FIELD TRIP: USGS CORE LAB / ICE CORE LAB Friday September 9, 2011 Western Interior Paleontological Society Paul E. Belanger, Ph.D. WIPS Past-President Research Associate – Denver Museum of Nature and Science or

USGS CORE LAB / ICE CORE LAB Friday September 9, 2011 Western Interior Paleontological Society SPECIAL THANKS TO OUR HOSTS: John Rhoades Casey McKinney Richard and other personnel in the Ice Core Lab

Western Interior Paleontological Society Lunch/Presentation: 11:30-12:45 data: empirical vs. proxy stable isotopes relevance of ice core data to global warming Rock lab tour 12:45-2p.m.: CL-1 Core, Montrose County, Colorado Ice Core Lab repository Greenland and Antarctic Ice cores: 2-3 p.m.

DATA Western Interior Paleontological Society

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

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

“PROXY” DATA DATA BY WHICH WE MAKE INTERPRETATIONS

EARLY PROXY DATA: TREE RINGS Interpretation: dry or wet

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

Deep Sea Coring Ruddiman, 2008

PROXY DATA: CORE DATA

PROXY DATA: BENTHIC FORAMS

PROXY DATA: PLANKTONIC FORAMS

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. δO 18 = 2 o / oo and measurements are in reference to SMOW

STABLE ISOTOPES OF OXYGEN IN SEA WATER H 2 O 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 CaCO 3 from foram shells, etc. that are in equilibrium with sea water (i.e. proxy data)

ISOTOPIC FRACTIONATION

WHAT CAN INFLUENCE OXYGEN ISOTOPIC RATIOS IN CaCO 3 1: Ice Volume (salinity) – up to 2 o / oo SMOW: 1 o : Ice Volume (salinity) – up to 2 o / oo SMOW: - a result of preferentially evaporating H 2 16 O from the ocean and accumulating it as ice on land (up to 100m worth of the ocean water) – thus enriching the oceans in H 2 18 O 1: Temperature = ~+0.25 o / oo per drop of a o C 1 o : Temperature = ~+0.25 o / oo per drop of a o C

OXYGEN ISOTOPIC RATIO INFLUENCES IN CaCO 3 Local Salinity: ocean / fresh water / proximity to rivers, etc. Species habitat: where in the water column do they live (temp/salinity) 2 INFLUENCES: 2 o INFLUENCES: Species fractionation: a poorly understood process

ICE CORE DATA EMPIRICAL DATA: Gas bubbles = % CO 2, % O 2, N 2, etc. Compare: actual measurements you can compare to values today PROXY DATA: δO 18, δC 13, δH 2,(deuterium), etc. from H 2 O and correlate it to CaCO 3 from Ocean samples Interpret: e.g. δO 18 : ice volume, temperature, salinity EMPIRICAL AND PROXY DATA

ICE CORES

Brook, 2008 Nature Empirical Interpreted

Wikipedia Proxy data: stable isotopes

- SO – WHAT CONTROLS CLIMATE

Milankovitch cycles (forcing factors)

HERE’S THE LONG TERM RECORD Shellito Fricke Jacobs

WHAT CONTROLS THE LONG-TERM RECORD? IS IT STRICTLY CONTINENTAL POSITIONS AND OCEANIC CIRCULATION?

the massive decrease in atmospheric CO2? Bujak, pers. Comm. UNPRECEDENTED DROP IN CO 2

Eocene: 800,000 years of sequestration of Azolla organic matter Slower rates of plate tectonics = lower recycling of carbonate = reduction of CO 2 in atmosphere So what caused the drop in CO2 in the Eocene and since?

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

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

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.

the massive decrease in atmospheric CO2? Bujak, pers. Comm. UNPRECEDENTED DROP IN CO 2

THE PRESENT So what’s going on today? What’s going to happen in the short-term?

Today’s Unique Event: Anthropogenic Global Warming Today CO 2 for the past 400 ky Pliocene levels of 385ppm

1946 – 1950 svs.gsfc.nasa.gov

Temperature svs.gsfc.nasa.gov

Arctic Sea Ice Extent If sea-ice continues to contract rapidly over the next several years, Arctic land warming and permafrost thaw are likely to accelerate. David Lawrence, NCAR Satellite imagery of sea ice extent in September 1979, and at a record low in September Source: NASA

Wikipedia Solar irradiance: 680 W/m 2 Solar irradiance: 342 W/m 2

Expected levels of CO2 around 2100 for business as usual