Transcript Dr. Todd Hinkley's

The Nickel NICL Tour
GISP 2D, 2114 m
Detail of time-stratigraphic
record in ice cores
• In some cores, where accumulation rate
is high, sub-annual (seasonal) records
are preserved
• Allows exact age determination of ice,
for thousands of years in the past
The National Ice Core Laboratory
Holocene
115KYBP
New West Antarctic Ice Sheet (WAIS) core
to be drilled during the IPY in ’07 – ‘08
Goals and justification for this new core and site:
Need 80Ky record, from high-accumulation zone,
hopefully with annual layers
• Climate forcing by greenhouse gasses
• Role of Antarc. in initiating rapid climate change
• Relationship between northern, tropical and
southern climates
• Stability of the West Antarctic Ice Sheet and sea
level change
More detailed scientific questions :
• Are the climate changes during the anthropogenic era
unprecedented?
• How has climate varied during the last 10,000 years?
• Do solar variability and volcanic emission affect climate?
• What was the role of the Antarctic in climate change as the last ice
age was ending?
• What are the interactions between terrestrial biology and
biogeochemical cycles?
• What are the interactions between southern ocean biology and
biogeochemical cycles?
• Are microorganisms metabolically active in ancient ice?
• Does the biology within ice sheets reflect the climate when the ice
was deposited?
Ice cores - - not the only game in town.
Other paleoclimate “proxies”:
1. Tree rings
fine time resolution, fine areal emphasis
2. Corals
rings like trees, but tell temp. & chem. of oceans
3. Ocean and lake sediments
very long time record, coarse resolution
4. “Spelean realm”: stalactites, stalagmites
Well dated, long records from groundwater.
5. Packrat middens
Localized, long-term records from pollen
But ice cores aren’t ONLY a tool for
climate change research
One example:
• Ice sheets preserve trace elements
deposited from the atmosphere
• Gives natural (pre-industrial)
abundances, as baseline for
modern, disturbed conditions
Where will the CO2 go after we “run out of gas”
(after a few centuries)
It will return (more slowly) to the various
“reservoirs” in which we store carbon
on this planet
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standing plants (small mass, rapid response)
soils (humus)
surface layers of ocean
deeper ocean
carbonate rocks (huge mass, v. slow response)
THE END
Findings about trace elements
In pre-industrial times, quiescent
worldwide volcano degassing contributed
most of the masses of trace elements in
the ice (much more than can be
accounted for by the dust and sea salt
present).
Another example about the trace element
record of past times:
Pollution to the Antarctic: what’s the evidence of
when industrial pollution started to show up?
Tentative finding: Lead (Pb) isotopes indicate
that it first showed up in the 19th century,
BUT there are intriguing strata of the same
isotopic composition from three centuries
before that.
A third trace-element example:
Volcanic ash blankets that fall onto the
Earth’s surface - - are they big sources
of extra trace metals?
Finding: No, although plumes of quiescently
degassing volcanoes have extra trace
elements, big ash explosions only have the
tiny amounts found in ordinary rock
Core processing line in action
Another (related) example:
• Do falls of volcanic ash (tephra) bring
with them large amounts of excess,
available trace metals, to their localities
of deposition?
• Tephra falls are preserved in ice
Finding:
• Tephra is not a source of extra trace
elements, to the oceans or land on which
it falls
• It has trace element abundance no higher
than ordinary volcanic rock, of its type
(volcanic explosion are high-energy, high-entropy processes,
with little potential for fractionation)
Relative roles of dust and volcano emissions as sources
of atmospheric deposition of trace metals (to ice sheets).
• From field and lab work measuring worldwide magnitude of
volcano trace metal injections into the atmosphere;
and amounts of trace metals in Antarctic ice
• Points to the following:
Volcanoes accounted for most of the atmospheric trace metals in
the pre-industrial environment.
Only in very dusty times does dust account for a big fraction.
Hinkley et al., Earth and Planetary Science Letters, 1999; Matsumoto & Hinkley, same journal, 2001; other papers
A. Countries with formal, dedicated ice
core storage labs
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Argentina - - mountain cores
Australia - - Antarctic cores
Denmark - - Greenland cores
India - - mountain and polar cores
(under construction)
• Japan - - Antarctic cores
• U.S.A. - - polar cores
B. Countries with substantial ice
holdings and facilities for analysis
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China - - mountain and polar cores
France - - Antarctic cores
Germany - - polar cores
Russia - - polar and other cores
(some cores kept in ideal storage conditions
of the East Antarctic Plateau)
• United Kingdom - - polar cores
C.
Countries with expanding field
acquisition and analytical programs,
and planned or needed
storage facilities
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Brazil
Chile
Italy
Switzerland
Storage conditions are favorable for
preserving records of atmospheric gases
• Japanese lab stores ice at
–50o C.to prevent escape
of clathrate hydrates
• U.S. lab stores ice at –36o C.