Monday, 23 November 2015

Peveril Castle

The keep at Peveril Castle

Having explored the Burbage Valley a couple of weeks earlier, I was reminded that a steep climb is quite often involved when exploring the geology of the Peak District but I had forgotten how daunting the view of Peveril Castle is, when looking up and contemplating the walk ahead.

A remnant of the curtain wall seen on the approach to Peveril Castle

Set on a steep hill, with precipitous cliffs dropping down to Peak Cavern on one side and to Cave Dale on another side, it must have once been such a formidable sight and I can't ever remember seeing such a spectacular defensive position, having explored very many of England's castles

Limestone walling at Peveril Castle

The geology here is the Lower Carboniferous Bee Low Limestone Formation, which was laid down in a shallow sea - as apron reefs on the edge of a shelf - and it is often rich in corals and fossil shells. The fragments of the curtain wall and other structures that still remain, and the occasional outcrops within the grounds, show the general physical characteristics of the rock.

Ashlar facing to a rubble core at the castle keep

Although the Carboniferous limestone has been used for coursed rubble walling, it is not suitable for fine ashlar and the keep is faced in gritty Carboniferous sandstone of unknown provenance; the nearest source of massive sandstone is some distance away and, thinking about moving heavy stone over such terrain, it makes the already difficult task of constructing the castle seem even more impressive.

An architectural detail

Most of the sandstone ashlar has been stripped away, leaving the rubble core exposed, but the remaining facing stones are still in very good condition, although the interior stonework is suffering from severe cavernous decay.

The interior of the keep

Peveril Castle isn’t the most impressive Norman castle in England but, once you have zigzagged up the hill to get there, the views of Mam Tor, Back Tor and Lose Hill are worth making the effort.

A panoramic view of the Shale Grit and Mam Tor Beds

These form part of a long ridge comprising the Shale Grit and Mam Tor Beds that, together with the underlying Bowland Shale, are the oldest Upper Carboniferous rocks in this part of England and were laid down as turbidites ahead of the approaching delta front.