The Ardnamurchan Volcano - 2

The Ardnamurchan volcanic complex is one of a line of igneous centres which runs from Skye and Rhum in the north through Mull, Arran, the Mourne Mountains and Carlingford in Ireland and down to Lundy Island in the Bristol Channel. They all date from roughly the same time, between about 65 million years ago and 50 million years for Lundy.

The cause of this extensive activity was the breaking away of Greenland from the northwest of continental Europe. It started with great rift valleys forming along the line of rupture, into which vast amounts of basaltic lava bled out to smother the ancient landscape. These lavas are marked in purple in the map. While layer upon layer of these 70-million year old lavas are visible in Skye and Mull (photo shows lava flows on the north coast of Mull, opposite Kilchoan), they are best seen in Northern Ireland, where they form the famous Giant's Causeway.

The volcanoes, marked in red on the map, punched their way through these recently-cooled lavas. They were probably the surface expression of a great plume of magma rising in the mantle which migrated as the overlying continental material moved. As a result, each of the volcanoes is slightly different. Ardnamurchan is, in many ways, the simplest in structure and, being compact and well-exposed, is relatively easy to study. The plume is still active today, pouring out lavas from Iceland's volcanoes.