Ardalanish Bay
Also within
Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Caledonian Igneous | Favourable | — | 2017-03-10 |
| F2 | Moine | Favourable | — | 2022-01-18 |
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: Rock Outcrop · Geological Period: Devonian, Silurian · Rock Type: Granite
Landscape processes: Coastal, Volcanic / Igneous
Description
ARDALANISH BAY Ardalanish Bay preserves the most westerly known outcrop of the Neoproterozoic-age Moine Supergroup in Scotland. The exposed succession comprises semipelite and pelite lithologies, representing the Assapol Striped and Banded Formation of the Assapol Group and importantly correlates with the Glenfinnan Group on the Mainland. The site is nationally important as it provides a well-documented example of the effect of a late orogenic pluton, the Silurian/Devonian-age Ross of Mull Granite. The earlier regional metamorphic assemblages in the Moine succession which includes kyanite mineralogy have been overprinted by the metamorphic aureole with the formation of andalusite and sillimanite. Although all three aluminosilicate polymorphs occur within the restricted area of the thermal aureole they do not co-exist at a single locality. The site also is representative of the Ross of Mull Granite pluton, which provides one of the most definitive examples of passive emplacement with assimilation of county rock within any of the Caledonian plutonic suites. Within the coastal outcrops on the western side of Ardalanish Bay, all stages are preserved, from the impregnation of the Moine country rocks by granite sheets, to the spalling off and sinking of slabs and blocks of country rock into the granite magma (stoping). Assimilation of the metasedimentary material into the marginal granite resulted in the development of a contaminated hybrid granite and localised ponding of fluids in the magma led to the crystallisation of pegmatite. The inner porphyritic biotite granite of the pluton is also represented in the site. Moine Caledonian Igneous