Yangkyi Fm
Type Locality and Naming
It was named by the No. 1 Regional Survey Party under the Geological Bureau of Qinghai Province as the Yangkyi Group in 1974. The naming section is located in the Yangkyi area of the Gamao region, Xinghai County (ca. 35.6N, 100E), Qinghai Province.
Synonym: （羊曲组）, Yangqu Fm (spelling)
Lithology and Thickness
The formation is composed of grey, grey-white, yellow-green and purple sandstones, conglomerates and mudstones, containing coaly debris, coal seams and coal bands, with a thickness of 24-94 m.
Relationships and Distribution
Lower contact
The formation is in an unconformable contact with the underlying Triassic System (Babaoshan Gr sandstones).
Upper contact
Next younger (late Middle Jurassic) unit is the Damitan Fm (conglomerate, sandstone).
Regional extent
The formation is distributed in the Guinan and Xinghai areas, Henan Mongolian Autonomous County, and the northern part of Maduo County, Qinghai Province. Except for the naming locality, in the areas of Xinghai Hot Spring and Heishan Coal Mine the formation contains more coal beds.
GeoJSON
Fossils
It yields plant fossils such as Neocalamites cf. hoerensis, Coniopteris hymenophylloides, C. cf. tatungensis, Cladophlebis sp., Podozamites lanceolatus and Czekanowskia rigida.
Age
Depositional setting
Additional Information