Radiogenic Osmium in Ganga river sediments of India.
Ganga river Sediments are the major source of radiogenic Osmium. by Dr. Nitish Priyadarshi The Ganga sediments are characterized by high Re/Os (rhenium-osmium) ratios and are extremely radiogenic as evident from their 187 Os/ 188 Os isotopic ratios. Samples from the tributaries Alaknanda, Bhagirathi, Gandak and Ghaghra show pronounced 187 Os/ 188 Os. High Os concentrations combined with sediments flux makes the Ganga an important source for soluble Os isotopic evolution in oceans. Interest in rhenium-osmium systematics in rivers has risen sharply in recent years due to the revelation of changes associated with sea water Os isotopic compositions during the past 70 Ma. Radiogenic 187 Os is produced from the β- decay of 187 Re. Osmium isotopic composition in sea water is derived from the weathering of basaltic and peridotitic oceanic crust, hydrothermal solutions, additions from cosmic dust and continental weathering products. Os isotopes in the oceans convey the then prevalent continenta...