Dashiwei Tiankeng Scenic Area
it is predominant by dashiwei tiankeng that this scenic area is composed of tiankengs of dashiwei,baidong, shenmu, datuo, luojia, sujia and yanzi, dashiwei underground river, and caves including zhongdong, zhuomudang, baidong and maoqidong, yanpeng coal mine remains, datuo and chanziyao faults relics, permian phylloid algae fossils, as well as cultural relic of baji village limekiln paper-making workshop and tiankeng forests.
dashiwei scenic area was opened on may 1st, 2003. it has not only good bus road but also good paved hiking way. bus tour has two ways: the eastern way is from jiangjia’ao gate to datuo tiankeng, baidong tiankeng, maoqidong, arriving in dashiwei eastern peak parking lot, and the western way from shuijing’ao gate to dashiwei western peak parking lot, arriving in the southern col parking lot, the eastern bus way and the western bus way are connected via chanziyao village. it lasts about 1.5 hrs.
the paved hiking way is from jiangjia’ao gate to baidong tiankeng parking lot, then walking through baidong tiankeng to shenmu tiankeng, maoqidong, yanzi tiankeng, sujia tiankeng, luojia tiankeng, getting to dashiwei tiankeng, and hiking around dashiwei, to shuijing’ao gate. it lasts about 3-4 hrs.there is specific tour bus in the scenic area and also public bus from the gates to leye county town.
dashiwei tiankeng is located about 2,000 meters south of baiyanjiao in shuaba village, tongle town, and 12 km from leye county town. the tiankeng formed in thick permian limestone; structurally it lies on the axis of an anticline, while geomorphologically it lies on the boundary between fengcong karst and a valley.
dashiwei tiankeng is 613m deep, with a volume of 75 million cubic meters, and an entrance measuring 600 × 400 m. the area of forest at the bottom is 105,000 square meters. zhongdong and mafengdong caves are located in the eastern peak of dashiwei tiankeng. these caves contain neogene sedimentary profiles. at the foot of the western cliff is the dashiwei underground river cave system, which has been explored for 5 km so far. rare cave animals such as pholcus, potamonidae and the translucent golden-line barbel sinocyclocheilus hyalinus have been discovered in dashiwei. some rare plants are found on the floor and cliffs and around dashiwei tiankeng. dashiwei tiankeng was opened to the public for viewing in 2003, but access to the floor of the tiankeng is forbidden.
baidong tiankeng is named for the white cliff on its north side. it is situated 2.4 km east of dashiwei tiankeng and only 300m in distance from shenmu tiankeng, separated from each only by a hill. it is accessible on the northwestern side of tiankeng, while at the foot of the south cliff there is a cave entrance which connects with yangguang chamber in maoqidong cave 400m away. at the bottom of baidong tiankeng there is dense forest, including ornamental square bamboo.
baidong tiankeng has an almost circular entrance surrounded by cliffs. the eastern col is the lowest point on the rim at 1207m asl, while the highest point is the eastern peak at 1321m asl; the height difference is 114 m. the tiankeng entrance is 220m long and 160m wide with an area of 21,960 square meters; its maximum depth is 312m and the average depth is 263 m. the lowest point at the base is at 1010m asl. the volume of the tiankeng is about 5,786,000 cubic meters.
baidong tiankeng, baidong cave and maoqidong cave together with baidong underground river form a vivid model of tiankeng evolution, which is valuable for scientific research, outreach, exploration and sightseeing.
shenmu tiankeng formed among depressions and peaks. it has partially collapsed, forming two triangular cliffs on its west and north sides. the tiankeng has an irregularly shaped entrance 370m long and 340m wide with a depth of 234m and a volume of 13 million cubic meters. there are accumulations of collapsed rock at the bottom, which indicates that the early underground river failed to promptly move collapsed rocks when the tiankeng formed.
at the bottom of the tiankeng there is dense forest consisting of 400 plant species, it including some rare plants such as taxus chinensis, dendropanax chevalieri, photinia serrnlata, pinus kwangtungensis, orchidaceae calanthe, horse chestnut and neottopteris nidus. the tiankeng floor is accessible via the southern col.
maoqidong and baidong tiankeng, which lies only 400m away, both resulted from the collapse and exposure to the surface of baidong underground river passage. maoqidong is shaped like an inverted funnel with a skylight in the ceiling 410m high; the chamber below is called yangguang chamber, or the funnel of light. the chamber is 180m in diameter, about 27,600 square meters in floor area and about 5.2 million cubic meters in volume. at the bottom is a huge mound of collapsed rock, which slopes down to an underground river passage. maoqidong is in fact a karst window into baidong underground river cave.
maoqidong is a large shaft into a huge cave chambe; a 260m high beam of sunlight shines into the 180m-diameter yangguang chamber. maoqidong frequently exhibits a phenomenon whereby the difference of humidity and temperature outside and inside the cave chamber produced a breathing effect, with air being forced out of or drawn into the skylight. maoqidong is not only a paradise for cavers’ adventures but also makes a natural classroom for visitors to understand tiankeng development.
the tiankeng, skylight chamber, rock pile, underground river and breathing effect give tourists a vivid understanding of how tiankengs evolve, what karstification is and the excitement of cave exploration.
dengjiatuo tiankeng is the third largest in the tiankeng group. it is surrounded by curved ridges of fengcong, and looks like a shield in plan. it is 470m long in the north-south direction and 370m wide in the east-west direction, with an area of 128,200 square meters, a maximum depth of 278m and an average depth of 222m. the floor area of the tiankeng is 107,800 square meters and its volume is 26.19 million cubic meters.
it has cliffs more than 150m high on the north, southwest and east sides, in which many honeycomb-shaped caves are seen, and has a flat area of 5,500 square meters at the bottom, which is second only to that of huangjing tiankeng, and accessible via a small path.
datuo tiankeng is the second largest tiankeng in the tiankeng group. it is surrounded by 4 peaks with altitudes of 1290~1335 m. it has an entrance 534 ×380m in diameter, a maximum depth of 290m and an average depth of 263m. the area of the entrance is 148,800 square meters and the volume of the tiankeng is 32.4 million cubic meters. it is accessible from the south side.
sujia tiankeng is located 550m north of wachang village and one kilometer east of dashiwei tiankeng; it is oval shaped and surrounded by cliffs formed from three peaks separated by three cols. from east to west it measures 244 m, and 134m from north to south. it is 167m deep and has a volume of 26.3 million cubic meters. there is a dense forest at the bottom containing rare plants such as leafy paris.
yanzi tiankeng is named for the swallows (yanzi) nesting inside. it is 100m long and 60m wide, with an entrance area of only 5,450 square meters, however its floor area is 14,340 square meters as the tiankeng is bell shaped. its volume is 1.69 million cubic meters. the tiankeng walls are cliffs more than 100m high all around, but several pits for nitrate extraction were built at the bottom many years ago. it is still unknown how people accessed the tiankeng to build these pits. the bottom of the tiankeng is full of dense vegetation, mainly ferns