Geology of the Aberfoyle district: Geohazards
|This topic provides a summary of the geology of the Aberfoyle district – covered by the British Geological Survey. 1:50k geological map sheet 38E (Scotland).
Authors: C W Thomas, A M Aitken, E A Pickett, J R Mendum, E K Hyslop, M G Petterson, D Ball, E Burt, B Chacksfield, N Golledge and G Tanner (BGS).
Rock slope failures
Areas of slipped superficial deposits and underlying bedrock are relatively common in the ground north of the Highland Border Downbend, where the rocks are gently dipping (see also Quaternary). Areas of slipped rock also occur in the south-eastern corner of the district, on the northern slopes of the Gargunnock Hills. Although most are inactive and were probably formed early in the postglacial period, there is evidence locally of minor reactivation in places. The largest landslip in the district occurs in Gleann nam Meann. This occupies about 1 km2 on the east side of the glen; the slip and associated structures extend from the floor of the glen to the ridge north of Creag na h-Airigh [NN 535 110]. The rocks exposed on the ridge and immediately to the west are strongly fissured and rotated. Most of the slipped areas are away from areas of human habitation and transport routes, so represent only a minor hazard. However, debris flows have affected a number of major roads in recent years, most particularly in 2004 (Winter et al., 2005), largely due to excessive rainfall. Thus, it is possible for previously stable deposits on slopes and higher ground to become unstable, and to flow where water tables become very high and/or high run-off destabilises deposits. Perhaps the most potentially vulnerable area is that in the steep ground above Loch Lubnaig, particularly along its eastern shore.
- Winter, M G, MacGregor, F, and Shackman, L. 2005. Scottish Road Network Landslides Study Summary Report. The Scottish Executive, 27pp.