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Volcanic and Hydrothermal Signs in the Rocks of Black Shale Formations
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Sixth EAGE Shale Workshop, Apr 2019, Volume 2019, p.1 - 5
Abstract
Black shales of the Bazhenov Formation are characterized by a high heterogeneity of the composition — a complex combination of carbonate, siliceous, clay, and organic phases, which alter laterally and in the section. Ash beds occur in the lower unit (Tithonian stage, Late Jurassic). Based on a detailed description of the core and complex analytical data (petrographic analysis, scanning electron microscopy with energy dispersive spectrometry, X-ray fluorescence and X-ray phase analyzes, ICP-MS, etc.) the composition, structure and genetic features of ash layers are given. The paper also discusses the carbonate microbialites of the Bazhenov Formation and the impact of hydrothermal processes on their genesis. Volcanogenic and hydrothermal phenomena could have a fundamental impact on the water transparency and other environmental factors, affect the marine biota and its mass extinction and finaly could lead to the formation of stratas with highly increased content of organic matter. Jurassic- Cretaceous global geological processes in the Western Siberia and in adjacent areas confirm the suggested assumptions.