Postisland-arc fayalite-containing plagiogranites of mt. Kastel within mountain Crimea Kimmerides

Abstract

The hypabissal intrusive of Mt. Kastel fayalite plagiogranites intruded in the center of the South Bank uplift within Crimean kimmerides. Plagiogranites crosscut and local metamorphose the complexly folded flysch mass of Tauride series T2-J1, the bodies of island-arc gabbroids of Early Bayos Pervomaysk-Aju-Dag complex and basalts bodies of Late Bayos Karadag complex. Judging by the pattern of partings and the contact conditions, the intrusive is relatively weakly tectonized. Kastel postisland-arc plagiogranites (72,02 wt% of SiO2; 4,57 wt% of Na2О; 1,26 wt% of K2O; Na2О/K2O = 3,6; 92,4% of ferruginosity; Th >> U) contain high ferriferous olivine — fayalite, eulite and annite, rich in accessory zircon, monazite and xenotime. During the crystallization differentiation of plagiogranites of Mt. Kastel there was an accumulation of Fe and Mn in olivine composition, Na and K in plagioclase composition, Mn in ilmenite composition, Hf in zircon composition and Th in monazite composition, a narrowing of zircon and xenotime solid solutions composition. Endemic fayalite plagiogranites could arise under the conditions of orogenic regime, which, apparently, should be distinguished in the history of Mountain Crimean mesozoids.