Aven Acheron

The cleared entrance reveals the 11-metre entrance shaft (draught). Once descended, a cleared opening in a fill gives a flat-out passage (crawl), also cleared, that leads into the Puits de la Pierre (P11). At its base, three possibilities for continuation.

Possibility 1: a P8 ending on a boulder choke.

Possibility 2: another P8 joining the first. The cavity continues through a 20 m shaft (Puits Turc: 6 and 14 m) ending on a debris cone. After emptying it, a cleared pinch at -54 gives access to a 42-metre shaft (Burn Out). The cavity then continues through a slightly widened and cleared fault (l'Ecaille). A passage under blocks (to be negotiated with caution) gives access to a 15-metre shaft (Puits de la Vipère).

Possibility 3: descent of a 26-metre shaft followed by an 11-metre shaft. Ends on a chaos at -69. The cavity continues through an 11 m shaft and a 12 m shaft. There, one reaches the Puits de la Vipère. At the base of this shaft, an uninviting debris cone gives a fine 26-metre shaft (Puits Damoclès): this shaft offers several possibilities for descent, one of which allows one not to descend beneath the debris cone. An 11-metre shaft then develops and ends in a chamber of fine dimensions (initial floor at -150). Halfway down the shaft, on a step, the continuation was found: Un petit trou (a small hole) 0.2 metre in diameter.

Its clearing yielded 2 possibilities. Possibility A: a horizontal passage (handline) leads to a window and a 4-metre step; a) descent of 2 shafts (7 and 10 m) to reach a chamber on a chaos (lowest point of the cavity at -165); b) access to a chamber where several continuations are present. At the bottom, a P14 develops (Puits Désespoirs). At its base, a meander allows one to return to the starting chamber. Above the P14, a climb of about 40 metres, from ledge to ledge and often from debris cone to debris cone, allowed one to drop back into the main fault.

Possibility B: descent of a 5-metre shaft and a very low passage under a stratum. A chamber of very fine dimensions then develops, with 2 small chaoses connected by a stream of gravel. Note the presence of Un petit départ (a small departure) at the bottom of the chamber[ref]Guillaume CHARDIN - CDS83, Fichier des cavités du Var > "Aven Acheron" (numéro 2127380): http://www.fichiertopo.fr/display.php?details=1&indexid=97[/ref].

Potential junction with the Grand aven de l'Étrier

In January 1999, with an outside wind, the aven Acheron was blowing while the Grand aven de l'Étrier was drawing in. The entrance of the aven Acheron is located 10 metres lower (altitude) than the entrance of the Grand aven de l'Étrier[ref]GrottoCenter > "Grand aven de l’Étrier" (numéro 5815): http://www.grottocenter.org/html/file_Fr.php?lang=Fr&check_lang_auto=false&category=entry&id=5815[/ref]. Considering the respective depths (-165 and -152), the bottom of the aven Acheron is 23 metres lower than the bottom of the Grand aven de l'Étrier[ref]Guillaume CHARDIN - CDS83, Fichier des cavités du Var > "Aven Acheron" (numéro 2127380): http://www.fichiertopo.fr/display.php?details=1&indexid=97[/ref].