Carn a' Bhealaich Mhoir
Also within
Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Moine | Favourable | — | 2005-03-31 |
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
Landscape processes: Coastal
Description
CARN A’ BHEALAICH MHOIR Carn a’ Bhealaich Mhoir Site of Special Scientific Interest (SSSI) lies southeast of Plockton, in the hills overlooking Loch Carron. The site displays nationally important features of the Moine Thrust Zone. The Moine Thrust is a major fracture in the Earth’s crust, which runs along Scotland’s north-western seaboard from Loch Eriboll on the north coast to the Sleat peninsula. The Thrust is one of the most important features of Highland geology and was formed around 430 million years ago during a mountain-building event known as the ‘Caledonian Orogeny’. The Moine Thrust Belt extends westwards from the Moine Thrust and encompasses a number of other thrusts and associated nappes (‘slabs’ of rock bounded by thrusts). The Carn a’ Bhealaich Mhoir SSSI contains the most informative part of an unusually extensive section of traceable contact (uninterrupted by faults) between Lewisian and Torridonian rocks within the Moine Thrust Belt. The rocks are part of the ‘Kishorn Nappe’, the lowest unit of the Moine Thrust Belt in the Lochalsh district. The contact between the two rock types is an unconformity – the younger Torridonian rocks having been deposited as sediment on a land surface carved from the older Lewisian rocks. However, the rock sequence has been overturned by folding, so that the older Lewisian rocks now lie above the younger Torridonian rocks on the ‘inverted limb’ of a fold structure known as the ‘Lochalsh Syncline’. Shearing and ‘mylonitization’ (crushing) of rock near the contact between the Lewisian and Torridonian indicates that, during the Caledonian Orogeny, a zone of high strain was concentrated along the unconformity. The shearing has erased any evidence of the shape of the original Lewisian landscape; however, blocks of Lewisian rock incorporated into the Torridonian, provide evidence for the original nature (unconformity) and orientation (Torridonian above Lewisian) of the contact. The site is a remarkable example of an overturned unconformity and is of national importance as the best locality to study the Lewisian-Torridonian contact and the effects of deformation in the Kishorn Nappe.