The Early Cretaceous Paraná‐Etendeka Igneous Province is a predominantly tholeiitic sequence of continental flood basalts and silicic magmatism that is intimately associated with the rupture of the western Gondwana. Intrusions of tholeiitic compositions are very common within the province and represent the magmatic plumbing system that fed the lavas at the surface. The investigated dikes are in the southeast of the Paraná Basin, southermost Brazil. The Silica Saturated Olivine Tholeiite (SSOT) dikes show restricted isotopic ranges (⁸⁷Sr/⁸⁶Sr_i = 0.70570 to 0.70585; ɛNd_i = −1.01 to −4.49; ²⁰⁶Pb/²⁰⁴Pb = 18.031), with no equivalent low‐Ti magma type in the Paraná Province, but are close to the isotopic ratios of low‐Ti magma types with MgO > 7 wt%, such as Nil Desperandum in the Etendeka Province. The Silica Supersaturated Tholeiite dikes show broader isotopic ranges (⁸⁷Sr/⁸⁶Sr_i = 0.70787 to 0.71336; ɛNd_i = −2.51 to −8.65; ²⁰⁶Pb/²⁰⁴Pb = 18.578–19.049), similar to the Gramado magma‐type and Tafelberg magma‐type in the Paraná‐Etendeka Province. This variation may have occurred due to the contamination at the time of magma rise and extrusion. Isotopic modelling showed that the fractional crystallization process and crustal assimilation played an important role from the magma rise through the conduits to the extrusion of the lavas. For the most primitive SSOT dikes, fractional crystallization was the most important factor for the magma evolution. The behaviour of the trace elements revealed that the assimilation of crust rocks with both Palaeoproterozoic and Neoproterozoic ages can be considered.

中文翻译：

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巴西帕拉纳-埃滕德卡南部大火成岩省的基性岩浆岩侵入岩：地球化学和Sr-Nd-Pb同位素的见解

早白垩世巴拉那-埃滕德卡火成岩省是大陆洪水玄武岩和硅质岩浆作用的主要冲孔层序，与冈第瓦纳西部的破裂密切相关。在全省范围内，侵入性成分的侵入非常普遍，代表了岩浆管道系统，该系统将熔岩送入了地表。被调查的堤坝位于巴西最南端的巴拉那盆地的东南部。二氧化硅饱和橄榄石拉斑（SSOT）堤防表现出受限制的同位素范围（⁸⁷ SR / ⁸⁶锶_我= 0.70570到0.70585; ɛ钕_我= -1.01至-4.49; ²⁰⁶ PB / ²⁰⁴Pb = 18.031），在巴拉那州没有等效的低Ti岩浆类型，但接近MgO> 7 wt％的低Ti岩浆类型的同位素比率，例如Etendeka Province中的Nil Desperandum。二氧化硅过饱和拉斑堤防显示更广范围的同位素（⁸⁷ SR / ⁸⁶锶_我= 0.70787到0.71336; ɛ钕_我= -2.51至-8.65; ²⁰⁶ PB / ²⁰⁴Pb = 18.578–19.049），类似于Paraná-Etendeka省的Gramado岩浆类型和Tafelberg岩浆类型。这种变化可能是由于岩浆上升和挤压时的污染而发生的。同位素建模表明，从岩浆通过管道上升到熔岩挤出，分步结晶过程和地壳同化起着重要作用。对于最原始的SSOT堤防而言，分级结晶是岩浆演化的最重要因素。微量元素的行为表明，可以考虑地壳岩石同古元古代和新元古代的同化。