dong Wanrendong - 万人洞


Nom de la grotte : Wanrendong - 万人洞
Autres noms : Thousand People Cave,Resurgence
Province, Préfecture, District :
Hunan 湖南省, Dayong , Sangzhi 桑植县
Latitude Nord - Longitude Est :
29.67876 - 110.69733
Altitude (m) : 786
Développement (m) : 4 016
Profondeur (m) : 188
Profondeur - / + (m) : 0 /
Volume (m3) : 0
Géologie :

3Entrée : Wanrendong 万人洞, Double Arch , Aquaduct ,


Description 1

From Baiyan Tou follow the aquaduct upstream towards the obvious large entrance.

Imposing entrance with two resurgences flowing out of it.The Snake Skin B survey starts at station 57 on the Snail Trail. The passage begins as a vadose canyon roughly 2m wide, 10m tall with a few areas that are a bit wider. The passage has a modelled ceiling with a varying light and dark gray pattern. Heading upstream the passage remains generally the same dimensions. After about 70m into there are two small side passages to the right: a small crawl that opens into a narrow walking canyon, and a short climb up that appears to parallel the main passage.Beyond, the passage has a trickle of water. Upstream past a large nitrate pit comes to a boulder pile where the passage splits at B15 junction with water continuing in both branches. To the left is 2-3m wide, 15m tall canyon which goes 70m and ends in breakdown, while to the right continues to the northeast, roughly the same size a before but with a few small climbs up breakdown.Continuing along the right hand branch, at B17 the main passage makes a u-turn while straight ahead a small lead continues following the general trend of the main passage. Through a constriction it opens to 1.5m high by 2m wide passage that loops and turns almost due north. The passage pinches out in an area with a false floor.In the main passage, at b21 to the right is a small loop and to the left is a crawlway that begins to pinch out but could be dug. 10m further upstream a high lead to the left is a 7m climb that needs bolts. Shortly after, the passage quickly gets smaller, splitting with the lower passage choked with breakdown. The upper passage, to the right, also begins to pinch out but continues as a body sized belly crawl.From the doline entrance, a slope down on the right of the main passage leads to the Mi Shui streamway. Downstream 24m of stooping height passage is followed by a short crawl that ends in a sump pool. Upstream is a 3m waterfall. A climb up to the right will gain the elevation of the waterfall

but some form of traverse line will need to installed for the survey to continue. The walls upstream of the waterfall are smooth and sharply sloped for approximately 20m.Above the Mi Shui streamway there is a short crawl that continues.On the path to the main doline entrance a resurgence feeds an aquaduct and water cistern. From a 2m high entrance, passage heads west, enlarging after 10m to 12m wide, where a second small entrance comes in on the left and a nitrate pit can be seen. Here the stream runs down the right

hand side, with a wide slope of dry mud on the left and many cave crickets. After 60m the passage ends in a low sump, presumably the downstream continuation of Mi Shui streamwayThe survey continues trending north from the fork at the end of the previous survey. The left passage runs due north through large boulders with an undertermined ceiling and up a slope passing by multiple nitrate pits. After 120 meters the ceiling begins to drop 10 meters. A lower passage opens and closes for 70 meters to a large boulder. 40 meters after, a stream is met; downstream has not been pushed, while upstream meanders beneath the main passage, where a lead to the right twists and turns with a ceiling 1 to 4 meters for 40 meters passing a short side passage on the right before reaching a second stream. Wu Ren Gui reports that the downstream requires getting wet. Upstream, the stream passage continues for 50 meters when the ceiling opens to 15 meters and the passage moves to an upper level. After 60 meters of straddling the lower level, the ceiling drops to 2 to 3 meters. After 60 meters the passage ends at a formation choke with the stream coming out of the bottom.Continuing along the main passage, after 20 metres a fork is met; to the right is Cancer Zone. Following the left hand branch upstream 90 meters passing a sizeable pile of boulders, the passage averages 3 to 5 meters wide and 7 to 10 meters high and leaves and rejoins the stream at various points. At this point there is a lead to the left has not been pushed. 100 meters further upstrem, a large flowstone is met with a central column. Leaving the stream around the column to the left, the passage continues 30 meters up the flow and ends at the ceiling with a gurgling sound heard beyond. Travelling back upstream from the flow, the stream weaves 100 meters to a large pile of breakdown. The stream enters from the left and there is a hole at the top of the pile.At the start of Snail Trail, a climb up to the left leads into a twenty metre wide passage. Immediately there is a junction; to the left is a steep slope up at the top of which a clamber up through boulders reaches an upper level where to the left there is a 10m deep pit, while to the right a crawl through breakdown reaches a 20m long, low wide chamber where it is possible to crawl through boulders to the bottom of the 10m deep pit.Back in the main passage at the base of the slope, twenty metre wide, well-decorated passage is followed for 150m to a 2.5m climb up a bank of mud and cobbles, at the top of which a crawl leads to a tight squeeze, beyond which there are mud cliffs down and back up resembling that already passed.120m of 4-5m wide walking passage with a floor trench ends in a junction. Water enters from the right, which goes 100m through small passage to an aven beyond which the passage continues small (Wu Ren Gui reports it eventually gets bigger). To the left passes stals and immediately meets another stream 8m below. Downstream has not been pushed. Upstream goes up a slope for 30m to a small chamber. Straight ahead a short climb gains 0.5m wide rift (unpushed). Left from the small chamber goes 20m to a climb up above which the passage becomes narrower (1m wide) and enters a heavily decorated area with stal, straws, and helictites which make non-musical progress difficult. After 20m the formation density decreases and a the passage makes a sharp left hand turn. 30m later it enlarges at a well decorated corner. 50m beyond reaches a juction. To the right the water comes down a 3m climb which is tight. To the left descends a short slope to a 15-20m pitch to a wide passage with a small stream (needs 3 bolts). 11m wide canyon passage ends in a junction. To the right a tall and narrow canyon with clay covered walls may continue, but progress is made difficult by nodules of friable rock which break easily while climbing. To the left a formation room is followed by 1-2m wide stream canyon. The passage climbs 15m in waterfall stairsteps with a steep gradient, then 150m of 7m wide passage with large boulders, ends in an overhanging flowstone climb up to continuing passage (unclimbed).Heading downstream, the stream flows through two 20m tall natural bridges, known locally as Zisheng Qiao, The arches are followed by gravel floored easy-walking, smooth walled stream passage which after 150m cuts down steeply, ending at the waterfall seen from Wan Ren Dong's doline entrance.1884016EML DRJC 2005.03.03786788772
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