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Environment of deposition of conglomerates from the Silurian of north Galway, Ireland

Published online by Cambridge University Press:  03 November 2011

D. Michael Williams  and
P. D. O'Connor
D. Michael Williams
Affiliation:
Department of Geology, University College, Galway, Republic of Ireland.
P. D. O'Connor
Affiliation:
Department of Geology, University College, Galway, Republic of Ireland.
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Abstract

Conglomerates from the Lettergesh Formation in the Silurian sequence of N Galway, Ireland, demonstrate palaeocurrents from the NE. Fabric studies demonstrate that the conglomerates were emplaced largely by traction currents and not by down-slope sliding or dispersive currents. Stratigraphic relationships demonstrate that the conglomerates were deposited in an environment which was adjacent to fluviatile, shallow-marine and deeper shelf facies at different times. A fan-delta environment of deposition is suggested, which requires a modification of previous Silurian sea-level curves at, or near, the base of the Wenlock.

Keywords

Clasticfabricfan-deltamarinePalaeozoic.
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 78 , Issue 3 , 1987 , pp. 129 - 132
Copyright
Copyright © Royal Society of Edinburgh 1987

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References

Boucot, A. J. 1975. Evolution and extinction rate controls. Amsterdam: Elsevier.Google Scholar
Damuth, J. E., Kolla, V., Flood, R. D., Kowsmann, R. O., Monteiro, M. C., Gorini, M. A., Palma, J. C. & Belderson, R. H. 1983. Distributary channel meandering and bifurcation patterns on the Amazon deep-sea fan as revealed by long-range side-scan sonar (GLORIA). GEOLOGY 11, 94–98.2.0.CO;2>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, 1200–1216.Google Scholar
Doeglas, D. J. 1962. The structure of sedimentary deposits of braided rivers. SEDIMENTOLOGY 1, 167–190.CrossRefGoogle Scholar
Goreau, T. & Burke, K. 1966. Pleistocene—Holocene geology of the island and shelf near Kingston, Jamaica. MAR GEOL 4, 207–225.CrossRefGoogle Scholar
Harms, J. C., Southard, J. B., Spearing, D. R. & Walker, R. G. 1975. Depositional environments as interpreted from primary sedimentary structures and stratification sequences. SOC ECON PALAEONTOL MINERAL SHORT COURSE NO. 2, Dallas, Texas.CrossRefGoogle Scholar
Hiscott, R. N. & Middleton, G. V. 1980. Fabric of coarse deep-water sandstones, Tourelle Formation, Quebec, Canada. J SEDIMENT PETROL 50, 703–722.Google Scholar
Ince, D. 1984. Sedimentation and tectonism in the Middle Ordovician of the Girvan district, SW Scotland. TRANS R SOC EDINBURGH EARTH SCI 75, 225–237.CrossRefGoogle Scholar
Laird, M. G. & McKerrow, W. S. 1970. The Wenlock sediments of north-west Galway Ireland. GEOL MAG 107, 297–317.CrossRefGoogle Scholar
Lindholm, R. C. 1980. Intraclast orientation in Cambro-Ordovician limestones in western Maryland. J SEDIMENT PETROL 50, 1205–1212.CrossRefGoogle Scholar
McKerrow, W. S. 1979. Ordovician and Silurian changes in sea level. J GEOL SOC LONDON 136, 137–145.CrossRefGoogle Scholar
McKerrow, W. S. & Campbell, C. J. 1960. The stratigraphy and structure of the Lower Palaeozoic rocks of north-west Galway. SCI PROC R DUBLIN SOC A1, 27–52.Google Scholar
Piper, D. J. W. 1967. A new interpretation of the Llandovery sequence of North Connemara, Eire. GEOL MAG 104, 253–267.CrossRefGoogle Scholar
Piper, D. J. W. 1970a. Geosyncline margin sediments in the Silurian of west Connacht, Eire. MEM AMER ASSOC PET GEOL 12, 289–297.Google Scholar
Piper, D. J. W. 1970b. A Silurian deep-sea fan deposit in western Ireland and its bearing on the nature of turbidity currents. J GEOL 78, 509–522.CrossRefGoogle Scholar
Piper, D. J. W. 1972a. Sedimentary environments and palaeogeography of the late Llandovery and earliest Wenlock of north Connemara, Ireland. J GEOL SOC LONDON 128, 33–51.CrossRefGoogle Scholar
Piper, D. J. W. 1972b. Turbidite origin of some laminated mudstones. GEOL MAG, 109, 115–126.CrossRefGoogle Scholar
Pudsey, C. J. 1984. Fluvial to marine transition in the Ordovician of Ireland—a humid-region fan-delta? GEOL J 19, 143–172.CrossRefGoogle Scholar
Rickards, R. B. 1972. On some highest Llandovery red beds and graptolite assemblages in Britain and Eire. GEOL MAG 109, 70–72.Google Scholar
Rust, B. R. 1972. Pebble orientations in fluvial sediments. J SEDIMENT PETROL 42, 384–388.Google Scholar
Smith, R. M. H. 1986. Sedimentation and palaeoenvironments of Late Cretaceous crater-lake deposits in Bushmanland, South Africa. SEDIMENTOLOGY 33, 369–386.CrossRefGoogle Scholar
Stanley, D. J. & Unrug, R. 1972. Submarine channel deposits, fluxoturbidites and other indicators of slope and base-of-slope environments in modern and ancient margin basins. In (eds) Rigby, J. K. & Hamblin, W. K.Recognition of ancient sedimentary environments. SOC ECON PALAEONTOL MINERAL SPEC PUBL 16, 287–340.Google Scholar
Walker, R. G. 1975. Generalized facies models for resedimented conglomerates of turbidite origin. AMER ASSOC PET GEOL BULL 86, 737–748.2.0.CO;2>CrossRefGoogle Scholar
Walker, R. G. 1976. Turbidites and associated coarse clastic deposits. GEOSCI CANADA 3, 25–36.Google Scholar
Wescott, W. A. & Ethridge, F. G. 1980. Fan-delta sedimentology and tectonic setting—Yallahs fan-delta, southeast Jamaica. AMER ASSOC PET GEOL BULL 64, 374–399.Google Scholar
Williams, D. M. 1984. The stratigraphy and sedimentology of the Ordovician Partry Group, southeastern Murrisk, Ireland. GEOL J 19, 173–186.CrossRefGoogle Scholar
Williams, D. M. & Nealon, T. 1987. The significance of large-scale sedimentary structures in the Silurian of western Ireland. GEOL MAG 124, 361–66.CrossRefGoogle Scholar
Ziegler, A. M. 1965. Silurian marine communities and their environmental interpretation. NATURE 207, 270–272.Google Scholar
Ziegler, A. M., Cocks, L. R. M. & Bambach, R. K. 1968. The structure and composition of lower Silurian marine communities. LETHAIA 1, 1–27.CrossRefGoogle Scholar