Mineralogy, Petrography and Genesis of Jajarm Bauxite Deposit


The studied deposit is the main bauxite ore deposit in Iran, which is now being exploited. Main horizons of the Jajarm bauxite deposit, which has been developed on the karst topography of the Elika formation, are composed of diaspore, silica, iron and titanium oxides. This deposit indicates marine regression and domination of the equatorial continental climate in this time. The most important textures in the hard bauxite horizon are micritic, pseudo-porphyric, oolitic, pisolitic and micro-clastic. Major diagenetic features are pisolite, oolites and some diasporic cement in microfractures. Some epi-genetic processes such as deferrification and re-silicification have subsequently altered bauxiute ores. In many samples, presence of eroded and rounded intra-clasts is indication of reworking. Seemingly, under warm climatic conditions, do-minated in the early late Triassic time, weathering products of melaphyers (the early bauxite), after short-distance transportation, trapped in the karst topography on the Elika formation. Finally, bauxite-ization processes had completed in these karst features, which were under active circulation.