Petrography and Geochemistry of the REE-bearing Fe-Oxide-Apatite Assemblages from the Sheytour Deposit East Central Iran

Azat Eslamizadeh¹ Shahram Samanirad²

1) Faculty member of Islamic Azad University, Bafgh Branch, Iran
2) Islamic Azad University, Bafgh Branch, Iran

Publication : International Conference On Research Science And Technology(restconf.org)
Abstract :
Sheytour deposit that is also known as Gazestan or Anomaly 5a, situated at the Bafq-Posht-e-Badam metallogenic belt in Central Iran. It is one of the Kiruna type magnetite- apatite ore deposits in this region. This deposit is host by the low metamorphic green rocks and calc-alkaline volcanic rocks that mainly consist of rhyolite, trachyte, and trachy-andesite. The diabasic dykes intersected these rocks. The Sheytour IOA deposit with a magmatic origin of iron-apatite has experienced multi stage mineralization as various forms including euhedral, vein type, and disseminated magnetite ore bodies. It has most likely formed by interaction of magmatic-hydrothermal processes. These agents were affected by moderately brine-dominated meteoric fluids, and metasomatic replacement. The intense alteration led to create the low- grade metamorphic green rocks that are often associated with iron-apatite mineralization. The apatite has a composition close to a pure fluorapatite with 2.69% F and 0.08% Cl on average. Investigation of REE distribution in the Sheytour deposit, indicated the apatite with monazite inclusion is rich of LREE (2.3% on average). Apatite has a distribution pattern as the same as magnetite, and poorly mineralized siliceous rocks. Besides of hydrothermal processes and the fluids associated with low metamorphic events that have increased or reduced the REE concentrations in the Fe-oxide –apatite assemblages, this similarity is most likely due to existence of monazite or other REE carrier minerals as individual crystals outside the apatite also in mixed with magnetite.
Keywords : Petrography geochemistry REE IOA deposit Sheytour