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OLLI WEST: EARTH CLIMATE – WEEK 3

OLLI WEST: EARTH CLIMATE – WEEK 3. FIELD TRIP: NATIONAL ICE CORE LAB Tuesday September 30, 2014. Paul E. Belanger, Ph.D. OLLI WEST: EARTH CLIMATE – WEEK 3. FIELD TRIP: NATIONAL ICE CORE LAB Tuesday September 30, 2014. SPECIAL THANKS TO OUR HOST(s):

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OLLI WEST: EARTH CLIMATE – WEEK 3

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  1. OLLI WEST: EARTH CLIMATE – WEEK 3 FIELD TRIP: NATIONAL ICE CORE LAB Tuesday September 30, 2014 Paul E. Belanger, Ph.D.

  2. OLLI WEST: EARTH CLIMATE – WEEK 3 FIELD TRIP: NATIONAL ICE CORE LAB Tuesday September 30, 2014 SPECIAL THANKS TO OUR HOST(s): • Richard Nunn and other personnel in the Ice Core Lab

  3. Western Interior Paleontological Society DATA

  4. EMPIRICAL DATA ACTUAL MEASUREMENTS: ATMOSPHERIC COMPOSITION, STABLE ISOTOPES, % CO3, ASSEMBLAGE INFORMATION, ETC.

  5. EMPIRICAL DATA • SOME OF THIS DATA YOU CAN’T DO MUCH WITH • ONE NEEDS TO INTERPRET WHAT IT MEANS THAT THEN MAKES IT “PROXY” DATA

  6. “PROXY” DATA DATA BY WHICH WE MAKE INTERPRETATIONS

  7. EARLY PROXY DATA: TREE RINGS Interpretation: dry or wet periods of time

  8. PROXY DATA: LEAVES Interpretation: Climatic regime: tropical, boreal, etc.

  9. Deep Sea Coring Ruddiman, 2008

  10. PROXY DATA: CORE DATA

  11. PROXY DATA: BENTHIC FORAMS

  12. PROXY DATA: PLANKTONIC FORAMS

  13. STABLE ISOTOPES OF OXYGEN OXYGEN: 8 protons/8 neutrons At. Mass = 16 • Isotopes: variants in nature that have more or less neutrons than the norm (dominant) • In the natural world the Standard Mean Ocean Water (SMOW) today contains 2 atoms of Oxygen that have 8 protons and 10 neutrons = mass 18 for every 1000 atoms of “normal” oxygen – mass 16. • This is measured as the del (delta = difference) of that isotope to the norm: i.e. δO18 = 2 o/oo and measurements are in reference to SMOW

  14. STABLE ISOTOPES OF OXYGEN IN SEA WATER H2O OXYGEN in sea water: in reference to SMOW = positive in glacials (more ice) = negative farther back in time (less ice) PROBLEM: no fossil sea water; therefore we rely on measurements from CaCO3 from foram shells, etc. that are in equilibrium with sea water (i.e. proxy data)

  15. ISOTOPIC FRACTIONATION

  16. WHAT CAN INFLUENCE OXYGEN ISOTOPIC RATIOS IN CaCO3 1o: Ice Volume (salinity) – up to 2 o/oo SMOW: - a result of preferentially evaporating H216O from the ocean and accumulating it as ice on land (up to 100m worth of the ocean water) – thus enriching the oceans in H218O 1o: Temperature = ~+0.25 o/oo per drop of a oC

  17. 2o INFLUENCES: OXYGEN ISOTOPIC RATIO INFLUENCES IN CaCO3 Local Salinity: ocean / fresh water / proximity to rivers, etc. Species habitat: where in the water column do they live (temp/salinity) Species fractionation: a poorly understood process

  18. ICE CORE DATA EMPIRICAL AND PROXY DATA EMPIRICAL DATA: Gas bubbles = % CO2, % O2, %N2, etc. • Compare: actual measurements you can compare to values today PROXY DATA: δO18, δC13 , δH2 ,(deuterium), etc. from H2O and correlate it to CaCO3 from Ocean samples • Interpret: e.g. δO18: ice volume, temperature, salinity

  19. ICE CORES

  20. Empirical Interpreted Brook, 2008 Nature

  21. Proxy data: stable isotopes Wikipedia

  22. - SO – WHAT CONTROLS CLIMATE

  23. Gerhard et al., 2001

  24. FEEDBACKS 2o Forcings Continents (latitudes & elevations) Ocean circulation weathering CO2 4o Forcings Volcanic eruptions Sunspots Cycles El Nino/ La Nina Cloud Solar storms 3o Forcings Obliquity Precession Eccentricity CO2 /CH4 1o Forcings Solar Luminosity Atm. Comp. Rohling, et al., (PALAESENS Project mbrs), 2012

  25. Milankovitchcycles(forcing factors)

  26. But it’s also CO2 and here’s the geologic proof: CASE STUDIES: • The Paleocene-Eocene Thermal Maximum (PETM) whereby CO2 increased dramatically and climate warmed dramatically as well • The Azolla event whereby CO2 dimished dramatically – yet temperature didn’t at much – it’s still being studied

  27. The PETM

  28. PETM - THE LAND RECORD

  29. Bighorn Basin • PETM interval in fluvial deposits with excellent alluvial paleosols - seen as color bands, which are soil horizons • Found in Willwood Fm • Reds, purples due to iron oxides in B horizons

  30. Paleosol Density PETM Pre-PETM

  31. Bighorn Basin Climate • Plant fossils and isotopes show Mean Annual Temperature of 20o to 25oC or 68 to 77o F • Similar to Gulf Coast region today

  32. The Azolla event

  33. UNPRECEDENTED DROP IN CO2 the massive decrease in atmospheric CO2? Bujak, pers. Comm.

  34. So what caused the drop in CO2 in the Eocene and since? • Eocene: 800,000 years of sequestration of Azolla organic matter • Slower rates of plate tectonics = lower recycling of carbonate = reduction of CO2 in atmosphere

  35. No Polar Ice Caps P/E World From Blakey (2007)

  36. ARCTIC EVENTS PROXY DATA Brinkhuis et al,, 2006 Moran et al., 2006

  37. ACEX Azolla core • >8 metre ACEX core with 90% Azolla • Azolla occurs as laminated layers • indicates Azolla deposited in situ • bottom-water anoxia at ACEX site Bujak, pers. Comm.

  38. UNPRECEDENTED DROP IN CO2 the massive decrease in atmospheric CO2? Bujak, pers. Comm.

  39. The longer record

  40. THE PRESENTSo what’s going on today?What’s going to happen in the short-term?

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