Yesterday we went to Bull Pot of the Witches to 'dive' the sumps that separate the upstream and downstream sections of the cave and come out from the upstream section via Gour Chamber; given the prolonged dry spell of weather that we are experiencing we were confident that the sumps would have broken. When we reached the first sump (going upstream) it was indeed bone dry, but the second sump was still a sump. Previously in such dry conditions we'd found that the 'sump' consisted of a short (1 or 2 metres) descent down a gravel slope to a short section of horizontal passage with a foot or two of water and maybe 3+ feet of air-space, beyond which there was a steep-ish upward slope of maybe two or three metres to the start of the upstream section of the cave at the bottom of the hading rift that descends from Gour Chamber. Yesterday, however, the water level was still quite high, so we deduced that something must have changed, as we were both pretty certain that we'd been here in less dry conditions to find the sump open.
So we decided to have a bimble round the downstream section of the cave, and visit the sump. The passage here had changed as well. Whereas before there was open passage before the sump, with some nice mud formations, now there were tons of gravel everywhere, reducing the final bit of passage – that I remember as having been easy walking-size – to a flat-out crawl. We saw no sign of the mud formations, either, deducing that they must have been covered in gravel.
So, it looks as though there has been a major flood event sometime in the last year or two that has brought in tons of gravel. Where on Earth did it come from? Did it get washed through the sump from Aygill Caverns? It strikes me as remarkable that so much stuff could have got transported all that way without getting dumped en route (apart from that dumped in the sump-that-no-longer-dries-out, presumably). Any thoughts, anybody?
So we decided to have a bimble round the downstream section of the cave, and visit the sump. The passage here had changed as well. Whereas before there was open passage before the sump, with some nice mud formations, now there were tons of gravel everywhere, reducing the final bit of passage – that I remember as having been easy walking-size – to a flat-out crawl. We saw no sign of the mud formations, either, deducing that they must have been covered in gravel.
So, it looks as though there has been a major flood event sometime in the last year or two that has brought in tons of gravel. Where on Earth did it come from? Did it get washed through the sump from Aygill Caverns? It strikes me as remarkable that so much stuff could have got transported all that way without getting dumped en route (apart from that dumped in the sump-that-no-longer-dries-out, presumably). Any thoughts, anybody?
