Crustal structure of a Proterozoic craton boundary: East Albany-Fraser Orogen, Western Australia, imaged with passive seismic and gravity anomaly data

The simplest interpretation of the imaged crustal structure is that the Gunnadorrah Seismic Province is underthrust beneath the Yilgarn Craton, likely as a consequence of crustal shortening during accretion further east. The imaged geometry overall appears to show a wedge of Archean lower crust that was driven between the exhumed Fraser Zone and the Gunnadorrah Seismic Province, effectively splitting the Paleo- to Mesoproterozoic crust of the east Albany-Fraser Orogen. The vertical splitting of Proterozoic crust by a cratonic crustal wedge, comparable to what we image in this study, may be a process that contributed to forming many craton margins around the world.