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Geochemistry of biotite in metabentonites as an age discriminant, indicator of regional magma sources and potential correlating tool

Published online by Cambridge University Press:  05 July 2018

R. A. Batchelor
R. A. Batchelor*
Affiliation:
School of Geography & Geosciences, University of St Andrews, Irvine Building, North Street, St Andrews, Fife KY16 9AL, UK
*
* E-mail: [email protected]
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Abstract

The chemical composition of unaltered biotites extracted from 18 Lower Palaeozoic metabentonites from Sweden, Norway and Scotland was determined. Discrimination based on FeO, MgO and TiO2 proved able to separate the metabentonites on the basis of their stratigraphical age. A triangular discrimination diagram using MgO, FeO and Al2O3 classified the biotites as calc-alkaline. Independent support for the discriminant power of FeO, MgO and TiO2 in biotite comes from Sr isotope ratios and Sr concentration data from cognate apatite crystals. Within this dataset Caradocian and Llandoverian metabentonites have unique biotite compositions, while Wenlockian samples can be characterized to a lesser degree. Biotite composition also supported the correlation of a pair of metabentonites from Norway known to form part of the same horizon. Biotite in metabentonites preserves the chemical signature of the host magmas in which it crystallized and can be used to discriminate between metabentonites of different ages and provenance.

Keywords

biotitegeochemistrymetabentoniteschemostratigraphy.
Type
Research Article
Information
Mineralogical Magazine , Volume 67 , Issue 4 , August 2003 , pp. 807 - 817
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2003

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References

Abdel-Rahman, A.-F.M. (1994 Nature of biotites from alkaline, calc-alkaline and peraluminous magmas. Journal of Petrology, 35, 525—541.CrossRefGoogle Scholar
Bailey, S.W. (editor) (1984 Micas. Reviews in Mineralogy , 13. Mineralogical Society of America, Washington, D.C.Google Scholar
Batchel or, R.A. and Clarkson, E.E.N. (1993 Geochemistry of a Silurian metabentonite and associated apatite from the North Esk Inlier, Pentland Hills. Scottish Journal of Geology, 29, 123—130.CrossRefGoogle Scholar
Batchelor, R.A. and Evans, J. (2003 Rare Earth Element and Sr/Nd isotope geochemistry of primary apatite crystals in metabentonites from Dob's Linn, Southern Scotland. Scottish Journal of Geology (in press).CrossRefGoogle Scholar
Batchelor, R.A. and Jeppsson, L. (1994 Late Llandovery bentonites from Gotland, Sweden, as chemos tratigraphic markers. Journa l of the Geological Society of London, 151, 741—746.CrossRefGoogle Scholar
Batchelor, R.A. and Jeppsson, L. (1999 Wenlock metabentonites from Gotland, Sweden: geochemistry, sources and potential as chemostratigraphic markers. Geological Magazine, 136, 661—669.CrossRefGoogle Scholar
Batchelor, R.A. and Weir, J.A. (1988 Metabentonite geochemistry: magmatic cycles and graptolite extinctions at Dob's Linn, Southern Scotland. Transactions of the Royal Society of Edinburgh, Earth Sciences, 79, 19—41.CrossRefGoogle Scholar
Batchelor, R.A., Weir, J.A. and Spjeldnæs, N. (1995 Geochemistry of Telychian metabentonites from Vik, Ringerike District, Oslo Region. Norsk Geologisk Tidsskrift, 75, 219—228.Google Scholar
Bergman, S.C. (1987 Lamproites and other potassiumrich igneous rocks: a review of their occurrence, mineralogy and geochemistry. Pp. 103—190 in: Alkaline Igneous Rocks (Fitton, J.G. and B.Upton, G.J., editors). Special Publication 30, Geological Society, London.Google Scholar
Chang, L.L.L., Howie, R.A. and Zussman, J. (1995 Non Silicates . Rock Forming Minerals, vol. 5B. Longman Group Ltd., London.Google Scholar
Deer, W.A., Howie, R.A. and Zussman, J. (1962 Sheet Silicates . Rock Forming Minerals, vol. 3. Longmans, London.Google Scholar
Deer, W.A., Howie, R.A. and Zussman, J. (1992 An Introduction to the Rock-forming Minerals , 2nd edition. Longman Scientific & Technical, Harlow, Essex.Google Scholar
Fuge, R. (1977 On the behaviour of fluorine and chlor ine dur ing magmatic differentiat ion. Contributions to Mineralogy and Petrology, 61, 245—49.CrossRefGoogle Scholar
Hagemann, F. and Spjeldnæs, N. (1955 The Middle Ordovician of the Oslo Region, Norway. 6. Notes on bentonites (K-bentonites) from the Oslo-Asker district. Norsk Geologisk Tidsskrift, 35, 29—52.Google Scholar
Haynes, J.T. (1994 The Ordovician Deicke and Millbrig K-bentonites beds of the Cincinnati Arch and the Southern Valley and Ridge province. Geological Society of America, Special Paper , 290.Google Scholar
Haynes, J.T., Melson, W.G. and Kunk, M.J. (1995 Composition of biotite phenocrysts in Ordovician tephras cast doubt on the proposed trans-Atlantic correlation of the Millbrig K-bentonite (United States) and the Kinnekulle K-bentonite (Sweden. Geology, 23, 847—850.2.3.CO;2>CrossRefGoogle Scholar
Huff, W.D., Morgan, D.J. and Rundle, C.C. (1996 Silurian K-bentonites of the Welsh Borderlands: geochemistry, mineralogy and K-Ar ages of illitization. British Geological Survey, Technical Report, WG/96/45.Google Scholar
Laufeld, S. (1974 Reference localities for palaeontology and geology in the Silurian of Gotland. Sveriges Geologiska Undersökning , C705, 1—172.Google Scholar
Nockolds, S.R. (1947 The relation between chemical composition and paragenesis in the biotite micas of igneous rocks. American Journal of Sciences, 245, 401—420.Google Scholar
Oliver, G.G.J. and Leggett, J.K. (1980 Metamorphism in an accretionary prism: prehnite-pumpellyite facies metamorphism of the Southern Uplands of Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences, 71, 235—246.CrossRefGoogle Scholar
Oliver, G.G.J., Smellie, L.J., Thomas, L.J., Casey, D.M., Kemp, A.A.E., Evans, L.J., Baldwin, J.R. and Hepworth, B.C. (1984 Early Palaeozoic metamorphic history of the Midland Valley, Southern Uplands-Longford Down massif and the Lake District, British Isles. Transactions of the Royal Society of Edinburgh: Earth Sciences, 75, 245—258.CrossRefGoogle Scholar
Oliver, G.G.J. (2001 Reconstruction of the Grampian episode in Scotland: its place in the Caledonian Orogeny. Tectonophysics, 332, 23—49.CrossRefGoogle Scholar
Ross, C.S. and Shannon, E.V. (1926 The minerals of bentonites and related clays and their physical properties. American Ceramic Society Journal, 9, 77—96.CrossRefGoogle Scholar
Weaver, C.E. (1963 Interpretative value of heavy minerals from bentonites. Journal of Sedimentary Petrology, 33, 343—349.Google Scholar
Yen, F. and Goodwin, J.H. (1976 Correlation of tuff layers in the Green River Formation, Utah, using biotite compositions. Journal of Sedimentar y Petrology, 46, 345—35.Google Scholar