dong Bamboo cave - 竹洞

Détail


Nom de la grotte : Bamboo cave - 竹洞
Autres noms :
Province, Préfecture, District :
Chongqing 重庆, , Wulong 武隆县
Latitude Nord - Longitude Est :
29.25145 - 107.93769
Altitude (m) : 793
Développement (m) : 1 714
Profondeur (m) : 356
Profondeur - / + (m) : 0 /
Volume (m3) : 0
Géologie :

1Entrée : Bamboo cave 竹洞,

Carte



Description 1



Take road north from Tianxing to ? ? Cun. Follow muddy road to right. Just past the first farmhouse on right there is an obvious path down on the right. Descend 25m in elevation to a saddle. (To the left from the saddle leads to Cha Zi Ba.) Continue uphill. The shaft is to the left in a bamboo thicket.

Bamboo Cave entrance is sited on a fault running north/south. It is an active river cave, going from dry to 'wet sporting' with a couple of days steady rain. The trend of the main route changes several times which is not easily noticed in a twisting streamway - starting north, thne west, north again and finally south at the approximately 350m altitude.

The entrance is an impressive, wide shaft surrounded by a bamboo thicket on one side and a mixture of undergrowth on the other sides. A safety line from a tree at the northern end of the shaft provides a safe descent to a bigger tree which overhangs the shaft. The main hang is from this tree. Care is required as debris is easily dislodged.

The 40m daylight pitch lands on a detritus slope, very slippery and steep. The main hang needs to be long enough to reach all the way down this slope to the head of the next pitch, which is still within daylight but safe of any debris which may fall from the top (an 80m rope will suffice). A level surface provides a safe take off point for this next short rebelayed pitch (10m, 10m). Immediately is a 5m climb down - care: logs and general debris at the head. Trailing a longer rope from the last pitch (+10m) may be a wise precaution.

Progressing along steeply descending passage, another climb down (3m) is reached (large muddied nodules protrude from the walls), then a series of easy going cascade style descents to a sloping ledge of clean washed rock in large passage. A narrow gully cuts into the floor. The angle of bedding at this point is noticeably steep, continuing in this style throughout the cave. Ahead, a large wedged boulder marks the start of the next pitch (30m).

After descending the pitch, the stream runs off into steeply descending passage which begins to meander, becoming narrow enough in places to make progression more awkward. Within ten minutes a short climb down of 4m into a pool is followed almost immediately by a short 12m pitch in drippy conditions. Meandering canyon leads to the next pitch (30m, also drippy). The canyon continues beyond the drop as the narrowest section of the cave. Quickly, an 11m pitch is reached, followed by more canyon with two 4m climbs to stay with the stream. One is just prior to the head of the next pitch, a splendid 65m drop with several re-belays to avoid any water, in an ever widening shaft. This shaft has a window into a second, accessed by swinging onto a ledge from the last bolt. A short climb down on the other side of the ledge leads into unexplored canyon passage. Where the water goes or comes from is currently unknown.

At the bottom of the hang, following the water down steeply in tightish canyon soon opens out into easy walking streamway. Initially, the style is cascades with some pools to wade but eventually this changes to gravel floored passage. A significant inlet comes in from the right, shortly before an area where the passage looks like it may sump. Passing around to the left side, the route opens out again (be aware on return that this place is the only point where the way out is not obvious). Just prior to and at this location, the walls and ceiling are covered in fragile 'popcorn' formations which can be brushed off easily. This popcorn becomes rather common in the cave but not seen at the current active water level.

Two other inlets are passed, along with two boulder chokes (at floor level) before the passage ends at a flowstone constriction. Above the first boulder choke is a large chamber, the access to which is via a climb up from the streamway starting on the right hand side. The main way on though continues as a 5m crawl in the stream under the choke, opening out into walking passage again. Now less steep, the cave has changed character, as well as direction, to head south. Longer straight sections with flowstone and associated formations make this the best part of the cave trip. Rock structure is rather unique, consisting of a cemented breccia containing a high proportion of white calcite lumps. At one point, a flowstone slot above the streamway (drippy) is passed as an alternative to a crawl in the water. Just beyond this, a trench with a pure white calcite floor runs for 15m before a turn in the passage. The final choke is in flowstone covered blocks where a draught exists but no obvious way on was found.

BRJ, JFK, DJB 2004.11.04



Analyse :

4678 caractères - lu : 2 Fois


Bibliographie 2



http://www.hongmeigui.net/
http://www.hongmeigui.net/
Site sur les campagne d’expéditions du club de Hong Mei Gui. Dans les provinces du Guizhou, Guangxi, Yunnan. Explorations dans les comtés de Leye, Nandan, Guilin. Données chiffrées sur les cavités topo données topo et photo chronique d’expédition.
Source : Web

Aut. Var. edited by Erin Lynch
Hong Meigui Tian Xing 2004 Expedition. Cave expedition to Tian Xing, Chongqing Municipality, China 29th September to 5th December 2004 Final Report.

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Topographie 0




Expédition 1


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