| 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
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| 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. |
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| 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.
Donald McVean
Eredine, February, 1999 |
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