Lithospheric mantle evolution beneath northeast Australia

New in situ analyses of Re–Os systematics in single grains of sulfides in Cainozoic basalt-borne spinel lherzolite xenoliths from the Chudleigh Province (Australian craton) and Atherton Province (Tasman Fold Belt) are reported. The sulfide data and previously reported U–Pb and Hf-isotope data for detrital zircons and zircons from granitoids (Murgulov et al., 2007; 2009) show correlations between mantle events and crustal magmatism in northeast Queensland, Australia. About half of the analysed sulfide grains have sub-chondritic 187Os/188Os (0.1130–0.1252) and 187Re/188Os (0.0214–0.2061), suggesting preservation of their isotopic signatures during subsequent infiltration of asthenospheric silicate melts/fluids. Collision and accretion processes have probably initiated a melt-extraction event followed by cratonic lithosphere stabilisation at ~ 2.2 Ga (TMA model age). Metasomatism of the mantle lithosphere most likely involved infiltration of asthenospheric melts/fluids during lithospheric thinning and rifting beneath the Chudleigh Province at ~ 1.82 Ga, 0.81 Ga and 0.35 Ga (TRD Rhenium-depletion model ages), beneath the Atherton Province at ~ 1.75 Ga and 0.44 Ga (TRD), and during suturing at ~ 1.23 Ga (TRD), an event recorded beneath both provinces. In the Georgetown Inlier TRD model ages coincide with episodes of granitoid production and demonstrate a close temporal linkage between events in the cratonic lithospheric mantle and crust. However, such linkages cannot be demonstrated in the Tasman Fold Belt; no ~ 0.44 Ga, 1.23 Ga or 1.75 Ga granites outcrop in this region, and the shallow part of the subjacent lithospheric mantle (~ 27 km depth) experienced a younger (~ 0.44 Ga) metasomatic event not observed in the deeper lithosphere (~ 49 km depth, ~ 1.75 Ga). The younger event may be associated with the reactivation of ancient lithospheric sutures during mantle upwelling and back-arc rifting. The older events may imply that the edge of the cratonic lithospheric mantle root, metasomatised at ~ 1.75 Ga and 1.23 Ga, was rifted during a younger event (~ 0.44 Ga?). Its scattered fragments have been embedded at greater depth within the lithospheric mantle beneath the Atherton Province following collision, accretion and lithosphere suturing.

Research highlights
► Melt-extraction and lithosphere stabilisation in Queensland at ~ 2.20 Ga.
► Metasomatic events beneath the craton at ~ 1.82 Ga, 1.23 Ga, 0.81 Ga and 0.35 Ga.
► Linkage between events in the lithospheric mantle and crust of the Australian craton.
► 1.75 and 0.44 Ga metasomatism of the lithospheric mantle beneath the Tasman Belt.
► Coincidence of the 1.23 Ga metasomatic event beneath the craton and Tasman Belt.