Petrology and petrography of quaternary volcanic rocks of north-northeastern Varzaghan (eastern Azarbaijan)

The studied area is located in the north-northeastern of Varzaghan in Eastern-Azarbaijan province, and from the structural point of view in Alborz-Azarbaijan Zone. In this area the Quaternary volcanic rocks are extended over the Pliocene units. The volcanic rocks under study are basalt,trachybasalt, trachyandesite and basaltic trachyandesite. These rocks have porphyritic texture with microlitic matrix and their main minerals consist of pyroxene and plagioclase. On the basis of geochemistry studies the volcanic rocks in this area have alkaline nature with sodic tendency and are enriched in light rare earth elements (LREE) and depleted in heavyrare earth elements (HREE). Petrographic and geochemistry evidences show the effect of mantle partial melting,fractional crystallization, contamination and continental crustal anatexy phenomena in formation of volcanic rocks. According to geotectonic diagrams these volcanic rocks belong to intercontinental basalts.