Woduhe Fm

The name was proposed by Ma Jiajun et al in 1963 and published in Regional Stratigraphical Scale, Heilongjiang Province in 1979. The type section is located on the right bank of Woduhe River, approximately 25 km north of Duobaoshan in Lenjiang County, Heilongjiang Province. The reestablished representative section is on the southern bank in the lower reaches of Xigulanhe River, about 10 km northwest of the 727 Forestry Farm in Aihui County. The reference section is on the western bank in the lower reaches of Dahelihe River in Aihui County, approximately 25 km east of Duobaoshan in Lenjiang County.

Synonym: (卧都河组) . In the area of Diyingzi-Yinogaigou, where it used to be called the Huanghuagou Fm, the Yinogaigou Fm, the Wuka Fm and the Woduhe Fm, yielding Tuvaella gigantea, containing abundant tuffaceous components and disconformably resting on the Ergunhe Gr (Zn-C1) (577 m in thickness); used to be called the Suhuhe Fm (930 m thick) at Yirxie, Arxan, Horqin Youyi Qianqi of Inner Mongolia; used to be named the Bayundele Fm (>2345 m in thickness) in Dong Ujimqin Qi (Banner), Inner Mongolia.

The formation, 382 m in thickness, is dominated by clastic rock. Lower part of the formation consists of gray green siltstone intercalated with medium- to coarse-grained quartzose sandstone, partly facies-changed into purple calcareous slate with calcareous siltstone partings, or with minor volcanic rock and tuff. Upper part is composed of medium- to coarse-grained arkosic quartzose sandstone intercalated with siltstone and pebbly sandstone.

The Tuvaella rackovskii- T. gigantean (Trg) assemblage is the representative fossil in the lower part and, in addition, there is also the Janius exsul assemblage found in the purple calcareous shale. The Tuvaella gigantean (Tg) assemblage is the representative one in the upper part of the formation.