Rubh' a' Mhail to Uamhannan Donna Coast
Also within
Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Coastal Geomorphology of Scotland | Favourable | — | 2017-03-10 |
| F2 | Dalradian | Favourable | — | 2011-09-22 |
| F3 | Quaternary of Scotland | Favourable | — | 2009-01-09 |
Climate exposure
This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.
Coastal habitats are exposed to sea-level rise and storm erosion. Where hard sea defences sit behind them, there's nowhere landward to retreat to — a squeeze that keeps compressing the habitat no matter how well it's managed.
Geology & landscape
Geological Feature: Moraine, Raised Beach · Geological Period: Quaternary · Rock Type: Dolomite, Quartzite
Landscape processes: Coastal, Glacial
Description
Rubh' a' Mhail to Uamhannan Donna Coast Rubh’ a’ Mhail to Uamhannan Donna Coast extends over 7 km along the north coast of Islay, from Rubh’ a’ Mhail in the east to Uamhannan Donna in the west. The boundary follows the edge of the High Rock Platform cliff line, fences and boundary walls. Seawards, the boundary extends to the mean low water spring mark. It is one of the most important sites in Britain for coastal and Quaternary geomorphology, demonstrating a range of landforms of different ages and their geomorphological relationships. Of particular note is the presence of three distinctive shore platforms that occur variously in Western Scotland and the Inner Hebrides – the High, Main and Low Rock Platforms. Two of the platforms have been modified by glaciers and the whole assemblage of features is significant in indicating past changes in the level of the sea relative to the land and the relationships of these changes to periods of glaciation. This is the classic type-locality for the High Rock Platform which here reaches widths up to 650m and is backed by cliffs up to 70m high. The platform is covered by till (glacial deposits), including the Coir’ Odhar moraine, deposited by the last (Late Devensian) ice sheet, indicating that its formation predates at least one episode of glaciation. On the seaward surface, several key sections show till on the platform overlain by raised beach gravel, indicating a period of high relative sea level as the glaciers were melting. The value of the site is additionally enhanced by the presence of two further rock platforms -the Main Rock Platform and the Low Rock Platform. These are of particular significance since this is the area where the unglaciated and tilted Main Rock Platform crosses the glaciated and nearly horizontal Low Rock Platform. The Main Rock Platform is covered by vegetated postglacial raised beach gravels. The Low Rock Platform occurs in the intertidal area. Rubh’ a’ Mhail to Uamhannan Donna coast is therefore of outstanding importance not only for the magnificently developed High Rock Platform, but for the complete assemblage of marine and glacial features and the clearly demonstrated relationships between them. The rocks of the Rubh’ a’ Mhail to Uamhannan Donna Coast are part of the Dalradian Supergroup, a sequence of metamorphic rocks which crop out across central Scotland. This site displays an outstanding section through a very large-scale fold called the Islay anticline and has the best exposures of the Bonahaven Dolomite and the overlying Islay/Jura Quartzite. The Bonahaven Dolomite is particularly important because it contains stromatolites -trace fossils formed by ancient algal mats. These are among the oldest fossils found in Scotland, probably about 650 million years old, and the rock exposures at this site provide the best examples. This site is thus of national importance for geological education and research.