The stratigraphy, sedimentary environments and palaeogeography of the Silurian strata of Clare Island, Co. Mayo, Ireland

The Silurian succession of Clare Island, consisting of at least 1700 m of red siltstones, sandstones and conglomerates resting unconformably on Upper Dalradian and older basement, records a cycle of marine transgression and regression within marginal marine and fluviatile sedimentary environments along the northern margin of the Silurian basin of Ireland. Clastic and pyroclastic sediments of probable Wenlock age were derived from a northern land mass formed of high grade metamorphic rocks cut by acid volcanic centres. It is argued that the source area has been removed by large scale strike-slip fault movement along a fracture zone which previously controlled the margin of the Silurian basin