Provenance of the Middle Jurassic-Lower Cretaceous (Berriasian-Valanginian) deposits of the Lower Amur region

摘要

The petrographic and chemical study of the Middle Jurassic-Lower Cretaceous rocks of the Lower Amur region revealed the important role of granitoids in their provenance. Intermediate, mafic, and ultramafic (?) intrusive rocks, as well as sedimentary, volcanic, and metamorphic complexes were less common. The orientation of the cross bedding and casts of whirlpool pits in the Tithonian-Valanginian turbidites indicates that the provenance was located in the west and southwest. It was mainly made up of the continental granite-metamorphic blocks of the Jiamusi-Khanka-Bureya Massif. At the same time, a significant part of the provenance was occupied by the fragments of the Late Paleozoic-Early Mesozoic active continental margin.