Sedimentology of a Recent Alluvial Fan of Ganga River, Rishikesh, India

Abstract The annual flow of the river Ganga is 468.7 billion cubic meters. The river emerges on the plain at Rishikesh from the mountains. The Alluvial fan deposits are divided into three facies: proximal, medial and distal fan facies. The nature of sediments varies from coarse gravel and boulders to fine gravel to coarse sand. The proximal facies show massive units (Gms) and coarsening upward of sediments. The gravel and boulders of proximal facies are randomly oriented and are poorly sorted, which are described as debris deposits. The sediments of mid fan facies show massive units (Gms), horizontal stratification (Gh) and planar cross-stratification (Gp). The sediments are moderately sorted and show imbrication. Distal fan Sediments are well sorted marked with trough cross-stratification (St) and gravelly channel deposits (Gs). The sediments of mid fan and distal fan facies show fining upward sequence and are described as water-laid deposits. The distal fan deposits show transitional relationship with the braided river deposits.