The largest plagiogranite on Earth formed by re-melting of juvenile proto-continental crust

Abstract The growth of continental crust through melt extraction from the mantle is a critical component chemical evolution Earth and development plate tectonics. However, mechanisms involved remain debated. Here, we conduct petrological geochemical analyses on large (up to 5000 km 2 ) granitoid body in Arabian-Nubian shield near El-Shadli, Egypt. We identify these rocks as largest known plagiogranitic complex Earth, which shares characteristics such low potassium, high sodium flat rare earth element chondrite-normalized patterns with spatially associated gabbroic rocks. hafnium isotopic compositions zircon indicate juvenile source for magma. ? 18 O values suggest interaction hydrothermal fluids. propose that El-Shadli plagiogranites were produced by extensive partial melting juvenile, previously accreted oceanic this overlooked mechanism formation plagiogranite also responsible transformation into chemically stratified crust.