Printed from: on 19 Nov 2017
Copyright: © 2017 - 2017 John Gardner

Réseau de la Dent de Crolles, Chartreuse

Réseau de la Dent de Crolles, Chartreuse
Photograph of the main passage in the lower story of Trou du Glaz
Note the dip of the strata running down from right to left
Photograph: Dave Checkley


The Dent de Crolles is part of an extensive Early Cretaceous limestone massif in the Chartreuse hills of the French prealps. It has a summit of 2062 metres that towers over the Isère valley to the south, whilst to the north a tilted synclinal valley, protected by high cliffs on the west and east, descends from the summit for 1½ km to the edge of a cliff-encircled cirque that plunges into the Perquelin valley.

The massif is honeycombed by a cave system with over 60 km of passages contained within an area of under 2 km². The Réseau de la Dent de Crolles, as it is known, has eleven entrances that include the resurgence (Grotte du Guiers Mort, 1332 m), and a top entrance which is located just 175 m from the summit (Gouffre Bob Vouay, 2026 m). It is made up of a number of active systems that drain into a master cave, and a number of far older large fossil phreatic systems. The latter were probably formed during the mid-Pliocene, and drained a landscape long since disappeared. They were truncated during the Quaternary glaciations, and now have large entrances overlooking deep valleys on the east, west, and north sides of the massif. The fossil passages have been intercepted by the active systems to create a vast interconnected network the plan survey of which has been likened to a plate of spaghetti.

Dent de Crolles plateau and summit from the south
Dent de Crolles plateau and summit from the south - the Perquelin valley is in the foreground
The highest entrance is near the col left of top centre, and the resurgence is bottom right of centre
Click image for larger resolution

The Réseau de la Dent de Crolles provides perfect holiday caving, with a large number of classic through trips and round trips possible of varying degrees of difficulty, as well as providing scope for more challenging expedition-style caving. It is possible to traverse from the top of the mountain to near its base, and through the mountain from west to east, and combinations of the two. Several of the more popular routes have been superbly equipped with pull-through chains and traverse lines, and are waymarked. Some of the through-trips take around 4 hours, and others over 12 hours. All the entrances are reasonably accessible with the walk-ins varying between about ¾ of an hour, and two hours.

The purpose of this website is to pull together the latest pertinent information on the cave, and to clarify the locations of the entrances. Please look at the Sources of information page for a summary of available material, much of it on the web.

As of 2017 the following 11 entrances are known. Those with links are discussed further on this site. The locations can seen displayed on the IGN Géoportail aerial photography website, based on work by Gilbert Bohec.

Name Northing Easting Altitude Linked Notes
Gouffre Bob Vouay 3 45.30960° 5.85445° 2,026 m 2009 175 m from the summit
Links with Trou du Glaz and Grotte Chevalier
Gouffre des Quanta 4 45.31679° 5.86455° 1,937 m 2001 About 160 m south of Gouffre Thérèse
Links with Guiers Mort
Accessed by a 50 m abseil down the eastern cliffs!
P40 1 45.31259° 5.85357° 1,930 m 1947 Equipped route to Trou du Glaz
Gouffre Thérèse 1 45.31821° 5.86458° 1,925 m 1975 Equipped route to Grotte du Guiers Mort
Gouffre de la Pulpite Irréversible 3 45.31407° 5.85586° 1,901 m 2010 Equipped route to Trou du Glaz.
Also links with Grotte du Guiers Mort
Puits des Cartusiens 2 45.32081° 5.86179° 1,780 m 2007 Links with Grotte du Guiers Mort
Grotte des Montagnards 5 45.309° 5.858° 1,765 m 1996 Entered and linked with Grotte Chevalier in 1966
Accessed by an 80 m hard rock climb on the eastern face
Trou du Glaz 2 45.31736° 5.85146° 1,697 m ---- Equipped routes to Guiers Mort, Annette and Chevalier
Exit for equipped routes from P40 and Gouffre Pulpite
Equipped round trip
Link with Gouffre Bob Vouay
Grotte Annette Bouchacourt 4 45.30599° 5.85375° 1,685 m 1946 Exit for equipped route from Trou du Glaz
Grotte Chevalier 4 45.30669° 5.85468° 1,670 m 1984 Exit for equipped route from Trou du Glaz
Links with Bob Vouay and Grotte des Montagnards
Grotte du Guiers Mort 4 45.32611° 5.85757° 1,332 m 1941 Exit for equipped routes from Trou du Glaz and Thérèse
Also links with Gouffres Quanta, Cartusiens, and Pulpite
Two equipped round trips
1  Location from Spéléo Secours Isère route guide
2  Location from Gilbert Bohec's survey
3  Location from author's GPS reading
4  Location supplied by Gilbert Bohec
5  Location estimated from Gilbert Bohec's survey

The following files are available for importing entrance location details:

  1. Reseau de la Dent de Crolles.gpx - for importing into GPS and Memory-Map etc.
  2. Reseau de la Dent de Crolles.kmz - for importing into Google Earth.

In addition to the caving, the area also offers magnificent walking, as well as ample opportunities for big route climbing, sport climbing, canyoning, and via ferratas. For more information on the area consult the author's Chartreuse website.

Dent de Crolles from the west showing 7 of the 11 entrances
Dent de Crolles from the north-west showing seven entrances. The other four are in the eastern cliffs
Click image for larger resolution


I would like to thank Gilbert Bohec, Dagobert L'Ecluse, and Glenn Jones for their generous help and advice given during the development of this website, and to the various authors and organisations who have generously shared the results of their endeavours with others via the web.