Возраст сиенитов палеопротерозойского дубравинского супрасубдукционного щелочно-карбонатитового комплекса Курского блока Сарматии

Ekaterina Kh.  Korish; Konstantin A. Savko; Nikolay S. Bazikov; Alexander N. Larionov

doi:10.17308/geology/1609-0691/2024/1/4-13

Ekaterina Kh. Korish Voronezh State University https://orcid.org/0000-0002-6573-1272
Konstantin A. Savko Voronezh State University https://orcid.org/0000-0002-7291-7024
Nikolay S. Bazikov Voronezh State University https://orcid.org/0000-0002-0847-6498
Alexander N. Larionov Centre for Isotope Research, Karpinsky Russian Geological Research Institute https://orcid.org/0000-0002-8418-2176

DOI: https://doi.org/10.17308/geology/1609-0691/2024/1/4-13

Keywords: Kursk block, geochronology, carbonatite

Abstract

Introduction: The paper is intended to reconsider the age of Dubravinsky alkali-carbonatite complex (Kursk block, Sarmatia) syenites according to the zircon and titanite U-Pb dating and Sm-Nd-Sr isotopic geochemical data in order to revise the geodynamical model of its forming.
Methodology: We carried out the isotopic dating of the Dubravinsky alkali-carbonatite complex syenites by zircon (SIMS) and titanite (ID TIMS), and also the Sm-Nd-Sr isotopic systematics.
Results and discussion: The age of zircon from syenites is ca. 2.59 Ga and previously was wrongly interpreted as the crystallization age. However, Sm-Nd-Sr isotopic data revealed this age being older than the age of syenites intrusion and so the zircon is captured. According to the titanite dating, the syenites crystallization age is 2.07–2.08 Ga, hence the geodynamical model of their forming needs to be revised.
Conclusion: Dubravinsky alkali-carbonatite complex aged 2.07–2.08 Ga has been formed in the suprasubductional environment.