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Geology and geochemistry of the volcanic rocks of the Pioneer Formation, Bridge River area, southwestern British Columbia (Canada)

Published online by Cambridge University Press:  01 May 2009

J. Dostal  and
B. N. Church
J. Dostal
Affiliation:
Department of Geology, Saint Mary‘s University, Halifax, Nova Scotia B3H 3C3, Canada
B. N. Church
Affiliation:
Geological Survey Branch, B.C. Ministry of Energy, Mines and Petroleum Resources, Victoria, British Columbia V8V 1X4, Canada
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Abstract

The Pioneer Formation of southwestern British Columbia (Canada) is composed predominantly of middle to late Triassic pillow basalts. These rocks are an integral part of the Cadwallader and the Bridge River terranes that were delaminated from the oceanic lithosphere and stacked against the continental margin of the North American craton by middle Jurassic time. The basalts are underlain and locally intercalated with ribbon cherts and argillites that range in age from Mississippian to Triassic. The Triassic basalts are conformably overlain by clastic sediments containing late Carnian–Norian conodont fauna. The tholeiitic basalts have enriched and depleted REE patterns, and have been emplaced in an oceanic environment. The compositional variations of the basalts are attributed to dynamic partial melting of source rocks that are believed to have been part of the rising mantle diapir. According to our model, after initial melting in the garnet stability field, the mantle diapir rose up to the spinel stability field where it underwent subsequent melting. The reconstructed stratigraphy of the Bridge River area may be interpreted in terms of an oceanic plate moving over a mantle plume and into a trench where offscraping preserved tectonic lenses of the subducting plate in an accretionary prism.

Type
Articles
Information
Geological Magazine , Volume 131 , Issue 2 , March 1994 , pp. 243 - 253
Copyright
Copyright © Cambridge University Press 1994

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References

Archibald, D. A., Garver, J. I. & Schiarizza, P. 1991. Dating of blueschist from the Bridge River complex, southwestern British Columbia, and its tectonic implications. Geological Society of America Abstracts with Programs 23, A136.Google Scholar
Armstrong, R. L. 1988. Mesozoic and early Cenozoic magmatic evolution of the Canadian Cordillera. In Processes in Continental Lithospheric Deformation (ed. Clark, S. P. Jr), pp. 55–91. Geological Society of America, Special Paper no. 218.CrossRefGoogle Scholar
Barr, D. A. 1980. Gold in the Canadian Cordillera. CIM Bulletin, 73(818), 59–76.Google Scholar
Cairnes, C. E. 1937. Geology and mineral deposits of the Bridge River mining camp, British Columbia. Geological Survey of Canada, Memoir no. 213, 140 pp.CrossRefGoogle Scholar
Calon, T. J., Malpas, J. G. & McDonald, R. 1990. The anatomy of the Shulaps ophiolite. In Geological Fieldwork 1989, pp. 375–86. B.C. Ministry of Energy, Mines and Petroleum Resources.Google Scholar
Church, B. N. 1987. Geology and mineralization of the Bridge River mining camp. B.C. Ministry of Energy, Mines and Petroleum Resources, Geological Survey Branch, 1986, Paper 1987–1, 23–9.Google Scholar
Church, B. N. 1993. Geology and mineralization in the Bridge River mining camp. B.C. Ministry of Energy, Mines and Petroleum Resources, Paper (in press).Google Scholar
Church, B. N., Gaba, R. G., Hanna, M. J. & James, D. A. R. 1988. Geological reconnaissance in the Bridge River mining camp. Geological Fieldwork 1987, pp. 93–100. B.C. Ministry of Energy, Mines and Petroleum Resources.Google Scholar
Church, B. N. & Pettipas, A. R. 1989. Research and exploration in the Bridge River mining camp. Geological Fieldwork, 1988, pp. 105–14. B.C. Ministry of Energy, Mines and Petroleum Resources. Paper 1989–1.Google Scholar
Cordey, F. 1986. Radiolarian ages from the Cache Creek and Bridge River complexes and from chert pebbles in Cretaceous conglomerates, southwestern British Columbia. Current Research, Part A, Geological Survey of Canada, Paper 86–1 A, 595–602.Google Scholar
Cordey, F. & Schiarizza, P. 1993. Long-lived Panthalassic remnant: the Bridge River accretionary complex, Canadian Cordillera. Geology 21, 263–6.2.3.CO;2>CrossRefGoogle Scholar
Cordey, F., Mortimer, N., Deweever, P. & Monger, J. W. H. 1987. Significance of Jurassic radiolarians from the Cache Creek terrane, British Columbia. Geology 15, 1151–4.2.0.CO;2>CrossRefGoogle Scholar
Dostal, J., Baragar, W. R. A. & Dupuy, C. 1986. Petrogenesis of the Natkusiak continental basalts, Victoria Island, N.W.T. Canadian Journal of Earth Sciences 23, 622–32.CrossRefGoogle Scholar
Ellam, R. M. 1992. Lithospheric thickness as a control on basalt geochemistry. Geology 20, 153–6.2.3.CO;2>CrossRefGoogle Scholar
Garver, J. I., Till, A. B., Armstrong, R. L. & Schiarizza, P. 1989. Permo-Triassic blue-schist in the Bridge River complex, southern British Columbia. Geological Society of America, Abstracts with Programs 21, 82.Google Scholar
Jenner, G. A., Longerich, H. P., Jackson, S. E. & Fryer, B. J. 1990. ICP-MS: a powerful new tool for high-precision trace element analysis in Earth Sciences; evidence from analysis of selected USGS standards. Chemical Geology 83, 113–48.CrossRefGoogle Scholar
Kleinspehn, K. L. 1984. Cretaceous sedimentation and tectonics, Tyaughton–Methow basin, southwestern British Columbia. Canadian Journal of Earth Sciences 22, 154–74.CrossRefGoogle Scholar
Langmuir, C. H., Bender, J. F., Bence, A. E., Hanson, G. N. & Taylor, S. R. 1977. Petrogenesis of basalts from the FAMOUS area: Mid-Atlantic Ridge. Earth and Planetary Science letters 36, 133–56.CrossRefGoogle Scholar
Leitch, C. H. B., Der Heyden, P., Godwin, C. I., Armstrong, R. L. & Harakal, J. E. 1991. Geochronometry of the Bridge River Camp, southwestern British Columbia. Canadian Journal of Earth Sciences 28, 195–208.CrossRefGoogle Scholar
Leterrier, J., Maury, R. C., Thonon, P., Girard, D. & Marchal, M. 1982. Clinopyroxene composition as a method of identification of the magmatic affinities of paleo-volcanic series. Earth and Planetary Science Letters 59, 139–54.CrossRefGoogle Scholar
McKenzie, D. P. & O'Nions, R. K. 1991. Partial melt distributions from inversion of rare earth element concentrations. Journal of Petrology 32, 1021–91.CrossRefGoogle Scholar
Monger, J. W. H. 1985. Structural evolution of the south-western Intermontane belt, Ashcroft and Hope mapareas, British Columbia. Geological Survey of Canada Paper 8–1A, 349–58.Google Scholar
Monger, J. W. H. & Berg, H. C. 1987. Lithotectonic Terrane Map of Western Canada and Southeastern Alaska. United States Geological Survey, Map MF-1874-B.Google Scholar
Monger, J. W. H., Price, R. A. & Tempelman-Kluit, D. J. 1982. Tectonic accretion and the origin of the two major metamorphic and plutonic belts in the Canadian Cordillera. Geology 10, 70–5.2.0.CO;2>CrossRefGoogle Scholar
Nelson, J. A. & Mihalynuk, M. 1993. Cache Creek ocean: closure or enclosure? Geology 21, 173–6.2.3.CO;2>CrossRefGoogle Scholar
Pearce, J. A. 1975. Basalt geochemistry used to investigate past tectonic settings on Cyprus. Tectonophysics 25, 41–67.CrossRefGoogle Scholar
Pearce, J. A. 1983. The role of subcontinental lithosphere in magma genesis at active continental margins. In Continental Basalts and Mantle Xenoliths (eds Hawkesworth, C. J. and Norry, M. J.), pp. 230–49. Nantwich: Shiva.Google Scholar
Potter, C. J. 1986. Origin, accretion and post-accretionary history of the Bridge River terrane, southwestern British Columbia. Tectonics 5, 1027–41.CrossRefGoogle Scholar
Ray, G. E. 1986. The Hozameen fault system and related Coquihalla serpentine belt of southwestern British Columbia. Canadian Journal of Earth Sciences 23, 1022–41.CrossRefGoogle Scholar
Roddick, J. A. & Hutchison, W. W. 1973. Pemberton (east half) map-area, British Columbia. Geological Survey of Canada, Paper no. 73–17, 21 pp.CrossRefGoogle Scholar
Rusmore, M. E. 1987. Geology of the Cadwallader Group and the Intermontane–Insular superterrane boundary, southwestern British Columbia. Canadian Journal of Earth Sciences 24, 2279–91.CrossRefGoogle Scholar
Rusmore, M. E., Potter, C. J. & Umhoefer, P. J. 1988. Middle Jurassic terrane accretion along the westernedge of the Intermontane superterrane, southwestern British Columbia. Geology 16, 891–4.2.3.CO;2>CrossRefGoogle Scholar
Rusmore, M. E. & Woodsworth, G. J. 1991. Distribution and tectonic significance of Upper Triassic terranes in the eastern Coast Mountains and adjacent Intermontane Belt, British Columbia. Canadian Journal of Earth Sciences 28, 532–41.CrossRefGoogle Scholar
Schiarizza, P., Gaba, R. G., Glover, J. K. & Garver, J. I. 1989. Geology and mineral occurrences of the Tyaughton Creek area. Geological Fieldwork, 1988, pp. 115–30. B.C. Ministry of Energy, Mines and Petroleum Resources, Paper 1989–1.Google Scholar
Sun, S. S. 1982. Chemical composition and origin of the Earth's primitive mantle. Geochimica et Cosmochimica Acta 46, 179–92.CrossRefGoogle Scholar
Sun, S. S. & McDonough, W. F. 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In Magmatism in the Ocean Basins (eds Saunders, A. D. and Norry, M. J.), pp. 313–45. Geological Society of London, Special Publication no. 42.Google Scholar
Umhoefer, P. J. 1990. Stratigraphy and tectonic setting of the upper part of the Cadwallader terrane, southwesten British Columbia. Canadian Journal of Earth Sciences, 27, 702–11.CrossRefGoogle Scholar
Watson, S. & McKenzie, D. P. 1991. Melt generation by plumes: a study of Hawaiian volcanism. Journal of Petrology 32, 501–37.CrossRefGoogle Scholar
Wheeler, J. O. & McFeely, P. 1987. Tectonic assemblage map of the Canadian Cordillera and adjacent portion, of the United States of America. Geological Survey of Canada, Open File 1565, scale 1:2000000.Google Scholar
Winchester, J. A. & Floyd, P. A. 1976. Geochemical magma type discrimination: application to altered and metamorphosed basic igneous rocks. Earth and Planetary Science Letters 28, 459–69.CrossRefGoogle Scholar
Wood, D. A. 1979. Dynamic partial melting and its application to the petrogenesis of basalts erupted in Iceland, the Faeroe Islands, the Isle of Skye (Scotland) and the Troodos Massif (Cyprus). Geochimica et Cosmochimica Acta 43, 1031–46.CrossRefGoogle Scholar
Wright, R. L., Nagel, J. J. & McTaggart, K. C. 1982. Alpine ultramafic rocks of southwestern British Columbia. Canadian Journal of Earth Sciences 19, 1156–73.CrossRefGoogle Scholar