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Dave Matson Young Earth Specific Arguments Coral Reef

Young-earth "proof" #26: The oldest coral reef is about 4200 years old.

26. What does the age of a coral reef have to do with the age of the earth? If, in fact, the oldest coral reef is 4200 years old, so what? There is no argument here for a young earth, but such a suspicious figure (which fits so conveniently into Hovind’s flood chronology) requires investigation! During the Arkansas trial of Act 590 in 1981 the subject of coral growth came up:

Roth, [who was] not a member of the CRS [Creation Research Society], was presented as an expert on coral reefs whose thesis is that corals grow very rapidly and do not need millions of years to form massive reefs. He testified for 70 minutes, but the crossexamination was brief. Q: "What is the last sentence of your article on the growth of coral reefs?" A: "…this does not establish rapid growth of coral development." Q: "Is there any evidence that coral reefs were created in recent times?" A: "No." Q: "No further questions."


(Berra, 1990, pp.134135)

I suspect that the super-rapid growth of corals is as much a part of creationist mythology as is the super-rapid growth of humanity in ancient times or the super-rapid growth of stalagmites. You have above an admission from someone who was handpicked by creationists as an expert on super-rapid coral growth. And, what did he say? He said that his work did not establish the superrapid growth of coral. I doubt that things have changed that much since 1981. Here are a few facts on coral growth:

Under the best of circumstances … individual corals can grow no faster than 0.5 – 1.0 inch per year. The coral reefs, formed from the breaking up and cementation of coral sand, grow much more slowlyperhaps less than a tenth as fast.

Weber reports [op. cit., pp. 29-31] that H.S. Ladd has drilled bore holes through the coral cap that crowns the volcano underlying Eniwetok atoll, in order to measure the thickness of coral that has grown there since the lava cone began to sink beneath the sea. At one point, Ladd had to drill 1380 meters (almost ninetenths of a mile!) before reaching the lava lip of the volcano. It is inconceivable that that much reef could have formed in less than 130,000 years, let alone during the few dozen centuries since Noah’s flood (2348 B.C.).


(Zindler, 1989, pp.20-21)

We’re talking about a coral reef 54,330 inches thick! By popular creationist reckoning, that reef had to have formed after the flood. A flood that has reworked the surface of the earth, literally digging up miles of sediment, would certainly have destroyed any antediluvian reefs. Indeed, one wonders how the coral organisms even survived! Since the Eniwetok coral reef was neither destroyed by Noah’s flood nor covered with a thick layer of sedimentary rock, we may safely assume that, according to the creationist scenario, it grew after the flood. (If we use Dr. Hovind’s figure of 4200 years for the age of that coral, then that reef had to grow 12.9 inches per year! )

Even if we ignore the time it took for the volcano beneath Eniwetok to form and generously use the higher rate of individual coral growth under optimum conditions, we wind up with 54,000 years for that reef to form! Thus, we have plain evidence that at least one reef was much, much older than 4200 years or so.

Here are some more facts on coral growth:

Hoffmeister made careful observations on the growth rate of the most dominant reefbuilding coral in the Florida-Bahama area, Montastrea annularis, by marking many specimens in their underwater habitats, and then observing and measuring them over a period of years. … The fastest growth rate of these corals which Hoffmeister and his associates found was 10.7 millimeters (about two-fifths of an inch) per year in height. This would produce one foot of coral rock in 28.5 years if its growth were not interrupted or slowed down. However, there are numerous influences which directly interfere with the growth processes of the coral animals. Some of these factors as observed by A. G. Mayor during a four-year Carnegie expedition to the Samoan Islands were: (a) silt and mud washing over and smothering coral colonies, (b) high temperatures due to hot sun during low tides, (c) drenching tropical rains which not only smothered and killed many coral colonies by the resulting mud, but diluted the sea water to such a low salt content that the coral polyps could no longer live in it.


(Wonderly, 1977, p.28)

In Samoa, where we find the fastest coral grow rates known anywhere, some thin, branchy types of coral may actually grow 5 inches in a year. Obviously, the thin, branchy types of coral will have the faster growth rates by far in that their energy is not dissipated in bulk.

If one measures the rate of growth of the tips of these branches he will find it to be up to about 100 mm. (about 4 inches) per year in the Florida-Bahama region [Shinn, 1966], and up to 125 mm. per year in Samoa [Mayor, 1924]. This is the fastest growing genus of the reef-forming corals; however, it must be remembered that the open nature of the colony (somewhat like the branches of a tree) prevents this coral from making anything like 100 mm. of solid buildup of reef per year. Wave action and other forces wear and break the branches, whereupon they fall to the base to add their volume to the reef mass.


(Wonderly, 1977, p.31)

Thus, we see that the growth of a coral is often interrupted. Therefore, just as it is true for stalactites (see #22), the maximum rate of coral growth over short intervals of time will greatly exceed the average rate. The average rate, itself, will be much greater than the reef-building rate which involves the breaking up and consolidation of the more delicate and faster growing corals in addition to erosion and other factors.

Consequently, creationists who quote individual rates for fast-growing corals as an estimate for reef-building times are being less than honest.

Mayor found the average growth in height of healthy colonies of corals of the massive type, belonging to Genus Porites, to be 17 mm. [2/3 inch] per year. He also found this kind of coral to be one of the most effective reef-building types in Samoa. Since coral skeletons of this massive type are not readily broken up by wave action, Mayor estimates that "a reef-wall composed of massive Porites might attain a thickness of 55 feet in 1000 years, while a reef composed of branching Porites might grow upward at least 25 feet in the same period of time." [Mayor, 1924, pp.6061] (This is of course assuming that the ocean level and other environmental conditions would remain favorable for the entire period.)


(Wonderly, 1977, p.31)

Since a reef could scarcely grow much faster than its main coral component, you can see that the rate of 1 inch per year (which I used above to get 54,000 years) is quite generous. Just how generous it is remains yet to be seen.

As a swimmer passes over a submerged reef, he sees numerous clumps (colonies) of coral growing on the surface of the reef. These colonies have their own growth rates, as explained in the previous section, but most of them are destined to be drastically changed before they make their final contribution to the reef height. Boring and encrusting organisms frequently stop the growth of the colony or of a part of it. Eventually the entire colony may be broken loose by wave action and rolled down the side of the reef to a lower level.

In addition to this sort of delay in reef growth, complete stoppages occur. Each stoppage of the reef’s growth leaves its mark in what is called an "unconformity" in the substance of the reef mass. Unconformities are thus caused by major disturbing factors such as a drastic change in sea level (13), the development of muddy or other unfavorable environmental conditions in the water of the area, and volcanic eruption. In many such cases, the fossil remains which are found on the unconforming surface in the reef mass are abruptly different from those above. At least one such unconformity was observed by Hoffmeister and his associates when they made core drillings into the reefs in the Florida Keys [Hoffmeister, 1964, p.356]; and many such unconformities were observed in the (far deeper) drillings made in the Marshall Islands by the U. S. Geological Survey.

Thus it is seen that it would be absurd to think that the length of time which was required for the formation of a large reef could be calculated by merely dividing the depth of the reef by the average growth rate of healthy coral colonies. The upward growth of the reef is always much slower than the growth of the colonies. In fact, this phenomenon is selfevident in the observation that most of the numerous coral reefflats in the Pacific which have been studied during the past 75 or more years are wearing down at about the same rate that they are being built up [Mayor, 1924, p.65]. Of course we are not saying that no material is permanently added to the entire reefflat each year, but rather, that the leveling forces spread the deposited skeletal matter out over a wider area, broadening the entire reef as time progresses.


(Wonderly, 1977, pp.31-32)

Eniwetok is one of those deeply drilled sites in the Marshall Islands. Thus, our estimate of its age is much too small because we have not allotted time for even the identified instances of total interruption and stoppage of its coral growth.

Let me remind you of just one scenario that must have played itself out over and over again. Coral can’t grow above low tide as it would dry out and overheat in the tropical sun. Consequently, once a reef has reached that height it cannot go any further unless the ocean level rises or the sea floor sinks. How long a reef, already at the low tide level, might have to wait for such a "green light" is anybody’s guess. Ten thousand years might pass before a reef added another foot to its height!

Scientific study has given us reasonable estimates of short term reef growth. Long term reef growth, of course, would have a much smaller rate. The longer the time period involved, the less likely that ideal conditions will prevail. It’s like gambling in Las Vegas. It’s easy enough to win a couple of hands back to back in a card game, but you can be sure that such a favorable streak won’t hold up for long. The law of averages will take its toll.

There have been at least two very careful calculations made, of the total amount of coral skeletal material added per year to a given surface of reef, in areas where normal growth is going on. It is significant that none of the research on growth of corals which we are citing was carried out for the purpose of demonstrating that the reefs are of great age. These research projects were done with a view to showing the rate at which corals can be expected to build up barrier reefs which are of value in protecting harbors.

Mayor made a very careful series of observations to determine the amount of actual mineral (skeletal matter) which was being secreted and deposited per square yard on one of the typical, normally growing reefflats. An extended period of observation and measurements made during the Carnegie expeditions of 1917 to 1920, to the Samoan Islands, under Mayor’s supervision, revealed that the total thickness added to the reef flat per year was approximately 8 millimeters [less than 1/3 inch].

At this point let us compare the upward growth we have cited, with the total depth of the thickest known coral reefs–the atolls in the Marshall Islands. During the drillings which were made into these islands, the thickest coral reef deposit found was that of Eniwetok atoll, where one drilling, as stated above, had to go through 4,610 feet of reef deposit before striking the volcanic rock (basalt) base. Another drilling nearby extended through reef deposit for 4,158 feet before reaching the volcanic base [Ladd, 1960, p.863ff]. It is of course true that no one is able to determine the exact length of time which was required for growing such an extensive reef, but it is obvious that it was a very long process. If we divide the thickness of the Eniwetok reef by Mayor’s 8 mm. of deposit per year, we arrive at 176,000 years of continuous growth required for the laying down of this much thickness. However, this would be a false picture, because of the many factors which retard the build-up of the reef, as discussed above. Thus the total length of time required for forming the 4,610 foot reef deposit of Eniwetok was undoubtedly many times the 176,000 years (18).


(Wonderly, 1977, pp.32-33)

In his last footnote, Wonderly informs us that geologists have placed the earliest deposits at Eniwetok within the Eocene Epoch. That means that the true age of the reef is somewhere around 40 million years, roughly speaking!

Wonderly goes on to explain in detail (1977, pp.33-34) why it is naive to imagine that corals grew at tremendously faster rates in ancient times. I’ll leave it to the reader to investigate that point should it be of interest to him or her.

For the stubborn mind, which refuses to grasp the great age of the Eniwetok atoll, we could present even more facts. Wonderly devotes four lovely pages to describing the details of the cores taken from Eniwetok Atoll, and even that can’t do justice to the whole story. The details are fascinating and reek of old age. For example, at one time the coral reef was above water for such a long time that trees grew on it! How long that went on is anybody’s guess. Unfortunately, we have to move on. I’ll leave you with a final quote from Wonderly who, by the way, is a devout Christian as well as a competent geologist. He undertook this work because he felt that "scientific" creationism, by associating the Bible with their ridiculous arguments for a young earth, were making the Bible a target for ridicule.

Thus a reasonably good reconstruction of the history of the Eniwetok atoll has been made, by taking note of the rock and sediment types, the many kinds of marine fossils, the distinct unconformities, and the kinds of pollen and other remains of terrestrial life. All of these tell us that the reef has had a long and varied history, with numerous major interruptions in its development.


(Wonderly, 1977, p.36)

So much for Dr. Hovind’s 4200-year limit on the oldest reefs!

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