The Carboniferous shoshonitic (s.l.) gabbro–monzonitic stocks of Veiros and Vale de Maceira, Ossa-Morena Zone (SW Iberian Massif): Evidence for diverse subduction-related lithospheric metasomatism

Amaral, João Lains; Mata, João; Santos, J. F.

doi:10.1016/j.chemer.2022.125917

Cited by 4 publications

(1 citation statement)

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“…Magmatic events in convergent plate margins preserve crucial information on the evolution of the mantle, continental accretion and amalgamation (Alizadeh et al, 2023; Babazadeh et al, 2022; Babazadeh, D'Antonio, Cottle, et al, 2021; Chen et al, 2020; Lains Amaral et al, 2022; Palin & Roberts, 2022). The Cadomian orogen developed during Late Neoproterozoic to Early Cambrian times, outbounding the supercontinent Gondwana during the Pan‐African collisional event.…”

Section: Introductionmentioning

confidence: 99%

Zircon U–Pb–Hf and whole‐rock Sr–Nd isotopic insights on the Silurian syenite–monzonite shoshonitic magmatism of Central Iran

Nayebi,

Raeisi,

Babazadeh

et al. 2023

Geological Journal

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The Palaeozoic magmatic history of Central Iran is related to the subduction of the Proto‐Tethys Ocean and the amalgamation of Gondwana continental fragments. This study presents whole‐rock geochemistry, Sr–Nd isotope and zircon U–Pb–Hf ages of shoshonitic plutonic rocks (e.g., monzonite–syenite) from the north Posht‐e‐Badam (NPB) district with a view to constrain their petrogenetic and tectono‐magmatic evolution during the Palaeozoic. The geochemical data show moderate enrichment in large‐ion lithophile elements and Ti, large positive Pb anomalies, and depletion or moderate enrichment in high‐field‐strength elements (e.g., Nb and Ta), typical of continental arcs. Zircon LA–ICP–MS U–Pb ages are in the range of 444–428 Ma. The Sr–Nd–Hf isotope data, for example, (87Sr/86Sr)i = 0.7073 to 0.7089, εNd(t) = −1.4 to −0.2, and εHf(t) = −3.6 to +7.7, indicate derivation of the magma from a mantle source. The numerical modelling shows a contribution of less than 10% crustal assimilation and ~3% sediment into the melt‐derived mantle. We propose that metasomatic enrichment occurred during the subduction of Proto‐Tethyan Ocean between the Iranian microcontinents, leading to the formation of a shoshonitic melt. We infer that the recorded ages coincide with a continental rift episode followed by a rear arc tectonic region that spread along the northern active margin of Gondwana. Further, the change in magma affinity from calc‐alkaline (~474–512 Ma) to shoshonitic (444–428 Ma) in Central Iran is probably related to the gradual steepening of the slab dip angle and trench‐ward migration of the front arc into the region above metasomatically enriched rear arc mantle.

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Section: Introductionmentioning

confidence: 99%

Zircon U–Pb–Hf and whole‐rock Sr–Nd isotopic insights on the Silurian syenite–monzonite shoshonitic magmatism of Central Iran

Nayebi,

Raeisi,

Babazadeh

et al. 2023

Geological Journal

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Contact metamorphism and dolomitization overprint on Cambrian carbonates from the Ossa-Morena Zone (SW Iberian Massif): implications to Sr-chronology of carbonate rocks

Roseiro,

Moreira,

Andrade

et al. 2024

Int J Earth Sci (Geol Rundsch)

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The Cambrian Series 2 Carbonate Formation from the Alter do Chão Elvas-Cumbres Mayores unit (Ossa-Morena Zone, SW Iberian Massif) is composed of regionally metamorphosed marbles and marlstones that underwent chlorite zone metamorphism and preserve the primaeval limestone 87Sr/86Sr ratios (0.7083–0.7088). These are consistent with the established Lower Cambrian seawater curve, and therefore used for age constraints in formations lacking fossil contents. The regional mineralogical and Sr-isotopic features of the carbonate rocks are frequently overprinted by the effects of contact metamorphism induced by magmatic bodies emplaced during rift-related and synorogenic events of the Palaeozoic, as well as by post-metamorphic dolomitization processes. The development of calc-silicate minerals due to contact metamorphism is common in the rocks of the Carbonate Formation and apparently results from the interaction of the protolith with fluids of different origin: (i) internally produced fluids released by conductive heating (observed in external contact aureoles) and (ii) external intrusion-expelled fluids that, besides leading to the appearance of distinctive assemblages, also promote an influx of strontium content (observed in roof pendants). Calc-silicate mineralogy varies substantially throughout the region, likely due to the heterogeneous distribution of silicate minerals of the protolith, progression of intrusion-driven fluids, and the irregular effect of thermal gradients. Results suggest that high-grade contact metamorphism (hornblende facies or higher) and dolomitization processes imposed on the Carbonate Formation significantly influence the isotopic signatures of the carbonates, providing limitations in applying Sr-isotopic chronology. Graphical abstract

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The bimodal Fii-A2-type and calc-alkaline volcanic sequence of the Aljustrel brownfield region, Iberian Pyrite Belt, SW Iberian Massif

Amaral,

Solá,

Bento dos Santos

et al. 2024

Geochemistry

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The Carboniferous shoshonitic (s.l.) gabbro–monzonitic stocks of Veiros and Vale de Maceira, Ossa-Morena Zone (SW Iberian Massif): Evidence for diverse subduction-related lithospheric metasomatism

Cited by 4 publications

References 151 publications

Zircon U–Pb–Hf and whole‐rock Sr–Nd isotopic insights on the Silurian syenite–monzonite shoshonitic magmatism of Central Iran

Zircon U–Pb–Hf and whole‐rock Sr–Nd isotopic insights on the Silurian syenite–monzonite shoshonitic magmatism of Central Iran

Contact metamorphism and dolomitization overprint on Cambrian carbonates from the Ossa-Morena Zone (SW Iberian Massif): implications to Sr-chronology of carbonate rocks

The bimodal Fii-A2-type and calc-alkaline volcanic sequence of the Aljustrel brownfield region, Iberian Pyrite Belt, SW Iberian Massif

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