The Don Gorge

A view of the Magnesian limestone escarpment

In previous posts, I have briefly described a few places along the Magnesian limestone escarpment, which I hadn’t visited before – including Pontefract, South Elmsall and Creswell Crags - to assess their potential for field trips.

The geology around the Don Gorge

Together with many other RIGS that I surveyed for Doncaster MBC, these sites are recommended to anyone who wants to know more about the Permian geology of this part of England.

Further to the north of Maltby Crags, shortly after its confluence with the River Dearne, the River Don cuts through the limestone escarpment to eventually form the Don Gorge.

At Cadeby Cliff, across the valley from Conisbrough, several bryozoan reefs stand out from the head, which has crept down the slope, and there are also some very rare exposures of cemented fluvio-glacial sediments, flowstone and excellent examples of crystalline calcite.

 

A detail of fluvio-glacial sediments at Cadeby Cliff

Walking further along the River Don beyond Conisbrough Viaduct, the Don Gorge is now heavily wooded - with nature reserves - but the quarrying industry has left its mark all along its length; although there are no longer any coal mines in South Yorkshire, the dolomitic limestone here is still used for making steel and glass, as well as for constructing and repairing roads and buildings.

A view of Conisbrough Viaduct and the Don Gorge

Although much of the terrain around here is difficult to explore, the large scale slumping and development of large rifts – infilled by loose sand and breccia – adds to its geological interest, as does the appearance of red marl.

A rift filled with limestone breccia and sand