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Igneous layering in a dacite: on the origin and significance of Layer Cake Mountain, Kelowna, B.C., Canada

Published online by Cambridge University Press:  05 July 2018

J. D. Greenough  and
J. V. Owen
J. D. Greenough
Affiliation:
Department of Earth and Ocean Sciences, University of British Columbia, Okanagan University College, 333 College Way, Kelowna, BC, V1V 1V7, Canada
J. V. Owen
Affiliation:
Department of Geology, Saint Mary's University, Halifax, NS, B3H 3C3, Canada
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Abstract

A Tertiary, dacitic volcanic land-form in Kelowna, British Columbia, shows layering that has not been recognized elsewhere. Layering is expressed as thin (0.5 m) layers separated by thick (4.5 m) layers exposed along a weathered fault scarp. The major elements show that both thick and thin layers are dacitic and geochemically very similar. Trace element modelling indicates that thin layers formed from thick layers via crystal fractionation involving removal of plagioclase, biotite and magnetite in the proportions 75:20:5, and with only 12% fractionation. The thin layers represent segregation veins generated during crystallization of the dacite. They formed when the crystal mush at the bottom of the upper crust successively, thermally contracted, fractured and foundered, siphoning evolved interstitial liquid from the mush into the horizontal crack. Cooling of the segregation veins led to further fracturing. Later, fluids following these fractures altered the thin layers and precipitated secondary carbonate minerals. The altered thin layers weather preferentially, thus visually accentuating the small primary chemical differences between thick and thin layers. The scale of layering, mode of formation and differentiation mechanisms appear different from those in felsic magma chambers and it is unclear how common this phenomenon is. However, similar layering is more easily identified and commonly developed in mafic lava flows.

Keywords

igneous layeringdacitefluidsdifferentiationKelownaCanada
Type
Research Article
Information
Mineralogical Magazine , Volume 62 , Issue 6 , December 1998 , pp. 731 - 742
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1998

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References

Anderson, A.T., Swihart, G.H., Artioli, G. and Geiger, C.A. (1984) Segregation vesicles, gas filter pressing, and igneous differentiation. J. Geol., 92, 55–72.CrossRefGoogle Scholar
Barbey, P. Bertrand, J.-M., Angoua, S. and Dautel, D. (1989) Petrology and U/Pb geochronology of the Telohat migmatites, Aleksod, Central Hoggar, Algeria. Contrib. Mineral. Petrol., 101, 207–19.CrossRefGoogle Scholar
Cameron, K.L. and Cameron, M. (1986) Whole-rock/groundmass differentiation trends of rare earth elements in high-silica rhyolites. Geochim. Cosmochim. Acta, 50, 759–69.CrossRefGoogle Scholar
Church, B.N. (1973) Geology of the White Lake Basin. British Columbia Department of Mines and Petroleum Resources, Bulletin 61, 120 pp. plus photographs and maps.Google Scholar
Church, B.N. (1980) Geology of the Kelowna Tertiary Outlier (West Half). Province of British Columbia, Ministry of Energy, Mines and Petroleum Resources, Preliminary Map 39.Google Scholar
Church, B.N. (1981) Geology of the Kelowna Tertiary Outlier (East Half). Province of British Columbia, Ministry of Energy, Mines and Petroleum Resources, Preliminary Map 45.Google Scholar
Church, B.N. (1982) Volcanology and structure of Tertiary Outliers in South-Central British Columbia. Trip 5. pp. 5-1 to 5–46.Google Scholar
Fujimaki, H. Tatsumoto, M. and Aoki, K. (1984) Partition coefi cients of Hf, Zr, and REE between phenocrysts and groundmass. Proceedings of the 14th Lunar and Planetary Science Conference, Part 2, J. Geophys. Res., 89, supplement, B662–72.CrossRefGoogle Scholar
Gast, P.W. (1968) Trace-element fractionation and the origin of tholeiitic and alkaline magma types. Geochim. Cosmochim. Acta, 32, 1057–86.CrossRefGoogle Scholar
Giannetti, B. and Luhr, J.F. (1983) The white trachytic tuff of Roccamonfina volcano (Roman Region, Italy). Contrib. Mineral. Petrol., 84, 235–52.CrossRefGoogle Scholar
Gill, J.B. (1981) Orogenic Andesites and Plate Tectonics. Springer-Verlag, New York, 390 pp.CrossRefGoogle Scholar
Greenough, J.D. and Dostal, J. 1992 a. Cooling history and differentiation of a thick North Mountain Basalt flow (Nova Scotia, Canada). Bull. Volcanol., 55, 63–73.CrossRefGoogle Scholar
Greenough, J.D. and Dostal, J. (1992 b) Layered rhyolite bands in a thick North Mountain Basalt flow: the products of silicate liquid immiscibility? Mineral. Mag., 56, 309-18.Google Scholar
Greenough, J.D. and Roed, M.A. (1995) Geological history of bedrock in the Kelowna area. In Geology of the Kelowna Area and Origin of the Okanagan Valley, British Columbia. Kelowna Geology Committee, Kelowna, Canada, 27–39.Google Scholar
Helz, R.T. (1980) Crystallization history of Kilauea Iki lava lake as seen in drill core recovered in 1967–1979. Bull. Volcanol., 43, 675–701.CrossRefGoogle Scholar
Helz, R.T. (1987) Differentiation behaviour of Kilauea Iki lava lake, Kilauea Volcano, Hawaii: an overview of past and current work. In Magmatic Processes: Physicochemical Principles, (Mysen, B.O., ed. ). The Geochemical Society, Special Publication No. 1, 241–58.Google Scholar
Henderson, P. (1984) General geochemical properties and abundances of the rare earth elements. In Rare Earth Element Geochemistry, (Henderson, P., ed.). Elsevier, New York, 1–32.Google Scholar
Hildreth, W. (1979) The Bishop Tuff: evidence for the origin of compositional zonation in silicic magma chambers. Geological Society of America Special Paper 180, 43–75.CrossRefGoogle Scholar
Hildreth, W. (1981) Gradients in silicic magma chambers: implications for lithospheric magmatism. J. Geophys. Res., 8, 10153-92.CrossRefGoogle Scholar
Irvine, T.N. and Baragar, W.R.A. (1971) A guide to the chemical classification of common volcanic rocks. Canad. J. Earth Sci., 8, 523–48.CrossRefGoogle Scholar
Kruger, F.J. and Smart, R. (1987) Diffusion of trace elements during bottom crystallization of double-diffusive convection systems: the magnetitite layers of the Bushveld Complex. J. Volcanol. Geotherm. Res., 34, 133–42.CrossRefGoogle Scholar
Lemarchand, F., Villemant, B. and Calas, G. (1987) Trace element distribution coefficients in alkaline series. Geochim. Cosmochim. Acta, 51,, 1071-81.CrossRefGoogle Scholar
Longerich, H.P. (1995) Analysis of pressed pellets of geological samples using wavelength-dispersive X-ray fluorescence spectrometry. X-Ray Spectrom., 24, 123–36.CrossRefGoogle Scholar
Longerich, H.P., Jenner, G.A., Fryer, B.J. and Jackson, S.E. (1990) Inductively coupled plasma-mass spectrometric analysis of geologic samples: a critical evaluation based on case studies. Chem. Geol., 83, 105–18.CrossRefGoogle Scholar
Mahood, G.A. (1981) Chemical evolution of a Pleistocene rhyolitic center: Sierra La Primavera, Jalisco, Mexico. Contrib. Mineral. Petrol., 77, 129–49.CrossRefGoogle Scholar
Mahood, G.A. and Hildreth, W. (1983) Large partition coefficients for trace elements in high-silica rhyolites. Geochim. Cosmochim. Acta, 47, 11–30.CrossRefGoogle Scholar
Marsh, B.D. (1990) Igneous processes in sills. In Proceedings ; Pacific Rim Congress 90; Australasian Institute of Mining and Metallurgy, Victoria, Australia, Pacific Rim Congress, 2, 83–91.Google Scholar
McBirney, A.R. (1985) Further considerations of double-diffusive stratification and layering in the Skaergaard Intrusion. J. Petrol., 26, 993–1001.CrossRefGoogle Scholar
McBirney, A.R. and Noyes, R.M. (1979) Crystallization and layering of the Skaergaard Intrusion. J. Petrol., 20, 487–554.CrossRefGoogle Scholar
Möller, P. (1988) The dependence of partition coefficients on differences of ionic volumes in crystal-melt systems. Contrib. Mineral. Petrol., 99, 62–9.CrossRefGoogle Scholar
Philpotts, J.A. and Schnetzler, C.C. (1970) Phenocrystmatrix partition coefficients for K, Rb, Sr and Ba with applications to anorthosite and basalt genesis. Geochim. Cosmochim. Acta, 34,, 307-22.CrossRefGoogle Scholar
Propach, G. (1976) Models of filter differentiation. Lithos, 9, 203–9.CrossRefGoogle Scholar
Schnetzler, C.C. and Philpotts, J.A. (1970) Partitioning coefficients of rare-earth elements between igneous matrix material and rock-forming mineral phenocrysts - II. Geochim. Cosmochim. Acta, 34, 331–40.CrossRefGoogle Scholar
Tempelman-Kluit, D.J. (1989) Geology, Penticton, British Columbia. Geological Survey of Canada, Map 1736A.Google Scholar
Wilkinson, L., Hill, M., Welna, J.P. and Birkenbeuel, G.K. (1992) SYSTAT for Windows: Statistics, Version 5 Edition, SYSTAT Inc., Evanston, IL, 750 pp.Google Scholar
Wörner, G., Beusen, J.-M., Duchateau, N., Gijbels, R. and Schmincke, H. -U. (1983) Trace element abundances and mineral/melt distribution coefficients in phonolites from Laacher See Volcano (Germany). Contrib. Mineral. Petrol., 84, 152–73.Google Scholar
Wright, T.L. and Okamura, R.T. (1977) Cooling and crystallization of tholeiitic basalt, 1965 Makaopuhi Lava Lake, Hawaii. U. S. Geol. Surv. Prof. Paper 1004, 78 pp.CrossRefGoogle Scholar