Wu Jiang

Geomorphology And Cave Development

China Caves Project

CAVES OF THE JIANG KOU AREA

Kev Senior

The landscape around Jiang Kou is dominated by two major rivers: the Wu Jiang and the Furong Jiang. A major fault runs north-south just west of Jiang Kou and the Wu Jiang follows this for part of its course. Approximately 500m of permo-Triassic limestones are thrown down to the west of this fault, which is responsible for the 1250m-high escarpment above the west bank of the Wu Jiang. The Wu Jiang turns northwest at Jiang Kou, cutting a gorge through the dip of the Triassic limestones.

To the east of the fault the Triassic limestones rest unconformably on Palaeozoic formations and form an outlier in the hills north of Jiang Kou. The Palaeozoic formations consist of Silurian and Ordovician shales, but beneath these are lower Ordovician and Cambrian limestones. The Triassic cover has been eroded from the karst plateau above the Furong Dong show cave and all the caves shown on the map of are developed within Cambrian limestones.

Expedition explorations concentrated on the Cambrian plateau and only a few visits were made to the Triassic limestones.

In summary, the structure of the Cambrian limestones consists of folds with north-south axes, associated reverse faults, and major joints trending east-west. This means that here, as in the Xin Long area, water must flow across the geological structures to reach base level in the Furong Jiang. Consequently joints that cut through the folds provide very important guidance to cave development.

Furong Jiang joins Wu Jiang at Jiang Kou

The new extension discovered by the 1994 expedition in Furong Dong provides a window into the active phreas 1200m below. The big chamber at the end of the extension is defined by two prominent faults, one of which strikes about 050 degrees and dips to the northwest and a second that is vertical and strikes east-west. The east-west fault almost certainly takes the water towards a resurgence near English Speaker's Cave. There is no obvious resurgence In the Furong Jiang, but while rafting down the Furong Jiang, an abrupt reduction in the water temperature was noticed below Furong Dong. English Speaker's Cave is known to be an important resurgence in very wet weather, so it is presumed that the deeper phreatic system resurges beneath the surface of the Furong Jiang, somewhere near to English Speaker's Cave.

Furong Jiang

Several streams sink in the valley that runs from Tian Xingtowards Furong Dong, but Zhan Ren Ken Dong, Dong Ba and Xin Lu Kou are all developed down dip, perched above thin shale beds. All three caves trend northeast, away form Furong Dong. There are many unexplored shafts on the plateau. Of those visited, the unexplored shaft number 4 is in a particularly promising position to drop into the passages presumed to exist east of the terminal choke in the Furong Dong show cave.

Jiang Kou Area Map

Yangtze 94 Index

Explore