How Good Are Those Young-Earth Arguments?
Given enough time, erosion will strip away exposed strata. The fact that these sediments are in perfect textbook order is hardly surprising since the Atlantic sea floor has been continually spreading apart since the late Jurassic. Yet another mechanism that can lead to decreasing K-Ar ages with time is the following, in a flood model:
1. An abstract of the presentations to follow
Carbon is said to be cosmogenic because it is produced by cosmic rays hitting the Earth's atmosphere. The equation for the radioactive decay of 14 C is: Photosynthesis is the primary process by which carbon moves from the atmosphere into living things. Radioactive Subject to change from one element to another. Frog Salamander Toad Toadstone.
Is it possible that Dr. Hovind, who taught earth science for 13 out of his 15 years as a high school science teacher, doesn't understand the concept behind the geologic column?
The thought boggles the mind! On top of that, Dr. Hovind is simply wrong in his claim that no place on Earth has a full set of representative strata. John Woodmorappe, a young-earth creationist, has admitted that representative strata from the Cambrian to the Tertiary have been discovered lying in their proper order in Iran, by the Caspian, the Himalayas, Indonesia, Australia, North Africa, Canada, South America, Japan, Mexico, and the Philippines!
Woodmorappe, , p. Morton, a professional geophysicist, has reported that portions of Alaska also contain strata representing all these geologic periods lying in their exact textbook order. Phone conversation between Edward Babinski and Glenn Morton, as relayed to me. Sometime later he identified three wells for me in McKenzie County, North Dakota, which had penetrated all the geologic periods in their correct order.
Morton also indicated that the East China Sea, the Juixi pronounced jewshi basin in China and many more areas could be added to the list. So, the geologic column definitely does exist! That is to say, there are a number of locations where every period of the geologic column from the Cambrian on up is present and in proper order.
Wherever we find relatively undisturbed areas without any of the obvious signs of mountain building, that strata is always in the textbook order. Some of the geologic periods may be missing, either because they were never laid down at that location or because they have since eroded away.
However, the relative order of those present is preserved. See Topics G4b and G4c for a discussion of missing and out-of-order strata. Showing that the geologic column is fully represented in various places is not my main concern here. Far more important is Dr. Hovind's fundamental misunderstanding of the geologic column, which seems to be shared by many creationists.
The geologic column is an ideal, complete, chronological reference frame that defines the status of those strata having more or less a worldwide distribution or correlation in time. For example, local strata that can be traced to places where it lies above strata of the Mississippian Period, and to other places where it lies below strata of the Permian, or which can be dated or identified as belonging to that interval, is defined as belonging to the Pennsylvanian American or Upper Carboniferous European Period.
Of course, we are assuming the usual order here. Allowances must be made for overturned strata, etc. In the geologic column American version , the Pennsylvanian Period is the sixth period in the Paleozoic era and is characterized in many places by great coal-, oil-, and gas-bearing deposits. It contains the record of the first reptiles, etc. The geologic column is like a yearbook with the pictures of all the graduating students in it.
No one expects that every one of those students will show up for a particular dance! Neither does the geologist expect that some locality must exhibit all the known strata. The point is that the earth's strata has a very definite chronological order to it, and that order, taken at its most complete, ideal form, serves as an abstract reference frame for defining the actual strata of each locality. The question as to whether some locality has all the periods in the geologic column is only of academic interest; it has no bearing on the fitness of the concept.
That is usually what is meant when one refers to the geologic column. If not that, then the phrase is simply being pressed, rather loosely, as another name for the strata of some locality or localities. None of these charges amount to a hill of discarded beans. We can't examine every such claim, but we can look at a few examples. Hovind means fossils which cross several strata.
Usually that means fossilized, vertical tree trunks. Creationists are attacking a straw man. No geologist claims that every little stratum requires thousands of years to be laid down! The strata associated with polystrate fossils invariably show evidence of relatively rapid deposition. They show a photo of the Yahtse River area in Alaska, which depicts a number of upright, broken-off stumps stripped of most of their branches.
The taller stumps poke out above the alluvial mud. This is the result of natural processes accompanying river course change. A couple of pages later we find a photograph showing how trees can be buried fairly quickly in another way. In this case, volcanic ash has partially buried a forest whose trees are mostly reduced to broken-off stumps stripped of their branches. Continuing volcanic eruptions over a period of years dead trees last a long time!
In some cases, burial might well be less than instantaneous. In the San Francisco area fossils of cedar and redwood dated at 23, years are found in place 20 feet below present sea level. This may be due to a rising sea level from melting ice-caps. Encyclopedia Americana , Annual [Geology]. A similar find exists off the coast of Japan where remnants of a forest of willows and alders are found in 70 feet of water.
They are some 10, years old Chorlton, , p. As to the foot whale, standing on its tail, which was found by the GREFCO Corporation near Lompoc, that being an outstanding example of a polystrate fossil, you may rest assured that geologists do not assume that it remained on its tail until slowly buried by diatoms!
More likely it died a natural death, sank to the bottom for a time, and was buried in some kind of underwater avalanche which left it in its vertical position. Here's what a Christian geologist had to say:. Before the discovery of rapid, submarine sediment flows the circumstances under which these animals were buried was very much a mystery 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.
Thus, the mystery of Lompoc poses no problems for standard-brand geology. However, we can do even better. Thanks to that modern wonder of wonders, the Internet, a complete accounting of the Lompoc whale mystery is only keystrokes away! His material comes directly from those folks at the Los Angeles Museum of Natural History who were involved in the excavation. The original source of our story appears to be K.
Russel, who wrote an article in Chemical and Engineering News Oct. Some "facts" were wrong from the start. To begin with, the whale fossil was not buried vertically.
The angle was more like degrees from the horizonal. Most importantly, the skeleton lay parallel to the bedding plane, meaning that the site was, more or less, once a level sea floor. The fossil was buried by the same kind of diatomites that accumulated in deep bays and basins along the Pacific Coast during Miocene times. These sediments lack any sedimentary structures that would indicate catastrophic deposition. Rather, the strata exhibit laminations indicative of slow accumulation on an anoxic bay bottom.
Indeed, a partially buried, fully connected articulated whale skeleton is slowly being buried even now off the California coast! It was discovered about 10 years ago by a deep-sea submersible. Plate tectonics wrote the final chapter. As the Transverse Ranges were being folded and pushed up, the sea floor on which our whale had settled and, in time, had been buried, was now subject to folding. As a result, that whale skeleton became tilted along with the strata on which it lay.
Now that we have the real facts, we can see that this whale fossil is actually a good reason for rejecting Noah's flood as the source of the geologic column! Funny, how creationists often shoot themselves in the foot while trying to attack conventional geology! In order to collect the point, creationists must show that polystrate fossils exist where they shouldn't be.
That involves a lot more work than conjuring up interesting pictures and local stories accompanied by much speculation.
Missing layers are no problem at all once one understands that the geologic column is an abstract conceptual tool, an ideal reference frame, which gives order to the overall geologic record. It's like a dictionary listing the more important English words. No one expects that every one of those words will be present in some history book!
Neither does the geologist expect any particular locality to exhibit all the known strata. Has it occurred to you that the thick strata now being formed in the oceans off our coasts are not forming on the mainland? Thus, we have one cause of our missing strata, namely that it might not have been laid down in the first place!
The late Jurassic, for instance, was not laid down everywhere; where land existed no sediment was being added, except in lakes, dune accumulations, and in certain other situations. Another possibility is erosion. Given enough time, erosion will strip away exposed strata. Large parts of Canada have been, with the help of glaciers, stripped all the way down to the Precambrian rock! Talk about missing layers! Again, missing strata present no problem for geologists. The geologic column has no missing strata because it is a catalog of all known strata; it is not a physical locality but a chronological compilation of all localities, an ideal reference frame.
Anyone who has studied a decent geology text, a result of numerous years of careful work by thousands of trained geologists who made numerous field trips to assorted mountains and valleys in order to chip away at the earth's old rind, will appreciate just how messy things can get. Nevertheless, except in the very worst cases of mangled rock, there is almost always a pattern to it which holds the key to its history.
Common sense suggests that the strata have been folded, and careful mapping bears that out. Footprints, mudcracks, ripple marks, cross laminations, and various other clues found on the surfaces of bedding planes often confirm beyond any shadow of a doubt that a given sequence of strata have been overturned.
A strata sequence of B-C-A-B-C, to give another example, suggests that the strata A-B-C had been shoved upon itself after breaking along a front, and that stratum A- had eroded away. A geologist studying the site would look for evidence of an overthrust at the boundary of C-A. To hear creationists complain, you'd think the strata were shuffled like a deck of cards without a clue as to which way is up!
A careful mapping of an area is usually enough to unravel the mystery or at least point to a likely solution. Strahler , Chapter 40 provides an excellent discussion on the nature of overturned strata, including a thorough discussion of the Lewis Overthrust.
When geologists look at areas which haven't been seriously disturbed for great ages, such as the Grand Canyon, they always find the strata in the right order.
Some strata may be missing, but the order will be correct. Such studies soon made it abundantly clear to the early geologists that the earth's strata has a very specific order.
Thus arose the concept of the geologic column. Let me also add that radiometric dating supports only one order for the geologic column, the same order found in undisturbed areas. Radiometric dating, where applicable, also clearly identifies reversed strata and other anomalies.
Such anomalies, as already noted, can often be identified by extended mapping of an area. More evidence illustrating the correct order of the geologic column may be had by mapping the bottom sediments of the Atlantic Ocean according to their geologic ages.
If we move away from the Mid-Atlantic Ridge, either towards the United States or North Africa, we move successively from the recent sediments of the Quaternary period to the Pliocene, Miocene, Oligocene, Eocene, and Paleocene epochs, which make up the Tertiary period, to the late, middle, and early Cretaceous periods, and finally into the late Jurassic period just beyond the continental shelves of either coast McGeary and Plummer, , p.
The fact that these sediments are in perfect textbook order is hardly surprising since the Atlantic sea floor has been continually spreading apart since the late Jurassic. As new sea floor emerges and spreads outward it picks up the most recent sediment, which means that the farther away we look from the Mid-Atlantic Ridge the older the sediment is in the bottom layer.
We should, therefore, find the whole textbook sequence as far as it goes in its proper order as the sea floor is a perfect place for the continuous deposition of sediment, and that is exactly what we do find! A similar story holds for the East Pacific Ridge, which runs roughly south of central Mexico.
If we move northwest towards the Marianas Islands south of Japan we cross the same order of geologic epochs and periods as we did in the Atlantic! Again, this is not surprising since the Pacific sea floor is spreading out from that ridge, meaning that it would also record the true order of sediment deposition. Naturally, it will agree with the order found in the Atlantic. There is really no question whatsoever as to the proper order of the world's major strata.
It is a sign of sheer desperation that today's creationists would even try to challenge such a solidly established fact as the geologic column. The creationist claim of misplaced fossils, i. The one, shining exception, the supposed man-tracks along the Paluxy River in Texas, which had enough "substance" to be the subject of a creationist movie, has proved to be an embarrassing bust.
It is an embarrassment to all but the most die-hard, head-in-the-sand creationists. A thorough discussion of all the claims for "misplaced" fossils and manufactured items would fill an entire book. We can only scratch the surface.
This hammer was supposedly dug out of Ordovician strata. In fact, it is a 19th century miner's hammer of recent American historical style. Carl Baugh is something of an embarrassment even to creationists in that he is continually finding things in the Paluxy River area which just ain't so!
Perhaps you've heard of "Glen Rose Man" which was created from a fish's tooth! That was one of Baugh's productions.
As for the hammer, which was actually found by others near London, Texas in the s, supposedly in an Ordovician stone concretion, it merely came into Baugh's possession. The stone concretion is real, and it looks impressive to someone unfamiliar with geological processes. How could a modern artifact be stuck in Ordovician rock? The answer is that the concretion itself is not Ordovician.
Minerals in solution can harden around an intrusive object dropped in a crack or simply left on the ground if the source rock in this case, reportedly Ordovician is chemically soluble. This is analogous to stalactites incorporating recent objects in their paths as they grow. The rapidity with which concretions and similar types of stone can form is evident in soil caliche development. For years creationists claimed that human footprints could be found side by side with dinosaur prints at this site near Glen Rose, Texas.
The complete story of creationist doings in and around the Paluxy River is, with one or two notable exceptions, a classic study of wishful thinking gone awry. Few studies shed more light on the creationist mentality than does the history of the Paluxy River "mantracks. There was even a seductive creationist movie, Footprints in Stone , which "documented" the "mantracks" found along the Paluxy River.
Laurie Godfrey showed that the film was pseudoscientific. The "man prints" in the film had been darkened, with either shellac or oil, making them look far more human than they would have otherwise Godfrey, , p. In some cases the "man print" was a portion of a larger footprint which was probably made by a dinosaur. One of Godfrey's students wrote to Eden Films to ask whether or not duplicates of their casts could be purchased for firsthand examination. Their answer was "no, not yet," leaving Laurie Godfrey wondering " Why not yet?
Coombs, a vertebrate paleontologist who has studied dinosaur tracks, and Dr. Gomberg, an expert on the anatomy of the primate foot, both watched the film and concluded that they saw no genuine human tracks except those made during a modern demonstration. They concluded that some of the prints shown were genuine in the sense that some kind of animal made them, but the details from the film were too poor to draw any conclusions.
It is fortunate that some Texas paleontologists have examined firsthand the Glen Rose tracks. Langston also noted that one of the most widely reproduced footprint photos of Paluxy man shows a portion of a poor print of a tridactyl dinosaur; this may be clear, however, only to someone who, having studied the anatomy of the dinosaur foot, knows what to look for.
Milne [ ] makes the same point using photographs of in situ "man prints" taken directly from creationist literature. These "man prints" are nothing more than dinosaur toe impressions, selectively highlighted, with sand obscuring places where the rest of the dinosaur's foot might show. The existence of claw marks on some of the best series of "giant man prints" is now acknowledged by creationist John D.
This includes the McFall track, which is shown in Footprints in Stone. After commenting on the film's unbalanced testimonials from supposed "experts," a group of commentators that did not include a single vertebrate paleontologist or paleoichnologist an expert on the tracks of extinct critters , Laurie Godfrey concluded: Before long others had visited the site.
A study of stride length added additional support to the obvious. Nor has previous paleontological studies of the area offered any hope for creationists. Fossils typical of the Cretaceous were found in the Cretaceous strata. Mammoth remains were found above that strata in recent deposits, but never embedded in the Cretaceous.
The Ryals Trail, the McFall site, Taylor's Trail, and other items were examined and discounted as human trackways or footprints. The details of these studies are too numerous to repeat here. In September of Glen Kuban and Ronnie Hastings noticed that coloration patterns, due to secondary infilling of the original depressions, patterns previously noticed on only some of the Taylor site tracks, now appeared on tracks of all four alleged human trails.
The coloration clearly brought out the dinosaurian nature of the "human" footprints! A few creationists became so hysterical that they actually hinted that evolutionists might have painted in these markings! Taylor was so impressed with Kuban's guided tour of these problems that he withdrew the film Footprints in Stone from public circulation! Schadewald, , p. In the March Acts and Facts , an anonymous author presumably Henry Morris defends John Morris' half-hearted retraction in an unapologetic apologetic.
Regarding John Morris' hints about fraudulent colorations, the anonymous author of "Following Up on the Paluxy Mystery" notes that "no evidence of fraud has been found, and some hints of these dinosaur toe stains have now possibly been discerned on photos taken when the prints in question were originally discovered.
Indeed, the original creationist interpretation of the trackways is characterized as "not only a valid interpretation but arguably the best interpretation of the data available at that time. Another creationist organization with a heavy stake in the Paluxy River footprints is the Bible-Science Association.
About a month later, the BSA finally broke its silence. The statement made no mention of Kuban's work or of the contribution that the "Raiders of the Lost Tracks" had made. Schadewald referred to it as "whitewash as usual from the Bible-Science Association," but he held out hope that they would yet come clean. Meanwhile, as if nature intended to add insult to injury, the colorations were becoming more and more distinct as the years rolled by!
The "human" footprints were turning into dinosaur footprints! Glen Kuban , pp. The colorations provide strong confirmation that all the trackways on the Taylor site are dinosaurian.
Even before these colorations became more prominent, the tracks did not merit a human interpretation. The upshot of all this is that many creationists, at least the more sophisticated ones, have had the good sense to abandon this argument. Hopefully that includes Dr. The die-hards, of course, continue to dream of finding their Holy Grail along the Paluxy River, a find which will magically banish evolution along with years of scientific study.
I wouldn't be a bit surprised if a few of them are still poking around the Paluxy River even today. Thus, from time to time, we may expect pathetic attempts to rejuvenate the Paluxy River juggernaut which had sunk of late.
Hovind has a slide of a trilobite which was "stepped on" by a human! This looks suspiciously like one of the bogus Meister tracks Conrad, , pp. Meister's specimen, found in near Antelope Springs, Utah, was offered as evidence that a trilobite was stepped on by a human wearing a boot with a heel. In a debate Reverend Boswell claimed that it had been tested by three laboratories around the world! Sounds pretty impressive, huh?
In fact, it is nothing more than a slab of Wheeler shale that has a fragment spalled off in the form of a footprint, which reveals a trilobite, Erathia kingi. To fully appreciate that fact, which has been established beyond any reasonable doubt, you should read Conrad's account. The Olmo, Castenedolo, and Calaveras Skulls: Creationists have made some interesting claims about these fossils. In his book, the Handy Dandy Evolution Refuter , Robert Kofahl stated that the above fossils were essentially modern and yet were found buried in very old strata.
Creationist Explanation, Kofahl and Kelly Segraves suggest that the above fossils were relegated to dusty museum closets and forgotten because they didn't fit the evolutionary scheme. Scientific Creationism , one of Henry Morris' classic works, states that the Castenedolo and Olmo skulls were found in undisturbed Pliocene strata in Italy. The Bible Science Newsletter had this to say from: Conrad, , p. Another example of how people react when the evidence does not agree with their philosophical position is the treatment which the Castenedolo skull received.
This totally modern type skull was found in Pliocene strata, dated at one-half million years. Because this discovery did not agree with preconceived ideas, it is rarely mentioned in textbooks or other literature. As the professional creationist watcher might suspect, there was more to the story. Conrad , p. The bones from Castenedolo, near Brescia in Italy, belong to several skeletons of men, women, and children and were found on various occasions in a shelly bed of sand and clay, of marine origin and of Pliocene age.
It seems to me to be a certainty that water and gas will enter rocks through tiny cracks and invalidate almost all radiometric ages. Let me illustrate the circulation patterns of argon in the earth's crust. So argon is being produced throughout the earth's crust, and in the magma, all the time. In fact, it probably rises to the top of the magma, artificially increasing its concentration there.
Now, some rocks in the crust are believed not to hold their argon, so this argon will enter the spaces between the rocks. Leaching also occurs, releasing argon from rocks. Heating of rocks can also release argon. Argon is released from lava as it cools, and probably filters up into the crust from the magma below, along with helium and other radioactive decay products.
All of this argon is being produced and entering the air and water in between the rocks, and gradually filtering up to the atmosphere. But we know that rocks absorb argon, because correction factors are applied for this when using K-Ar dating. So this argon that is being produced will leave some rocks and enter others. The partial pressure of argon should be largest deepest in the earth, and decrease towards the surface.
This would result in larger K-Ar ages lower down, but lower ages nearer the surface. So this confirms that argon can travel from rock to rock when one rock is heated. Now, argon is very soluble in magma, which can hold a lot of it:.
After the material was quenched, the researchers measured up to 0. They noted, 'The solubility of Ar in the minerals is surprisingly high'. I note that this concentration of argon, if it were retained in the rock, would suffice to give it a geological age well over nillion years, assuming an average concentration of potassium. This is from a paper by Austin available at ICR.
This paper also discusses Mount St. Helens K-Ar dating, and historic lava flows and their excess argon. So magma holds tremendous amounts of argon. Now, consider an intrusive flow, which cools within the earth.
All its argon will either remain inside and give an old age to the flow, or will travel through surrounding rock, where it can be absorbed by other rocks. So magma should have at least 20 times as much argon as a rock million years old by K-Ar dating. In fact, the argon in the magma may well be even higher, as it may concentrate near the top.
This amount of argon is enough to raise 20 times the volume of magma to a K-Ar age of million years, and probably times the volume of the magam to an age of 57 million years.
So one sees that there is a tremendous potential for age increases in this way. It is not necessary for this increase in age to happen all at once; many events of this nature can gradually increase the K-Ar ages of rocks.
In general, older rocks should have more argon because they have been subject to more exposure to such argon, but their true age is not necessarily related to their K-Ar radiometric age. We can also consider that most volcanoes and earthquakes occur at boundaries between plates, so if the lava has flowed before, it is likely to flow again nearby, gradually increasing the age.
I suppose earthquakes could also allow the release of argon from the magma. Other mechanisms include dissolving of rock, releasing its argon, fracturing of rock, with release of argon, argon from cooling lava under water entering the water and entering other rocks, and argon from cooling lave entering subterranean water and being transported to other rock. There are so many mechanisms that it is hard to know what pattern to expect, and one does not need to rely on any one of them such as more argon in the magma in the past to account for problems in K-Ar dating.
Since even rocks with old K-Ar dates still absorb more argon from the atmosphere in short time periods, it follows that rocks should absorb quite a bit of argon over long time periods, especially at higher pressures. In fact, if a rock can absorb only a ten millionth part of argon, that should be enough to raise its K-Ar age to over million years, assuming an average amounts of potassium. It wouldn't require many internal cracks to allow a ten millionth part of argon to enter.
Also, as the rock deforms under pressure, more cracks are likely to form and old ones are likely to close up, providing more opportunity for argon and other gases to enter. I mentioned a number of possibilities that could cause K-Ar dates to be much older than the true ages of the rocks. Here is another way that K-Ar dates can be too old: If we assume the earth went through a catastrophe recently, then the crustal plates might have been agitated, permitting lava and argon to escape from the magma.
Thus a lot of argon would be filtering up through the crust. As intrusive flows of lava cooled inside the crust, they would have been in an environment highly enriched in argon, and thus would not have gotten rid of much of their argon. Thus they would have hardened with a lot of argon inside. This would make them appear old. The same goes for extrusive flows on the surface, since argon would be filtering up through the earth and through the lava as it cooled.
In areas where tremendous tectonic activity has taken place, highly discordant values for the ages are obtained. The difficulties associated are numerous and listed as follows:. There seems to be a great deal of question regarding the branching ratio for K40 into Ar40 and Ca But the value is not really known.
The observed value is between 0. However, this doesn't remedy the situation and the ages are still too high [low? The geochronologists credit this to "argon leakage". There is far too much Ar40 in the earth for more than a small fraction of it to have been formed by radioactive decay of K This is true even if the earth really is 4. In the atmosphere of the earth, Ar40 constitutes This is around times the amount that would be generated by radioactive decay over the age of 4.
Certainly this is not produced by an influx from outer space. Thus, a large amount of Ar40 was present in the beginning. Since geochronologists assume that errors due to presence of initial Ar40 are small, their results are highly questionable. Argon diffuses from mineral to mineral with great ease. It leaks out of rocks very readily and can move from down deep in the earth, where the pressure is large, and accumulate in an abnormally large amount in the surface where rock samples for dating are found.
They would all have excess argon due to this movement. This makes them appear older. Rocks from deeper in the crust would show this to a lesser degree. Also, since some rocks hold the Ar40 stronger than others, some rocks will have a large apparent age, others smaller ages, though they may actually be the same age.
If you were to measure Ar40 concentration as function of depth, you would no doubt find more of it near the surface than at deeper points because it migrates more easily from deep in the earth than it does from the earth into the atmosphere.
It is easy to see how the huge ages are being obtained by the KAr40 radiometric clock, since surface and near-surface samples will contain argon due to this diffusion effect. Some geochronologists believe that a possible cause of excess argon is that argon diffuses into mineral progressively with time. Significant quantities of argon may be introduced into a mineral even at pressures as low as one bar.
If such [excessive] ages as mentioned above are obtained for pillow lavas, how are those from deep-sea drilling out in the Atlantic where sea-floor spreading is supposed to be occurring? Potassium is found to be very mobile under leaching conditions. This could move the "ages" to tremendously high values. Ground-water and erosional water movements could produce this effect naturally.
Rocks in areas having a complex geological history have many large discordances. In a single rock there may be mutually contaminating, potassium- bearing minerals. There is some difficulty in determining the decay constants for the KAr40 system. Geochronologists use the branching ratio as a semi-emperical, adjustable constant which they manipulate instead of using an accurate half-life for K A number of recent lava flows within the past few hundred years yield potassium-argon ages in the hundreds of thousands of years range.
This indicates that some excess argon is present. Where is it coming from? And how do we know that it could not be a much larger quantity in other cases? If more excess argon were present, then we could get much older ages. It is true that an age difference in the hundreds of thousands of years is much too small to account for the observed K-Ar ages. But excess argon is commonly invoked by geologists to explain dates that are too old, so I'm not inventing anything new.
Second, there may have been a lot more more argon in the magma in the past, and with each eruption, the amount decreased. So there would have been a lot more excess argon in the past, leading to older ages. For rocks that are being dated, contamination with atmospheric argon is a persistent problem that is mentioned a number of times.
Thus it is clear that argon enters rock easily. It is claimed that we can know if a rock has added argon by its spectrum when heated; different temperatures yield different fractions of argon. It is claimed that the argon that enters from the atmosphere or other rocks, is less tightly bound to the crystal lattice, and will leave the rock at a lower temperature.
But how do we know what happens over thousands of years? It could be that this argon which is initially loosely bound if it is so initially gradually becomes more tightly bound by random thermal vibrations, until it becomes undetectable by the spectrum technique. The fact that rock is often under high pressure might influence this process, as well. The branching ratio problem We now consider in more detail one of the problems with potassium-argon dating, namely, the branching ratio problem.
Here is some relevant information that was e-mailed to me. There are some very serious objections to using the potassium-argon decay family as a radiometric clock. The geochronologist considers the Ca40 of little practical use in radiometric dating since common calcium is such an abundant element and the radiogenic Ca40 has the same atomic mass as common calcium.
Here the actual observed branching ratio is not used, but rather a small ratio is arbitrarily chosen in an effort to match dates obtained method with U-Th-Pb dates. The branching ratio that is often used is 0.
Thus we have another source of error for K-Ar dating. Henke criticized some statements in my article taken from Slusher about the branching ratio for potassium. Slusher asserted that the best known value of the branching ratio was not always used in computing K-Ar radiometric ages. Unfortunately, Dalrymple says nothing about the calculation of the branching ratio. He simply gives the correct value for the K-Ar system.
The issue is not just how well this was known in the past, but which value was actually used, and whether dates published in the past have been computed with the most recent value. Often values for constants are standardized, so that the values actually used may not be the most accurate known. All that Dalrymple says is that his ages were all recomputed using the most accurate values of the constants.
This implies that some of them were originally computed using less accurate values, which is similar to Slusher's point. He admits that Slusher's statements about it would have been true in the 's and early 's, but are no longer true. But he didn't say when the correct value for the branching ratio began to be used. Even some figures from Faure, Principles of Isotope Geology, are based on another constant that is 2 or 3 percent too low, according to Dalrymple, and so there may be many ages in the literature that need revision by small amounts.
However, Harland et al imply that nearly the correct value for the branching ratio has been known and used since the mid-fifties. We now consider whether they can explain the observed dates. In general, the dates that are obtained by radiometric methods are in the hundreds of millions of years range.
One can understand this by the fact that the clock did not get reset if one accepts the fact that the magma "looks" old, for whatever reason. That is, we can get both parent and daughter elements from the magma inherited into minerals that crystallize out of lava, making these minerals look old.
Since the magma has old radiometric dates, depending on how much the clock gets reset, the crust can end up with a variety of younger dates just by partially inheriting the dates of the magma.
Thus any method based on simple parent to daughter ratios such as Rb-Sr dating is bound to be unreliable, since there would have to be a lot of the daughter product in the magma already. And Harold Coffin's book Creation by Design lists a study showing that Rb-Sr dates are often inherited from the magma. Even the initial ratios of parent and daughter elements in the earth do not necessarily indicate an age as old as 4. Radioactive decay would be faster in the bodies of stars, which is where scientists assume the heavy elements formed.
Imagine a uranium nucleus forming by the fusion of smaller nucleii. At the moment of formation, as two nucleii collide, the uranium nucleus will be somewhat unstable, and thus very likely to decay into its daughter element.
The same applies to all nucleii, implying that one could get the appearance of age quickly. Of course, the thermonuclear reactions in the star would also speed up radioactive decay.
But isochrons might be able to account for pre-existing daughter elements. Furthermore, some elements in the earth are too abundant to be explained by radioactive decay in 4. Some are too scarce such as helium. So it's not clear to me how one can be sure of the 4. Why older dates would be found lower in the geologic column especially for K-Ar dating In general, potassium-argon dates appear to be older the deeper one goes in the crust of the earth.
We now consider possible explanations for this. There are at least a couple of mechanisms to account for this. In volcano eruptions, a considerable amount of gas is released with the lava. This gas undoubtedly contains a significant amount of argon Volcanos typically have magma chambers under them, from which the eruptions occur. It seems reasonable that gas would collect at the top of these chambers, causing artificially high K-Ar radiometric ages there.
In addition, with each successive eruption, some gas would escape, reducing the pressure of the gas and reducing the apparent K-Ar radiometric age.
Thus the decreasing K-Ar ages would represent the passage of time, but not necessarily related to their absolute radiometric ages. As a result, lava found in deeper layers, having erupted earlier, would generally appear much older and lava found in higher layers, having erupted later, would appear much younger.
This could account for the observed distribution of potassium-argon dates, even if the great sedimantary layers were laid down very recently. In addition, lava emerging later will tend to be hotter, coming from deeper in the earth and through channels that have already been warmed up. This lava will take longer to cool down, giving more opportunity for enclosed argon to escape and leading to younger radiometric ages. Another factor is that rocks absorb argon from the air. It is true that this can be accounted for by the fact that argon in the air has Ar36 and Ar40, whereas only Ar40 is produced by K-Ar decay.
But for rocks deep in the earth, the mixture of argon in their environment is probably much higher in Ar40, since only Ar40 is produced by radioactive decay. As these rocks absorb argon, their radiometric ages would increase.
This would probably have a larger effect lower down, where the pressure of argon would be higher. Or it could be that such a distribution of argon pressures in the rocks occurred at some time in the past.
This would also make deeper rocks tend to have older radiometric ages. Recent lava flows often yield K-Ar ages of about , years. This shows that they contain some excess argon, and not all of it is escaping.
If they contained a hundred times more excess argon, their K-Ar ages would be a hundred times greater, I suppose. And faster cooling could increase the ages by further large factors. I also read of a case where a rock was K-Ar dated at 50 million years, and still susceptible to absorbing argon from the air.
This shows that one might get radiometric ages of at least 50 million years in this way by absorbing Ar40 deep in the earth without much Ar36 or Ar38 present. If the pressure of Ar40 were greater, one could obtain even greater ages. Yet another mechanism that can lead to decreasing K-Ar ages with time is the following, in a flood model: One can assume that at the beginning of the flood, many volcanoes erupted and the waters became enriched in Ar Then any lava under water would appear older because its enclosed Ar40 would have more trouble escaping.
As time passed, this Ar40 would gradually pass into the atmosphere, reducing this effect and making rocks appear younger.
In addition, this would cause a gradient of Ar40 concentrations in the air, with higher concentrations near the ground. This also could make flows on the land appear older than they are, since their Ar40 would also have a harder time escaping. Plaisted wants to give his readers the impression that argon can readily move in and out of minerals and, therefore, the gas is too volatile for radiometric dating.
Specifically, he quotes one of his anonymous friends that claims that argon easily diffuses from minerals p. Of course, these statements are inaccurate generalizations. Geochronologists are aware that excess argon may accumulate on mineral surfaces and the surface argon would be removed before analysis. However, Henke admits that this can happen in some cases. He states that geologists are aware of this problem, and make allowances for it. But it is more difficult to remove argon that has deposited on cracks in the mineral, which can be difficult to see.
Henke referenced Davis A. Young frequently, but I was not able to find Young referenced in any of the other sources I examined except Dalrymple Henke states that hornblendes retain argon very well, but then later says that they can easily absorb excess argon. Geologists also recognize that heating causes argon to leave minerals, and that dissolved argon in a mineral that does not escape will become incorporated into it, artificially increasing its K-Ar age.
I will comment more on this below, but a few comments now are appropriate. For a temperature of K 27 degrees C , there is no significant argon loss from biotite. At K degrees C , there is a slow but significant diffusion rate.
At K degrees C , loss of argon is quite rapid. To lose one percent in one year requires a temperature of nearly degrees centigrade. Thus the temperature does not have to be very high for argon to move through rock. This also justifies Slusher's statements about argon moving in and out of rocks with ease. However, it does not seem likely that sedimentary rocks would be this hot very often, except near lava or magma flows.
But argon does not need to move through all rock in order to influence radiometric dates, it only has to reach ancient lava flows. This it can do by following the path of the ancient lava flow itself, coming up along the path of the magma. As the magma or lava cools, this path will consist entirely of hot magma or lava, and so the argon will have a free path, and will continue to enter the magma as it cools.
Thus in many cases, the lava or magma will never completely degas, and extra argon will end up trapped in the cooled rock. This will result in artificially increased K-Ar ages. Many ancient lava flows are relatively flat, in contrast to modern ones.
Also, they appear to have been covered over quickly. The flatness means that the lava is a contiguous mass, and can still be reached from the hot magma by a continuous path of hot rock.
The fact that they soon are covered over means that the argon has a hard time escaping vertically from the lava, so argon coming up from the mantle will tend to enter the cooling rock. Both facts will tend to produce artificially high K-Ar ages in these flows which will not be seen in modern lava flows in the same manner. Modern lava flows often come down the sides of volcanoes, and thus become separated from their source by large distances. Also, they do not get quickly buried by additional sediment.
Thus modern lava flows are not subject to the same mechanism of artificial increases in their K-Ar ages as are ancient ones. Also, it is reasonable to assume that as argon leaves the mantle in successive eruptions, the amount of argon remaining is reduced, so that later lava flows are less susceptible to such artificial increases in age.
The path of magma also becomes longer for later flows, and the magma probably also is a little cooler, inhibiting argon flow.
Thus later lava flows give younger K-Ar ages. Another point to note is that even after it cools, the lava or magma may still have many cracks in it, permitting argon to flow. This argon will tend to deposit on the surface of minerals, but with the passage of time it will tend to diffuse into the interior, even if only a very small distance. This is especially true as the lava is cooling. This will make it more difficult to detect this added argon by the spectrum test described below.
Also, the diffusion of argon in cracks and channels of a mineral is likely much less temperature-dependent than diffusion through unbroken regions of the mineral, since diffusion through cracks and channels simply involves jumps through the air. By a combination of diffusion through cracks and channels, and short passages through unbroken regions of the mineral, argon may be able to reach a considerable distance into the mineral.
At low temperatures, this may become the dominant means by which argon diffuses into a mineral, but the effect of this kind of diffusion at low temperatures may not be evident until many years have passed.
Thus it may take experiments lasting 50 or years at low temperatures to detect the effects of this kind of diffusion of argon, which however could be significantly increasing the K-Ar ages of minerals over long time periods. Dickin Radiogenic Isotope Geology, , p.
It has been claimed that this can be accomplished by preheating samples under vacuum or by leaching them briefly with hydroflouric acid, or both However Armstrong has questioned whether atmospheric argon, that has been acquired by minerals over a long interval of time, can be removed by this method.
Thus there is some means by which argon from outside can become very firmly embedded within a rock, and one would expect that the quantity of this argon would continue to increase over time, giving anomalously old K-Ar ages. Added atmospheric argon can be detected, because the ratio of argon 40 to argon 36 for atmospheric argon is But argon 40 coming up from the mantle and diffusing into a mineral would not be detectable in this way, because it has a higher ratio of argon 40 to argon This shows that rocks can adsorb a large amount of argon relative to the argon needed to give them old K-Ar ages, and also suggests that old K-Ar ages can be produced by external argon from the mantle.
Over a long period of time, adsorbed argon will tend to diffuse into the rock, and thus it will be possible for even more argon to be deposited on the surface, increasing K-Ar ages even more. Generally, excess 40Ar is observed in minerals that have been exposed to a high partial pressure of argon during regional metamorphism, in pegmatites The argon that may either diffuse into the minerals or may be occluded within them is derived by outgassing of K-bearing minerals in the crust and mantle of the Earth.
The presence of excess 40Ar increases K-Ar dates and may lead to overestimates of the ages of minerals dated by this method. Let us consider the question of how much different dating methods agree on the geologic column, and how many measurements are anomalous, since these points are often mentioned as evidences of the reliability of radiometric dating.
It takes a long time to penetrate the confusion and find out what is the hard evidence in this area. In the first place, I am not primarily concerned with dating meteorites, or precambrian rocks. What I am more interested in is the fossil-bearing geologic column of Cambrian and later age. Now, several factors need to be considered when evaluating how often methods give expected ages on the geologic column. Some of these are taken from John Woodmoreappe's article on the subject, but only when I have reason to believe the statements are also generally believed.
First, many igneous formations span many periods, and so have little constraint on what period they could belong to. The same applies to intrusions. In addition, some kinds of rocks are not considered as suitable for radiometric dating, so these are typically not considered. Furthermore, it is at least possible that anomalies are under-reported in the literature. Finally, the overwhelming majority of measurements on the fossil bearing geologic column are all done using one method, the K-Ar method.
And let me recall that both potassium and argon are water soluble, and argon is mobile in rock. Thus the agreement found between many dates does not necessarily reflect an agreement between different methods, but rather the agreement of the K-Ar method with itself.
For example, if 80 percent of the measurements were done using K-Ar dating, and the other 20 percent gave random results, we still might be able to say that most of the measurements on a given strata agree with one another reasonably well. So to me it seems quite conceivable that there is no correlation at all between the results of different methods on the geologic column, and that they have a purely random relationship to each other.
Let us consider again the claim that radiometric dates for a given geologic period agree with each other. I would like to know what is the exact or approximate information content of this assertion, and whether it could be or has been tested statistically. It's not as easy as it might sound. Let's suppose that we have geologic periods G Let's only include rocks whose membership in the geologic period can be discerned independent of radiometric dating methods. Let's also only include rocks which are considered datable by at least one method, since some rocks I believe limestone are considered not to hold argon, for example.
Now, we can take a random rock from Gi. We will have to restrict ourselves to places where Gi is exposed, to avoid having to dig deep within the earth. Let's apply all known dating methods to Gi that are thought to apply to this kind of rock, and obtain ages from each one. Then we can average them to get an average age for this rock. We can also compute how much they differ from one another.
Now we have to be careful about lava flows -- which geologic period do they belong to? What about rocks that are thought not to have their clock reset, or to have undergone later heating episodes?
Just to make the test unbiased, we will assign altitude limits to each geologic period at each point on the earth's surface at least in principle and include all rocks within these altitude limits within Gi, subject to the condition that they are datable.
For each geologic period and each dating method, we will get a distribution of values. We will also get a distribution of averaged values for samples in each period. Now, some claim is being made about these distributions. It is undoubtedly being claimed that the mean values ascend as one goes up the geologic column. It is also being claimed that the standard deviations are not too large.
It is also being claimed that the different methods have distributions that are similar to one another on a given geologic period. The only correlation I know about that has been studied is between K-Ar and Rb-Sr dating on precambrian rock. And even for this one, the results were not very good.
This was a reference by Hurley and Rand, cited in Woodmorappe's paper. As far as I know, no study has been done to determine how different methods correlate on the geologic column excluding precambrian rock. The reason for my request is that a correlation is not implied by the fact that there are only 10 percent anomalies, or whatever. I showed that the fact that the great majority of dates come from one method K-Ar and the fact that many igneous bodies have very wide biostratigraphic limits, where many dates are acceptable, makes the percentage of anomalies irrelevant to the question I am asking.
And since this agreement is the strongest argument for the reliability of radiometric dating, such an assumption of agreement appears to be without support so far. The question of whether different methods correlate on the geologic column is not an easy one to answer for additional reasons.
Since the bulk of K-Ar dates are generally accepted as correct, one may say that certain minerals are reliable if they tend to give similar dates, and unreliable otherwise. We can also say that certain formations tend to give reliable dates and others do not, depending on whether the dates agree with K-Ar dates. Thus we can get an apparent correlation of different methods without much of a real correlation in nature. It's also possible for other matter to be incorporated into lava as it rises, without being thoroughly melted, and this matter may inherit all of its old correlated radiometric dates.
Coffin mentions that fission tracks can survive transport through lava, for example. It may also be that lava is produced by melting the bottom of continents and successively different layers are melted with time, or there could be a tendency for lighter isotopes to come to the top of magma chambers, making the lava there appear older.
But anyway, I think it is important really to know what patterns appear in the data to try to understand if there is a correlation and what could be causing it. Not knowing if anomalies are always published makes this harder. It is often mentioned that different methods agree on the K-T boundary, dated at about 65 million years ago. This is when the dinosaurs are assumed to have become extinct.
This agreement of different methods is taken as evidence for a correlation between methods on the geologic column. One study found some correlated dates from bentonite that are used to estimate the date of the K-T boundary. I looked up some information on bentonite. It is composed of little glass beads that come from volcanic ash.
This is formed when lava is sticky and bubbles of gas in it explode. So these small particles of lava cool very fast. The rapid cooling might mean that any enclosed argon is retained, but if not, the fact that this cooling occurs near the volcano, with a lot of argon coming out, should guarantee that these beads would have excess argon. As the gas bubble explodes, its enclosed argon will be rushing outward along with these tiny bubbles as they cool.
This will cause them to retain argon and appear too old. In addition, the rapid cooling and the process of formation means that these beads would have Rb, Sr, U, and Pb concentrations the same as the lava they came from, since there is no chance for crystals to form with such rapid cooling. So to assume that the K-Ar dates, Rb-Sr dates, and U-Pb dates all reflect the age of the lava, one would have to assume that this lava had no Sr, no Pb, and that all the argon escaped when the beads formed.
Since the magma generally has old radiometric ages, I don't see how we could have magma without Pb or Sr. So to me it seems to be certain that these ages must be in error. Furthermore, the question arises whether bentonite always gives correlated ages, and whether these ages always agree with the accepted ages for their geologic period.
I believe that bentonite occurs in a number of formations of different geologic periods, so this could be checked. If bentonite does not always give correlate and correct ages, this calls into question its use for dating the K-T boundary. Let me briefly comment on a couple of other articles at Tim Thompson's page. This is at least close to what I am looking for. However, it would be better to date all five craters by all four different methods, and see what the agreement is.
It is also possible that each crater gives a scatter of dates, and the best ones were selected. Furthermore, it is possible that the craters were chosen as those for which the dating methods agreed. Possible other sources of correlation Note that if there are small pockets in crystals where both parent and daughter product can accumulate from the lava, then one can inherit correlated ages from the lava into minerals. Thus even the existence of correlations is not conclusive evidence that a date is correct.
Anomalies of radiometric dating If a date does not agree with the expected age of its geologic period, and no plausible explanation can be found, then the date is called anomalous. But if we really understand what is going on, then we should be able to detect discrepant dates as they are being measured, and not just due to their divergence from other dates. Geologists often say that the percentage of anomalies is low.
But there are quite a number of rather outstanding anomalies in radiometric dating that creationists have collected. These anomalies are reported in the scientific literature. For example, one isochron yielded a date of 10 billion years. A Rb-Sr isochron yielded a date of 34 billion years. K-Ar dates of 7 to 15 billion years have been recorded. It's also not uncommon for two methods to agree and for the date to be discarded anyway. Samples with flat plateaus which should mean no added argon can give wrong dates.
Samples giving no evidence of being disturbed can give wrong dates. Samples that give evidence of being disturbed can give correct dates. The number of dates that disagree with the expected ages is not insignificant.
I don't know what the exact percentage is. Many dates give values near the accepted ones. But even these often differ from one another by 10 or 20 percent. And quite a few other dates are often much, much farther off. Whatever is making some of these dates inaccurate could be making all of them inaccurate. Age estimates on a given geological stratum by different radiometric methods are often quite different sometimes by hundreds of millions of years.
There is not absolutely reliable long-term radiological "clock". The uncertainties inherent in radiometric dating are disturbing to geologists and evolutionists As proof of the unreliability of the radiometric methods consider the fact that in nearly every case dates from recent lava flows have come back excessively large. One example is the rocks from the Kaupelehu Flow, Hualalai Volcano in Hawaii which was known to have erupted in These rocks were dated by a variety of different methods.
Of 12 dates reported the youngest was million years and the oldest was 2. The dates average 1. Another source said that about 5 or 6 of the historic lava flows give ages in the hundreds of thousands of years. Geologists explain the Kaupelehu date by the lava being cooled rapidly in deep ocean water and not being able to get rid of its enclosed argon. Instead, the uncertainty grows as more and more data is accumulated Woodmorappe also mentions that very self-contradictory age spreads in the Precambrian era are common.
In addition, Woodmorappe gives over sets of dates "that are in gross conflict with one another and with expected values for their indicated paleontological positions. This does not include dates from minerals that are thought to yield bad dates, or from igneous bodies with wide biostrategraphic ranges, where many dates are acceptable.
He states that the number of dates within range are less than the number of anomalies, except for the Cenozoic and Cretaceous. When one adds in the fact that many anomalies are unreported, which he gives evidence for, the true distribution is anyone's guess. There have been criticisms of John Woodmorappe's study, but no one has given any figures from the literature for the true percentage of anomalies, with a definition of an anomaly, or the degree of correlation between methods. Steven Schimmrich's review of this study often concerns itself with John W's presentation of geologists explanation for anomalies, and not with the percentage of anomalies; the later is my main concern.
The carbon age of the buried trees is only years, but some of the overlying volcanic material has a ,year potassium-argon age. A similar situation is reported in the December issue of Creation ex nihilo in which lava with a K-Ar age of about 45 million years overlays wood that was carbon dated by 3 laboratories using AMS dating to about 35, years.
Still another evidence for problems with radiometric dating was given in a recent talk I attended by a man who had been an evolutionist and taken a course in radiometric dating. The teacher gave 14 assumptions of radiometric dating and said something like "If creationists got a hold of these, they could cut radiometric dating to pieces. Another evidence that all is not well with radiometric dating is given in the following quote from Coffin p.
Many sedimentary uranium ores are not. Since equilibrium should be reached in 1 million years, this is a problem for sediments that are assumed to be older than 1 million years. On another point, if we can detect minerals that were not molten with the lava, as has been claimed, then this is one more reason why there should be no anomalies, and radiometric dating should be a completely solved problem.
But that does not appear to be the case, at least especially on the geologic column. I'm not claiming that anomalous results are being hidden, just that the agreement of a mass of results, none of which has much claim to reliability, does not necessarily mean much. Picking out a few cases where radiometric dates appear to be well-behaved reminds me of evolutionary biologists focusing on a few cases where there may be transitional sequences.
It does not answer the overall question. And as I said above, I'm also interested to know how much of the fossil-bearing geologic column can be dated by isochrons, and how the dates so obtained compare to others. Gerling et al called attention to some chlorites yielding K-Ar dates of 7 to 15 b. It had been noted that some minerals which yield such dates as beryl, cordierite, etc. They also pointed out that for the anomalies to be accounted for by excess argon, unreasonably high partial pressures of Ar during crystallization would have to be required.
They concluded by suggesting some unknown nuclear process which no longer operates to have generated the Ar. This implies that excess argon is coming from somewhere. Here is another quote from Woodmorappe about isochrons, since some people think that mixing scenarios or other age-altering scenarios are unlikely:. If this condition does not hold, invalid ages and intercepts are obtained. Models yield isochron ages that are too high, too low, or in the future, sometimes by orders of magnitude.
The fact that the only "valid" K-Ar isochrons are those for which the concentration of non-radiogenic argon Ar36 is constant, seems very unusual.
This suggests that what is occuring is some kind of a mixing phenomenon, and not an isochron reflecting a true age. We have analyzed several devitrified glasses of known age, and all have yielded ages that are too young. Some gave virtually zero ages, although the geologic evidence suggested that devitrification took place shortly after the formation of a deposit.
Why a low anomaly percentage is meaningless One of the main arguments in favor of radiometric dating is that so many dates agree with each other, that is, with the date expected for their geologic period.
But it's not evident how much support this gives to radiometric dating. If a rock dates too old, one can say that the clock did not get reset. If it dates too young, one can invoke a later heating event. Neither date would necessarily be seen as anomalous. If lava intrudes upon geologic period X, then any date for the lava of X or later will not be seen as anomalous. And even if the date is one or two geologic periods earlier, it may well be close enough to be accepted as non-spurious.
If one does not know the geologic period of a rock by other means, then of course one is likely to date it to find out, and then of course the date agrees with the geologic period and this will not be seen as anomalous. So it is difficult to know what would be a reasonable test for whether radiometric dating is reliable or not. The percentage of published dates that are considered as anomalous has little bearing on the question.
The biostrategraphic limits issue The issue about igneous bodies may need additional clarification. If a lava flow lies above geologic period A and below B, then allowable ages are anything at least as large as A and no larger than B. This is called the biostratigraphic limit of the flow. Now, according to Woodmorappe's citations, many lava flows have no such limits at all, and most of them have large limits.
For example, a flow lying on precambrian rock with nothing on top would have no limits on its dates. And such flows often have a large internal scatter of dates, but these dates are not considered as anomalies because of the unrestricted biostratigraphic limit. Other flows with wide biostratigraphic limits have weak restrictions on allowable dates. This is one reason why just reporting the percentage of anomalies has little meaning. Thus these ages, though they generally have a considerable scatter, are not considered as anomalies.
He cites another reference that most igneous bodies have wide biostrategraphic limits. Thus just by chance, many dates will be considered within the acceptable ranges. Again, the percentage of anomalies means nothing for the reliability of radiometric dating. Now, igneous bodies can be of two types, extrusive and intrusive. Extrusive bodies are lava that is deposited on the surface. These cool quickly and have small crystals and form basalt.
Intrusive bodies are deposited in the spaces between other rocks. These cool more slowly and have larger crystals, often forming granite. Both of these tend on the average to have wide biostrategraphic limits, meaning that a large spread of ages will be regarded as non-anomalous. And if we recall that most radiometric dating is done of igneous bodies, one sees that the percentage of anomalies is meaningless.
Thus we really need some evidence that the different methods agree with each other. To make the case even stronger, "Many discrepant results from intrusives are rationalized away immediately by accepting the dates but reinterpreting the biostrategraphic bracket," according to John Woodmorappe.
This of course means that the result is no longer anomalous, because the geologic period has been modified to fit the date. Finally, the fact that the great majority of dates are from one method means that the general but not universal agreement of K-Ar dating with itself is sufficient to explain the small percentange of anomalies if it is small.
Preponderance of K-Ar dating Now, the point about agreement is that whatever figure is given about how often ages agree with the expected age, is consistent with the fact that there is no agreement at all between K-Ar and other methods, since so many measurements are done using K-Ar dating.
And one of the strongest arguments for the validity of radiometric dating is that the methods agree. So when one combines all of the above figures, the statement that there are only 10 percent anomalies or 5 percent or whatever, does not have any meaning any more. This statement is made so often as evidence for the reliability of radiometric dating, that the simple evidence that it has no meaning, is astounding to me. I don't object to having some hard evidence that there are real agreements between different methods on the geologic column, if someone can provide it.
The precambrian rock is less interesting because it could have a radiometric age older than life, but this is less likely for the rest of the geologic column. It's not surprising that K-Ar dates often agree with the assumed dates of their geological periods, since the dates of the geological periods were largely inferred from K-Ar dating. By the way, Ar-Ar dating and K-Ar dating are essentially the same method, so between the two of them we obtain a large fraction of the dates being used.
Before the discovery of radioactivity in the late nineteenth century, a geological time scale had been developed on the basis of estimates for the rates of geological processes such as erosion and sedimentation, with the assumption that these rates had always been essentially uniform. On the basis of being unacceptably old, many geologists of the time rejected these early twentieth century determinations of rock age from the ratio of daughter to radioactive parent large.
By , increased confidence in radioisotope dating techniques and the demands of evolution theory for vast amounts of time led to the establishment of an expanded geological time scale. The construction of this time scale was based on about radioisotope ages that were selected because of their agreement with the presumed fossil and geological sequences found in the rocks.
Igneous rocks are particularly suited to K-Ar dating. The crucial determiners are therefore volcanic extrusive igneous rocks that are interbedded with sediments, and intrusive igneous rocks that penetrate sediments. This verifies what I said about almost all of the dates used to define correct ages for geologic periods being K-Ar dates.
Also, the uncertainty in the branching ratio of potassium decay might mean that there is a fudge factor in K-Ar ages of up to a third, and that the occasional agreements between K-Ar ages and other ages are open to question. So the point is that there is now no reason to believe that radiometric dating is valid on the geologic column.
I mentioned the presence of excess argon 40 in a sample as a problem leading to artificially old K-Ar dates. Henke states in a reply to me, concerning the problem of detecting excess argon,. It is possible that such isochrons are not often done. One cannot always use an isochron, since many minerals may have about the same K and Ar40 concentrations, and there may be some fractionation of argon among the minerals.
It's not clear to me if this three dimensional plot always works, and how often it is used. I was not able to find any mention of it in Faure or Dickin It is true that by using additional isotopes if they are sufficiently abundant and do not fractionate , one can often detect mixings of multiple sources. My point was that the usual mixing test can only detect two sources. But since these multiple mixing tests are more difficult and expensive, they may not be done very often.
One also has to know which isotopes to examine. I was suprised that Dalrymple said nothing about mixings invalidating isochrons. Dalrymple goes to great lengths to explain this away, but I think this figure is very telling, and find his explanations unconvincing.
It is also remarkable that we have a test for mixing, which is commonly cited in support of the accuracy of radiometric dating, but when it gives contrary results, it is simply ignored. It is a fundamental assumption of the mantle isochron model that neither isotope nor elemental ratios are perturbed during magma ascent through the crust. However, it is now generally accepted that this assumption is not upheld with sufficient reliability to attribute age significance to erupted isochrons.
Dickin suggests that mixings may contribute to such isochrons. It seems reasonable, then, that mixings may be affecting all Rb-Sr isochrons in igneous rock. Your hypothetical example in "More Bad News for Radiometric Dating" is often hard to follow, but it is clearly invalid. This example is given to show that a mixing of three sources cannot be detected by the usual two sources test. It is not intended to be natural, but to demonstrate a mathematical fact. There is a lot of flexibility in the design of such examples, as I indicate, and it is reasonable to assume that some of these examples would be natural.
It's the responsibility of the geologist to show that such mixings have not occurred. To really understand what's going on you have to sample the recent works of many different authors. You have to follow arguments between experts on different issues and see where they go. Overall, the geologic time scale is in great shape. Yes, scientists are still making minor adjustments. However, it's clear from Strahler , Dalrymple , etc. The problem with this approach is that it leaves ample room for the exercise of subjective judgment and evolutionary assumptions.
Also, Dalrymple says essentially nothing about the phanerozoic, and thus gives little evidence of the accuracy of the conventional dating scheme on fossil-bearing rocks. I treated this issue of percentage of anomalies in considerable detail in my original "Radiometric Dating Game" article.
It is interesting that Woodmorappe gives a number of cases in which standard geological tests are ignored. For example, dates may be accepted even when there is evidence of weathering, and rejected when there is not. There may be evidence of heating, but the date may be accepted, and there may be no such evidence, but a hypothetical heating event is assumed anyway. If geological tests are not being applied consistently, one wonders what value they have.
Let me clarify the problem with excess argon. It gives the diffusion equation for argon escaping from a rock as it cools. The rate of diffusion is proportional to the gradient of argon concentration, and increases rapidly with temperature. Suppose the partial pressure of argon 40 in the environment is p.
Imsges: carbon 14 is not useful for dating most fossils because
As for the other methods, some minerals when they form exclude daughter products.
Dinosaur bones do not have carbon unless contaminated , as the dinosaurs became extinct over 60 million years ago.
What is Carbon Dating? Specifically, he quotes one of his anonymous friends that claims that argon easily diffuses from minerals p. The dating carbon 14 is not useful for dating most fossils because provided by radiocarbon led to a change in the prevailing view of how beccause spread through prehistoric Europe. This rather damaging result was explained away saying that enough evidence of correct radii for defferent geologic periods and sufficient variation in the same period have been obtained that one is forced to look for a different explanation of such variations as were observed by Joly. Introduction to evolution Common descent Phylogeny Cladistics Biological classification. We have covered a lot of convincing evidence that the Earth was created a very long time ago.
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