Fig. 8: Geochemical data from Otto Creek, Sverdrup Basin, Arctic Canada.

Geochemical profiles show variations in carbon isotopes (δ13Corg), total organic carbon (TOC), carbon/sulfur (C/S) ratio, and nitrogen isotopes (δ15N), and are placed in relative time sequence. K-Ar ages of cluster 3 (see Fig. 7) across the LPE and the Late Triassic (221.3 Ma) are shown. The stippled vertical green line indicates C/S ratio ~1 used to define relative changes in the redox state of the Sverdrup Basin. Prevalence of phosphate nodules are indicated5. Stratigraphic sub-units are marked by stippled lines. L.Pr. late Permian, Cha. Changhsingian, Ind. Induan.