Zinc isotopes reveal disparate enriched sources of contemporary lamprophyres in Eastern Dharwar Craton

0578537 - GLÚ 2024 RIV DE eng J - Journal Article
Li, J.-Q. - Chen, J.H. - Krmíček, Lukáš - Zeng, G. - Zhang, X.Y. - Murphy, D.T. - Dalton, H. - Pandey, A. - Chalapathi Rao, N. V.
Zinc isotopes reveal disparate enriched sources of contemporary lamprophyres in Eastern Dharwar Craton.
Contributions to Mineralogy and Petrology. Roč. 178, November (2023), č. článku 89. ISSN 0010-7999. E-ISSN 1432-0967
Institutional support: RVO:67985831
Keywords : Zinc isotopes * Recycled carbonates * Enriched source * Lamprophyres * Eastern Dharwar Craton
OECD category: Geology
Impact factor: 3.5, year: 2022
Method of publishing: Limited access
https://link.springer.com/article/10.1007/s00410-023-02073-1

Lamprophyres are mantle-derived rocks characterized by enrichment of incompatible elements and volatiles, however, the origin of their enriched sources remains enigmatic. Here we present zinc isotopic data for contemporary Mesoproterozoic (~ 1.1 Ga) lamprophyres from three localities of the Eastern Dharwar Craton. The Mudigubba and Kadiri lamprophyres with island-arc basalt (IAB)-like trace element features, such as positive Pb and negative Nb–Ta, Zr–Hf and Ti anomalies, have mid-ocean ridge basalt (MORB)-like δ⁶⁶Zn values ranging from + 0.22‰ to + 0.29‰. In contrast, the Udiripikonda lamprophyre shows higher-than-MORB δ⁶⁶Zn values of + 0.39‰ to + 0.48‰ and elemental features of intra-plate magmas with a lack of pronounced Nb–Ta-negative anomalies. Based on the covariations between Zn isotopes and trace element ratios, we infer that the Mudigubba and Kadiri lamprophyres with MORB-like Zn isotopes and high Ba/La, K/Nb and low Nb/La, Ce/Pb ratios are inherited from sub-continental lithospheric mantle metasomatized by fluids derived from a subducted slab. On the contrary, the higher-than-MORB Zn isotopic compositions, with low Ba/La, K/Nb and high Nb/La, Ce/Pb, K/U and Ba/Th ratios for the Udiripikonda lamprophyre are inferred to derive from lithospheric mantle enriched by carbonatitic melts or subducted carbonate-bearing sediments within the mantle transition zone. Hence, our study suggests that contemporary lamprophyres can be derived from disparate enriched mantle sources.
Permanent Link: https://hdl.handle.net/11104/0349232