OUCC Proceedings 13 (1991)Scientific work in the Picos de Europa |
Proc. 13 Contents. |
On the 4th and 5th August 1990 Paul Mann and Claire Lindon carried out a surface survey along the approximate line of the cave. The objective was to locate the cave relative to the surface, with the following aims:
Surveying was carried out using methods identical to those used for the underground survey [2]. A 30m tape, sighting compass and clinometer (Suunto type readable to a 1/2° ) were used and alternate legs were surveyed in the reverse direction ("leap-froggingmm) to reduce systematic errors. In all 90 legs were surveyed and a further three landmarks were located trigonometrically. The results were within 1% of those of Gerhard Niklasch's [3], the location of the 2/7 entrance differing by 2.6m horizontally and 1.8m vertically well within Gerhard's quoted accuracy of +/- 2.8m horizontally and +/- 4.0m vertically.
Further topographic information was taken from a 1:25,000 map of the Western Massif, Picos de Cornion [4], and magnetic North was taken as 3° 25' West of grid North to correspond to the 1989 survey of 2/7 used to compile the combined survey. Additional survey data was added from the 1990 survey.
The combined survey shows the cave to run obliquely under the cliffs on the South Eastern side of the North East ridge of Jultayu (known as the "Green Ridge"), before cutting across the head of the Trea valley. Choke Egbert is very close to (within 70m to the south of, and at a depth of 290m below,) the prominent surface collapse, Huerta del Rey. Given a general dip of 80-85° South East for geological fractures governing the cave development, it appears that these two features are related.
Points surveyed to include:
Skull Cave, which lies directly above the huge London Underground passageway, and hence has great potential of providing an alternative entrance. However, due to the vertical separation between the two, it would be foolish to predict where Skull Cave will connect with 2/7.
A strongly draughting boulder ruckle on the Green Ridge, which lies 125m to the North West of the cave;
5/10, which lies 220m distance North of the cave.
Three small caves in a rift in the North West corner of the large depression, Huerta del Rey; these unfortunately have no obvious leads.
29/5 was not included in the survey, but lies about 100m further North than 5/10.
Table 3 Shows the UTM grid locations of a number of points in the cave together with nearby surface features, and the vertical separation between the two.
Location Eastings Northings Altitude Vertical
Separation
Egbert 344,867.8 88,667.9 1045.1 -
Base of Huerta del 344,898.6 88,735.4 1335.0 289.9
Rey
Brim of Huerta del 344,892.9 88,699.9 1367.6 322.5
Rey
Nearest point on 344,910.0 88,625.0 1350.0 304.9
Trea Path
Colostomy Climb 344,790.6 88,637.1 1044.2 -
Trea Valley 344,750.0 88,600.0 1370.0 325.8
White Inlets 344,660.8 88,632.4 1102.1 -
Trea Hillside 344,660.0 88,630.0 1395.0 292.9
Primula Point 344,506.5 88,478.4 1049.8 -
Trea Hillside 344,625.0 88,500.0 1475.0 425.2
Paddington Choke 344,440.5 88,469.3 1135.4 -
Green Ridge 344,406.8 88,550.7 1611.0 475.6
Other points
surveyed to
2/7 Entrance 343,978.2 88,012.7 1848.1
Skull Cave 344,177.0 88,197.6 1821.8
Jultayu 344,220.4 88,014.8 1941.5
The Primula Point campsite is at a depth of 425m. The closest the far reaches of the cave come to the surface is a depth of approximately 300m in three places: Choke Egbert, Colostomy Climb and the White Inlets in Soup Dragon. This distance may be reduced in the latter two cases by climbing. These points plus possibly Paddington Choke (at a depth of about 475m) would be suitable places for radio-location to check on, and increase the accuracy of, the cave survey.
The survey suggests that a search in the general area around Huerta del Rey may provide a lower entrance near to (or better still beyond) the present limit in 2/7. It is likely that any entrances on the slopes of Jultayu or around the Green Ridge will, if passable, connect with 2/7 whilst those in the area of the Jou de la Cistra and the Trea path up to where the path up Jultayu branches off are likely to connect with Sistema del Xitu (for example 3/5 and 12/5 [5],[6]).
[1] Macklin, R. O. (1984) In: Caving Practice and Equipment.(D. Judson, Ed.) pp175-179. David & Charles, London.
[2] Ellis, B. M. (1976) Surveying Caves BCRA, Bridgewater.
[3] Horsley, D. Roberts, S. G. Arthur, J. and Taylor, R (1989) Oxford Univ. Cave Club Juracao Expedition Final Report.
[4] Adrades, M. A. (1990) El Cornion mapa-guia del Macizo de los Picos de Europa. Oviedo
[5] Stead, W. (1986) Pozu los Caracoles (3/5): Description. Proc. Oxford Univ. Cave Club 12 11-13.
[6] Roberts, S. G. (1986) Pozu la Cistra (12/5): Description. Proc. Oxford Univ. Cave Club 12 5-8.
Paul Mann and Dave Horsley