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

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

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 19 th 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

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 –standing plants (small mass, rapid response) –soils (humus) –surface layers of ocean –deeper ocean –carbonate rocks (huge mass, v. slow response)

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

THE END

Ice Core Lab Floor Plan

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 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 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 Brazil Chile Italy Switzerland

Storage conditions are favorable for preserving records of atmospheric gases Japanese lab stores ice at –50 o C.to prevent escape of clathrate hydrates U.S. lab stores ice at –36 o C.