Sapphire-bearing magmatic rocks trace the boundary between paleo-continents: A case study of Ilmenogorsky alkaline complex, Uralian collision zone of Russia

Sorokina, Elena S.; Botcharnikov, Roman E.; Kostitsyn, Yuri A.; Rösel, Delia; Häger, Tobias; Rassomakhin, M.A.; Кононкова, Н. Н.; Somsikova, A. V.; Berndt, Jasper; Ludwig, Thomas; Medvedeva, E. V.; Hofmeister, Wolfgang

doi:10.1016/j.gr.2021.01.001

Cited by 4 publications

(1 citation statement)

References 73 publications

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“…Deformation banding, cataclasis, and brecciation arose during the postmagmatic and metamorphic evolution of the IVC. Large-scale recrystallization of rocks and ores [20,27], as well as pegmatite and syenite formation [53], are associated with the postorogenic stage of the IVC and Buldym complexes formation and postcollisional extension (~250 Ma).…”

Section: Mineralmentioning

confidence: 99%

Carbonatite complexes of the South Urals: geochemical features, ore mineralization, and geodynamic settings

Nedosekova

2022

PMI

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The article presents the results of study of the Ilmeno-Vishnevogorsky and Buldym carbonatite complexes in the Urals. It has been established that the carbonatites of the Ilmeno-Vishnevogorsky complex are represented by high-temperature calciocarbonatites (sövites I and II) with pyrochlore ore mineralization. U-Ta-rich populations of uranium pyrochlores (I) and fluorocalciopyrochlores (II) crystallize in miaskite-pegmatites and sövites I; fluorocalciopyrochlores (III) and Sr-REE-pyrochlores (IV) of late populations form in sövites II. In the Buldym complex, along with high-temperature calciocarbonatites containing fluorocalciopyrochlore (III), medium-temperature varieties of magnesiocarbonatites with REE-Nb mineralization (monazite, niobo-aeschynite, columbite, etc.) are widespread. Miaskites and carbonatites of the Urals are characterized by high contents of LILE (Sr, Ba, K, Rb) and HFSE (Nb, Ta, Zr, Hf, Ti), which are close to the contents in rift-related carbonatite complexes of intraplate settings and significantly differ from synorogenic collisional carbonatite complexes. The Ural carbonatite complexes formed on continental rift margins during the opening of the Ural Ocean at the time of transition from extensional to compressional tectonics. Later on, they were captured and deformed in the suture zone as a result of collision. Plastic and brittle deformations, anatexis, recrystallization of rocks and ores of carbonatite complexes in the Urals are associated with orogenic and post-collision settings.

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Section: Mineralmentioning

confidence: 99%

Carbonatite complexes of the South Urals: geochemical features, ore mineralization, and geodynamic settings

Nedosekova

2022

PMI

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Trace Element Impact on the Corundum Morphology

Sorokina

2023

Springer Proceedings in Earth and Environmental Sciences

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Petrologically controlled oxygen isotopic classification of cogenetic magmatic and metamorphic sapphire from Quaternary volcanic fields in the Eifel, Germany

Schmidt,

Hertwig,

Cionoiu

et al. 2024

Contrib Mineral Petrol

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Gem sapphire is commonly retrieved from primary and secondary deposits associated with alkali basaltic fields, but its source rocks are rarely preserved. The Eifel (Rhenish Massif, western Germany), although not producing gem sapphire, shares many petrologic and geochemical similarities with such fields worldwide. Due to the young age of volcanic deposits and active quarrying, sapphire-bearing rocks are readily accessible, along with detrital sapphire from modern sediments. Here, oxygen isotope and trace element compositions are reported for 223 sapphire grains, and rutile and zircon inclusions in sapphire were dated indicating crystallization synchronous with Paleogene–Quaternary volcanism. Endmembers in δ18O range are sapphires from syenites representing mantle-derived differentiated melts with minor crustal contamination (~4–6‰) and contact metamorphic mica schists (>10‰) as purely crustal source rocks. Intermediate values between ~6 and 10‰ require variable degrees of mantle-crust hybridization. Lower crustal granulite sources are dismissed based on their oxygen isotopic compositions being lower than most sapphire crystals. Diffusion modelling of sharp oxygen isotopic zonation in compositionally zoned crystals precludes crystal residence at >900 °C over the lifetime of evolved magma reservoirs in the Eifel (c. 50 ka). This argues against direct mantle or lower crustal sapphire origins. Instead, low temperature residence is consistent with sharp δ18O gradients, coexisting andalusite, and fluid inclusion barometry. Hence, Eifel sapphire crystallization is attributed to contact metamorphic aureoles around upper crustal (5–7 km) magma bodies where phonolite, trachyte, and carbonatite melts differentiated from mafic parental magmas, and reacted with metasedimentary wall rocks.

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Sapphire-bearing magmatic rocks trace the boundary between paleo-continents: A case study of Ilmenogorsky alkaline complex, Uralian collision zone of Russia

Cited by 4 publications

References 73 publications

Carbonatite complexes of the South Urals: geochemical features, ore mineralization, and geodynamic settings

Carbonatite complexes of the South Urals: geochemical features, ore mineralization, and geodynamic settings

Trace Element Impact on the Corundum Morphology

Petrologically controlled oxygen isotopic classification of cogenetic magmatic and metamorphic sapphire from Quaternary volcanic fields in the Eifel, Germany

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