Tomsk State University
Geology and geography faculty
RESEARCH, TEACHING, or OTHER INTERESTS
Geology, Geochemistry and Petrology
3
Scopus Publications
Scopus Publications
New Data on the Polychronic Early Paleozoic Alkaline Magmatism in the Tuva–Mongolian Massif of the Central Asian Orogeny Belt A. A. Petlina, V. V. Vrublevskii, M. V. Stifeeva, A. B. Kotov, E. B. Salnikova Doklady Earth Sciences, 2025 Abstract New data on the geology, geochemistry, and age of alkalinene magmatism in the Southwest Khovsgol region are reported. Based on the U–Pb (ID-TIMS) geochronological study of titanite from alkaline clinopyroxenite of the Shivleggol massif (part of the Beltesingol group of massifs), the age is estimated at 450 ± 1 Ma. This new age makes it possible to outline one more stage of polychronous Early Paleozoic alkaline magmatism within the Tuva–Mongolian massif.
He Isotopic Composition of Alkaline Intrusions of the Hovsgol Area, Northwestern Mongolia V. V. Vrublevskii, A. A. Petlina, A. V. Gudkov, M. Yu. Sidorov, A. S. Semiryuakov, R. A. Shelepaev, A. V. Vishnevskii, I. F. Gertner, E. N. Fomina, E. N. Kozlov, O. V. Udoratina Doklady Earth Sciences, 2023 The He isotopic composition of fluid inclusions in magnetite of alkaline and subalkaline intrusion of the Hovsgol region, Northwestern Mongolia, is studied. The measured 4He content varies from 6.6 × 10–7 to 114 × 10–7 cm3/g. The 3He/4He isotope ratio of most samples is 0.23–0.59 Ra indicating the presence of He from different sources in magmatic fluid. The maximum of mantle He (2.51 Ra) is observed in magnetite of subalkali gabbro. The mantle He component was ~40–60% during the generation of parental magma with possible involvement of subcontinental lithospheric mantle material or a plume-like reservoir less enriched in 3He. The mantle He component did not exceed 10–15% during the evolution of the foidoitic and alkali-syenitic melts because of mixing with crustal radiogenic He. We suggest the interaction of intrusions with fragments of the Precambrian accretionary–collision complexes of the Tuva–Mongolian Terrane. This mixing of He isotopes in melts and fluids can serve as indirect evidence of the development of mantle magmatism at the active continental margin.
