Hostname: page-component-7479d7b7d-wxhwt Total loading time: 0 Render date: 2024-07-11T14:43:51.699Z Has data issue: false hasContentIssue false
  • English
  • Français

Structural interpretations of the Southern Uplands Terrane

Published online by Cambridge University Press:  03 November 2011

T. Bernard Anderson
T. Bernard Anderson
Affiliation:
T. Bernard Anderson, Department of Geology, Queen's University, Belfast BT7 INN, Northern Ireland,U.K. email: b.anderson@qub.ac.uk
Get access Rights & Permissions [Opens in a new window]

Abstract

ABSTRACT

Bounded by sutures and demonstrating a unique geological history and structure, the Lower Palaeozoic rocks of the Southern Uplands–Down–Longford form a definitive Caledonian suspect terrane. The geological history of the final closure of Iapetus is encrypted in their structural fabric.

Across the terrane, NW-younging turbidites predominate but graptolites invariably indicate the presence of younger sediments to the SSE. This fundamental Southern Upland paradox is soluble only by recognizing many strike-parallel faults, dividing the terrane into more than thirty tracts, each with its own variant of the stratigraphy and structure, and each having a lateral extent far in excess of what might be expected from the probable mechanical strength of the composing sediments. Structural interpretations of the terrane's unique tectonostratigraphic pattern are critically reviewed and the accretionary prism model, modified by strong sinistral transpression from the late Llandovery onward, is preferred. Transpression was apparently triggered when the converging continents of Laurentia and Avalonia made solid contact, so establishing a mechanically effective coupling of sialic crustal elements beneath and across the closing Iapetus ocean basin.

The geometry of the terrane's internal structural fabric is analysed. Tentative area-balancing calculations indicate a crustal shortening from a basin width of at least 1,000 km to the current terrane width of 75 km. Continuing sinistral transpression was expressed in fault reactivation and the development of a major shear zone. Late Palaeozoic strike-parallel extension produced W-facing half-grabens and the associated rotation may account for the easterly plunge of most fold axes.

Keywords

accretionary prismIapetusLower Palaeozoicsuspect terranetransecting cleavagetranspression
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 91 , Issue 3-4: The Southern Uplands Terrane: Tectonics and Biostratigraphy within the Caledonian Orogen , 2000 , pp. 363 - 373
Copyright
Copyright © Royal Society of Edinburgh 2000

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. 1962. The stratigraphy, sedimentology and structure of the Silurian rocks of the Ards Peninsula, County Down (Unpublished Ph.D. Thesis, University of Liverpool).Google Scholar
Anderson, T. B. 1965. The evidence for the Southern Upland Fault in north-east Ireland. Geological Magazine 102, 383–92.CrossRefGoogle Scholar
Anderson, T. B. 1969. The geometry of a natural orthorhombic system of kink bands. In Baer, A. J. & Norris, D. K. (eds) Proceedings, Conference on research in Tectonics (Kink bands and brittle deformation), Geological Survey of Canada Paper 68–52, 200–28.Google Scholar
Anderson, T. B. 1981. Deformation sequences in the Southern Uplands. Scottish Journal of Geology 17, 78–80.CrossRefGoogle Scholar
Anderson, T. B. 1987. The onset and timing of Caledonian sinistral shear in County Down. Journal of the Geological Society, London 144, 817–25.CrossRefGoogle Scholar
Anderson, T. B., Parnell, J. & Ruffell, A. H. 1995. Influence of basement on the geometry of Permo-Triassic basins in the northwest British Isles. In Boldy, S. A. R. (ed.) Permian and Triassic Rifting in Northwest Europe, Geological Society, London, Special Publication 91, 103–22.CrossRefGoogle Scholar
Anderson, T. B. & Cameron, T. D. J. 1979. A structural profile of Caledonian deformation in Down. In Harris, A. L., Holland, C. H. & Leake, B. E. (eds) The Caledonides of the British Isles—Reviewed, Geological Society, London, Special Publication 8, 263–7.CrossRefGoogle Scholar
Anderson, T. B. & Oliver, G. J. H. 1986. The Orlock Bridge Fault: a major late Caledonian sinistral fault in the Southern Uplands terrane, British Isles. Transactions of the Royal Society of Edinburgh: Earth Sciences 77, 203–22.CrossRefGoogle Scholar
Anderson, T. B. & Oliver, G. J. H. 1996. Xenoliths of Iapetus Suture mylonites in County Down lamprophyres, Northern Ireland. Journal of the Geological Society, London 153, 403–7.CrossRefGoogle Scholar
Anderson, T. B. & Rickards, R. B. 2000. The stratigraphy and graptolite faunas of the Moffat Shales at Tieveshilly, County Down, Northern Ireland and their implications for the modelling of the Southern Uplands–Down–Longford terrane. Irish Journal of Earth Sciences 18, 69–88.Google Scholar
Barnes, R. P. 1989. Geology of the Whithorn district. Memoir of the British Geological Survey Sheet 2 (Scotland). Keyworth, Nottingham: British Geological Survey.Google Scholar
Barnes, R. P., Anderson, T. B. & McCurry, J. A. 1987. Along-strike variation in the stratigraphic and structural profile of the Southern Uplands Central Belt in Galloway and Down. Journal of the Geological Society, London 144, 807–16.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 146, 905–8.CrossRefGoogle Scholar
Barnes, R. P. & Stone, P. 1999. Trans-Iapetus contrasts in the geological development of southern Scotland (Laurentia) and the Lakesman Terrane (Avalonia). In Woodcock, N. H., Quirk, D. G., Fitches, W. R. & Barnes, R. P. (eds) In Sight of the Suture: the Palaeozoic geology of the Isle of Man in its Iapetus Ocean context, Geological Society, London, Special Publication 160, 307–23.Google Scholar
Bluck, B. J. 1983. Role of the Midland Valley of Scotland in the Caledonian orogeny. Transactions of the Royal Society of Edinburgh: Earth Sciences 74, 119–36.CrossRefGoogle Scholar
British Geological Survey 1991. Moffatdale. Solid geology. 1:25,000. Classical areas of British Geology. London: HMSO for British Geological Survey.Google Scholar
British Geological Survey 1992. The Rhins of Galloway, Scotland Sheets 1 and 3 with parts of 7 and 4 W. Solid geology: 1:50,000. Keyworth, Nottingham: British Geological Survey.Google Scholar
Cameron, T. D. J. 1981. The history of Caledonian deformation in East Lecale, County Down. Journal of Earth Sciences: Royal Dublin Society 4, 53–74.Google Scholar
Coney, P. J., Jones, D. L. & Monger, J. W. H. 1980. Cordilleran suspect terranes. Nature 288, 329–33.CrossRefGoogle Scholar
Craig, G. Y. & Walton, E. K. 1959. Sequence and structure in the Silurian rocks of Kirkcudbrightshire. Geological Magazine 96, 209–20.CrossRefGoogle Scholar
Davis, D., Suppe, J. & Dahlen, F. A. 1983. Mechanics of fold-and-thrust belts and accretionary wedges. Journal of Geophysical Research 88, 1153–72.CrossRefGoogle Scholar
Davis, E. E. & Hyndman, R. D. 1989. Accretion and recent deformation of sediments along the northern Cascadia subduction zone. Geological Society of America Bulletin 101, 1465–80.2.3.CO;2>CrossRefGoogle Scholar
Dewey, J. F. 1969. Evolution of the Appalachian/Caledonian orogen. Nature 222, 124–9.CrossRefGoogle Scholar
Dewey, J. F. 1971. A model for the Lower Palaeozoic evolution of the southern margin of the early Caledonides in Scotland and Ireland. Scottish Journal of Geology 7, 219–40.CrossRefGoogle Scholar
Floyd, J. D. 1994. The derivation and definition of the ‘Southern Upland Fault’: a review of the Midland Valley–Southern Uplands terrane boundary. Scottish Journal of Geology 30, 51–62.CrossRefGoogle 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
Floyd, J. D. & Phillips, E. R. 1999. Xenoliths of Southern Uplands ‘basement?’ in a lamprophyre dyke, Central belt, Glenluce, SW Scotland. Scottish Journal of Geology 35, 57–62.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 of magmas. Journal of the Geological Society, London 137, 329–49.CrossRefGoogle Scholar
Harkness, R. 1851. On the Silurian rocks of Dumfriesshire and Kirkcudbrightshire. Quarterly Journal of the Geological Society 7, 46–58.CrossRefGoogle Scholar
Hossack, J. 1979. The use of balanced cross-sections in the calculation of orogenic contraction: A review. Journal of the Geological Society, London 136, 705–11.CrossRefGoogle Scholar
Hutton, D. H. W. 1987. Strike-slip terranes and a model for the evolution of the British and Irish Caledonides. Geological Magazine 124, 405–25.CrossRefGoogle Scholar
Hutton, D. H. W. & McErlean, M. 1991. Silurian and Early Devonian sinistral deformation of the Ratagain granite, Scotland: constraints on the age of Caledonian movements on the Great Glen fault system. Journal of the Geological Society, London 148, 1–4.CrossRefGoogle Scholar
Kelley, S. & Bluck, B. J. 1989. Detrital mineral ages from the Southern Uplands using 40Ar–39Ar laser probe. Journal of the Geological Society, London 146, 401–3.CrossRefGoogle Scholar
Kelley, S. & Bluck, B. J. 1990. Discussion on detrital mineral ages from the Southern Uplands using 40Ar–39Ar laser probe. Journal of the Geological Society, London 147, 882–4.Google Scholar
Kelling, G. 1958. The Ordovician rocks of the Rhinns of Galloway (Unpublished Ph.D. Thesis, University of Edinburgh).CrossRefGoogle Scholar
Kelling, G. 1961. The stratigraphy and structure of the Ordovician rocks of the Rhinns of Galloway. Journal of the Geological Society, London 117, 37–75.CrossRefGoogle Scholar
Kelling, G., Phillips, W. E. A., Harris, A. L. & Howells, M. F. 1985. The Caledonides of the British Isles: A review and appraisal. In Gee, D. G. & Sturt, B. A. (eds) The Caledonide Orogen-Scandinavia and Related Areas, 1125–46. Chichester: Wiley.Google Scholar
Kelling, G., Davies, P. & Holroyd, J. 1987. Style, scale and significance of sand bodies in the Northern and Central Belts, southwest Southern Uplands. Journal of the Geological Society, London 114, 787–805.CrossRefGoogle Scholar
Knipe, R. J. & Needham, D. T. 1986. Deformation processes in accretionary wedges—examples from the SW margin of the Southern Uplands, Scotland. In Coward, M. P. & Rees, A. C. (eds) Collision Tectonics, Geological Society, London, Special Publication 19, 51–65.CrossRefGoogle Scholar
Lapworth, C. 1889. On the Ballantrae rocks of the south of Scotland and their place in the upland sequence. Geological Magazine 6, 20 and 59.CrossRefGoogle Scholar
Leggett, J. K. 1987. The Southern Uplands as an accretionary prism: the importance of analogues in reconstructing palaeogeography. Journal of the Geological Society, London 144, 737–52.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
Leggett, J. K., McKerrow, W. S. & Casey, D. M. 1982. The anatomy of a Lower Palaeozoic accretionary forearc: The Southern Uplands of Scotland. In Leggett, J. K. (ed.) Trench-Forearc Geology, Geological Society, London, Special Publication 10, 494–520.Google Scholar
Leggett, J. K., McKerrow, W. S. & Soper, N. J. 1983. A Model for the Crustal Evolution of Southern Scotland. Tectonics 2, 187–210.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. Journal of the Geological Society, London 149, 858.Google Scholar
McCaffrey, R. 1996. Slip partitioning at convergent plate boundaries of SE Asia. In Hall, R. & Blundell, D. (eds) Tectonic Evolution of Southeast Asia, Geological Society, London, Special Publication 106, 3–18.CrossRefGoogle Scholar
McCurry, J. A. 1989. The geology of the Lower Palaeozoic rocks in the Mull of Galloway, SW Scotland: studies in an imbricate thrust terrane (Unpublished Ph.D. Thesis, University of St. Andrews).Google Scholar
McCurry, J. A. & Anderson, T. B. 1989. Landward vergence in the lower Palaeozoic Southern Uplands–Down–Longford terrane. Geology 17, 630–33.2.3.CO;2>CrossRefGoogle Scholar
McKerrow, W. S. 1987. The Southern Uplands Controversy. Journal of the Geological Society, London 144, 735–6.CrossRefGoogle 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. & Elders, C. F. 1989. Movements on the Southern Upland Fault. Journal of the Geological Society, London 146, 393–5.CrossRefGoogle Scholar
McMillan, A. A. & Brand, P. J. 1995. Depositional setting of Permian and Upper Carboniferous strata of the Thornhill Basin, Dumfriesshire. Scottish Journal of Geology 31, 43–52.CrossRefGoogle Scholar
Merriman, R. J. & Roberts, B. 1990. The low grade metamorphism of Lower Palaeozoic strata on the Rhins of Galloway, SW Scotland. British Geological Survey Technical Report WG/92/40. Keyworth, Nottingham: British Geological Survey.Google Scholar
Mitchell, A. H. G. & McKerrow, W. S. 1975. Analogous evolution of the Burma orogen and the Scottish Caledonides. Geological Society of America Bulletin 86, 305–15.2.0.CO;2>CrossRefGoogle Scholar
Moore, J. C. 1857. On the Silurian rocks of Wigtownshire. Journal of the Geological Society, London 12, 359–66.CrossRefGoogle Scholar
Morris, J. H. 1987. The Northern Belt of the Longford-Down Inlier, Ireland and Southern Uplands, Scotland: an Ordovician back-arc basin. Journal of the Geological Society, London 144, 773–86.CrossRefGoogle Scholar
Murphy, F. C. 1985. Non-axial planar cleavage and Caledonian sinistral transpression in eastern Ireland. Geological Journal 20, 257–79.CrossRefGoogle Scholar
Needham, D. T. 1993. The structure of the western part of the Southern Uplands of Scotland. Journal of the Geological Society, London 150, 341–54.CrossRefGoogle Scholar
Needham, D. T. & Knipe, R. J. 1986. Accretion- and collision-related deformation in the Southern Uplands accretionary wedge. Geology 14, 303–306.2.0.CO;2>CrossRefGoogle Scholar
Needham, T. & Morgan, R. 1997. The East Irish Sea and adjacent basins: new faults or old? Journal of the Geological Society, London 154, 145–50.CrossRefGoogle Scholar
Owen, A. W. & Clarkson, E. N. K. 1992. Trilobites from Kilbucho and Wallace's Cast and the location of the Northern Belt of the Southern Uplands during the late Ordovician. Scottish Journal of Geology 28, 3–17.CrossRefGoogle Scholar
Peach, B. W. & Home, J. 1899. The Silurian Rocks of Britain, Vol. 1.: Scotland. Memoirs of the Geological Survey of the United Kingdom. Glasgow: HMSO.Google Scholar
Phillips, E. R., Barnes, R. P., Boland, M. P., Fortey, N. J. & McMillan, A. A. 1995. The Moniaive Shear Zone: a major zone of sinistral strike-slip deformation in the Southern Uplands of Scotland. Scottish Journal of Geology 31, 139–49.CrossRefGoogle Scholar
Phillips, W. E. A., Stillman, C. J. & Murphy, T. 1976. A Caledonian plate tectonic model. Journal of the Geological Society, London 132, 579–609.CrossRefGoogle Scholar
Platt, J. P. 1990. Thrust mechanics in highly overpressured accretionary wedges. Journal of Geophysical Research 95, 9025–34.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 veins. Journal of Geology 94, 505–22.CrossRefGoogle Scholar
Rushton, A. W. A., Stone, P. & Hughes, R. A. 1996. Biostratigraphical controls of thrust models for the Southern Uplands of Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences 86, 137–52.CrossRefGoogle Scholar
Rust, B. R. 1963. The geology of the area around Whithorn, Wigtownshire (Unpublished Ph.D. Thesis, University of Edinburgh).Google Scholar
Rust, B. R. 1965. The stratigraphy and structure of the Whithorn area of Wigtownshire, Scotland. Scottish Journal of Geology 1, 101–33.CrossRefGoogle Scholar
Sanderson, D. J., Andrews, J. R., Phillips, W. E. A. & Hutton, D. H. W. 1980. Deformation studies in the Irish Caledonides. Journal of the Geological Society, London 137, 289–302.CrossRefGoogle Scholar
Shackleton, R. M. 1986. Precambrian collision tectonics in Africa. In Coward, M. P. & Rees, A. C. (eds) Collision Tectonics, Geological Society of London Special Publication 19, 329–49.CrossRefGoogle Scholar
Soper, N. J., England, R. W., Snyder, D. B. & Ryan, P. D. 1992. The Iapetus suture zone in England, Scotland and eastern Ireland: a reconciliation of geological and deep seismic data. Journal of the Geological Society, London 149, 697–700.CrossRefGoogle Scholar
Stone, P. 1995. Geology of the Rhins of Galloway district. Sheets 1 and 3 (Scotland). Memoir of the British Geological Survey. London: HMSO for British Geological Survey.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. Journal of the Geological Society, London 144, 753–64.CrossRefGoogle Scholar
Stringer, P. & Treagus, J. E. 1980. Non-axial planar S1 cleavage in the Hawick Rocks of the Galloway area, Southern Uplands, Scotland. Journal of Structural Geology 2, 317–31.CrossRefGoogle Scholar
Stringer, P. & Treagus, J. E. 1981. Asymmetrical folding in the Hawick Rocks of the Galloway area, Southern Uplands. Scottish Journal of Geology 17, 129–48.CrossRefGoogle Scholar
Todd, S. P., Murphy, F. C. & Kennan, P. S. 1991. On the trace of the Iapetus suture in Ireland and Britain. Journal of the Geological Society, London 148, 869–80.CrossRefGoogle Scholar
Vrolijk, P. 1990. On the mechanical role of the smectite in subduction zones. Geology 18, 703–707.2.3.CO;2>CrossRefGoogle Scholar
Walton, E. K. & Oliver, G. J. H. 1991. Lower Palaeozoic—Structure and Palaeogeography. In Craig, G. Y. (ed) Geology of Scotland, 3rd edn, 195–228. London: The Geological Society.Google Scholar
Watson, J. V. 1984. The ending of the Caledonian Orogeny in Scotland. Journal of the Geological Society, London 141, 193–214.CrossRefGoogle Scholar
Webb, B. C., Rushton, A. W. A. & White, D. E. 1993. Moffatdale and the Upper Ettrick valley: a description of the solid geology of parts of 1:25,000 sheet NT 10, 11, 20 and 21. Classical areas of British geology. London: HMSO for British Geological Survey.Google Scholar
Weir, J. A. 1968. Structural history of the Silurian rocks of the coast west of Gatehouse, Kirkcudbrightshire. Scottish Journal of Geology 4, 31–52.CrossRefGoogle Scholar
Weir, J. A. 1979. Tectonic contrasts in the Southern Uplands. Scottish Journal of Geology 15, 169–86.CrossRefGoogle Scholar
Welsh, W. 1964. The Ordovician rocks of North-west Wigtownshire (Unpublished Ph.D. Thesis, University of Edinburgh).Google Scholar