Mineralogy, petrology of source rock and chemical condition of Abouzar Iron Skarn deposit, north-eastern Sabzevar

The Abouzar Iron skarn deposit is located 110 Km to north-west of Mashhad and 10 Km north-east of Shotorsang village. The calcic-iron skarn formed in Lower Cretaceous limestone. The Exoskarn zones are: garnet skarn, garnet-idocrase skarn, plagioclase skarn, actinolite skarn, zoisite skarn and zoisite-epidote skarn. Granite, granodiorite porphyry, quartz monzonite porphyry, syenodiorite and syenite porphyry are identified. Syenite and syenodiorite are alkaline and granite-granodiorite and quartz monzonite are sub-alkaline. All of the intrusive are met-aluminous only quartz monzonite is per-aluminous. Syenite porphyry is ultra potassium, syenodiorite is high potassium and granitegranodiorite and quartz monzonite is low in potassium. Syenite porphyry has high potassium but other are enrich in sodium. The pattern of spider diagram is quite different among the intrusive, indicating that the source of the magma must be different. In comparison with MORB basalt, the pattern of spider diagram show enrichment of K, Rb, Zr, Ba and Y and depletion of P, Ti and Sr. Based on mineral paragnesis, andradite was formed during prograde metamorphism (550°C). During retrograde metamorphism (