Geochemistry and potential correlation of Silurian (Telychian) metabentonites from Ireland and SW Scotland

Abstract

AbstractNew occurrences of metabentonites from the Telychian Stage of the Silurian successions in SW Scotland, Co. Down and Co. Mayo, Ireland, are described in terms of their biostratigraphical setting and geochemical characteristics. The Co. Mayo occurrence extends the known distribution of Telychian metabentonites in Europe by 280 km WSW from the coast of Co. Down.Comparisons between samples based on selected trace element ratios suggest three potential correlations. One is between a tuffaceous clay from the Finny School Member, Upper Kilbride Formation of Co. Mayo, and a metabentonite from the Tara Sandstone Formation, Gala Group, Co. Down. One pair of metabentonites from the Carghidown Formation of Kirkcudbrightshire can be related to one pair from the Ardglass Formation of Co. Down. In addition, a unique alkaline chemical composition is identified in two samples from the Kirkmaiden Formation of Kirkcudbrightshire and one sample from the Ballyquintin Formation of Northern Ireland, which implies the existence of a local extensional tectonic regime at that time, consistent with a back‐arc basin.These metabentonites extend across at least two Caledonian suspect terranes and a variety of different sedimentary facies. These data may assist future discoveries and be able to improve stratigraphic correlations across three terranes. Copyright © 2003 John Wiley & Sons, Ltd.