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Sedimentation and palaeogeographical significance of the Silurian rocks of the Louisburgh–Clare Island succession, western Ireland

Published online by Cambridge University Press:  03 November 2011

C. Kelly Maguire
Affiliation:
Geochem Group Ltd., Chester Street, Chester, CH4 8RD, UK
John R. Graham
Affiliation:
Department of Geology, Trinity College Dublin, Dublin 2, Ireland

Abstract

There are three distinct Silurian successions exposed in South Mayo and North Galway, western Ireland, of which the Louisburgh-Clare Island succession is the most northerly. It is separated from the adjacent Croagh Patrick succession by the Emlagh Fault. Three of the formations (Strake Banded, Knockmore Sandstone, Bunnamohaun Siltstone) in this 1·5 km Louisburgh–Clare Island succession had previously been interpreted as intertidal to offshore marine deposits. Almost all the facies present display characteristics of fluvial sedimentation and there is evidence for a contemporaneous volcanic centre to the west of the present outcrop. The exceptions are some grey laminated mudrocks with a fragmentary fauna which are interpreted as lacustrine and which show striking similarities to parts of the Silurian inliers in the central Midland Valley of Scotland. Despite these similarities the evidence for direct connection between western Ireland and Scotland is unproven. Within western Ireland correlations are hindered by uncertainties of the age of the Louisburgh-Clare Island succession and the age span of the adjacent Croagh Patrick succession.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1995

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