Sand Volcanoes near Kilkee
County Clare, Ireland
Deep-water marine shales of the Upper Carboniferous (298-323 Million Years ago, the Clare Shales Group) define the base of the Namurian and they are overlain by sandstones from submarine fans.
Sand volcanoes are present on the upper surface of these overlying sandstones. Discovered in the 1950’s, these impressive features were formed by the extrusion of fine-grained sediment suspended in water as the sediments were compacted. These dewatering structures, along with other features such as slumped horizons within this succession, suggest high rates of basin subsidence as well as high sedimentation rates.
The rocks are part of the Gull Island Formation, which includes the Fisherstreet Slide at its base. The presence of sand volcanoes here and at Doonaha indicates additional evidence of sedimentary instability.
The Doonaha site is of County Geological Site importance and has been recommended for geological National Heritage Area designation under the IGH3 Carboniferous-Pliocene Palaeontology and IGH9 Upper Carboniferous and Permian themes.
Text courtesy of Sarah Gatley (Geological Society of Ireland and Irish Geoparks Forum)