Plagioclase of Intrusive Rocks from the Pervomai–Ayudag Island-Arc Complex (Mountainous Crimea): from Plagiolherzolite to Plagiogranite
Journal: Moscow University Geology Bulletin
Year: 2024

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.