AUSTRALIA/Proterozoic 211 Figure Assembly of the North Australian and South Australian cratons, 1900 1730 Ma metasedimentary gneiss in the Mullingarra Complex has been dated to $2181 Ma (Figure 2) This is consistent with Sm–Nd model ages of 2280–2030 My from the Northampton and Mullingarra complexes, and boreholes in the Perth Basin, indicating the involvement of Early Palaeoproterozoic crust in the evolution of the orogen North Australian Craton In the North Australian Craton, the presence of probable Archaean to Early Palaeoproterozoic cratons and continental blocks within the basement is inferred from geophysical datasets Latest Neoarchaean basement is exposed as granite and granite gneiss within the Rum Jungle and Nanambu complexes in the Pine Creek Orogen (Figure 2) These basement inliers are overlain by arkosic rocks of the Namoona Group and the shallow-marine carbonates and mudstones and siltstones of the Mount Partridge Group deposited before $1885 Ma Archaean crust of the Lucas Craton is also present as inliers partly covered by arkosic and conglomeratic rocks within the Browns Range Dome and the Billabong Complex in the Granites–Tanami Complex (Figure 2) The presence of further concealed Archaean crust that may be as old as $3600 My is indicated by Sm–Nd and Pb isotopic data, together with a U–Pb detrital zircon studies A widespread orogenic event took place throughout the North Australian Craton between 1910 and 1790 Ma This event, originally defined with a shorter duration (between 1870 and 1840 Ma), has been termed the ‘Barramundi Orogeny’ It was interpreted as an intracratonic event involving a linked polygonal system of rifts and sag basins, which evolved rapidly to became the sites of crustal shortening, voluminous magmatism, and high-temperature/low-pressure metamorphism More recent interpretations have suggested that the ‘Barramundi Orogeny’ represents a series of linked collisional events that assembled the North Australian Craton Based on similarities that can be recognized with the evolution of the TransHudson Orogen, the North Australian Craton may have been originally contiguous with Laurentia, which would have lain to the north