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Archaean volcano-sedimentary rocks act as archives to understand early Earth conditions. Apart from submarine mafic-ultramafic volcanic rocks, felsic volcanic rocks, and siliciclastic rocks, they comprise orthochemical sedimentary rocks such as cherts, banded iron formation and (rare) silicified stromatolites. Traces of Archaean microbial life are retained as carbonaceous matter within carbonaceous cherts. Lensoidal microfossils studied from the Pilbara, Singhbhum and Kaapvaal cratons provide a snapshot of their planktonic lifestyle, habitats, adaptations, and earliest diversification during the Archaean. Likewise, stromatolites from the East Pilbara Terrane, Australia and Nondweni Greenstone Belt, South Africa suggest a rich and diverse benthic microbial community in primitive oceans with hostile early Earth conditions. |