Chapter 7: Lichuan and Yichang counties (Hubei)

Résumé -Abstract - Zusammenfassung -: Two extensive visits were made in Hubei. In Lichuan county, a polje of the same name, located in the south-west of the province, is 25 km wide and 30 km long. It is drained by the Qingjiang, a Yangste affluent, whose sinkhole formed the Tenglongdong tunnel-cave, which is the longest in China and was explored in 1988 by a Chinese and Belgian team. The type of the karst, in Permo-Trias limestones, is fenglin and qiufeng-ouvala. Two caves were surveyed: Tanxiangdong (0.7 km) and Changmangdong (0.2 km). The red Yichang basin is located at the exit of the "Three Gorges" of the Yangtse; it is filled with red Cretaceous-Eocene sediments (conglomerates, sandstones, silts) accumulated during the Yanshan Cretaceous orogenesis. Right in the NW, we were able to have a look at the contact of the karst surface with the Cambrian dolomites and the Cretaceous conglomerates trapped in caves and basins. The small perched Jinshidong cave, 221 m long, is located in  a karst with dry valleys and ouvalas formed in the Cambrian.

Keywords: Tunnel-cave, polje, fenglin, qiufeng-ouvala, Permian, Trias, Cambrian, Sinian, limestone, dolomite, red formations, Lichuan, Yichang, Yangtse, Hubei.