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SUMMARY:Strontium in the oceans: Where does it come from and where does it
  go? - Chris Pearce\, Open University
DTSTART:20111101T163000Z
DTEND:20111101T173000Z
UID:TALK32649@talks.cam.ac.uk
CONTACT:John Maclennan
DESCRIPTION:The radiogenic Sr isotope system is one of the most commonly u
 sed palaeo-weathering proxies. Variations in marine 87Sr/86Sr compositions
  provide an indication of the relative proportion of silicate material ver
 sus carbonate and basaltic material reaching the oceans as a consequence o
 f terrestrial weathering[1]. Despite many years of research\, however\, co
 ntroversy still exists over exactly what the dominant Sr fluxes are and th
 e timescales over which they may vary[2]. Recently the stable Sr isotope s
 ystem (δ88Sr) has also become established as a palaeo-proxy\, and has an 
 advantage over the radiogenic system in that δ88Sr fractionation also occ
 urs during incorporation into carbonates[3]. The sensitivity of the stable
  Sr isotope system to the dominant marine sink means a combination of 87Sr
 /86Sr and δ88Sr analyses may help resolve the persisting questions over S
 r mass balance in the oceans.\n\nIn this talk I shall present δ88Sr and 8
 7Sr/86Sr data from various marine inputs\, including dissolved and particu
 late riverine material (which account for >40 % of the global Sr flux to t
 he oceans)\, hydrothermal fluids\, glacial ice and rainwater. This data is
  compared to δ88Sr values from marine carbonates and the implications for
  the Sr isotopic evolution of seawater are discussed.\n\n[1] Palmer and Ed
 mond (1989). Earth Planet. Sci. Lett. 92\, 11-26.\n[2] Vance et al. (2009)
 . Nature 458\, 293-496.\n[3] Krabbenhöft et al. (2010). Geochim. Cosmochi
 m. Acta.74\, 4097-4109.\n
LOCATION:Harker 1 seminar room\, Department of Earth Sciences
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