Lvcun Gr

The type section is located at Luecun, west bank of Yarlung Zangbo River, South Nieru District, Kangmanieru District, Tibet Autonomous Region. It was named by the District Survey Team of the Tibet Autonomous Region Geology and Mineral Bureau in 1984. And it was first cited by Rao Rongbiao and others in 1987.

Synonym: Luecun Gr, Lucun Gr [the Lvcun spelling seems most common]. In 1974, Yin Jixiang and others referred to the Triassic system in the northern area of Mount Everest (Qomolangma) as the Jilong Gr. In 1984, Wu Haoruo thought that in the northern area of Mount Everest, there are significant differences between Triassic in the southern and northern parts, so he named a set of Triassic silty and calcareous slate intercalated with quartz sandstone and marl generally containing pyrite strata on the Permian Baidingpu Fm between the southern Kangma and Gyangze as the Zhuoga Gr. In 1984, the Tibet Regional Geological Survey Brigade divided the regional metamorphic strata in Kangma, Sakya, and Tingri into a lower Lvcun Gr and an upper Niru Gr (Nieru Gr).

It is mainly composed of black slate and dark gray phyllite with dark color and very single lithology, rich in pyrite spots or crystal grains and chlorite, and locally metamorphic into schist. The thickness is 600 to 800 m.

Only few bad-preserved ammonoids and some bivalves were found in the upper part, such as bivalves of Halobia cf. rugosoides, Daonella cf. guizhouensis.

Marine facies