Depletion, cryptic metasomatism, and modal metasomatism of central European lithospheric mantle: evidence from elemental and Li isotope compositions of spinel peridotite xenoliths, Kozákov volcano, Czech Republic

Spinel peridotite xenoliths in 4.1 Ma basanite lava at Kozákov volcano vary in equilibration temperature from 675 to 1,135 °C and provide a continuous sample of lithospheric mantle from the Moho to a depth of ~82 km. The sub-Kozákov mantle is layered, consisting of an upper equigranular layer (UEL) from 32 to 45 km, an intermediate protogranular layer (PGL) from 45 to 66 km, and a lower equigranular layer (LEL) below 66 km. Relative to primitive mantle, all three layers are depleted in major incompatible elements and heavy rare earth elements, with the UEL being most depleted among the three layers, consisting of harzburgite and having experienced >15 % fractional melting. In contrast, the PGL and LEL experienced