U-Pb Zircon Dating of Granulite Metamorphism in the Sludyanskiy Complex, Eastern Siberia

Conventional multigrain and single-grain zircon U-Pb ages were obtained for syn- and post-metamorphic granitoids from the Sludyanskiy Complex in the South-Western Baikal region regarded as a classical Precambrian terrain in the Eastern Siberia. Single grains of magmatic zircon from the syn-metamorph...

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Bibliographic Details
Published in:	Gondwana research Vol. 1; no. 2; pp. 195 - 205
Main Authors:	Salnikova, E.B., Sergeev, S.A., Kotov, A.B., Yakovleva, S.Z., Steiger, R.H., Reznitskiy, L.Z., Vasil'ev, E.P.
Format:	Journal Article
Language:	English
Published:	Elsevier B.V 1998
Subjects:	Baikal region granulite-facies metamorphism zircon geochronology granulite-facies metamorphism zircon geochronology Baikal region
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Summary:	Conventional multigrain and single-grain zircon U-Pb ages were obtained for syn- and post-metamorphic granitoids from the Sludyanskiy Complex in the South-Western Baikal region regarded as a classical Precambrian terrain in the Eastern Siberia. Single grains of magmatic zircon from the syn-metamorphic hypersthene-bearing biotite trondhjemite and two-pyroxene trondhjemite have yielded concordant U-Pb ages of 488.5±0.6 Ma and 488±0.5 Ma. Concordant U-Pb data for zircons of metamorphic origin in the syn-metamorphic two-pyroxene trondhjemite yield an age for the peak of the granulite-facies metamorphism in the Sludyanskiy Complex as 477.6±2 Ma. The pattern of multigrain magmatic zircon samples from syn-metamorphic granitoids reflects significant Pb loss during the metamorphic episode. This came to an end before 471.1±2 Ma as demonstrated by concordant zircon data for the intrusion of post-metamorphic amphibole-two-pyroxene quartz syenite. Our zircon data establish that the granulite-facies reworking of the Sludyanskiy Complex took place during the Palaeozoic, and not during the Paleoproterozoic as was previously suggested. The age span between the intrusions of syn-metamorphic and post-metamorphic granitoids constrains the duration of the metamorphic episode to about 20 Ma.
ISSN:	1342-937X 1878-0571
DOI:	10.1016/S1342-937X(05)70830-3