This file documents the sulphur isotope data, and the manner in which it has been processed, to supply the reference data for isotope domains of the Isotope biosphere domains GB (V1) map. It includes a summary of the analytical methods used to determine the isotope ratios though time.

Pyrite samples from selected sedimentary organic-rich formations or associated igneous and metamorphic rocks were analysed by conventional S isotopic analysis. Pyrites were measured in order to provide insights into their origin. Light and variable S isotope compositions in pyrite have been used to infer the influence of sulphate-reducing bacteria (and subsequent Se precipitation by sulphate-reducing microbes), whereas heavier S isotope compositions indicate a non-biological origin (i.e. physical and chemical diagenesis).