A treasure of the North China gorges-the Yesanpo "One-Hundred-li structural erosion gorge": Its origin

The Yesanpo National Geopark is located at the north end of the Zijingguan fault, in Laishui County, Hebei Province. The "One-Hundred-li structural erosion gorge" (li is a Chinese unit of length (=1/2 km)) at Yesanpo is composed of three separated erosion gorges with a total length of 52.5 km. They are developed in cherty-banded dolostone of the Mesoproterozoic Wumishan Formation on the east side of the Zijingguan fault. There occur four Meso-Ceno gigantic vertical structural joints, which, especially the Himalayan N-S-trending tensional joints, are the prerequisite of the formation of the erosion gorges. The rapid crustal uplift in the Pleistocene and physical weathering and erosion, especially the erosional process of the flood in the mountains, are the direct causes for the formation of the gorges. The One-Hundred-li structural erosion gorge is a special karst geomorphologic feature.