... and high terraces and deltaic sand deposition. As a result of tectonic activity, the outlet of Baikal through the paleo-Manzurka valley to the Lena River was barred 2.0–0.5 Ma ago and a new outlet appeared through the Ilcha-Irkut valley to the Yenisei system (0.5–0.06 Ma ago). This outflow was substituted...

... of the Elovka and Nilov spurs — interbasinal bulkheads. The gently dipping plains made up of these deposits either merge with the surface of low terraces on the right bank of the Irkut River or submerge beneath the bog-lacustrine sediments of recent subsidence zones in the Tunka basin. Here, they overlay...

..., which are low-elevated steps (fault blocks), are cut with cobbly and bouldery river terraces, the first terrace being of erosional origin. This setting is observed especially within the Kharadaban step that separates the Turan and Mondy basins, in the sides of a narrow antecedent valley of the Irkut...

... river flow ( Fainshtein, 1971 ). Widespread alluvium composed of outsize conglomerate with layers of outsize gravel, which was deposited by streams along mountain valleys, was found in the pra-Angara headwaters on the Lake Baikal shore and partly in the fore-Irkut basin ( Timofeev, 1970 ). According...

... above its level. The basin floor is cut by erosional incision reaching 50 m in the Bystraya River valley (Irkut catchment) and exceeding 100 m in the Ilcha River valley (Baikal catchment) ( Fig. 9 ). Fig. 8. Neotectonic framework of Tunka rift and its surroundings. 1–4 , intermontane basins...

... River between Moty and Vvedenshchina villages (KA19-002–KA19-054 in Fig.  1 b). Our study focuses mostly on the Irkut Formation and the lowermost 27 m of the Usol’e Formation, which are documented in the upper part of the Shaman Cliff (lower 45 m of the Irkut Formation) and in the exposures along...

... developed among the Archean rocks in the middle reaches of the Kitoi River and are interpreted as rocks of the shoshonitic series ( Ivanov et al., 2019 ). The Malyi Zadoi peridotite–gabbronorite massif is located in the southwest of the Irkut block between the Toisuk and Kitoi rivers among Archean mafic...

... of the Kirenskian – Kudrinian Horizon are local and appeared only in the Irkut amphitheater (including the basin of the upper Lena River) as a result of the drastic shoaling of this part of the paleobasin, the expansion of the littoral and island lands, and the formation of coarse-clastic terrigenous rock strata...

... grains with similar ages and D = 7–17%. These zircons show wide variations in the contents of U (63– 647 ppm) and Th (27–669 ppm) and Th/U values (0.07–1.0); most of them are dark, unzoned in CL images or have patchy zoning. In the southeastern Irkut terrane (Baikal shore, Irkut River basin...

... deposits in the Gargan block of East Sayan. Similarities are observed in the sedimentation and tectonic evolution of the regions. The conditions of the deposition of quartzites (forearc basins within siliceous-carbonate rocks with slight tholeiitic volcanism and a small amount of terrigenous material...

... in the Kitoi River area), b – rocks of the Cis-Sayan uplift and the western part of the Sharyzhalgai uplift. Geochemical data: 1 – Baikal uplift ( Table 3 and ( Shokhonova et al., 2010 ; Donskaya et al., 2023 )), 2 – Irkut block of the Sharyzhalgai uplift (except for lamprophyres of small massifs...

... of the Chelonchen Brook. It was previously shown, however, that the Chelonchen member is overlain by a sandstone bed in this exposure. An analog of the Chelonchen member everywhere from Patom Village up to the lowermost reaches of the Bol’shoi Patom River and in the basin of the Zhuya River is a turf-covered...

... was the Munku-Sardyk Ridge (part of the Big Sayan Range) with the adjacent part of the Oka Plateau. Glaciers descended from this region along the Oka valley to the northwest and along the Irkut river valley to the Mondy Basin. The thickness of the glacier filling the Mondy Basin was >300 m, whereas its width...

..., which has remained poorly studied until recently. This paper presents new data on the composition and age of granitoids in the northwestern part of the Kitoy block (Onot River basin). The main goals of the paper are to reveal the sequence of granite emplacement and rock genesis and to correlate...

... , Paleoproterozoic orogenic belts. B , scheme of blocks of the Sharyzhalgai uplift. Outlined is the geological scheme shown in C . In the southeast of the Irkut block, two rock units were recognized in the metamorphic complex (Lake Baikal shore, Irkut River basin): metaigneous and metasedimentary...

...L.N. Urmantseva; O.M. Turkina; I.N. Kapitonov Abstract The paper presents data on high-grade silicate–carbonate rocks (calciphyres) from the Irkut block (Sharyzhalgai uplift, southwestern Siberian craton). Their origin and age were determined from the rock characteristics, U–Pb dating, REE content...

..., and weathered bedrock crops out in its eastern most highly uplifted end. Its floor surface mainly consists of low hills with flat tops at the Neogene stratigraphic level of deposition (Bystraya bed of the Anosov Formation) and encloses a set of terraces of the Irkut River and its tributaries, as well...

... of strong shoaling and high salinity of the basin, as it occurred throughout the Turukhan-Irkut-Olekma region, or, on the contrary, because of too great water depths (southern side of the Aldan complex, Dzhanda River) [ 26 ]. The subsequent transgression, which acted upon the Siberian Platform since...

... of terrigenous-carbonate-siliceous sedimentary sequences of the sea basin that existed here in the Middle Riphean ( Vorob’ev et al., 2003 ; Bydtaeva et al., 2006 ; Semeikin, 2006 ; Fedorov et al., 2011 ; Makrygina and Fedorov, 2013 ; Anfilogov et al., 2015 ). The major difference in all these hypotheses...