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Warren H. Johns
Graduate Student in Paleontology
Michigan State University, East Lansing, Michigan
Instructor in Religion
Columbia Union College, Takoma Park, Maryland
Origins 4(2):76-92 (1977).
Related page | IN A FEW WORDS |
The discovery of tektites in situ in recent soil horizons of southeast Australia, which are dated to 5000-6000 radiocarbon years, and the finding of corresponding microtektites in deep-sea deposits present some implications that challenge virtually every dating method applied to oceanic sediments.
Small, glassy objects in a variety of shapes have been found
scattered all across the surface of Australia and southeast Asia. Known as tektites, they
were first thought to have originated from outside the earth's atmosphere because of their
aerodynamically sculptured surface. Though much of their surface patterns are strikingly
similar to the surficial etchings on meteorites, yet the chemical composition of tektites
is quite different. Having only a trace of nickel as opposed to meteorites, they are
especially rich in silica (SiO2) and rarely are composed of less than 70% SiO2.
Thus tektites are not the waste products from meteorite showers.
On the basis of data on samples collected by five Apollo missions to the moon it is generally conceded that tektites were not formed from a shower of molten material ("moon drops") propelled toward the earth as a result of meteorite impacts on the lunar surface. Rather, it is now believed that they have originated from gigantic meteorite impacts on the earth itself (1). It appears that drops of molten material were projected into a low orbit and then re-entered the atmosphere at high speed, finally resting over a wide area known as a strewnfield. Artificial tektites of the same chemical composition as Australian tektites (australites) have been fashioned at air speeds of 17,000 m.p.h. in a wind tunnel at the Smithsonian Institute. To the untrained eye the end product is indistinguishable from natural tektites. Tektites from the Ivory Coast strewnfield have a chemical composition very similar to (if not identical with) the altered rocks of nearby Lake Bosumtwi, which has the main criteria of a meteorite impact site (2). Recently a probable meteorite impact site, Elgygytgyn Crater, was identified from satellite photos and is now proposed as the source for australites (3). The australite strewnfield is pie shaped and the apex points in the direction of Elgygytgyn in northeastern Siberia.
Australites have been dated concordantly at 700,000 years by two radiometric dating methods fission track and potassium-argon (K-Ar). This represents a major challenge to conservative Christians wishing to hold to a short Biblical chronology. But these 700,000 year radiometric ages are now under question by the use of another radiometric method, radiocarbon dating. In the 1960's two independent teams of investigators (4, 5) located australites in situ (see ORIGINS 3:85-96). Since the publication of their findings, a third team working independently of the others has reached essentially the same conclusion: that the time of infall for the australites should be in terms of a few thousand years instead of the generally acknowledged radiometric age of 700,000 years (6). These authors suggest an infall age of 6500 years based on a C14 date of 7300 years for wood fragments in the soil into which australites have fallen.
These conclusions place geologists and geochemists in a quandary. For those who have made first-hand field observations of australites, the evidence is in favor of a geologically young age, whereas those who work with them in the laboratory are convinced that the time when the tektites fell is the time of their last melting when the radiometric clock was re-set approximately 700,000 years ago (7). According to one way of solving the dilemma, the older age represents their actual age of formation somewhere in space and the younger age represents their terrestrial age. This hypothesis has been ruled out by the fact that no cosmic ray tracks have been detected in tektites, as in meteorites; thus limiting their hypothetical journey in the solar system to less than 300 years (8).
Another solution is to suggest that approximately 700,000 years ago the australites landed elsewhere than their present location and were subsequently washed into place as part of transported sediments a few thousand years ago. After reporting C14 ages of 5700 and 5350 years immediately adjacent to an australite, Gill notes that, if they were transported, neither the tektites nor the buckshot gravel which are always associated together at Port Campbell, Australia, "could have come far and both must have come gently because the edges are sharp on the australites, and the buckshot is not polished" (9). In a later publication Gill reaches the same conclusion: "The good preservation of the Port Campbell australites is against long residence in the soil, or long transport from one formation to another" (5).
More recently an author in commenting on Gill's conclusions notes that if the tektites were not transported, then the K-Ar age is under suspicion:
The Port Campbell australites as a geographical group are all astonishingly fresh and undegraded by terrestrial processes, as far as is known, and there seems little possibility that more than one shower is represented at Port Campbell. Hence, it is very difficult to accept Gill and Baker's conclusions, unless the K/Ar age date means something else than is commonly believed (10).
A 1976 study by a tektite expert confirms the fact that the dilemma has not yet been solved:
The papers of Gill and of Lovering et al. supply clear evidence that tektites are found on top of recent Australian soils whose ages, as given by carbon dating, are less than 20,000 years. The evidence is strong that they did not reach this position by reworking from older sediments at a higher elevation.¼ For example, a Czechoslovakian study shows that stream erosion will reduce glass objects of roughly tektitic character to about one-ninetieth of the original mass at a distance of 40 km downstream (11).
It is noted that in Lovering's study the nearest possible source for
the tektites would be 15-20 km away. In commenting upon the 700,000 age for the flanges of
tektites formed in their descent earthward, this expert concludes: "It appears that
we must reject the very recent dates for the Australian tektites: something must be wrong,
conceivably the dating of the hardpan" (12).
The Smithsonian study which was published in 1976 builds an even stronger case for the young age of australite infall, yet even it is unwilling to take that gargantuan leap and suggest that the fission-track and K-Ar ages may be in error. The report ends with these pointed observations:
No one who has seen the Port Campbell localities and examined the many perfectly preserved australites therefrom is likely to argue that these specimens are not being found essentially where they fell. The complete lack of solution etching, even on thin plates weighing as little as 0.03 gram, is a powerful argument against the australites having been subjected to terrestrial weathering, even in situ, for more than a few thousand years (6).
Evidence is against their having been transported as sediments, otherwise one would tend to find them concentrated in stream beds. They are found even on sand dunes, a fact which would rule out stream transport. They could not have been traveling through the universe over a period of 700,000 years and then come to earth 6000 years or so before the present (B.P.), otherwise the entry into the earth's atmosphere at high speed would have erased the fission tracks, which are sensitive to heat, and would have driven off the excess argon, thus re-setting the radiometric clocks. The concluding statement of the Smithsonian report aptly summarizes the dilemma:
Having reached an apparently irreconcilable impasse between the physical dating and the geographical dating of the australite fall, one can only turn to the third proposition something else is wrong. Perhaps this can better be stated as something some unsuspected factor has been overlooked (6).
To date, a proposed young age for australite infall has not been overthrown.
The last decade and a half have witnessed not only this epoch-making research come to light but also the discovery of tektites in deep-sea cores to the north, west and south of Australia. Because these marine tektites are never as large as their terrestrial counterparts, they are called microtektites, being the size of microfossils, such as foraminifera, which are less than 1 mm in diameter. Interestingly they retain the same general shapes as their larger relatives, ranging from spherical to tear dropped, disk and even dumbbell and spoon shaped (13). These microtektites spread over a vast area of the ocean bottom are now undoubtedly linked with the influx of australites upon land because of the following salient facts:
- They have identical refractive indices, which is a measure of the amount that visible light is bent passing from air into the glass, as their Australian counterparts.
- They have the same range of chemical composition as australites.
- The shapes of both are much alike.
- They are dated at identically the same age by the fission-track method 710,000 years.
- Occasionally high-magnesium microtektites are found which would correspond with the less common high-magnesium australites (13, 14, 15).
The evidence both from petrography and geochemistry strongly
indicates that Australasian microtektites belong to the infall responsible for australites
(16, 17). That being the case, a careful stratigraphic study of the deep-sea cores in
which microtektites have been located should either deny or verify an identically young
age for infall. Thus far nineteen Australasian deep-sea cores from widely scattered sites
have yielded microtektites (18, 19). For eight of these cores a detailed magnetic
stratigraphy has been determined.
Magnetic stratigraphy results from the fact that magnetic particles become oriented in the direction of earth's magnetic field as they fall out of suspension in the quiet water of ocean bottoms. Throughout geohistory the earth's magnetic field has frequently reversed so that the dominant field was not northward but southward. The boundaries between normal and reversed polarity are usually quite distinct in ocean sediments. The most critical boundary in our study is the Matuyama-Brunhes (M-B) boundary, which was first calculated by the K-Ar method to have been formed 690,000 years B.P. (20), and more recently has been dated by fission tracks in volcanic ash (21). Microtektites in large concentrations occur almost without exception in a very narrow stratigraphic range within 10 cm of the M-B boundary.
It appears to be more than a coincidence that microtektites, which have been dated at approximately 700,000 years by the fission-track and K-Ar methods, should be found in a narrow magnetic boundary zone that has been dated both on land and in the oceans at approximately 700,000 years by the same methods. It is for this reason that geologists reject the obvious terrestrial age of 5000-24,000 radiocarbon years as being embarrassingly too young.
The science of stratigraphy, which involves the correlation of cores drilled into the foraminiferal and radiolarian oozes of the ocean bottoms, has now achieved the reconstruction of climatic oscillation patterns on a worldwide basis. Such patterns can be developed irrespective of whether one accepts the validity of any of the dating systems, including C14, applied to the cores. The criteria which are commonly used to match patterns from widely separated regions are described below.
1) Oxygen isotope ratios. The ratio of the heavier O18 isotope to the lighter O16 can be determined very accurately, and it is found that during times of the dominance of polar weather the ratio is higher. The current theory is that when increased amounts of snow accumulated in the far northern and far southern latitudes, the sea levels were lower and hence there would be a relatively higher ratio of O18 to O16 (22). Conversely, the melting of the ice caps would release into the ocean the lighter O16 that had been incorporated into the snow, thus lowering the O18-O16 ratio. The oxygen isotope ratio taken from foraminifera is directly a measurement of sea levels and only indirectly a measurement of paleotemperature. While on land oxygen isotope ratios in some cases seem to be positively correlated with temperature, as, for example, those from a sequence of 87 tree rings in Alberta, Canada, which correlates nicely with weather bureau records (23). Just this year an 1800-year continuous sequence of Japanese cedar rings has been reported showing oxygen isotope patterns that match with an 800-year sequence from the Greenland ice cap (24).
2) Foraminiferal curves. Foraminifera are one-celled organisms which have a calcium carbonate shell and are a major contributor to the deep-sea sediments. The percentage of polar species to temperate or tropical species can be plotted for the length of the core and a climatic curve developed that correlates nicely with the oxygen isotope curve.
3) Coccolith curves. Coccoliths are microfauna that contribute to the oceanic sediments, and, like the foraminifera, the ratios of polar fauna to temperate or tropical fauna can be plotted using the depth of the core as the Y-axis.
4) Calcium carbonate percentages. The amount of calcium carbonate (CaCO3) in a given section of the deep-sea core can be accurately determined, and a plot of the percentages shows a good fit with the other factors related to climate. The reasoning is that during times of polar weather dominance the growth of marine organisms which are the major contributors of CaCO3 is inhibited.
5) Coarse fraction percentages. This is not the measure of the amount of CaCO3 but a determination of the average size of the calcareous clasts or fragments in the sediment. The theory is that during warm weather dominance the marine organisms grow larger and the percentage of coarse fragments would be higher.
Other methods have been developed and sometimes show a good correlation with oxygen isotope curves, such as the percentages of ice-rafted debris (25) and radiolarians (26), as well as clay/quartz ratios (27), quartz/mica ratios (28), and the coiling ratios of foraminifera (29, 30).
One of the most intensively studied cores of all the thousands of deep-sea cores retrieved to date is the Caribbean V12-122. When the top four meters of the core are evaluated on the basis of the oxygen isotope, CaCO3, coarse fraction and foraminiferal percentages, the resultant curves show fairly good parallelisms (Figure 1). Note that in this diagram as in all diagrams a fluctuation of the curve to the right denotes warm weather (W) dominance and to the left polar dominance (C).
FIGURE 1. Four independent temperature curves for the Caribbean core V12-122 show similar fluctuations (W=Warm, C=Cold). The 3-m level has been dated at 127,000 years by Th230 and Pa231 (36) and has been correlated with Barbados terrace III which is dated at 125,000 years (37). The fifth paleoclimatic curve is derived from two stalactites in New Zealand. (Re-drawn from references 45, 46, 33).
Not only can paleoclimatic curves be developed for oceanic cores but
also for terrestrial cores. One of the most problematic of all terrestrial cores has been
that of Tenaghi Philippon, Macedonia, which was drilled through 120 meters of lake bottom
and marsh sediments. Large sections are composed of peat. It would be difficult to
compress the amount of time needed for peat formation into a short chronology, unless one
were to postulate that this particular peat were the product of diluvial action; in other
words, an allochthonous peat. Also, more than a dozen radiocarbon determinations have been
made on the top few meters of the core and a reading of 47,670±2700 years has been
obtained at a depth of 16.75 m (31). Assuming a constant sedimentation rate of 25
mm/103 years computed from the upper 17 meters and extrapolating this rate to
the base of the 120 m core, one would conclude that 342,857 years of time are
represented. How can this be harmonized with a short chronology of just a few thousand
years for post-diluvial time?
Also of interest is correlating the climatic curve derived from this terrestrial core with various oceanic cores. To develop a climatic curve for land deposits one must use pollen as a temperature indicator. It has been discovered that the percentages of arboreal or tree pollen (AP) and of nonarboreal pollen (NAP), which is composed of grasses, herbs, and shrubs, are excellent climatic indices during historical times. Thus it is suggested that in pre-historic times the higher the ratio of AP to total pollen the warmer the climate would have been, and the higher the ratio of NAP to total pollen the cooler the climate. Thus a plot of AP and NAP percentages as a function of depth builds a climatic curve that can be cross-referenced with the deep-sea curves.
The question is whether it is feasible to match terrestrial curves with the deep-sea. A comparison of the two sets of curves indicates that the resultant curves have a very close fit, considering that they are constructed using different parameters. The Philippon core can be matched with the deep-sea core Al 189, which was retrieved from the central part of the Mediterranean Sea (Figure 2). Another terrestrial core that extends even longer than the Philippon core is the 190 m Sabana de Bogota core from Colombia, South America. Its climatic curve constructed out of AP/NAP ratios has a good fit with the deep-sea curve from core V19-28 which is based on oxygen isotope ratios (Figure 2). Located not far off the coast of Ecuador in the Panama basin, core V19-28 has an ash layer at 13.2 m that has been dated in the range of 225,000 to 250,000 years by four different methods, including K-Ar (32).
FIGURE 2. Correlation between two terrestrial pollen curves and two marine climatic curves from adjoining ocean basins is demonstrated. The Philippon core is dated with radiocarbon and V19-28 is dated stratigraphically by a distinct ash marker. AP=Arboreal Pollen, NAP=Nonarboreal Pollen. (Drawn from information in references 47, 32, 47, 48 respectively.)
Oxygen isotope curves can not only be derived from marine cores but
also from terrestrial speleothems. A curve based on two stalactites from Waitomo, New
Zealand, and dated by C14 dating is compared with the Caribbean V12-122 curve,
indicating that matching can be done on a worldwide basis (Figure 1) (33). Short
segments of speleothem oxygen isotope curves from North America that have been dated by Th230/U234
match nicely with cores V12-122 and V19-28 (34).
Are such synchronizations of climatic curves mere coincidences? Hardly the case. If these curves were analyzed from the standpoint of probability theory there is only a very slight possibility that even two of the cores could be matched purely on the basis of chance alone. The probability that more than two cores could be coordinated if the curves were not climate dependent would be so small that it can be safely said such curves are indeed controlled by a common variable such as climate rather than by chance processes.
Correlation between widely separated curves can be achieved by noting faunal boundaries, relationships to magnetic reversals, and the presence of volcanic ash layers. Extinctions of certain deep-sea organisms occur at the same interval in matching cores on a worldwide basis. The most convincing example of this is the global extinction of the coccolith Pseudoemiliania lacunosa which occurs at the same interval on matching oxygen isotope curves from seven cores, including V28-238 and K708-7 (see Figure 3) (44). One would not expect such precision if the deposition patterns were catastrophic and non-uniform.
FIGURE 3. The possibility of worldwide correlation is shown by comparing paleoclimatic curves from six marine and two terrestrial cores which span most of the Brunhes magnetic era during which the earth's magnetic field showed normal polarity. The M-B, or Matuyama-Brunhes boundary, marks the transition from reversed to normal polarity. The transition form glacial-type conditions to warm weather is denoted by "Terminations." The Pseudoemiliania lacunosa extinction occurs about midway in the Brunhes and serves as a worldwide stratigraphic marker. (Re-drawn from information in references 48, 50, 41, 52, 47, 47, 45, 35 respectively, left to right.)
The best way for such cores to be matched is by postulating a fairly
uniform rate of deposition. If the rate is apt to vary at certain segments of the core by
a factor of more than 2 or 3 either below or above the average rate for the whole core,
then the curves would not show a close fit. Thus it can be concluded that the
sedimentation rates have varied from each other on an average less than a factor of 2 for
any significant portion of the cores in Figure 2.
If the rates have been fairly uniform in order to produce a good fit for all these curves, then based upon the present rates of sedimentation the cores would depict a chronology many times longer than the traditional Biblically oriented chronology of 4300 to 5000 years for post-diluvial time. How does one solve this time problem if he wishes to maintain a conservative creationist approach to the subject? In probing for a solution, it is imperative that we first match these shorter core lengths with much longer sequences that extend to the M-B boundary. If that can be accomplished, we can take the tektite-determined age for the M-B boundary as a reference point for dating all deep-sea deposits that are above it.
What we have done is to select cores from widely scattered geographical areas to determine indeed if climates have fluctuated on a worldwide basis during the period of time which geologists have assigned to the Pleistocene. Of the eight cores represented in Figure 3 three extend to the M-B boundary. Of the other five, two are the longest terrestrial cores with a continuous pollen record Sabana de Bogota of northern Colombia and Tenaghi Philippon of northern Greece. There is a very good match between the Bogota core and the North Atlantic K708-7, and another fine match between the Philippon core and the West Pacific V28-238, showing that terrestrial and deep-sea cores indeed can be correlated. Again it would be most difficult to argue that such matching is purely the product of chance. The sediments of these cores most likely accumulated in situ and provide a fairly reliable picture of temperature at the moment of their deposition. Otherwise, if they were not in situ, or autochthonous, then the temperature curves would show a scrambled picture due to catastrophic activities.
The most intriguing aspect of the cores is the variety of dating methods that have been applied to them. The most commonly used method, the C14, exceeds its usual limit of 50,000 years at a depth of less than one-tenth of the way down to the M-B boundary. Core RC11-209 yields a radiocarbon date of 11,600±600 years at a depth of only 11 cm, which would give a sedimentation rate of 1 cm/103 years (35). Extrapolating this average rate to the M-B paleomagnetic boundary which occurs at 6.9 m in this particular core, the result is a figure of 690,000 years. It should be noted, however, that generally C14 extrapolated rates do not harmonize so precisely with paleomagnetic data, which are based largely on K-Ar and fission-track dating of terrestrial lavas.
Other dating methods that have been used to determine the placement of the M-B boundary either through extrapolation or interpolation are uranium disequilibrium methods, fission tracks, K-Ar, obsidian hydration, and amino acid epimerization. The first three are radiometric, and the last two involve geochemical reactions with many variables. Two of the uranium disequilibrium methods involving Th230 and Pa231 have been applied to the Caribbean core V12-122 and yield concordant sedimentation rates of 2.35 cm/103 years (36). It should be noted that uranium disequilibrium methods have not always yielded consistent results. This would date the end of the next-to-the-last polar dominance, known as Termination II, at 127,000 years (Figure 1). A recent report has correlated the high warm climatic peak that occurs immediately after Term II with a raised coral reef, which is called Barbados III and is dated at 125,000 years by Th230/U234 (37). The correlation is accomplished by an oxygen isotope analysis of mollusks from the raised coral reef and by a comparison with oxygen values from deep-sea cores, such as V28-238, which suggest a warmer climate than present and thus higher sea levels for that episode of reef growth. Actually there are three Barbados terraces, the other two being dated at 82,000 and 105,000 B.P. by the same method. These three terraces can be easily correlated with the three successive warm fluctuations just above Term II seen especially well in the Philippon and Bogota curves (Figures 2, 3).
Volcanic fragments in deep-sea cores have been dated by two methods; the fission-track method generally yields concordant results with the paleomagnetic age (38, 39), while the K-Ar results from a core that has microtektites are discordant with the paleomagnetic age (40). Two other dating methods that as yet have not achieved the stature of the radiometric methods because of non-constant rates of chemical change are obsidian hydration and amino acid epimerization (racemization), the former having been applied to several Pacific cores (41), and the latter to cores V12-122 and V28-238 which are dealt with in our study (42, 43).
If we simply take at face value the above-mentioned dating methods that have been applied to deep-sea cores, it confronts us with a strong case for the reliability of their conventional age interpretation. Thus it is important that some concrete, verifiable explanation be advanced in order to maintain a short chronology based upon Biblical data.
Since the first paleomagnetic boundary is worldwide and occurs at consistently the same location on the paleoclimatic curves, this can be utilized as a useful time marker. If the microtektites can be positively linked with the same event as australite infall and if radiocarbon dating serves to limit the age of infall to about 5000 or 6000 radiocarbon years ago, then we are forced into dating the M-B boundary at 5000 or 6000 radiocarbon years ago.
This tentative conclusion is valid only to the degree that our techniques of correlation are scientifically sound. Like a steel chain, correlation is no stronger than its weakest link. What we have done is to encircle the earth with our stratigraphic "chain" in the following way: first, link the australites on land with the deep-sea microtektites as part of the same infall of tektites; then the microtektites with the M-B boundary, which is usually placed at 690,000 years; the M-B boundary from cores in the Australasian area with the M-B boundary in cores around the world; and finally connect the deep-sea cores with the terrestrial.
If we assign an age of approximately 5000 B.P. for the M-B boundary, then the chronology for all Pleistocene paleoclimatic curves above that boundary would have to be compressed 140-fold from the conventional age of about 700,000 years. The most problematic Pleistocene core, that of Tenaghi Philippon, would likewise have to be reduced 140-fold. The C14 age of 47,670 at 16.75 m must be reduced accordingly to 340 years. Such a drastic reduction is not possible in light of the fact that C14 ages can be correlated with Egyptian chronology at least 3800 years into the past; thus at most there can be a 12-fold reduction if the figure of 3800 years is taken as the minimum time for major disagreement between C14 age and real time, as the evidence seems to indicate. This takes care of only the upper one-seventh or 17 m of the core, leaving more than 100 meters below. If we compress the C14 age at the 17 m level to the minimum allowable (3800 B.P.), then the age for the bottom of the core would be placed at approximately 26,600 B.P. (7×3800), which far exceeds the maximum age of 5000-6000 allowed by microtektite evidence. Therefore, the C14 stratigraphy at Philippon does not allow the compression of the Pleistocene time-scale to the degree demanded by C14 stratigraphy of australites found in situ in southeast Australia. It seems that we are confronted with two incontrovertible, yet incompatible, pieces of evidence.
Dilemmas such as this serve a much-needed purpose in forcing us to grapple with the problem and to begin earnest painstaking effort at working toward a solution. Further research is urgently needed to either eliminate or confirm any of the above. Let this study be a challenge to creationists to probe into the "uttermost parts of the sea" and the "recesses of the deep" (Psalm 139:9; Job 38:16) to find adequate answers. In pursuing the footsteps of the Creator even into ocean depths, who knows whether a totally new solution may be uncovered that at present is overlooked! Only time will tell.
If further research continues to validate the youthful age of australite infall, then six apparently interlocking dating methods applied to deep-sea cores must undergo complete revision, resulting in a drastic reduction of Pleistocene chronology and a greatly increased sedimentation rate for all but the uppermost deposits at least 140 times above present rates. An acceptance of the australite infall age of 5000-6000 years B.P. determined by C14 and its worldwide application through paleomagnetic and paleoclimatic correlation has implications that would challenge virtually every radiometric and non-radiometric dating method applied to cave and sedimentary deposits. Thus the present dating methods based upon fission tracks, K-Ar decay, uranium-series disequilibrium (protactinium and thorium), amino acid epimerization, obsidian hydration, and paleomagnetism may stand or fall depending upon future studies into the vast shower of tektites and microtektites in the Australasian region.
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