Dongxiang Fm
Type Locality and Naming
Linzia Basin. Xie (1991) named Dongxiang Bed for the 3rd Member of the original Linxia Fm. Li et al. (1995) divided the 3rd Member into the upper part Dongxiang Fm and the lower part Shangzhuang Fm. The type section of Xie (1991) is at Jiaozigou of the Dongxiang County, and the section of Li et al. (1995) is near the Dongxiang County.
Lithology and Thickness
The Dongxiang Fm is divided into two members at the type section of Li et al. (1995). Lower Member is a ~24 m sequence of, from bottom to top, bluish strongly carbonate-cemented fine conglomerates (gravels: subangular and 0.2-0.5 cm diameter), interbedded brownish red siltstones and mudstones with some sand -gravel mudstones at the bottom, yellowish brown silty mudstones intercalated with siltstones and mudstones, bluish grey strongly carbonate-cemented sandstones, and yellowish brown strongly carbonate-cemented siltstones. Upper Member is ~60 m purple mudstones intercalated with a number of particularly bluish grey or greyish white marlite beds 0.5-1 m thick.
Relationships and Distribution
Lower contact
In the type section, the Dongxiang Fm is in conformable contact to the underlying Shangzhuang Fm.
Upper contact
In the type section, the Dongxiang Fm is in conformable contact to the overlying Hujialiang Fm.
Regional extent
The Dongxiang Fm has a widespread distribution from the Daxia River drainage to the Guangtong River drainage, but the marls are only well developed in exposures along the Daxia River drainage, especially in Dongxiang County, and less developed, or even absent, in the Guangtong River drainage.
GeoJSON
Fossils
Insectivora: Mioechinus sp., Talpidae gen. et sp. indet; Primates: Pliopithecus sp.; Lagomorpha: Alloptox chinghaiensis, Alloptox minor, Ochotonidae gen. et sp. indet.; Rodentia: Atlantoxerus sp., Castoridae gen. et sp. indet., Sayimys cf. obliquidens, Sayimys sp., Megacricetodon sinensis, Heterosminthus orientalis, Protalactaga? sp.; Carnivora: Hemicyon teilhardi, Pseudaelurus guangheensis; Proboscidea: Gomphotherium sp., Serbelodon zhongningensis, Platybelodon granger; Perissodactyla: Anchitherium gobiense, Chalicotherium sp., Hispanotherium matritense; Artiodactyla: Listriodon mongoliensis, Kubanochoerus sp., Dorcatherium sp., Moschus sp., Stephanocemas thomsoni, Palaeotragus tungurensis, Turcocerus sp. (Deng et al., 2013).
Age
Depositional setting
The Dongxiang Fm began with multi-cycle fluvial deposits and was gradually replaced by alternately shallow lacustrine purplish red mudstone and deep lacustrine cavernous marl.
Additional Information