Ground Water Quality in Weathered Singhbhum Granite around Karanjia, Southern Bihar, India

Selected samples of well and spring waters from the weathered profiles of Singhbhum Granites show strong control of soil mineralogy. Felspars, mica, quartz and some mafic minerals in the bed rocks weather to kaolinite rich top soils in the cultivated lands. Soils at higher slopes are lateritic. Lime concretions are common and quartz is ubiquitous.

The HCO₃/SiO₂ mole ratio in the waters is in the range predicted for alteration of augite to kaolinite and plagioclase to montmorillonite. The silica level is above quartz solubility and generally below solubility of amorphous silica. Kaolinite and potassium are thermodynamically stable in ground water environment.