Dzhaur Fm

Anyui zone of central Sikhote-Alin uplift.

The Jurassic rocks in the Anyui zone are represented by the Triassic-Jurassic volcanic-terrigenous-siliceous Dzhaur Formation or by un-named siliceous-terrigenous deposits yielding radiolarians (Markevich et al., 2000). Middle Volgian-lower Valanginian rocks in the zone are represented by un-named unit containing silty mudstones, sandstones, gravelstones, conglomerates, siliceous-clayey rocks, lava and tuffs of diabase with a total thickness of up to 2500 m. It is important to note that the Jurassic/Cretaceous boundary is present in this zone.

Two assemblages of radiolarians are reported from the upper part of this section: a Kimmeridgian assemblage containing Acanthocircus cf. amissus, Mirifusus cf. mediodilatatus, Homoeparonaella sp., Eucurtidiellum sp. and an Oxfordian assemblage including Mirifusus quadalupensis, Gongylothorax oblonga, Tricolocapsa? cf. fusiformis, Eucyrtidielium sp. and Milax sp. (Richter,1986; Markevich et al., 2000). In several localities, a silty mudstones with an assemblage of Buchia including B. fischeriana, B. piochii, B. tenuicollis, B. terebratuloides, B. trigonoides conformably rests on the siliceous-clayey shale rocks with Jurassic radiolarians (Markevich et al., 2000).