A New Model of the Behavior of Sulfur Isotopes in Modern Submarine Hydrothermal Systems

Resumo

A model of the behavior of sulfur isotopes in modern hydrothermal isotope systems is suggested. It is accepted that the thermogenic sulfate reduction in the zone of interaction with rocks of the oceanic floor proceeds in a system closed in relation to the fluid. This results in Rayleigh exhaustion in relation to the ³²S isotope. In addition, this model accounts for simultaneous extraction of sulfur from the host rocks; its concentration in the total content of reduced sulfur in the fluid ranges from 0.15 to 0.06 for the submarine systems related to tholeiitic basalt and peridotite, respectively. Application of the model explains the well-known contradictions observed in the study of the sulfur isotope composition of sulfides from the deep-sea structures of the World Ocean.