Ancient Geological Relics of Yunxian Basin

Ancient Geological Relics of Yunxian Basin

Ancient Geological Relics of Yunxian Basin

The historic county of Yunxian is divided in two by the Han River. North of the river lies the southern foothills of the eastern section of the Qinling Mountain Range, while south of the river, it belongs to the Daba Mountain System, the same as the Wudang Mountains, which are 60 kilometers away.

Geologically, the Yunxian Basin falls within the Qinling latitudinal tectonic system. The Yanshan Movement in this region gave rise to the famous near east-west trending Liangyuan Fault Zone, also known as the Han River Fault Zone. It also formed several downwarped basins, within which the Tertiary red rock formations are widely deposited. In terms of topography, the overall terrain is high in the west and low in the east, with uplifts in the south and north, and the Han River valley in the middle. The Han River, the largest river in the region, flows eastward from Shaanxi Province through the gap between the Qinling and Daba Mountains, cutting through a series of basins and creating a landscape of alternating canyons and basins. The Yunxian Basin is one of the larger basins in the area.

Archaeological discoveries have revealed an ancient shell fossil belt approximately 500 meters long and 5 meters wide on the third-level slope land of Liaowadianzi in Liubei Town, Yunxian. The presence of both downwarped basins and shell fossils proves that Yunxian was once a vast ocean during the early Cretaceous period.