ژئوشيمي توده نفوذي آيركان، دايك هاي آپليتي و آنكلاوهاي موجود در آن (شمال شرق استان اصفهان)

Geochemistry of Ayrakan Intrusion, Aplitic Dike and Enclaves (NE of Isfahan Province)

The area of study is in the North of khur and North-East of Arusan-e-kur-e-Gaz, which in geology divisions is in Central Iran. In petrographic study intrusive body, aplitic dikes and enclaves are alkali granite. Minerals of alkali granites are K-feldspar (orthoclase and microcline), plagioclase (albite and oligoclase), quartz with undoluse straight extinction, biotite, muscovite, zircon and apatite. Chlorite is created by biotite alteration. Intrusive body has foliation in many parts that look like auegen gneiss in the first view. But investigations show that this intrusive mass is mylonitized. Geochemical investigation shows the nature of calc alkalin, peraluminous and S-type nature of understudy granitoids. Thus samples of studying area located in syncollision region. The temperature given by two feldspars thermometry, that is lower than temperature of igneous environment, present the sub-solidus changes of feldspars composition. Ti in biotite thermometry result 632-661°C for biotites of intrusive body, aplitic dikes and enclaves. The obtained temperatures reveal the igneous temperatures of biotite crystallization. In addition, chlorites of alkali granites display a temperature around 188°C. This temperature indicates the biotite alteration temperature.