Laikenbuie Ecology Trust

The area in the Laiken Glen shows clear evidence of modification by glacial action. During the last Great Ice Age most of the British Isles north of a line between the Bristol Channel and the Thames Estuary was covered by ice-sheets, spreading out from centres of distribution in the high ground of several areas in Scotland, the Lake District and North Wales. The exact events during this period are still a matter of geological dispute, but it seems likely that there were a number of inter-glacial periods with climate warming and formation of gravel and sediment deposits associated with the local retreat of ice-sheets.

The general direction of movement of the ice in the Moray Firth area was thought to be west to east and this often accounts for the similar orientation of many glens in the present day. The low valley at Laikenbuie also tends to reflect this trend.

Another very well developed feature on either side of Nairn is the raised beach inland from the present day coastline along the Moray Firth. These ramp-like features mark the old coastline that has since been modified due to the land surfaces rising after the removal of the great weight of overlying ice.

Prior to the ice-sheets and glaciers developing, the landscape would have been reworked and modified largely by the action of rivers and other modes of sub-aerial erosion. The present day drainage system will be a reflection of the pattern produced by the erosive action of the ice which may or may not be similar to the pre-glacial drainage pattern.

Boulder Clay is one of the deposits most indicative of glacial activity and it left behind by the vast melting ice-sheets that have overspread lowland areas. It comprises rocks and pebbles of various sizes and rock types held in a clay composed partly of crumbled soil and rock, and partly of unaltered rock-flour ground by the ice as it moved. It is usually deposited in level layers in-filling any irregularities in the underlying land surface – so it can be thick in pre-glacial valleys, but thin or even absent on the valley margins. The topography characterised by boulder clays can be quite variable and at Laikenbuie it has formed low ridges that are traceable for long distances called ‘eskers’ that are thought to have been formed by active streams under the ice-sheets.

U-shaped valleys are another characteristic feature of glacial landscape, developed by the abrasive action of an essentially rigid substance on the underlying rock. While water tends to create sharp overlapping spurs and narrow, deep V-shaped profiles, the ice typically smooth or straighten out the valley sides and scoop out rock material from the valley bottom.

Another feature seen at Laikenbuie is the presence of large, flat piles of medium to large rounded boulders close to some open field and gorse at the western end of the area. It is likely that these are glacial boulders cleared from the surrounding land, although it was considered at one point to perhaps have been the results of moraine material left by the melting ice.

An exposure of relatively unconsolidated sands found deep in some undergrowth below the iron age settlement site is very curious. It exhibits layering that is rhythmical with alternating light buff/yellow sand and darker brown clayey layers. There is some suggestion of faint cross-bedding and the sands are rounded and of fairly similar grain size. Such a deposit may well have been produced by overflow channels from a melting body of ice, or within a temporary glacial lake that was again created by the melting of the retreating ice. The idea that a glacial lake at one time filled parts of the lower area of the Laikenbuie site is quite possible and perhaps the present day lakes and wetland area is a remnant of this feature.

It is generally accepted that the Pleistocene glaciation (less than 1 million years ago) was not a single event, but was a series of cold periods separated by warmer, interglacial periods when the ice-sheets shrank back to form small glaciers like those seen today in Scandinavia and Alaska.