**2. Methods**

**1. Introduction**

Lower and middle Jurassic continental sediments of Siberia are abundant. They are exposed along river valleys and gorges, within quarries and mine workings of the Kuznetsk, Kansk, Irkutsk, and other Coal Basins. Lower and Middle Jurassic sediments are rich in plant remains, which are important in stratigraphy and correlation of continental complex of Jurassic sediments where large coal deposits are concentrated. The Irkutsk Basin situated within the southern Siberian platform is one of them (**Figure 1**). Three structural and facies zones: Prisayan piedmont trough, Platform limb, and Angara‐Koty intermountain area are clearly distinguished within it [2]. According to the regional stratigraphic scheme, the Jurassic sediments of the Platform limb and Prisayan piedmont trough are subdivided into three for‐ mations: Cheremkhovskaya, Prisayanskaya, and Kudinskaya. Cheremkhovskaya Formation

82 Seismic and Sequence Stratigraphy and Integrated Stratigraphy - New Insights and Contributions

**Figure 1.** Layout of the studied key sections. 1—the left bank of the Bol'shaya Belaya river at 200 m below the railway bridge in the Taiturka settlement (GPS: N52°86.242'; E103°49.371'); 2—the right bank of the Zalari river, on the opposite side of the Zalari settlement (GPS: N53°55.924'; E102°55.199'); 3—the Cheremkhovo coal deposit (GPS: N53°20.329'; E103°11.985'); 4—the Glinki coal deposit (GPS: N53°86.684'; E102°26.406'); 5—the Mugun coal deposit (GPS: N54°43.050'; E100°18.245'); 6—the right bank of the Angara river, the Ust'‐Balei creek (GPS: N52°62.771'; E103°96.128'); 7—the right bank of the Angara river, the Tolstyi Cape (GPS: N52°63.714'; E103°93.978'); 8—the right bank of the Angara river, on the opposite side of the Tel'ma settlement (GPS: N52°70.676'; E103°77.649'); 9—the right bank of the Irkut river, Kaiskaya Gora (GPS: N52°28.331'; E104°23.019'); 10—Sinyushina Gora (GPS: N52°15.888'; E104°11.188'); 11—the Olkha river, the Smolenshchina settlement (GPS: N52°15.006'; E104°9.305'); 12—the Olkha river, Olkhinskaya Gora area; 13—the left bank of the Irkutsk water reservoir, on the opposite side of the Stroitel' dacha (GPS: N52°11.195'; E104°23.459'); 14—the right bank of the Angara river, the Topka creek valley (GPS: N52°21.289'; E104°17.282'); 15—the left bank of the Irkut river, at 2 km above the Pionersk settlement (GPS: N52°23.734'; E103°99.541'); 16—the right bank of the Kuda river, 2 km

to the north of the Zherdovka settlement (GPS: N52°66.490'; E104°57.222').

Starting in 2008 and in 2016, the authors carried out quite a number of field works in order to explore lithologic and paleobotanical peculiarities in all active coal deposits within the Irkutsk Basin (see **Figure 1**). Opencasts of three coal‐producing quarries: Cheremkhovo, Mugun, and Glinki were studied in detail. In addition, 13 exposures which are stratotypes of regional stratigraphic units were studied. The leaves of Ginkgoales and Leptostrobales were investigated by the epidermal‐cuticular method. Leaf cuticles were macerated by the stan‐ dard technique in Schultze mixture. Microslides were examined using the Olympus BX41TF light microscope and electronic scanning microscope Philips' SEM 525‐M. About one hun‐ dred pieces of ore and more than 300 microslides with unfolded pattern of leaves' compres‐ sions were studied.
