Cave exploration around Matienzo during Easter and summer 2000
The Matienzo explorers enjoyed summer weather for most of the time at Easter
and in the summer. About 5.4km of passage were surveyed, split more or less
equally between both periods, including nearly a kilometer of resurveying
in the Catalans site VT62 (1176) and 2250m
in the new site Torca de Papá Noel
(1471). Various groups augmented the usual
expedition members including Adolfo, Jordi and friends from the Espeleo Club
Tortosa and AA. EE. T de Valls, Santi Urrutia from ADES (Gernika) and members
of Liverpool University Potholing Club and
Sheffield University Speleological
Society. The number of sites on the list of speleological interest increased
by 133, giving a total of 1593 with over 223km of cave passage. With the
recent removal of the GPS inaccuracy, we were able to start repositioning
some sites in their correct places on the maps.
In summary, and described within the various cave areas, the highlights of exploration were as follows.
Four Valleys System
At Easter, a substantial length of stream passage (264m) was entered up a 15m aven at the end of Shrimpbone Inlet in Cueva Hoyuca (0107). The two long trips at the far end of Hoyuca found the passage dividing and ending at a number of avens. Some unexplored passage remains to be pushed. During the summer, work was concentrated around the entrance passages where the unexpected, low level Wildlife Series was entered down a pitch, 10m from the squeeze into the start of Quadraphenia on the main route. About 300m was surveyed here, bringing the total length of surveyed passage in the Four Valleys System to 42853m.
Site 1496, in an interesting position over Hoyuca, is a draughting low crawl and this was partially excavated in a wide bedding.
The main road improvements through the depression have cut back into the limestone in a number of places, exposing a number of interesting holes. The road-side dig, site 1452, was excavated at Easter to the head of a 70m pitch which dropped into Cueva Bollón (0098).
Upstream exploration was attempted during both Easter and summer, but the water levels appeared too high. A prolonged period of dry weather is required to make progress through the aqueous boulder choke. This top entrance will be preferable for attempting to extend the cave rather than the old, bottom entrance route that needs diving gear to pass three small sumps.
Just 100m up the road from 1452, "The Road Show" (site1506) was entered at the end of the Easter expedition. This 50m segment has good formations and a possible dig.
Cave of the Six Shafts (site 0543) was finally relocated and partially re-explored after being "lost" for 23 years.
North Vega and El Naso
Cofresnedo (site 0065), a prominent entrance and large passage on the northwest side of El Naso, has been known and probably used since humans first encountered the enclosed depression. Various artifacts and human remains have been found in the cave and Spanish archaeologists now have permission to excavate in the cave. The cave was inspected in the summer so that digging could start in the autumn.
A fair amount of prospecting work was carried out on El Naso and various new and old holes were descended. There are some areas where complete re-exploration and re-positioning will be needed as the GPS is showing up descrepancies.
Site 1572 was first spotted while sitting outside the Vega bar looking at the southern side of El Naso. High up in cliffs above Cueva Rascavieja, the prominent entrance seemed to be rather difficult to get to. As it turned out access was via an easy climb down a stepped limestone pinnacle. The cave turned out to have a 5m high and 3m wide entrance, with phreatic passage rising to a crawl and choke after 30m. To the east, a number of small animal shelters all choked.
Some digging was carried out in sites 0813 and 0815 where good draughts promise a link with the North Vega System below.
South Vega and Seldesuto
Extensions in Arenal (site 0035) were surveyed and pushed beyond the Foam Dome over Easter, Whit and the summer, working with the cavers from the Catalan caving groups.
A number of sites were explored on the South Vega hillside during Easter and a couple held exciting prospects for the summer (1338 and Torca de Papá Noel 1471). As it happened, site 1338 was tackled up but not pushed and efforts were concentrated in Papá Noel. Over 2.2km was surveyed in this 225m deep system. The entrance series lies over the hub of the South Vega System where Torca de Coteron links with Reñada and it was thought at one stage that a giant boulder choke could provide a link down into Coteron. However, the cave has headed west and is apparently very close to the Coffin Levels in Torca de Azpilicueta. The cave has some very large and impressive sections and may eventually provide a number of routes to different sections of the South Vega System. There are a number of leads to push.
More prospecting and shaft descending was carried out during the summer. For example, site 1538 has a shaft and cave entrance into a small chamber with a descending rift that chokes. In another hole, 1542, 30m of stooping and crawling ended in a low chamber with gour pools.
One of the draughting digs up the Azpilicueta track at Seldesuto was continued and another couple of promising roaring holes were discovered only 60m away.
At Easter, Martin Holroyd carried out a couple of dives in upstream Vallina - breaking surface into a short canal at the end but then meeting the next sump. 230m was surveyed.
In Cueva Coquisera (Cueva Codisera - site 0039), the top shaft entrances were finally surveyed though to the main cave, but this exposed a glaring error in one of the original (British) surveys.
Cueva Abono was linked to a top entrance, 1470
Cueva Tizones (78) was "finished" at the high level, adding 156m to the length.
Jivero 1 was dived through and linked to site 246.
At Easter, Sima de la Garma de los Trillos - site 1176 or VT62 was explored and resurveyed after an invitation from the Catalans. The cave is draughting strongly and in a prime position to link into Vallina or the South Vega System. In the summer, efforts were diverted elsewhere and this site remains to be pushed.
In Torca de Reguilon (site 0046) a bolt route was started part way down the 70m entrance pitch to a possible passage.
In Cueva Copudia (site 0265), close to Torca de Coteron, a descending rift was explored along a joint at the back of this very large fragment. At one point, a draughting, 30m deep but very narrow joint was seen.
In site 311, a draughting dig was pursued above a previously exposed 30m pitch eventually leading to the route dividing at a flake. Above site 311, site 1512 involved a crawl to a pitch into a damp chamber where the water disappears down a narrow meandering passage that needs enlarging.
Cueva de los Cantones (site 865) was explored in 1991 with some going leads in its length of 1716m and 285m depth. This year the site was "given" to the Catalan group to explore. After tackling up the pitch down through the main, loose, bouldery chamber and returning the following day, they found that the rope had been cut by a falling rock. Enthusiasm dropped to zero and the Cantones "gift" has been returned!
Below the Cantones depression, Cueva Adillos (site 0034) was rediscovered and explored but the new site 1514 - an old phreatic fragment - was explored through 3 entrances in 2 to 3m high and wide passages. In places throughout the 112m length, the bouldery floor deposits had been stacked on the side and fragments of old pottery were found.
Shaft 320 has had a chequered history since 1981, from being a 90m undescended pitch to a 4m climb to a draughtless choke. Last year and this saw the site finally being pinned down, lumphammered and explored. Despite enticing noises from falling rocks, the shaft turned out to be only 27m deep.
Various small shafts were explored and site 169 resurveyed. In two "new" areas in or near the woods a kilometre down to the east of Mullir, some interesting draughting digs were investigated. Nearby at site 1570, 40m of walking-size passage was entered, and Mistletoe Pot (1575) was explored down an 18m pitch into a 16m pitch lined with soft calcite with a low, well decorated crawl half way down.
Once more, there were more questions raised for next year than were answered in this one.
The Asociación EcoCulturas (http://ecoculturas.cjb.net) held a series of meetings over a fortnight involving the villagers and trying to understand and preserve cultural activities and the countryside around Matienzo. As part of their fact finding, the group asked to be shown a variety of caves. On one afternoon the group was introduced to the geomorphology of the Matienzo depression, taken through Cueva Jivero 2 with its population of crayfish and shown Cueva Molino as an example of a old and large cave sink also with a level of calcited bones. On a second afternoon a large group visited La Cuvia as an example of a cave currently being used by a farmer and as a typical Matienzo dry "tunnel"; the second site visited was Las Grajas, a site excavated by Spanish archaeologists, with pottery and charcoal in hearths.
We were welcomed by Pablo at Bar German and the expedition is grateful for the camping facilities and the use of the restaurant for computing and drawing up.
The list below shows links to those 232 sites which were extended or newly discovered over Easter and the summer, or which have had surveys updated, entrance photos added or entrances repositioned with a GPS.
A quick trip in October updated or discovered the following sites:
0058 0070 0202 0204 0224 0496 0534 0535 0536 0561 0623 0965 0966 0967 0968 1594 1595 1596 1597 1598 1599 1601 1602
A trip in December updated or discovered the following sites:
0059 0065 0071 0081 0085 0086 1600 1603 1604 1605 1606 1607
Juan Corrin, September, November, December 2000
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