Special calcite crystals that form when water freezes to ice in a cave have been discovered in Wookey Hole. Now the researchers would like your help to know if they exist elsewhere in the UK.

During September, 2015, Tom Chapman, Robbie Shone and Gina Moseley visited both the new show cave extensions in Wookey Hole and the passages in Wookey 20. Tom cautioned the group to be careful going past some taped-off areas protecting unusual white material sprinkled on top of the mud and rocks. The white material was present in several patches and was a mixture of different forms including fine-grained material resembling dust, and coarse grained material resembling large bread crumbs and bubbles. Having spent quite a lot of time in the Alps over the last few years with Dr. Marc Luetscher from Innsbruck University searching for this exact material, Robbie immediately recognised its potential as being ‘cryogenic cave crystals’. Gina, who has co-authored a paper with Marc on this subject, was in agreement. The finding was very exciting but completely unexpected, so the group weren’t prepared for photography or sampling. They took a few snap shots on a camera phone for record, and then took one of the bubble-type crystals with them to show to the expert, and to do further tests.

The results are now in, and the stable isotopes (oxygen and carbon) suggest very strongly that these are indeed cryogenic cave crystals. U-Th dating also shows that they aren’t modern and that they postdate the maximum extent of the last ice age, thus providing an insight into how late this region had permafrost. The group would now like to ask for your help in looking out for these unusual crystals and to let them know if you find any. Marc’s current research project involves looking at these crystals in the Alps. Now it would be great to extend the research to the UK and to reconstruct its record of permafrost history. Please pass on any information via Darkness Below.

Further information on these unusual deposits can be found in this paper by Marc et al and in this paper by Zak et al. Both papers are open source.

With thanks to Gina Moseley for this report.