Figure 2

Histogram showing zircon δ18OVSMOW values for the ca. 1.4 Ga Alatage amphibolite and gneissic granodiorite. Yellow bar represents δ18OVSMOW of zircon in equilibrium with mantle-derived melts (5.3 ± 0.6‰, 2σ); values above 6.5‰ indicate recycling of supracrustal material24,25,26. Note the amphibolite has broadly mantle-like zircon δ18O values, while the zircon δ18OVSMOW values of the gneissic granodiorite are relative high and variable.