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<p>Volcanic rocks located within the northern Kandalaksha-Kolvitsa granulite belt represent a phase of post-collisional magmatism related to the final stage of the Paleoproterozoic evolution of the Lapland-Kola Orogen (LKO). This article presents a geological, petrographic, mineralogical, and geochemical study, as well as U–Pb dating of the volcanic rocks. These rocks form a lens-shaped body measuring 1500 × 150 − 400&#xa0;m, overlying a Paleoproterozoic intrusion of leucocratic metagabbro. The main rock-forming minerals of the volcanic rocks are represented by calcium amphiboles such as pargasite and ferropargasite (phenocrysts), magnesio-ferri-hornblende, ferro-hornblende, and magnesio-hornblende (groundmass), as well as plagioclase (labradorite and andesine). Geochemically, the volcanic rocks belong to the tholeiitic ferrous basalt-andesite series with SiO<sub>2</sub> contents ranging from 49 to 57 wt% and <i>Fe#</i> values (<i>Fe#</i> = 100 × FeO<sub>tot</sub>/(FeO<sub>tot</sub> + MgO)) of 62–78%. They are enriched in light rare earth elements, depleted in high-field strength elements, and exhibit positive anomalies of large-ion lithophile elements. Based on rare earth elements ratios, the parental magma of the volcanic rocks formed through decompression-induced partial (~ 5%) melting of mantle spinel lherzolites. The results indicate that the magmatic episode responsible for the formation of the volcanic rocks occurred at ~ 1.88&#xa0;Ga as a result of extension following the completion of continental collision and subduction in the LKO. This magmatic event marks the end of granulite metamorphism and deformation in the northeastern Fennoscandian Shield.</p> Graphical Abstract <p></p>

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Petrogenesis, SHRIMP U–Pb age, and tectonic implication of post-collisional volcanic rocks from the Kandalaksha-Kolvitsa granulite belt (Kola Region, NW Russia)

  • 期刊论文

  • 发表日期：

    2026年4月17日

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  • Victor V. Chashchin,
  • Sergey A. Sergeev,
  • Ekaterina N. Steshenko

摘要

Volcanic rocks located within the northern Kandalaksha-Kolvitsa granulite belt represent a phase of post-collisional magmatism related to the final stage of the Paleoproterozoic evolution of the Lapland-Kola Orogen (LKO). This article presents a geological, petrographic, mineralogical, and geochemical study, as well as U–Pb dating of the volcanic rocks. These rocks form a lens-shaped body measuring 1500 × 150 − 400 m, overlying a Paleoproterozoic intrusion of leucocratic metagabbro. The main rock-forming minerals of the volcanic rocks are represented by calcium amphiboles such as pargasite and ferropargasite (phenocrysts), magnesio-ferri-hornblende, ferro-hornblende, and magnesio-hornblende (groundmass), as well as plagioclase (labradorite and andesine). Geochemically, the volcanic rocks belong to the tholeiitic ferrous basalt-andesite series with SiO2 contents ranging from 49 to 57 wt% and Fe# values (Fe# = 100 × FeOtot/(FeOtot + MgO)) of 62–78%. They are enriched in light rare earth elements, depleted in high-field strength elements, and exhibit positive anomalies of large-ion lithophile elements. Based on rare earth elements ratios, the parental magma of the volcanic rocks formed through decompression-induced partial (~ 5%) melting of mantle spinel lherzolites. The results indicate that the magmatic episode responsible for the formation of the volcanic rocks occurred at ~ 1.88 Ga as a result of extension following the completion of continental collision and subduction in the LKO. This magmatic event marks the end of granulite metamorphism and deformation in the northeastern Fennoscandian Shield.

Graphical Abstract