with geological mapping undertaken by the gouvernement du Québec.
Numerous showings and deposits were discovered at the time, including
the Delta and Expo-Ungava deposits, as well as most of the Raglan
mining camp deposits (Figure 1).
Toward the mid-1980s, the belt was confirmed as a target area for
platinum exploration.
In 1997, High North Resources,
under Ungava Minerals Corporation's option, carried
out a drilling program (1,038 m), mapping and airborne/ground-based
geophysical surveys on the Expo-Ungava property. The program revealed
that the Expo-Ungava deposit was formed of massive sulfide lenses
at the base of ultramafic sills injected into the Povungnituk Group.
The geochemical signature of these ultramafic sills is similar to
ultramafic suites and cogenetic flows forming the Chukotat Group
(Picard et al. 1995, MB 94-30). The geological model suggests that
sulfides accumulated in troughs at the base of an ultramafic lava
flow or sill that opens towards the west. The trough is truncated
to the west by a thrust fault that juxtaposes sedimentary and volcanic
rocks. A number of remobilized massive sulfide lenses occur within
the sediment in the fault walls.
In 2001, Canadian Royalties Inc.,
under Ungava Minerals Corporation's option (Figure 1),
discovered significant amounts of platinum and palladium as a result
of new analyses of core samples taken during the 1997 drilling program
conducted by High North Resources. During the initial
program, drill cores were assayed for nickel, copper and cobalt
but not for the platinum group elements (platinum, palladium, and
rhodium). Other work carried out by the company in the summer of
2001 revealed mineralization along a length of 732 m in the east–west
axis, with an average width of 107 m along the north–south
axis.
During the same period, Canadian Royalties
Inc. discovered significant amounts of platinum, palladium,
nickel, and copper as the result of work done on a new showing (Phoenix),
located on the TK property, 20 km south of the Raglan mining camp
and 7 km northeast of Expo–Ungava. The mineralization comprises
massive sulfides near the base of an ultramafic sill (TK sill) similar
to the Raglan sill.
Prospects
The most recent results of the work carried out
by Canadian Royalties reveals an outstanding potential for PGEs
associated with ultramafic sills cogenetic to the Chukotat Group
that are injected into the Povungnituk Group. The Povungnituk is
currently one of the most promising sectors for mineral exploration
in Québec due to the significant quantities of lava flows
and mafic and ultramafic sills it contains. The task at hand is
to find sufficient volume to make mining of these elements economically
feasible. The prospects in this regard are excellent.
See also:
Geological
overview
Ni-Cu dominant
magmatic deposits
PGE dominant
magmatic deposits
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