Lipovtsy Fm

Razdolny depression of southern Primorye Basin (S-10; NW of Vladivostok). Middle formation of the Nikan Gr

It is subdivided into two members (Volynets et al., 2016). Lower member consists of conglomerates and coarse-grained gravelly sandstones. Coal seems absent. The thickness varies from 140 to 260 m. Upper member consists mainly of fine-grained sandstones, siltstones, mudstones and coal. The lower coal bed “Rabochiy” (up to 19 m hick) has commercial significance, while the superposed coal bed “Gryaznyi” (1-2 m thick) does not. The thickness of the member is up to 350 m.

Two flora assemblages were identified in the Lipovtsy Formation (Volynets, 2005). The Early Lipovtsy flora assemblage was identified in the lower member of the Lipovtsy Formation (Volynets et al., 2016). It includes Thallites sp., Lycopodites nicanicus, Isoetites sp., Equisetites ex gr. burejensis, E. ramosus, Coniopteris burejensis, Coniopteris sp., Alsophilites nipponiensis, Onychiopsis psilotoides, Cladophlebis matonioides, C. frigida, C. sp., Lobifolia novopokrovskii, Sphenopteris ex gr. fontainei, Sagenopteris sp., Pterophyllum burejense, P. manchurense, P. sp., Dictyozamites cordatus, Nilssoniopteris robusta, Nilssonia ex gr. brongniartii, N. densinervis, N. nicanica, N. sp., Baiera ahnertii, Podozamites ex gr. lanceolatus, P. sp., Pityophyllum sp., Elatides ex gr. curvifolia, E. asiatica, Athrotaxites berryi, Athrotaxopsis expansa, Brachyphyllum japonicum, B. sp. The sporepollen assemblage is dominated by schizanthus and gymnosperms and includes Appendicisporites, Cicatricosisporites, Concavissimisporites, Impardecisporites, Trilobosporites, Pilosisporites. The range of the lower member based on both flora and sporepollen assemblages is considered as Aptian (Krassilov, 1967; Markevich, 1995; Volynets, 2005; Volynets et al., 2016; Volynets and Bugdaeva, 2017). The Late Lipovtsy flora assemblage was identified in the upper member (Volynets et al., 2016). It consists of 167 taxa including ferns (47 taxa), conifers (42 taxa), cycadophytes (38 taxa), diverse Lycopodiales. Extremely rare angiosperms, represented by leaves of Monocotylophyllum sp. and Dicotylophyllum spp. and dispersed cuticle of indeterminable platanoids, appear in the upper part of the member for the first time. The characteristic feature of this flora assemblage is the presence of Nathorstia pectinata, Dictyozamites cordatus, Cycadites sulcatus, Torreya nicanica with the significant role of “young” evolutionary advanced taxa of Osmunda denticulata, Birisia onychioides, Sequoia ex gr. reichenbachi, Taxites brevifolioides as well as the first appearance of angiosperms (Volynets et al., 2016). The spore-pollen assemblage of the upper member is represented by Roeseysporites radiatus, Lobatia involucrata, Kuylisporites lunaris, Lophotriletes babsae. The particular feature of this assemblage is the appearance of single pollen of angiosperms of Tricolpites spp., T. vulgaris, Retricolpites georgiensis, Clavatipollenites hughesii and Quercites sparsus (Volynets et al., 2016). This assemblage is considered to be upper Aptian-lower Albian (Volynets, 2006, 2013, 2014; Bugdaeva et al., 2014; Volynets and Bugdaeva, 2017).