Mukul Sharma Current Research Interests in Isotope Geochemistry

• Near surface geochemistry of osmium
• Generation of oceanic lithosphere: the role of mantle heterogeneities
• Magma Differentiation and Source Characteristics of Continental Flood Basalts
• Early evolution of the earth: the terrestrial record of 146Sm
• Study on continental weathering using osmium isotopes
• Variations in Solar Magnetic Activity and the Sun-Climate Connection
• Tracing the source of groundwater arsenic in Bangladesh Delta
• Geochemical and isotopic studies of cosmic dust
• Near surface geochemistry of osmium
• Osmium and Iridium Transport through Estuarine Environments

Variations in Solar Magnetic Activity and the Sun-Climate Connection

The production of 10Be in the Earth's atmosphere depends on the galactic cosmic ray influx that, in turn, is affected by the solar surface magnetic activity and the geomagnetic dipole strength. Using the estimated changes in 10Be production rate and the geomagnetic field intensity, We have calculated variations in solar activity for the last 200,000 years. Large variations in the solar activity are evident with the Sun experiencing periods of normal, enhanced and suppressed activity. The estimated variations in solar surface magnetic activity are also strongly correlated with the marine d18O record on a 100,000-year timescale. As the marine d18O record reflects changes in the amount of ice locked up on the Poles, We have proposed that variations in solar activity control the 100,000-year glacial-interglacial cycles of Ice Ages. If this hypothesis holds up to further scrutiny, this would open up new avenues of investigations into the Sun-Climate relations. At present, I am working to devise experiments that would prove or disprove this proposition.