The use of quantitative data crystal size distributions (CSD) of pyroxenes crystals in study of petrological process of NE-Qorveh volcanic centers (Kurdistan)

Statistical measurements of crystal size distributions (CSD) are the new method for studying physical and petrological properties of igneous rocks. With emphasis on this method، the Plio-Quaternary lavas volcanic in the NE- Qorveh city are investigated. The lavas are basaltic in composition and there are pyroxenes with sieve texture، skeletal olivines، quartz with gulf corrosion and gneissic xenoliths. Quantity textures are studied in the CSD method. The rate of nucleation and growth timing of crystals are determined by pyroxene crystals size distributions. Timing of growth of pyroxene crystals between 17-36 years suggesting stability of crystallization conditions during eruption in the area. We used the logarithmic population density vs. crystal size diagrams with processing the software CSD correction. In the basaltic rocks of Qezelje-Kand village magmatic contamination occurred. In other volcanoes، such as the Qare-Bolaq volcano، residence time of magma was short.