The strontium isotope ratios are examined in the shells of planktic foraminifer Orbulina universa in 20 samples from the late Miocene (8.03-6.36 Ma) sequence of Ocean Drilling Program (ODP) Site 758A, northeastern Indian Ocean. The Sr isotope ratios increased between 7.91 and 7.36 Ma and in the latest Miocene (6.48-6.36 Ma) reflecting high riverine flux from increased chemical weathering and high precipitation in the Himalayan region. The 87 Sr/ 86 Sr values decreased during 7.36 to 6.48 Ma coincident with the main phase of Chron-6 negative carbon shift. The carbon shift reflects high delivery of nutrients to the oceans. This contradicts the use of Sr isotope record as a strict proxy for global chemical weathering rates. The Sr isotope ratio should be used with great care in understanding the climatic- tectonic connections.