Тип публикации: статья из журнала

Год издания: 2025

Идентификатор DOI: 10.2113/rgg20244784

Аннотация: <jats:title>Abstract</jats:title> <jats:p>The Bilibin massif is a Mesozoic intrusion located in the southeastern part of the Aldan high-potassium igneous province of the Aldan–Stanovoy Shield of the Siberian Platform. This massif consists of the alkaline–mafic–ultramafic and granite–syenite phases, which form a concentric structureПоказать полностьюwith the rocks becoming more silica-rich from periphery to center. Earlier studies proposed that these phases formed either from different parental magmas or from a common lamproitic magma via magmatic differentiation. In this study, we examined a representative set of rock samples from the Bilibin massif: phlogopite clinopyroxenites, melashonkinites, shonkinites, alkali syenites, quartz syenites, and granites. Mineralogical–petrographic, geochemical, and isotope–geochemical data imply that the series of differentiation of lamproitic magma comprises rocks from clinopyroxenites to shonkinites and possibly alkali syenites, which form the first phase. The quartz syenites and granites, which form the second phase, belong to a separate magmatic series. According to geochemical data and the Nd, Sr, and O isotope composition of the quartz syenites and granites, the magmas which formed the syenites and granites were derived from the lower crust rather than from the lithospheric mantle and originated owing to either crustal melting during mantle-derived magmatism or collisional tectonics at the southern margin of the Siberian Platform in the Mesozoic Era. Rocks of the lamproite series allow us to consider it as an example of complete differentiation of a mantle lamproitic melt, with the following stages of cotectic crystallization: olivine + chromite, olivine + clinopyroxene + chromite, olivine + clinopyroxene + phlogopite, clinopyroxene + phlogopite + leucite, and clinopyroxene + phlogopite + K-feldspar. Spot analyses of trace elements in clinopyroxene, phlogopite, leucite, and apatite allow estimation of the melt–mineral partition coefficients in such a system.</jats:p>

Журнал: Russian Geology and Geophysics

Выпуск журнала: Т.66, №4

Номера страниц: 424-449

ISSN журнала: 10687971

Место издания: Novosibirsk

Издатель: Институт геологии и минералогии им. В.С. Соболева СО РАН, Институт нефтегазовой геологии и геофизики им. А.А. Трофимука СО РАН, Новосибирский национальный исследовательский государственный университет, Siberian Branch of Russian Academy of Sciences

• Chayka I.F. (2 Institute of Experimental Mineralogy, Russian Academy of Sciences, ul. Akademika Osip’yana 4, Chernogolovka, 142432, Russia)
• Izokh A.E. (3 Novosibirsk State University, ul. Pirogova 1, Novosibirsk, 630090, Russia)
• Sotnikova I.A. (4 Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, ul. Favorskogo 1a, Irkutsk, 664033, Russia)
• Alymova N.V. (4 Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, ul. Favorskogo 1a, Irkutsk, 664033, Russia)
• Kolotilina T.B. (4 Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, ul. Favorskogo 1a, Irkutsk, 664033, Russia)
• Karimov A.A. (5 Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences, ul. Lermontova 128, Irkutsk, 664033, Russia)
• Shcherbakov V.D. (6 Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119234, Russia)
• Lobastov B.M. (7 Siberian Federal University, pr. Imeni Gazety Krasnoyarskii Rabochii 95, Krasnoyarsk, 660025, Russia)

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