Y Bayati-Rad; H Mirnejad; J Ghalamghash
Abstract
Gol-Gohar mining complex, located southwest of Sirjan (KermanProvince) and within the Sanandaj-Sirjan structural zone, has a number of iron-rich deposits that provides 30% of steel demand in the country. The main ore in this deposit is magnetite with subordinate amounts of hematite and accessory pyrite ...
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Gol-Gohar mining complex, located southwest of Sirjan (KermanProvince) and within the Sanandaj-Sirjan structural zone, has a number of iron-rich deposits that provides 30% of steel demand in the country. The main ore in this deposit is magnetite with subordinate amounts of hematite and accessory pyrite and chalcopyrite phases. Comparison of rare earth element (REE) distribution patterns of Gol-Gohar magnetite with those of magmatic magnetite (Kiruna) and also magnetite associated with granite and basalts show similar enrichment in light REE relative to the heavy REE and negative Eu anomaly. Such features can also be observed in apatite from Kiruna, Iron Spring, Choghar and Esfordi Fe ore deposits, the origin of all of which have been ascribed as magmatic due to a lack REE distribution patterns similar to phosphorites. Based on these characteristics, it seems that the magnetite in Gol-Gohar Fe deposit has dominantly originated from a magmatic fluid.
Y. Bayati Rad; H. Mirnejad; J. Ghalamghash
Abstract
Gol-Gohar iron mine in Sirjan with general tonnage of 1135 milion tons, is one of the most important iron sources in Iran. The main ore minerals in this ore deposit consist of magnetite and subordinate hematite. δ18O of magnetite ranges from 3.8‰ to 4.8‰, while the calculated δ18O ...
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Gol-Gohar iron mine in Sirjan with general tonnage of 1135 milion tons, is one of the most important iron sources in Iran. The main ore minerals in this ore deposit consist of magnetite and subordinate hematite. δ18O of magnetite ranges from 3.8‰ to 4.8‰, while the calculated δ18O of the fluids that are in isotopic equilibrium with magnetite, varies between 10‰ and 11.3‰. Such isotopic attributes indicates that magnetite originated from magmatic fluids that were also equilibrated with sources enriched in 18O. This theory completely corresponds with the breaciated environment of Gol-Gohar ore deposit and the presence of metamorphosed sedimentary and igneous rocks with high δ18O amounts. Magnetite in Gol-Gohar iron, particularly in lower levels, is associatd with sulfide phases, so that the amount of sulfur increases with depth. The main sulfide phase in Gol-Gohar ore is pyrite that occupies the spaces between the magnetite grains and occurs as narrow veinletss. The δ34S values of pyrite (23.46‰-25‰) are similar to those of seawater sulfate (~30‰) and evaporative sulfates (10-30‰) and thus suggest pyrite originated likely from such sources. Texture and pertogrephic studies also show that sulfides were deposited after the formation of magnetite ore in Gol-Gohar.
