Fig. 6. A in Faunal dynamics across the Silurian-Devonian positive isotope excursions (δ C, δ O) in Podolia, Ukraine: Comparative analysis of the Ireviken and Klonk events

Fig. 6. A. Secular trends of δ13C and δ18O values in carbonate and organic matter, Δ13C and total organic carbon from section 96 near Kytayhorod village (see SOM 1). Lithology after Nikiforova et al. (1972: fig. 82), modified. Three slices E−1 to E−3 (marked by shades of grey) denote of the early Sheinwoodian (ESCIE) carbon isotope excursion: the interval E−2 corresponds to the isotopic highstand (see a widened excursion definition in Cramer et al. 2010, also Sadler 2012); E−1 and E−3 to the increasing and decreasing curve segments, respectively, and E−4 to the regional background. Note that the Ireviken biotic event (crossed band) correlates with the initial positive δ13C shift slice (E−1); the lower event boundary corresponds the last occurrence of conodont Pseudooneotodus tricornis, and the upper boundary is questionably placed above the disappearance of chitinozoan Eisenackitina cf. dolioliformis (Figs. 15, 16; see Jeppsson 1997; Nestor et al. 2002;). Approximated Δ13C levels are calculated for δ13Cvalues averaged for two stratigraphically adjacent samples, carb as shown also by a dotted line of the curve. The microfacies illustrated are marked as rectangles. B. General view of the natural outcrop in the Dniester River valley (Tarnawa tributary) near Kytayhorod village; arrow indicates the main sampled site.