New sedimentological, lithochemical, and biostratigraphic data were applied to describe the main part of the Inikan Formation, which is comprised in the Kuonamka Complex of the lower and middle Cambrian of the Siberian Platform. A classification of carbonaceous rocks in the Inikan and Chaya formations was proposed, based on a comprehensive approach, including textural analysis, study of geochemistry of rock-forming oxides and organic carbon, lithochemical calculations, optical petrographic, and X-ray structural data. This made it possible to clarify the structure of the overall section and the conditions under which Cambrian deposits formed. The widespread influence of volcanic activity during sedimentation in the Kuonamka Complex in the southeastern Siberian Platform was identified for the first time. The distribution of paleoseismic breccia in the section was also described, with horizons that represent good regional stratigraphic markers. Limitations in the use of the Strakhov modulus and the Nesbit-Young chemical index of alteration for characterizing sedimentation conditions of Domanikoids were revealed.
