Distribution of Sulfur Isotope Anomalies in the Archean: The Example of the Karelian and Siberian Cratons

摘要

The sulfur isotope anomalies increment S-33 and increment S-36 known today in ancient rocks exhibit common geochemical patterns reflected in the existence of a correlation like increment S-36 approximate to - increment S-33 for sulfides from Archean formations of Australia, Africa, and America. To understand the scale of this phenomenon, we investigated the pattern of sulfur isotope fractionation in sulfides from rocks of the Irkut Block of the Sharyzhalgai Uplift of the basement of the Siberian Craton, as well as the Leksa ore occurrences located in the Karelian Province. It was shown that the objects of our study held increment S-33 and increment S-36 isotope anomalies. This leads to the conclusion that the geochemical processes responsible for the generation of sulfur isotope anomalies are much more widespread than was assumed until now and allows us to recognize them as a phenomenon of planetary significance. The fact that the relationship between increment S-36 approximate to -1.0 increment S-33 isotope anomalies demonstrates the same characteristics as in other Archean rocks of the most ancient shields worldwide indicates the similar conditions and mechanisms for fractionation of sulfur isotopes at the stages of its transformation in an atmospheric photochemical cycle.