رده بندی آمفیبول های کانسار سنگ آهن ناحیه سنگان خواف

oeeuring in the Sangan arca was fonned within two different rock groups· graitoids and skarns. Based on the new amphibole classification and nomenclature, the general fonnula of amphibols IS (AB2C,T,O"OH),. Amphibole of granitoids is a ferroedenite in which Si = 6.87 - 7.75, CaR> 1.5, (Na+K)A > 0.5 and Ti < 0.5. Skarn amphiboles are mostly developed within amphibole skarns and gamet-pyroxene skarns during retrograde stage of skarn evolution. High-temperature amphiboles are rich in Al while low-temperature amphiboles are poor in AI. Skarn amphiboles are classified in two groups: (a) hastingsite in which Si = 5.99 - 6.08, CaB> 1.5, (Na+K)A > 0.5, Ca < 0.5 and Al < Fe+] (b) ferroactinolite in which Si = 7.61 - 7.90, CaB>1.5, (Na+K)A < 0.5 and CaA < 0.5. Amphibole in (a) is AI-rich while amphibole in (b) is AI-poor.