E. B. Salnikova, A. V. Stepanova, P. Ya. Azimov, M. A. Sukhanova, A. B. Kotov, S. V. Egorova, Yu. V. Plotkina, E. V. Tolmacheva, A. V. Kervinen, N. V. Rodionov, V. S. Stepanov
{"title":"А History of Coronitic Metagabbronorites in the Belomorian Province, Fennoscandian Shield: U-Pb (CA-ID-TIMS) Dating of Zircon–Baddeleyite Aggregates","authors":"E. B. Salnikova, A. V. Stepanova, P. Ya. Azimov, M. A. Sukhanova, A. B. Kotov, S. V. Egorova, Yu. V. Plotkina, E. V. Tolmacheva, A. V. Kervinen, N. V. Rodionov, V. S. Stepanov","doi":"10.1134/S0869591122060066","DOIUrl":null,"url":null,"abstract":"<div><p>The estimation of crystallization and metamorphic reworking ages of mafic rocks in the polycyclic Precambrian areas is a difficult problem. Magmatic baddeleyite can be partially or completely replaced by polycrystalline zircon within a wide range of temperature and pressures, from greenschist to granulite facies. Evaluation of the age of each phase of the zircon–baddeleyite aggregates can provide information on both the age of the magmatic crystallization and metamorphism. U-Th-Pb (SHRIMP-II) and U-Pb (ID-TIMS) geochronological studies were carried out for single baddeleyite grains and zircon–baddeleyite aggregates from gabbronorites (“drusites”) of the Ambarnsky massif (Belomorian Province, Fennoscandian Shield). The petrological studies indicate the simultaneous growth of coronas at the olivine–plagioclase boundary and zircon rims around baddeleyite. U-Pb (ID-TIMS) dating of single baddeleyite grains yielded 2411 ± 6 Ma crystallization age of gabbronorites of the Ambarnsky massif. U-Pb (ID-TIMS) dating coupled with the discrete chemical abrasion give an age of 1911 ± 35 Ma for metamorphic zircon rims. The obtained results indicate that coronitic textures in the gabbronorites were formed 500 million years later than the magmatic crystallization of rocks as a result of the granulite-facies metamorphism that was probably related to the Lapland-Kola orogeny.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.0000,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Petrology","FirstCategoryId":"89","ListUrlMain":"https://link.springer.com/article/10.1134/S0869591122060066","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 2
Abstract
The estimation of crystallization and metamorphic reworking ages of mafic rocks in the polycyclic Precambrian areas is a difficult problem. Magmatic baddeleyite can be partially or completely replaced by polycrystalline zircon within a wide range of temperature and pressures, from greenschist to granulite facies. Evaluation of the age of each phase of the zircon–baddeleyite aggregates can provide information on both the age of the magmatic crystallization and metamorphism. U-Th-Pb (SHRIMP-II) and U-Pb (ID-TIMS) geochronological studies were carried out for single baddeleyite grains and zircon–baddeleyite aggregates from gabbronorites (“drusites”) of the Ambarnsky massif (Belomorian Province, Fennoscandian Shield). The petrological studies indicate the simultaneous growth of coronas at the olivine–plagioclase boundary and zircon rims around baddeleyite. U-Pb (ID-TIMS) dating of single baddeleyite grains yielded 2411 ± 6 Ma crystallization age of gabbronorites of the Ambarnsky massif. U-Pb (ID-TIMS) dating coupled with the discrete chemical abrasion give an age of 1911 ± 35 Ma for metamorphic zircon rims. The obtained results indicate that coronitic textures in the gabbronorites were formed 500 million years later than the magmatic crystallization of rocks as a result of the granulite-facies metamorphism that was probably related to the Lapland-Kola orogeny.
期刊介绍:
Petrology is a journal of magmatic, metamorphic, and experimental petrology, mineralogy, and geochemistry. The journal offers comprehensive information on all multidisciplinary aspects of theoretical, experimental, and applied petrology. By giving special consideration to studies on the petrography of different regions of the former Soviet Union, Petrology provides readers with a unique opportunity to refine their understanding of the geology of the vast territory of the Eurasian continent. The journal welcomes manuscripts from all countries in the English or Russian language.