Archean komatiites and geotherms

Abstract

The high liquidus temperatures of Archean komatiites and the low geothermal gradients in Archean continents appear to give contradictory indications of temperatures in the Archean mantle. We resolve this contradiction in terms of an idealized model of convection in the Archean mantle. We suggest that temperatures in the Archean mantle were no more than 100°C higher than at present, that komatiites originate from the hot lower boundary layer of a non‐steady convection cell and that Archean continents were formed near subduction zones where near‐surface temperature gradients were lower than elsewhere in the convecting mantle. Show more