Luzhki Fm

Koppi-Luzhki zone and Kema zone of Eastern Sikhote-Alin Basin

In the Koppi-Luzhki zone, the formation consists of sandstones, siltstones, less often gravelstones and conglomerates with a total thickness of up to 2300 m. In the Kema zone, it is composed of medium- to fine-grained sandstones with rare interbeds and lenses of conglomerates, gravelstones and siltstones with beds of andesibasalts and their tuffs in the lower part. The total thickness of the formation is about 550 m.

In the Koppi-Luzhki zone, the formation yields a diverse fossil assemblage including ammonites Paragastroplites cf. flexicostatus, P. ex gr. spieckeri, “Beudanticeras” ex gr. haydeni, bivalves Inoceramus salomoni, I. cf. concentricus, Pterotrigonia hokkaidoana, P. pocilliformis, Quadratotrigonia (Transitrigonia) fudsinensis, Ussuritrigonia ussurica, U. subpyriformis, U. dedalea, Panopea gurgitis, P. elongatissima, Pleuromya sikkani, Brachidontes pedernalis, “Callista” pseudoplana and other, gastropods Ovactaeonella dolium, Nerineoptyxis sp. and other, and plants Onychiopsis psilotoides, Cladophlebis frigida, C. exiliformis (Turbin, 1994; Markevich et al., 2000). Based on the presence of ammonites Paragastroplites cf. flexicostatus, P. ex gr. spieckeri and “Beudanticeras” ex gr. haydeni and gastropods Ovactaeonella dolium, the range of the formation is considered as middle Albian (Konovalov, 1976; Poyarkova and Konovalov, 1982; Markevich et al., 2000).

In the Kema zone, the formation contains abundant and very characteristic fauna including Pterotrigonia pocilliformis, Quadratotrigonia (Transitrigonia) fudsinensis, Ussuritrigonia belembeae, Inoceramus anglicus, I. concentricus, I. salomoni, Liostrea sp., Pleuromya cf. sikkani, Entolium utukokense, Thracia kissoumi (Turbin, 1994; Markevich et al., 2000; Malinovsky et al., 2002).