Photoferrotrophic Bacteria Initiated Plate Tectonics in the Neoarchean

Abstract

<p>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.</p>