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Geologic Time: The Scientific Evidence and the Fossil Record

Spectrum magazine, vol. 10, no. 1 (May 1979), pages 12-19.

© 2002 Spectrum/AAF. All rights reserved.

By P. E. Hare

Ed Hare, of the Carnegie Institution, Washington, D.C., has his doctorate from the California Institute of Technology. He has taught at Pacific Union College and is a former member of the Geoscience Research Institute.

The crucial battle in the present war the present war between science and scripture seems to be centered on the question of time. How much time is represented by the stratigraphic succession of rocks in the earth’s crust? Do the ages of fossil-bearing rocks extend back to 600 million years (Cambrian), or even back into the Precambrian as suggested by radioactive age dates? Or are most fossil-bearing rocks the products of recent catastrophe as advocated by "flood geologists"? This seems like a straightforward question that could be approached from a number of scientific disciplines. But it is obviously much more than a scientific question. Many scholars, including a number who have been trained in believe that the earth is only about 6,000 years old. Their belief is based not so much on scientific evidence as it is on an interpretation of "divinely inspired statements that limit the earth’s age to thousands of years. The obvious danger in this approach is to assume our interpretation of scriptural data as infallible, as did most Christians in the controversies of the sixteenth and seventeenth centuries. Equating inspiration and infallibility is a deadly error and is a trap that must be avoided as we seek to harmonize the works and words of God.

For those who believe that "true science is but an interpretation of the handwriting of God in the material world,"1 that nature and revelation shed light on each other,2 and that a correct understanding of both will prove them to be in harmony,"3 it is a serious matter to disregard either scientific or scriptural data. The committed Christian takes both scripture and science seriously, since he believes God to be the author of both. When problems of harmonizing occur, the natural impulse is to choose sides and dismiss the opposing side as in error or irrelevant. Most fundamentalist Christians—including many of the Seventh-day Adventist scientific community—reject the scientific evidence for an old earth, feeling that an old earth is not compatible with scripture. They stand in opposition to the group (most of the non-Christians in scientific disciplines) who reject the relevancy of scripture and feel only the scientific evidence can be trusted.

Some Christians compromise by separating the inorganic earth from the fossils and accepting the scientific evidence for the age of [13] the inorganic materials. They suggest that the present crust of the earth was formed at "the time of the flood" by reworking the old inorganic rocks and incorporating fossils from various ecological zones into various layers. Reworking the older rocks, they argue, has resulted in a series of apparent ages, as the radioactive clocks were contaminated or only partially reset.

Still others, attempting to find harmony between scripture and science, consider both sources to be essentially correct as a starting point at harmonization. Let them both speak for themselves, they argue. If the interpretation of the evidence for an old earth is correct, there must be a problem, not with scripture but in our interpretation of scripture. It should be possible to harmonize most, if not all, of the existing problems between science and scripture by allowing each source to shed light on the other. This approach is not the easy way out. An individual may find it a real struggle to modify concepts, scientific or scriptural, he has held for many years. It is not easy to evaluate data, especially if they are not in one’s area of training. To determine what the data of science may really say as opposed to someone’s interpretation of the data is just as important as approaching scripture and deciding what God is saying through the inspired human agencies. The prophets of God were inspired, but not infallible, as the story of the disobedient prophet in 1 Kings 13 so dramatically records.

Clearly, many scriptural passages must be interpreted in the context of the time in which they were written. When Joshua commanded the sun, "Stand thou still" (Joshua 10:12), he was speaking in the framework of his scientific concepts, not twentieth-century concepts. There was no thought of settling a future scientific debate between the followers of Copernicus and the followers of Ptolemy. The reformer Martin Luther used Joshua’s statement to "prove" that the Bible taught the earth was fixed and it was the sun that moved around the earth!4 The astronomical evidence is so obvious to the trained mind of the twentieth century (common-sense observations still suggest that the sun moves around the earth) that we interpret Joshua’s statement in its historical context to achieve a harmony between scripture and science.

Many feel that this method of harmonization is not valid for geological data on the age of the earth and the age of fossil-bearing rocks. It is felt that if much more than 6,000 years is allowed for the age of the earth this will prove evolution to be true. Actually, the probability for the spontaneous generation of a living cell is still infinitely small even if 4.5 billion years were allowed instead of 6,000.5 The evolutionist who rejects God and the supernatural must believe in spontaneous generation in one form or another. Pasteur in the nineteenth century presumably discredited this theory and put it to rest; but in recent decades the theory has rebounded and is again a respectable scientific concept to many scientists.6 To believe in the origin of living organisms from the spontaneous chance organization of inorganic matter requires a faith not unlike that required of the Christian to believe "In the beginning, God created. . . ." Science may never be able to provide data to answer the great questions of origin. How and when was the universe created? How and when was life created? Faith apparently will always be necessary whether in science or in scriptural understanding.

To many scientists, the evidence for an age of billions of years for the earth is convincing. Consider a brief geological case study of Crater Lake in Oregon. A spectacular series of volcanic explosions of ash, pumice and other volcanic debris, followed by the collapse of the top of an ancestral peak into a craterlike r depression (called a caldera) formed what we now know as Crater Lake. By piecing evidence together from a number of geographical areas and different disciplines, scientists have reconstructed the past events in detail and have suggested that Mount Mazama lost its top about 6,500 years ago at a time when the wind was blowing from the southwest and glaciers still covered much of the upper reaches of Mount Mazama.

Geological evidences of past events are much like the clues found at the scene of a crime. Each clue needs to be evaluated and [14] interpreted within a time sequence. Most geological evidence involves the sequence or succession of past events. An obvious but important concept is that in a series of superimposed, undisturbed sedimentary layers the lower layers are older than the upper layers. Another is that volcanic ash from a volcanic explosion can be carried hundreds of miles from its source and be deposited in the ocean, lakes, peat bogs or permanent ice sheets nearly simultaneously, forming a marker ash bed that can be used for correlating events prior to and subsequent to the volcanic explosion. "Tephrochronology" is the term applied to geologic age-dating and correlation by means of volcanic ash. (Tephra is the general term for ejected volcanic material.)

Consider some of the geologic evidence for the history of Crater Lake. The casual visitor to Crater Lake is impressed by its deep blue color, size (approximately five miles in diameter) and depth (about 2,000 feet). The steepness of the rim around the shore indicates an unusual setting for a lake, since no rivers can be seen entering or leaving the lake. The rugged, uneven surface of the rim is an important clue to the possible ancestral mountain. Glacial evidence in the form of U-shaped notches in the rim, polished bed-rock and moraines at the foot of the U-shaped valleys suggest extensive glaciation in the past. The U-shaped notches in the rim resulted when the upper part of the peak with its glaciers and upper parts of the U-shaped valleys collapsed into the caldera, leaving only the lower part of the glacial valleys intact. The obvious conclusion is that in order to support such extensive glaciers there was a high elevation source for snow and ice accumulation; hence, the reconstruction of Mount Mazama to 12,000 feet elevation or more.

The direction of the wind when Mount Mazama exploded is known, of course, from the distribution of airborne pumice and ash. Deposits of tephra extend toward the northeast and diminish in particle size and thickness with distance from Crater Lake. Ash from the explosion blanketed thousands of square miles and has been incorporated into he sedimentary record of peat bogs and lakes throughout the northwest.7 The layers of Mount Mazama ash provide useful horizon markers for relating other sedimentary structures such as pollen profiles. Recognition and identification of ash layers are aided by chemical and petrologic analysis of the particles. Different volcanic sources—and successive ashes from the same source—have distinctive chemical "fingerprints." Fission track dating of glass "shards" in the ash is also useful in correlation and identification of ash layers.

When Mount Mazama exploded, the tephra, of course, was hot. The finer ash particles remained airborne and eventually cooled; but the larger ash and pumice fragments fell to the ground in an incandescent avalanche. The fiery cloud charred and buried not only trees growing around Mount Mazama but some up to 35 miles away! Some of these charred trees were discovered during the construction of a road cut and sent to a radiocarbon laboratory for C-14 dating. The analyses of several specimens in different laboratories yielded radiocarbon dates of about 6,500 + 200 years B.P. (before present) as the time when these trees were killed and buried and Crater Lake was born.8

Regardless of whether or not a date of about 6,500 years ago is accepted as a reasonably accurate estimate of the time since Mount Mazama exploded, it must be realized that this event is just one of the most recent geological events that has occurred in the area. Before the explosion, a mountain existed that was high enough to sustain major glacial activity for some period of time. Three episodes of glaciation are recognized with glacial debris alternating with volcanic rocks.9 Evidence also suggests ice thickness to 1,000 feet and glaciers ten or more miles in length. The building of Mount Mazama to an elevation of 12,000 feet or more (8,000 feet above the surrounding plateau) did not occur overnight but apparently built up over a period of time by intermittent activity with ejection of ash, pumice and other debris alternating with outpourings of lava. The postmortem anatomical record of these episodes in the building of [15] Mount Mazama can be clearly seen today in the steeply dipping layers of rock forming the rim around Crater Lake.

The most interesting information relating the demise of Mount Mazama with other geological events comes from the layer of ash that blanketed much of Oregon, Washington and Idaho as well as parts of Montana, British Columbia and Alberta. This time-stratigraphic marker is found preserved in numerous lake sediment cores and peat bog sections throughout the Northwest. In some deposits, other volcanic ash layers are found in addition to the Mazama ash layer.

Ash falls older than Mazama ash are abundant and widespread. One particularly widespread ash deposit originated from Glacier Peak and when found in the same lake sediment core or peat bog section is found considerably below the Mazama ash, indicating an earlier date for the Glacier Peak ash. Stratigraphic estimates based on average sediment accumulation rates suggest Glacier Peak ash to be roughly twice as old as the Mazama ash.10 Radiocarbon dates confirm this estimate and indicate that the Glacier Peak ash is about 12,000 years old.

As spectacular and awesome as active volcanoes are, they do not represent the ultimate in volcanic activity. The most extensive volcanic areas often do not even have true volcanic mountains. Fantastic amounts of very fluid lava have poured out through great fissures and spread out over the earth’s surface for thousands of square miles. Known to geologists as plateau or flood basalts, individual lava flows commonly range from 21 to 100 feet in thickness and may exceed 5,000 feet of total accumulation.

Over 200,000 square miles of the states of Oregon, Washington and Idaho are covered by plateau basalts, the Columbia River Basalt group as they are referred to in the scientific literature.

The Columbia and Snake Rivers have cut spectacular channels and canyons into the Columbia River basalts, exposing in the canyon walls the history of successive outpourings of lava. Frequently, individual flows show evidences of weathering and erosion, indicating again the lapse of time and the intermittent nature of volcanic activity. Fossil evidence preserved in soil zones between lava flows suggests that a wide variety of plants and animals existed locally during the quiet periods between the outpourings of molten rock. Molds of upright trees several Feet in diameter appear to be in position of growth with even the impressions of the tree bark preserved in the lava molds. In at least one case, the bloated body of a rhinoceros left an almost perfect lava mold!11

The enormous volume of lavas that makes up the plateau basalts of the Columbia River Basalt Group is considerably older than Mazama or Glacier Peak ash. In places, nearly 2,000 feet of younger sediments (Mascall and Rattlesnake formations) overlie the Columbia River Basalt Group, and lake and peat bog sediments containing Mazama and Glacial Peak ash layers, in turn, overlie the eroded (glacially eroded in some places) surfaces of those formations.12

Below (and therefore older than) the extensive lavas of the Columbia River Basalt Group are the John Day and Clarno formations, which contain some of the richest vertebrate and plant fossil beds in the Northwest. Volcanic explosive material makes up a large part of the thousands of vertical feet of strata represented. The flora and fauna represented by fossils show a far different panorama of Life than is found anywhere near the area today. Fossil evidence points toward a mild temperate and wet environment in contrast to the semiarid, continental-type climate prevailing today. Preservation of delicate plant structures is so nearly perfect that it seems unlikely that fossil remains were transported any great distance.

Still older rocks of Mesozoic and Paleozoic age are found stratigraphically below the Clarno formation.12 Some of the formations [16] are similar to rock types and fossil assemblages found in the cliffs of the Grand Canyon far to the south and east. All of these stratigraphic units can be arranged in order from youngest to oldest based strictly on the principle that in a series of superimposed sedimentary beds the top layer is the youngest and the bottom layer is the oldest. Nowhere, of course, do you find all the units intact at any one locality. Erosion has removed some units from some places and redeposited them as younger rock layers. Nevertheless, by careful mapping of various units and making use of drill core data, it is possible to arrange the sequence of geologic events (erosion and deposition) that has produced the geologic column. This has been the principal work of geologists over the last century and has made possible the production of geologic maps and the correlation of stratigraphic units over widely separated areas.

If geologic science is on the right track and the geologic column does represent a sequence of events over the vast span of time, how can the scriptural record be harmonized with this evidence? Let’s explore some possible approaches.13 The scriptures are concerned primarily with the creation of man and the subsequent history of civilization. In the geologic record, human fossils are found only in the uppermost stratigraphic layers, the Pleistocene. This would seem to indicate that the geologic record of pre-Pleistocene rocks took place before the time recorded in scripture, concerning which scripture is silent.

What about the flood? Where does it fit into the geologic record? The scriptural account suggests that man had populated a sizable geographical area of the earth. If we use he principle of letting each record shed light on the other, we would look for geological evidences of the flood within the Pleistocene. There would seem to be several possibilities, including the worldwide catastrophic rise in sea level during the melting of the continental ice accumulations. It follows that if this approach is correct, then most of the sedimentary rocks of the geologic column are not the result of the flood. Along with most scientists of the eighteenth century, George McCready Price in his flood model assigned virtually all the stratified rocks to the flood. The question of time is crucial. How much time is represented by the sequence of rocks in the geologic column? Age-dating methods suggest billions of years. Flood geologists believe most of the sedimentary rocks were formed by the flood in a short span of time. If flood geology is on the right track, then it should be possible to show that the various age-dating methods are totally in error. This seems unlikely in view of the fact that estimates based on realistic sedimentation rates of carbonate rocks—as well as other sediment types—are in general agreement with results from other age-dating techniques.

It is interesting to note that the same age-dating tools (radiocarbon) and stratigraphic principles used in geology are frequently used in archeology to date material and to determine the relative succession of occupational levels to substantiate Bible history. The Dead Sea Scrolls have a radiocarbon date of about 2,000 years and show that the much later manuscripts upon which our present Bible translations are based have changed very little from these manuscripts dating to 100 B.C. Radiocarbon dating was used to show these manuscripts were not just recent fakes. A quotation from Time shows an example of what happens when scientific methods are applied to Biblical archaeological problems:

Christians revere the Bible as a treasury of divine revelation; skeptics regard it as an unreliable collection of fable and folklore. Over the past century a host of scientists—archaeologists, geologists, astronomers, botanists—have added a third perspective. Beneath the barren plains and foothills of the ancient Biblical country, they [17] have made discoveries revealing that whatever else it may be the Bible is a remarkably faithful chronicle of history.14