Igue des Tardieux

Once past the narrow entrance, you reach a shaft whose top is bell-shaped, dug into an unreliable fill that crumbles at the slightest touch; 5 metres lower down, solid rock is finally reached. A large broken stalagmite lies wedged across the shaft, whose horizontal dimensions vary from 0.6 to 2 metres, the cross-section being elongated. The bottom is reached at -18 metres in a low room 3 to 4 m in diameter and 1.50 m high. Two flat-out passages follow the room: the first, on the South side, gives access to a concretion-covered chimney 5 metres high, with no outlet; the second, on the North side, will be the terminus of the first visit as it is impassable. Behind the crawl, a small room has on one side a very well decorated chimney plunging into a small gour full to the brim; beside it opens a crawl allowing access to a gallery of respectable dimensions (2 metres by 3). Further on, a beautiful perfectly white flowstone 4 metres high requires a climb and then a descent back to the initial level of the gallery, with the start of a very narrow but well decorated crawl. After climbing the white flowstone, 2 ways are possible: one, staying high, enters a crawl that is in fact the upper part of the joint forming another crawl at its base. These two crawls open into a room 17 metres by 4, for 4 to 5 metres in height. In the middle of the room is the “rock that went splash”: a stratum of the ceiling collapsed onto a bed of plastic clay that was pushed all around into a large wave of clay, perfectly visible; the trace of the ceiling's detachment not being detectable, one may think it is a fairly old fall and that the room has therefore not been reworked since. In the end, this is a small cavity (85 metres of passage, for a depth of -23 metres), very endearing and surprising for certain dimensions (P18 and room 17 metres long) that one would not expect to find in this sector of the causse.

The walls are well covered in concretion and many calcite crystals reflect the beams of our lights. The chimney of the small room is very well decorated with sparkling flowstone and draperies. A splendid floor covered with brown calcite cauliflowers will, alas, have to be partly sacrificed in order to continue.

From a hydrological point of view, the causse located between the cavity and Saint-Pierre-Lafeuille has a few shallow dolines, absorbing the rainwater of this sector. Two springs are located in the combe des Tardieux: one, directly below the igue des Tardieux, about 50 metres lower, and a second at the bottom of the combe; they are both developed, which means they are perennial even if low-water flows are weak. In the igue des Tardieux, infiltrations are found at the level of the Salle des Draperies and especially at the bottom of the terminal room where they disappear through the absorption shaft. One can therefore consider the hypothesis that the igue des Tardieux belongs to a network feeding the springs from the dolines of Saint-Pierre-Lafeuille, a hypothesis that cannot be confirmed given the low flows encountered (infiltrations).

Position the surplus gear well (rope and ladder, since the shaft was not rigged for jumaring) out of reach of stones, because it “parpines” hard on the ascent or descent of team members. At the other end of the large room there is a small water inlet high up, coming from a clogging overhanging a terribly unstable absorption shaft; a start of digging at the bottom of the shaft, in a very airy and shifting clogging, does not allow any penetrable continuation to be seen, and given the danger of collapse, we give up. Next to the block, a shaft stops us for lack of gear (shallow, but a real soap bar), likewise for a narrow squeeze at the top of a shaft, near the entrance of the room. A fourth descent proved necessary, in March 89, to finish the cavity (Milhas Marie-Thérèse and Claude, Zanon Bernard and Josette): complete survey and descent after digging out the 2 shafts 4 metres deep, both opening onto the same “joint” (or rather a vertical passage between the blocks making up the floor of the room); this passage ends in strictly impassable narrow squeezes in the direction of the nearby absorption shaft.

The igue des Tardieux is located in the marly limestones of the Upper Kimmeridgian. The first 5 metres of the igue des Tardieux are dug into a very unstable fill (slope castine and mixed blocks). The walls are then relatively sound despite a tendency for sometimes imposing blocks to fall, made up of portions of strata detached from the original rock bed. The floor of the cavity is moreover composed in large part of collapsed strata of very variable dimensions.