Saturday 4 Nov

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A small happy band set off in a minibus on Friday afternoon from BGS at Keyworth heading for the Grains Bar Hotel via Stapleford and Chesterfield. Despite the M1 traffic, we managed to get to the pub before closing time (Photograph 1), where, after dinner, Dick Crofts and Simon
Price gave an introductory lecture on the Quaternary features of the Rossendale area. Recent BGS mapping by Dick and his team has led to some new insights into the Pleistocene of the area. The area has probably been covered by ice more than once, firstly during the Anglian and then the Devensian by 26kyrBP (26000 years Before Present). In Rossendale, a glaciation direction of N-S was derived from striations and to the south a series of glacial lakes was proposed to account for lacustrine sedimentary deposits. Later work has shown that certain channels are subglacial, rather than overflows between connecting lakes and we were to examine the evidence for these theories.

Our first stop on a misty Saturday morning was Cliviger Gorge where we met the day visitors. Here a tunnel valley was cut, probably during the Anglian, followed by being scoured, over steepened and deepened during the Devensian, when 2km thickness of ice overlaid it. It joins the cross-Pennine route and as the ice retreated large volumes of water deposited a valley Sandur some 70km long down into the Yorkshire Calder valley. (Photographs 2 and 3)

Our next site was Shedden Hushings, up in the clouds near some windmills which could just be made out. This area was very rough and Dick told us that it was a deposit of Ribblesdale Till, formerly rich in limestone boulders derived from exposures in Northern Lancashire. These had
been ‘hushed’ or washed through with dammed up water to sort the limestone and sandstone boulders. The limestone was taken and burnt for lime which pack ponies then took across the pennines to Halifax. Dick offered a pint for any limestone found, but even with this incentive, Simon could not find any in from the piles of sandstone.

(Photograph 4) On the way back we examined an E-W trending channel which had been proposed as a lake spillway, but the characteristic humped profile meant it was a subglacial channel. The area lay close to the edge of the ice sheet, which did not cover the Pennines, and the channel was formed under high pressure. (Photograph 5)

After a quick photostop to look at the Calder Valley, and more landslides in the mist, we headed off to Ewood Bridge for lunch and then drove up Stacksteads Gorge, a former ice filled valley. As the ice melted, Lake Rawtenstall formed, the evidence being abundant lacustrine sediments with drop stones (from floating glaciers!), part of this lake was now a school playing field with a ready-made flat surface. The final site of the day was Rushy Hill some meltwater chanels running through the exposure of the Helpet Edge Rock were visited. The Helpet Edge Rock dips S at 7° and is cut along strike by the meltwater channels, once the ice was removed, bedding plane slides occurred and deposit debris on the eastern side of the gorge. (Photograph 6) There were at least 3 other channels nearby, all with the same orientation. Darkness was falling as we made our way back to the bus, pausing to take some shots of the sandstone slabs used for walling on Lousy Hill. (Photograph 7).

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