Discovery of an angular unconformity between the Middle Jurassic Bathonian Stage ang its underlying metamorphosed basement in the Chawola district, Nyainrong County, northern Tibet, and its geological significance

An angular unconformable contact was for the first time found between the Middle Jurassic Bathonian Stage and its underlying pre-Ordovician metamorphosed basement in the Chawola district, in Nyainrong County. In the Sog County-Zogang stratigraphic area, including the Chawola district, only the Bathonian Stage in the Middle Jurassic unconformably overlaps on the "shallow basement" metamorphic series. This reflects that "the central uplift" in the Qiangtang basin is developed not only area of Shuanghu but also in the east of Chawola district. This discovery has great significance for the tectonic-paleogeographic study in this stratigraphic area.