Fig. 5.

Modeling of the positive carbon- (black) and sulfur- (gray) isotope excursion, with the gray bar indicating OAE 2 represented from 1.0 to 1.5 Ma as delineated by the characteristic C-isotope profile. In this model the initial marine sulfate concentrations were 7 mM, Δ34S was increased to –40‰, pyrite burial was doubled, and OC burial was increased 1.6-fold during the OAE. The burial of OC and pyrite was decreased progressively, and Δ34S was immediately returned to \x{2212}30‰ for 300 ka after the OAE.