Subcontinental lithospheric mantle

The modern understanding of the Earth's upper mantle is that there are two distinct components - the lithospheric part and the asthenosphere.

The lithosphere, which includes the continental plates, acts as a brittle solid whereas the asthenosphere is hotter and weaker due to mantle convection.

The trace element composition of these xenoliths suggest mixing between the two different layers of subcontinental mantle.

[4] If the primitive mantle is the starting composition for this SCLM formation event, subducting slab would be composed of TTG crust, then the removal of basaltic melt and the enrichment of the mantle wedge with felsic melts could explain the formation of the depleted Archean subcontinental lithosphere.

The mechanism of arc subduction is well understood to be the location where new continental crust is formed and is presumably also the site of subcontinental mantle genesis.