Photoferrotrophic Bacteria Initiated Plate Tectonics in the Neoarchean

Abstract

Plate tectonics distinguishes Earth from the other terrestrial planets but its initiation mechanism and onset time are debated. We propose plate tectonics was initiated by the deposition of magnetite-rich banded iron formations (BIFs) through biogeochemical iron cycling in Neoarchean oceans. In the photic zone of proto-continental margins, photoferrotrophic bacteria efficiently oxidized the dissolved Fe(II) and induced massive precipitation of ferric oxyhydroxide, which would rapidly react with Fe(II)-rich hydrothermal fluids from coeval vigorous volcanism in Neoarchean oceans to produce magnetite-rich BIFs. Mechanical models demonstrate that the localization of high-density BIF deposition near proto-continents induces collapse of the lithosphere and can initiate the earliest subduction. The peak deposition of BIFs in 2.75–2.40 Ga provides a time constraint on the inception of plate tectonics.

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