“…Notably, the absence of consistently sizeable fractionations in 34 S has been regarded as evidence for a limited importance of biological sulfur cycling in Archean sedimentary surface environments (e.g., Strauss et al, 2003), despite individual reports of highly 34 S-depleted pyrite in Paleoarchean sedimentary rocks (e.g., Ohmoto et al, 1993;Shen et al, 2001Shen et al, , 2009Philippot et al, 2007;Wu and Farquhar, 2013) and the notion from molecular biology that bacterial sulfate reduction represents an ancient metabolic pathway (Shen and Buick, 2004;Blumenberg et al, 2006;Philippot et al, 2007;Ueno et al, 2008;Shen et al, 2009;Johnston, 2011). Several recent reports of highly 34 S-depleted pyrite occurrences of early Archean age (e.g., Philippot et al, 2007;Ueno et al, 2008;Shen et al, 2009;Wacey et al, 2011a,b;Roerdink et al, 2013) strengthen the case for early biological sulfur cycling, even utilizing diverse metabolic pathways such as bacterial sulfate reduction, elemental sulfur reduction, elemental sulfur disproportionation, and sulfide oxidation.…”