The geological section of Bolshoi Ilek (up to 83 m high), southeast of Western Siberia, represented by Cretaceous and Quaternary systems has been reassessed. Its major part is composed with the Lower Cretaceous deposits of deltic genesis that reached 80 m thickness and characterized the Ilek Formation stratotype. During the screen washing of sand fraction the remains of fishes, lizards, turtles, crocodiloformes, dinosaurs, and mammals, typical for the Barremian - Lower Albian, have been revealed. Mesozoic strata are covered by eolian-deluvial and eluvial Quaternary deposits from 3 to 13,5 m. Three layers with mammoth fauna remains were distinguished there. The middle one is dated by 14С as ~ 22500 years ago. The observation have revealed that Bolshoi Ilek is a large landslide more than 1 square kilometre area. All of it allowed to compare it with the coeval section of Shestakovo outcrop that also exposes the part of giant landslide, caused by earthquakes more than 9 points by Richter scale, which indicates a powerful seismic event, occurred in the southeast of region at the very end of Pleistocene.
Comprehensive confirmation of tectonic nature of the anomalous sections of the Bazhenov formation and the Lower Cretaceous Achimov stratum of Western Siberia. Part 2. Clinoforms of the Lower Cretaceous deposits