Coevolution of microorganisms and sedimentary rocks
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Abstract: Earth is different from other planets due to the presence of the biosphere. Microorganisms in the biosphere have played, and are playing, important roles in shaping Earth habitability due to their wide spatiotemporal occurrence, diverse metabolism functions, rapid multiplication, and great abundance. One of the critical processes is the microbial involvement of sedimentation, resulting in the biogenic formation of sedimentary rocks including banded iron formation, limestone, dolomite, phosphorite, siliceous rock,as well as some mudstones, which in turn caused the coevolution of microbes and sedimentary rocks in Earth history. Archean is dominated by the magmatic rocks, and the sedimentary rocks are mainly related to the physical processes. The banded iron formation is however related to the contribution of photoferrotrophic bacteria. Great changes occurred in Proterozoic when sedimentary rocks overthrow magmatic rocks in abundance and the diverse biogenic rocks (calcimicrobialites, dolomites) greatly increased in abundance. Microbially-induced sedimentary structures are also diverse and in great abundance. Mudstone starts to increase in abundance at the end of Proterozoic due to the development of microorganism on land which brought into coming of a new clay factory. The transition interval across Neoproterozoic and Cambrian boundary witnessed the shift from siliceous to phosphatic and finally to calcareous rocks, coincident with the evolution from prokaryotes to eukaryotic microorganisms and finally to metazoans, showing their causal relationship. In phanerozoic, dolomite shows a sharp decrease in abundance due to the metazoan expansion and its suppression on microorganisms. Green algae dominance in Paleozoic shifted to the dominance of red algae in Mesozoic and Cenozoic, favoring the expansion of calcium carbonate from shallow water to deep water. In particular, carbonate factory showed the shift from skeleton limestones to calcimicrobialites for at least 5 times, in association with the occurrence of anachronistic facies as well as MISS; these are due to the transient expansion of microbial communities immediately after the biotic crisis. Mudstones increased in abundance immediately after the development of terrestrial ecosystems due to the innovation of clay factory on land and the enhanced precipitation of clay minerals caused by the organic-induced flocculation.