The Vitória dike swarm – A key piece in the puzzle of low-Ti tholeiitic magmatism of the South Atlantic Magmatic Province


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Date

2026-02

Publication Type

Journal Article

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yes

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Abstract

During the Early Cretaceous, widespread tectono-magmatic activity along the South Atlantic Rift System led to the development of a complex system of sedimentary basins accompanied by basaltic, silicic, and alkaline magmatism. In the northern Mantiqueira Province (Espírito Santo, Brazil), the Vitória–Ecoporanga belt marks an intensely fractured/faulted NW–SE structural belt that hosts the Vitória dikes, representing the northernmost mafic dike swarm of the Paraná–Etendeka Magmatic Province (PEMP). The dikes are microgabbros composed of plagioclase, clinopyroxene, and Fesingle bondTi oxides, with MgO contents of 3.8–7.2 wt% and total alkalis of 2.4–4.8 wt%, consistent with subalkaline/tholeiitic basaltic compositions. They display enrichment in large-ion lithophile elements and pronounced negative Nbsingle bondTa anomalies relative to Rb, Ba, U, Th, K, La, Ce, and Pb. Isotopic compositions show variable 87Sr/86Sr(i) (0.70575–0.70994), εNd(i) (−11.4 to −0.95), and heterogeneous Pb isotopic ratios (206Pb/204Pb = 16.7–18.2; 207Pb/204Pb = 15.4–15.6; 208Pb/204Pb = 37.6–38.9). Ksingle bondAr and 40Ar/39Ar data constrain the emplacement to the Early Cretaceous. Comparative geochemical, isotopic, and geochronological data reveal strong affinities between the Vitória and Riacho do Cordeiro dikes of the Equatorial Atlantic Magmatic Province (EQUAMP). These similarities indicate that both systems share a common evolutionary history, representing remnants of a possibly interconnected low-Ti tholeiitic magma plumbing system active during the early stages of West Gondwana breakup. Comparable compositional affinities are also recognized in other low-Ti tholeiites across the PEMP and EQUAMP. Collectively, this transcontinental low-Ti tholeiitic event represents the earliest stage of the South Atlantic Magmatic Province (SAMP).

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published

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Journal / series

Volume

522-523

Pages / Article No.

108360

Publisher

Elsevier

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Subject

SAMP; Paraná-Etendeka; EQUAMP; Continental breakup; Early Cretaceous

Organisational unit

09656 - Chelle-Michou, Cyril / Chelle-Michou, Cyril check_circle

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