Title of article
Lithospheric mantle evolution beneath northeast Australia
Author/Authors
Valeria Murgulov، نويسنده , , William L. Griffin ، نويسنده , , Suzanne Y. OʹReilly، نويسنده ,
Issue Information
روزنامه با شماره پیاپی سال 2011
Pages
15
From page
434
To page
448
Abstract
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.
Keywords
Gabbro , Sr–Nd correlation , Magma mixing , Eisenkappel , Eastern Alps , Plutonic suite
Journal title
lithos
Serial Year
2011
Journal title
lithos
Record number
1287658
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