Archean Geodynamics Underneath Weak, Flat, and Flooded Continents
Patrice Rey, Nicolas Coltice, Nicolas Flament
Abstract
Although a significant volume of crust was extracted from the mantle early in Earth’s history, the contribution of felsic rocks to the sedimentary record was minimal until ~3.0 Ga. On a hotter Earth, this conundrum dissipates if we consider that the felsic crust was buried under thick basaltic covers, continents were flooded by a near-global ocean, and the crust was too weak to sustain high mountains, making it largely unavailable to erosion. Gravitational forces destabilized basaltic covers within these weak, flat, and flooded continents, driving intra-crustal tectonics and forcing episodic subduction at the edges of continents. Through secular cooling, this dual-mode geodynamics progressively transitioned to plate tectonics.