Abstract

The observations that Archean continental crust and the subcontinental lithospheric mantle (SCLM) have different compositions from their Phanerozoic counterparts, that komatiite extraction models for the origin of the Archean SCLM do not work, and that non-arc Archean basalts are not necessarily formed in a plume setting are used to challenge the mantle plume model for the formation of the Archean SCLM. Petrological modeling suggests that, instead, the SCLM formed at a hot ocean ridge giving rise to dense, Fe-rich basaltic ocean crust and highly depleted thick oceanic lithosphere. Typically this lithosphere would subduct, but where slab melting and tonalite-trondhjemite-granodiorite (TTG) production took place, the SCLM coupled to felsic crust would be sufficiently buoyant to be conserved. Thus Archean SCLM is transposed normal Archean oceanic lithosphere created at a hot ridge.

You do not currently have access to this article.