Spatial distribution and speciation of sulfur in Ediacaran limestones with μ-XRF imaging and XANES spectroscopy: Implications for diagenetic mobilization of sulfur species

•Shibantan limestone contains maximum 1237 ± 315 ppm of organic sulfur.•Iron limitation enhanced organic matter sulfurization in Shibantan limestone.•Microbial activity induced large CAS content variation in Shibantan limestone.•CAS content decreased during marine and meteoric diagenesis.•Organic sulfur content in limestone matrix decreased during marine diagenesis.