Chapter 4: KARST AND CAVES OF WUXI COUNTY (SICHUAN)

Résumé -Abstract - Zusammenfassung -: The Wuxi mountainous area is located at the far east of Sichuan province, on the left bank of The Yangtse. It lies in the Daba Shan, which culminates at Dashennongjia (3053 m), in the western Hubei. Karstic morphology, with stepped cones and serrated ridges, is controlled by a strong E-W folding, with imbrications and inverse faults. The great depth of the valleys and canyons is linked with the very low altitude of the base level (100 m for the Yangtse). The Daninghe, downstream of Wuxi, flows through gorges at the foot of 1000 to 1500 m high walls of Permo-Triassic limestones. The climate type is mountain subtropical, controlled by monsoons, with a continental tendency: important amplitude of the temperatures (1 to 5) and precipitation  (1 to 15). P = 1255 mm/year and T= 16.4°C in Wuxi (210 m a.s.l.).
On account of the large relief, the hydrologic karst potential can exceed 1600 m, such as in the Eastern syncline of Wuxi where a river was reached  at -150 m near Tongchengba village. In the eastern part of Daguan Shan, it could exceed 2000 m. These potentials are the most important ones of Southern and Central China. Thirteen caves were explored within a distance of 30 to 40 km around Wuxi, at altitudes between 290 to 1080 m a.s.l. The two most important are Sifangdong (-158 m) in the east syncline  of Wuxi and Xinlongdong (-167 m, 1.6 km) which lies 40 km, west of Wuxi. Most of the springs are situated at the bottom or in the walls of the canyons (waterfall travertine).

Keywords: cone-karst, polje, shaft, hydrologic karst potential, canyon, folded structure, syncline, Silurian, Permian, Trias, Daguan Shan, Wuxi, Sichuan, Daninghe, Yangtse.