TuotuoheJur Fm

It was named by Bai Hiasheng in 1989. The naming section is located at Yanshiping by the Qinghai-Tibet Highway in Qinghai Province, with its reference section being situated at 7 km southeast of the Quemoco of Tanggula Township, Germu (Golmud) City, Qinghai Province (Regional Survey Party of Qinghai Province, 1987). Schematic strat column in previous "red Chinese Lexicon" suggests it is the upper-lower formation in the Yanshiping Gr.

Synonym: （沱沱河组）; The Tuotuohe Formation is regarded as the synonym of the Buqu Fm, and this Tuotuohe Fm name has been assigned to a Paleocene lithostratigraphic unit in this same Golmund City region by Bureau of Geology and Mineral Resources of Qinghai Province (1997); therefore, the suffix-qualifier of "Jur" was added in this Lexicon to avoid overlap.

The formation represents alternating layers of grey-violet medium-, and thick-bedded sandstones in association with grey-green medium-, and thick-bedded quartz-siltstones, intercalated with grey and grey-white quartz-sandstones, calico-ferruginous siltstones, grey-black bio-limestones and marls, with a thickness of 1283 m at Yanshiping, and of 530 m in the Quemoco area.

In the middle and lower parts of the Yanshiping section the aspect of the contained bivalve fossils is similar to that from the Quemoco Formation, and of the Brachiopod fossils there occur such members of the Bajocian stage as Monsardithyris rauzevauxi, Sphenorhynchia matisconensis and etc., with the upper part of the section being rich in bivalves of the early Bathonian stage such as Isognomon (Mytiloperna) murchisoni, I. (M.) bathonica, Emiodon angulatus, Astarte oolitharum and Protocardia stricklandi, as well as Brachiopod fossils as represented by Burmirhynchia gutta and Holcothyria subovalis.

It represents normal shallow-sea deposits.