Mineralogy, Geochemistry, and Origin of Nickel-Bearing Laterites in the Northwestern of Noorabad (Lorestan Province)

The nickel-bearing laterites of Noorabad area are seen in the high Zagros zone along with Kermanshah ophiolitic complex. The ophiolitic complex in the studied area includes serpentinized peridotites, isotropic gabbros, plagiogranite, sheeted dykes, basaltic lavas, andesite, and radiolarite. The peridotites of this ophiolitic complex include dunite, harzburgite, and lherzolite. The tectonic activities have caused tectonization in these rocks in such a way that it has facilitated their alteration process and created laterite zones. The alterations of peridotite rocks include serpentine, dolomite, hematite, and silicification. The laterite zone is layered and lens-shaped red horizon on peridotite rocks and is covered by Miocene limestones. Based on XRD analysis, mineralogy of the lateritic zone includes dolomite, quartz, smectite, and serpentine. The ratio of La/Y changes indicates that the studied laterites were formed in alkaline pH. According to the discrimination diagrams of the source rock, the studied laterites are karst bauxites with ultrabasic origin.