P-T PATHS OF COOLING AND METAMORPHISM IN THE LOW-GRADE AMPHIBOLITE FACIES CONDITIONS IN THE GRANULITES OF THE SIBERIAN CRATON

Grigorieva, V.M.; Perchuk, A.L.; Shatsky, V.S.; Zinovieva, N.G.

Авторы: Grigorieva V.M., Perchuk A.L., Shatsky V.S., Zinovieva N.G.
Журнал: Doklady Earth Sciences
Том: 514
Год издания: 2024
Издательство: Maik Nauka/Interperiodica Publishing
Местоположение издательства: Russian Federation
Первая страница: 84
Последняя страница: 91
DOI: 10.1134/S1028334X23602687
Аннотация: The results of detailed petrological studies of mafic granulites from the Yubileinaya (AlakitMarkha field) and Novinka (Upper–Muna field) kimberlite pipes, where retrograde metamorphic P–T pathswere reconstructed for the first time using mineral geothermobarometry, are provided. These P–T pathsdemonstrate subisobaric transition of the rocks from the P–T conditions of low-grade granulite facies to lowgrade amphibolite facies at the depth of the middle crust. It was found that the compositions of garnet, clinopyroxene, and orthopyroxene depend on the adjacent mineral, reflecting the different closure temperaturesof the exchange mineral reactions. The higher temperatures are determined using a two-pyroxene geothermometer, while the lower ones are found by application of garnet–clinopyroxene and garnet–orthopyroxenegeothermometers. Phase equilibria modeling showed the thermodynamic conditions of the low-gradeamphibolite facies: 540°C, 0.76 GPa, lgfO2 = QFM + 1.7 (Yubileinaya pipe); 530°C, 0.72 GPa, lgfO2 =QFM + 2.2 (Novinka pipe). The stability of the granulite paragenesis of garnet + clinopyroxene + orthopyroxene + plagioclase under such P–T conditions is a poorly known phenomenon reflecting a deficit of aqueous fluid during the crystallization of gabbroids and their subsequent cooling in the deep segments of cratons
Добавил в систему: Зиновьева Нина Георгиевна

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P-T PATHS OF COOLING AND METAMORPHISM IN THE LOW-GRADE AMPHIBOLITE FACIES CONDITIONS IN THE GRANULITES OF THE SIBERIAN CRATONстатья

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