Transition towards plate tectonics tracked in the metamorphic signature of Neoarchean synmagmatic transpression

Secular mantle cooling has progressively strengthened Earth’s lithosphere, enabling a variety of tectonic styles. The emergence of transpressional orogens in the Neoarchean is interpreted to reflect this strengthening, during a transitional phase leading to plate tectonics. However, direct constraints on lithospheric strength remain limited due to the fragmentary Archean rock record and the scarcity of structurally and temporally constrained metamorphic data. Here we present metamorphic data from two major Neoarchean shear zone networks in the transpressional Yilgarn Orogen (Western Australia), showing shearing events with vertical components of displacement of ~10 km, and burial–exhumation rates comparable to those in Phanerozoic orogens. Our findings support numerical predictions of a mechanically strong Neoarchean lithosphere capable of sustaining significant orogenic thickening. This provides new constraints on the rheology of early continental lithosphere and offers insight into the geodynamic processes that preceded the full establishment of plate tectonics.