Jurassic deposits of the southern part of the Irkutsk sedimentary basin

Fossil Calibrations for the Arthropod Tree of Life

“…smirnovi was found on the right bank of the Angara River, downstream of Ust'-Baley village in the Olonkovsky District of Asian Russia (Kotov, 2007). According to the presence of Osmundacidites-type plant spores, the Ust'-Baley outcrop of the Cheremkhovo or Cheremkhovskaya Formation is correlated to the late Toarcian stage of the Early Jurassic (Akulov et al, 2015). The younger boundary of the Toarcian is 174.1 Ma ± 1.0 Myr, therefore giving a minimum age of 173.1 Ma.…”

Stratigraphy of Jurassic Sediments of the Southern Siberian Platform (Russia) Studied through Lithologic and Paleobotanical Data

“…The stratigraphic sequences of these formations and their lithologic characteristics were confirmed by lithostratigraphic data in different boreholes and natural sections [1,28].…”

“…Productive coal seams (thickness from 3.5 up to 10 m) are confined to this part of Upper Cheremkhovskaya (Ust'-Baleiskaya) Subformation overlaps in concordance with the Middle Cheremkhovskaya Subformation, and more than a half of the former is composed of fine-and medium-grained sandstones with lenses of siltstones and mudstones. Lower boundary line is drawn in the bottom of sandstones of channel facies [1] and it is observed within opencasts of developed coal deposits (Cheremkhovo, Glinki, and Mugun; Figure 2 Prisayanskaya Formation is less abundant relative to the Cheremkhovskaya one which is overlapped with conformability by it.…”

Age of the coal accumulation in the Irkutsk basin based on accessory zircon dating in the Azeisk deposit tonstein (LA-ICP-MS)

“…The age of the Irkutsk basin sediments was determined by the biostratigraphic method, which gives a rather wide time interval. At that, while the lower limit of the sedimentation onset is determined in the Pliensbachian age (Akulov et al, 2015;Kiritchkova et al, 2017;Saks et al, 1981;Skoblo et al, 2001), the upper one remains drifting from the Aalenian to the Bajocian age (Akulov et al, 2015;Kirichkova et al, 2016;Saks et al, 1981;Skoblo et al, 2001). The age of the sediments was determined mainly by plant residues Mashchuk, 2018, 2014;Kirichkova and Travina, 2000); fauna findings are rare and are mainly related to the lower sub-formation of the Prisayan Fm.…”

“…Despite the large number of publications devoted to studies of the Irkutsk basin (Adamenko et al, 1971;Akulov et al, 2015;Feinstein, 1971;Kiritchkova et al, 2017;Odintsov, 1967;Skoblo et al, 2001;Timofeev, 1970), questions related to the age and position of the stratigraphic units still remain undetermined (Fig. 2).…”