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Biostratigraphy of late Llandovery (Telychian) and Wenlock turbiditic sequences in the SW Southern Uplands, Scotland

Published online by Cambridge University Press:  03 November 2011

Dennis E. White
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K.
Hugh F. Barron
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K.
Robert P. Barnes
Affiliation:
British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, U.K.
Byron C. Lintern
Affiliation:
British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, U.K.

Abstract

In the SW part of the Southern Uplands of Scotland the relatively thin Moffat Shale Group (late Ordovician–early Silurian) is succeeded by a thick development of Silurian greywackes, of variable turbiditic facies. This includes late Llandovery (Telychian) quartzose greywackes with interbedded thin graptolitic shales of the turriculatus and crispus biozones, in the upper part of the Gala Group, a sequencewhich is laterally equivalent to the basal part of the Hawick Group. The age of the finer-grained calcareous Hawick Group, which here includes 1. the Ross Formation, ranges from late Llandovery (turriculatus Biozone) to early Wenlock (riccartonensis Biozone). The Riccarton Group, which contains thick units of thinly-bedded siltstones and mudstones, is of Wenlock age (riccartonensis to lundgreni biozones). Within this sequence, all the biozones of the standard graptolite zonal scheme have been recognised in the area, with the exception of the crenulata Biozone of the late Llandovery (Telychian Stage) and the murchisoni and ellesae biozones of the Wenlock (Sheinwoodian Stage). Details of the graptolite biostratigraphy areclosely comparable with those of the markedly thinner sequences of northern England. Acritarchs occur throughout the sequence but are most numerous and best preserved in the Gala Group. Poorly preserved chitinozoa and spores are also present, the former occurring sporadically throughout the succession but the latter become common only in the Riccarton Group.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1991

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References

Barnes, R. P. 1989. Geology of the Whithorn district. MEM BR GEOL SURV Sheet 2, Scotland.Google Scholar
Barnes, R. P., Anderson, T. B. & McCurry, J. A. 1987. Along-strike variation in the stratigraphical and structural profile of the Southern Uplands Central Belt in Galloway and Down. J GEOL SOC 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. J GEOL SOC LONDON 146, 905–8.CrossRefGoogle Scholar
Barron, H. F. 1989. Mid-Wenlock acritarchs from a Silurian inlier in the Cheviot Hills, NE England. SCOTT J GEOL 25, 8198.CrossRefGoogle Scholar
Bjerreskov, M. 1975. Llandoverian and Wenlockian graptolites from Bornholm. FOSSILS AND STRATA 8, 193.CrossRefGoogle Scholar
Burgess, I. C., Rickards, R. B. & Strachan, I. 1970. The Silurian strata of the Cross Fell area. BULL GEOL SURV GB 32, 167–82.Google Scholar
Clarkson, C. M., Craig, G. Y. & Walton, E. K. 1975. The Silurian Rocks bordering Kirkcudbright Bay, South Scotland. TRANS R SOC EDINBURGH 69, 313–25.CrossRefGoogle Scholar
Cocks, L. R. M. & Toghill, P. 1973. The biostratigraphy of the Silurian rocks of the Girvan District, Scotland. J GEOL SOC LONDON 129, 209–43.CrossRefGoogle Scholar
Craig, G. Y. & Walton, E. K. 1959. Sequence and structure in the Silurian rocks of Kirkcudbrightshire. GEOL MAG 96, 209–20.CrossRefGoogle Scholar
Davies, J. R., Fletcher, C. J., Waters, R. A. & Wilson, D. The Geology of the Llanilar and Rhayader districts. MEM BR GEOLSURV Sheets 178 and 179. In preparation.Google Scholar
Dorning, K. J. 1981a. Silurian acritarchs from the type Wenlock and Ludlow of Shropshire, England, REV PALAEOBOT PALYNOL 34, 175203.CrossRefGoogle Scholar
Dorning, K. J. 1981b. Silurian acritarch distribution in the Ludlovian shelf sea of South Wales and the Welsh Borderland. In Neale, J. W. & Brasier, M. D. (eds) Microfossils from Recent and Fossil Shelf Seas, 31–6. Chichester: Ellis Horwood.Google Scholar
Dorning, K. J. 1982. Early Wenlock acritarchs from the Knockgardner and Straiton Grits Formations of Knockgardner, Ayrshire. SCOTT JGEOL 18, 267–73.CrossRefGoogle Scholar
Dorning, K. J. & Bell, D. G. 1987. The Silurian carbonate shelf microflora: acritarch distribution in the Much Wenlock Limestone Formation. In Hart, M. B. (ed.) Micropalaeontology of Carbonate Environments, 266–87. Chichester: Ellis Horwood.Google Scholar
Dorning, K. J. & Hill, P. J. 1991. Silurian stratigraphy and palynology of the Llandovery, Wenlock and Ludlow Series of the type areas in England and Wales. REV PALAEOBOT PALYNOL (in press).Google Scholar
Elles, G. L. & Wood, E. M. R. 1991. A monograph of British graptolites, part 8, 359–414, pls 36–41. MONOGR PALAEONTOGR SOC.Google Scholar
Fensome, R. A., Williams, G. L., Sedley Barss, M., Freeman, J. M. & Hill, J. M. 1990. Acritarchs and fossil prasinophytes: an index to genera, species and infraspecific taxa. AASP Contributions Series No. 25, 771pp.Google Scholar
Gray, J., Laufeld, S. & Boucot, A. J. 1974. Silurian trilete spores and spore tetrads from Gotland: their implications for land plant evolution. SCIENCE 185, 260–3.CrossRefGoogle ScholarPubMed
Greig, D. C. 1971. British Regional Geology: The South of Scotland (3rd edition). Edinburgh: H.M.S.O.Google Scholar
Hill, P. J. 1974. Stratigraphie palynology of acritarchs from the type area of the Llandovery and the Welsh Borderland. REV PALAEOBOT PALYNOL 18, 1123.CrossRefGoogle Scholar
Hill, P. J. & Doming, K. J. 1984. Acritarchs. In Cocks, L. R. M., Woodcock, N. H., Rickards, R. B., Temple, J. T. & Lane, P. D.The Llandovery Series of the type area. BULL BR MUS NAT HIST (GEOL) 38, 174–6.Google Scholar
Hutt, J. E. 1974. The Llandovery graptolites of the English Lake District, part 1, 1–56, pls 1–10. MONOGR PALAEONTOGR SOC.CrossRefGoogle Scholar
Jones, O. T. 1921. The Valentian Series. Q J GEOL SOC LONDON 77, 144–74.CrossRefGoogle Scholar
Kemp, A. E. S. 1986. Tectonostratigraphy of the Southern Belt of the Southern Uplands. SCOTT J GEOL 22, 241–56.CrossRefGoogle Scholar
Kemp, A. E. S. & White, D. E. 1985. Silurian trench sedimentation in the Southern Uplands, Scotland: implications of new age data. GEOL MAG 122, 275–7.CrossRefGoogle Scholar
Lamont, A. 1947. Gala-Tarannon Beds in the Pentland Hills, near Edinburgh. GEOL MAG 84, 319.CrossRefGoogle Scholar
Lapworth, C. 1870. On the Lower Silurian rocks of Galashiels. GEOL MAG 7, 204–9, 279–84.CrossRefGoogle Scholar
Lapworth, C. 1878. The Moffat Series. Q J GEOL SOC LONDON 34, 240346.CrossRefGoogle Scholar
Lapworth, C. 1889. On the Ballantrae rocks of South Scotland and their place in the upland sequence. GEOL MAG 6, 20–4, 59–69.CrossRefGoogle Scholar
Lapworth, C. & Wilson, J. 1871. On the Silurian rocks of the countries of Roxburgh and Selkirk. GEOL MAG 8, 456–64.CrossRefGoogle Scholar
Lumsden, G. I., Tulloch, W., Howells, M. F. & Davies, A. 1967. Geology of the neighbourhood of Langholm. MEM GEOL SURV GB.Google Scholar
Martin, F. 1989. Acritarchs. In Holland, C. H. & Basset, M. G. (eds) A Global Standard for the Silurian System, GeologicalSeries 9, 207–15. Cardiff: National Museum of Wales.Google Scholar
McCaffrey, W. D., Barron, H. F., Molyneux, S. G. & Kneller, B. C.Recycled acritarchs as provenance indicators: Implications for Caledonian terrane reconstruction. GEOL MAG (in press).Google Scholar
Molyneux, S. G. 1987. Probable early Wenlock acritarchs from the Linkim Beds of the Southern Uplands. SCOTT J GEOL 23, 301–13.CrossRefGoogle Scholar
Murchison, R. I. 1851. On the Silurian rocks of the South of Scotland, with a list and description of the Silurian fossils of Ayrshire. By J. W. Salter. Q J GEOL SOC LONDON 7, 137–78.CrossRefGoogle Scholar
Paris, F. 1989. Chitinozoans. In Holland, C. H. & Bassett, M. G. (eds) A Global Standard for the Silurian System, Geological Series 9, 280–83. Cardiff: National Museum of Wales.Google Scholar
Peach, B. N. & Horne, J. 1899. The Silurian rocks ofBritain. 1, Scotland, MEM GEOL SURV UK.Google Scholar
Priewalder, H. 1987. Acritarchen aus dem Silur des Cellon-Profils (Karnische Alpen, Österreich). ABH GEOL BUNDESANST 40, 1121.Google Scholar
Pringle, J. 1948. British Regional Geology: The South of Scotland (2nd edition, revised). Edinburgh: HMSO.Google Scholar
Rickards, R. B. 1965. New Silurian graptolites from the Howgill Fells (Northern England). PALAEONTOL 8, 247–71.Google Scholar
Rickards, R. B. 1967. The Wenlock and Ludlow succession in the Howgill Fells (north-west Yorkshire and Westmoreland). Q J GEOL SOC LONDON 123, 215–49.CrossRefGoogle Scholar
Rickards, R. B. 1969. Wenlock graptolite zones in the English Lake District. PROC GEOL SOC LONDON, No. 1654, 61–5.Google Scholar
Rickards, R. B. 1970. The Llandovery (Silurian) graptolites of the Howgill Fells, Northern England, 1–108, pls 1–8. MONOGR PALAEONTOGR SOC.Google Scholar
Rickards, R. B. 1973. On some highest Llandovery red beds and graptolite assemblages in Britain and Eire. GEOL MAG 110, 70–2.CrossRefGoogle Scholar
Rickards, R. B. 1976. The sequence of Silurian graptolite zones in the British Isles. GEOL J 11, 153–88.CrossRefGoogle Scholar
Rust, B. R. 1965. The stratigraphy and structure of the Whithornarea of Wigtownshire, Scotland. SCOTT J GEOL 1, 101–33.CrossRefGoogle Scholar
Scotese, C. R. & McKerrow, W. S. 1990. Revised Worldmaps and introduction. In McKerrow, W. S. & Scotese, C. R. (eds) Palaeozoic Palaeogeography and Biogeography, Memoir No. 12, Geological Society of London, 121.Google Scholar
Scrutton, C. T. & McCurry, J. A. 1987. The derivation, biostratigraphy and palaeogeographic significance of corals from Silurian deep-sea turbidite facies in the south-west Southern Uplands. SCOTT J GEOL 23, 4964.CrossRefGoogle Scholar
Strachan, I. 1982. The distribution of graptolites in south-east Scotland, with notes on the fauna of Old Cambus Quarry. SCOTT J GEOL 18, 157–65.CrossRefGoogle Scholar
Toghill, P. 1970. The south-east limit of the Moffat Shales in the upper Ettrick Valley region, Selkirkshire. SCOTT J GEOL 6, 233–42.CrossRefGoogle Scholar
Toghill, P. & Strachan, I. 1970. The graptolite fauna of Grieston Quarry, near Innerleithen, Peebleshire. PALAEONTOL 13, 511–21.Google Scholar
Warren, P. T. 1964. The stratigraphy and structure of the Silurian (Wenlock) rocks south-east of Hawick, Roxburghshire, Scotland. Q J GEOL SOC LONDON 120, 193222.CrossRefGoogle Scholar
Webb, B. C., Rushton, A. W. A., & White, D. E.Classical areas of British geology: Moffatdale and the Upper Ettrick Valley: a description of parts of 1:25 000 sheets NT 10, 11, 20 and 21. London: H.M.S.O. (in press).Google Scholar
Zalasiewicz, J. A. 1990. Silurian graptolite biostratigraphy in the Welsh Basin. J GEOL SOC 147, 619–22.CrossRefGoogle Scholar