Organic carbon isotopic record across the Triassic-Jurassic boundary in Austria and its bearing on the cause of the mass extinction

Abstract

Carbon isotope analyses of total organic carbon across the Triassic-Jurassic boundary in the classic section of Kendelbach, Austria, show that a positive excursion in δ13C values of organic carbon in the boundary marl correlates with a negative excursion in δ13C values in carbonates. In this section, the change in isotope values is inferred to be the result of diagenesis with no evidence of any primary change that could relate to bioproductivity. This and other evidence do not support the claim that there was a fall in productivity associated with the end-Triassic mass extinction, possibly caused by bolide impact.