Ice cores are 4 inch or 6 inch cylinders of ice drilled out vertically by hollow circular bits. In the Northern Hemisphere, ice cores from Greenland are the most common, but ice cores have been recovered and analyzed from Northern Canada and Iceland as well.
Ice cores are relevant to this series—Bringing the Real World to Genesis. In Genesis 1 the events of Creation (including the creation of life and the subsequent destruction of much of that life by a Flood) are described. The author of Genesis never specifies the date of these events. However, subsequent chapters speak of them as if they had occurred only a few thousand years previously. So when the “Real World” is brought to Genesis the question “How old is the world, really?” arises immediately. Each doublet layer in the ice core (cloudy alternating with clear) appears to be a layer of preserved summer snow (cloudy due to dust, pollen, etc.) followed by winter snow (clear). If the number of these (purportedly annual) “doublet layers” vastly exceeds the few thousand years that the Genesis text implies, where does that leave the Bible-believing Christian who also takes Science seriously? This latter question has been directly addressed by a recent Spectrum book, God, Sky and Land: Genesis I as the Ancient Hebrews Heard It to which the reader is referred for further exploration. The question of whether or not those doublet layers really do represent years will be addressed here.
In the Greenland Ice Core Project (GRIP), the limit to the number of layers that can be seen by the naked eye and counted by visual stratigraphy (high resolution scans with visible light) exceeds 60,000 (some observers would place the limit at 90,000) with the total time span represented by the core at more than 135,000 years.
The pressure at depth in an ice sheet is intense enough to compact snow into ice and then, subsequently, to progressively thin each layer as more ice accumulates above. Annual snow layers that were originally half a meter thick when first deposited and less than half that when transformed into ice may be no more than two centimeters in thickness two kilometers down. And yes, ice cores from Greenland do go down two or more kilometers. The GRIP core drilled in 1989-92 extends down 3,029 meters; almost two miles. GRIP provides some of the data for Part 1 and most of the data for Part 2 of this report.
GRIP contains more than 135,000 binary (summer-winter) layers. Most readers will likely assume that there are annual “rings” in the ice cores that can be counted downward from the surface of the core just like starting a count of tree rings from the center of a cut stump. Ice-core chronology is a bit more complex than that. Some, but not all, of that complexity can be ignored since, as already noted, the difference between the few thousand (certainly less than 10,000) years inferred from the Genesis account and the 135,000 enumerated in the GRIP core is more than 10 fold. A year or two one way or another is not going to make much of a difference. If GRIP is correct, then the time that has elapsed since Creation is vastly longer than a “face” reading of Genesis supports.
So just exactly what would we see if we were looking at the GRIP core ourselves? Let’s start at the surface and proceed down. For the first 1,000 meters or so we will we nothing but ice, transparent ice, no sign of annual rings! See the upper panel of Figure 1. The primary tool that scientists use for ice core chronology tracks changes that are invisible to the naked eye. The visible annual rings only come later. All water, including seawater, contains oxygen and hydrogen. The oxygen comes in two slightly different forms—one (O18) being heavier than the other (O16). Water molecules containing the heavier O18 are less likely to evaporate and more likely to precipitate out of the atmosphere as rain. Most evaporation and precipitation occurs in the tropics, with global atmospheric circulation gradually moving the moisture-laden tropical air pole-ward. During this pole-ward journey, precipitation progressively depletes the O18 levels in the residual vapor, with the depletion being most pronounced in colder conditions (heavier molecules drop out of the clouds sooner when it is cold) (Figure 2).
Figure 2 Illustration by Robert Simmons, NASA GSFC.
Thus, the winter snow that falls over Antarctica and the central Greenland ice-sheet will contain less O18 than the snow which falls in summer. This effect is clearly seen in Figure 3 [see top image] , where the O18 content of Greenland snow is displayed as % deviation from oceanic content.
It is easy to document that annual layers are forming at the surface of the snow by simply marking that surface with a “permanent marker” (powdered carbon etc.) at the same time each year for 10 consecutive years and then digging a snow pit and looking at the number of layers. Scientists have done this. Furthermore, each snow layer sandwiched between carbon layers carries within it the characteristic cyclical marker of low O18 content in winter alternating with a higher O18 content in summer.
So annual layers are forming at the surface of the snow even though they cannot—without extra effort—be visually distinguished. When they first become ice, they are 20 or more cm in thickness. The layers only become easily visible to the naked eye as they are compressed and thinned by the increasing weight of the layers accumulating above. They are compressed to approximately one tenth of their original thickness at approximately 1,000 or so meters below the surface. The characteristic O16/O18 cycles are present throughout the clear ice section of the ice core. Look again at Figure 1. These are photographs from an ice core drilled at Summit Greenland near to the GRIP site. In this core 1836 meters down there are clearly defined layers. Even so, it still would be difficult to determine just exactly how many there are—so their number has been assessed by a high-resolution scanner operating with visible light.[i] In this region of the core, where both visible light scanning and O16/O18 ratios can be measured, the number of layers as determined by both methods agrees within a few percent.
It would appear that the scientists are to be believed when they report more than 100,000 annual (doublet) layers in ice cores. The disconnect with the time scale implied in Genesis really does exist. A discrepancy of this magnitude will, sooner or later, need to be addressed. Sections taken from progressively deeper portions of an ice core really are “biopsies” of water and air from a time in the past that can be accurately determined by noting how many O16/O18 cycles exist between that point in the ice core and the surface of the ice sheet. As for the time that life has existed on the earth, those “biopsies”, all the way to the bottom of the core, contain pollen as well as wind-transported leaf-wax from trees indicating that plant life was then thriving at other (warmer!) locations on earth.
There are at least 10 other measurements that behave similarly to the O16/O18 cycle and which have been applied to the transparent upper section of the ice core. Lead levels in the upper transparent layers of the GRIP core vary more than a hundredfold in concentration. Because we know when lead mining began, they provide yet another method of determining whether ice core chronology is to be taken seriously. We will look at how lead levels in the atmosphere have varied throughout the past 2,600 years in Part 2.
Ice cores are relevant to this series (Bringing the Real World to Genesis) for another reason as well. A Noachian Flood lasting one solar year cannot be invoked to explain their existence. Rocky geological layers often give evidence of having been deposited by water, perhaps a flood. To those not familiar with geological processes, it has often seemed possible to ascribe all or most of the multiple geological layers which collectively make up the “geologic column” to deposition by a world-wide, year long flood. Icy geology, as evidenced by the almost two miles of ice of the GRIP core, cannot be similarly disposed of.
—Brian Bull, MD., is professor and chair of the Loma Linda University Medical School department of Pathology and Human Anatomy. He served as editor-in-chief of Blood Cells, an international hematology journal (1984–1993), and as LLU Medical School dean (1994–2003). He is the author of 200 scientific articles, book chapters and monographs.
[i]Svensson A, Nielsen SW, Kipfstuhl S, Johnsen SJ, Steffensen JP, Bigler M, Ruth U, Rothlisberger R. Visual stratigraphy of the North Greenland Ice Core Project (NorthGRIP) ice core during the last glacial period. Journal of Geophysical Research-Atmospheres 2005;110.
Further Reading: God, Sky and Land: Genesis I as the Ancient Hebrews Heard It. Adventist Forum, P.O. Box 619047, Roseville, CA.
Top image: Figure 3 Stable Isotopes and Climate History From Polar Ice cores, Thortsteinn Thorsteinsson, Alfred Wegener Institute for Polar and Marine Research, Geophysics Division, Bremerhaven.
This is a companion discussion topic for the original entry at http://spectrummagazine.org/node/4751