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  • 2022

    2.52 MB, PDF document

  • Е.Б. Сальникова
  • А. В. Степанова
  • П.Я. Азимов
  • Мария Александровна Суханова
  • А.Б. Котов
  • С.В. Егорова
  • Юлия Плоткина
  • Елена Васильевна Толмачева
  • Анна Кервинен
  • Н.В. Родионов
  • В.С. Степанов
Timing of crystallization age and metamorphic reworking of mafic rocks from polycyclic Precambrian regions is a difficult problem. In a wide range of temperature and pressure (from greenschist to granulite facies) magmatic baddeleyite can be partially or completely replaced by zircon. As a result, aggregates composed by baddeleyite overgrown by polycrystalline zircon are formed. Evaluation of the age of each phase of the aggregates can provide information on both the age of the magmatic event and metamorphism. For the coronites of the Ambarnsky massif (Belomorian Province, Fennoscandia) U-Pb (ID-TIMS) geochronological investigations of zircon-baddeleyite aggregates have been performed. The petrological study of the rocks indicates the synchronous formation of coronas at the olivine–plagioclase border and zircon rims around baddeleyite. U-Pb (ID-TIMS) dating of single baddeleyite provide crystallization age of gabbronorites of the Ambarnsky massif at 2411 ± 6 Ma. Using of the “discrete chemical abrasion” the age at 1911 ± 35 Ma for metamorphic zircon rims is established. The obtained results demonstrate that the formation of corona structures resulted from granulite facies metamorphism during the Lapland-Kola orogeny and was separated from the crystallization time by 500 Ma.
Translated title of the contributionА HISTORY OF CORONITIC METAGABBRONORITES IN THE BELOMORIAN PROVINCE, FENNOSCANDIAN SHIELD: U-PB (CA-ID-TIMS) DATING OF OF ZIRCON-BADDELEYITE AGGREGATES
Original languageRussian
Pages (from-to)596-622
JournalПЕТРОЛОГИЯ
Volume30
Issue number6
StatePublished - 2022

    Research areas

  • U-pb zircon, BADDELEYITE GEOCHRONOLOGY, HIGH-TEMPERATURE ANNEALING, CHEMICAL ABRASION, metamorphism, CORONA STRUCTURES, Belomorian province

ID: 102562289