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Plagioclase of Intrusive Rocks from the Pervomai–Ayudag Island-Arc Complex (Mountainous Crimea): from Plagiolherzolite to Plagiograniteстатья
Информация о цитировании статьи получена из
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Статья опубликована в журнале из перечня ВАК
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 13 ноября 2024 г.
- Авторы: Ovsyannikov G.N., Spiridonov E.M., Filimonov S.V.
- Журнал: Moscow University Geology Bulletin
- Том: 79
- Номер: 3
- Год издания: 2024
- Издательство: Allerton Press Inc.
- Местоположение издательства: United States
- Первая страница: 431
- Последняя страница: 443
- DOI: 10.3103/s0145875224700418
- Аннотация: The Middle Jurassic hypabyssal island-arc Pervomai–Ayudag intrusive complex in Mesozoic rocks of the Mountainous Crimea includes plagiolherzolite, olivine gabbronorite-dolerite, quartz and quartz-free gabbronorite-dolerite, quartz and quartz-free gabbronorite-diorite, quartz diorite, and plagiogranite. These rocks, except for quartz diorite and plagiogranite, have an abundance of anorthite (An92–90) and bytownite (An89–73). Such a composition of plagioclase is typical of island-arc mafic rocks. Due to the abundance of anorthite and bytownite depleted in silica, many types of gabbroids in the complex are quartz rich. Anorthite and bytownite are enriched in FeO (up to 0.9–1.0 wt %). The K2O content increases exponentially from anorthite to albite–oligoclase (from 0.0n to 1.4 wt %). The potassium content of plagioclase decreases noticeably even at a small degree of epigenetic metamorphic alterations. The elongation of plagioclase crystals in gabbro of the middle parts of the intrusions (from anorthite to andesine) is from 2 to 5.5, usually 3–4. Effusive-like porphyritic microgabbro-dolerite of the quenching zone contains plagioclase phenocrysts with an elongation of up to 10; split laths of plagioclase with an elongation of up to 10 or more occur in their fine-grained matrix.
- Добавил в систему: Филимонов Сергей Владимирович