Creigiau Llansteffan (Llanstephan Cliffs)
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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
Rock Type: Conglomerate, Limestone, Sandstone
Landscape processes: Coastal, Fluvial
Description
Description The site shows a coastal section exposing the Psammosteus Limestone horizon and overlying sandstones and shales, within the Red Marl Group of the Lower Old Red Sandstone. Here the Psammosteus Limestone is made up of a series of very mature calcrete profiles, closely stacked and coalescing. The overlying sediments have examples of both large fluvial sand bodies formed by the main rivers depositing the Red Marls and deposits of small, ‘interfluvial' distributaries which formed muddy, sometimes meandering, channels with little sand, but much intraclast conglomerate. This locality is a key one for understanding the geomorphology of the Welsh Lower Old Red Sandstone alluvial plain. The site has been used in publications outlining the significance of the calcretes (as it has some of the best examples of very mature profiles), and the nature of the drainage pattern of the alluvial plain in the Lower Old Red Sandstone.