Greenway West - Part 1

A sandy lens and beds of red marl

At the beginning of August 2019, during a trip to Barlborough, a very helpful volunteer at Barlborough Heritage Centre mentioned to me that the Clowne Branch Line Greenway was due to open soon along an old railway line that runs through nearby Clowne - and that an excellent section of geology can be found there.

An extract from Down to Earth Extra

When I saw a short article about this in the November 2019 edition of Down to Earth Extra, I decided to undertake some further research and - following a proposal at the January indoor meeting of the Sheffield U3A Geology Group - it was agreed that we would explore the area around Clowne for our April 2020 field trip.

A map of Hollinhill and Markland Grips Nature Reserve

Having been sent various information and maps by Derbyshire County Council and Derbyshire Wildlife Trust over the winter and made contact with local residents in Clowne and nearby Bolsover, who could advise me on the best routes, I made arrangements to go with Paul May to Clowne on the Saturday following our trip to Charnwood Forest.

The geology around Clowne

Arriving at the North Road Car Park in Clowne for a 10:30 am start, we were met by various people who knew the area well and had helped the Group with the planning of our walk - and who had also added to our understanding of its history.

Greenway West

With our various introductions made, we then set off on the first leg of the walk, to explore the section known locally as Greenway West, which is cut into the Magnesian Limestone escarpment to expose a 600 metre long section of the Cadeby Formation.

An extract from the  geological memoir

In the Geology of the Country Around Sheffield, the memoir which accompanies the British Geological Survey 1;50,000 series map, there is a generalised description of the dolomitic limestones that are exposed here.

A general view

It soon became apparent that the section is dominated by relatively thin beds, which are often rubbly or flaggy in nature and contain thin beds of marl, which can usually be identified by the fact that they have differentially weathered to form distinct linear features that often undercut the limestone above.

A sandy lens in flaggy beds

There is only a very gentle dip of the strata to the east and the thicknesses of the beds can be seen to change laterally, with the development of much more massive beds and the occasional appearance of lenses of sand and beds of red marl.

Examining a sand lens