OUCC Proceedings 13 (1991)
|Proc. 13 Contents.
Martin Laverty and John Wilcock
The following hypotheses about the caves of the Dobra, Tabardin, Casano and Cares catchments have resulted from dowsing work carried out by the authors during the 1989 Juracao Expedition. Dowsing for the detection of caves and underground watercourses is a controversial subject, which it is not the place to discuss here; the authors profess themselves to be agnostics about the technique, but maintain there is a case to be answered. It must be regarded as a physical effect, detectable on site, and in no way a mystical technique (the authors, being scientists, can entertain no other considerations). Since the physical effect must pass through many hundred metres of rock, a probable explanation is that there is a magnetic effect which can be detected by some humans, perhaps in the same way that magnetism can be detected by homing pigeons, bees and dolphins. The results are presented without prejudice. Time alone will tell whether the results are confirmed by exploration or dye traces.
The main inflows to Lago Enol are a small spring from the southeast and a major inlet from La Porra de Enol on the southwest which enters at the bathing place, where colder water can be felt. A stream outflow under the road on the northeast soon sinks, reappearing at the base of a 100m cliff on the southern side of the base of the polje Vega de Comeya. The stream then meanders through the alluvial sediments which resulted from the dressing floors of the Minas de Buferrera, finally sinking on the northwest. Indications are that the flow is then north, where there are many shakeholes, and the final rising may be in the Rio Tabardin.
Inflows to Lago de la Ercina are from the southeast (probably two separate systems). One results from sinks in the floor of the polje La Vega el Pare to the north west of Fuente Escondida, flowing north and then west. A parallel system starts from a shakehole just to the south of the Ario path, flowing north and then shortly west. Both enter on the east side of Ercina. Outflow from Ercina is on the southern tip, under the hill to the polje Las Reblagas (this was proved by dye trace on the 1961 expedition). After meandering across the floor of the polje, the stream then sinks again. It is thought to proceed northwest via Pozo de la Vega el Forcan, west and then north to the vicinity of the Las Rablagas sink.
Another tributary to the Dobra catchment is the Rio Redemuna. It is proposed that Ridge Cave at Top Camp proceeds west-northwest via Cueva del Frieru and Cueva del Viento to several risings in the Rio Redemuna, which again sinks before proceeding northwest to the Dobra.
The most interesting results concern the F20 and Jorcada Blanca caves at Top Camp. It is proposed that these proceed due north via Vega de Aliseda (where there are many shakeholes), under the impressive Jou del Agua, through a sequence of deep shakeholes and then to a large relict cave entrance at the western end of Las Fuentes. The course then swings west, going much deeper and joining Cueva del Osu, then north-northeast to Las Bobias, passing under the Ario path 200m west of the houses. The course then proceeds north to the resurgence at El Hoyo La Madre. The "Bobias Spring', 300m east of the houses, appears to be a separate system much closer to the surface.
The Pozu del Xitu system appears to have a previously unknown inlet at the extreme western point of the cave. This immense system has the unfortunate effect of masking much of the Ario area by a blanket reaction. Xitu is thought to enter Culiembro via the southwestern inlet.
The Pozo del Ojo de la Bruja (2/7) is thought to have two main inlets draining about 2 sq.km within the circle of peaks Pico Gustuteru, Cabeza del Burro, El Regallon, Cuvicente and Jultayu. It is not thought to have a contribution from the Top Camp caves. The two inlets join, then proceed to a collapse depression on the southern side of the Valle Extremero, heading 50o. Near here there is a small cave (53/5) about 10m below the surface, which however is on a different heading (30° ) to 2/7 and may be a high-level feeder to Xitu. There is also the small "Black Streak Cave' on the northern side of the valley, which seems blocked, but which lies directly over the 2/7 streamway, here about 30m below the valley. It is predicted that 2/7 passes over Xitu and continues northeast, before swinging north west to 7/4 [see OUCC Las Brujas Expedition Final Report]. A feeder from Vega Maor via Cabeza Muxa joins here, and it is predicted that the combined waters of 2/7 and Cabeza Muxa proceed east to an unknown western passage of Culiembro. On the surface above the proposed juncion of the Culiembro passages is a large cave at Posadorio. There are also large tubes visible at this level across the Cares Gorge in the wall of the Central Massif.
Another inflow to the Cares is Forfau de la Vina, carrying from the Central Massif down a prominent rift from the east.
The Caves of the Ario Depression
A series of small but interesting caves occur in the Ario area. Unfortunately the southern edge is masked by the blanket reaction of Xitu, and so neither the source of one of the main inlets ("Dry valley inlet') nor the destination of the main outflow is known (probably Xitu). There are several inlets, at Cabeza de la Forma, and two separate series of springs, now dry, which are very near the old houses and sheepfolds of Ario, and presumably the reason for their location. There are several deep shakeholes, one of which contains a snow plug, the source of water for the Ario camp when the Ario spring dries to a trickle.
It is hoped that these predictions prove interesting, and perhaps prove an inspiration for future explorations. It seems clear that 2/7 is only about 30m below the bottom of the Valle Extremero, just above the beginning of the steepest bit above the trees, and digging in the collapse depression mentioned might prove useful, or perhaps an entry may be made via the two small caves discovered there. This might prove preferable to future pushing in the interminable chokes of the streamway. Alternatively, an entry might be gained via 7/4, close to the predicted junction between 2/7 and Cabeza Muxa.