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New data on biostratigraphy, sedimentology and tectonics of the Russian Far Eastern region (Lower Amurian terrane) are presented. This study shows that sedimentary sequence of the terrane consists of interbedded Radiolaria‐bearing siliceous and volcaniclastic sediments spanning an interval of over 90 million years. It is shown that accumulation of radiolarian deposits on an oceanic plate was associated with alkaline (intraplate) volcanism in the Jurassic, while the plate was drifting, and with some arc volcanism during the Early Cretaceous. The younger siliceous rocks contain volcaniclastic material and indicate that the studied sequence approached the trench in the Early Cretaceous (Hauterivian‐Barremian) and became accreted in the late Albian–early Cenomanian. We describe and illustrate radiolarian species extracted from 21 samples. A taxonomic list of 194 taxa and nine plates of Jurassic–Early Cretaceous Radiolaria are presented.

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The composition of sandstones constituting different structural stages of the Jurassic accretionary wedge in the Samarka (upper and middle? structural levels in the Lyamfana Creek and Katen River basins, respectively) and Nadan'khada-Bikin (lower level in the Ulitka River basin) terranes of the Sikhote Alin region reflects changes in provenances and tectonic settings of the near continental sedimentation basin in different periods of the wedge formation. In the terminal Middle Jurassic (Lyamfana Creek), the region was dominated by the subduction regime with sedimentary material transported from the eroded part of the con tinental margin magmatic arc. During the Kimmeridgian-Tithonian (Katen River), erosion of granitoid batholiths of the arc exposed blocks of the crystalline basement along strike slip faults. In the Tithonian-Ber riasian period (Ulitka River), the role of these blocks increased, suggesting intensification of oblique subduc tion or development of transform faults during the accretion.

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