Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-22T04:50:02.941Z Has data issue: false hasContentIssue false
  • English
  • Français

Significance of the early fabric in the contact metamorphic aureole of the 590 Ma Ben Vuirich Granite, Perthshire, Scotland

Published online by Cambridge University Press:  01 May 2009

P. W. G. Tanner
P. W. G. Tanner
Affiliation:
Department of Geology & Applied Geology, University of Glasgow, Glasgow, G12 8QQ, U.K.
Get access Rights & Permissions [Opens in a new window]

Abstract

An early fabric is preserved in pseudomorphs of contact metamorphic cordierite and andalusite found in hornfelsed Dalradian rocks at the NW margin of the Ben Vuirich Granite. As previous work had suggested that this fabric may be of regional tectonic (D1) origin, and taken as evidence that a pre-590 Ma (Neoproterozoic) orogenic event had affected the Dalradian Supergroup, the textures found in the hornfelses and their porphryoblasts are illustrated and described in detail. Three types of hornfels are recorded: unspotted, cordierite-, and andalusite-bearing. Cordierite was altered to mica, garnet, and kyanite, and andalusite pseudomorphed by kyanite, during the subsequent D2 regional metamorphism.

The early fabric is finely spaced and associated with a weak shape fabric, except in the higher grade hornfelses where it is more intensely developed and formed during the deformation of irregularly shaped, cross-cutting granitic veinlets. It is concluded that the hornfels fabric is probably bedding modified by intrusion-related deformation, rather than a D1 fabric parallel to bedding. The implication of this finding is that intrusion of the Ben Vuirich Granite occurred during the Vendian (c.650 Ma) rifting phase, at about the time that the Tayvallich lavas were being deposited, and before any significant deformation of the Dalradian rocks had taken place. There is no unambiguous evidence to show that the early fabric in the hornfels at Ben Vuirich formed during a Precambrian, regional-scale, deformation of the Dalradian block.

Type
Articles
Information
Geological Magazine , Volume 133 , Issue 6 , November 1996 , pp. 683 - 695
Copyright
Copyright © Cambridge University Press 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Barrow, G., Grant, Wilson J. S. & Cunningham, Craig B. A. 1905. The geology of the country round Blair Atholl, Pitlochry, and Aberfeldy. (Explanation of Sheet 55). Memoirs of the Geological Survey of Scotland.Google Scholar
Biermann, C. 1984. On the parallelism of bedding and cleavage in deformed rocks from the Internal Zone of the Betic Cordilleras – S. E. Spain. Geologie en Mijnbouw 63, 75–83.Google Scholar
Bradbury, H. J., Smith, R. A. & Harris, A. L. 1976. ‘Older’ granites as time-markers in Dalradian evolution. Journal of the Geological Society, London 132, 677–84.CrossRefGoogle Scholar
Church, W. R. 1990. Discussion on a high precision U-Pb age for the Ben Vuirich granite: implications for the evolution of the Scottish Dalradian Supergroup. Journal of the Geological Society, London 148, 205.Google Scholar
Crawford, M. L. & Mark, L. E. 1982. Evidence from metamorphic rocks for overthrusting. Pennsylvania Piedmont, USA. Canadian Mineralogist 20, 333–47.Google Scholar
Ellis, D. J. & Obata, M. 1992. Migmatite and melt segregation at Cooma, New South Wales. Transactions of the Royal Society of Edinburgh: Earth Sciences 83, 95–106.CrossRefGoogle Scholar
England, P. C. & Thompson, A. B. 1984. Pressure-temperature-time paths of regional metamorphism. Part 1, heat transfer during the evolution of regions of thickened crust. Journal of Petrology 25, 894–928.CrossRefGoogle Scholar
Gibbons, W. & Harris, A. L. (eds). 1994. A revised correlation of Precambriam rocks in the British Isles. Geological Society, London, Special Report no. 22.CrossRefGoogle Scholar
Halliday, A. N., Graham, C. M., Aftalion, M. & Dymoke, P. 1989. The depositional age of the Dalradian Supergroup: U-Pb and Sm-Nd isotopic studies of the Tayvallich Volcanics, Scotland. Journal of the Geological Society, London 146, 3–6.CrossRefGoogle Scholar
Harker, A. 1932.Metamorphism. London: Methven.Google Scholar
Harker, R. I. 1954. Further data on the petrology of the pelitic homfelses of the Carn Chuinneag-Inchbae region, Ross-shire, with special reference to the status of almandine. Geological Magazine 91, 445–62.CrossRefGoogle Scholar
Harker, R. I. 1970. Preservation of folding in the Carn Chuinneag-Inchbae hornfels. Scottish Journal of Geology 6, 226–27.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
Harwood, D. S. & Larson, R. R. 1969. Variations in delta index of cordierite around the Cupsuptic Pluton, west-central Maine. American Mineralogist 54, 896–908.Google Scholar
Hollister, L. S. 1969. Metastable paragenetic sequence of andalusite, kyanite, and sillimanite, Kwoiek area British Columbia. American Journal of Science 267, 352–70.CrossRefGoogle Scholar
Holst, T. B. 1985. Implications of a large flattening strain for the origin of a bedding-parallel foliation in the Early Proterozoic Thomson Formation, Minnesota. Journal of Structural Geology 7, 375–83.CrossRefGoogle Scholar
Keighin, C. W., Morey, G. B. & Goldich, S. S. 1972. East central Minnesota. In Geology of Minnesota: A Centennial Volume (eds Sims, P.K. and Morey, G.B.), pp. 240–55. Minnesota Geological Survey.Google Scholar
Pantin, H. M. 1961. The stratigraphy and structure of the Blair Atholl – Ben a’Gloe area, Perthshire, Scotland. Transactions of the Royal Society of New Zealand 88, 597–622.Google Scholar
Peach, B. N., Gunn, W., Clough, C. T., Hinxman, L. W., Crampton, C. B. & Anderson, E. M. 1912. The geology of Ben Wyvis, Carn Chuinneag, Inchbae and the surrounding country. (Explanation of Sheet 93). Memoirs of the Geological Survey of Scotland.Google Scholar
Paterson, S. R. & Fowler, T. K. Jr. 1993. Re-examining pluton emplacement processes. Journal of Structural Geology 15, 191–206.CrossRefGoogle Scholar
Paterson, S. R. & Tobisch, O. T. 1988. Using pluton ages to date regional deformations: problems with commonly used criteria. Geology 16, 1108–1111.2.3.CO;2>CrossRefGoogle Scholar
Paterson, S. R., Tobisch, O. T. & Vernon, R. H. 1991. Emplacement and deformation of granitoids during volcanic arc construction in the Foothills terrane, central Sierra Nevada, California. Tectonophysics 191, 89–110.CrossRefGoogle Scholar
Paterson, S. R. & Vernon, R. H. 1995. Bursting the bubble of ballooning plutons: A return to nested diapirs emplaced by multiple processes. Geological Society of America Bulletin 107, 1356–80.2.3.CO;2>CrossRefGoogle Scholar
Paterson, S. R., Vernon, R. H. & Fowler, T. K. Jr. 1991. Aureole tectonics In Contact Metamorphism (ed. Kerrich, D.M.), pp. 673–722. Reviews of Mineralogy, 26, Mineralogical Society of America.CrossRefGoogle Scholar
Pattison, D. R. M. & Tracy, R. J. 1991. Phase equilibria and thermobarometry of metapelites. In Contact Metamorphism (ed.Kerrick, D. M.), pp. 105–206. Reviews in Mineralogy, 26. Mineralogical Society of America.CrossRefGoogle Scholar
Rogers, G., Dempster, T. J., Bluck, B. J. & Tanner, P. W. G. 1989. A high precision U-Pb age for the Ben Vuirich granite: implications for the evolution of the Scottish Dalradian Supergroup. Journal of the Geological Society, London 146, 789–98.CrossRefGoogle Scholar
Rogers, G., Dempster, T. J., Bluck, B. J. & Tanner, P. W. G. 1990. Reply to a discussion on a high precision U-Pb age for the Ben Vuirich granite: implications for the evolution of the Scottish Dalradian Supergroup. Journal of the Geological Society, London 148, 205–6.Google Scholar
Shepherd, J. 1973. The structure and structural dating of the Carn Chuinneag intrusion, Ross-shire. Scottish Journal of Geology 9, 63–88.CrossRefGoogle Scholar
Soper, N. J. & England, R. W. 1995. Vendian and Riphean rifting in NW Scotland. Journal of the Geological Society, London 152, 11–14.CrossRefGoogle Scholar
Sylvester, A. G., Oertel, G., Nelson, C. A. & Christie, J. M. 1978. Papoose Flat pluton: A granitic blister in the Inyo Mountains, California. Geological Society of America Bulletin 89, 1205–19.2.0.CO;2>CrossRefGoogle Scholar
Tanner, P. W. G. 1995. New evidence that the Lower Cambrian Leny Limestone at Callander, Perthshire, belongs to the Dalradian Supergroup, and a reassessment of the status of the Highland Border complex. Geological Magazine 132, 473–83.CrossRefGoogle Scholar
Tanner, P. W. G. & Leslie, A. G 1994. A pre–D2 age for the 590 Ma Ben Vuirich Granite in the Dalradian of Scotland. Journal of the Geological Society, London 151, 209–12.CrossRefGoogle Scholar
Tilley, C. E. 1935. The role of kyanite in the ‘hornfels zone’ of the Carn Chuinneag granite (Ross-shire). Mineralogical Magazine 24, 92–97.CrossRefGoogle Scholar
Tobisch, O. T., Saleeby, J. B. & Fiske, R. S. 1986. Structural history of continental volcanic arc rocks, eastern Sierra Nevada, California: a case for extensional tectonics. Tectonics 5, 65–94.CrossRefGoogle Scholar
Treagus, J. E. 1987. The structural evolution of the Dalradian of the Central Highlands of Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences 78, 1–15.CrossRefGoogle Scholar
Van Bosse, J. Y. & Williams-Jones, A. E. 1988. Chemographic relationships of biotite and cordierite in the McGerrigle thermal aureole, Gaspe, Quebec. Journal of Metamorphic Geology 6, 65–7.CrossRefGoogle Scholar
Vernon, R. H., Paterson, S. R. & Foster, D. 1993. Growth and deformation of porphyroblasts in the Foothills terrane, central Sierra Nevada, California: negotiating a microstructural minefield. Journal of Metamorphic Geology 11, 203–22.CrossRefGoogle Scholar
Wilson, D. & Shepherd, J. 1979. The Carn Chuinneag granite and its aureole. In The Caledonides of the British Isles – reviewed, (eds Harris, A. L., Holland, C. H. and Leake, B. E.), pp 669–75. Geological Society, London, Special Publication no. 8.Google Scholar
Zen, E-An. 1995. Crustal magma generation and low-pressure high-temperature regional metamorphism in an extensional environment; possible application to the Lachlan Belt, Australia. American Journal of Science 295, 851–74.CrossRefGoogle Scholar