Research Projects

Strontium (Sr) is an alkaline earth element that has four naturally occurring isotopes (84Sr, 86Sr, 87Sr, 88Sr). During measurements of 87Sr/86Sr, which is a powerful tracer of diverse Earth processes, the raw 87Sr/86Sr data is corrected for instrumental mass dependent fractionation assuming the 86Sr/88Sr ratio as a constant (0.1194). However, several studies have now shown that 86Sr/88Sr is not a constant in natural samples. Heterogeneity in 88/86Sr has been reported in meteorites and their components as well as in magmatic rocks and the heterogeneity in some mantle-derived rocks reflect crust-mantle interaction as well as hydrothermal processes. Variations in δ88/86Sr values have also been observed in products of low temperature processes from cold-water corals and coccolithophores where δ88/86Sr variability reflects water temperature to diagenesis, water mass mixing, etc. The present proposal aims to investigate Sr stable isotopic fractionation during low-temperature processes on Earth. Specifically, we’ll investigate: (i) Sr stable isotopic variability in rivers and groundwater, (ii) Sr stable isotopic fractionation during silicate weathering, (iii) Sr stable isotopic composition of biogenic and non-skeletal carbonates and (iv) efficacy of Sr stable isotopes as tracers of crustal recycling by investigating the Sr stable isotopic composition of carbonatites. The results of this study, based on combined measurements of stable and radiogenic Sr isotopes, will have important implications for Sr cycling on the Earth’s surface as well as between the crust and the mantle.