Shikang Fm
Type Locality and Naming
It was named by the Regional Survey Expedition of Hunan Province in 1976. The naming section is located in the vicinity of Shikang area 2 km east of Wenjia City, Liuyang County, Hunan Province.
Synonym: （石康组）, According to Geol. Formation Names of China (Springer), in some usages, the lower part is includes the conglomerate-sandstone of Zaoshang Fm of basal Jurassic.
Lithology and Thickness
It is characterized by alternating layers of grey-black silty mudstone and sandy mudstone in association with dark-grey medium-, and thin-bedded fine-grained quartz-sandstones, with its basal part representing grey-white thin-, to thick-bedded arkosic quartz-sandstone, with a total thickness of about 68 m.
Relationships and Distribution
Lower contact
It is in a conformable contact with the underlying Zaoshang Fm of uppermost Triassic-early Jurassic (?) conglomerate and sandstone.
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Gaojiatian Fm
Regional extent
In the Zhuzhou, Hengyuan, Lingling and Dongkou regions, the formation is characterized by the occurrence of an alternating layer of grey-black thin-bedded siltstones in association with silty mudstones, being rich in siderite concretions, and containing with 2-3 coal beds. Its basal part is composed of quartzose fine-grained sandstone and pebble-bearing sandstone, with a thickness commonly of 35-138 m, yielding fresh-water bivalves belonging to the Sibireconcha shensiensis-Utschmiella tungussica assemblage, and plant fossils belonging to the Marattiopsis-Otozamites assemblage. It is in a disconformable contact with the underlying Zaoshang Fm, or overlies still older strata directly.
GeoJSON
Fossils
It yields marine bivalves and plant fossils, with the marine bivalves being represented by the Xinyuella or the Hiatella assemblage whose major members are Xinyuella liuyangensis, X. pinlingensis, X. glotta, Hunanella spp. and Isognomon? spp.
Age
Depositional setting
Additional Information