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

Email: PEBelanger@glassdesignresources.com or Paul.Belanger@DMSN.org

www.denverclimatestudygroup.com/Wips20110909fieldtrip

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 DATAACTUAL 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” DATADATA 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. δO18 = 2 o/oo and measurements are in reference to SMOW

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)

ISOTOPIC FRACTIONATIONISOTOPIC FRACTIONATION

WHAT CAN INFLUENCE OXYGEN ISOTOPIC RATIOS IN CaCO3

11o: Ice Volume (salinity) – up to 2 : Ice Volume (salinity) – up to 2 oo//oo oo SMOW:SMOW:

- a result of preferentially evaporating H- a result of preferentially evaporating H221616O O

from the ocean and accumulating it as ice from the ocean and accumulating it as ice on land (up to 100m worth of the ocean on land (up to 100m worth of the ocean

water) – thus enriching the oceans in Hwater) – thus enriching the oceans in H221818OO

11o: Temperature = ~+0.25 : Temperature = ~+0.25 oo//oo oo per drop of a per drop of a ooCC

OXYGEN ISOTOPIC RATIO INFLUENCES IN CaCO3

Local Salinity: ocean / fresh water / Local Salinity: ocean / fresh water /

proximity to rivers, etc.proximity to rivers, etc.

Species habitat: where in the water Species habitat: where in the water column do they live (temp/salinity)column do they live (temp/salinity)

22o INFLUENCES: INFLUENCES:

Species fractionation: a poorly Species fractionation: a poorly understood processunderstood process

ICE CORE 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

EMPIRICAL AND PROXY DATA

ICE CORES

Brook, 2008 Nature

Empirical

Interpreted

Wikipedia

Proxy data: stable isotopes

- SO – WHAT CONTROLS

CLIMATE

Milankovitchcycles

(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 CO2

• Eocene: 800,000 years of sequestration of Azolla organic matter

• Slower rates of plate tectonics = lower recycling of carbonate = reduction of CO2 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 CO2

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

CO2 for thepast 400 ky

Pliocene levelsof 385ppm

1946 – 1950

svs.gsfc.nasa.gov

2002 - 2006Temperature

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 September1979, and at a record low in September 2007. Source: NASA

WikipediaSolar irradiance: 342 W/m2

Expected levels of CO2 around 2100 for business as usual