Chemical weathering of biotite in the Ganga Alluvial Plain

The present study describes the chemical weathering of biotite grains of the Gomati River sediments and release of various elements in dissolved load. Study argues that physical weathering in the Himalayan region is prominent, releasing huge amounts of sediment load to the Ganga River, with limited chemical weathering. Silicon concentration in the dissolved load of the Ganga River (100 mu mol/l) at Rishikesh is less than that of the Gomati River (700 mu mol/l) at Chandwak. On the other hand, chemical weathering of the Ganga Alluvial Plain is significant, primarily due to high content of porous, mica-rich silty sediments, which are flushed by the monsoon rain, transferring the elements as dissolved load of the alluvial rivers into the Ganga River system. These are the preliminary results of this study on chemical weathering in the Gomati River Basin