Petrography and microtextural investigations of the deformed Siyahmansur granitoids from NE Miyaneh-East Azerbaijan province

The Siyahmansur area is located at southeastern end of the Bozgush mountain ranges in the Alborz-Azerbaijan zone. On the basis of field evidence, mineralogy and geochemistry the investigated granitoids can be classified as two types (a) Ms-granitoids, (b) alkali-granitoids. Outcropping of Ms-granite is limited to dykes and veins parallel to the metamorphic schistosity. Alkali-granitoid rocks are cropped out as a stock which is intruded in to the Cretaceous and Eocene sediments and volcanic rocks during Oligocene. Both granitoid types are deformed under strain tectonic condition and mylonite granitoids are formed in this regards. Ms-granites having peraluminous, A-type and anorogenic characteristics have been resulted from partial melting of metamorphic schists. Ms-granites recording extensive deformations are most probably emplaced under active tectonic conditions. Alkali-granitoid intrusion originated from mantle source are characterized as metaluminous and A-type granitoids. Concerning to the alkali-granitoids it seems they are emplaced due to faulting and fracturing related to decompression processes after closuring and collision of Neotethys during Alpine orogenic phase on Tertiary. On the basis of the recorded deformations on Siyahmansur alkali-granitoids it seems that they can be attributed to extrusion or escape tectonics in the intersections of southern Bozgush (Benarvan fault) and Germichai Faults.