Science in Christian Perspective

Divisions of Geologic Periods

From: JASA 19 (June 1967): 60-61.

The comments by Dr. J. N. Moore (March 1966 p.32) caused me to review once more the reference cited by Morris and Whitcomb (The Genesis Flood, p. 211) in light of the comments made earlier by Dr. Wayne Ault (March 1964, p. 30). Morris and Whitcomb refer to an address by Dr. Edmund Spieker as part of a Distinguished Lecture Series given at many universities throughout the country. The lectures were sponsored by the American Association of Petroleum Geologists to stimulate discussion on various phases of geology. It was their purpose to point up a problem which has long been recognized in the formation of the geologic column. This is the matter of the boundaries between the divisions of the geologic time table.

When first developed in the 19th century, the divisions between the geologic periods and eras were arbitrarily placed where there were thought to have been great tectonic (mountain building) movements. Thus it was said that the Appalachian Revolution marked the end of the Paleozoic, the Laramide Revolution the end of the Mesozoic, etc. As Spieker points out, this has long been known to be an unworkable concept for it is very difficult to determine the actual time of tectonics and no orogeny is worldwide. Spieker urges geologists to recognize, therefore, that the geologic column cannot be correlated exactly worldwide. He further points up the fact that mountain building has occurred through billions of years of geologic time and many orogenies are recorded in the rocks.

If Morris and Whitcomb had chosen to use Spieker's article in its entirety, they would have had one of the strongest arguments against the Noahic Flood's having formed all the geologic strata.

In pointing out the difficulties involved in placing orogenies stratigraphically, Spieker does not question the observed sequence of strata which have been laid down during the various geologic ages. He stresses the importance of correlation of the various outcrops to build up a composite geologic column. In correlating, the geologist determines that certain layers in one outcrop are the same as layers in another outcrop not immediately adjacent to the first. Thus, if four layers of outcrop A are observed and it can be shown that the top layer is the same as the bottom layer of outcrop B, then a composite column incorporating the layers in both outcrops can be made. It is from this type of careful field work that the total geologic column of about 500,000 feet of strata has been determined.

If these were all laid down by the Noahic Flood, we should not have the evidences of numerous orogenies in the column; many times layers were deposited, formed into rock by cementation or compression, raised up to make mountains, then eroded to deposit sediment in another basin.

In contrast to Morris and Whitcomb's observation (p. 209), "The geologic time scale is an extremely fragile foundation on which a tremendous and unwieldly superstructure of interpretation has been erected," Spieker (p. 1812) says, "I do not propose any changes in the time scale. Past experience shows, for one thing, that it would not do any good. But, more important, the scale we have is just as good as any other; let us merely use it in full apprehension of the things I have been trying to bring out. Let us try by all means to think intelligently about it, laboring to discover the real significance of its boundaries and making them conform to nature as far as possible but realizing that in the end correlation is far more important than subdivision and that our whole picture of boundaries may be illusory; above all improving the means in paleontology, stratigraphy, and structural geology as best we can to deal with its extremely difficult problems, but never allowing ourselves to see in it features that are not justified by all the pertinent and acceptable facts. Let us not forget that our time scale is a distributive generalization and so can not stand on any group of facts for any time or place."

Spieker's argument is not against the time table and an orderly sequence of layers laid down over a long period of time, but points out, as long recognized by geologists, that the boundaries between the di%isions cannot be worldwide and are difficult to pinpoint at most localities.