Sed i en tolog ica l fea tures and b iostra tigraphy of Jura ssic /Cretaceous deposits in con tinen ta l ba sin s in Pr iam ur ie , Far Ea st Russia

The paper describes the sedimentary features and biostratigraphy of the transitional Jurassic to Creta2 ceous deposits in the continental basins of Priamurie formed after the collision between the Siberian and North China blocks. In Upper Priamurie, the collision occurred in the late Early Jurassic as dated by the emp lacement of the post2collisional granites ( 191 Ma) . W hile in Lower Priamurie and W est Priokhotie it could take p lace in the late M iddle Jurassic on the basis of fossil evidence from an accretionary turbidite comp lex. This event reflec2 ted the environmental change from coastal2 marine to alluvial p lains, often boggy, where coals accumulated. The environmental change is in harmony with that of biota. Systematic study of floral and spores /pollen assembla2 ges, particularly in the sections of interbedded marine and non2 marine deposits, makes clear the chronostrati2 graphic succession of floral associations and shows the possibility of their app lication for subdivision and correla2 tion of the continental deposits of Priamurie. The coastal2 marine environment of the residual post2collisional sublatitudinal basins in the western part of Priamurie (Upper Amur and Dep basins) was rep laced by the conti2 nental in the late M iddle Jurassic and in the eastern part in the Berriasian2 Valanginian ( Torom Basin) . Sim ilar environmental change commenced in the submeridional rift basins: the Bureya Basin in the Callovian and the Partizansk Basin in the Hauterivian. Changes in ecosystem s occurred frequently during the M iddle Jurassic22 Ne2 ocom ian, but the most substantial changes took p lace in the late M iddle Jurassic and in the end of Late Juras2 sic.