Microbial activity preserved in 3.4 Ga colloform pyrite: A micro–scale sulfur isotope analyses

Microfossil-bearing black cherts from the ca. 3.4 Ga Strelley Pool Formation in the Goldsworthy Greenstone Belt, Pilbara Craton, offer critical insights into early Archean microbial ecosystems. In this study, we analyzed concentric colloform pyrite grains in these cherts to investigate their formation mechanisms and potential microbial involvement. The examined chert samples contain abundant organic matter and microfossils. The colloform pyrite grains, typically less than 10 µm in diameter, exhi