|Background and site area|
The site borders that of the Aikengall Community Windfarm, which lies immediately to the west. An extension to this wind farm was granted in 2013, and at the time of site visit, construction warnings were in place along the access road, which may affect access to the site in the short term. The site comprises a naturally formed glacial meltwater channel.
A 20 m section through the Great Conglomerate Formation (Lower Devonian in age) is excellently exposed at the site, particularly on the south-facing cliffs. The cliffs are composed mostly of loosely bedded red-brown conglomerates and subordinate sandstones formed from sediment deposited by high energy streams in a series of alluvial fans at the margin of a mountain range (Photo ELC_2 P1). The conglomerate beds are up to 4 m thick, containing cobble to boulder grade (<45 cm in size) clasts of volcanic rock, quartzite and greywacke (Photo ELC_2 P2). The cobble grade clasts (<64 mm) are typically sub-rounded, elongate and flat, and display a weak to well-developed imbrication in parts of the section indicating that they were deposited by rivers flowing to the east-south-east (Photo ELC_2 P3). The conglomerate is interbedded with thin red sandstones and green, thinly laminated silty sandstones up to 5 cm thick, with rare desiccation cracks indicating periodic drying out of the wet sediment occurred during deposition.
A 50 cm wide basalt dyke (the so-called ‘Fairy Castle’) with sparse vesicles is exposed at the site (Photo ELC_2 P4), cropping out as a conspicuous rock wall in the east of the site. The dyke has baked and hardened the adjacent conglomerate (Photo ELC_2 P5).
Quaternary Deposits and Landforms
There are good examples of small talus fans forming from natural erosion of the conglomerate cliffs (Photo ELC_2 P6). The small fans are comparable in morphology to the much larger fans from which the Great Conglomerate originated. Imbricated river gravels in the bed of Burn Hope also provide a modern analogue for the development of flow-alignment in fluvial sediments that may be compared with the imbrication of clasts in the Great Conglomerate. Natural erosion by glacial meltwater has formed a deep gorge cutting the sequence. Post-glacial weathering of the partially carbonate- cemented conglomerate has resulted in a ‘badlands’ landscape, featuring boulder capped residual pillars and picturesque isolated rock stacks. The scenic nature of these pillars and stacks has historically earned the exposure the name of ‘Fairy Glen’ and ‘Fairy Castle’ (Photo ELC_2 P7).
Access and Additional Information
The site is accessed by a minor road and a short stretch of rough gravelled track. Car parking (is available off-road adjacent to the Aikengall Windfarm substation. Burn Hope is accessed south of the car park, via a small bridge, leading onto a path over open moorland. The descent into the valley of Burn Hope is steep and may be difficult when wet; care should be taken when accessing the site. Although the cliffs are not high, active erosion is ongoing with small clasts falling out of the conglomerate on a regular basis, forming small talus cones at the base of the cliffs. The basalt dyke is accessed by crossing a fence with wooden slats at the confluence of Bladdering Cleugh with Burn Hope.