C-14 Dating May Be Wrong Before 2OOO B.C.

Editor's Note: This month's feature summarizes some recent developments in the interpretation of radiocarbon dates. Readers who are interested in more detail may obtain back issues and a subscription to Origins by writing the Geoscience Research Institute, Loma Linda University, Loma Linda, California 92354.

It is important for the reader to recognize that the evidence and the conclusions reported in this article, as well as others of similar nature, should not be classified as "proof" for the Bible. It is more appropriate to classify such material in terms of success in interpreting the results of scientific investigation from viewpoints that are consistent with the teaching of Scripture. A conversion of radiocarbon ages into real time on a basis that conforms to the chronological data given in the Bible requires peat and sediment accumulation rates immediately following the Flood that are much greater than would be expected on the basis of data from recent historical times. Hence such conversion is not acceptable to individuals who base their views primarily on the conclusions that are in current favor in scientific circles.

WHEN WILLARD LIBBY developed the radiocarbon dating technique soon after World War II, he gave archeologists, biologists, and countless others an apparently dependable dating tool that few have seriously questioned since.

When carbon dating is applicable most scientists will give it heed, what ever their study, be it the movement of glaciers or the development of human civilization.

Until recently there was little reason to suspect that anything could challenge the integrity of a tool that seemed to be gaining credibility with use. Dates positively established by independent means generally agreed with C-14 dates within less than 150 years. Going back in time, however, archeological dates become less precise and thus less useful in checking the accuracy of C-14. Before 2,000 B.C., in fact, C-14 is virtually on its own, free of all precise cross-examination.

Even so, current archeological and geological inferences on dates prior to 2,000 have left little reason to believe that C-14 abruptly goes wrong between two thousand and three thousand B.C., the approximate time of the Flood. Popular assumptions on the development of civilization or the recession of glaciers find ready support in the full 50,000- year range of C-14.

Until recently, creationists have been unable to present a serious scientific challenge to the long-age implications of C-14. Now, however, there is evidence in ancient peat bogs and sediment accumulations that hints at a serious flaw in the use of C-14 before 2,000 B.C. This evidence has been described in a recent issue of Origins, published by the Geo science Research Institute. ¹

Carbon-14 is absorbed into the life cycles of all living matter. But once the organism dies, its C-14 level begins to drop by a slow and regular process of radioactive decay. Within 5,730 years it will have half the C-14 it began with, and half again (down to one fourth the original) in another 5,730 years. This regular decay from a known starting point makes C-14 an obvious timing device. In theory, the lower the C-14, the older the specimen.

In practice, however, a low C-14 concentration could indicate something other than a long period of radioactive decay from an initially high level: a low level of C-14 to begin with. If so, a specimen could be far younger than its C-14 content would seem to indicate.

A known (or assumed) beginning C-14 level is therefore crucial to radiocarbon dating. Since C-14 dates have correlated roughly with dates determined by other means until about 2,000 B.C., scientists have been able to assume that atmospheric C-14 levels were virtually constant at least till then.

Archeological dates and C-14 have not always agreed exactly. Conditions such as temperature of the planet and geomagnetic and solar magnetic fields belting the globe have produced known alterations in atmospheric C-14, causing C-14 dates to differ somewhat from real time.

Before 2,000 B.C. there is little way of checking against other hard evidence, since archeological dates prior to that time may be fogged by subjective and interpretive assumptions.

Relationship to Tree-Ring Dating

The most ambitious attempt to trace C-14 accuracy before 2,000 B.C. has been made by the Laboratory of Tree-Ring Research directed by C. W. Ferguson at the University of Arizona. His guiding assumptions are that one ring means one year, that ancient weather trends produced the same ring pattern in every tree affected, and that ancient weather was similar to today's.

By synchronizing or matching distinctive ring patterns of many overlap ping wood specimens from scores of trees, Ferguson's laboratory has constructed a master ring sequence extending back as far as 5,400 B.C. When checked against C-14, the two dating methods have been found in rough agreement, thus lending apparent validity to C-14 dates prior to 2,000 B.C.

Still, the ring technique is open to serious question. ² The Bristlecone Pine has been known to produce less than one ring a year. But even with a steady one-ring-a-year, ring patterns often lack the distinctiveness (ring-width variation) needed to positively place a given specimen in a master sequence. Furthermore, patterns that are distinctive often vary significantly from one side of a given tree to the other. In fact, plain guessing can be avoided in many cases only by relying on C-14 to derive a ball park location of a specimen in the master-ring sequence. But even that does not solve all problems. Says Ferguson, "I often am unable to date specimens with one or two thousand rings against a 7,500-year master chronology, even with the 'ball-park' placement provided by a radiocarbon date." ³

In any case, tree-ring dating is semidependent on C-14, thus possibly eliminating any major discrepancy be tween C-14 and the rings almost by definition. The rings, then, may actually serve to hide the real truth about C-14. Peat bogs and sediments seem to tell a different story. Robert H. Brown's study involved a statistical analysis of age-depth relationships of more than 100 lakes, ocean sediments, and peat bogs scattered throughout the world. He drew most of his data from Radiocarbon, a journal that publishes nothing but radiocarbon age determinations re ported by numerous C-14 laboratories.

If C-14 dates were valid before 2,000 B.C., not only would peat and sediments be older with depth—as all data shows—but also both would be expected to be older on the average in approximately direct proportion to depth.

Twice as deep, for example, would mean approximately twice as old. But most of the lakes and bogs bear C-14 ages too old for their depth twice as deep, five times as old, in some cases.

Two explanations would be that the deeper material was packed down, or it accumulated slower than did shallower layers. But according to Brown's analysis neither explanation will serve. A layer of peat cannot be squeezed into one fifth its size. In its natural state it is not the fluffy stuff you put on your gar den. Neither can sediment be com pressed sufficiently to account for the C-14 ages of deeper sediments.

Slower accumulation is equally unlikely. If anything, both peat and sediments were accumulating faster thou sands of years ago than today. Peat grows best in a cool (but not arctic), damp climate. In more recent millennia the climate of the planet has been warmer and drier, and peat growth has accordingly slowed considerably. Slow-growing upper (recent) layers, then, should show a far greater age spread for a given thickness than the rapidly grown lower layers. But, in general, C-14 shows the opposite.

One explanation is that sometime prior to 2,000 B.C., the atmosphere contained no measurable C-14. After that, there apparently was a major atmospheric change that resulted in a build-up of C-14 in the atmosphere over several centuries. That would mean that two organisms that died less than one thousand years apart could show a C-14 age difference as great as 40,000 years if one organism died just before C-14 began to appear and the other died after it approached present levels.

In a critical transition period a radio carbon year could well refer to a month or less of actual time. That would ex plain why so much C-14 time passes over so little peat and sediment at deeper levels.

This brings into new focus a few C-14 dates previously considered too freakish to warrant serious attention. A frozen musk ox found at Fairbanks Creek, Alaska, had scalp muscle tissue 24,000 years old and hair 17,200 years old ac cording to C-14 dating. At least three other frozen animals, two mammoths and a mastodon, have been found with parts of their bodies with C-14 ages far different from other parts or from surrounding plant life that perished with or shortly after the animals.

Given the data from the peat and sediment accumulations this should come as no surprise. Since hair is constantly replaced, it provides an up-to-the-minute readout of the C-14 level in the food supply at the death of the animal. But slower-growing body parts such as bone or muscle tissue might be several years out of date. That lag during a period of rapidly rising C-14 could cause a bone of a 10-year-old mastodon to appear thousands of years older than its hair.

Rampart Cave, located at the lower end of Grand Canyon, offers another example of the possible time-inflating capacity of C-14. The cave contains almost 200 cubic yards of stratified animal dung deposits, mostly from the extinct Shasta ground sloth. ⁴

From about 13,000 to 11,000 radio carbon years ago (a span of 2,000 years) the sloths deposited a layer of dung about 70 centimeters thick, by far the most dung of any comparable previous period. Given the size of the Shasta sloth, three to four hundred pounds, that's not much about one cubic foot per year, or less than one week's elimination from one healthy adult ground sloth. Could that really be? For a layer 70 centimeters thick, 200 years would seem far more reasonable than 2,000.⁵

Brown's conclusions do not purport to entirely destroy the credibility of C-14 before 2,000 B.C. Though C-14 dates as such may be wrong, he considers the C-14 sequence to be probably correct. This would mean that a specimen found to be 30,000 years old by C-14 is probably as old as all others indicating 30,000, and older than one 10,000 C-14 years old, if only by a few real years.

Development Can Be Traced

The development of early civilizations, then, can still be traced with C-14. So far, C-14 sequence reveals that the earliest civilization began in the Mideast and from there spread throughout the globe. Genesis 11:8 says: "So the Lord scattered them abroad from there [Babylon, or present-day Iraq] over the face of all the earth" (R.S.V.). Rightly understood, C-14 may prove a valuable asset to creationists.

Since pre-Flood organic material has an infinite C-14 age—50,000 years or more—Brown concludes that there was probably an undetectable concentration of C-14 in the atmosphere before the Flood. But with the Flood could have come cataclysmic changes, bringing a rapid rise in C-14 concentration and a precipitous drop in C-14 from 50,000 to 4,000 radiocarbon years in comparatively few actual years.

In a later issue of Origins, Brown describes a triple impact that the Flood could have had on C-14 levels.6 First, the mere burying of a major portion of the earth's carbon-bearing plant life could in itself account for most of the expected change in C-14 concentration, even if C-14 were produced at the same rate before the Flood as after. An analogy might explain. With five drops of red food coloring (C-14), the smaller the cake (regular carbon), the redder it would be (the higher the proportion of C-14). In burying quantities of regular carbon, the Flood had the effect of diminishing and therefore "reddening" the cake, that is, of increasing the pro portion of C-14 in the air and living matter.

Second, the Flood may have brought with it a drier atmosphere, thus permit ting a rise of atmospheric C-14. Genesis 2:5, 6, suggests that pre-Flood atmosphere had nearly 100 percent humidity. In the upper atmosphere, such humidity would restrict the production of C-14. Flood water could have come partly from this vapor shield, leaving behind a drier atmosphere more open to C-14 production. 

Third, the geomagnetic field belting the earth may have been stronger before the Flood, also reducing pre-Flood C-14 levels. Put together, these factors could place a specimen up to 66,000 radiocarbon years beyond its real age, if C-14 age could be extended that far. And 66,000 is far more than we'd ever have to subtract from the oldest C-14 date to accommodate a flood less than five thousand years ago.