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Volume 46 Number 3
  • E-ISSN: 1365-2478

Abstract

Known mineral occurrences in northern Vancouver Island are typically hosted in volcanic units of the Bonanza Group. At a local scale, the mineralization is associated with advanced argillic bedrock alteration and is often intimately related to porphyry intrusions. On a larger scale, faults are thought to exert the most significant control on the distribution of mineralized host rocks. Poor exposures and a complex glacial history limit the use of traditional methods of geological mapping and mineral exploration in this region and to date geophysical methods have been under‐utilized. Here we present findings from four standard geophysical (gravity, magnetics, electromagnetics and seismic refraction) methods, recently deployed here to elucidate the subsurface geology, as well as to identify new targets for base metal exploration.

Results at two different sites show that the integrated interpretation of geophysical data, constrained by physical rock property measurements, yields detailed images of the subsurface at a fraction of the cost of drilling. At one site, east of Rupert Inlet, the final subsurface model shows that the Bonanza Group is not nearly as extensive as previously presumed. An extension of the Holberg Fault is identified some 50 km east of the visibly mapped outcrop and an extensive zone of alteration around the fault is recognized. Furthermore, a number of the methods provide support for the existence of a porphyry dike at this site. At the second site, north of Rupert Inlet, magnetic and electromagnetic data prove effective at mapping alteration and locating shear zones beneath a relatively thin drift cover. Together, these results help outline a strategy for exploration in drift‐covered terrains and show that a redirection of exploration effort is warranted in the case of northern Vancouver Island.

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2002-04-19
2024-04-28

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References

  1. ArmstrongR.L., MullerJ.E., HarakelJ.E.MuehlenbachsK.1985. The Neogene Alert Bay Volcanic Belt of northern Vancouver Island, Canada: Descending‐plate‐edge volcanism in the Arc‐Trench Gap. Journal of Volcanology and Geothermal Research26,75–97.
    [Google Scholar]
  2. BarkerF., Sutherland BrownA., BudahnJ.R.PlafkerG.1989. Back arc with Frontal arc component origin of Triassic Karmutsen Basalt, British Columbia, Canada. Geochemical Geology75,81–102.
    [Google Scholar]
  3. BobrowskyP.T., BestM., DunnC.E., HuntleyD.H., LoweC., RobertsM.C., SeemannD.A.SibbickS.J.1995. Integrated drift exploration studies on northern Vancouver Island. In: Geological Fieldwork 1994 (eds B. Grant and J.M. Newell). B.C. Ministry of Energy, Mines and Petroleum Resources, Paper 1995‐1, pp. 23–33.
  4. BobrowskyP.T.MeldrumD.G.1994. Preliminary drift exploration studies, northern Vancouver Island (92L/6, 92L/11). In: Geological Fieldwork 1993 (eds B. Grant and J.M. Newell). B.C. Ministry of Energy, Mines and Petroleum Resources, Paper 1994‐1, pp. 87–99.
  5. DobrinM.B.1960. Introduction to Geophysical Prospecting. McGraw‐Hill Book Co.
  6. FittermanD.V.StewartM.T.1986. Transient electromagnetic soundings for ground water. Geophysics15,995–1005.
    [Google Scholar]
  7. FlemingJ.1992. Porphyry copper‐molybdenum‐gold mineralization at Island Copper, Vancouver Island, B.C. In: Porphyry copper model. Northwest Mining Association, 1992 Short Course, Tucson, Arizona and Spokane, Washington.
  8. GardnerM.C., BergmanS.C., CushingG.W., MacKevettE.M.Jr, PlafkerG., CampbellR.B., DodsC.J., McClellandW.C.MuellerP.A.1988. Pennsylvanian pluton stitching of Wrangellia and the Alexander Terrane, Wrangell Mountains, Alaska. Geology16,967–971.
    [Google Scholar]
  9. Geological Survey of Canada
    Geological Survey of Canada1990. GRAMA, Geological Survey of Canada, Open File 2290, Ottawa, Canada.
  10. Geonics Ltd
    Geonics Ltd1991. Geonics Protem 47 Operating Manual. Geonics Limited, 8‐1745 Meyerside Drive, Mississauga, Ontario L57 1C6, Canada.
  11. HammackJ.L., NixonG.T., KoyanagiV., PayieG.J., PantaleyevA., MasseyN.W.D., HamiltonJ.V.HaggertJ.W.1994. Preliminary geology of the Quatsino — Port McNeill area, northern Vancouver Island. B.C. Ministry of Energy, Mines, and Petroleum Resources, Open File 1994‐15.
  12. Van Der HeydenP.1991. A middle Jurassic to early Tertiary Andean‐Sierran Arc model for the Coast Belt of British Columbia. Tectonics11,82–97.
    [Google Scholar]
  13. HoltzR.D.KovacsW.D.1981. An Introduction to Geotechnical Engineering. Prentice‐Hall Inc., p. 15.
  14. HowesD.E.1981. Terrain inventory and geological hazards: northern Vancouver Island. B.C. Ministry of Environment, APD Bulletin 5.
  15. HowesD.E.1983. Late Quaternary sediments and geomorphic history of northern Vancouver Island, British Columbia. Canadian Journal of Earth Sciences20,57–65.
    [Google Scholar]
  16. Interpex Limited
    Interpex Limited1994. TEMIXGL User Manual, transient electromagnetic data interpretation software. Interpex Limited, P.O. Box 839, Golden, Colorado 80402, USA.
  17. JonesD.L., SilberlingN.J.HillhouseJ.W.1977. Wrangellia — a displaced terrane in Northwestern North America. Canadian Journal of Earth Sciences14,2565–2577.
    [Google Scholar]
  18. KeareyP.BrooksM.1984. An Introduction to Geophysical Exploration. Blackwell Scientific Publications.
  19. KerrD.E.SibbickS.J.1992. Preliminary results of drift exploration studies in the Quatsino (92L/12) and the Mount Milligan (93N/1E, 93O/4W) areas. In: Geological Fieldwork 1991 (eds B. Grant and J.M. Newell). B.C. Ministry of Energy, Mines and Petroleum Resources, Paper 1992‐1, pp. 341–347.
  20. LoweC., BestM.E., SeemannD.A.BobrowskyP.T.1995. Shallow subsurface mapping using an integrated geophysical approach, northern Vancouver Island, British Columbia. Geological Survey of Canada, Open File 3195.
  21. MongerJ.W.H., PriceR.A.Templeman‐KluitD.J.1982. Tectonic accretion and the origin of the two major metamorphic and plutonic welts in the Canadian Cordillera. Geology10,70–75.
    [Google Scholar]
  22. MorelliC. (compiler) 1974. International gravity standardization net 1974. International Association of Geodesy, Special Publication No. 4, Paris.
  23. MullerJ.E., CameronB.E.B.NorthcoteK.E.1981. Geology and mineral deposits of the Nootka Sound map area (92E), Vancouver Island, British Columbia. Geological Survey of Canada, Paper 80‐16.
  24. MullerJ.E., NorthcoteK.E.CarlisleD.1974. Geology and mineral deposits of Alert Bay — Cape Scott map area, Vancouver Island, British Columbia. Geological Survey of Canada, Paper 74‐8.
  25. NixonG.T., HammackJ.L., HamiltonJ.V.JenningsH.1993. Preliminary geology of the Mahatta Creek area, northern Vancouver Island (92L/5). In: Geological Fieldwork 1992 (eds B. Grant and J.M. Newell). B.C. Ministry of Energy, Mines and Petroleum Resources, Paper 1993‐1, pp. 17–35.
  26. PalackyG.J.StewartL.E.1990. Mapping of Quaternary sediments in northeastern Ontario using ground electromagnetic methods. Geophysics55,1595–1604.
    [Google Scholar]
  27. PantaleyevA., BobrowskyP.T., NixonG.T.SibbickS.J.1994. Northern Vancouver Island integrated project. In: Geological Fieldwork 1993 (eds B. Grant and J.M. Newell). B.C. Ministry of Energy, Mines and Petroleum Resources, Paper 1994‐1, pp. 59–62.
  28. PantaleyevA.KoyanagiV.M.1994. Advanced argillic alteration in Bonanza volcanic rocks, northern Vancouver Island — lithologic and permeability controls. In: Geological Fieldwork 1993 (eds B. Grant and J.M. Newell). B.C. Ministry of Energy, Mines, and Petroleum Resources, Paper 1994‐1, pp. 101–110.
  29. Rimrock Geophysics Incorporated
    Rimrock Geophysics Incorporated1994. Users Guide to SIPIN, SIEDT, and SIPT2, V‐4.1. Rimrock Geophysics Inc., 12372 W Louisiana Ave., Lakewood, Colorado 80228.
  30. RoddickJ.A.1980. Geology of northeast Alert Bay map area, British Columbia. Geological Survey of Canada, Open File 722.
  31. ScromedaN., KatsubeJ.BestM.1996. Electrical resistivity of rock samples from Vancouver Island, British Columbia. In: Current Research 1996‐E. Geological Survey of Canada, pp. 19–22.
  32. TelfordW.M., GeldartL.P.SheriffR.E.1990. Applied Geophysics. Cambridge University Press.
  33. WheelerJ.O.McFeelyP. (compilers) 1991. Tectonic assemblage map of the Canadian Cordillera and adjacent parts of the United States of America. Geological Survey of Canada, Map 1712A, scale 1:2 000 000.
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Integrated geophysics for mineral exploration in drift‐covered volcanic terrains: examples from northern Vancouver Island, Canada[Link]
Geophysical Prospecting 46, 201 (0198); https://doi.org/10.1046/j.1365-2478.1998.00093.x
/content/journals/10.1046/j.1365-2478.1998.00093.x
/content/journals/10.1046/j.1365-2478.1998.00093.x
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