2: The Dalradian rocks of Knapdale and North Kintyre

Abstract

Introduction The area under consideration lies 50 km south of Oban and 80 km west of Glasgow, in the South-west Highlands of Scotland. It is limited by the shores of Loch Fyne to the east and by the deeply indented coast-line of the Sound of Jura to the west. The inland exposures are poor. However, the rocks are well-exposed on the smooth glaciated surfaces which form the shores of Loch Fyne and on the raised beaches which form the coastlines of Loch Sween and Loch Caolisport along the Sound of Jura. General Geology The Dalradian rocks found in Knapdale and North Kintyre form a stratigraphic sequence extending upwards from the Ardrishaig Phyllites to the Beinn Bheula Schists. The Ardrishaig Phyllites are formed by greenish phyllites, often interbedded with minor amounts of limestone and fine-grained quartzite. They are succeeded by the Crinan Grits as a group of pebbly quartzites characterized by graded bedding. A transitional group of calcareous phyllites, fine-grained quartzites and pebbly quartzites is found in some places as the Ardnoe Beds between the Ardrishaig Phyllites and the Crinan Grits. The Crinan Grits are affected in Knapdale by a major fold known as the Kilmory Bay Syncline. This fold is flanked to the north-west by the Loch Sween Anticline and the Tayvallich Syncline. Together, these folds form the compound Loch Awe Syncline in south-west Argyll. The Ardrishaig Phyllites are exposed on the south-eastern limb of the Kilmory Bay Syncline where they occupy the core of a major fold known as . . .