View near foot of Gleann Easan Biorach, Loch Ranza, north-west Arran, Buteshire



Feature formed by weathering along junction between the Northern Granite and the local Dalradian. The granite is on the right and has a more massive appearance. The Dalradian schists on the left, with sub-vertical fabric, have been hornfelsed by the granite. The contact has obviously been a zone of weakness which has weathered out.

Arran is one of the series of Tertiary volcanic centres grouped along the west coast of Scotland and relates to a period of crustal extension between 55 and 61 million years ago. Similar aged lavas and intrusions in the Faeroes and East Greenland were all once part of the same Tertiary igneous province, before being separated by the opening of the Atlantic Ocean.

SCRAN ID: 000-000-146-605-C;British Geological Survey