Lochs and Glaciers
The Loch Awe Glacier - One of the last in Scotland
From where I am standing at the Trig Point 353m above sea level on Corr Bheinn to the SE of Eredine Village I can see the broad ribbon of Loch Awe from its southern end at Ford to the narrows at Inverinan, both six or seven miles away as the raven flies. Had I been standing at this same point only 10,000 years ago I would have been looking down not on a shining stretch of water but on the rather grim grey-white of a decaying ice field, closer to me and broader than the future loch, because extending upward a further 20 - 30m in height, and littered with tumbled rock debris at its margins.
At this time the land was just emerging from the last Scottish ice advance of the long glacial epoch. The advancing West Highland glaciers had just been halted by rapidly rising temperatures at Corran narrows on Loch Linnhe, at the mouth of Loch Creran, at Connel, Pennifuir, Loch Nell and in Glen Scammadale, some distance down Loch Fyne and at the southern end of Loch Lomond where the traces of these times were first recognised and which has therefore given a title - the Loch Lomond Advance (Stadial) - to the whole episode. In fact, the fluvio-glacial features of Loch Awe, especially at its southern end, are finer than those of Loch Lomond and among the most impressive evidence of recent glaciation in Europe
The ice front of the glacier lay in the neighbourhood of Ford. Melt water poured along the margins of the ice and spouted from beneath it, carrying sand, gravel and boulders downstream, towards the gap in the ridge at Eurach and directly south through Kilmichael Glen. Down the east side of the loch today you can see how the sandy and gravelly deposits of the melt water are now covered with green farmland and the rocky areas between, swept clear by the ice, occupied by acid moorland or forest plantations. There are some fine boulder ridges of the old lateral moraine in the hillside forest around Eredine Village and an impressive section of boulder clay/till has been excavated in the car park below the road to Durran. The morainic boulders are mostly local quartzites, showing that they have not been carried very far, unlike the boulders of the previous glaciations which could well be granite from the Blackmount and Rannoch Moor. Boulder till formed beneath the ice so that the stones in it have come further and from many sources.
There is a sinuous ridge of sandy gravel (an esker) just above Durran showing where one of the melt water streams along the edge of the ice dropped its load and other eskers can be seen at the south end of the loch along with terraces and kettle holes, where isolated masses of melting ice have left little rounded lochans.
The trench of Loch Awe had been occupied by ice before, of course, the glaciers gouging out rock to a depth of some 90m. Throughout post-glacial times sea levels were rising as the ice melted world-wide and at the same time the Scottish coast was rebounding as it was relieved of the inconceivable weight of the ice sheets. The situation was complicated and is still not completely understood but it did result in the formation of the long recognised raised beaches of the Clyde coast and western Argyll. For a period Loch Awe was one of the Argyll fjords and you can see that it too has its raised beach still visible in many places as a low cliff line or steepening slope a few metres back from present high water level.
The accumulation of debris at the south end of the loch finally blocked all drainage by that route and the pent up water spilled along an old geological fault line through the Pass of Brander, now clear of ice. At the present day Loch Awe thus drains from the "wrong" end and enters the sea in Loch Etive instead of at Crinan.
Eredine, February, 1999