Frodsham Railway and Road Cuttings (SSSI)
Location and Access Information
Grid Reference: SJ 518774, SJ 520780, SJ 519781
Cross-bedded desert sandstones
These railway and road cuttings are located in the village of Frodsham, North Cheshire, just to the south of Runcorn. The cuttings expose Triassic sandstones. The railway cutting is adjacent to the footbridge over the line close to the station. The road cutting is in the main village centre, 300m east of the Church. Parking is available in the village.
View the site map on Nature on the Map
.
Geological Interest
During the Triassic (205-142 million years ago), Britain lay close to the equator and was part of a large continental landmass over which arid, desert conditions predominated. This site provides evidence of the nature of the Triassic environment and consists of three separate exposures of the Frodsham Member, a sequence of sandstones representing the upper part of the Triassic Helsby Sandstone Formation.
Structures present within the sediments of the outcrops indicate that the sandstones were originally deposited by large desert sand dunes. The orientation of the planes observable in the exposures indicate that the winds responsible for the formation of the dunes blew from the east and southeast. At Pinmill Brow these desert dune deposits are overlain by the Tarporley Siltstone Formation which had a very different origin, being laid down by either marine intertidal or fluvial deposition.
