Igue des Tardieux

Once past the entrance squeeze, one reaches a shaft whose top is bell-shaped, dug in an unstable fill that crumbles at the slightest touch; 5 metres lower down, solid rock is finally reached. The horizontal dimensions of the shaft vary from 0.6 to 2 metres, the cross-section being elongated. The bottom is reached at -18 metres in a low chamber 3 to 4 m in diameter and 1.50 m high.

Two flat-outs follow the chamber: the first, on the south side, gives access to a concretion-covered chimney 5 metres high, with no continuation; the second, on the north side, was the limit of the first visit because it is impassable.

Behind the crawl, a small chamber has on one side a very well decorated chimney plunging into a small gour full to the brim; beside it opens a tube giving access to a passage of respectable dimensions (2 metres by 3). A few meanders further on, one reaches a splendid floor covered with brown calcite cauliflowers, then the foot of a beautiful perfectly white flowstone 4 metres high, which requires a climb and then a descent back to the initial level of the passage, with the start of a very narrow but well decorated tube.

After climbing the white flowstone, 2 routes are possible: one, staying high, enters a tube that is in fact the upper part of the joint forming another tube at its base. These two tubes open into a chamber 17 metres by 4, for 4 to 5 metres in height. At the other end of the chamber is a small water inlet high up, coming from a clogging that overhangs a terribly unstable absorption shaft. In the middle of the chamber is the « rocher qui a fait 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 being undetectable, one may think it is a fairly old fall and that the chamber has therefore not been reworked since. Beside this block, a shallow shaft but a real soap bar, as well as a squeeze at the top of a shaft near the entrance of the chamber, stop progress for lack of equipment.

In the end, it is a small cavity (85 metres of passage, for a depth of -23 metres), very endearing and surprising for certain dimensions (P18 and a chamber 17 metres long) that one would not expect to find in this sector of the causse.

A large broken stalagmite lies wedged across the shaft. The walls are well covered with concretion and many calcite crystals reflect the light of the lamps. The chimney of the small chamber is very well decorated with glistening flowstone and draperies; the floor bears brown calcite cauliflowers and a beautiful perfectly white flowstone 4 metres high.

From a hydrological point of view, the causse 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; both are 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 chamber where they disappear through the absorption shaft. One may 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 equipment well (rope and ladder, since the shaft was not rigged for jumaring) out of reach of stones, because it « parpine » hard on the way up or down of the team members.

Return shortly afterwards with the digging equipment: the attack with the chisel allows Marie-Thérèse Milhas to pass, but not her husband. Behind the crawl (whose crossing was heroic), Marie-Thérèse reaches the small chamber; the brown calcite cauliflowers will, alas, have to be partly sacrificed to continue. Marie-Thérèse being alone on the exploration, the very narrow tube marked the end of the day. Meanwhile, the Hilti was purring in the wall of the crawl at the foot of the shaft, and the charge soon set off pulverised the stubborn rock.

On the third visit (Milhas Marie-Thérèse and Claude, Rouby and Montaudié), a side passage in the main corridor was first explored, with access to a stretch of lower passage that is clogged. A start of digging at the bottom of the absorption shaft, in a very airy and shifting clogging, does not allow one to see any immediately penetrable continuation; given the danger of collapse, we abandon. 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 of the 2 shafts 4 metres deep, both opening onto the same « diaclase » (or rather a vertical passage between the blocks constituting the subsoil of the chamber). This passage ends in strictly impassable squeezes in the direction of the nearby absorption shaft.

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