Evolution of subcontinental lithospheric mantle beneath eastern China: Re-Os isotopic evidence from mantle xenoliths in Paleozoic kimberlites and Mesozoic basalts

Publication Type  Journal Article
Year of Publication  2008
Authors  Zhang, H. F.; Goldstein, S. L.; Zhou, X. H.; Sun, M.; Zheng, J. P.; Cai, Y.
Journal Title  Contributions to Mineralogy and Petrology
Volume  155
Issue  3
Pages  271-293
Journal Date  Mar
ISBN Number  0010-7999
Accession Number  ISI:000252294400001
Key Words  eastern china; mantle xenoliths; re-os isotopes; pges; subcontinental lithospheric mantle; re depletion ages; sino-korean craton; spinel peridotite xenoliths; western shandong province; plasma-mass spectrometry; mafic igneous rocks; north china; continent
Abstract  

The ages of subcontinental lithospheric mantle beneath the North China and South China cratons are less well-constrained than the overlying crust. We report Re-Os isotope systematics of mantle xenoliths entrained in Paleozoic kimberlites and Mesozoic basalts from eastern China. Peridotite xenoliths from the Fuxian and Mengyin Paleozoic diamondiferous kimberlites in the North China Craton give Archean Re depletion ages of 2.6-3.2 Ga and melt depletion ages of 2.9-3.4 Ga. No obvious differences in Re and Os abundances, Os isotopic ratios and model ages are observed between spinel-facies and garnet-facies peridotites from both kimberlite localities. The Re-Os isotopic data, together with the PGE concentrations, demonstrate that beneath the Archean continental crust of the eastern North China Craton, Archean lithospheric mantle of spinel- to diamond-facies existed without apparent compositional stratification during the Paleozoic. The Mesozoic and Cenozoic basalt-borne peridotite and pyroxenite xenoliths, on the other hand, show geochemical features indicating metasomatic enrichment, along with a large range of the Re-Os isotopic model ages from Proterozoic to Phanerozoic. These features indicate that lithospheric transformation or refertilization through melt-peridotite interaction could be the primary mechanism for compositional changes during the Phanerozoic, rather than delamination or thermal-mechanical erosion, despite the potential of these latter processes to play an important role for the loss of garnet-facies mantle. A fresh garnet lherzolite xenolith from the Yangtze Block has a Re depletion age of similar to 1.04 Ga, much younger than overlying Archean crustal rocks but the same Re depletion ages as spinel lherzolite xenoliths from adjacent Mesozoic basalts, indicating Neoproterozoic resetting of the Re-Os system in the South China Craton.

Notes  

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URL  <Go to ISI>://000252294400001
DOI  DOI 10.1007/s00410-007-0241-5