Fig. 4. Summary of two alternative interpretations of the evolution of the northwest margin of the Yilgarn Craton.

a Subduction beneath the northwest Youanmi Terrane of the Yilgarn Craton, with the related emplacement of boninitic rocks and sanukitoids, terminated with docking of the Narryer Terrane, and left a remnant scar in the uppermost mantle. The two-stage collision of the Glenburgh Terrane with the Yilgarn Craton^36,47 created the Erabiddy Shear Zone (ESZ), and further obducted the Narryer Terrane onto the lower crust of the Youanmi Terrane, a process which largely concluded with the intracratonic Capricorn Orogen. b During assembly of the West Australian Craton the Glenburgh Terrane was thrust beneath the Narryer Terrane, which had previously docked with the Youanmi Terrane during the Neoarchaean. In the subsequent Capricorn Orogen, the Glenburgh Terrane was partly subducted beneath the edge of the lithospheric root of the Yilgarn Craton, creating the seismic reflectors that mark the top of deeply underthrust continental crust. The obduction of the Narryer Terrane largely terminated at this time. v—indicates Archaean volcanic rocks with arc affinity.