|
 It
is not uncommon to read that ice cores from the polar regions contain
records of climatic change from the distant past. Research teams from the
United States, the Soviet Union, Denmark, and France have bored holes over
a mile deep into the ice near the poles and removed samples for analysis
in their laboratories.
Based on flow models, the variation of oxygen isotopes, the concentration
of carbon dioxide in trapped air bubbles, acid concentrations, and
particulates, they believe the lowest layers of the ice sheets were laid
down over 160,000 years ago. Annual oscillations of such quantities are
often evident in the record near the top of the ice sheets.
 Are
these records in the ice legitimate? Do they cause a problem for the
recent‑creation model of earth history? What are we to make of these data?
This article will show that the great ages reported for the bottom layers
of ice sheets depend on assumed models of past climate. Direct counting
of annual layers is valid downward in the ice sheets for 2-3,000 years in
the past, but prior to that there are many gaps in the record and the
layers are probably not due to annual accumulation. An alternative model
of ice sheet formation following the Flood described in Genesis will be
suggested.
World War II Airplanes Under the Ice
The
Greenland Society of Atlanta has excavated a 10‑foot diameter shaft in the
Greenland ice sheet in the late 1980’s to remove two B‑17 Flying
Fortresses and six P‑38 Lightning fighters trapped under an estimated 250
feet of ice for almost 50 years (Bloomberg, 1989). Aside from the
fascination with salvaging several vintage aircraft for parts and movie
rights, the fact that these aircraft were buried so deeply in such a short
time focuses attention on the time scales used to estimate the
chronologies of ice core data.
If
the aircraft were buried under about 250 feet of ice and snow in about 50
years, this means the ice sheet has been accumulating at an average rate
of five feet per year. The Greenland ice sheet averages almost 4000 feet
thick. If we were to assume the ice sheet has been accumulating at this
rate since its beginning, it would take less than 1000 years for it to
form and the recent‑creation model might seem to be vindicated.
Greenland Ice Cores
However, life is never as simple as implied above. In making our
calculations, we did not take into account the compaction of the snow into
ice as it is weighted down by the snow above. Neither did we consider the
thinning of ice layers as the tremendous weight above forces the ice at
lower levels to squeeze out horizontally. More importantly, we did not
consider the average precipitation rate and actual depths of ice for
different locations on the Greenland ice sheet.
When
these factors are taken into account, the average annual thickness of ice
at Camp Century located near the southern tip of Greenland is believed to
vary from about fourteen inches near the surface to less than two inches
near the bottom (Hammer, et al., 1978). If, for simplicity, we assume the
average annual thickness to be the mean between the annual thickness at
the top and at the bottom (about eight inches), this still gives an age of
less than 6000 years for the 4000‑foot‑thick ice sheet to form under
uniformitarian conditions.
Although occasional ambiguities occur, it is relatively easy to count
annual layers downward from the surface through considerable depths in the
Greenland ice sheet. This is possible because of the large precipitation
rates in Greenland and the preservation of the effects.
It
is also possible with a high degree of accuracy to cross check the
counting of layers with occasional peaks in acidity and particulates from
the fallout of historic volcanic events. Hammer, et al. (1978) have
correlated the peaks in the mean acidity of annual layers from 553 to 1972
A.D. with historic volcanic events. About a dozen historical volcanic
eruptions are evident in the ice core from Crete in central Greenland.
Several unknown eruptions are also documented in the ice core record.
The
confidence in the chronology becomes less the lower in the ice sheet one
goes, however. The amplitude of the oscillations slowly decreases relative
to other factors, and historic markers are fewer and farther apart.
Glaciologists now claim that they can visually count up to 50,000 annual
layers in he Greenland ice sheet (Alley, et al., 1997). However, the
assumption that the lower layers have accumulated annually is highly
suspect. The deeper one goes in the ice the more difficult it is to
detect a layer and the poorer the continuity of the record.
Antarctic Ice Cores
The
claims that layers of ice were formed 160,000 years ago or more come
primarily from interpretation of ice cores in Antarctica (Jouzel, et al.,
1987; Barnola, et al.,1987). The Soviet Antarctic Expeditions at Vostok in
East Antarctica recovered an ice core which was almost 7,000 feet long in
a region where the total ice thickness is about 12,000 feet (Lorius, et
al., 1979; Lorius, et al., 1985). Since the current precipitation rate is
so much less than Greenland (on the order of one inch per year) the crude
calculation of age, without corrections for compression and horizontal
motion for the lowest layers is more than 100,000 years.
However, such estimates are critically based on the assumption that the
accumulation rate has not varied greatly over the past. Unlike the
Greenland ice cores, annual oscillations of Oxygen-18 and other parameters
cannot be traced deeply into the ice sheet on Antarctica. In Greenland,
the high precipitation rates not only provide relatively thick annual
layers for analysis, but the accumulating snow quickly seals off the ice
beneath and protects the record from metamorphosis by pressure and
temperature changes in the atmosphere. In Antarctica, by the time the ice
has been buried deeply enough to no longer be influenced by the
atmosphere, annual variations have been greatly dampened by diffusion
(Epstein, et al., 1965; Johnsen, et al., 1972).
The
technique used to estimate the age of an ice layer deep in the ice sheet
is to measure its Oxygen-18 content and compute the atmospheric
temperature which is observed to produce such concentrations today (Jouzel
and Merlivat, 1984). Through a second‑known relation between temperature
and precipitation rate, again observed in today's atmosphere, the
accumulation rate for a given layer is calculated (Lorius, et al., 1985).
Once the accumulation rate is calculated for each layer, the depth and age
for each layer in the ice is calculated by integrating the annual
accumulation downward from the surface.
There are several historical markers in Antarctica
which can be used to cross check these calculations for the past few
thousand years. But historical volcanic events are not known beyond a few
thousand years in the past which provide any certainty to the calculation
of age. This method would be reasonably reliable if precipitation rates
had been similar in the past. However, some creationist models predict
significant quantities of snow immediately after the Flood (Oard, 1990).
Perhaps as much as 95% of the ice near the poles could have accumulated in
the first 500 years or so after the Flood.
The Age of the Earth
From
a creationist perspective, it would be extremely valuable to thoroughly
explore these ice‑core data. We would not assume that the precipitation
rate has always been similar to that of today. We would expect
considerably higher precipitation rates immediately following the Flood.
The layers of ice near the bottom of the core should be thicker than
expected by the uniformitarian model and contain unusual excursions in
Oxygen-18, acidity, and particulates compared to levels higher in the
core. The "annual" layers deep in the Greenland ice sheet may be related
to individual storms rather than seasonal accumulations.
Preliminary results from research on these cores do indeed show large
concentrations of dust, salt, acidity, and volcanic particulates in the
bottom layers of ice. Calculations of the number of layers laid down
assuming the ice sheet accumulated rapidly near the bottom show that as
many as 100 storms may have swept the polar regions each year accompanied
by frequent volcanic eruptions. These conditions are consistent with the
model of the post-Flood world in which the atmosphere was still stormy and
filled with excess water vapor and debris from the catastrophic events of
the Flood and the mountain-building of the post-Flood world.
Nothing in the ice‑core data from either Greenland or Antarctica requires
the earth to be of great age. In fact, there are good reasons to believe
that the ice cores are revealing important information about conditions
following the Flood of Genesis and a recent formation of thick ice sheets.
Reports of ice‑core data containing records of climatic changes as far
back as 160,000 years in the past are dependent upon interpretations of
these data which could be seriously wrong, if the Genesis Flood occurred
as described in the Bible. Continuing research on ice‑core data should be
a high priority for creationist researchers.
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J.J. Fitzpatrick, P.M. Grootes, G.A. Zielinski, M. Ram, G. Spinelli, and
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Barnola, J.M., D. Raynaud, Y..S. Korotkevich, and C.
Lorius, 1987. "Vostok ice core provides 160,000‑year record of atmospheric
carbon dioxide." Nature, 329:408.
Bloomberg, R., 1989. "WW II planes to be deiced." Engineering Report,
March 9.
Epstein, S., R.P Sharp, and A.J. Gow, 1965. "Six‑year record of oxygen and
hydrogen isotope variations in south pole firn." Journal of Geophysical
Research, 70:1809.
Hammer, C.U., H.B. Clausen, W. Dansgaard, N. Gundestrup,
S.J. Johnsen, and N. Reeh, 1978.
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cores by flow models, isotopes, volcanic debris, and continental dust."
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Hammer, C.U., H.B. Clausen, and W. Dansgaard, 1980.
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sheet evidence of post‑glacial volcanism and its climate impact."
Nature, 288:230.
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profiles through the Antarctic and Greenland ice sheets." Nature,
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Jouzel, J. and L. Merlivat, 1984. "Deuterium and oxygen-18 in
precipitation: Modeling of the isotopic effects during snow formation."
Journal of Geophysical Research, 89:11, 749.
Jouzel, J., C. Lorius, J.R. Pent, C. Genthon, N.I. Barkov. M. Kotlyakov,
and M. Petrov, 1987. "Vostok ice core: A continuous isotope temperature
record over the last climatic cycle (160,000 years)." Nature,
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Lorius, C., L. Merlivat, J. Jouzel, and M. Pourchet, 1979. "A 30,000‑yr
isotope climatic record from Antarctic ice." Nature, 280:644.
Lorius, C., J. Jouzel, C. Ritz, L. Merlivat, N.I. Barkov, YS. Korotkevich,
and VM. Kotlyakov, 1985. "A 150,000‑year climatic record from Antarctic
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Monograph, 243 pp.
* Dr. Larry Vardiman is Chairman of the Institute of
Creation Research, Astro/Geophysics Department:
www.ICR.org. This article is an updated version of Impact Article
#226 published by The Institute for Creation Research in April, 1992. |
