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Ashgill greywackes in the Southern Uplands of Scotland: an extension of the Ordovician succession in the Northern Belt

  • J. D. Floyd (a1) and A. W. A. Rushton (a2)

Abstract

In the Southern Uplands of Scotland, the youngest greywackes along the SE margin of the Northern Belt are shown to be of Ashgill age. Mudstones interbedded with the dominantly quartzose greywackes of the Shinnel Formation have yielded Dicellograptus anceps, indicating the anceps Biozone. In addition, the newly-defined mafic-rich Glenlee Formation, lying to the SE of the Shinnel Formation in the New Galloway-Moniaive area, has yielded fossils of the pacificus Subzone, the upper subzone of the anceps Biozone. Since the oldest greywackes of the Central Belt, separated from the Northern Belt by the Orlock Bridge Fault, are now confirmed as of basal Silurian acuminatus Biozone age, the stratigraphical break across the Orlock Bridge Fault is greatly reduced, lending support to the ‘single terrane’ model for the Southern Uplands.

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Anderson, T. B. & Oliver, J. G. H. 1986. The Orlock Bridge Fault: a major Late Caledonian sinistral fault in the Southern Uplands terrane, British Isles. TRANS R SOC EDINBURGH: EARTH SCI 77, 203–22.
Anderson, T. B. & Oliver, J. G. H. 1987. Reply to “Constraints on the significance of the Orlock Bridge Fault within the Scottish Southern Uplands”, a discussion of “The Orlock Bridge Fault: a major Late Caledonian sinistral fault in the Southern Uplands terrane, British Isles”. TRANS R SOC EDINBURGH: EARTH SCI 78, 223–5.
British Geological Survey 1992. Kirkcowan, Scotland. Sheet 4(W). Solid. 1:50000. Southampton: Ordnance Survey for British Geological Survey.
Eckford, R. J. A. & Ritchie, M. 1931. The lavas of Tweeddale and their position in the Caradocian sequence. SUMM PROGR GEOL SURV FOR 1930, Part 3, 4657.
Floyd, J. D. 1982. Stratigraphy of a flysch succession: the Ordovician of West Nithsdale, SW Scotland. TRANS R SOC EDINBURGH: EARTH SCI 73, 19.
Floyd, I. D., Stone, P., Barnes, R. P. & Lintern, B. C. 1987. Constraints on the significance of the Orlock Bridge Fault within the Scottish Southern Uplands, a discussion of “The Orlock Bridge Fault: a major Late Caledonian sinistral fault in the Southern Uplands terrane, British Isles”. TRANS R SOC EDINBURGH: EARTH SCI 78, 219–21.
Kelling, G., Davies, P. & Holroyd, I. 1987. Style, scale and significance of sand bodies in the Northern and Central Belts, southwest Southern Uplands. J GEOL SOC LONDON 144, 787805.
Lapworth, C. 1899. [Review of] The Survey Memoir on the Scottish Uplands. GEOL MAG decade 4 vol. 6, 472-79, 510–20.
Leggett, J. K. 1980a. The sedimentological evolution of a Lower Palaeozoic accretionary fore-arc in the Southern Uplands of Scotland. SEDIMENTOLOGY 27, 401–17.
Leggett, I. K. 1980b. Paleogeographic setting of the Wrae Limestone: an Ordovician submarine-slide deposit in Tweed-dale. SCOTT J GEOL 16, 91104.
Lintern, B. C., Barnes, R. P. & Stone, P. 1992. Discussion on Silurian and Early Devonian sinistral deformation of the Ratagain Granite, Scotland: constraints on the age of Caledonian movements on the Great Glen system, Hutton, D. W. H. & McErlean, M. (1991). J GEOL SOC LONDON 149, 858.
McAdam, A. D. & Tulloch, W. 1985. Geology of the Haddington District. Sheet 33W and part of 41, Scotland. MEM BR GEOL SURV, 99 pp.
McKerrow, W. S., Leggett, J. K. & Eales, M. H. 1977. Imbricate thrust model of the Southern Uplands of Scotland. NATURE 267, 237–9.
McKerrow, W. S., Dewey, J. F. & Scotese, C. R. 1991. The Ordovician and Silurian development of the Iapetus Ocean. SPEC PAP PALAEONT 44, 165–78.
Peach, B. N. & Horne, J. 1899. The Silurian Rocks of Britain, vol. 1. Scotland. MEM GEOL SURV, 749 pp.
Phillips, E. 1992. Microfabric analysis of a series of sheared metasandstones exposed within the Moniaive Shear Zone, Southern Uplands, Scotland. BR GEOL SURV TECH REP WH/92/45, 78 pp.
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. J GEOL SOC LONDON 144, 753–64.
Stone, P. (in press) Geology of the Rhins of Galloway district. Sheets 1 & 3, Scotland. MEM BR GEOL SURV.
Styles, M. T., Stone, P. & Floyd, J. D. 1989. Arc detritus in the Southern Uplands: mineralogical characterisation of a ‘missing’ terrane. J GEOL SOC LONDON 146, 397400.
White, D. E., Barron, H. F., Barnes, R. P. and Lintern, B. C. 1992. Biostratigraphy of late Llandovery (Telychian) and Wenlock turbiditic sequences in the SW Southern Uplands, Scotland. TRANS R SOC EDINBURGH: EARTH SCI 82, 297322.
Williams, S. H. 1982a. Upper Ordovician graptolites from the top lower Hartfell Shale Formation (D. clingani and P. linearis Zones) near Moffat, southern Scotland. TRANS R SOC EDINBURGH: EARTH SCI 72, 229–55.
Williams, S. H. 1982b. The Late Ordovician graptolitic fauna of the Anceps Bands at Dob's Linn, southern Scotland. GEOL ET PALEONTOL 16, 2956.

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Ashgill greywackes in the Southern Uplands of Scotland: an extension of the Ordovician succession in the Northern Belt

  • J. D. Floyd (a1) and A. W. A. Rushton (a2)

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