LOWER TRIASSIC VOLCANOGENIC FORMATIONS OF THE PRONCHISHCHEV RIDGE (NORTH OF CENTRAL SIBERIA)
The volcanogenic formations of the middle part of the Pronchishchev ridge are considered. Based on new data from the lithological, petrographic, geochemical studies of igneous and volcanogenic sedimentary rocks and stratigraphic studies of the Upper Permian-Lower Triassic terrigenous strata that enclose them, a model of their spatial relationship is proposed. It is shown that the dolerite body and the adjacent tuff breccia in the field of development of Upper Permian rocks as well as tuffite gravelites in the field of Lower Triassic rocks are a single complex of formations of different parts of the diatreme. The time of implantation of the diatreme is defined as the beginning of the Late Olenek. The wide development of vent facies dolerites in the diatreme may indicate the repeated activation of the supply channel.