Hostname: page-component-586b7cd67f-rcrh6 Total loading time: 0 Render date: 2024-11-27T17:55:44.508Z Has data issue: false hasContentIssue false
  • English
  • Français

The chemical character of the Late Caledonian Donegal Granites, Ireland, with comments on their genesis

Published online by Cambridge University Press:  11 January 2017

Azman A. Ghani  and
Michael P. Atherton
Azman A. Ghani
Affiliation:
Department of Earth and Ocean Sciences, University of Liverpool, Liverpool L69 3GP, UK, e-mail: [email protected]
Michael P. Atherton
Affiliation:
Department of Earth and Ocean Sciences, University of Liverpool, Liverpool L69 3GP, UK, e-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

The Late Caledonian granites of Donegal are all intruded into metasediments of the Dalradian Supergroup of Neoproterozoic age, which were metamorphosed and deformed during the Grampian Phase of the Caledonian orogeny at c. 470-460 m.y. They were intruded in a singular pulse well after the main tectonic event, apparently peaking at 407-402 m.y.; importantly after the strong collision of Laurentia with Baltica on closure of the Iapetus Ocean. The plutons are mainly made up of granodiorite and granite, and are all ‘I’ type, but different to Cordilleran ‘I’ types of the eastern Pacific margin. Major element chemistry indicates they are high-K calc-alkaline rocks with a large range in SiO2 content. However three of the plutons (Fanad, Thorr, Ardara), have very high Ba and Sr contents, even higher than Mainland Scotland counterparts; they are high Ba-Sr plutons. Three plutons (Barnesmore, Rosses, Trawenagh Bay) are evolved and are low-Ba-Sr types, while one (Main Donegal) has atypical, intermediate characteristics. The origin of the magmas is still much debated; here we suggest slab breakoff on Iapetus Ocean closure accounts for the special compositions of these magmas and the other major features of Late Caledonian granitic magmatism, including the singular intrusion peak and the associated appinite-lamprophyre suite.

Keywords

Appenitehigh Ba-Sr graniteslab break-off
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 97 , Issue 4 , 2008 , pp. 437 - 454
Copyright
Copyright © The Royal Society of Edinburgh 2008

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

Atherton, M.P. 1999. Slab breakoff: a consistent model for Caledonian Late Granite magmatism in the British Isles. Fourth Hutton Symposium abstracts. Editions BRGM 290, 76.Google Scholar
Atherton, M.P., McCourt, W.J., Sanderson, L.M. & Taylor, W.P. 1979. The geochemical character of the segmented Peruvian Coastal Batholith and associated volcanics. In Atherton, M.P. & Tarney, J. (eds) Origin of granite batholiths - geochemical evidence, 45-64. Nantwich: Shiva Publishing Ltd.CrossRefGoogle Scholar
Atherton, M.P. & Ghani, A.A. 2002. Slab breakoff: a model for Caledonian, Late Granite syncollisional magmatism in the ortho-tectonic (metamorphic) zone of Scotland and Donegal, Ireland. Lithos 62, 65-85.Google Scholar
Atherton, M.P. & Petford, N. 1993. Generation of sodium-rich magmas from newly underplated basaltic crust. Nature 362, 144-6.Google Scholar
Atkin, B.P. 1977. A mineralogical and chemical study of the paragenesis of opaque minerals in the Donegal granites and their aureole rocks, Eire. Unpublished Ph.D. Thesis, University of Liverpool.Google Scholar
Bailey, E.B. & Maufe, H.B. 1916. The geology of Ben Nevis and Glencoe and the surrounding country (Expl. Sheet 53). Memoir of the Geological Survey of Scotland. Edinburgh: HMSO.Google Scholar
Barker, F. 1979. Trondhjemite: definition, environment and hypothesis of origin. In Barker, F. (ed.) Trondhjemite, dacites and related rocks, 1-12. Amsterdam: Elsevier.Google Scholar
Bowden, P., Batchelor, R.A., Chappell, B.W., Didier, J. & Lameyre, J. 1984. Petrological, geochemical and source criteria for the classification of granitic rocks: a discussion. Physics of Earth and Planetary Interiors 35, 1-11.Google Scholar
Brown, G. C., Thorpe, R.S. & Webb, P.C. 1984. The geochemical characteristics of granitoids in contrasting arcs and comments on magma sources. Journal of the Geological Society, London 141, 411-26.Google Scholar
Brown, P.E. 1991. Caledonian and earlier magmatism. In Craig, G.Y. (ed.) Geology of Scotland, 229-96. London: The Geological Society.Google Scholar
Canning, J.C., Henney, P.J., Morrison, M.A. & Gaskarth, J.W. 1996. Geochemistry of late Caledonian minettes from northern Britain: implications for the Caledonian sub-continental litho-spheric mantle. Mineralogical Magazine 60, 221-36.Google Scholar
Canning, J.C., Henney, P.J., Morrison, M.A., VanCalsteren, P.W.C., Gaskarth, J.W. & Swarbrick, A. 1998. The Great Glen Fault: a major vertical lithospheric boundary. Journal of the Geological Society, London 155, 425-8.Google Scholar
Chappell, B.W. & White, A.J.R. 1974. Two contrasting granite types. Pacific Geology 8, 173-4.Google Scholar
Chappell, B.W. & White, A.J.R. 1992. ‘I’ and ‘S’ type granites in the Lachlan fold belt. Transactions of the Royal Society of Edinburgh: Earth Sciences 83, 1-26.Google Scholar
Condon, D.J., Hodges, K.V., Alsop, G.I. & White, A. 2006. Laser ablation ““A/^Ar dating of metamorphic fabrics in the Caledonides of North Ireland. Journal of the Geological Society, London 163, 337-45.Google Scholar
Davies, J.H. & von Blankenburg, F. 1995. Slab breakoff, a model of lithosphère detachment and its test in the magmatism and deformation of collisional orogens. Earth and Planetary Science Letters 129, 85-102.Google Scholar
De la Roche, H., Leterrier, J., Gran de Claude, P. & Marchel, M. 1980. A classification of volcanic and plutonie rocks using RI R2 diagrams and major element analyses - its relationship and current nomenclature. Chemical Geology 29, 183-210.Google Scholar
Dempsey, C.S. 1987. The petrology and geochemistry of the Caledonian granitoids of the Barnesmore complex, County Donegal. Unpublished Ph.D. Thesis, Queens University, Belfast.Google Scholar
Dempsey, C.S., Halliday, A.N. & Meighan, I.G. 1990. Combined Sm-Nd and Rb-Sr isotope systematics in the Donegal granitoids and their petrogenetic implications. Geological Magazine 127, 75-80.Google Scholar
Dewey, J.F. 1969. Evolution of the Appalachian/Caledonian orogen. Nature 111, 124-9.Google Scholar
Dewey, J.F. & Mange, M. 1999. Petrography of Ordovician and Silurian sediments in the western Irish Caledonides: traces of a short-lived Ordovician continent-arc collision orogeny and the evolution of the Laurentian Appalachian-Caledonian margin. In MacNiocaill, C. & Ryan, P.D. (eds) Continental Tectonics. Geological Society, London, Special Publication 164, 55-107.CrossRefGoogle Scholar
Dewey, J.F. & Shackleton, R.H. 1984. A model for the evolution of the Grampian tract in the early Caledonides and Appalachians. Nature, 311, 115-21.Google Scholar
Fernandez Dávila, M. 1969. The petrology and mode of employment of the Rosgillpluton, Co. Donegal, Eire. Unpublished M.Sc. Thesis, University of Liverpool.Google Scholar
Fowler, M.B., Henney, P.J., Derbyshire, D.P.F. & Greenwood, P.B. 2001. Petrogenesis of high Ba-Sr granites: the Rogart pluton Sutherland. Journal of the Geological Society, London 158, 521 34.Google Scholar
Fowler, M.B. & Henney, P.J. 1996. Mixed Caledonian appinite magmas: implications for lamprophyre fractionation and high Ba-Sr granite genesis. Contributions to Mineralogy and Petrology 126, 199-215.Google Scholar
Ghani, A.A. 1997. Petrology and geochemistry of the Donegal Granites, Ireland. Unpublished Ph.D. Thesis, University of Liverpool.Google Scholar
Green, D.H. & Wallace, M.E. 1988. Mantle metasomatism by ephemeral carbonatite melts. Nature 336, 459-62.Google Scholar
Hall, A. 1971. The relationship between geothermal gradient and the composition of granitic magmas in orogenic belts. Contributions to Mineralogy and Petrology 32, 186-92.Google Scholar
Halliday, A.N., Stephens, W.E., Hunter, R.H., Menzies, M.A., Dicken, A.P. & Hamilton, P.J. 1985. Isotopie and chemical constraints on the building of the deep Scottish lithosphère. Scottish Journal of Geology 21, 465-91.Google Scholar
Halliday, A.N. & Stephens, W.E. 1984. Crustal controls on the genesis of the 400Ma old Caledonian granites. Physics of the Earth and Planetary Interiors 35, 84-104.Google Scholar
Harmon, R.S., Halliday, A.N., Clayburn, J.A.P. & Stephens, W.E. 1984. Chemical and isotopie systematics of the Caledonian intrusions of Scotland and Northern England: a guide to magma source regions and magma-crust interaction. Philosophical Transactions of the Royal Society of London A310, 709-12.Google Scholar
Hauri, E.H., Shimizu, N., Dieu, J.J. & Hart, S.R. 1993. Evidence for hotspot-related carbonatite metasomatism in the oceanic upper mantle. Nature 365, 221-7.CrossRefGoogle Scholar
Hill, R.I., Campbell, I.H., Davies, G.F. & Griffiths, R.W. 1992. Mantle plumes and continental tectonics. Science 256, 186-93.Google Scholar
Hutton, D.H.W. 1988. Granite emplacement mechanisms and tectonic controls from deformation studies. Transactions of the Royal Society of Edinburgh: Earth Sciences 79, 245-55.Google Scholar
Hutton, D.H.W., Stephens, W.E., Yardley, B., McErlean, M. & Halliday, A.N. 1993. Ratagain Plutonic Complex. In May, F., Peacock, J.D., Smith, D. 1. & Barber, A.J. (eds) Geology of the Kintail district. Memoir for Sheet 72 Wand part of 71E (Scotland), 52-6. London: HMSO.Google Scholar
Jaques, J. & Reavy, J.R. 1994. Caledonian plutonism and major lineaments in the S.W. Scottish Highlands. Journal of the Geological Society, London 151, 955-69.Google Scholar
McKerrow, W.S., MacNiocaill, C. & Dewey, J.F. 2000. The Caledonian Orogeny redefined. Journal of the Geological Society, London 157, 1149-54.Google Scholar
Mitchell, R.H. 1995. Melting experiments on a sanidine phlogopite lamproite at 4-7 GPa and their bearing on the source of 1am-proitic magmas. Journal of Petrology 36, 1445-74.Google Scholar
O’Connor, P.J., Long, C. B. & Evans, J.A. 1987. Rb-Sr whole rock isochron studies of the Barnesmore and Fanad plutons, Donegal, Ireland. Geological Journal, 11, 11-23.Google Scholar
Oglethorpe, R.D.J. 1987. A mineralogical and chemical study of the interactions between granite magma andpelitic country rock, Thorr pluton Co. Donegal, Eire. Unpublished Ph.D. Thesis, University of Liverpool. Google Scholar
Pitcher, W. S. 1953. The Rosses granitic ring-complex, County Donegal, Eire. Proceedings of the Geological Association 64, 153-82.Google Scholar
Pitcher, W.S. 1982. Granite type and tectonic environment. In Hsu, K. J. (ed.) Mountain building Processes, Ï9-4Q. London: Academic Press.Google Scholar
Pitcher, W.S. 1987. Granites and yet more granites forty years on. Geologie Rundschau 76, 51-79Google Scholar
Pitcher, W.S., Atherton, M.P., Cobbing, E.J. & Beckinsale, R.D. 1985. Magmatism at a Plate Edge: The Peruvian Andes. Glasgow: Blackie Halsted.Google Scholar
Pitcher, W.S. & Berger, A.R. 1972. The geology of Donegal: a study of granite emplacement and unroofing. New York: Wiley Inter-science.Google Scholar
Price, A.R. & Pitcher, W.S. 1999. The Trawenagh Bay Granite: a multipulse, inclined sheet intruded in the flank of a synplutonic shear zone. Irish Journal of Earth Sciences, 17, 57-60.Google Scholar
Read, H.H. 1961. Aspects of Caledonian magmatism in Britain. Liverpool and Manchester Geological Journal 2, 653-83.Google Scholar
Roberts, M.P. & Clemens, J.D. 1993. Origin of high-potassium, calc-alkaline, ‘I’ type granitoids. Geology 21, 825-8.2.3.CO;2>CrossRefGoogle Scholar
Rogers, G. & Dunning, G.R. 1991. Geochronology of appinitic and related granitic magmatism in the W. Highlands of Scotland: constraints on the timing of transcurrent fault movements. Journal of the Geological Society, London 148, 17-27.Google Scholar
Soper, N.J. 1986. The Newer Granite problem: a geotectonic view. Geological Magazine 123, 227-36.Google Scholar
Soper, N.J., Strachan, R.A., Holdsworth, R.E., Gayer, R.A. & Greiling, R.O. 1992. Sinistrai transpression and the Silurian closure of Iapetus. Journal of the Geological Society, London 149, 871-80.CrossRefGoogle Scholar
Stephens, W.E. & Halliday, A.N. 1984. Geochemical contrasts between Late Caledonian granitoid plutons of northern, central and southern Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences 75, 259-73.Google Scholar
Tarney, J. & Jones, C. E. 1994. Trace element geochemistry of orogenic igneous rocks and crustal growth models. Journal of the Geological Society, London 151, 855-68.Google Scholar
Thirlwall, M.F. 1988. Geochronology of Late Caledonian magmatism in northern Britain. Journal of the Geological Society, London 145, 951-68.Google Scholar
von Blanckenburg, F. & Davies, J.H. 1996. Feasibility of double slab breakoff (Cretaceous and Tertiary) during Alpine convergence. Eclogue geologae Helvetica 89, 111-27.Google Scholar
Walker, G.P.L. & Leedal, G.P. 1954. The Barnesmore granite complex, Co. Donegal. Scientific Proceedings of the Royal Dublin Society 26, 207-43.Google Scholar
White, A.J.R. & Chappell, B.W. 1983. Granitoid types and their distributions in the Lachlan Fold Belt; southeastern Australia. In Roddick, J.A. (ed.) Circum-Pacific plutonie terranes. Geological Society of America Memoir 159, 21-34.Google Scholar