Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-22T17:30:01.265Z Has data issue: false hasContentIssue false
  • English
  • Français

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

Published online by Cambridge University Press:  03 November 2011

J. D. Floyd  and
A. W. A. Rushton
J. D. Floyd
Affiliation:
J. D. Floyd, British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA
A. W. A. Rushton
Affiliation:
A. W. A. Rushton, British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG
Get access Rights & Permissions [Opens in a new window]

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.

Keywords

Glenlee Formationgraptolitesmafic greywackesOrlock Bridge FaultShinnel Formationterrane
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 84 , Issue 1 , 1993 , pp. 79 - 85
Copyright
Copyright © Royal Society of Edinburgh 1993

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

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.CrossRefGoogle Scholar
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.CrossRefGoogle Scholar
British Geological Survey 1992. Kirkcowan, Scotland. Sheet 4(W). Solid. 1:50000. Southampton: Ordnance Survey for British Geological Survey.Google Scholar
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, 46–57.Google Scholar
Floyd, J. D. 1982. Stratigraphy of a flysch succession: the Ordovician of West Nithsdale, SW Scotland. TRANS R SOC EDINBURGH: EARTH SCI 73, 1–9.CrossRefGoogle Scholar
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.CrossRefGoogle Scholar
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, 787–805.CrossRefGoogle Scholar
Lapworth, C. 1899. [Review of] The Survey Memoir on the Scottish Uplands. GEOL MAG decade 4 vol. 6, 472-79, 510–20.CrossRefGoogle Scholar
Leggett, J. K. 1980a. The sedimentological evolution of a Lower Palaeozoic accretionary fore-arc in the Southern Uplands of Scotland. SEDIMENTOLOGY 27, 401–17.CrossRefGoogle Scholar
Leggett, I. K. 1980b. Paleogeographic setting of the Wrae Limestone: an Ordovician submarine-slide deposit in Tweed-dale. SCOTT J GEOL 16, 91–104.CrossRefGoogle Scholar
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.Google Scholar
McAdam, A. D. & Tulloch, W. 1985. Geology of the Haddington District. Sheet 33W and part of 41, Scotland. MEM BR GEOL SURV, 99 pp.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
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.Google Scholar
Peach, B. N. & Horne, J. 1899. The Silurian Rocks of Britain, vol. 1. Scotland. MEM GEOL SURV, 749 pp.Google Scholar
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.Google 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. J GEOL SOC LONDON 144, 753–64.CrossRefGoogle Scholar
Stone, P. (in press) Geology of the Rhins of Galloway district. Sheets 1 & 3, Scotland. MEM BR GEOL SURV.Google Scholar
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, 397–400.CrossRefGoogle Scholar
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, 297–322.CrossRefGoogle Scholar
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.CrossRefGoogle Scholar
Williams, S. H. 1982b. The Late Ordovician graptolitic fauna of the Anceps Bands at Dob's Linn, southern Scotland. GEOL ET PALEONTOL 16, 29–56.Google Scholar