Heterogeneity in syntectonic granitoids emplaced in a major shear zone, southern Brazil

Two granitoid associations were emplaced during the development of the Major Gercino Shear Zone in eastern Santa Catarina, southern Brazil. The 614 Ma Fernandes Granitoid Association is composed mainly of hornblende syenogranites including A-type, and alkali-calcic and calc-alkaline types. Initial S...

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Bibliographic Details
Published in:Journal of South American earth sciences 2011-12, Vol.32 (4), p.369-378
Main Authors: Passarelli, Cláudia Regina, McReath, Ian, Stipp Basei, Miguel Ângelo, Siga, Oswaldo, da Costa Campos Neto, Mário
Format: Article
Language:English
Subjects:
Major Gercino shear zone
Sr isotopic heterogeneity
Syntectonic granitoid associations
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Summary:Two granitoid associations were emplaced during the development of the Major Gercino Shear Zone in eastern Santa Catarina, southern Brazil. The 614 Ma Fernandes Granitoid Association is composed mainly of hornblende syenogranites including A-type, and alkali-calcic and calc-alkaline types. Initial Sr isotope ratios are heterogeneous, but systematic isotopic and element variations suggest that different source rocks produced magmas which underwent mixing and fractional crystallization. The Rolador Granitoid Association of biotite-bearing granodiorite is less isotopically heterogeneous, but systematic isotopic and element variations are not obvious. ► The Major Gercino shear zone (MGSZ) controlled the emplacement of two granitoid associations. ► Isotopic and geochemical data suggest magma mixing or assimilation-fractional crystallization in the granitoids genesis. ► The Mesoproterozoic model ages of the granites corroborate to the lithosphere-scale of the MGSZ. ► Different crustal rocks were involved in the magma genesis.
ISSN:0895-9811
1873-0647
DOI:10.1016/j.jsames.2011.03.002