Liushu Fm
Type Locality and Naming
Linzia Basin. The type section (35°26'23″N, 103°26'37.6"E) is is located at the Liushu Village, Dongxiang County, and the reference sections are located at Maogou of the Dongyuan Township and Wangjiashan of the Jinggou Townshio in Dongxiang County. It was named by Li et al. (1995). The Liushu Fm corresponds to the lower to middle part of the Member 4 of the original Linxia Fm named by the First Regional Geologic Survey Team of the Gansu Geological Bureau in 1965.
Lithology and Thickness
The lithology of the Liushu Fm is quite uniform throughout the whole formation. It consists of light yellowish-brown carbonate-cemented siltstones intercalated with a few thin beds of mudstones and marls, developing large number of 2 to 10 cm carbonate nodules. Toward the southern Linxia Basin, more conglomerates are intercalated in the Liushu Fm. Average thickness is ca. 100 m.
Relationships and Distribution
Lower contact
It is conformable with the underlying Hujialiang Fm.
Upper contact
It is disconformable with the overlying Hewangjia Fm.
Regional extent
The Liushu Fm is widely distributed in the Linxia Basin. The thickness of the Liushu Fm varies greatly in different sections, which is mainly caused by the later erosion. For example, at the Laogou site, the thickness of the Liushu Fm is only 17 m, which is directly covered by the conglomerate of the late Pliocene Jishi Fm, indicating that the upper part of the Liushu Fm and the entire Hewangjia Fm have been eroded away. The thicknesses of the Liushu Fm are 130 m in Yangjiashan, Sanhe Township, Hezheng County, and 90 m in Shilidun. There are also some places where the thickness can be indirectly judged, such as the Liushu Fm in Huaigou and Shilei, Guanfang Township, Guanghe County, which can reach 150 m. At the southwest margin of Linxia Basin, the thickness of the Liushu Fm is nearly 200 m due to the intercalated multiple layers of gravel.
GeoJSON
Fossils
According to their position in the profile, the fossil sites of the Hipparion fauna in Liushu Fm can be clearly divided into four horizons, typified by faunas from Guonigou, Dashengou, Yangjiashan and Qingbushan. Guonigou Fauna: Rodentia: Pararhizomys hipparionum, Pararhizomyinae gen. et. sp. nov.; Carnivora: Gobicyon sp., Dinocrocuta gigantea, Machairodus palanderi; Proboscidea: Prodeinotherium sinense, Tetralophodon exoletus; Perissodactyla: Hipparion dongxiangense, Hipparion weihoense, Chalicotherium sp., Chilotherium primigenius, Parelasmotherium simplym, Parelasmotherium linxiaense, Ningxiatherium euryrhinus; Artiodactyla: Listriodon mongoliensis, Shaanxispira linxiaensis., Tsaidamotherium brevirostrum. Dashengou fanua: Rodentia: Prosiphneus sp., Pararhizomys hipparionum; Carnivora: Indarctos sp., Sinictis sp., Parataxidea sinensis, Melodon majori, Promephitis parvus, Promephitis hootoni, Ictitherium sp., Hyaenictitherium wongii, Hyaenictitherium hyaenoides, Dinocrocuta gigantea, Machairodus palanderi, Felis sp.; Proboscidea: Tetralophodon exoletus; Perissodactyla: Hipparion chiai, Hipparion weihoense, Chalicotherium sp., Acerorhinus hezhengensis, Chilotherium wimani, Iranotherium morgani, Diceros gansuensis; Artiodactyla: Chleuastochoerus stehlini, Dicrocerus sp., Samotherium sp., Honanotherium schlosseri, Shaanxispira sp., Gazella sp., Miotragocerus sp., Hezhengia bohlini.; Yangjiashan Fauna: Rodentia: Hystrix gansuensis, Pararhizomys hipparionum; Carnivora: Simocyon primigenius, Promephitis parvus, P. hootoni, Parataxidea sinensis, Pleisiogulo sp., Ictitherium sp., Hyaenictitherium wongii, H. hyaenoides, Adcrocuta eximia, Machairodus palanderi, Metailurus minor, Felis sp.; Perissodactyla: Hipparion coelophyes, H. dermatorhinum, Acerorhinus hezhengensis, Chilotherium wimani, Dicerorhinus ringstroemi; Artiodactyla: Chleuastochoerus stehlini, C. linxiaensis, Microstonyx major, Metacervulus sp., Cervavitus novorossiae, Eostyloceros hezhengensis, Euprox grandis, Honanotherium schlosseri, Palaeotragus microdon, Miotragocerus sp., Sinotragus sp, Protoryx sp., Gazella sp. Qingbushan fauna: Rodentia: Pararhizomys hipparionum, Pararhizomyinae gen. et sp. nov., Micromys sp., Hystrix gansuensis; Carnivora: Simocyon primigenius, Agriotherium inexpectans, Indarctos zdanskyi, Plesiogulo sp., Parataxidea sinensis, Promephitis parvus, Promephitis hootoni, Ictitherium sp., Hyaenictitherium wongii, Hyaenictitherium hyaenoides, Adcrocuta eximia, Metailurus minor, Metailurus sp., Machairodus palanderi, Felis sp., Pliohyrax sp.; Perissodactyla: Sinohippus robustus, Hipparion coelophyes, Hipparion dermatorhinum, Hipparion platyodus, Ancylotherium sp., Tapirus hezhengensis, Acerorhinus hezhengensis, Shansirhinus ringstroemi, Chilotherium wimani, Chilotherium anderssoni, Dicerorhinus ringstroemi; Artiodactyla: Chleuastochoerus stehlini, Microstonyx major, Metacervulus sp., Dicrocerus sp., Cervavitus novorossiae, Palaeotragus microdon, Honanotherium schlosseri, Protoryx sp., Gazella sp., Miotragocerus sp., Sinotragus sp.
Age
Depositional setting
It is interpreted as a river-lake environment. In Dongxiang, the rust-spotted siltstone is the main shallow lacustrine facies, and in Wangjiashan, it is the various-colored mudstone with subaqueous fan delta siltstone, which records the shrinking process of the ancient lake body as the climate dries up.
Additional Information