Castleton area (part of the Castleton SSSI)
Location and Access Information
Grid Reference: SK 150830
A number of features of geological interest can be seen in the Castleton area, as briefly described below. There is good parking on the outskirts of Castleton towards Winnat’s Pass (SK 139828), from where the features are signed and accessible.
View the site map on Nature on the Map
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Geological Interest
Blue John Mine - Castleton is well known for its deposits of Blue John, a flourspar which contains various shades of blue and purple, and which is confined to the Carboniferous Limestone outcrop of this part of Derbyshire. The mine itself extends deep into the hillside; it contains samples for viewing and also the workings the miners used hundreds of years ago. Eventually, the miners dug so deep they entered the large caverns known as Treak Cliff cavern - now accessible on the other side of the hill.
Treak Cliff Cavern - This is a naturally formed cavern which has a spectacular display of stalactite flowstone which is coloured by copper, iron and manganese.
Peak Cavern - Peak Cavern is located away from the other caverns around the Winnat's Pass area, and can be accessed via the main square in Castleton. Peak Cavern has the largest naturally occurring cave opening, formed by dissolution of the Carboniferous Limestone, anywhere in the Northern Hemisphere, and provides spectacular viewing both on the approach and once inside.
Speedwell Cavern - Another large cave system formed in the Carboniferous Limestone, located in the Winnat’s Pass area. The cave is well known for the system of flooded underground passages which are accessed by boat.
Mam Tor - Mam Tor dominates the skyline to the west of Castleton and is famous for the large landslide that dominates its eastern face. The hill itself is formed in shales and sandstones of Upper Carboniferous age overlying Carboniferous Limestone. These are well exposed in the main face as a result of the large landslide. This feature, which is still moving at a rate of up to 1m/year, has been active for at least 3000 years and represents the slippage of the upper sequence of shales and sandstones along a fault and horizon of clay within the main mass of shales.
Following heavy rainfall the plane of weakness is lubricated and the overlying rocks slide along its surface. Despite repeated attempts to stabilise part of the face continued slippage led to the closure of the main road westwards from Castleton in 1979. This is why the only access route of the village is now via the steep and twisting Winnat's Pass.
