Investigating the geochemical processes and origin responsible for Qopic bauxite deposit formation(west of Miandoab-west Azarbaijan)

Category Economic geology & mineral exploration
Group GSI.IR
Location 20th symposium on geosciences
Holding Date 16 April 2008

     The Qopi bauxite prospect is located in West Miandoab, West Azarbaidjan. Field investigations in the study area show that there is a stratigraphic gap between late Permian-Triassic period. This gap is represented by the presence of bauxitic horizon which is indicative of an intensive weathering processes resulting in Al, Fe, and Ti enrichment. Microscopic studies on thin and polished sections show ooidic , pisoidic, pelitomorphic, psuedo-porphyry, and fluidal textures as well as colloidal forms suggesting an authigenic deposition. Geochemical studies indicate that the underlying diabasic unit (30 m thick) acted as a potential source
rock for the deposit. The diabase was probably upheaved by tectonically imposed forces, and subjected to bauxitization.process. Considering an authigenic nature for the deposit and the diabase as the potential source rock, further geochemical method such as mass-change calculations was employed to better elucidate the geochemical processes responsible for the bauxite generation in the area. The result of these studies showed that Al and Ti were enriched and Si, Ca, Mn, Na, K, Mg, and P were depleted in the original rock material during bauxitization process. However, Fe concentration fluctuates within the bauxite deposit. Geochemical investigations and field evidence indicate that Qopi bauxite is of Mediterranean karst type, and lies within the range of argilloferruginous ferruginous bauxite facies.