Assertion: Using ice cores to try to determine the age of the earth is based upon starting suppositions.
December 28, 2006
On December 3, Dr. Hugh Ross’s Reasons to Believe website featured a new result from the Dome C ice core, drilled from on top of the Antarctic Ice Sheet. This ice core was drilled down to 3,190 meters and is supposedly over 800,000 years old in the uniformitarian* timescale.1 The website stated that evidence for the great age of the core is demonstrated by the discovery of the Matuyama-Brunhes geomagnetic reversal at about 780,000 years in the core, based on a recent article from Nature.2 However, this deduction is equivocal, even from a uniformitarian point of view.
The beryllium-10 bump
The geomagnetic reversal was not directly measured in the Dome C ice core. It is a deduction based on a slight increase in the abundance of the radioactive isotope beryllium-10 measured down the core, or a beryllium-10 bump, assumed correlated to the Matuyama-Brunhes geomagnetic reversal.2 This reversal is the last major reversal in the uniformitarian geological timescale before the recent period. The geological column contains dozens of paleomagnetic reversals, assumed to be caused by reversals of the Earth’s magnetic poles. The subject of reversals, and how they fit into the Creation-Flood model is beyond the scope of this article. Russell Humphreys has a good hypothesis on their cause during and right after the Genesis Flood.3
Beryllium-10 is a cosmogenic radioactive isotope formed by cosmic rays in the same manner carbon-14.4 Unlike carbon-14, it is scavenged from the atmosphere in about three weeks to one year. Beryllium-10 has a half life of 1.5 million years.5
However, the researchers arrived at this beryllium-10 bump by indirect methods. First, the bottom of the core between 3,100 and 3,190 meters contains many surprisingly beryllium-10 spikes or strong increases in concentration, making the background analysis of beryllium-10 in the core difficult: “However, their [the spikes] presence makes it very difficult to evaluate the production rate trends in the 10Be profile, which is what interests us here.”6 The origin of these spikes is unknown, but believed to be due to some sort of concentration variation on short spatial scales. So, the researchers apparently ignored the spikes in their calculations, which, in my opinion, is a questionable procedure.
The plot of beryllium-10 at the assumed age of the Matuyama-Brunhes geomagnetic reversal does not look significant. So, the researchers used the medians rather than the means of five measurements within each 55-centimeter long core sample. This procedure reduces the effects of small spikes left in the profile. However, it enhanced the beryllium-10 profile at the desired location at 3,160 meters—again, I would submit, a questionable procedure.
But, there were also enhanced beryllium-10 values at 3,100 and 3,180 meters in the ice core. Why wouldn’t these peaks be the sought-after Matuyama-Brunhes geomagnetic reversal, especially since there are a number of “paleomagnetic excursions” in the normal period since the Matuyama-Brunhes reversal.7 An excursion can be thought of as a decrease in paleomagnetic intensity, assumed to be caused by a failed reversal. Why couldn’t any of these many excursions be correlated to the beryllium-10 bump at 3,160 meters in the Dome C ice core?
A Major Theoretical Problem
The researchers have a major theoretical problem. They assume that during a geomagnetic pole reversal, the intensity of the Earth’s magnetic field decreases tenfold, which allows more cosmic rays to form beryllium-10. The problem is that the effect supposedly occurs only equatorward of 60° latitude, which means that there should be no change in beryllium-10 production above the Antarctic Ice Sheet during a reversal!6,8 So, the process of increasing the concentration over Antarctica under these circumstances becomes speculative, although the formation of beryllium-10, its poleward transport, climatic effects, and its deposition on the ice are complicated and poorly understood.4,9,10
They justify the increase in beryllium-10 at the presumed Matuyama-Brunhes geomagnetic reversal by pointing to a spike in beryllium-10 at about 40,000 years, corresponding to the Laschamp geomagnetic excursion, within their timescale for the Antarctic Vostok ice core. There is another spike at about 60,000 years.10 Each spike supposedly lasted one to two thousand years. These spikes are also found in deep-sea cores.11,12 Researchers use these Vostok spikes as reference horizons to date other ice cores. However, such correlations have not fared well since the spikes are only about twice background levels, there are other spikes but not as high as the two spikes, the spikes are absent where expected in other cores, and they are located at the wrong times in other cores.10
The origin of these beryllium-10 spikes is not known within the post-Flood ice age model, but there are a number of possibilities.4,9,10 The beryllium-10 trend in ice cores could be caused by (1) changes in production rate, (2) changes in the atmospheric circulation, and (3) changes in the precipitation rate.13 The geochemical cycling of 10Be is quite complicated with a number of minor inputs and variations.14
After all the manipulation of the measurements in the Dome C core and the theoretical problems, the researchers express some doubt over their results: “If correct, this provides a crucial tie point between ice cores, marine cores and a radiometric timescale.”6 They are hoping for more than just dating the Matuyama-Brunhes geomagnetic reversal; they hope to tie ice cores with marine deep-sea cores and radiometric dating methods. It is interesting that these three systems are not yet tied together, although it is really the supposed timescale of deep-sea cores that actually “dates” the ice cores, as we will see below.
What about the Old Dates?
What about the old dates of hundreds of thousands of years obtained in Antarctica ice cores? How legitimate are these? First, Antarctic ice cores are not dated by counting annual layers, as is supposedly done in Greenland ice cores, because the snowfall is too light on top of Antarctica. The claimed counting in Greenland cores is based on many assumptions, especially the assumption that the ice is old to begin with.15 Dome C, as well as Vostok, is dated by ice flow modeling and wiggle matching of oxygen or deuterium isotope plots from deep-sea cores: “On the basis of ice flow modelling and a comparison between the deuterium signal in the ice with climate records from marine sediment cores, the ice at a depth of 3,190 m in the Dome C core is believed to have been deposited around 800,000 years ago.”4
Ice flow modeling assumes an ice sheet in equilibrium for millions of years. So, old age is automatically built into the ice cores. Deep-sea cores also have oxygen or deuterium isotope fluctuations. Ice cores are simply wiggle matched to the deep-sea cores, which are then dated by correlation to the astronomical theory of the ice ages or the Milankovitch mechanism, reinforced by radiometric dating of certain key points, called reference horizons.16 The whole enterprise is one big exercise in circular reasoning, sometimes called the reinforcement syndrome.17
Sadly, it appears that Hugh Ross and Reasons to Believe are again unnecessarily aligned with questionable old age deductions. The Scriptures—and the evidence—suggest a recent creation.
- EPICA Community Members, Eight glacial cycles from an Antarctic ice core. Nature 429:623–628, 2004.
- Raisbeck, G. M., F. Yiou, O. Cattani, and J. Jouzel, 10Be evidence for the Matuyama-Brunhes geomagnetic reversal in the EPICA Dome C ice core. Nature 444:82–84, 2006.
- Humphreys, D. R., Reversals of the Earth’s magnetic field during the Genesis Flood. In Walsh, R. E., C. L. Brooks, and R. S. Crowell (editors), Proceedings of the First International Conference on Creationism, Volume II Technical Symposium Sessions and Additional Topics, Creation Science Fellowship, Pittsburgh, Pennsylvania, pp. 113–126, 1986.
- McHargue, L. R. and P. E. Damon, The global Beryllium 10 cycle, Reviews of Geophysics 29(2): 141–158, 1991.
- Yiou, F. and G. M. Raisback, Half-life of 10Be, Physical Review Letters 29(6): 372–375, 1972.
- Raisbeck et al., Ref. 2, p. 82.
- Buyodo, Y. and Valet, J.-P., Global changes in intensity of the Earth’s magnetic field during the past 800 kyr, Nature 399:249–252, 1999.
- Steig, E. J., P. J. Polissar, M. Stuiver, P. M. Grootes, and R. C. Finkel, Large amplitude solar modulation cycles of 10Be in Antarctica: implications for atmospheric mixing processes and interpretation of the ice core record,Geophysical Research Letters 23(5):523–526, 1996.
- Morris, J. D., Application of cosmogenic 10Be to problems in the earth sciences. Annual Review of Earth and Planetary Science 19:313–350, 1991.
- Oard, M. J., The Frozen Record: Examining the Ice Core History of the Greenland and Antarctic Ice Sheets, Institute for Creation Research, El Cajon, California, pp. 101–104, 2005.
- Yiou, F., G. M. Raisbeck, D. Bourles, C. Lorius, and N. I. Barkov, 10Be in ice at Vostok Antarctica during the last climatic cycle. Nature 316:617–618, 1985.
- Raisbeck, G. M., F. Yiou, D. Bourles, C. Lorius, J. Jouzel, and N. I. Barkov, Evidence for two intervals of enhanced 10Be deposition in Antarctic ice during the last glacial period. Nature 326:273–277, 1987.
- Beer, J., et al., 10Be variations in polar ice cores. In Lanyway, Jr., C. C., Oeschger, H., and Dansgaard, W. (editors), Greenland Ice Core: Geophysics, Geochemistry, and the Environment, American Geophysical Union Monograph 33, American Geophysical Union, Washington, D.C., p. 69, 1985.
- Finkel, R. C. and K. Nishiizumi, Beryllium 10 concentrations in the Greenland Ice Sheet Project 2 ice core from 3-40 ka. Journal of Geophysical Research 102(C12): 26,699–26,706, 1997.
- Oard, Ref. 10, pp. 1–199.
- Oard, Ref. 10, pp. 111–122.
- Oard, M. J., Ancient Ice Ages or Gigantic Submarine landslides? Creation Research Society Monograph No 6, Chino Valley, Arizona, pp. 11–13, 1997.
*I am aware that most mainstream scientists consider themselves “actualists” and not uniformitarians. Actualism is similar to uniformitarianism except that the former believes in a few large catastrophes sprinkled throughout earth history, such as meteorite impacts. They also admit that the present is not necessarily the key to the past, but that geology must always believe natural processes operated in the past. I believe this philosophical point of view can be used as an excuse when deductions from the rocks and fossils are contradicted by present processes. But since few people understand the distinction between actualism and uniformitarianism, I will continue using the term “uniformitarian,” especially since this latter doctrine was the philosophical principle used in geology to throw out the Flood.