Kholminka Fm
Type Locality and Naming
Khor-Dalnin zone of central Sikhote-Alin uplift
Lithology and Thickness
The Kholminka Formation is subdivided into the lower and upper members. Lower member is composed of sandstones, tuffaceous sandstones and siltstones with basal conglomerates and gravelstones and lava and tuffs in the middle part. The total thickness of the lower member is more than 700 m. Upper member is composed of silty mudstones and sandstones with rare lenses and beds of andesite tuffs and tuffits with a total thickness of 820 m.
Relationships and Distribution
Lower contact
The Kholminka Formation unconformably rests on the Middle Triassic-Jurassic siliceous-terrigenous rocks, on the Valanginian-age Klyuchi Fm or on the supposedly Jurassic basalts and basaltic andesites.
Upper contact
Major disconformity, overlain by un-named volcanic ash unit, then Dorofeevka Fm.
Regional extent
GeoJSON
Fossils
Lower Member yields fossil plants including Asplenium dicksonianum, Cladophlebis frigida, Elatides asiatica, Zamites sp., Athrotaxopsis expansa, Nilssonia sp., Onychiopsis psilotoides, and bivalves, including “Callista” ex gr. pseudoplana, “C.” sculpturata and Modiolus sp. (Markevich et al., 2000). Upper Member contains ammonite Paragastroplites ex gr. spiekeri and an assemblage of bivalves including Entolium utukokense, Thracia semiplana, T. cf. phillipsi, Pleuromya sp. ind., “Callista” pseudoplana, Ussuritrigonia cf. ussurica, Buchotrigonia sp. ind., Oxytoma camselli, Camptonectes ex gr. dattermani, Liostrea sp. ind., Modiolus sp., Lima sp. ind (Markevich et al., 2000).
Age
Depositional setting
Additional Information