dong Xiăochăngdà Dòng - 小厰大洞

Analyse :

3632 caractères - lu : 460 Fois
Located 1.3km southwest west from Shichao. The entrance is in a doline(75m major axis, 50m minor axis) and have 3 big branches. Doline's edge line is vertical wall(and it's not able to go down without rope) except south end. It's able to go down by walk from south end of the doline. There is a doline is river at the bottom that have no water in winter.

Xiaochangdà Dòng No.1
Opens in northeast-end of the entrance-doline. The entrance has artificial stone wall. Hall with a diameter of 20m is adjacent entrance. The hall has vertical pipe(30m depth) in ceiling. At the highest ramp in northeast of the hall, the passage extend deeper. Humidity and the temperature go up suddenly at this ramp. Because there is no air current, other entrances are not expected. There is another Hall(20X15m of width, have many speleothem) 50m far from entrance. At west end of this hall, it's possible to climb 15m then blocked.
According to the locals, there was a ladder and a passage continues. But we have not found any passage.

Xiaochangdà Dòng No.2
A penetrated under ground river. The outflow entrance is at west end of the entrance-doline. The inflow entrance is 200m northwest west from the outflow entrance, and water is gathered from two surrounding valleys. In January, no water in the cave. Water is into underground. Our local guide said swimming is necessary in rainy season.
At the inflow entrance(7m of width, 8m high), rocks are scattering. Gentle down slope continued 50m from the entrance, and ceiling is gradually lowering. In the narrowest point, ceiling height is 0.6m, and 2-3m of width. This narrow area will be filled water in rainy season. After the slope going up 2m, different form passage appears(13m of width, 10-20m of ceiling height).
There is 4m height waterfall and able to climb up. We could see Meander trench, but not explored. Curved stream goes down 30m on rock from the waterfall. There are some little pools. In this area, lower level of cave-wall shaped curved, but upper level of cave-wall shaped straight. After passing through the curved stream, the floor became flat and scattering stones, and connected to vertical entrance near the outflow entrance. The vertical entrance has 8m depth and opened along with cave-formation-direction. The cave changed the direction to east, after going 40m, reaches to the outflow entrance in the entrance-doline.
There is a hall(20X30 width) adjacent outflow entrance. It has a karst-window(connected to outside, but it's difficult to go up) in northwest on ceiling.
Passage entrance(3m width, 4m height) opened at the wall positioned 30m North-East from entrancedoline. Passage has 5m width, 15m length and extends to North~North-West. Passage's floor(inclined about 20 degrees to deeper) is covered with mud and gravel. Ceiling height got lower in deeper. It's not able to feel breeze.
Xiaochangdà Dòng No.3
The inflow entrance opened in the east end of the entrance-doline. The entrance has 40m height and 50m width, but inside of the cave is narrow. In dry season, water is coming form right side of the entrance and absorbed just there. There is two little entrances(1-3m height) in the big entrance area. And both of two little entrances connected to a hall inside. A stream is coming from right side of the entrance. The stream along the meander trench(1-2m of width, 1-3m height), continues 40m and going under water. A passage from other side of the entrance, extends 50m (5-8m width, 2-4m ceiling height) then meets outflow from
right side of wall, and goes under water. Location of the flowing suggests it come from the meander trench.(GOTO)