WINNATS PASS

Winnats Pass Derbyshire UK

Winnats, as shown on some Ordnance Survey maps) is a hill pass and limestone gorge in the Peak District of Derbyshire, England. 

The name is a corruption of 'wind gates' due to the swirling winds through the pass. It lies west of the village of Castleton, in the National Trust's High Peak Estate and the High Peak borough of Derbyshire. The road winds through a cleft, surrounded by high limestone ridges. At the foot of the pass is the entrance to Speedwell Cavern, a karst cave accessed through a flooded lead mine, and which is a popular tourist attraction.

In the 1930s Winnats Pass was the location used for annual access relays in support of greater access to the moorlands or the Peak District, around the time of the Mass Trespass of Kinder Scout. At their peak these were attended by up to 10,000 people.

The permanent closure of the main A625 road at Mam Tor in 1979 due to subsidence has resulted in Winnats Pass being heavily used by road traffic. However, the narrowness of the road and its maximum gradient of over 28% (1 in 3+1⁄2) has caused it to be closed to buses, coaches and vehicles over 7.5 tonnes in weight. The road regularly features in the Tour of the Peak cycle race each autumn.

Geological formation

The gorge of Winnats Pass was once thought to have originated as a giant collapsed cavern however, this idea has since been superseded. 

Winnats Pass can be seen to cut steeply down through Lower Carboniferous limestone rocks. These were formed approximately 340 million years ago as a reef fringing a shallow lagoon, with deeper water beyond. The presence of a small outcrop of fossiliferous rock (known as 'beach beds') at the base of Winnats Pass, close to Speedwell Cavern, suggests that a contemporary underwater cleft or canyon once existed within the active reef which caused the build up of shelly and crinoidal remains at its base. All these sediments were subsequently buried together under Namurian sandstones and shales in the subsequent Upper Carboniferous period. 

They were subsequently uplifted, but were only re-exposed by periglacial erosion towards the end of the Pleistocene. Melting water would have flowed along any lines of weakness within the reef limestone, such as those created by the presence of the original underwater cleft in the reef, carving out the gorge seen today.