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Ice Cores PowerPoint Presentation

Ice Cores

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Ice Cores

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  1. Ice Cores • Very important paleoclimatic archives. • Records of past atmospheric conditions. • Temperature • Humidity • Snow accumulation • Atmospheric composition • Volcanic activity • Tropospheric turbidity • Wind speed, wind direction • Atmospheric circulation

  2. Ice Core drilling

  3. Stable Isotopes-Concepts • Name Symbol Definition • Atomic number Z # protons (p+) • Neutron number N # neutrons (n) • Mass number A # p+ + n

  4. Abundance of stable isotopes of water

  5. Physical properties of water

  6. Isotope effect and fractionation • Isotopes undergo the same chemical and physical reactions. • The rate of these reactions, however, could be different (isotope effect), resulting in the partitioning of isotopes (fractionation).

  7. Terminology d=1000(Rsample/Rstandard – 1) where R=heavy isotope/lighter isotope d18O= 1000(18Rsample/18Rstandard – 1) where 18R=18O/16O dD= 1000(2Rsample/2Rstandard – 1) where 2R=D/H Standard is V-SMOW (Vienna-Standard Meteoric Ocean Water). d18OV-SMOW = dDV-SMOW = 0‰

  8. Temperature Altitude Distance from the source Latitude IAEA (2001).  GNIP Maps and Animations.

  9. IAEA (2001).  GNIP Maps and Animations

  10. IAEA (2001).  GNIP Maps and Animations

  11. Fricke and O’Neil, 1999

  12. Edwards et al., 2004

  13. d-excess • Meteoric Water Line: dD=8*d18O+10 d-excess under “normal” conditions d= dD-8*d18O Increased relative humidity or lower sea-surface temperature (reduced evaporation rates) produces lower d-excess values.

  14. Dating Ice Cores • Radio-isotopes • Ice layers • Ice flow models • Reference horizons

  15. Volcanic markers provide additional time control

  16. Seasonal variations can be detected with microparticles and glacio-chemical data

  17. Antarctic Ice Cores

  18. Vostok Ice Core

  19. Epica Group, 2004

  20. Epica Group, 2004

  21. Epica Group, 2004

  22. Greenland

  23. MIS-4 MIS-1 MIS-3 MIS-5 Blunier and Brook, 2001, Science

  24. Colder/Drier? Warmer/Wetter?