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ΔTOC Plenus column indicates change in total organic carbon (TOC%) in black shales during the Plenus interval: Up arrows indicates an increase in TOC%, down arrow indicates a decrease in TOC%. Both direction arrows indicates intermittent TOC% increase and decrease within the Plenus. Dashed lines indicate no apparent change in TOC%. Plenus interval was identified by the δ13C depletion in organic carbon (for example7).