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The Newer Granite problem revisited: a transtensional origin for the Early Devonian Trans-Suture Suite

Published online by Cambridge University Press:  01 February 2008

P. E. BROWN ,
P. D. RYAN ,
N. J. SOPER  and
N. H. WOODCOCK
P. E. BROWN*
Affiliation:
School of Geography & Geosciences, St Andrews KY16 9AL, Scotland, UK
P. D. RYAN
Affiliation:
Department of Earth & Ocean Sciences, National University of Ireland, Galway, Ireland
N. J. SOPER
Affiliation:
Gam's Bank, Threshfield, Skipton, N. Yorks BD23 5NP, England, UK
N. H. WOODCOCK
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, England, UK
*
*Author for correspondence: [email protected]
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Abstract

The origin of the Newer Granites is long-standing problem. In the Caledonian orthotectonic zone the intrusions span the period of late orogenic convergence and uplift, but attempts to relate them as a group to late Iapetan subduction have been unsuccessful. A range of rock types is represented, mainly with I-type affinities, and granodiorite is the most voluminous. In contrast, granitic intrusions south of the Moniaive shear zone in Scotland and also in the north of England have significant S-type characteristics, span the trace of the Iapetus suture and have ages in the range 400–390 Ma, significantly younger than intrusions to the north. We refer to these younger granitic intrusions, along with others of similar character along-strike to the southwest, as the Trans-Suture Suite. We explore the link between the Trans-Suture Suite and recently recognized orogen-wide sinistral transtension in the Early Devonian period. Importantly, the Trans-Suture Suite intrusions are accompanied by an intense suite of lamprophyre dykes, the origin of which is to be sought in extension, decompression and heating of enriched Avalonian sub-continental lithosphere. In some instances the granite intrusions carry clots of lamprophyric origin and the Criffel body is particularly important in being continuously zoned from an I-type with lamprophyric enclaves to an S-type interior. We propose that generation of these lamprophyres during transtension advected heat into the base of the crust to produce the S-type component of the Trans-Suture Suite. Modelling presented shows that generation of voluminous S-type magmas requires the coincidence of several factors: hydrated sub-continental lithospheric mantle preserved during ‘soft’ collision under the Trans-Suture Suite zone; thermal relaxation to remove any subduction refrigeration; crust composed of juvenile volcanogenic material; and Devonian transtension. Our models suggest that if hydration pre-dated transtension then only small granitic bodies could be produced, unless the zone of lamprophyre generation extends beyond the rift zone. The emplacement of the Trans-Suture Suite intrusions overlapped the Acadian deformation period that succeeded the transtensional episode during which the granite magmas were generated.

Keywords

granitetranstensiontrans-suture suitelamprophyreAcadian
Type
Original Article
Information
Geological Magazine , Volume 145 , Issue 2 , March 2008 , pp. 235 - 256
Copyright
Copyright © Cambridge University Press 2008

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References

Annen, C. & Sparks, R. S. J. 2002. Effects of repetitive emplacement of basalt intrusions on thermal evolution and melt generation in the crust. Earth and Planetary Science Letters 203, 937–55.CrossRefGoogle Scholar
Atherton, M. P. & Ghani, A. A. 2002. Slab breakoff: a model for Caledonian, Late Granite syn-collisional magmatism in the orthotectonic (metamorphic) zone of Scotland and Donegal, Ireland. Lithos 62, 65–85.CrossRefGoogle Scholar
Aydin, A. & Nur, A. 1982. Evolution of pull-apart basins, and their scale independence. Tectonics 1, 91–106.CrossRefGoogle Scholar
Barnes, R. P., Lintern, B. C. & Stone, P. 1989. Timing and regional implications of deformation in the Southern Uplands of Scotland. Journal of the Geological Society, London 77, 203–22.Google Scholar
Barnes, R. P., Phillips, E. R. & Boland, M. P. 1995. The Orlock Bridge Fault in the Southern Uplands of southwest Scotland: a terrane boundary? Geological Magazine 132, 523–9.CrossRefGoogle Scholar
Barnes, R. P., Rock, N. M. S. & Gaskarth, J. W. 1986. Late Caledonian dyke swarms in Southern Scotland: new field, petrological and geochemical data for the Wigtown Peninsula, Galloway. Geological Journal 21, 101–25.CrossRefGoogle Scholar
Bevins, R. E. & Merriman, R. J. 1988. Compositional controls on co-existing prehnite–actinolite and prehnite–pumpellyite facies assemblages in the Tal y fan metabasite intrusion, North Wales: implications for Caledonian metamorphic field gradients. Journal of Metamorphic Geology 6, 17–39.CrossRefGoogle Scholar
Bottrell, S. H., Greenwood, P. B., Yardley, B. W. D., Shepherd, T. J. & Spiro, B. 1990. Metamorphic and post-metamorphic fluid flow in the low-grade rocks of the Harlech Dome, North Wales. Journal of Metamorphic Geology 8, 131–43.CrossRefGoogle Scholar
Bradley, D. C., Tucker, R. D., Lux, D., Harris, A. G. & McGregor, D. C. 2000. Migration of the Acadian orogen and foreland basin across the Northern Appalachians. U.S. Geological Survey Professional Paper 1615, 49 pp.Google Scholar
Brown, P. E. 1991. Caledonian and earlier magmatism. In Geology of Scotland (ed. Craig, G. Y.), pp. 229–96. Geological Society of London.Google Scholar
Brown, P. E., Miller, J. A. & Soper, N. J. 1964. Age of the principal intrusions of the Lake District. Proceedings of the Yorkshire Geological Society 34, 331–42.CrossRefGoogle 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 lithospheric mantle. Mineralogical Magazine 60, 221–36.CrossRefGoogle Scholar
Canning, J. C., Henney, P. J., Morrison, M. A., Van Calsteren, 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.CrossRefGoogle Scholar
Chappell, B. W. & White, A. J. R. 1974. Two contrasting granite types. Pacific Geology 8, 173–4.Google Scholar
Coleman, D. S., Gray, W. & Glazner, A. F. 2004. Rethinking the emplacement and evolution of zoned plutons: geochronologic evidence for incremental assembly of the Tuolemne intrusive suite, California. Geology 32, 433–6.CrossRefGoogle Scholar
Cooper, D. C., Lee, M. K., Fortey, M. J., Cooper, A. H. & Rundle, C. C. 1988. The Crummock Water aureole: a zone of metasomatism and source of ore metals in the English Lake District. Journal of the Geological Society, London 145, 523–40.CrossRefGoogle Scholar
Cox, R. A., Dempster, T. J., Bell, B. R. & Rogers, G. 1996. Crystallisation of the Shap granite: evidence from zoned K-feldspar megacrysts. Journal of the Geological Society, London 153, 625–35.CrossRefGoogle Scholar
Dewey, J. F. 2002. Transtension in arcs and orogens. International Geological Review 44, 402–39.CrossRefGoogle Scholar
Dewey, J. F. & Strachan, R. A. 2003. Changing Silurian–Devonian relative plate motion in the Caledonides: sinistral transpression to sinistral transtension. Journal of the Geological Society, London 160, 219–29.CrossRefGoogle Scholar
Dunham, K. C. 1974. Granite beneath the Pennines in North Yorkshire. Proceedings of the Yorkshire Geological Society 40, 191–4.CrossRefGoogle Scholar
Dunham, K. C. 1990. Geology of the Northern Pennine Ore field; Volume 1, Tyne to Stainmore. Economic Memoir of the British Geological Survey, England and Wales, Sheets 19 and 25. Second edition.Google Scholar
Dunham, K. C., Dunham, A. C., Hodger, B. L. & Johnson, G. A. L. 1965. Granite beneath Visean sediments with mineralization at Rookhope, northern Pennines. Quarterly Journal of the Geological Society of London 121, 383–417.CrossRefGoogle Scholar
Elsdon, R. & Kennan, P. S. 1979. Geochemistry of Irish granites. In The Caledonides of the British Isles – reviewed (eds Harris, A. L., Holland, C. H. & Leake, B. E.), pp. 713–16. Geological Society of London, Special Publication no. 8.Google Scholar
Evans, J. A. 1996. Dating the transition of smectite to illite in Palaeozoic mudrocks using the Rb–Sr whole-rock technique. Journal of the Geological Society, London 153, 101–8.CrossRefGoogle Scholar
Fitch, F. J. & Miller, J. A. 1965. Age of the Weardale granite. Nature 208, 743–45.CrossRefGoogle Scholar
Fowler, M. B. 1988. Elemental evidence for crustal contamination of mantle-derived Caledonian syenite by metasediment anatexis and magma mixing. Chemical Geology 69, 1–16.CrossRefGoogle 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.CrossRefGoogle 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.CrossRefGoogle Scholar
Freeman, B., Klemperer, S. L. & Hobbs, R. W. 1988. The deep structure of northern England and the Iapetus suture zone from BIRPS deep seismic reflection profiles. Journal of the Geological Society, London 145, 727–40.CrossRefGoogle Scholar
Glazner, A. F., Bartley, J. M., Coleman, D. S. & Taylor, R. Z. 2004. Are plutons assembled over millions of years by amalgamation from small magma chambers? GSA Today 14, 4–11.2.0.CO;2>CrossRefGoogle Scholar
Grantham, D. R. 1928. The petrology of the Shap granite. Proceedings of the Geologists Association 39, 299–331.CrossRefGoogle Scholar
Grogan, S. E. & Reavy, R. J. 2002. Disequilibrium textures in the Leinster Granite Complex, SE Ireland: evidence for acid-acid mixing. Mineralogical Magazine 66, 929–39.CrossRefGoogle Scholar
Hall, J., Brown, J. A., Mathews, D. H. & Warnėr, M. R. 1984. Crustal structure across the Caledonides from the WINCH seismic reflection profile: influence on the evolution of the Midland Valley of Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences 75, 97–109.CrossRefGoogle Scholar
Halliday, A. N. 1984. Coupled Sm–Nd and U–Pb systematics in late Caledonian granites and the basement under Northern Britain. Nature 307, 229–33.CrossRefGoogle Scholar
Halliday, A. N., Stephens, W. E. & Harmon, R. S. 1980. Rb–Sr and O isotopic relationships in three zoned Caledonian granitic plutons, Southern Uplands, Scotland: evidence for varied sources and hybridisation in magmas. Journal of the Geological Society, London 137, 329–48.CrossRefGoogle Scholar
Harker, A. 1909. Natural History of Igneous Rocks. London: Methuen & Co., 384 pp.Google Scholar
Harmon, R. S. & Halliday, A. N. 1980. Oxygen and strontium isotopic relationships in the late Caledonian granites. Nature 283, 21–5.CrossRefGoogle Scholar
Harmon, R. S., Halliday, A. N., Clayburn, J. A. P. & Stephens, W. E. 1984. Chemical and isotopic systematics of the Caledonian intrusions of Scotland and northern England: a guide to magma source region and magma-crust interaction. Philosophical Transactions of the Royal Society of London A 310 1514, 709–42.Google Scholar
Harry, D. L. & Leeman, W. P. 1995. Partial melting of melt metasomatised subcontinental mantle and the magma source potential of the lower lithosphere. Journal of Geophysical Research 100, 10255–69.CrossRefGoogle Scholar
Highton, A. J. 1999. Late Silurian and Devonian granitic intrusions of Scotland. In Caledonian Igneous Rocks of Britain (eds Stephenson, D., Bevins, R. E., Millward, D., Highton, A. J., Parsons, I., Stone, P. & Wadsworth, W. J.), pp. 397–404. Geological Conservation Review Series: Joint Nature Conservation Committee.Google Scholar
Hirose, K. & Kawamoto, T. 1995. Hydrous partial melting of lherzolite at 1GPa: the effect of H2O on the genesis of basaltic magmas. Earth and Planetary Science Letters 133, 463–73.CrossRefGoogle Scholar
Holden, P., Halliday, A. N. & Stephens, W. E. 1987. Neodymium and strontium isotope content of microdiorite enclaves point to mantle input to granitoid production. Nature 330, 53–6.CrossRefGoogle Scholar
Holden, P., Halliday, A. N., Stephens, W. E. & Henney, P. J. 1991. Chemical and isotopic evidence for major mass transfer between mafic enclaves and felsic magma. Chemical Geology 92, 135–52.CrossRefGoogle Scholar
Holland, J. G. & Lambert, R. S. 1970. Weardale Granite. In Geology of Durham County (ed. Johnson, G. A. L.), pp. 103–18. Transactions of the Natural History Society of Northumberland 41.Google Scholar
Johannes, W. & Holtz, F. 1990. Formation and composition of H2O under saturated melts. In High-temperature Metamorphism and Crustal Anatexis (eds Ashworth, J. R. & Brown, M.), pp. 87–104. London: Unwin Hyman.CrossRefGoogle Scholar
Kemp, A. E. S. 1987. Evolution of Silurian depositional systems in the Southern Uplands, Scotland. In Marine Clastic Sedimentology (eds Leggett, J. K. & Zuffa, G. G.), pp. 124–55. Graham & Trotman.CrossRefGoogle Scholar
Kneller, B. C. 1991. A foreland basin on the southern margin of the Iapetus. Journal of the Geological Society, London 148, 207–10.CrossRefGoogle Scholar
Kneller, B. C., King, L. M. & Bell, A. M. 1993. Foreland basin development and tectonics on the northwest margin of eastern Avalonia. Geological Magazine 130, 691–7.CrossRefGoogle Scholar
Klemperer, S. L., Ryan, P. D. & Snyder, D. B. 1991. A deep seismic reflection transect across the Irish Caledonides. Journal of the Geological Society, London 148, 149–64.CrossRefGoogle Scholar
Kokelaar, B. P. 1988. Tectonic controls of Ordovician arc and marginal basin volcanism in Wales. Journal of the Geological Society, London 145, 759–75.CrossRefGoogle Scholar
Lee, M. R. & Parsons, I. 1997. Compositional and microtextural zoning in alkali feldspars from the Shap granite and its geochemical implications. Journal of the Geological Society, London 154, 183–8.CrossRefGoogle Scholar
Legget, J. K., McKerrow, W. S. & Soper, N. J. 1983. A model for the crustal evolution of southern Scotland. Tectonics 2, 187–210.CrossRefGoogle Scholar
MacDonald, R., Rock, N. M. S., Rundle, C. C. & Russell, O. J. 1986. Relationships between late Caledonian lamprophyric, syenitic, and granitic magmas in a differentiated dyke, southern Scotland. Mineralogical Magazine 50, 547–57.CrossRefGoogle Scholar
MacDonald, R., Thorpe, R. S., Gaskarth, J. W. & Grindrod, A. R. 1985. Multi-component origin of Caledonian lamprophyres of northern England. Mineralogical Magazine 49, 485–94.CrossRefGoogle Scholar
McArdle, P. & Kennedy, M. J. 1987. The East Carlow deformation zone and its regional implications. Geological Survey of Ireland Bulletin 3, 237–55.Google Scholar
McConnell, B. 2000. The Ordovician volcanic arc and marginal basin of Leinster. Irish Journal of Earth Sciences 18, 41–9.Google Scholar
McConnell, B., Philcox, M. E., Sleeman, A. G., Stanley, G., Flegg, A. M., Daly, E. P. & Warren, W. P. 1994. A geological description to accompany the bedrock geology 1:100,000 map series, Sheet 16, Kildare-Wicklow. Geological Survey of Ireland, 70 pp.Google Scholar
McKenzie, D. 1989. Some remarks on the movement of small melt fractions in the mantle. Earth and Planetary Science Letters 95, 53–72.CrossRefGoogle Scholar
Meighan, I. G., Hamilton, M. A., Gamble, J. A., Ellam, R. M. & Cooper, M. R. 2003. The Caledonian Newry complex, NE Ireland: new U–Pb ages, a subsurface extension and magmatic epidote. Joint Meeting: Geological Society of America – Northeastern Section – Atlantic Geoscience Society, March 27–29, 2003, pp. 79. Halifax, Nova Scotia.Google Scholar
Menuge, J. F., Williams, D. M. & O'Connor, P. D. 1995. Silurian turbidites used to reconstruct a volcanic terrain and its Mesoproterozoic basement in the Irish Caledonides. Journal of the Geological Society, London 152, 269–78.CrossRefGoogle Scholar
Merriman, R. J. 2002. Contrasting clay mineral assemblages in British Lower Palaeozoic slate belts: the influence of geotectonic setting. Clay Minerals 37, 207–19.CrossRefGoogle Scholar
Merriman, R. J., Rex, D. C., Soper, N. J. & Peacock, D. R. 1995. The age of Acadian cleavage in northern England, UK: K–Ar and TEM analysis of a Silurian metabentonite. Proceedings of the Yorkshire Geological Society 50, 255–65.CrossRefGoogle Scholar
Millward, D. 2002. Early Palaeozoic magmatism in the English Lake District. Proceedings of the Yorkshire Geological Society 54, 65–93.CrossRefGoogle Scholar
Millward, D, & Evans, J. A. 2003. U–Pb chronology and duration of late-Ordovician magmatism in the English Lake District. Journal of the Geological Society, London 160, 773–81.CrossRefGoogle Scholar
Murphy, B. J. & Keppie, J. D. 2005. The Acadian orogeny in the northern Appalachians. International Geology Review 47, 663–87.CrossRefGoogle Scholar
Nixon, P. H., Rex, D. C. & Condliffe, E. 1984. A note on the age and petrogenesis of lamprophyre dykes of the Cautley area, Yorkshire Dales National Park. Transactions of the Leeds Geological Association 10, 40–5.Google Scholar
O'Connor, P. J., Aftalion, M. & Kennan, P. S. 1989. Isotopic U–Pb ages of zircon and monazite from the Leinster Granite, southeast Ireland. Geological Magazine 126, 725–8.CrossRefGoogle Scholar
Pharaoh, T. C., Morris, J. H., Long, C. B. & Ryan, P. D. 1996. The Tectonic Map of Britain and Ireland (1:1,500,000 map series). British Geological Survey.Google Scholar
Pidgeon, R. T. & Aftalion, M. 1978. Cogenetic and inherited zircons U–Pb systems in granites. Journal of Geology 10, 183–200.Google Scholar
Power, G. M. M. & Barnes, R. P. 1999. Relationships between metamorphism and structure on the northern edge of eastern Avalonia in the Manx Group, Isle of Man. In In sight of the suture: the Palaeozoic geology of the Isle of Man in its Iapetus Ocean context (eds Woodcock, N. H., Quirk, D. G., Fitches, W. R. & Barnes, R. P.), pp. 289–306. Geological Society of London, Special Publication no. 160.Google Scholar
Reavy, R. J. 2001. Caledonian Granites – Emplacement. Open University Geological Society Journal 22, 8–11.Google Scholar
Richmond, L. K. & Williams, B. P. J. 2000. A new terrane in the Old Red Sandstone of the Dingle Peninsula, southwest Ireland. In New Perspectives on the Old Red Sandstone (eds Friend, P. F. & Williams, B. P. J.), pp. 147–83. Geological Society of London, Special Publication no. 180.Google Scholar
Rock, N. M. S., Cooper, C. & Gaskarth, J. W. 1986. Late Caledonian subvolcanic vents and associated dykes in the Kirkudbright area, Galloway, southwest Scotland. Proceedings of the Yorkshire Geological Society 49, 29–37.CrossRefGoogle Scholar
Rock, N. M. S., Gaskarth, J. W. & Rundle, C. C. 1986. Late Caledonian dyke swarms in southern Scotland: a regional zone of primitive K-rich lamprophyres and associated vents. Journal of Geology 94, 505–21.CrossRefGoogle Scholar
Rock, N. M. S., Gaskarth, J. W., Henney, P. J. & Shand, P. 1988. Late Caledonian dyke swarms of northern Britain; some preliminary petrogenetic and tectonic implications of their province-wide distribution and chemical variation. Canadian Mineralogist 26, 3–22.Google Scholar
Rock, N. M. S. & Hunter, R. H. 1987. Late Caledonian dyke swarms of northern Britain: spatial and temporal intimacy between lamprophyric and granite magmatism around the Ross of Mull pluton, Inner Hebrides. Geologische Rundschau 76, 805–26.CrossRefGoogle Scholar
Rundle, C. C. 1992. Review and assessment of isotopic ages from the English Lake District. Technical Report, British Geological Survey WA/92/38, 27 pp.Google Scholar
Ryan, P. D. & Dewey, J. F. 1997. Continental eclogites and the Wilson Cycle. Journal of the Geological Society, London 154, 437–42.CrossRefGoogle Scholar
Ryan, P. D. & Soper, N. J. 2001. Modelling anatexis in intra-cratonic rift basins: an example from the Neoproterozoic of the Scottish Highlands. Geological Magazine 138, 577–88.CrossRefGoogle Scholar
Shand, P., Gaskarth, J. W., Thirwall, M. F. & Rock, N. M. S. 1994. Late Caledonian lamprophyre dyke swarms of south-eastern Scotland. Mineralogy and Petrology 51, 277–98.CrossRefGoogle Scholar
Shepherd, T. J., Beckinsale, R. D., Rundle, C. C. & Durham, J. 1976. Genesis of Carrock Fell tungsten deposits, Cumbria: fluid inclusion and isotopic study. Transactions of the Institution of Mining and Metallurgy 85, B63–73.Google Scholar
Sherlock, S. C., Kelly, S. P., Zalasiewicz, J. A., Scholfield, D. I., Evans, J. A., Merriman, R. J. & Kemp, S. J. 2003. Precise dating of low temperature deformation: strain-fringe analysis by Ar40–Ar39 laser microprobe. Geology 31, 219–22.2.0.CO;2>CrossRefGoogle Scholar
Soper, N. J. 1986. The Newer Granite problem: a geotectonic view. Geological Magazine 123, 227–36.CrossRefGoogle Scholar
Soper, N. J. & Kneller, B. C. 1990. Cleaved microgranite dykes of the Shap swarm in the Silurian of NW England. Geological Journal 25,161–70.CrossRefGoogle Scholar
Soper, N. J. & Roberts, D. E. 1971. Age of cleavage in the Skiddaw Slates in relation to the Skiddaw aureole. Geological Magazine 108, 293–302.CrossRefGoogle Scholar
Soper, N. J., Strachan, R. A., Holdsworth, R. E., Gayer, R. A. & Greiling, R. O. 1992. Sinistral transpression and the closure of Iapetus. Journal of the Geological Society, London 149, 871–80.CrossRefGoogle Scholar
Soper, N. J. & Woodcock, N. 2003. The lost Lower Old Red Sandstone of England and Wales: a record of post Iapetan flexure and Early Devonian transtension. Geological Magazine 140, 627–47.CrossRefGoogle Scholar
Soper, N. J., England, R. W., Snyder, D. B. & Ryan, P. D. 1992. The Iapetan suture in England, Scotland and eastern Avalonia. Journal of the Geological Society, London 149, 697–700.CrossRefGoogle Scholar
Stephens, W. E. 1988. Granitoid plutonism in the Caledonian orogen of Europe. In The Caledonian–Appalachian Orogen (eds Harris, A. L. & Fettes, D. J.), pp. 389–403. Geological Society of London, Special Publication no. 38.Google Scholar
Stephens, W. E. 1992. Spatial, compositional and rheological constraints on the origin of zoning in the Criffel pluton, Scotland. Transactions of the Royal Society of Edinburgh, Earth Sciences 83, 191–9.CrossRefGoogle Scholar
Stephens, W. E. 1999. The Criffel Pluton. In The Caledonian Igneous rocks of Great Britain (eds Stephenson, D., Bevins, R. E., Millward, D., Highton, A. J., Parsons, I., Stone, P. & Wadsworth, W. J.), pp. 460–8. Joint Nature Conservation Committee, Peterborough.Google 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.CrossRefGoogle Scholar
Stephens, W. E., Holden, P. & Henney, P. J. 1991. Microdioritic enclaves within Scottish Caledonian granitoids and their significance for crustal magmatism. In Enclaves and Granite Petrology (eds Didier, J. & Barbarin, B.), pp. 125–34. Developments in Petrology no. 13. Amsterdam: Elsevier.Google Scholar
Stephens, W. E., Whitely, J. E., Thirwall, M. F. & Halliday, A. N. 1985. The Criffel zoned pluton: correlated behaviour of rare earth element abundances with isotopic systems. Contributions to Mineralogy and Petrology 89, 226–38.CrossRefGoogle Scholar
Stephenson, R. E. & Highton, I. 1999. The Caledonian Igneous Rocks of Great Britain: an introduction. In Caledonian Igneous Rocks of Britain (eds Stephenson, D., Bevins, R. E., Millward, D., Highton, A. J., Parsons, I., Stone, P. & Wadsworth, W. J.), pp. 17–19. Geological Conservation Review Series: Joint Nature Conservation Committee.Google Scholar
Stone, P., Kimbell, G. S. & Henney, P. J. 1997. Basement control on the location of strike-slip shear in the Southern Uplands of Scotland. Journal of the Geological Society, London 154, 141–4.CrossRefGoogle Scholar
Thirwall, M. F. 1981. Implications for Caledonian plate tectonic models of chemical data from volcanic rocks of the British Old Red Sandstone. Journal of the Geological Society, London 138, 123–38.CrossRefGoogle Scholar
Thirwall, M. F. 1988. Geochronology of Caledonian magmatism in northern Britain. Journal of the Geological Society, London 145, 951–67.CrossRefGoogle Scholar
Thirwall, M. F. 1989. Movement on proposed terrane boundaries in northern Britain: constraints from Ordovician–Devonian igneous rocks. Journal of the Geological Society, London 146, 373–6.CrossRefGoogle Scholar
Trench, A. & Torsvik, T. H. 1992. The closure of the Iapetus Ocean and Tornquist Sea: new palaeomagnetic constraints. Journal of the Geological Society, London 149, 867–70.CrossRefGoogle Scholar
Vaughan, A. P. M. 1996. A tectonomagmatic model for the genesis and emplacement of Caledonian calc-alkaline lamprophyres. Journal of the Geological Society, London 153, 613–23.CrossRefGoogle Scholar
Wadge, A. J., Gale, N. H., Beckinsale, R. D. & Rundle, C. C. 1978. A Rb–Sr isochron age for the Shap granite. Proceedings of the Yorkshire Geological Society 42, 297–305.CrossRefGoogle Scholar
Wessel, P. & Smith, W. H. F. 1991. Free software helps map and display data. EOS Transactions of the American Geophysical Union 72, 445–6.CrossRefGoogle Scholar
Woodcock, N. 2000. Ordovician volcanism and sedimentation on eastern Avalonia. In Geological History of Britain and Ireland (eds Woodcock, N. H. & Strachan, R. A.), pp. 153–67. Oxford: Blackwell Science.Google Scholar
Wyllie, P. J. 1991. Magmatic consequences of volatile fluxes from the mantle. In Progress in Metamorphic and Magmatic Petrology. Korzhinskii Memorial Volume (ed. Perchuk, L. L.), pp. 477–503. Cambridge University Press.CrossRefGoogle Scholar
Wyllie, P. J. 1995. Experimental petrology of upper mantle materials, processes and products. Journal of Geodynamics 20, 429–68.CrossRefGoogle 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