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Polymetamorphism in the Dalradian of the central Scottish Highlands

Published online by Cambridge University Press:  01 May 2009

T. J. Dempster
Affiliation:
Grant Institute of Geology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, U.K.
B. Harte
Affiliation:
Grant Institute of Geology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, U.K.

Abstract

Systematic variations in both timing and conditions of metamorphism are observed in the Dalradian rocks of Central Perthshire, Scotland. Early (D2–D3 and syn-D3) relatively low-pressure metamorphism (550 °C, 7 kb) occurs in the Flat belt rocks of the Tay Nappe to the south, and later (post-D3) higher-pressure conditions (550 °C, 9 kb) dominate the Steep belt to the north. The latter appear to be superimposed on earlier low pressure assemblages (chloritoid–biotite) with the pressure increase probably relating to formation of the Tummel Steep Belt, possibly near 460 Ma. This polymetamorphism, in addition to the generally high pressures of Barrovian metamorphism throughout Perthshire, may account for the poor development of the metamorphic zonal pattern in this region compared to the eastern Dalradian.

Type
Articles
Copyright
Copyright © Cambridge University Press 1986

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References

Atherton, M. P. 1968. The variation in garnet, biotite and chlorite composition in medium grade pelitic rocks from the Dalradian, Scotland, with particular reference to zonation in garnet. Contributions to Mineralogy and Petrology 18, 347–71.CrossRefGoogle Scholar
Atherton, M. P. & Brotherton, M. S. 1982. Major element composition of the pelites of the Scottish Dalradian. Geological Journal. 17, 185221.CrossRefGoogle Scholar
Atherton, M. P. & Smith, R. A. 1979.Chloritoid–staurolite assemblages from Barrow's zones–Central Perthshire. Geological Magazine 116, 469–76.CrossRefGoogle Scholar
Baker, A. J. 1985. Pressures and temperatures of metamorphism in the eastern Dalradian. Journal of the Geological Society of London 142, 137–48.CrossRefGoogle Scholar
Baker, A. J. & Droop, G. T. R. 1983. Grampian metamorphic conditions deduced from mafic granulites and sillimanite–K-feldspar gneisses in the Dalradian of Glen Muick, Scotland. Journal of the Geological Society of London 140, 489–98.CrossRefGoogle Scholar
Barrow, G. 1893. On an intrusion of muscovite–biotite gneiss in the south-east Highlands of Scotland and its accompanying metamorphism. Quarterly Journal of the Geological Society of London 49, 330–58.CrossRefGoogle Scholar
Barrow, G. 1912. On the geology of lower Deeside and the Southern Highland Border. Proceedings of the Geologists' Association 23, 268–73.CrossRefGoogle Scholar
Bradbury, H. J. 1979. Relationships of migmatites to deformation and porphyroblast growth in the Dalradian of Tayside. In The Caledonides of the British Isles – Reviewed (ed. Harris, A. L., Holland, C. H. and Leake, B. E.), pp. 351–6. Geological Society of London: Scottish Academic Press.Google Scholar
Bradbury, H. J. 1985. The Caledonian metamorphic core: an Alpine model. Journal of the Geological Society of London 142, 129–36.CrossRefGoogle Scholar
Bradbury, H. J., Harris, A. L. & Smith, R. A. 1979. Geometry and emplacement of nappes in the Central Scottish Highlands. In The Caledonides of the British Isles – Reviewed (ed. Harris, A. L., Holland, C. H. and Leake, B. E.), pp. 213–20. Geological Society of London: Scottish Academic Press.Google Scholar
Brown, W. L. 1962. Peristerite unmixing in the plagioclases and the metamorphic facies series. Norsk Geologisk Tidsskrift 42, 354–82.Google Scholar
Chatterjee, N. D. 1972. The upper stability of the assemblage paragonite+quartz and natural occurrences. Contributions to Mineralogy and Petrology 34, 288303.CrossRefGoogle Scholar
Chinner, G. A. 1965. The kyanite isograd in Glen Clova, Angus, Scotland. Mineralogical Magazine 34, 132–43.CrossRefGoogle Scholar
Chinner, G. A. & Heseltine, F. J. 1979. The Grampide andalusite/kyanite isograd. Scottish Journal of Geology 15, 117–27.CrossRefGoogle Scholar
Chopin, C. & Schreyer, W. 1983. Magnesiocarpholite and magnesiochloritoid: two index minerals of pelitic blueschists and their preliminary phase relations in the model system MgO–Al2O3–SiO2–H2O. American Journal of Science 283A, 7296.Google Scholar
Cooper, A. F. 1972. Progressive metamorphism of metabasic rocks from the Haast Schist group of southern New Zealand. Journal of Petrology 13, 457–92.CrossRefGoogle Scholar
Crawford, M. L. 1974. Calcium zoning in almandine: a model based on plagioclase equilibria. In The Feldspars (ed. Mackenzie, W. S. and Zussman, J.), pp. 629–44. Manchester University Press.Google Scholar
Dempster, T. J. 1985 a. Uplift patterns and orogenic evolution in the Scottish Dalradian. Journal of the Geological Society of London 142, 111–28.CrossRefGoogle Scholar
Dempster, T. J. 1985 b. Garnet zoning and metamorphism of the Barrovian type area, Scotland. Contributions to Mineralogy and Petrology 89, 30–8.CrossRefGoogle Scholar
Droop, G. T. R. 1981. Alpine metamorphism of pelitic schists in the south-east Tauern Window, Austria. Schweizerische Mineralogische und Petrographische Mitteilungen 61, 237–73.Google Scholar
Ferry, J. M. & Spear, F. S. 1978. Experimental calibration of the partitioning of Fe and Mg between biotite and garnet. Contributions to Mineralogy and Petrology 66, 113–18.CrossRefGoogle Scholar
Franceschelli, M., Memmi, I. & Ricci, C. A. 1982. Ca distribution between almandine rich garnet and plagioclase in pelitic and psammite schists from the metamorphic basement of Northeastern Sardinia. Contributions to Mineralogy and Petrology 80, 285–95.CrossRefGoogle Scholar
Ghent, E. D. & Stout, M. Z. 1981. Geobarometry and geothermometry of plagioclase–biotite–garnet–muscovite assemblages. Contributions to Mineralogy and Petrology 76, 92–7.CrossRefGoogle Scholar
Harris, A. L., Bradbury, H. J. & McGonigal, M. H. 1976. The evolution and transport of the Tay Nappe. Scottish Journal of Geology 12, 103–13.CrossRefGoogle Scholar
Harte, B. 1980. Chloritoid–staurolite assemblages in Central Perthshire. Geological Magazine 117, 615–16.CrossRefGoogle Scholar
Harte, B., Booth, J. E., Dempster, T. J., Fettes, D. J., Mendum, J. R. & Watts, D. 1984. Aspects of the post-depositional evolution of Dalradian and Highland Border Complex rocks in the Southern Highlands of Scotland. Transactions of the Royal Society of Edinburgh, Earth Sciences 75, 151–63.CrossRefGoogle Scholar
Harte, B., Dempster, T. J. & Booth, J. E. 1985. P–T estimates and mineral facies variations in space and time in the central and SE Scottish Highlands. Journal of the Geological Society of London 142, 4.Google Scholar
Harte, B. & Hudson, N. F. C. 1979. Pelite facies series and the temperatures and pressures of Dalradian metamorphism in E. Scotland. In The Caledonides of the British Isles – Reviewed (ed. Harris, A. L., Holland, C. H. and Leake, B. E.), pp. 323–38. Geological Society of London: Scottish Academic Press.Google Scholar
Harte, B. & Johnson, M. R. W. 1969. Metamorphic history of Dalradian rocks in Glens Clova, Esk and Lethnot, Angus, Scotland. Scottish Journal of Geology 5, 5480.CrossRefGoogle Scholar
Hodges, K. V. & Spear, F. S. 1982. Geothermometry, geobarometry and the Al2SiO5 triple point at Mt. Moosilauke, New Hampshire. American Mineralogist 67, 1118–34.Google Scholar
Moles, N. 1985. Metamorphic conditions and uplift history in central Perthshire: evidence from mineral equilibria in the Foss celsian–barite–sulphide deposit, Aberfeldy. Journal of the Geological Society London 142, 3952.CrossRefGoogle Scholar
Newton, R. C. & Haselton, H. T. 1981. Thermodynamics of the garnet–plagioclase–Al2SiO5–quartz geobarometer. In Thermodynamics of Minerals and Melts (ed. Newton, R. C., Navrotsky, A. and Wood, B. J.), pp. 131–48. New York: Springer-Verlag.CrossRefGoogle Scholar
Pankhurst, R. J. & Pidgeon, R. T. 1976. Inherited isotope systems and the source region pre-history of early Caledonian granites in the Dalradian series of Scotland. Earth and Planetary Science Letters 31, 5568.CrossRefGoogle Scholar
Perkins, D. III, Westrum, E. F. Jr. & Essene, E. J. 1980. The thermodynamic properties and phase relations of some minerals in the system CaO–Al2O3–SiO2–H2O. Geochimica et Cosmochimica Acta 44, 6184.CrossRefGoogle Scholar
Powell, R. & Evans, J. A. 1983. A new geobarometer for the assemblage biotite–muscovite–chlorite–quartz. Journal of Metamorphic Petrology 1, 331–6.CrossRefGoogle Scholar
Richardson, S. W. & Powell, R. 1976. Thermal causes of the Dalradian metamorphism in the Central Highlands of Scotland. Scottish Journal of Geology 12, 237–68.CrossRefGoogle Scholar
Roberts, J. L. & Treagus, J. E. 1977. Polyphase generation of nappe structures in the Dalradian rocks of the southwest Highlands of Scotland. Scottish Journal of Geology 13, 237–54.CrossRefGoogle Scholar
Sivaprakash, C. 1982. Geothermometry and geobarometry of Dalradian metapelites and metabasites from the Central Scottish Highlands. Scottish Journal of Geology 18, 109–25.CrossRefGoogle Scholar
Sleep, N. H. 1979. A thermal constraint on the duration of folding with reference to Acadian geology, New England (U.S.A.). Journal of Geology 87, 583–9.CrossRefGoogle Scholar
Storre, B. & Nitsch, K.-H. 1974. Zur Stabilität von Margarit im system CaO–Al2O3–SiO2–H2O. Contributions to Mineralogy and Petrology 43, 124.CrossRefGoogle Scholar
Sturt, B. A. 1961. The geological structure of the area south of Loch Tummel. Quarterly Journal of the Geological Society of London 117, 131–56.CrossRefGoogle Scholar
Thomas, P. R. 1979. New evidence for a Central Highland root zone. In The Caledonides of the British Isles – Reviewed (ed. Harris, A. L., Holland, C. H. and Leake, B. E.), pp. 205–11. Geological Society of London: Scottish Academic Press.Google Scholar
Tilley, C. E. 1925. A preliminary survey of metamorphic zones in the southern Highlands of Scotland. Quarterly Journal of the Geological Society of London 81, 100–12.CrossRefGoogle Scholar
Van Breemen, O. & Piasecki, M. A. J. 1983. The Glen Kyllachy Granite and its bearing on the nature of the Caledonian Orogeny in Scotland. Journal of the Geological Society of London 140, 4762.CrossRefGoogle Scholar
Wells, P. R. A. & Richardson, S. W. 1979. Thermal evolution of metamorphic rocks in the Central Highlands of Scotland. In The Caledonides of the British Isles – Reviewed (ed. Harris, A. L., Holland, C. H. and Leake, B. E.), pp. 339–44. Geological Society of London: Scottish Academic Press.Google Scholar