Recurrent Early Triassic ocean anoxia

The Early Triassic record, from the Smithian stratotype, shows that the organic carbon isotope record from northwest Pangea closely corresponds to major fluctuations in the inorganic carbon records from the Tethys, indicating truly global perturbations of the carbon cycle occurred during this time. Geochemical proxies for anoxia are strongly correlated with carbon isotopes, whereby negative shifts in delta C-13(org) are associated with shifts to more anoxic to euxinic conditions, and positive shifts are related to return to more oxic conditions. Rather than by a delayed or prolonged recovery, the Early Triassic is better characterized by a series of aborted biotic recoveries related to shifts back to ocean anoxia, potentially driven by recurrent volcanism.