Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-27T09:27:59.534Z Has data issue: false hasContentIssue false
  • English
  • Français

The Bail Hill Volcanic Group: alkaline within-plate volcanism during Ordovician sedimentation in the Southern Uplands, Scotland

Published online by Cambridge University Press:  03 November 2011

E. R. Phillips ,
R. A. Smith  and
J. D. Floyd
E. R. Phillips
Affiliation:
British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, Scotland, U.K.
R. A. Smith
Affiliation:
British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, Scotland, U.K.
J. D. Floyd
Affiliation:
British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, Scotland, U.K.
Get access Rights & Permissions [Opens in a new window]

Abstract

The Bail Hill Volcanic Group (Caradoc) represents the largest, single volcanic complex exposed within the Ordovician turbidite succession of the Northern Belt in the Southern Uplands of Scotland. The group comprises a heterogeneous sequence of submarine lavas, volcaniclastic and intrusive rocks (up to 2 km thick), and crops out in a small area (c. 4 km2) around Bail Hill, north of Sanquhar. The Cat Cleuch Formation (older) is dominated by a sequence of autobrecciated basaltic lavas which contain large, zoned diopsidic clinopyroxene. The overlying Peat Rig Formation comprises a more mixed sequence of plagioclase-amphibole-phyric lavas, volcaniclastic rocks and contemporaneous volcaniclastic sedimentary rocks. The Cat Cleuch and lower part of the Peat Rig formations are cut by a vent breccia, the Bught Craig vent breccia, which formed part of the feeder to the upper part of the Peat Rig Formation. The Bail Hill volcanic rocks are alkaline in character, ranging from alkali basalt to trachyandesite in composition, possessing trace element characteristics and enrichment patterns typical of oceanic within-plate basalts. The Bail Hill Volcanic Group, although geochemically distinct, forms part of a mixed assemblage of tholeiitic and alkaline withinplate lavas within the Southern Uplands which are of broadly similar age, some of which are intercalated within the greywacke sandstone sequence. This assemblage clearly indicates that a period of extension and within-plate volcanism occurred during the early stages of the development of the Southern Uplands sedimentary basin.

Keywords

alkaline within-plate volcanismOrdovicianSouthern Uplands
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 89 , Issue 4 , 1998 , pp. 233 - 247
Copyright
Copyright © Royal Society of Edinburgh 1998

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

Armstrong, H. A., Owen, A. W., Scrutton, C. T., Clarkson, E. N. K. & Taylor, C. M. 1996. Evolution of the Northern Belt, Southern Uplands: implications for the Southern Uplands controversy. Journal of the Geological Society, London 153, 197–205.Google Scholar
Barnes, R. P., Phillips, E. R. & Merriman, R. J. 1996. Allochthonous Ordovician basaltic rocks of possible island arc affinity in the Southern Uplands, SW Scotland. In Hibbard, J. P., van Staal, C. R. & Cawood, P. A. (eds) New Perspectives in the Appalachian-Caledonian Orogen, Geological Association of Canada, Special Paper 41.Google Scholar
Churkin, M., Carter, C. & Johnson, B. R. 1977. Subdivision of Ordovician and Silurian time scale using accumulation rates of graptolite shale. Geology 5, 452–6.2.0.CO;2>CrossRefGoogle Scholar
Coish, R. A. & Taylor, L. A. 1979. The effects of cooling rate on texture and pyroxene chemistry in DSDP LEG 34 basalt: a microprobe study. Earth & Planetary Science Letters 42, 389–98.Google Scholar
Eyles, V. A. (In Pringle) 1948. British regional geology: The South of Scotland (2nd edition, revised). Edinburgh: HMSO.Google Scholar
Floyd, J. D. 1996. Lithostratigraphy of the Ordovician rocks in the Southern Uplands: Crawford Group, Moffat Shale Group, Leadhills Supergroup. Transactions of the Royal Society of Edinburgh: Earth Sciences 86, 153–65.CrossRefGoogle Scholar
Geikie, A., Peach, B. N., Jack, R. L., Skae, H. & Home, J. 1871. Explanation of Sheet 15. Dumfriesshire (North-west part); Lanarkshire (South part); Ayrshire (South-east part). Memoir of the British Geological Survey of Great Britain.Google Scholar
Harris, P. M., Farrar, E., Maclntyre, R. M., York, D. & Miller, J. A. 1965. Potassium-argon age measurements on two igneous rocks from the Ordovician system of Scotland. Nature, London 205, 352–3.Google Scholar
Hepworth, B. C, Oliver, G. J. H. & McMurtry, M. J. 1982. Sedimentology, volcanism, structure and metamorphism of the northern margin of a Lower Palaeozoic accretionary complex; Bail Hill-Abingdon area of the Southern Uplands of Scotland. In Leggett, J. K. (ed.) Trench-forearc geology, Geological Society of London Special Publication 10.Google Scholar
Kennedy, W. Q. 1936. An apatite-rock from Dumfriesshire. Summary of progress of the Geological Survey of Great Britain for 1935, Part 2, 53–9.Google Scholar
Lambert, R. St. J., Holland, J. G. & Leggett, J. K. 1981. Petrology and tectonic setting of some Ordovician volcanic rocks from the Southern Uplands of Scotland. Journal of the GeologicalSociety, London 136, 755–70.Google Scholar
Leake, B. E. 1978. Nomenclature of amphiboles. Mineralogical Magazine 42, 533–63.CrossRefGoogle Scholar
Leggett, J. K., McKerrow, W. S. & Eales, M. H. 1979. The Southern Uplands of Scotland: a Lower Palaeozoic accretionary prism. Journal of the Geological Society, London 136, 755–70.CrossRefGoogle Scholar
Leterrier, J., Maury, R. C, Thonon, P., Girard, D. & Marchal, M. 1982. Clinopyroxene composition as a method of identification of the magmatic affinities of palaeovolcanic series. Earth and Planetary Science Letters 59, 139–54.Google Scholar
McKerrow, W. S., Leggett, J. K. & Eales, M. H. 1977. Imbricate thrust model of the Southern Uplands of Scotland. Nature 267, 237–9.CrossRefGoogle Scholar
McMurtry, M. J. 1980. Ordovician rocks of the Bail Hill area, Sanquhar, South Scotland: Volcanism and sedimentation in the lapetus Ocean (Unpublished Ph.D. Thesis, University of St. Andrews).Google Scholar
Merriman, R. J., Bevins, R. E. & Ball, T. K. 1987. Petrological and geochemical variation in the Tal y Fan intrusion: a study of element mobility during low-grade metamorphism with implications forpetrogenetic modelling. Journal of Petrology 27, 237–9.Google Scholar
Meschede, M. 1986. A method of discriminating between different types of mid-ocean ridge basalts and continental tholeiites with the Nb-Zr-Y diagram. Chemical Geology 56, 207–18.CrossRefGoogle Scholar
Murphy, F. C. & Hutton, D. H. W. 1986. Is the Southern Uplands really an accretionaryprism? Geology 14, 354–7.Google Scholar
Nisbet, E. G. & Pearce, J. A. 1977. Clinopyroxene composition in mafic lavas from difTerent tectonic settings. Contributions to Mineralogy and Petrology 63, 149–60.CrossRefGoogle Scholar
Odin, G. S. 1986. Recent advances in Phanerozoic time-scale calibration. In Odin, G. S., Calibration of the Phanerozoic Time Scale. Chemical Geology (Isotope Geoscience Section) 59, 103–10.Google Scholar
Peach, B. N. & Home, J. 1899. The Silurian rocks of Britain. Volume 1. Scotland. Memoirs of the Geological Survey of theUnited Kingdom.Google Scholar
Pearce, J. A. 1982. Trace element characteristics of lavas from destructive plate boundaries. In Thorpe, R. S. (ed.) Andesites, 525–48. Chichester: John Wiley.Google Scholar
Pearce, J. A. 1983. Role of the sub-continental lithosphere in magma genesis at active continental margins. In Hawkesworth, C. J. & Norry, M. J. (eds) Continental basalts and mantle xenoliths, 230–49. Nantwich: Shiva.Google Scholar
Pearce, J. A. & Cann, J. R. 1973. Tectonic setting of basic volcanic rocks determinedusing trace element analyses. Earth and Planetary Science Letters 19, 290–300.CrossRefGoogle Scholar
Phillips, E. R., Barnes, R. P., Merriman, R. J. & Floyd, J. D. 1995. The tectonic significance of Ordovician basaltic rocks in the Southern Uplands, SW Scotland. Geological Magazine 132, 549–56.CrossRefGoogle Scholar
Pringle, J. 1948. British Regional Geology: The South of Scotland (Second edition, revised). Edinburgh: HMSO.Google Scholar
Scott, A. 1914. Augite from Bail Hill, Dumfriesshire. Mineralogical Magazine 17, 100–10.CrossRefGoogle Scholar
Shervais, J. W. 1982. Ti-V plots and the petrogenesis of modern and ophiolitic lavas. Earth and Planetary Science Letters 59, 101–18.CrossRefGoogle Scholar
Stone, P., Floyd, J. D., Barnes, R. P. & Lintern, B. C. 1987. A sequential back-arc and foreland basin thrust duplex model for the Southern Uplands of Scotland. Journal of the Geological Society, London 144, 753–64.Google Scholar
Styles, M. T., Stone, P. & Floyd, J. D. 1989. Short Paper: arc detritus in the Southern Uplands; mineralogical characterisation of a ‘missing’ terrane. Journal of the Geological Society, London 146, 397–400.CrossRefGoogle Scholar
Styles, M. T., Perez-Alverez, M. & Floyd, J. D. 1995. Pyroxenous greywackes in the Southern Uplands of Scotland and their petrotectonic implications. Geological Magazine 132, 539–47.Google Scholar
Thirlwall, M. F. 1981. Peralkaline rhyolites from the Ordovician Tweeddale lavas, Peebleshire, Scotland. Geological Journal 16, 41–4.CrossRefGoogle Scholar
Wilson, M. 1989. Igneous petrogenesis: a global tectonic approach. London: Unwin Hyman.CrossRefGoogle Scholar
Winchester, J. A. & Floyd, P. A. 1977. Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chemical Geology 20, 325–43.Google Scholar