previously thought, with the recognition that large areas of VMS associated stratigraphy
previously mapped as part of the Late Devonian-Early Mississippian Sicker Group are
actually part of a previously unrecognized cycle of bimodal arc volcanism of
Pennsylvanian through Early Permian age. This newly recognized component of the
PWA has geochemical and isotopic characteristics suggesting derivation from hotter and
more primitive melts than its Sicker Group counterpart. In addition, Late Paleozoic,
VMS associated, bimodal volcanic rocks are conformably overlain by limestones,
suggesting formation in a shallow water environment. Collectively, these characteristics
suggest that underexplored, Late Paleozoic volcanic rocks of the PWA may be
prospective for precious metal enriched VMS deposits, similar to that of the famous
Eskay Creek, LaRonde Penna, and Horne Mines.
This field trip will highlight a newly revised model for the tectonic and metallogenic
evolution of the PWA, with emphasis on characterizing the timing and geological setting
of its contained VMS mineralization. The trip will also provide an introduction to how a
combination of geological mapping, geochronological, lithogeochemical and isotopic
studies can be applied to elucidate the most prospective components of a terrane for
hosting VMS mineralization. The field trip will culminate with an underground tour of
the world class Myra Falls VMS deposit (Nyrstar N.V.).
Support for research by Ruks et al. has been generously provided by Geoscience BC,
Bitterroot Resources Ltd., Paget Resources Corporation, Treasury Metals Inc., Westridge
Resources Inc., Nyrstar N.V., a Natural Sciences and Engineering Research Council of
Canada (NSERC) Discovery Grant to Jim Mortensen, and an NSERC postgraduate
scholarship to Tyler Ruks.
DETAILED ITINERARY:
Saturday, Sept. 21
st
(travel from Vancouver to Vancouver Island; Cowichan area
stratigraphy and VMS mineralization)
The group will meet at Horseshoe Bay ferry terminal (West Vancouver) at 5:45 a.m. at
the latest, in time for 6:20 a.m. sailing to Nanaimo. The group will arrive at the forestry
gate on McMillan Bloedel Forest Service road at 8:30 a.m., where an overview of PWA
tectonic evolution and metallogeny will commence. Field stops will begin by examining
outcropping VMS mineralization and host strata exposed on Big Sicker Mountain,
including the past producing Lenora deposit. Final stops for the day will include a visit to
the Lara VMS deposit (Treasury Metals Inc.) and the nearby, Lady B iron formation. The
group will leave the area around 3 p.m., arriving in Port Alberni around 6 p.m. that
evening.
Accommodations for the evening:
Redford Hotel, 3723 Redford St., Port Alberni, BC; (250) 724-0121