Stratigraphic and Paleotectonic Studies of the Middle Paleozoic Sicker Group and Contained VMS Occurrences, Vancouver Island, BC (NTS 92B, 92C, 92E, 92F)
- Jim Mortensen, University of British Columbia

Project Study Area The mid-Paleozoic Sicker Group forms the basement of Wrangellia Terrane on Vancouver Island. Volcanic strata of the Sicker Group are currently interpreted to represent an oceanic arc assemblage which is overlain by a variety of Upper Paleozoic sedimentary rock units. The arc sequence hosts the Myra Falls volcanogenic massive sulphide (VMS) deposit, which is currently the largest and most productive VMS mine in western Canada. VMS occurrences are known to occur elsewhere in the Sicker Group, especially in the Cowichan Lake Uplift (Mt. Sicker and Lara occurrences); however the setting of these occurrences is too poorly understood at present to permit detailed comparison with those of the Myra Falls deposit. The relatively poor overall understanding of the age and petrotectonic evolution of the Sicker Group makes it difficult to develop a sound strategy for regional VMS exploration within the sequence based on typical stratigraphic and volcanological criteria. This study will employ detailed geological mapping and sampling of key sections of the Sicker Group, especially in the Cowichan Lake Uplift, together with U-Pb zircon dating and petrochemical and isotopic studies of the volcanic rocks and associated intrusive and sediment strata as well as contained potential VMS occurrences. The main goal of the study is to develop a well constrained model for the evolution of the Sicker Group on Vancouver Island and compare and contrast the stratigraphic and tectonic setting of known VMS deposits and occurrences and assess the potential for other occurrences of this type.

Posters and Presentations
2010: New Results of Geological Mapping and Micropaleontological and Lead Isotopic Studies of Volcanogenic Massive Sulphide Hosting Stratigraphy of the Middle and Late Paleozoic Sicker and Lower Buttle Lake Groups on Vancouver Island, British Columbia (NTS 092B/13, 092C/16, 092E/09, /16 092F/02, /05, /07)
- Mineral Exploration Roundup Poster (pdf, 2.17MB)


2009: Stratigraphy of the Middle Paleozoic Sicker Group and Contained Volcanogenic Massive Sulphide (VMS) Occurrences, Vancouver Island, British Columbia
- Mineral Exploration Roundup Poster (pdf, 2.03MB)


2008: Geological Setting of Volcanogenic Massive Sulphide Occurrences in the Middle Paleozoic Sicker Group of the Cowichan Lake Uplift, Port Alberni Area (NTS 092F/02, /07), Southern Vancouver Island, British Columbia
- Mineral Exploration Roundup Poster (zip, 364MB)


2007: Geological Setting of Volcanogenic Massive Sulphide Occurrences in the Middle Paleozoic Sicker Group: Southeastern Cowichan Lake Uplift, Southern Vancouver Island, British Columbia
- Mineral Exploration Roundup Poster (pdf, 72.5MB)


2006: Stratigraphic and Paleotectonic Studies of the Middle Paleozoic Sicker Group and Contained VMS Occurrences, Vancouver Island, British Columbia
- Mineral Exploration Roundup Poster (pdf, 9.79MB)

Technical Articles
2010: "New Results of Geological Mapping and Micropaleontological and Lead Isotopic Studies of Volcanogenic Massive Sulphide--Hosting Stratigraphy of the Middle and Late Paleozoic Sicker and Buttle Lake Groups on Vancouver Island, British Columbia (NTS 092B/13, 092C/16, 092E/09, /16, 092F/02, /05, /07)"
- Summary of Activities 2009, Report 2010-1 p.149-170 (pdf, 22.4 MB)

2009: "Preliminary results of geological mapping, uranium-lead zircon dating, and micropaleontological and lead isotopic studies of volcanogenic massive sulphide-hosting stratigraphy of the Middle and Late Paleozoic Sicker and Lower Buttle Lake groups on Vancouver Island, British Columbia (NTS 092B/13, 092C/16, 092E/09, /16, 092F/02, /07)"
- Summary of Activites 2008, Report 2009-1 p.103-121 (pdf, 16.8MB)


2008: "Geological setting of volcanogenic massive sulphide occurrences in the Middle Paleozoic Sicker Group of the Cowichan Lake uplift, southern Vancouver Island, British Columbia"
- Summary of Activites 2007, Report 2008-1 p.77-92 (pdf, 26.3MB)


2007: "Geological Setting of Volcanogenic Massive Sulphide Occurrences in the Middle Paleozoic Sicker Group of the Southeastern Cowichan Lake Uplift (NTS 092B/13), Southern Vancouver Island"
- Geological Fieldwork 2006, Paper 2007-1 p.381-394 (pdf, 5.26MB)


2006: "Stratigraphic and Paleotectonic Studies of the Middle Paleozoic Sicker Group and Contained VMS Occurrences, Vancouver Island, British Columbia"
- Geological Fieldwork 2005, Paper 2006-1 p.331-335 (pdf, 302KB)

Final Deliverables
Ph.D. Thesis - T.W. Ruks
Stratigraphic and paleotectonic studies of Paleozoic Wrangellia and its contained volcanogenic massive sulfide (VMS) occurrences, Vancouver Island, British Columbia, Canada - University of British Columbia, 2015 - Available digitally through UBC (pdf, 145 MB)

Abstract: Wrangellia is a fundamental component of the North American Cordillera and contains significant mineral deposits, including Myra Falls (Nyrstar N.V.), which is currently the largest producing volcanogenic massive sulfide (VMS) deposit in western Canada. Understanding the evolution of Wrangellia is therefore important for understanding the crustal growth and metallogenic history of the North American continent, and in doing so, facilitating the discovery of new mineral wealth. Geochronological, lithogeochemical and Nd and Pb isotopic studies of the Paleozoic Wrangellia arc (PWA), Vancouver Island have significantly revised our understanding of the terrane, suggesting that the PWA comprises a progressively rifting Late Devonian through Early Permian oceanic volcanic arc complex developed above an east dipping subduction zone (modern coordinates) with Late Devonian through middle Mississippian, and Pennsylvanian through Early Permian pulses of bimodal volcanism and associated VMS mineralization. The relatively primitive lithogeochemical and Nd isotopic signatures of PWA intrusive and volcanic rocks indicate that the PWA originated in an oceanic arc environment close enough to a continental margin to undergo slight contamination via the subduction of continent derived sediments. Recently recognized, Pennsylvanian-Early Permian aged, VMS associated bimodal volcanic rocks in the PWA have lithogeochemical and Nd isotopic signatures indicative of derivation from more primitive and significantly hotter source melts than their Late Devonian counterparts, suggesting that Late Paleozoic volcanic rocks in the terrane are prospective for VMS mineralization. Lead isotope geochemistry of newly discovered VMS style mineralization in the PWA indicates that host areas for the new mineral occurrences are prospective for Myra Falls-like VMS deposits of Late Devonian-Early Mississippian age. Lead isotope geochemistry for recently recognized Pennsylvanian-Early Permian VMS mineralization in the PWA supports lithogeochemical and Nd isotopic arguments which suggest that Late Paleozoic bimodal volcanic rocks in the PWA were derived from more primitive melts than their Late Devonian-Early Mississippian counterparts, reflective of an origin in a progressively rifting, oceanic island arc environment.

 



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