Petrogenesis of Yolcular metamorphite (Bitlis-Hizan) and aplit dykes

In the study area, the Yastıktaş gneiss of the Bitlis massif is represented by the Karakuş amphibolite and the Doğruyol gneiss. Yastıktaş eyed-gneiss with gneiss, Karakuş amphibolite with amphibolite and Doğruyol gneiss are composed of quartzo-feldspathic gneiss. . These leucogranitic rocks were deposited as masses compatible with amphibolite and granitic gneisses and mostly unconformable. When the stratigraphy of the rocks belonging to the Yolcular metamorphite is examined, it is seen that they are composed of amphibolite, micagneiss/schist and rocks such as granitic augen gneiss, quartzo-feldspathic gneiss, biotite metagranite and melapegmatite cutting these units. The vein rocks indicating acidic magmatic activity were formed as a result of the separation of the Arabian plate from the Anatolian plate by rifting in the Upper Triassic. During this period when magmatic activity started, orthogneisses with Pan-African magmatism and then leucocratic paragneisses in Triassic were formed. The second main magmatic activity in the Metamorphic Massif caused the formation of aplites. Bitlis Metamorphite Yolcular group has been cut by aplite dykes in places and weathering due to magmatic activities and tectonic movements has caused the formation of retrograde cataclastic metamorphism traces in the rocks of the unit. The mineral compositions of the aplite samples belonging to the Bitlis metamorphite are alkaline feldspar, plagioclase, quartz, biotite and hornblende. Petrographic and geochemical analysis results indicate that aplites developed by magmatic differentiation from granite with the effect of second active magmatism. Granitic magma with tholeiitic and calc-alkaline composition underwent fractional crystallization and aplites were emplaced in the form of sills. The origin of the alumino-cafemic specimens is probably a hybrid magma, and the contribution of sialic origin to the formation of magma is high.