THE ISLAND ARC FERROCORDIERITE-ALMANDINE PLAGIORHYOLITES OF THE MOUNT KASTEL, MOUNTAIN CRIMEA

Abstract

Plagio rhyolites of the Pre-Late Jurassic dyke contain restitegamet (cribrate inter grow ths of almandinespessartine and quartz) and ferrocordierite. The garnets of such habit and composition and with such kind of zonality - the content of Mg increases and the content of Mn decreases from the center to the edges - are typical for ferriferous metapelites of amphibotite facies. Composition of the rocks, during palingenesis of which the melt of plagiorhyolites of the Mount Kastel formed, probably corresponded to the cordierite-almandine plagiogneisses. An assessment of the parameters of these metamorphic rocks forming according garnet and cordierite compositions is »550° С and 4 kbar, so they are metamorphic rocks of the amphibotite facies of moderate pressure. There is an assumption, that Mountain Crime a tectonic zone was possibly formed on the ancient crystalline basement, on the mature continental crust, possible continuation of the structures of Russian Plattorm to the south. Ferro cordierite - sekaninaite has been described in Crimea for the first time. A part of garnet and cordiertte was replaced by highly ferriferous chlorite (daphnite) and pumpellyite-(Fe), a part of biotite, titanomagnetite and ilmenite - by chlorite, epidote, pumpellyite-(Fe) and mineral with intermediate compotition between titantte and vuagnatite. The reby, plagio rhyoltes were subj ected by metamorphism of prehnite-pumpellyite facies.

Keywords

• реститовые альмандин и феррокордиерит
• хлорит
• дафнит
• пумпеллиит-(fе)
• титанит
• вюяньятит
• палингенез
• фундамент складчатой области горного крыма