Long Berry Coast
Also within
Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Non-marine Devonian | 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
Geological Period: Devonian · Rock Type: Dolomite, Sandstone
Landscape processes: Coastal
Description
Long Berry Coast Long Berry Coast Site of Special Scientific Interest (SSSI) extends approximately 1km along the coast south of Wick, Caithness. The site has been designated as an SSSI because it represents the best section in Caithness for demonstrating the rock sequence of the Middle Devonian Wick Flagstone Group, and understanding the sediments of the Orcadian Basin environment. It is also of great importance for studying post-depositional changes in lake sediments. During the Devonian period (416-359 million years ago), the Orcadian Basin (a low-lying, broad valley-like depression) extended from the Moray Firth to Norway. At the valley’s lowest point, there was a large freshwater lake called Lake Orcadie. The sediments that were deposited at what is now Long Berry Coast SSSI were washed into Lake Orcadie from the surrounding high ground. The outcrops at Long Berry Coast SSSI show a range of sedimentary structures that are typical of ‘Caithness Flagstones’. The rocks consist of mudstones, siltstones and fine sandstones with occasionally thicker sandstone beds. The outcrops show annual cyclic layers (known as varves) of fine sand, silt, carbonate and organic material from the centre of Lake Orcadie. The outcrops also show layers that contain fish fossils. Within the rock sequence there are layers of dolostone, formed from the mineral dolomite. These harder dolostone layers were often broken up and disjointed as the surrounding soft sediment was squeezed by further accumulating sediment above. The rocks at Long Berry Coast SSSI also show that the lake fluctuated in depth. Ripples in the outcrops formed in sand under shallow water conditions. Polygonal marks that show where mud cracked when it was exposed to the air, demonstrate that Lake Orcadie almost dried up during some periods. The mud cracks within the flagstone layers (known as synaeresis) also indicate salinity changes within the lake.