Abstract

Lulak Abad iron occurrence is located in northwestern part of the Central Iran, 55 km west of Zanjan. In this area, iron mineralization occurs as veins, veinlets and lens-shaped bodies in deformed schist and metavolvanic units (equal to Kahar Formation) and granite. Based on microscopic studies, ore minerals are oligist ± magnetite and pyrite, and quartz, calcite and chlorite are present as gangue minerals at Lulak Abad. The ore minerals show disseminated, vein-veinlet, breccia and open space filling textures. Alteration is restricted to the silicified, calcitic and chloritic altered parts of the ore zones. Two stages of mineralization can be distinguished at Lulak Abad iron occurrence. Stage-1 is recognized as stratiform and stratabound lenses, laminated and disseminated crystals of magnetite in volcano-sedimentary host rocks. Stage-2 mineralization is characterized as oligist-pyrite-calcite veins and veinlets cutting the mylonitic foliation of the host rocks. Rare Earth Element (REE) pattern of nonmineralized host rocks and the mineralized samples indicate that mineralized samples are depleted in Light REE (LREE) and enriched in Heavy REE (HREE). These signatures indicate high W/R interaction in Lulak Abad. Comparison of the geological, mineralogical, geochemical, textural and structural characteristics of the Lulak Abad occurrence with different types of iron deposits reveals that iron mineralization at Lulak Abad is originally formed as volcano-sedimentary, and then reconcentrated as vein mineralization.