Data on heavy minerals from the Valanginian-Cenomanian sedimentary rocks of the Lower Amur region are interpreted on the basis of actuallistic approach with the use of previous study results on heavy mineral assemblages from the modern deposits accumulated in the known plate-tectonic conditions. As a result, the following has been found out; Deposits of the Valanginian-Barremian ensimatic island arc and its adjacent marginal sea, Barremian-Albian active continental margin, and Albian-Cenomanian passive (or transform) continental margin were combined in terranes of the Lower Amur region. Major tectonic processes that resulted in these were large-scale strike-slip movements and accretion processes associated with oblique subduction, and some collisions among the arcs mentioned, continental margins, and rigid blocks of oceanic lithosphere.
The Kema terrane is a suite of Barremian(?)-Aptian to Albian volcanosedimentary rocks of Sikhote-Alin that are interpreted as deposits of the back-arc basin of the Moneron-Samarga island-arc system. Compositional features of the different-type deposits indicate a near-slope depositional environment influenced by volcanic processes. Studies of slump fold orientation testify to the accumulation of material from southeast to northwest by gravitational sliding. Compositional characteristics of terrigenous rocks suggest the major provenance for detrital material was an ensialic volcanic island arc. Petrochemical characteristics of basaltic rocks indicate that the formations studied were confined to the back part of the arc.
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