Petrography and geochemistry of Ebrahim- Abad iron ore deposit (northwest Divandere, Kurdistan Province)

Abstract

The Ebrahim-Abad iron deposit, consisting of Paleozoic metamorphic rocks, Mesozoic plutonic bodies and metasomatic rocks, occurred in the northwest of Divandere and the Sanandaj- Sirjan structural zone.The metamorphic rocks including micaschist and marble are cut by plutonic intrusive rocks (granodiorite to milonitic and cataclastic granite). Mica schist and associated detrital sediments have been changed in the low- grade greenschist facies. Marbles and plutonic rocks have also undergone cataclastic metamorphism along shear zones. Metasomatic rocks are garnet- amphibolite to garnititic skarn composition crosscutting by magnetic veins. Iron mineralization as magnetite, chiefly occurred as lenses, veins and veinlets as well as dissimented grains. Massive, dissiminated, replacement, and network textures are the main textures of this deposit. Magnetite developed as amorphous, fine (less than 1 mm), or dissiminated. Chlorite, trermolite- actinolite, epidote, garnet, and quartz with minor clay minerals and calcite are the gangue minerals of the studied ore deposit. Iron oxide grade varies from 14 to 47 FeO%. Fe shows a negative correlation with S, and Si, Al, Mg, Mn, Ca, K oxides but positive correlation with Cr and Co. Ti/Ni+Cr and Ni/Cr diagrams point to the hydrothermal origin of the iron ore under study. The variations in the cobalt, nickel, vanadium, and titanium contents indicate that the skarn- hydrothermal origin of the Ebrahim- Abad iron deposit. It seems that the iron oxide remobilized by hot hydrothermal fluids originated from intrusive bodies and redeposited in marble, mica schist, greenschist, and skarn.

Keywords

• fe-mineralization
• geochemistry
• hydrothermal
• skarn
• ebrahim-abad
• kurdistan