Grottes et karsts de Chine
Sur les traces de Xu Xiake

Bien Fu Dong No2 (Bat cave)

The cave is located 2.6 m far form the Zhangmingshan Village( Hemu vill ) on the right side of the Monle River. The entrance is situated ~ 60 m higher from the river in a cliff located on the N slope of the river valley. Altitude - 1296 m altitude.

WGS Coordinates: N24.98442 E98.80489

The cave is a spring. It is a typical karst phenomenon, formed through the system of brittle fractures that inherited the ductile fault. It is a single meander developed along the fissure with direction S-N. It is formed in marbleized limestone, immediately below their contact with black mudstones. The contact itself is tectonic - a ductile thrust fault developed in the conditions of greenschist facies. The limestone and the mudstones are strongly mylonitized. In the first couple of meters below the contact, the limestones contain many lenses and levels from the mudstones. The mylonitic foliation from the two sides of the contact is sub parallel to the stratification. It slips down to East with mainly 50° dip. The mineral lineation climbs to NE.

The entrance has half episodic form with dimensions 5.60 m wide and 5 high. The first part is dry. The right side of the entrance is formed as a bed of the river which comes out from the cave. Discharge ~ 1-2 l/sec. Strait away after the river covers all surface of the gallery. The passage ended with a like formed by the water which springs from the underwater fissure located on the foot of the wall. In the left (W) side of the gallery there is a threshold (step) of + 3-3.5 m which lead to the upper and dry level of the cave. The passage keeps its character about 30 m. In this place the river, coming from inside hides in a narrow appendix in left. The gallery continued upstream around 40 m. Ahead, from where the water comes, it become narrow and not passable. The cave continued in upper level reachable after short free climbing (+ 4 m). Here the air temperature of become higher ( ). The next 110 m are relatively more confined (1.2 m wide; 1.5 m high). Further there is 10 m of narrow, after which the cave becomes wider and higher. After 100 m the gallery turned. Then the cave becomes low, narrow and branched. The right branch is scandent and its end marked the highest point of the cave +32 m. The total lenght of the cave is 429 m, and the Depth: + 32 m. The cave is surveyed at 29 October 2011.