Sylvain Richoz

Much attention has been given to the negative δ¹³C anomaly nearly coincident with the Permian-Triassic boundary. New data indicate a stepwise decline in δ¹³C initiating before the Latest Permian extinction event followed by highly variable δ¹³C values during the remaining Early Triassic. δ¹³C values appear much less erratic as global metazoan diversity increased in the Middle Triassic. Given the previously unappreciated magnitude of isotopic change and the number of large δ¹³C excursions that occurred during the Early Triassic, catastrophic mechanisms like methane release/bolide impact become less attractive to explain the Early Triassic carbon isotopic record as a whole.