Ganjingzi Fm
Type Locality and Naming
Southern peninsula of Liaoning. The name Ganjingzi Fm derived from the Ganjingzi stage named by Matsushita in 1931. The typical section is situated at the section of Jiaoshufang to Sandaogou, in Ganjingzi area, the reference section is in Paoya to Yuanjiagou, in Wafangdian City, Liaoning Province.
Synonym:
Lithology and Thickness
The Ganjingzi Fm was subdivided into three parts. Lower part is composed of dark gray, medium-bedded micritic limestone and light gray to pink, medium-bedded stromatolite-bearing dolomite intercalated with dolarenite. Middle part consists of dark gray medium-bedded micritic dolomite, dolarenite, locally intercalated with chert and lenses of quartzose sandstone. Upper part is light gray to grayish white limy dolomite intercalated with stromatolite-bearing dolomite. From north to south, its thickness increases, about 409 m thick in Fuzhou and 614 to 906 m in Luda area.
Relationships and Distribution
Lower contact
The basal part conformably overlies the underlying Nanguanling Formation with a bed of light gray stromatolite-bearing dolomite.
Upper contact
In Fuzhou area, the top part is disconformably overlain by the Cambrian Jianchang Formation. However, it is in continuous sedimentary succession with the overlying Yingchengzi Formation in Luda area.
Regional extent
Southern peninsula of Liaoning. With a persistent lithology, it is widely distributed in Luda to Fuzhou area of Liaoning Province.
GeoJSON
Fossils
It yields stromatolites: Jurusania cylindrica, Baicalia f., Kussiella f., Anabaria cf. juvensis etc. Microplants: Leiopsophosphaera densa, L. infriata, L. aperta, Trachysphaeridium incrassatum, T. hyalinum, Zonospharidium minutum, Siphonophycus simplex, Eomycetopsis sp., Gloeodiniopsis lamellosa etc.
Age
Depositional setting
The Ganjingzi Formation is considered to be a limited table-land facies, with cross-beddings, wave-beddings, monoclinal beddings, scour casts and bird's-eye structures.
Additional Information