Carbonatites from Eastern Paraguay and genetic relationships with potassic magmatism: C, O, Sr and Nd Isotopes

Geochemical characteristics were systematically determined for Early Cretaceous samples of carbonatitic rocks from Eastern Paraguay (Rio Apa, Amambay and Central Provinces). The data show that all the occurrences have an enriched isotopic signature and that the carbonatites have negligible or absent...

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Bibliographic Details
Published in:Mineralogy and petrology 1997-03, Vol.61 (1-4), p.237-260
Main Authors: Castorinal, F., Censi, P., Comin-Chiaramonti, P., Piccirillo, E. M., Alcover Neto, A., Gomes, C. B., de Almeida, T. I. Ribeiro, Speziale, S., Toledo, M. C. M.
Format: Article
Language:English
Subjects:
Basins
Carbonates
Cretaceous
Crystallization
Geology
Isotopes
Magma
Mineralogy
Trace elements
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Summary:Geochemical characteristics were systematically determined for Early Cretaceous samples of carbonatitic rocks from Eastern Paraguay (Rio Apa, Amambay and Central Provinces). The data show that all the occurrences have an enriched isotopic signature and that the carbonatites have negligible or absent crustal signature. A petrogenetic model (parent liquids, fractional crystallization, hydrothermal interactions and weathering) is proposed as a function of incompatible trace element, stable (O-C) and radiogenic (Sr-Nd) isotope variations with the aim to test the significance of carbonatitic complexes as a marker of the metasomatized subcontinental lithospheric mantle. The results indicate that the carbonatites and primary carbonates from eastern Paraguay, and those from the north eastern Paraná Basin (SE Brazil), were affected by metasomatic events distinct in time and composition.[PUBLICATION ABSTRACT]
ISSN:0930-0708
1438-1168
DOI:10.1007/BF01172487