OUCC Proceedings 7 (1975)
|OUCC Proceedings 7 Contents|
This cave is situated on the steep, gorse-covered hillside above the gorge leading from the mouth of the Cueva de Tinganón, which appears as a tall narrow cleft creating a dark vertical gash in the green hillside across and higher up the valley. Like Tinganón the cave is an active resurgence and an approach from below seems to be ruled out by the mossy cascades which the stream flows over down the gorge it has created on its way to the main valley. The approach from above is best described as 'super-severe' involving, as it does, leaving a good, gently graded path, well-trodden by the local campanological cows, to plunge through extremely prickly gorse, over slippery grass and occasionally limestone outcrops with various varieties of snakes, the whole thing being at an average angle of at least 45 degrees. Changing into wet suits on a slope of this nature requires a technique of its own, but one is compensated for the problems by the fine view of the estuary of the Rio Sella and of the surrounding hills.
The cave is entered via a 12m pitch into the gorge leading from its entrance, a rock outcrop providing a good belay, the ladder hanging free, except at the top,& providing a good climb. The entrance passage is large, high, straight and provides a refuge for bats, as was observed during the surveying trip. The cave has been used in the past for water supply, a metre high dam having been constructed with a, now broken drainpipe leading from it to the entrance. This pipe sometimes carries all the caves water, but the water level fluctuates considerably behind the dam so that, on our first visit, there was a distinct stream flowing down the lower, smaller of the two parallel passages leading from the dam to the large entrance passage, where a large pool had formed, while, on a later visit, there was no pool and the water was scarcely up to the level of the drainpipe at the base of the dam ( much to the delight of the person who had been detailed to go and lower the level of the water behind the dam[ This latter measure had been decided upon because the water impounded emerges from a sump which we at first hoped may only have been due to the artificial raising of the water level by the dam, because stalactites were observed to be hanging down into it. The later visit proved the theory to be valid, but only another 16m of deep stream passage were discovered before a very definite sump once again barred our progress. An odd feature of this deep water passage is that the floor drops 1m vertically to impound the water.
The way on is along a higher level passage which starts where the depth of water behind the dam suddenly increases due to the sudden drop in floor level. This passage is well decorated and generally in the nature of a rift passage, the floor being covered by flowstone and old gours. The route starts of f completely dry but the number and size of pools increases towards the end, the level in pools at the end being the same as that at which calcite deposits have formed around the pools walls while the level is markedly below this at intermediate points in the passage. The passage ends with several deep pools and a couple of short climbs. Vigorous efforts at extending the cave by following the main line of the passage and by traversing in the roof of the rift met with no success.
Spaniards, presumably the builders of the dam, have explored the cave to within at least 50m of the end, as is evidenced by their inscriptions on flowstone at two points in the passage above the dam. The nearer of these records visits in 1916 and 1920 whilst the further, just before a chest deep pool, the exit from which is not obvious without getting wet, marks a visit in July 1922. These later explorers appear to have had to break through a calcite barrier in order to continue and similar signs of enthusiasm are to be seen above the dam, where a rather inadequate set of steps has been cut up a wall to reach a small extension. It is a great pity that we could find no references to these explorations, the use of the water, the need for a dam quite a long way inside the cave, or even the Spanish name for the cave.
Several possible new entrances were found along the coastal ridge towards Nueva 1975 and a resurgence - short and blocked - was found at Santianes to the south of Llovio. This village has a good path leading up to a hamlet above Cueva Tinganón top entrance (Cueva Negra in Cox et al 1972) and this is the recommended route to Cueva Negra (Cueva Lledales in Cox et al 1972) and any caves further east since the walk is easy and avoids undergrowth. There is little doubt that much cave is concealed in this area where water is concentrated on a sandstone ridge which drains into poljes at the junction with the adjacent limestone ridge and it is to be hoped that a new cave will be found which does not end so frustratingly as Cueva Negra.
[ Note by Martin Laverty 2004: rediscovered by Grupu Gorfoli and resurveyed by a Portuguese group - as reported in the Asturian Caving site. It is now known as Cueva Pixuacu, but they also retain Abseil Cave: http://www.espeleoastur.as/esploraciones/pixuacu/pixuacu.htm]
Some photographs were taken in this impressive cave in 1973 but no new discoveries were made. A survey has since been carried out in 1975. Discovery 1972 Report. 1975 Report.
This is a large influent cave reached after an hours hike that involves descending perhaps a hundred metres into a steep sided valley and then ascending again, there being no roads in the immediate vicinity of it. The cave lies in a polje, the drainage from which runs against a steeply dipping limestone ridge. The entrance is typical of many Spanish caves, being vast with hanging roof pendants, and bearing all the signs of frequent occupation by cows. This rapidly leads, however, into a narrow streamway into which there are no signs of these bovine speleologists having penetrated.
The cave consists of vadose development along the line of a fault. There is a fairly regular orientation of the streamway which follows the simple linear structure of the fault closely. The average width of the passage is from 1 to 2m, the height varying between 2 and 7m. Occasionally one had to crawl below or squeeze past curtains hanging from the walls, but it was usually possible to walk upright. There is one free climb before the pitch which is followed by another of about 2m. The pitch marks the limit of the 1972 preliminary expedition and descends l5m, with a small waterfall flowing over it into a very shallow pool.
After the pitch, the passage continues with little change from its previous character, though its rift-like nature becomes gradually more discernible. The cave terminated in a very narrow rift with 2, or more, metres of water. The rift could be seen to continue and Guy Cox did, indeed, pass this duck-sump with much gurgling, only to be stopped after a few metres by a similar obstacle which was even narrower above water.
The cave is a very simple one for as far as it has been explored. The limestone in which it is formed is massive and completely unfossiliferous. The faulting is clearly shown by the occurrence of thick calcite veining in the floor and walls, accompanied by intense brecciation of the rocks, outlined by the calcite veins.
This cave is situated close to Cueva Negra, about 15m higher and to the right of some bushes. It is completely dry but contains some fine 'Collonade' type columns, amongst other formations. Its length is something under 100m and all passages appear to choke with stal. or rocks.