CPT Q. 026: Is the geologic column real, that is, do global correlations of fossils and strata actually exist?

Q. 26. You appear to accept the chronostratigraphic validity of the geologic time scale. But the fundamental assumption behind this time scale is that rocks can be correlated by global correlative synchronous time. For example, ‘Cretaceous’ should be the same everywhere independent of lithology and structure. How do you justify this assumption biblically as well as apart from the Bible? Can you explain how time can be the key to correlation if much of the rock record was emplaced during a one-year catastrophe in which local processes and their relative timing would be inherently unpredictable and variable? Gould asserted¹ that the only possible correlation constant between rocks and time was evolution. Since we reject evolution, on what basis then are strata to be ordered and correlated? Furthermore, given the a priori commitments of 18^th and 19^th century intellectuals to deep time, please explain why their time scale should not be viewed as a philosophical assumption, rather than as an empirical conclusion, and how later attempts to justify it empirically were not circular? Finally, recent publications of the International Commission on Stratigraphy have stated that chronostratigraphy and geochronology are merging into one integrated discipline and one integrated time scale. How might this affect your perception of the time scale’s chronostratigraphic validity and its value for your model?

Response: This question fundamentally deals with the issue of whether or not there is a reliable means for dating rocks, or even correlating them across long distances, apart from the fossils they happen to contain.

Intercontinental distinctive lithologies

First of all, distinctive lithologies that correlate across continents, in some cases across most of the earth’s continents, go a long way toward establishing that global correlations indeed are real. Derek Ager, in the very first chapter of his book, The Nature of the Stratigraphical Record,² provides several striking examples of distinctive lithologies that appear in the same place in the vertical stratigraphic sequence on multiple continents across the globe. These examples include:

distinctive lithologies that correlate across continents, in some cases across most of the earth’s continents, [show] that global correlations are indeed real…

Coccolithic limestone (White Cliffs of Dover, etc)

The extremely pure coccolithic limestone that forms the White Cliffs of Dover in England, but also extends across:

• northern France,
• the Netherlands,
• northern Germany,
• southern Scandinavia,
• Poland,
• Bulgaria,
• and Georgia.

This same distinctive chalk formation is also found:

• on the Black Sea coast in Turkey,
• in Israel,
• and in Egypt.

It is also found:

• across the Atlantic in Texas (as the Austin Chalk),
• in Arkansas, Mississippi and Alabama,
• as well as in Western Australia as the Gingin Chalk.

Triassic sequence of rocks (Newark Group, etc)

Another example is the highly distinctive Triassic sequence of rocks:

• originally described and named in Germany, which are also prominently exposed:
• in England,
• in Spain,
• and on the other side of Europe in Bulgaria.
• Essentially identical Triassic rocks are found, as the Newark Group, along the eastern seaboard of the U.S.
• and across the U.S. south and southwest, in Oklahoma, Texas, New Mexico, Colorado, Utah, and Arizona.

I personally grew up in western Texas where these rocks are prominently exposed and have spent most of my life living in the southwestern U.S. The continuity and lateral uniformity of these distinctive red Triassic rocks has never ceased to amaze me.

Lower Carboniferous (Mountain Limestone, Redwall Limestone, etc)

Yet another example Ager describes is what in England was originally called the ‘Mountain Limestone,’ which is a distinctive feature of Lower Carboniferous, or Mississippian, rocks throughout the world. Outside of Europe, this distinctive limestone includes:

• the limestone of Empire State quarry in Indiana that produced the facing for the Empire State Building in New York City,
• the Redwall Limestone of the Grand Canyon,
• the Rundle Limestone that forms the impressive escarpment of Mount Rundle above Banff in Alberta, Canada,
• the Lisburne Limestone in Alaska,
• and the even limestone that caps Mt. Everest in Tibet.

In the first chapter of his book, Ager catalogs nine other deposits with highly distinctive lithologies, which occur at well-defined positions in the vertical sedimentary sequence from late Precambrian upward and are nearly global in their lateral extent. These distinctive units appear to provide a solid lithological basis for concluding that the stratigraphic record has global and temporal coherence.

Relative radioisotope dating

To me, however, there is an even more convincing category of evidence which points to this same conclusion. I am persuaded that radioisotope methods, applied carefully and interpreted in terms of the relative (not absolute) dates they yield, provide a highly reliable means for correctly ordering rock formations in a temporal manner, across the entire face of the earth, independent of their lithology and fossil content. Much of my confidence on this issue comes from the research my colleagues and I undertook as part of the Radioisotopes and the Age of the Earth (RATE) project during the period 1997-2005.

radioisotope methods, applied carefully and interpreted in terms of relative dates, provide a highly reliable means for correctly ordering rock formations in a temporal manner, across the entire face of the earth…

One of the very basic issues our team addressed had to do with the overall amount of nuclear decay that has occurred since the earth was created and also since the first sedimentary rocks containing fossils of multicellular animals were deposited. The essential question here is, since the earth was created, just how much radioactive decay has occurred—is it billions of years’ worth at present rates, or only a few thousands of years’ worth? Our firm conclusion was that indeed several billions of years’ worth of nuclear decay, at presently measured rates, has taken place since the earth’s rocks were originally created.

Uranium lead dating in zircon

One of the cleanest lines of support for this conclusion lies in the uranium and lead isotope concentrations found in zircon crystals, which are abundant in granitic rocks. The zirconium atoms in the zircon (ZrSiO4) lattice can be readily replaced by other high field strength atoms such as uranium and thorium. Zircons therefore typically contain significant concentrations of uranium, up to about 1% by weight. On the other hand, the zircons, when they crystallize and grow, strongly exclude atoms like lead. Therefore essentially all the lead found in a zircon is radiogenic lead— 206Pb from 238U decay, 207Pb from 235U decay, and 208Pb from 232Th decay. Because zircons in essentially all cases contain no detectable non-radiogenic lead, that is, 204Pb, one can be confident that the radiogenic lead present is indeed the product of nuclear decay of the uranium and thorium originally resident within each individual zircon. Moreover, zircons are extremely hard and have a high melting temperature and so are resistant to degradation. They are therefore ideal candidates for U-Pb dating and have been used widely to date crystalline crustal rocks. For basement granitic rocks it is common to obtain zircon U-Pb dates exceeding a billion years. (Such dates, of course, are predicated on the assumption that nuclear decay rates have been constant since the earth’s formation, an assumption our RATE research showed not to be true.)

Zircons not only capture and preserve the lead generated from uranium alpha decay, but they also commonly preserve the physical evidence of much rarer uranium spontaneous fission. When a uranium nucleus fissions, or splits, inside a zircon, the two fragments fly apart at high velocities and produce tracks of damage in opposite directions in the surrounding zircon lattice. If an interior surface of a zircon is exposed by grinding, then polished, etched with acid, and examined under a light microscope, one can count the number of tracks within a given field of view to determine the density of tracks per unit of surface area. If one also measures the uranium concentration in the zircon, it is possible to calculate an age for the zircon from the density of fission tracks. Many studies, including one which our RATE team conducted, confirm that the zircon fission track age closely matches the U-Pb age, provided the zircons have not been heated above the fission track annealing temperature, which is on the order of 250 °C. The main point here is that fission tracks represent tangible, physical evidence of millions to billions of years’ worth of nuclear fission, in terms of fission rates we measure today. Hence one simply cannot deny that billions of years’ worth of nuclear decay has occurred over the span of earth history.

The uranium in zircons also often generates physical damage in the form of radiohalos in minerals hosting the zircons such as biotite and fluorite. For uranium concentrations commonly found in zircons, about 100 million years’ worth of nuclear decay at today’s rates are typically required to produce a mature radiohalo. The RATE research documented thousands of such radiohalos in granitic plutons emplaced during the Flood and also in Flood sediments metamorphosed during the cataclysm. The existence of uranium radiohalos in rocks formed during the Flood further testifies that several hundred millions years’ worth of nuclear decay, at present rates, during the span of that year.

Another important line of evidence for a vast amount of nuclear decay in the earth’s rocks since creation is the high levels of radiogenic helium we documented still to reside inside zircons from continental basement granitic rocks having U-Pb dates of 1.5 billion years. In one case we found some 80% of the helium from 1.5 billion years’ worth of uranium decay still physically present within the tiny zircon crystals. The remarkable finding, of course, was that the diffusion rate of helium we measured for these zircon crystals constrained the time that the helium could have persisted at these levels to be only about 6000 years.

Our RATE team concluded the only way all these observations could be fit together in a consistent manner, one that also happens to agree with the Biblical record, is for a large amount of nuclear transformation—some four billion years’ worth at today’s rates—to have occurred as God fashioned the material earth, but before He created plants on creation Day three. Moreover, to account for the large additional amounts of nuclear decay products, fission tracks, and other evidences of nuclear decay such as radiohalos across the portion of the geological record produced by the Flood, there had to be a second episode of accelerated nuclear decay, corresponding to 500-600 million years’ worth of decay at today’s rates during the year of the Flood. The logic to me for these conclusions seems nearly air-tight. If anyone can suggest another way to fit these main pieces of the puzzle together, I am certainly eager to listen and to engage on this topic.

Summary

Returning to the original question, I conclude from our RATE research that radioisotope dating methods in most, but not all, cases provide reasonably accurate relative dates for the earth’s rocks, at least to those to which they can be applied. As such, these methods do indeed provide a coherent global chronostratigraphic framework, which, albeit not absolute in terms of time, nevertheless is not circular, is not based on fossils, and is not based on evolution. Is it justifiable from a Biblical standpoint? The description I provided in the preceding paragraph appears to be harmonious as far as I can discern. As to the importance of having or not having such a coherent chronostratigraphic framework, I believe it is nearly essential to have such a framework, if we, who believe that all Scripture is given by inspiration by God, desire to account for the details of the geological record in terms of the Flood and defend Genesis 1-11 in a credible manner.