On Friday and Saturday of last week I was in the Yorkshire Dales with a joint Quaternary Research Association/BCRA Cave Archaeology Group fieldtrip. This was organised by Hannah O’Regan and Trevor Faulkner to study the geomorphology and archaeology of caves in north-west England. I joined the trip on Friday morning, standing around in the humid drizzle outside Dalesbridge Centre in Austwick near Settle and being eaten by midges. The forecast was absolutely shocking but just at that point we wanted a bit more wind to clear the insects away. We got our wish, as you shall see.
A short coach trip later and the weather is already doing its best. We are standing in Kingsdale, somewhere downstream of Thornton Force and the geomorphologists are getting very animated about rival models of deglaciation. However, visibility of the relevent moraines and drumlins is a bit less than ideal.
By the time we had walked up the dale to Thornton Force the rain was nearly horizontal. However you can clearly see the moraine of glacial till to the left of the waterfall in this photo and also vast quantities of water coming down the river as well as out of the sky. We walked up the dale to the site of the former lake (rapidly filling up again) before getting back on the coach for a quick ride to the spectacular Yordas Cave. This is a former Victorian Show cave, with, on Friday at least, a raging torrent running through it. My camera was having a sulk by this point and I left it on the bus to try and let it dry out a bit so sadly I didn’t get any pictures of this. We were then supposed to walk around Ribblehead and look at the evidence for directional flow of ice sheets duing the last glaciation from drumlins mapped by Wishart Mitchell and colleagues at the Unviersity of Durham. Mysteriously, the only thing anyone could clearly perceive at Ribblehead was the Station Pub. Wishart showed us the maps and drew drumlins in the condensation on the windows of the bar whilst the big screen showed us that it was raining just as much at Headingly and Royal Ascot and all became suprisingly clear.
After dinner we met up with Tom Lord at Langcliffe and set off to look at two archaeologically important caves there. This is the entrance to Jubilee Cave. The circular cross-section indicates that the cave was formed when it was entirely full of water, what is known as a phreatic tube. Jubilee is particularly important for this blog as some of the human remains detaed to the Neolithic by Stephany Leach (see her paper on the reading list) come from the back of the chamber here. From Jubilee we set off to walk up to Victoria Cave.
Victoria Cave is much bigger. A vast cavern that was completely filled with sediment until excavations began in 1870. Tom took us through the history of the excavations and the importance of Victoria Cave to developing ideas in the 19th century about the deep past. The 19th century work was supervised by William Boyd-Dawkins and Richard Tiddeman (who fell out quite bitterly over the interpretation of the sequence). For more detail on this debate there is a recent paper by Joyce Lundberg, Tom Lord and Phillip Murphy (see the reading list again) which gives the historical background to set the scene for recent dating showing the deposits at Victoria Cave go back to Marine Isotope Stage 13. That is nearly 500 000 years ago and the oldest date for this part of the country. However, the immediately awe-inspiring thing about Victoria Cave is that it was entirely excavated by two men and supervisor. Working in controlled 2 foot wide blocks they dug away around 27 000 m3 of mud and stones between 1870 and 1878. A cubic metre of rubble weighs about a tonne (don’t ask how I know this stuff), which I make works out at about 1500 tonnes per man each year.
In this photo you can see the surviving deposits in the lower part of the mid-cave sequence. We are looking at two layers of laminated clay deposits formed under glacial conditions which are separated by three stalgamitic floors. Stalagmite, generally speaking, only forms in still air (so therefore inside caves) and when there is flowing water travelling through the limestone (so hence in intergalcial warm periods). The stalgamites in this area date to Marine Isotope Stages 13, 11 and 9 (counting from the bottom) and so formed in warm climate phases between 490 000 and 300 000 years ago.
Once we left Victoria Cave the bus struggled back through the headwaters of the River Ribble to the Dalesbridge centre for an evening lecture by Tom Lord on the recent research that gave all these dates.