Cueva de la Marniosa – Setup

Cueva de La Marniosa (2016)
Cueva de La Marniosa (2016)

One of the objectives of the 2017 expedition is the aid climb of an 80m aven, in Cueva de la Marniosa.  Unfortunately, the aven lies beyond a sump, so divers are required to pass the sump before attempting the climb beyond.  The climbing of the aven is more for the desire to connect to any nearby surface sites, as such a connection would allow teams of non-divers to enter beyond the sump and then support divers at the currently undived sump 2, further into the cave and considerably more challenging for divers to work on their own.

Marniosa lies just up valley of Cueva del Nacimiento, and is probably a feeder into the larger system.  The entrance is a small 1m high fissure in the side of the hillside, where a cool strong draft emits constantly.

Originally the cave was a cheese cave, typical of the area, and used to store the local cheeses, a particularly strong blue veined variety.  However, beyond the old abandoned cheese racks, lies nearly 5km of cave from large dusty chambers in the higher entrance series, to an active streamway at around -230m depth.  Marniosa was heavily explored in the late 70’s by Lancaster University Speleological Society (LUSS), but following a tragic accident, visits become less and the neighbouring Nacimiento cave was proving to be giving up its secrets far more easily.  It wasn’t until the mid-80’s that a team from the South Wales Caving Club (SWCC) returned to Marniosa with the aim of exploring the undived sumps. This was a highly successful trip that not only dived the first sump, but also discovered nearly a 1km of passage beyond, terminating in a second sump pool.

Initially, we wanted to transport some dive bottles to sump 1, ready for the divers, to dive sump 1 later in the week.  A team of 4 assembled with various size bottles attached to their backs and other assorted bits and pieces.  Normally a 45 minutes slog down the track to the cave is required, but now, with the benefit of a 4×4, we drove straight to the cave and only a short 5 minute climb to the entrance was required.

Marniosa entrance 2011
Marniosa entrance 2011

After the initial entrance chamber, the cave quickly starts to descend rapidly via a series of initially small pitches to the impressive Morning Chamber, full of old stalagmites and stalactites.  As we had all been in Marniosa a few times over the years, we didn’t stop to admire the scenery and we continued onto the next large 20m pitch.  The cave had been left rigged from the previous year, so we had no hassle of carrying rope and metalwork to rig the pitches and we all reached this point with ease.  From here the cave changes character again, with large fossil galleries and abandoned streamways.  This is the nicest section of the cave, with lots of interesting formations and pleasant passage.

Typical passage, Marniosa 2016)
Typical passage, Marniosa 2016)

All too soon, the cave changes again, with more muddy passage taking over and we knew we would be approaching the drop into the streamway.  Papoose Pitch, as it is called, is a very muddy affair, with no real clean rigging possible and just a lot of mud to slip and injure something.  At the bottom a series of platform are reached, that lead down via some exposed climbs, into the streamway.  The active streamway makes a nice change from the rest of the cave, upstream in particular containing a lot of passage to a terminal chamber with a number of avens to be climbed.  However, we were interested in downstream, so we set off again.  It’s been a few years since I have been downstream in Marniosa, but I had forgotten how tricky some of the passage is, with high level traverses or exposed climb downs required for most of the 400m between the bottom of Papoose Pitch to Sump 1.  There are 3 pitches in the streamway, again rigged last year, and there was a danger that winter floods might have damaged some of the rope, but luckily the first 2 pitches were fine.  The third one was different.  Not only was it rigged with deviations using maillons (ran out of carabiners), the core was exposed (found this out after I had already reached the bottom of the pitch).  This will need re-rigging when we come back.

Not long after this final pitch, the start of a series of swims marks the approaching sump.  Gear was stashed here while Gareth took a quick jump into the deeper streamway to check out the sump.

A small dive base, Marniosa (2017)
A small dive base, Marniosa (2017)
Gareth swims, Marniosa 2017)
Gareth swims, Marniosa 2017)

Although he was only gone for 5 minutes, it’s a very chilly place in the stream and we were all starting to get cold.  A few jelly beans for energy and we set off back.  The original plan had been to look at some leads upstream but as time was getting on, an exit was preferred.  Progress was slow coming out, and there was some opportunity for photos while waiting to ascend the pitches

Eventually, we exited after 7 hours underground, but still more ferrying trips required, before a proper dive can be launched.