Is There a "Younging Up"in Geologic Column?

By Jon Covey, B.A., MT(ASCP)
Edited by Anita K. Millen, M.D., M.P.H., M.A.

Dr. Kurt Wise, remarked that one problem creationists have to explain is the apparent "younging up" of radiometrically determined ages of rocks in the geological column. Wise, a former Ph.D. graduate student of Stephen Jay Gould and currently professor of biology and geology at Bryan College, ‘wisely’ sides with the Biblical information and believes the earth is young, although current scientific consensus contradicts this. How do we explain the tendency of the rocks at the bottom of the geological column date the oldest and the ones at the top date the youngest?

Not long ago, we published Robert Brown’s article Radioisotope Age  on why single source lava flows show "younging up" in the geological column even though the lava is all the same age. Argon rises to the top of the magma chamber and is concentrated there. As the magma flows up into the overlying strata and out of the volcano, it cools. Some of the Argon-40 never gases out of the magma, giving the impression of great age. Also, some of the argon reenters the magma. As the volcano continues to erupt, magma depleted of argon flows out on top of the earlier deposited lava and appears younger than the lava beneath it, although it is from the same melt and has the same age. It is not unusual to find reports of recent lava flows dating several hundred thousand years old or millions of years old when dated by the potassium/argon method.

Uranium/lead dating can produce a similar "younging up" in lava from the same source. The earth’s mantle has much lower concentrations of uranium and thorium salts and compounds than are found in rocks such as granite and rhyolite. These isotopes are "dissolved" in such rocks. Uraninite, UO₂, has a very high melting point 2878° C. The upper portion of a magma chamber is in contact with cooler rock, making the magma cooler. This cooling causes the UO₂ to crystallize and fall towards the bottom of the magma chamber. This process of fractional crystallization enriches the lower magma with uranium and depletes the upper magma. In the upper portion of the chamber, the uranium-poor magma leaves the chamber and continues upwards. The ratio of uranium to lead in this magma is significantly lower than at the bottom of the magma chamber. The uranium-poor portion of magma would date much older than the magma that comes out later, even though it’s all from the same melt.

I explained this to Dr. Brown and at first he was very excited, since it fit in so well with his own ideas. After he discussed them with an outstanding geologist at Loma Linda University, he said that fractional crystallization of uranium and thorium compounds doesn’t happen because their concentrations are low (only a few parts per million). This was frustrating news to me since I thought I was on to something really significant. Here were two independent dating methods that could be explained in terms of geochemical and geophysical processes rather than the result of radioactive decay over time. Both methods would yield progressively older dates the deeper the rocks were sampled. Our explanations made sense and they explained why rocks seem to "young" up. There are many other factors to consider, as well, and we will discuss these later on.

I wasn’t about to give up and started surfing the Internet, looking for information about uranium and thorium geochemistry. I happened to find a web page posted by Dr. James Otton of the U.S. Geological Survey and sent the following question.

Can you suggest a book or article that can give me a good understanding of how uranium is concentrated in the earth's crust? I was recently corrected, thinking that uranium and thorium were subject to fractional crystallization just as the more abundant elements are.

Is there some way uranium can be preferentially concentrated in a magma body? How do water solutions concentrate uranium in veins that can be mined? I'm not interested in mining. I'm more interested in how different geochemical and geophysical processes affect radiometric dating strategies.

Otton’s reply came quickly.

"Uranium and thorium ARE strongly fractionated during magmatic processes and tend to be concentrated in the silicic/felsic part of a magma, hence granites and rhyolites tend to have a much higher average uranium and thorium concentration (3-5 ppm U) compared to basalts (<1 ppm U). Some granites in New Hampshire, Arizona, Washington State, Colorado, and Wyoming range from 10-30 ppm U. Rhyolites in Yellowstone N.P. average about 7 ppm U. Most genetic models for uranium deposits in sandstones in the U.S. require a granitic or silicic volcanic source rock to provide the uranium. Most of the uranium deposits in Wyoming are formed from uraniferous groundwaters derived from Precambrian granitic terranes (a terrane is a crustal block bounded by faults, whose geologic history is distinct from the histories of adjoining crustal blocks.)

"Uranium in the major uranium deposits in the San Juan basin of New Mexico is believed to have been derived from silicic volcanic ash from Jurassic island arcs at the edge of the continent. An excellent reference to hydrothermal uranium deposits and magmatic processes involving uranium is a book by Vladimir Ruzicka entitled Hydrothermal Uranium Deposits."

If a geologist dates the extruded magma using the U/Pb method, the material first out will date much older than the uranium-enriched magma that comes out last. Because it is the bottommost magma flow, geologists assume it is much older than subsequent flows. It is older, but only by hours or a few weeks. The lava beds at Steen's Mountain in Oregon show rapid change in magnetic orientation, as though the magnetic pole of the earth drastically and rapidly reoriented itself as the magma cooled, aligning the magnetic components of the lava as it cooled and solidified over many weeks. This shows that superposed lava flows are not necessarily separated by long ages

Dr. David Plaisted has helped me argue the case more effectively. He has an excellent web site, http://www.cs.unc.edu/~plaisted/ce/, which contains articles on many subjects. Also see his article How Old Is Humanity on this web site.

"Younging Up"--The Rest of the Story

Most geologists would say that radiometric dates of strata tend to become younger from the lower to the upper parts of the geologic column. Professor Kurt Wise refers to this trend as "younging up," but it might be an artifact of geochemical processes, basic assumptions made during the dating process, and reporting bias as a byproduct of evolutionary presuppositions. John Woodmorappe, author of Studies in Flood Geology and The Mythology of Modern Dating Methods, says that the "younging up" tendency has never been established. He means that, among other things,

1. There is no control over the number of dates obtained per stratigraphic interval;
2. There is no control for dates obtained per area of granitic crust;
3. Most discrepant results are not published, especially those which geologists view as "too old" and those which are the most severely deviant.

Woodmorappe recommends that until these matters are subject to a careful controlled experiment, we withhold judgement as to whether a "younging up" tendency exists [and, if so, is it strong enough to warrant a special explanation?].

In other words, we might be falling into the same trap as evolutionists, believing that there actually is a "younging up" trend in the geologic strata when no one has actually confirmed it scientifically. Geologists may have simply assumed it is true and repeat it as fact without ever having established it.

The influence of uniformitarian doctrine is probably at fault here. Ever since James Hutton and Charles Lyell produced their works on the geologic record over 150 years ago, geologists have accepted the axiom that present processes are the key to the past. This is the heart of the uniformitarian working model. The slow, gradual processes of the erosion and sedimentation operating today were essentially the same in the past. These processes produced the stratigraphic layers over millions of years.

Many, if not most, geologists no longer accept the uniformitarian doctrine. Now they say that over millions of years, catastrophic events, such as the asteroid bombardment that supposedly wiped out the dinosaurs, have periodically punctuated earth’s history. Such catastrophic events produced much of the stratigraphic record. Derek Ager was probably the most influential proponent of the new catastrophism among evolutionary geologists. In The New Catastrophism, he explained that he became a believer in catastrophism through his study of turbidites, which are rock formations produced by fast moving, underwater turbidity currents known to cover thousands of square miles from several feet to many hundreds of feet thick in only a few hours. Other geological sedimentary features, ranging from limestone to conglomerates and covering more than a million square miles, appear to have formed rapidly. Some formations span several continents, indicating that at one time those continents were possibly all part of the same land mass, Pangea.

We should expect that radiometric data will not properly reflect the time element, especially if the strata formed during the Flood, but also if past catastrophic events produced one or more geologic layers. Failure by previous isotope geologists to consider this when they derived dates correlated with index fossils, could misguide the researcher, causing him to make erroneous assumptions. This could produce false dates and a "younging up" trend.