Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-23T07:47:12.809Z Has data issue: false hasContentIssue false
  • English
  • Français

Sedimentation and tectonism in the Middle Ordovician of the Girvan district, SW Scotland

Published online by Cambridge University Press:  03 November 2011

David Ince
David Ince
Affiliation:
Grant Institute of Geology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, Scotland.
Get access Rights & Permissions [Opens in a new window]

Abstract

The Kirkland Conglomerate and the Benan Conglomerate and associated sediments of the Barr Group (Ordovician—Llanvirn-Llandeilo) of the Girvan district, SW Scotland record the development of two fan-delta systems situated on the northern margin of Iapetus. The intervening Stinchar Limestone represents a shallow marine fan-delta abandonment facies. Subaerial fan-delta deposits are seen at the lowest exposed horizons within the Kirkland Conglomerate. Transgression and eventual abandonment of the fan-delta system is recorded by (1) matrix-rich gravels forming the topmost horizons of the unit. (2) subaqueous distributary channel sands of the overlying transitional sandstone and associated shallow-marine carbonates of the Auchensoul Limestone and (3) shallow-marine sandstones of the Confinis Flags. Following a period of shallow-water sedimentation (Stinchar Limestone), a phase of rapid subsidence occurred during the upper Llandeilo, broadly synchronous with the Nemagraptus gracilis Zone transgression. Lowermost horizons of the succeeding Benan Conglomerate comprise re-sedimented gravels and laterally equivalent ‘outer shelf’ deposits (Superstes Mudstone). Renewal of coarse clastic sedimentation resulted from source area uplift related to granite plutonism, responsible also for the rapid subsidence of basinal areas. Fan-delta progradation is recorded by the occurrence of braided-fluvial deposits and shallow-marine carbonates at higher stratigraphical levels within the unit. Progradation of the fan-delta complex resulted from a gradual reduction in subsidence rates along basin-margin faults.

Fan-deltas of the Barr Group prograded southwards, from a SW—NE-trending faultdelineated basin margin, across a narrow shelf area. To the S of the shelf area defined by Barr Group outcrop, sediments of the Tappins complex accumulated in outer shelf, ?slope and base of slope settings.

The thickness of individual conglomerate units (>150 m—Kirkland Conglomerate, and up to 700 m—Benan Conglomerate), the associated high sedimentation rates, narrowness of the shelf area, and distribution and style of basin-margin faults indicate that oblique-slip motion along the northern margin of Iapetus may have provided a major control over Middle Ordovician sedimentation in the Girvan district.

Keywords

Barr Groupcontinental marginfan-deltaIapetusLlandeiloLlanvirnoblique-slipStinchar Valleysubmarine fanTappins complex
Type
Midland Valley
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 75 , Issue 2: Deep Geology of the Midland Valley of Scotland and Adjacent Regions. Bicentenary Symposium , 1984 , pp. 225 - 237
Copyright
Copyright © Royal Society of Edinburgh 1984

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

Aftalion, M., van Breeman, D. & Bowes, D. R. 1984. Age constraints on basement of the Midland Valley of Scotland. TRANS R SOC EDINBURGH SCI 75, 53–64.CrossRefGoogle Scholar
Anderton, R., Bridges, P., Leeder, M. & Sellwood, B. 1979. A dynamic stratigraphy of the British Isles. London: George Allen & Unwin.Google Scholar
Barret, T. J., Jenkyns, H. C., Leggett, J. K. & Robertson, A. H. F. 1982. Comment: Age and origin of Ballantrae Ophiolite and its significance to the Caledonian orogeny and Ordovician time scale GEOLOGY 10, 331.2.0.CO;2>CrossRefGoogle Scholar
Blissenbach, E. 1954. Geology of alluvial fans in arid regions. BULL GEOL SOC AM 65, 175–90.CrossRefGoogle Scholar
Bluck, B. J. 1969. Old Red Sandstone and other Palaeozoic conglomerates of Scotland. In Kay, M. (ed.) North Atlantic geology and continental drift—a symposium, 711–23. MEM AM ASSOC PETROL GEOL 12.Google Scholar
Bluck, B. J. 1984. Pre-Carboniferous history of the Midland Valley of Scotland. TRANS R SOC EDINBURGH EARTH SCI 75, 275–95.CrossRefGoogle Scholar
Boothroyd, J. C. & Ashley, G. M. 1975. Process, bar morphology and sedimentary structures on braided outwash fans, northeastern Gulf of Alaska. In Jopling, A. V. & McDonald, B. C. (eds) Glaciofluvial and glacio-lacustrine sedimentation, 193–222. SOC ECON PALAEONTOL MINERAL SPEC PUBL 23.CrossRefGoogle Scholar
Boothroyd, J. C. & Nummedal, D. 1978. Proglacial braided outwash: a model for humid alluvial fan deposits. In Miall, A. D. (ed.) Fluvial Sedimentology, 641–68. MEM CAN SOC PETROL GEOL 5.Google Scholar
Church, W. R. & Gayer, R. A. 1973. The Ballantrae ophiolite. GEOL MAG 110, 497–510.CrossRefGoogle Scholar
Clifton, H. E. 1973. Pebble segregation and bed lenticularity in wave worked versus alluvial gravel. SEDIMENTOLOGY 26, 173–87.CrossRefGoogle Scholar
Daily, B., Moore, P. S. & Rust, B. R. 1980. Terrestrial-marine transition in the Cambrian rocks of Kangaroo Island, South Australia. SEDIMENTOLOGY 27, 379–99.CrossRefGoogle Scholar
Davies, I. C. & Walker, R. G. 1974. Transport and deposition of resedimented conglomerates: the Cap Enrage Formation, Cambro-Ordovician, Gaspe, Quebec. J SEDIMENT PETROL 44, 1200–16.Google Scholar
Dewey, J. F. 1971. A model for the Lower Palaeozoic evolution of the Southern margin of the Early Caledonides of Scotland and Ireland. SCOTT J GEOL 7, 219–40.CrossRefGoogle Scholar
Dewey, J. F. 1982. Plate tectonics and the evolution of the British Isles. J GEOL SOC LONDON 139, 371–412.CrossRefGoogle Scholar
Dobkins, J. E. & Folk, R. L. 1970. Shape development on Tahiti-Nui. J SEDIMENT PETROL 40, 1167–203.Google Scholar
Fortey, R. A. 1975. Early Ordovician trilobite communities. FOSSILS STRATA 4, 339–60.CrossRefGoogle Scholar
Graham, A. M. and Upton, B. G. J. 1978. Gneisses in diatremes, Scottish Midland Valley: petrology and tectonic implications. J GEOL SOC LONDON 135, 219–28.CrossRefGoogle Scholar
Gvirtzman, G. and Buchbinder, B. 1978. Recent and Pleistocene coral reefs and coastal sediments of the Gulf of Elat. INT CONGR SEDIMENT Jerusalem, 1978, 161–91.Google Scholar
Hayward, A. B. 1982. Tertiary ophiolite related sedimentation in S.W. Turkey. Unpublished Ph.D. Thesis, Edinburgh University.Google Scholar
Hempton, M. R., Dunn, L. A. and Dewey, J. F. 1983. Sedimentation in an active strike-slip basin, Southeastern Turkey. J GEOL 91, 401–12.CrossRefGoogle Scholar
Holland, C. H., Audley-Charles, M. G., Bassett, M. G., Cowie, J. W., Curry, D., Fitch, F. J., Hancock, J. M., House, M. R., Ingham, J. K., Kent, P. E., Morton, N., Ramsbottom, W. H. C., Rawson, P. F., Smith, D. B., Stubblefield, C. J., Torrens, H. S., Wallace, P. & Woodland, A. W. 1978. A guide to stratigraphical procedure. SPEC REP GEOL SOC LONDON 10.Google Scholar
Ince, D. M. 1983. Shallow-water facies and environments in the Middle Ordovician of the Girvan area, Strathclyde. Unpublished Ph.D Thesis, Edinburgh University.Google Scholar
Ingham, J. K. 1978. Geology of a continental margin, 2: middle and late Ordovician transgression, Girvan. In Bowes, D. R. & Leake, B. E. (eds) Crustal evolution in northwestern Britain and adjacent areas, 163–176. GEOL J SPEC ISSUE 10.Google Scholar
Karig, D. E. 1982. Initiation of subduction zones: implications for arc evolution and ophiolite development. In Leggett, J. K. (ed.) Trench-Forearc Geology: Sedimentation and Tectonism on Modern and Active Plate Margins, 563–76. SPEC PUBL GEOL SOC LONDON 10.Google Scholar
Kelling, G. 1962. The petrology and sedimentation of the Upper Ordovician rocks of the Rhinns of Galloway, southwest Scotland. TRANS R SOC EDINBURGH 65, 107–37.CrossRefGoogle Scholar
Keunen, P. H. 1953. Graded bedding with observations on the Lower Palaeozoic rocks of Britain. VERH K NED AKAD WET AFD NAT 20, 1–17.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. J GEOL SOC LONDON 138, 421–36.CrossRefGoogle Scholar
Lamont, A. & Lindstrom, M. 1957. Arenigian and Llandelian cherts identified in the Southern Uplands by means of conodonts, etc. TRANS EDINBURGH GEOL SOC 17, 60–70.CrossRefGoogle Scholar
Lapworth, C. 1882. The Girvan Succession. Q J GEOL SOC LONDON 38, 537–666.CrossRefGoogle Scholar
Leggett, J. K. 1980. The sedimentological evolution of a Lower Palaeozoic accretionary fore-arc in the Southern Uplands of Scotland, SEDIMENTOLOGY 27, 401–17.CrossRefGoogle Scholar
Leggett, J. K., McKerrow, W. S. & Casey, D. N. 1982. The anatomy of a Lower Palaeozoic accretionary fore-arc: the Southern Uplands of Scotland. In Leggett, J. K. (ed.) Trench-Forearc Geology: Sedimentation and Tectonics on Modern Active Plate Margins, 495–520. GEOL SOC LONDON SPEC PUBL 10.Google Scholar
Leggett, J. K., McKerrow, W. S. & Eales, M. H. 1979. The Southern Uplands of Scotland: a Lower Palaeozoic accretionary prism. J GEOL SOC LONDON 136, 755–70.CrossRefGoogle 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
Longman, C. D., Bluck, B. J. & van Breemen, O. 1979. Ordovician conglomerates and the evolution of the Midland Valley. NATURE 280, 578–81.CrossRefGoogle Scholar
McKerrow, W. S., Leggett, J. K. & Eales, M. H. 1977. Imbricate thrust model of the Southern Uplands of Scotland. NATURE 267, 237–39.CrossRefGoogle Scholar
Miall, A. D. 1977. A review of the braided-river depositional environment. EARTH SCI REV 13, 1–62.CrossRefGoogle Scholar
Nemec, W., Porebski, S. J. & Steel, R. J. 1980. Texture and structure of resedimented conglomerates: examples from the Ksiaz Formation (Fammenian-Tournaisian) Southwestern Poland. SEDIMENTOLOGY 27, 519–38.CrossRefGoogle Scholar
Peach, B. N. and Horne, J. 1899. The Silurian rocks of Britain. MEM GEOL SURV U K 1.Google Scholar
Phillips, W. E. A., Stillman, C. J. & Murphy, T. 1976. A Caledonian plate tectonic model. J GEOL SOC LONDON 132, 579–609.CrossRefGoogle Scholar
Piper, D. J. W. 1972. Trench sedimentation in the Lower Palaeozoic of the Southern Uplands. SCOTT J GEOL 8, 289–91.CrossRefGoogle Scholar
Reading, H. G. 1982. Sedimentary basins and global tectonics. PROC GEOL ASSOC 93, 321–50.CrossRefGoogle Scholar
Ross, R. J. & Ingham, J. K. 1970. Distribution of the Toquima-Table Head (Middle Ordovician Whiterock) faunal realm in the Northern Hemisphere. BULL GEOL SOC AM 81, 393–408.CrossRefGoogle Scholar
Rust, B. R. 1972. Pebble orientation in fluvial sediments. J SEDIMENT PETROL 42, 384–88.Google Scholar
Scott, K. M. & Gravlee, G. C. 1968. Flood surge of the Rubicon River, California—hydrology, hydraulics and boulder transport. PROF PAP U S GEOL SURV 422–M.Google Scholar
Sneed, F. D. & Folk, R. L. 1958. Pebbles in the Lower Colorado River, Texas—a study in particle morphogenesis. J GEOL 66, 114–50.CrossRefGoogle Scholar
Surlyk, F. 1978. Submarine fan sedimentation along fault scarps on tilted fault blocks. (Jurassic-Cretaceous boundary, East Greenland.) GRONLANDS GEOL UNDERS BULL 128.Google Scholar
Tripp, R. P. 1976. Trilobites from the basal Superstes mudstones (Ordovician) at Aidons Quarry, near Girvan Ayrshire. TRANS R SOC EDINBURGH 69, 369–423.Google Scholar
Upton, B. G. J., Aspen, P. & Hunter, R. H. 1984. Xenoliths and their implications for the deep geology of the Midland Valley of Scotland and adjacent regions. TRANS R SOC EDINBURGH EARTH SCI 75, 65–70.CrossRefGoogle Scholar
Vail, P. R., Mitchum, R. M. & Thompson, S. 1977. Global cycles of relative changes in sea level. In Payton, C. E. (ed.) Seismic Stratigraphy—applications to hydrocarbon exploration, 83–97. AM ASSOC PET GEOL MEM 26.Google Scholar
Vos, R. G. 1981. Sedimentology of an Ordovician fan delta complex, Western Libya. SEDIM GEOL 29, 153–70.CrossRefGoogle Scholar
Walker, R. G. 1978. Turbidites and associated coarse clastic deposits. In Walker, R. G. (ed.) Fades Models, 91–103. GEOSCI CAN REPR SER 1.Google Scholar
Walton, E. K. 1965. The Lower Palaeozoic Rocks. In Craig, G. Y. (ed.) The Geology of Scotland, 161–229. Edinburgh: Oliver & Boyd.Google Scholar
Wescott, W. A. and Ethridge, F. G. 1980. Fan-delta sedimentology and tectonic setting—Yallahs Fan Delta, southeast Jamaica. BULL AM ASSOC PET GEOL 64, 374–99.Google Scholar
Wescott, W. A. & Ethridge, F. G. 1983. Eocene fan delta-submarine fan deposition in the Wagwater Trough, east-central Jamaica. SEDIMENTOLOGY 30, 235–47.CrossRefGoogle Scholar
Williams, A. 1959. A structural history of the Girvan district, southwest Ayrshire. TRANS R SOC EDINBURGH 63, 629–67.CrossRefGoogle Scholar
Williams, A. 1962. The Barr and Lower Ardmillan series (Caradoc) of the Girvan district, southwest Ayrshire, with descriptions of the Brachiopoda. MEM GEOL SOC LONDON 3.Google Scholar
Yardley, B. W. D., Vine, F. J. & Baldwin, C. T. 1982. The plate tectonic setting of NW Britain and Ireland in late Cambrian and early Ordovician times. J GEOL SOC LONDON 139, 455–63.CrossRefGoogle Scholar