Geology in Alport

Rapids in the River Lathkill at Alport

When planning my trip to Youlgrave, to investigate the building stones in the village and the construction history of All Saints church, I had to organise my time around the irregular rural bus services and decided to have a look at the geology around Alport. 

The geology around Alport

Back in 1995, I had undertaken a survey of the RIGS (Regionally Important Geological Sites) in the Peak District National Park and had briefly investigated Lathkill Dale and Bradford Dale, whose confluence is at Alport, but I don’t recall seeing the exposures of Pleistocene tufa here. 

A view across lower Lathkill Dale from Alport Lane

During trips to Monsal Dale and Matlock Bath with the Sheffield U3A Geology Group, I had previously encountered tufa – where the springs are still exploited commercially as petrifying wells for the tourists at the latter – but the Alport tufa was reputedly the largest deposit in Derbyshire and was widely used for buildings in the area. 

A general view of Tufa Rock

Having finished exploring All Saints church, I walked down to Alport and immediately went to find the tufa to the north-east of Rock House on Alport Lane, which has been given the name Tufa Rock. Formed by precipitation of calcium carbonate from springs, the exposures here are several metres high and, although much of the rock is overgrown, it is possible to study them from the track that passes the side of the houses. 

A close up view of Tufa Rock

I didn’t examine it closely, but the irregularly bedded mass and very open, porous texture distinguishes it from the Carboniferous limestone - the well bedded Eyam Limestone Formation – that forms crags on the east side of the wide valley to the north of Rock House. 

A view up Lathkill Dale from Tufa Rock

After taking a few photographs, I crossed to the west side of the valley in which the River Lathkill flows and made my way north along Lathkill Dale, where I hoped to be be able to get to Conksbury Bridge, where I had previously encountered vesicular basalt in the area that rises above the path, as well as blocks of limestone in the river bed, which were packed full of fossil brachiopod shells. 

Crags of the Eyam Limestone Formation in Lathkill Dale

Not having an Ordnance Survey map with me, and being unable to remember exactly where I had found these rock exposures, I set of walking as fast as I could; however, although I saw outcrops of the Eyam Limestone in the crags on the east side of Lathkill Dale, when consulting a fellow walker with a detailed map, I realised that I wouldn’t have the time to explore the area fully and turned back to Alport. 

A weir on the River Lathkill

Still with time before I had to catch my bus back to Bakewell, I then followed the River Lathkill along its course to the point where it meets the River Bradford, and during which it falls over weirs, possible tufa barrages, and ledges of limestone that form shallow rapids in the river bed below the road bridge on Alport Lane. 

The River Lathkill below Alport Lane bridge

Walking a short distance up Bradford Dale, I soon encountered Rheinstor Rock, which is composed of massive beds of the Eyam Limestone Formation – as marked on the geological map - and is a very popular locality for rock climbers.

Climbers at Rheinstor Rock

I didn’t examine the outcrop closely, to determine the presence of fossils and therefore confirm that it was Carboniferous limestone, but the rock seemed to be full of voids and I did wonder if this might be in fact another outcrop of the tufa.

Rheinstor Rock