Transition of subduction-related magmatism from slab melting to dehydration at 2.5 Ga

The Archean plate tectonics and subduction-related magmatism have been concerned for several decades. Here we investigate the Archean plate subduction from a new perspective, using the secular records of global-scale non-TTG (tonalite-trondhjemite-granodiorite) felsic rocks with arc-like geochemical affinities. The statistical results show that the La/Yb and Sm/Yb of non-TTG arc felsic rocks evolved at high values in the Archean, and decreased...