A high-resolution carbon isotope profile through the uppermost Neoproterozoic–Lower Cambrian part of the Sukharikha section at the northwestern margin of the Siberian platform shows prominent secular oscillations of d13C with peak-to-peak range of 6-10 ‰. There are six minima, 1n-6n, and seven maxima 1p-7p, in the Sukharikha Formation and a rising trend of d13C from the minimum 1n of -8.6 ‰ to maximum 6p of +6.4 ‰. The trough 1n probably coincides with the isotopic minimum at the Precambrian-Cambrian boundary worldwide. Highly positive d13C values of peaks 5p and 6p are typical of the upper portion of the Precambrian-Cambrian transitional beds just beneath the Tommotian Stage in Siberia. A second rising trend of d13C is observed through the Krasnoporog and lower Shumny formations. It consists of four excursions with four major maxima that can be cor related with Tommotian-Botomian peaks II, IV, V, and VII of the reference profile from the southeastern Siberian platform. According to the chemostratigraphic cor relation, the first appearances of the index forms of archaeocyaths are earlier in the Sukharikha section than in the Lena-Aldan region.

The section is collected in ascending order from its base exposed at 67º12.516'N; 87º21.567'E along ~3 km upstream the Sukharikha River, a right tributary of the Enisej River in Siberia (Russian Federation). Elevation herein has a meaning different from that in topography, because the Sukharikha section is collected from inclined beds, and the geographical elevation between start and end points is much smaller.

Supplement to: Kouchinsky, Artem; Bengtson, Stefan; Pavlov, Vladimir; Runnegar, Bruce; Torssander, Peter; Young, Edward; Ziegler, Karen (2007): Carbon isotope stratigraphy of the Precambrian-Cambrian Sukharikha River section, northwestern Siberian platform. Geological Magazine, 144(3), 1-10