At Wumao in the Yuanmou Basin, an earth forest rises from deposits cut by erosion. A field-course report from Yunnan Normal University’s Department of Geography describes the local Quaternary river-and-lake sediments as the Xigeda Formation and records students examining their lithology and joints.
The field account describes seasonal concentrated rain acting on the hot, dry valley through sheet erosion, gully erosion and collapse. These processes cut the sediment into gullies and upright columns, leaving the layers legible in the landform.
