Sulfur and carbon isotopic evidence for metabolic pathway evolution and a four-stepped Earth system progression across the Archean and Paleoproterozoic

JR Havig, TL Hamilton, A Bachan, LR Kump - Earth-Science Reviews, 2017 - Elsevier
The Earth's mantle has provided a ready redox gradient of sulfur compounds (SO 2, H 2 S)
since the stabilization of the crust and formation of the ocean over 4 billion years ago, and …