The Main Geological Bodies From Sections of the Upper Triassic-Lower Jurassic of the Western Periphery of the Vilyui

Norian-Hettangian kaolinic weathering crust, - The Boidomonskaya formation, is represented by yellow, yellow-whitish and white sands and clays, it is located in the western periphery of the Vilyui syneclise; unconformably occurs, according to the data of mapping, prospecting and exploration core drilling, on diamonds on the carbonate basement of the Paleozoic in depressions of the middle and upper reaches of the ancient Paleo-Vilyui with different morphology. Its analogues, according to deep core drilling for oil and gas, are determined in a sedimentary cover under younger formations, in a buried relic of continental genesis, in the bottom of the Lower Jurassic Kyzylsyr formation of the Khapchagay stratigraphic region of the Lena-Aldan structural-facial zone. Along the western periphery of the Vilyui syneclise, in its central framing, in natural sections of the Jurassic, The Hettangian-Lower Plinsbach deposits of continental genesis have been identified, which unconformably occur on the Norian-Hettangian kaolinic weathering crust, overlain by a thick mass of marine and coastal marine rocks of the upper Plinsbach, Toarcian and lower Aalenian. Here, in the western periphery of the syneclise, these sediments are covered unconformably higher up in the section by continental Aalenian formations of the Chonskaya formation of the Chonskaya -Tunguska depression, thus marking the reference section of the paleo-Vilyui in the upper part of the river system. In its middle and lower parts, this river system is identified by the presence of the Yakutskaya formation - a typical representative of continental sediments from the vast landscapes of the paleobasin, designated by the Lena-Vilyui stratigraphic region of the Lena-Aldan structural and facial zone. These geological bodies dominate the reference sections of the Paleo-Vilyui, being the basic ones for the sections, characterizing the basal layers of the bottom of this river system, as well as the lithostratons controlling its top in this system.