Matienzo '93

There are now over 161km of explored cave passages around the Matienzo depression. About 140km of this has been explored and surveyed by the British expeditions which are now completing their 23rd year. Despite over 70 people visiting Matienzo during the summer, 1993 was not a year of great discoveries, rather interesting extensions and connections, adding to the knowledge of the area and raising more questions for the future.


Cubija

Area Map

The major finds of the 1993 expedition were explored under the Cubija valley where Torca de Regaton was more than doubled in length and linked to another entrance. Last year, Regaton was abandoned at an incompletely explored boulder choke heading west into the unknown, with a number of leads also heading off to the south. This year the entrance pitches were tackled up and the southern leads off Skye Passage entered through a short crawl into instant glory.

The route followed a stream passage up past several side passages and avens to a sump which was immediately lowered to a form a duck. This led the explorers through to more stream passage and the base of a short pitch with passage visible at the top. Opposite was a large sandy ramp, climbed to a maze. Later trips into this area found a complete dog skeleton in a passage named Lassie's Last Stand and a plastic toy horse, which prompted a visit to the Cubija farmhouse to enquire whether anyone in the extended family recognised the toy or remembered into which rubbish filled shakehole it may have been thrown. Nobody recognised the horse, but the finds added enthusiasm to the re-exploration of El Cubio, an open hole in the streambed out of which blew a "hurricane draught".

Cubio was explored and extended between unstable blocks, tight squeezes and honeycomb sandy limestone with sharp corners until a washed limestone tube was entered, stopping at the head of a short climb. This was dropped to a canal and a tight pitch head which was promptly enlarged and dropped to another pitch of 6m which dropped onto the Ramp series of passages being explored in Regaton.

The creation of the Sistema de Cubio-Regaton has provided a much less time-consuming and technical entrance although, according to one old-timer, Cubio's a "sharp, grotty, miserable cave that we wouldn't have bothered with in the 70's".

The western extensions were forced in BOS choke through some barely perched boulders to a large chamber with nice stal. Across the chamber the route continued for 250m into a massive draught, temporarily ending at a 15 x 15m chamber with abundant boulders. The next trip took the new Cubio entrance and "walked through" to the previous end, dropped a short pitch and entered easy going to a right hand turn ending at a 2m diameter eyehole with the wind powering through. The cavers looking through the Surprise View were sitting at the top of a steep mud slope down to a large trench with a similar mud slope descending from the opposite wall. The passage did not live up to its promise, going deep with lots of mud, chokes and a couple of sumps. Running water can be heard and it may be possible to dig. This area is the deepest point reached in the system and, at 160m altitude, the water would have to resurge outside the depression, beyond Alisas and Cobadal.

Seventy metres back from Surprise View, another surprise was the discovery of a small gap which led to a washed, black limestone passage and a boulder-floored route some 4m wide and high. This entered Frog Passage, where walking and easy going stopped at a "bottomless" blue pool after about 400m. The next trip found that the pool was a deep wade which developed into a canal, averaging some 3m width. This continued for about 500m with a few ducks and small rock bridges providing a little interest. The canal ended at a walking-sized stream passage with formations and ended at a boulder choke which needs pushing. A 40m ramp off to the north was decorated with helictites and other fine formations.

Two hundred metres beyond BOS Choke, a ladder was used as a skipping rope to lasso a natural belay at the top of a climb. Here, muddy crawls and chambers eventually entered a draughting, bouldery calcited grotto which should dig. This area is one of the better leads for 1994.

The downstream end of the eastern river was also visited, various boulders and digs removed, but no significant extensions made.

The surveyed extensions to Cubio-Regaton measured over 3.8km, providing more than half of the total passages entered this year and raising more questions and leads to go at in the future.

It became obvious, during the explorations in Frog Passage, that the system was heading towards Sima del Picón. This contains a major passage, between 20 and 30m wide, floored with giant boulders, which was first explored by Spaniards in 1967 to a length of about 500m. A couple of trips during previous summer expeditions had failed to extend the cave, but with the lure of open passage nearby, a stal grill with a faint draught was smashed through and new tunnel entered at a high level. The well decorated passage continues under a false floor to the large sandy-floored main junction. To the left a series of phreatic passages and a very steep hading rift were entered; straight on proved to be the route forwards leading to a sandy slope and a 21m pitch. At the base a steeply inclined sand and boulder slope descends to a narrow rift, through a couple of digs to a 10m high and 12m diameter chamber with a boulder floor and some interesting mud formations. The draught comes from a mud covered slope and a small slot which was dug to another chamber and passage which ended at a complete mud blockage after a very nice sediment bank and a cracked mud floor. The deepest point in this series is 87m below the entrance. A route upwards from the base of the pitch passes under large formations to an 8 x 4m chamber with a possible dig at one end and a climb at the other. A lined traverse over the 21m pitch has a tricky move half way round and then enters a well decorated passage to a draughting boulder choke in two passages. A descent down a steep boulder slope leads to a mud climb in a mucky, large chamber which has not been done. This series has lots of pretties including huge helictites.

Picon survey (from 1994)

Picón finished with a length of more than 1.2km and a number of draughts still to look at. In the end the cave didn't link with Cubio-Regaton or with Torca de Lastrilla, both of which appear close on the maps.

Having extended 3 out of 3 caves in the area it seemed a good idea to re-explore and re-survey Torcón de Cubija, also well known and thought to be finished after Spanish and British explorations. Despite a good poke about this year that does appear to be the case although draughting digs and an aven appearing to intersect Torca de Mostajo means that a return will have to made next year.

During our Easter visit cave 415, the supposed "back door" to Mostajo, was extended through a stal blockage into crawling until the way on was blocked by a stal with a bat hanging from it. This summer the bat had gone and the passage was extended to 70m, containing probably the second best set of helictites around Matienzo - the best are in Mostajo.


South Vega

Across on the south side of La Vega the DCC were busy using their superior digging technology to remove large boulders out of site 495. Against a cliff face which slopes back into the hill, the dig is now 10m deep with a short crawl out of daylight. The draughting way on still appears to be down and needs pursuing as the feature is at the same level as the major level in Torca de Coteron, part of the South Vega System.

Underground in the South Vega System, a team traversed upwards, over a 70m pitch across the top of the loose Giga Hall and into a fine continuation heading east, running parallel to the sump and back towards Mega Hall in old Reñada. The 250m extension included a 100m x 30m chamber and some incredible gypsum formations.

In Sanatogen Passage in Reñada a small amount of significant passage was discovered, incompletely explored and heading towards a recent extension in Torca de Azpilicueta.

Cueva Valline, a site which could possibly connect with the South Vega System, was largely explored by the Matienzo Expedition in '89. Unfortunately, the cave was outside of our permit boundaries, a number of Spaniards were unhappy, and we were not granted permission to cave in the following year. In 1991 relations with the exploring group were restored when we were allowed to video in the high levels. This year a joint diving / pushing trip was undertaken and Phil Papard dived in the downstream sump. A nearby boulder choke was poked at and upstream avens were bolted. We agreed to another trip after the Spaniards left and, rather embarrassingly, Pete Eagan slipped through the boulder choke and into a chamber with passages going all over the place. The cave was left at this point and we hope to arrange a joint trip in the near future.


Four Valleys System

Another entrance to the Four Valleys System (40km long) was almost discovered in Riaño. It was felt that an easier way in might speed up explorations at the end of Cueva Uzueka. A passage in Cueva Riaño parallels the entrance series and heads back to the surface with some evidence of surface debris including water worn pieces of red pottery. A team visited the bouldery, draughting end of this passage and lit small fire of paper, rubber and wetsuit bits. The thick smoke emerged on the surface through a large surface choke and out of the entrance of Dormouse Cave which, 30 minutes earlier had been pushed 70m to a constriction in a low stream with water worn pottery. The connection hasn't been pushed but may just provide an easier entrance.

The more exciting caving in the Four Valleys System occurred in Cueva Uzueka at Gour Inlet and the Astradome. The former was bolted up 12m, just short of entering a passage. Progress was stopped by poor rock. It may be possible to enter the inlet by a different route. The Astradome is a 30m diameter aven which was found to rise over 101m a number of years ago by using a helium-filled weather balloon and a piece of cotton. A dribble of water down the middle suggested that a passage might exist at the top. Needless to say, strong lights and flares didn't illuminate the top. This year, Mark Wright and Tim Allen spent 10 hours over 2 days bolting up to within 4m of the top. Progress was stopped by a bed of sandstone, but an inlet was seen, and it may be possible to maypole off a bolt and into it.


Fresnedo

The other major aim of this years expedition was to push Cueva de Fresnedo. Last year the cave was extended by 4.7km and hopes were high for significant extensions during '93. But only one trip went to the end and extended it by little. Most work and tidying up of loose ends was carried out in the entrance passages where over 640m were surveyed. In the Knotted Rope Series various pits were dropped and climbs bolted, suggesting that this section of the hillside is more space than rock.


Other sites

On Muela, Torca del Triveno was linked through to Sima Levantada and 220m surveyed. Other shafts were explored, but the big one down to major horizontal development is still elusive.

Small finds included 170m of 20m wide passage in Cueva de Hoyo Verde at Llueva where a well decorated passage revealed pottery, much charcoal and a musket ball. The farmer was quite possessive of his cave and insisted that it was much longer than it was - his dad had been down for a kilometre.

In La Secada, shaft 715 was opened up near 415 and described as a Yorkshire pot some 70m deep. The Misty Series aven was visited in Torcón de Calleja Rebollo (Toad in the Hole) and a small draughting dig beyond was pushed through to another possible dig heading north into the unknown.


Stal dating

Another scientific project was started this year. A number of large, dirty stal were removed from Cubio-Regaton, Fresnedo, Torca de Azpilicueta and Cueva del Agua. Steve Openshaw is carrying out a magnetic study of each, using a SQUID magnetometer to obtain secular variation data, and dating using uranium-thorium dating techniques. The results should allow the construction of a composite secular variation master curve for the area.


Socialising

One of the Camargo caves (Caliente-Frio) near Santander was visited by invitation of the Grupo de Espeleologia e Investigaciones de Carbollo/Rada and some surveying and pushing undertaken, helping out with an area study financed by the Camargo town hall.

Superb though the Matienzo caves are, they were put into a national perspective when some of the expedition visited the 100km long Ojo Guareña, near Espinosa. A guided tour led the 18 member team through some 5km of passage in 5 hours, with talks about the geology and history of exploration. A great day out which we hope to repeat next year.

The campsite at the back of German's bar was improved in 1992 with the building of a shower and toilet block. This year the architects were prowling around the back of the bar: the intention is to add on a single storey restaurant. What will '94 bring?

This year was also the 80th birthday of Le Docteur - Doctor Castin - the leader of the French cavers who were particularly active in Cueto-Coventosa and other caves in the Asón during the seventies and eighties. While enjoying a joint piss-up in the Asón gorge some fifteen years ago Big Jane fell on him and broke his ankle. We've seen very little of the French since. During his outdoor birthday party with food, and wine flowing freely, the doctor was presented with a photo album of his caving exploits by the mayor of Chablis. A couple of pages were devoted to his fracture and trip to hospital which now seems to amuse him. Another international incident healed over.

The hospitality of the locals continues to make our stays most enjoyable. Our thanks go to the Ghar Parau Fund committee and NCA for administering our Sports Council grant and to the Spanish caving authorities for granting permission for three visits during 1993


References

1: Matienzo '92 in Caves & Caving 58, Winter 1992

2: Matienzo '89 in Caves & Caving 49, Autumn 1990

books, journals and expedition reports etc. relating to Matienzo


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