Qulonggongba Fm

Gu Qingge was named in 1965. The named section is located about 2 km from Nanlongjiang Township, Dingri County, Tibet. In 1965, Gu Qingge named the late Triassic Norian strata with a total thickness of about 1042 m in the southern part of Tingri, Tibet, mainly black-gray shale and sandstone, with a small amount of limestone lenses, as the Qulonggongba Gr. In 1974, Yin Jixiang et al. revised the scope of use of the Qulong Gongba Fm and restricted its time limit to the Early and Middle Norian stage of the Late Triassic. In 1974, Yin Jixiang et al. separated the 150 m quartz sandstone at the top of the original Qulong Gongba Fm as the Derirong Fm. The remaining sandy shale was the use range of the modified Qulong Gongba Fm.

Synonym: Qulong Gongba Fm

It is mainly interbedded with sandy shale and coarse sandstone, with a small amount of fine sandstone, bioclasts and sandy limestone rock or lens in the middle and lower part. Generally, there is little phosphorus nodules in the layers, which can be divided into four members from bottom to top. First member is dark green shale with thin bioclastic limestone. Second member is grey shale with thin quartz siltstone. Third member is dark gray mudstone and tan tabular quartz sandstone. Fourth member is thin to medium gray feldspar quartz fine sandstone interbedded with carbonaceous shale.

The strata can be divided into three Ammonoid zones from bottom to top: (1) Indojuvaries angulatus zone, (2) Cyrtopleurites soceus zone, (3) Pinococeras metternichi zone; into two Conodont zones: (1) Epigondolella abneptis zone, (2) Epigondolella multidentate zone; and a Bivalve fossil zone: Indopecten-Burmesia zone. The group also produces abundant brachiopods, ammonoids, hornstone, foraminifera, ostracods, sporopalyns, and the famous ichthyosaur Himalayasaurus tibetensis.

It is interpreted as sedimentary process from deep water to shallow flat shelf to coastal marsh.