Petrography and mineral chemistry of layered pegmatite-aplite dykes from east of Boroujerd

Pegmatite-aplite dykes from north east of Lorestan Province is located about 25 km east of Boroujerd city and consists of three major zones, from outside to inside including graphic, layered and core zone that obviously shows the effect of fractional crystallization in pegmatites. Microprobe analysis performed on minerals (tourmaline, plagioclase and muscovite) from each three zones. Tourmalines from marginal zone have schorlite to foitite composition and tourmalines from layered zone have foitite composition that both of them lie in magmatic tourmalines category. These tourmalines plotted on FeO/FeO+MgO vs. MgO diagram have Fe# between 0.8 to 1 indicate that  they formed in magmatic conditions and external hydrothermal fluids did not effect  in formation of Tourmalins. Compositions of analyzed plagioclases from all three zones are rich in albite and the average compositions are; marginal zone (Ab98.05), layerd zone (Ab98.78) and core zone (Ab98.43), indicating a high degree of fractionation in source magma.