Mineralogical and Geochemical investigations of Celestite and Gypsum from GanjoTakkar area, Hyderabad, Sindh, Pakistan

Abstract

The mineralogical and geochemical studies on the celestite and gypsum deposits at the GanjoTakkar area of Hyderabad, Sindh, Pakistanin the stratigraphic horizons of Meting Shale and Laki Limestone belonging to the LakiFormation of the Eocene (Ypresian) ageare conducted to decipher their mode of formation. A total of 07 samples were collected during fieldworks and were later on processed for the major element concentration using XRF and for the mineral compositions using the XRD techniques. The Gypsum varieties found in the study area are the Fibrous and the Rose Gypsum. The Celestite in the study area is massive and a bit fibrous. The studies revealed that the solution/sea water from which the Celestite and Gypsum are formed through evaporation and as anhydrite experienced the extreme arid conditions at the time of the formation of these deposits. The mineral assemblages determined through the XRD are of three types: (a) Gypsum, Quartz low, Calcite (b) Calcite, Ankerite,Gypsum, and (c) Ankerite, Dolomite, Calcite. In these assemblages the enrichment of Quartz low is probably not the syngenetic. Meanwhile, the presence of Ankerite supports the idea of prevalence of extreme arid climate because it bears Fe++(Bivalent Iron) which is indicative of anoxic conditions.