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Caradoc turbidites at Poppit Sands (Pembrokeshire), Wales

Published online by Cambridge University Press:  01 May 2009

D. M. D. James
D. M. D. James
Affiliation:
Shell U.K. Exploration and Production Ltd Shell Centre London, S. E. 1
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Summary

The sedimentology of a key locality in the Caradoc of SW Wales is discussed for the first time. Five facies are described and interpreted: mudstones and siltstones (A), turbidite arenites (B), rudites (C), a diamictite of massflow origin (D), and muddy arenites rich in shaleclasts (E) which show a transition from massflow deposits to immature turbidites. Closely adjacent sections illustrate considerable lateral variations within an assemblage suggested to be of proximal turbidite character and to represent deposits high on a Middle Fan environment.

Type
Articles
Information
Geological Magazine , Volume 112 , Issue 3 , May 1975 , pp. 295 - 304
Copyright
Copyright © Cambridge University Press 1975

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References

Bassett, D. A. 1963. The Welsh Palaeozoic Geosyncline: a review of recent work on stratigraphy and sedimentation. In Johnson, M. R. W. & Stewart, F. H. (Eds): The British Caledonides, 35–39. Oliver & Boyd, Edinburgh.Google Scholar
Bassett, D. A. & Walton, E. K. 1960. The Hell's Mouth Grits: Cambrian greywackes in St. Tudwals' Peninsula, North Wales. Q. Jl geol Soc. Lond. 116, 85–109.CrossRefGoogle Scholar
Chipping, D. H. (1972). Sedimentary structure and environment of some thick sandstone beds of turbidite type. J. sedim. Petrol. 42, 587–95.Google Scholar
Corbett, K. D. 1972. Features of thick-bedded sandstones in a Proximal flysch sequence, Upper Cambrian, Southwest Tasmania. Sedimentology 19, 19–114.CrossRefGoogle Scholar
Davies, K. A. & Platt, J. I. 1933. The conglomerates and grits of the Bala and Valentian rocks of the district between Rhayader (Radnorshire) and Llansawel (Breconshire). Q. Jl geol. Soc. Lond. 89, 202–18.CrossRefGoogle Scholar
Griggs, G. B. & Kulm, L. D. 1970. Sedimentation in Cascadia Deep-sea Channel. Bull. geol. Soc. Am. 81, 1361–84.Google Scholar
Haner, B. E. 1971. Morphology and sediments of Redondo submarine fan, Southern California. Bull. geol. Soc. Am. 82, 2413–32.CrossRefGoogle Scholar
Harland, W. B. 1972. The Ordovician Ice Age. Geol. Mag. 109, 451–6.CrossRefGoogle Scholar
Hendry, H. E. 1973. Sedimentation of deep water conglomerates in Lower Ordovician rocks of Quebec-composite bedding produced by progressive liquification of sediment. J. sedim. Petrol. 43, 125–36.CrossRefGoogle Scholar
Keeping, W. 1881. The geology of Central Wales. With an Appendix on some new species of Cladophora, by Charles Lapworth. Q. Jl geol. Soc. Lond. 37, 141–77.Google Scholar
Keeping, W. 1882. On the geology of Cardigan town. Geol. Mag. 19, 519–22.Google Scholar
Kelling, G. 1964. The turbidite concept in Britain. In Bouma, A. H. & Brouwer, A. (Eds): Turbidites, 75–92. Elsevier, Amsterdam.CrossRefGoogle Scholar
Lovell, J. P. B. 1970. The palaeogeographical significance of lateral variations in the ratio of sandstone to shale and other features of the Aberystwith Grits. Geol. Mag. 107, 147–58.CrossRefGoogle Scholar
Marschalko, R. 1970. The origin of disturbed structures in Carpathian turbidites. Sediment. Geol. 4, 5–18.Google Scholar
Middleton, G. V. 1969. Turbidity currents. In: The New Concepts of Continental Margin Sedimentation, 1–20. Short course lecture notes, American Geological Institute, Washington. GM-A.Google Scholar
Normark, W. R. & Piper, D. J. W. 1969. Deep-sea fan valleys, past and present. Bull. geol. Soc. Am. 80, 1859–66.CrossRefGoogle Scholar
Parkash, B. 1970. Downcurrent changes in sedimentary structures in Ordovician turbidites greywhackes. J. sedim. Petrol. 40, 572–90.Google Scholar
Parkash, B. & Middleton, G. V. 1970. Downcurrent textural changes in Ordovician turbidite greywackes. Sedimentology 14, 259–93.Google Scholar
Reed, F. R. C. 1895. The geology of the country around Fishguard. Q. Jl geol. Soc. Lond. 51, 149–95.CrossRefGoogle Scholar
Ricci-Lucci, F. 1973. Sequential analysis of turbidite basins in north-central Appenines (abs). Bull. Am. Ass. Petrol Geol. 57, 801.Google Scholar
Stauffer, P. H. 1967. Grain-Flow deposits and their implications, Santa Ynez Mountains, California. J. sedim. Petrol. 37, 487–508.Google Scholar
Walker, R. G. 1967. Turbidite sedimentary structures and their relationship to proximal and distal depositional environments. J. sedim. Petrol. 37, 25–43.CrossRefGoogle Scholar
Williams, A., Strachan, I., Bassett, D. A., Dean, W. T., Ingham, J. K., Wright, A. D. & Whittington, H B. 1972. A correlation of Ordovician rocks in the British Isles. Geol. Soc. Lond. Spec. Rep. No. 3, 1–74.Google Scholar
Wood, A. & Smith, A. J. 1959. The sedimentation and sedimentary history of the Aberystwyth Grits. (Upper Liandoverian), Q Jl geol. Soc. Lond. 114, 163–95.CrossRefGoogle Scholar