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The significance of large-scale sedimentary structures in the Silurian succession of western Ireland

Published online by Cambridge University Press:  01 May 2009

D. Michael Williams  and
T. Nealon
D. Michael Williams
Affiliation:
Geology Department, University College, Galway, Ireland
T. Nealon
Affiliation:
Geology Department, University College, Galway, Ireland
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Abstract

Large-scale sedimentary structures are described from the Lough Muck Formation (Wenlock) of north Galway, Ireland. They consist of bed packages separated by truncation surfaces of varying orientations. They had previously been interpreted as rotational slumps generated on a shelf–slope interface. It is shown that the structures formed in a tidally influenced environment far removed from a slope. They bear strong similarities to structures described from other tidal channel environments and it is proposed that they represent deposition on aggradational margins of such channels. The supposed slope–shelf transition is therefore not present at this level in the Silurian succession and much of the Lough Muck Formation may be of a dominantly shallow-marine origin.

Type
Articles
Information
Geological Magazine , Volume 124 , Issue 4 , July 1987 , pp. 361 - 366
Copyright
Copyright © Cambridge University Press 1987

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