Massive volcanism, evaporite deposition, and the chemical evolution of the Early Cretaceous ocean

Early Cretaceous (145–100 Ma) rocks record a ∼5‰ negative shift in the sulfur isotope composition of marine sulfate, the largest shift observed over the past 130 m.y. Two hypotheses have been proposed to explain this shift: (1) massive evaporite deposition associated with rifting during opening of the South Atlantic and (2) increased inputs of volcanically derived sulfur due to eruption of large igneous provinces. Each process produces a very...