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Lithospheric mantle evolution beneath northeast Australia
被引:8
|作者:
Murgulov, Valeria
[1
]
Griffin, William L.
[1
]
O'Reilly, Suzanne Y.
[1
]
机构:
[1] Macquarie Univ, Dept Earth & Planetary Sci, GEMOC ARC Natl Key Ctr, N Ryde, NSW 2109, Australia
来源:
关键词:
Mantle Iherzolite xenoliths;
Northeast Queensland (Australia) lithosphere;
Upper mantle sulfides;
Dating mantle events;
Crust and mantle linkage;
RE-OS SYSTEMATICS;
SIDEROPHILE ELEMENT GEOCHEMISTRY;
SPINEL PERIDOTITE XENOLITHS;
IN-SITU;
ISOTOPE SYSTEMATICS;
ULTRAMAFIC XENOLITHS;
ABYSSAL PERIDOTITES;
DETRITAL ZIRCON;
ORTHO-PYROXENE;
TRACE-ELEMENT;
D O I:
10.1016/j.lithos.2011.03.002
中图分类号:
P3 [地球物理学];
P59 [地球化学];
学科分类号:
0708 ;
070902 ;
摘要:
New in situ analyses of Re-Os systematics in single grains of sulfides in Cainozoic basalt-borne spinet Iherzolite 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 Os-187/Os-188 (0.1130-0.1252) and Re-187/Os-188 (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 similar to 2.2 Ga (T-MA 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 similar to 1.82 Ga, 0.81 Ga and 0.35 Ga (T-RD Rhenium-depletion model ages), beneath the Atherton Province at similar to 1.75 Ga and 0.44 Ga (T-RD), and during suturing at similar to 1.23 Ga (T-RD), an event recorded beneath both provinces. In the Georgetown Inlier T-RD 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 similar to 0.44 Ga. 1.23 Ga or 1.75 Ga granites outcrop in this region, and the shallow part of the subjacent lithospheric mantle (similar to 27 km depth) experienced a younger (similar to 0.44 Ga) metasomatic event not observed in the deeper lithosphere (similar to 49 km depth. similar to 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 similar to 1.75 Ga and 1.23 Ga, was rifted during a younger event (similar to 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. (C) 2011 Elsevier B.V. All rights reserved.
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页码:405 / 422
页数:18
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