RAPID BURIAL OF ORGANISMS AND SEDIMENTARY STRUCTURES
TO BE FOSSILIZED
A surprising number of evangelical scientists and theologians tend to accept the much-publicized assertions of Morris and Whitcomb that rapid burial (such as in a flood) is absolutely necessary for the production of fossils, and that practically all fossils found in the earth's strata are the result of the Biblical Flood (Myers, 1984, pp. 44-45, 55; compare Morris, 1974, p. 100). Most geologists agree that rapid burial usually enhances fossilization, and that the formation of some kinds of fossils is dependent upon it. But we need to realize that, (a) there are many places on earth where large numbers of fossils are now being formed gradually, and that (b) we now know of many geologic events which occurred in the past, rapidlycovering relatively large areas of the sea floor with sediments.
First, we will consider item (a), places where fossils are now being formed gradually. During the past 25 years many research projects carried out on coral reefs in various parts of the world's oceans have shown that gradual fossilization takes place both within the hard parts of the reef and in the accumulations of sediment around the base of the growing masses of coral. A piece of coral rock broken off the outer part of an actively growing reef has skeletons of living corals and calcareous algae on its surface. But sawing the piece in two reveals that, even at a few centimeters below the surface, fossilization processes are well under way. See Friedman and Sanders (1978, pp. 155-56) for a description and photomicrographs of some of the progressive stages of this fossilization. The reef rock is often found to be in a completely cemented condition, with the skeletal fragments fully fossilized, at 60 centimeters below the surface of the living layer of reef growth. In a detailed study of fossilization in Bermuda patch reefs, Scoffin (1972, p. 1281) found that, in the accumulations of loose sediment around the bases of the living clumps of coral, fossilization processes frequently begin at a depth of about 30 centimeters. In such a sediment mass the cementation process contributes to the fossilization, and also binds the shells of many small marine organisms present in the sediment, thus forming a kind of rock which shows a high percentage of small skeletal units throughout. Whether or not this cementation will progress to the point of eventually forming hard rock depends on the amount of water currents forcing water through the pores of the sediment mass.
A great number of studies of drilling cores taken from ancient, buried coral reefs in the oil fields of the world have shown that an appreciable number of the reef organisms were fossilized in growth position, having then been covered over by addition al layers of growth of corals, algae, and other carbonate-secreting organisms (Langton and Chin, 1968, pp. 1925, 1927, 1930-42). So here are great bodies of highly fossiliferous rock, sometimes extending over several square miles and to a thickness of hundreds of feet, which contain immense numbers of fossils which were formed gradually as the reefs increased in size and thickness. This should also serve to remind us that the ancient, carbonate hardground layers discussed in a previous section of this book contain an abundance of fossils which were formed on the sea floor and eroded extensively before additional layers were added.
Now we will examine the second item, (b), mentioned in the first paragraph of this chapter. This has to do with known processes of rapid burial which have been going on throughout much of geologic history (at least from the Cambrian to the present).
Twenty-five years ago, when Morris and Whitcomb set out to revive the old "Flood geology" view, geologists and paleontologists did not have very much evidence for ways by which the animal and plant fossils (except microfossils) could have been buried rapidly. But with the great—really enormous—increase in sea-floor and continental-shelf research since that time, several means of rapid burial have been discovered, and a large number of cases of it have been identified in both recent and ancient strata by sedimen tary geologists. Unfortunately Morris and his associates have not been in touch with the geologic profession enough to know that these discoveries were being made. So they have continued to assert that the oniy way that the animals and plants could have been buried was by a worldwide major flood.
2. Principles Having to Do with Burials
In order to understand why it is incorrect to say that practically all burials had to be accomplished by a single flood, we must first recognize that nearly allof the animals which were fossilized lived in marine habitats, and that most of those were shell-producing invertebrates. The depositional events which can effectively bury such animals occur mainly in underwater environments. Such events can occur very easily and on very gentle slopes of sea floors, because of the buoyancy of the water. The water is much more dense than air, so it has a strong supporting effect upon the loose sediments and organisms which normally lie on the floors of bodies of water. Various kinds of sediments flows,* such as mud flows and debris flows,* often occur on sea floors, both on the continental shelves and farther out to sea.1 There is also much evidence that such movements of sediment occurred on the shallow bottoms of the ancient inland seas in North America and other continents. This activity apparently provided a means by which bottom-dwelling organisms were buried rapidly from time to time when earthquakes or heavy storms triggered the start of sediment slides and sediment flows.
Sediments slides and flows have also been observed to occur on land. These flows are often continuations of landslides which have begun on steeper slopes during heavy rains. In this kind of situation the rains supply enough water that parts of the slide will become a debris flow, with the particles supported by water and the additional density contributed by mud particles in the water. In such a case the debris flow may continue for a relatively long distance on down to where the slope is very gentle, and vertebrates as well as invertebrates are usually trapped and buried in it.
3. Some Examples of Known, Large Sediment Flows
In submarine environments sediment flows occur easily, and on slopes as gentle as one degree (Cook, 1977, p. 372; Molnia, et al., 1977; and Cook and Mullins, 1983). Once the movement begins, the fine particles which become suspended effectively increase the density and viscosity of the water mixture, so that coarser materials can be suspended and moved also (Friedman and Sanders, 1978, p. 205). Such a flow frequently gains a rapid momentum and continues for several miles out to sea, covering great numbers of marine organisms. The fact that earthquakes were frequent and often intense in earlier times, especially during the orogenies,* makes it almost certain that such burial events were more frequent than now. Cook (1977, p. 372) states that some modern sediment flows off the coasts of the U.S., Alaska, Chile, and elsewhere have "occurred after earthquake shocks of magnitudes ranging from 6.7 to 8.5," and that the amount of sediment moved in each of the flows has ranged from 300,000 cubic meters up to 70 x 109 cubic meters. (A cubic mile of sediment contains 4 x 109 cubic meters.) The formation of sediment-flow deposits frequently occurs both in carbonate sediment environments and in areas where the slopes are covered by terrigenous sediments (Cook and Mullins, 1983). A detailed study of very recent carbonate debris flow and turbidity flow deposits in the Bahamas was made by Crevello and Schlager (1980). They found that approximately 25% of the upper 7 meters of sediment lying on the lower slope of Exuma Sound was made up of these types of deposits (1980, p. 109).
Thus, there is no doubt about the ability of sediment flows to bury large numbers of marine animals and accumulated shells for their later fossilization. Lists and descriptions of a large number of known, submarine sediment slides and flows can be found in the following works: Embly and Jacobi (1978), Kelts and Arthur (1981), Saxov and Nieuwenhuis (1982) and Cook and Mullins (1983). The article by Embly and Jacobi describes mainly slides and flows which occurred on slopes of 3 degrees or less, and in water depths of greater than 200 meters (p. 207).
In areas inland, on the continents, where there are great, thick sequences of sedimentary strata—as in most of the United States—stratigraphers and sedimentologists have observed the remains (deposits) of many ancient sediment flows which occurred while the areas were under water. These flow areas can be identified by the shape of the sediment mass, a sharply defined base, and the thinning out of the mass at its extremities. The gradation of particle size in various parts of the body of sediment, due to difference in the velocity of movement and differences in density in different areas of the flow, also aid in identification. So, we do have a good record of sediment-flow burial events in the sedimentary strata inland, on the continents.
Also, in the inland areas, the sedimentary formations contain many small bodies of silt, sand, and sometimes gravel. (Some of them are known as "lenses" of sediment, due to their lens-like shape.) Some of these bodies of sediment show definite evidence of having been accumulated rapidly by the direct action of storms on the seacoasts and often resemble sediment masses which are piled up by present-day hurricanes. Many such storm deposits are found in ancient sedimentary strata, and are described in the research reports of sedimentary geology—including large numbers of fossils which are found in the storm sediments (Kreisa, 1981).
The failure of creationist authors to recognize and disseminate the data concerning these methods by which rapid burial takes place has given most creationists the erroneous idea that natural processes could not have formed the fossil deposits (see Myers, 1984, pp. 54-55). The belief that the majority of these deposits were formed by the Biblical Flood, which we recognize as being relatively recent, is especially untenable when we consider the mature state of most of the fossils found on the continents. Nearly all of these show not only the evidences for having been completely fossilized and encased in cemented sediment, but also the marks of having been further altered chemically and physically over long periods of time. In many formations we even find fossils which have been "reworked." That is, they are fragments which were eroded out of older strata and then incorporated into new rock layers.
Within the past few years some young-earth creationist authors have learned that certain sediment flows have been observed in the earth's strata, and have hypothesized that they took place during the Biblical Flood. It islikely that sediment slides and flows occurred during the Biblical Flood, and it is possible that some of these may have been preserved in near-surface formations on land. But there is no conceivable way that such masses of soft sediments could have retained their form and identityif they were rapidly covered by the weight of thousands of feet of sedimentary deposit and subjected to the tectonic movements which are thought to have accompanied the Flood. We must realize that these sediment-flow deposits are often found at more than one level in a given sedimentary column, the lower ones having been buried very deeply. This is illustrated in the strata of the Devonian, Catskill clastic wedge deposits of Pennsylvania and New York (Thompson and Sevon, 1982, pp. 23-31, 102-04, 115-16).
As we pointed out in the section on significances of the great thicknesses of sedimentary sequences found in the Appalachians, uncemented layers of mud and other sediments amalgamate into a confused mass if they are subjected to great weight, and to disturbing tectonic events. Yet we find the neatly-preserved remains of ancient debris flows* deep in the Appalachian and other strata (Cook and Mullins, 1983, pp. 562-64), still showing a striking resemblance to the flows which have occurred in recent times and have been found on or near the surface of the sea floor—though much more mature and cemented than the latter flows. (Compare Cook and Mullins, 1983, pp. 567-69.)
4. Sediment Flows as Agents of Terrestrial Burial
Concerning the burial of terrestrial animals such as amphibians, reptiles, and mammals, one has only to recall the fact that sediment flows have been observed to occur on land during local floods, and that some of these have left rather thick and extensive deposits which contain many kinds of objects and animal and plant bodies. From this it is evident that most of the terrestrial-type fossils found in the earth's strata could have been buried by this same means. (The remains of very severe local floods in ancient strata have been recognized in several parts of North America and other continents for most of this century.) On the other hand, we do not deny the possibility that some near-surface "fossil-graveyards" may have been formed by the Biblical Flood. The frozen mammoths of Siberia are an example of this possibility.
But it is false logic to conclude that because someterrestrial-type fossils may be the result of burials which occurred during the Flood, then most or all terrestrial fossils originated in that manner. Neglect of the well-known principles of rock lithification which we gave in Chapter 3 has caused many creationists to go astray in this respect. They as well as the present writer agree that the Biblical Flood occurred less than one hundred thousand years ago; so we have to realize that fossils which are found embedded in hard, fully-cemented sedimentary rock were entombed in that rock long before the Flood—unless the rock is the one distinctive type of limestone which can become cemented rapidly, namely beachrock.
5. Fossils Which Were Buried in the Diatom aceous-Earth Deposits at Lompoc, California
The well-known diatomaceous sediment deposits at Lompoc have been found to contain many macrofossils, such as marine fishes and even a whale. (Such fossils are frequently uncovered there by mining operations, since the "diatomaceous earth" has several commercial uses.) From the positions in which the animals were trapped in the diatomaceous sediment and from the excellent state of their preservation, we conclude that these fossils are the result of a rapid burial event. Before the discovery of rapid, submarine sediment flows the circumstances under which these animals were buried was very much a mystery. Followers of "Flood Geology" sometimes made the claim that the Biblical Flood was the only event that ever occurred on earth that could have caused these burials. However, this was always a very unsatisfactory hypothesis, because the questions of where this great, thick mass of diatom shells came from still remained.
Diatoms are microscopic-size plants which live either a floating (planktonic) existence near the surface of the oceans and of other bodies of water, or live on the bottom if the water is not so deep as to reduce the light too much for their photo synthesis. Diatoms are actually one group of the algae, and have the distinctive ability to secrete a thin, very durable, silicon dioxide shell ("frustule") in which to live. When they die, the protoplasm disintegrates and the shell sinks to the bottom of the ocean. In areas where diatoms grow in abundance, a few centimeters of diatom-shell sediment can accumulate on the sea floor in one thousand years. There is obviously no way that the waters of a great flood could selectlarge quantities of diatom shells from the ocean surface, or from the diatom deposits on the ocean floors, and safely transport them in relatively pure form to the California area, to produce diatom beds which are several hundreds of feet thick. And we are not at liberty to postulate that God assembled all those multiplied trillions of microshells to the California coast by a special miracle, and caused them to suddenly drop out of the surging waters in a way that would confuse, smother, and bury the animals before they could escape. (Remember that most of these diatoms are so small that at least 400 diameters magnification is required for seeing them under the microscope.) So it surely seems far better to recognize the natural world of microorganisms, and their growth and deposition, for what they are—a part of God's wonderful, orderly creation.
Because of the long periods of time which diatoms have existed in the oceans, the shells have been able to accumulate to great thicknesses on some parts of the ocean floors. Drillings made by the Deep Sea Drilling Project crews have located beds of diatom sediment hundreds of feet thick in several areas of the world. For example, at 53° 32' south latitude, south of western Australia, the drillings of Cruise no. 28 recovered approximately 260 feet of diatom sediment cores from the hole drilled at Site 265. Nearly all of this sediment contained 80% to 90% diatom shells (Hayes, Frakes, et al., 1975, pp. 60-65). Since the drilling crew recovered cores of only about 25% of the total thickness of diatomaceous sediments they drilled, the thickness of diatom sediments there is much more than 260 feet. The cores which were recovered were from fairly regular intervals from the surface of the sea floor down to a depth of 370 meters. Drilling samples were taken continuously from the intervals which were not cored, and it was found that diatom shells make up a high percentage of almost all of the entire sediment column drilled (Hayes, Frakes, et al., 1975, pp. 51-52, 60-65). Then at Site 266, three degrees further south, they drilled through 148 meters of practically continuous diatom ooze of similar diatom content to that of Site 265, and approximately 50% of the 148 meters were recovered as cores (Hayes, Frakes, et al., 1975, pp 82-84, 92-97).
Some other drilling sites where the Deep Sea Drilling Project
thick deposits of sediments containing high percentages of diatoms are
Because of these facts it is logical to conclude that the Lompoc diatom beds were deposited naturally on the ocean floor, and that sometime before the period of tectonic activity which finally raised them to an elevation above sea level, the earthquakes in that area triggered at least one large sediment slide and flow which overwhelmed and buried the animals that were down-slope from where the slide began. As pointed out in the early parts of this section on rapid burial, we now know of large sediment flows in various parts of the world which apparently had all of the characteristics necessary for overwhelming and burying both swift and large marine animals. Henry Morris' s statements concerning the fossilization of so many fish in the diatomaceous sediments near Lompoc, California, shows how desperately he needs to acquire a knowledge of natural burial events (Morris, 1974, pp. 97-98).
6. The Burial of Non-livin, Ephemeral Sedimentary Structures
Before ending this section we should refer to the burial and preservation of sedimentary structures, such as ripple marks, cross bedding, sole marks, and desiccation cracks. Myers (1984, p. 43) emphasizes the claim, made by Morris and others, that such ephemeral structures could not have been preserved in the sedimentary strata except by a worldwide flood. This belief is of course due to a lack of knowledge of the many and frequent burial events during geologic history to which we have been referring. The evidence of these events is seen at manylevels in the strata of the rock systems which are present in local stratigraphic columns.
Sediment slides and flows, and storms on the coasts, are very capable of burying ripple marks and other sedimentary structures intact. Why then should anyone think that a great flood would be necessary for burying the results of wave and current actions on the sea floor at various levels in a sedimentary column? It is much more likely that normal burial events such as mud flows or storm deposits could effectively bury them than could a great convulsive flood such as Morris visualizes. The latter would surely be far more likely to destroy such ephemeral structures than to cover and preserve them.
1Debris flows and mud flows are types of sediment movement classified under the general heading "sediment gravity flows" (called merely "sediment flows" in this book). In debris and mud flows the density of the mixture of slurry is greatly increased because of the suspended particles. Another common type of sediment gravity flow is the "turbidity current flow," in which the sediment particles are supported mainly by the turbulent water, without major dependence on increased density of the fluid. Turbidity current flows usually produce sediment beds which are graded ("graded bedding"), whereas debris flow deposits are usually not well sorted. Sediment flows are not to be confused with simple, submarine slides—though debris flows often develop within and simultaneous with a submarine slide (Embly and Jacobi, 1978, pp. 205-11). See Tucker (1981, pp. 72-74) for a brief but good treatment of sediment flow types.
Since a high percentage of marine fossil beds contain many sizes and
shapes of shells and other skeletal parts, this appears to indicate
most of the rapidly-buried fossil deposits were buried by debris flows,
submarine slides, and storm-produced currents, rather than by turbidity
flows. If they had been buried by turbidity current flows, the fossils
would have been sorted according to size and density.