Abstract We present a comprehensive overview of the geochemical characteristics and evolution of the carbonatites from the southern Brazilian Platform (Paraná Basin). The carbonatites from different complexes display large compositional variability in terms of abundances of incompatible and rare earth elements. This is in agreement with an origin from heterogeneous lithospheric sources, as confirmed by isotopic data (see Speziale et al., this issue). The characteristic major and trace element abundances of these carbonatites present compelling evidence for invoking liquid unmixing as the main mechanism of their formation and evolution albeit few exceptions. We propose an evolutionary trend for the Brazilian carbonatites, which can be summarized as following: exsolution of the primary Ca- or Mg-carbonatitic liquids systematically takes place at the phonolite-peralkaline phonolite stage of magma differentiation; this is followed by progressive Fe-enrichment and by final emplacement of fluorocarbonatites associated with hydrothermal fluids.

中文翻译：

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来自巴西南部地台的碳酸岩：I

摘要 我们全面概述了巴西地台南部（巴拉那盆地）碳酸盐岩的地球化学特征和演化。来自不同复合物的碳酸岩在不相容元素和稀土元素的丰度方面表现出很大的成分变异性。这与同位素数据证实的来自非均质岩石圈源的起源一致（见 Speziale 等人，本期）。这些碳酸岩的特征性主要和微量元素丰度为将液体不混合作为其形成和演化的主要机制提供了令人信服的证据，尽管很少有例外。我们提出了巴西碳酸盐岩的演化趋势，总结如下：原生Ca-或Mg-碳酸岩液体的出溶系统地发生在岩浆分异的响岩-过碱性响岩阶段；随后是逐渐富集铁和与热液流体相关的氟碳酸盐的最终侵位。