Perte d'Asin n°1

The sink passage is very low at the entrance, winding and cut by numerous gours. From 1.40 metres to 4 metres wide, its paragenetic ceiling, 0.80 to 2.50 metres high, forces a stumbling progress through mud and plant debris. It rises steeply at 125 metres from the entrance until reaching 2.50 metres in a comfortable passage. The zone of passages excavated along a bedding joint is very wide and low-ceilinged; the exit is through a very aesthetic passage 4 metres wide by 1.30 metres high. After the second sink, the passage, at first low and muddy, rises and widens very quickly to become very spacious: from 1.50 to 3 metres wide by 2 metres high; of paragenetic type, it remains winding.

The Bousquet stream sinks underground and joins to the south the waters of the Cazaux stream, itself a small tributary of the Gers. This underground circulation is described in an article by Dr Ch.CADEOT, published in 1959 in the bulletin of the Société Archéologique du Gers under the title: « L’érosion karstique dans le Nord du Lectourois ». We follow the stream for a distance of 16 metres at the bottom of the doline and it is lost again in the grey limestone of the Agenais through the very low porch of a second sink. The passage, however, gradually fills with water which quickly reaches the waist, then the chest.

The progression is particularly wet from the arrival in the zone of passages excavated along a bedding joint and all the way to the exit. A 3-metre-long duck leaves only 10 centimetres of space between the water surface and the ceiling. After the second sink, a duck a few metres long precedes the exit. This very fun through trip is particularly wet and it will be preferable to wear a neoprene suit so as not to suffer too much from the cold, because the immersion time is still fairly long.

The development of the whole of this underground route is 572 metres, which makes it one of the major caves of the department in terms of development, with in addition the particularity of offering one of the two integral sink/spring through trips along with the through trip of the HONTAMBERE cave (and if one does not count the pont du diable/œil du diable through trip which requires speleo-diving skills and equipment). The exit is very beautiful because the daylight filtered by the foliage of the vast doline 20 metres in diameter gives unreal tints to the walls of the passage.