At the time that Darwin's On the Origin of Species was published, the earth was "scientifically" determined to be 100 million years old. By 1932, it was found to be 1.6 billion years old. In 1947, geologists firmly established that the earth was 3.4 billion years old. Finally in 1976, they discovered that the earth is "really" 4.6 billion years old… What happened? 4
The study of geology grew out of field studies associated with mining and engineering during the sixteenth to nineteenth centuries. In these early studies the order of sedimentary rocks and structures were used to date geologic time periods and events in a relative way. At first, the use of “key” diagnostic fossils was used to compare different areas of the geologic column. Although there were attempts to make relative age estimates, no direct dating method was available until the twentieth century.
Following the discovery of radioactivity by Becquerel (1896), the possibility of using this phenomenon as a means for determining the age of uranium-bearing minerals was demonstrated by Rutherford (1906). In his study Rutherford measured the U and He (He is an intermediate decay product of U) contents of uranium-bearing minerals to calculate an age. One year later Boltwood (1907) developed the chemical U-Pb method. These first “geochronology studies” yielded the first “absolute ages” from geologic material, which seemed to indicate that parts of the Earth's crust were hundreds of millions of years old. (Boltwood's ages have since been revised).
During this same period of time Thomson (1905), Campbell and Wood (1906) demonstrated that potassium was radioactive and emitted beta-particles. The first isotopes of potassium (39K and 41K) were reported by Aston (1921). Kohlhorster (1930) reported that potassium also emitted gamma radiation. Following theoretical arguments by Klemperer, Newman and Walke (1935) on the existence of 40K, which radioactively decayed to 40Ca by beta-emission, Nier (1935) discovered 40K and reported a value of 8600 for the 39K/40K ratio. Newman and Walke also suggested the possibility that 40K could decay to 40Ar. However, it was Von Weizsacker's (1937) argument, based on the abundance of argon in the Earth's atmosphere relative to the other noble gases (He, Ne, Kr, and Xe), that 40K also decayed to 40Ar by electron capture. As a test, Von Weizsacker suggested looking for excess 40Ar in older K-bearing rocks. By combining Von Weizsacker’s argon abundance arguments with Kohlhorster’s observation that potassium emitted gamma-radiation, Bramley (1937) presented strong evidence that potassium underwent dual decay. Thompson and Rowlands (1943), using a cloud chamber, confirmed that 40Ar was the decay product of 40K undergoing electron capture. The absolute confirmation that 40Ar was the decay product of 40K came when Aldrich and Nier (1948) measured significantly increased 40Ar/36Ar ratios on argon extracted from potassium-rich minerals relative to the atmospheric 40Ar/36Ar ratio. The rapid development of the K-Ar dating method soon followed.
The 40Ar/39Ar variation of K-Ar dating grew out of iodine-xenon dating studies of meteorites by Jeffery and Reynolds (1961). In these studies the isotopic ratios of all the noble gases (He, Ne, Ar, Kr, and Xe) of neutron-irradiated meteorites were measured. This led to the discovery of 39Ar, which is derived from 39K by Merrihue (1965). The first 40Ar/39Ar dating results were presented in a paper by Merrihue and Turner (1966). Further development of the 40Ar/39Ar method by Mitchell, (1968), Brereton, (1970), and Turner, (1971) evaluated the interfering argon isotopes derived from potassium and calcium (36ArCa, 39ArCa, and 40ArK) and determination of the respective correction factors [ (36Ar/37Ar)Ca, (39Ar/37Ar)Ca, and (40Ar/39Ar)K]. The first applications of the 40Ar/39Ar dating method of terrestrial rocks compared total fusion 40Ar/39Ar ages with conventional K-Ar ages (Mitchell, 1968; Dunham et al., 1968; York and Berger, 1970; Dalrymple and Lanphere, 1971).
It is felt that the 40Ar/39Ar dating method offers a significant advantage over the conventional 40K/40Ar dating technique for several reasons. However, the most significant advantage of the 40Ar/39Ar dating method over the conventional 40K/40Ar method is the ability to step-heat samples to higher and higher temperatures until the sample is fused, and calculate and ages for each step. The 40Ar/39Ar step-heating method provides information on the internal distribution of potassium relative to argon. The first 40Ar/39Ar step-heating studies of terrestrial samples were by Fitch (1969), Miller (1970), York (1971), Lanphere and Dalrymple (1971), and Brereton (1972).
Assumptions [/siz]
Dating rocks by radioactive timekeepers is simple in theory, but all of the different methods rely on a few basic assumptions:
Beginning Conditions Known
Beginning Ratio of Daughter to Parent Isotope Known
Constant Decay Rate
No Leaching or Addition of Parent or Daughter Isotopes
All Assumptions Valid for Billions of Years
There is also a difficulty in measuring precisely very small amounts of the various isotopes
Interweaving the relative time scale with the atomic time scale poses certain problems because only certain types of rocks, chiefly the igneous variety, can be dated directly by radiometric methods; but these rocks do not ordinarily contain fossils. Igneous rocks are those such as granite and basalt, which crystallize from molten material called "magma". There is even some valid question as to if granite could be formed from magma at all since this has never been observed or duplicated in the lab. Radio-halos from rapidly decaying radioactive isotopes in granite seem to indicate that the granites were formed almost instantly.
Most sedimentary rocks such as sandstone, limestone, and shale (which do contain fossils) are related to the radiometric time scale by bracketing them within time zones that are determined by dating appropriately selected igneous rocks in lava flows, or weathered from lava flows.
Potassium - Argon and Argon - Argon dating is based on the current understanding that radioactive Potassium-40 decays to the stable form, Argon-40 with a half-life of approximately 1.25 billion years. The same principle holds true for the other isotope “dating” methods.
Radioactive decay occurs at a constant exponential or geometric rate. The rate of decay is proportional to the number of parent atoms present. There are some circumstances that can affect this rate such as magnetic fluctuations etc... But in general, this seems to be a constant.
If one starts with an originally pure sample of “parent element,” then the proportion of parent to daughter tells us the number of half-lives, which has been used to find the supposed age of igneous rocks. For example, if there are equal amounts of parent and daughter isotopes, then one half-life has passed. If there are three times as many daughter isotopes as parent, then two half-lives have passed, and so on.
Most minerals, which contain radioactive isotopes, are in igneous rocks. The majority of scientists today assume that the dates they give indicate the time the magma cooled. This also assumes that there was no initial daughter isotopes contained in the magma at the time of cooling. The assumption is that at least a great majority of the isotope present was the parent isotope. This parent isotope then degraded to the daughter isotope over time. Consider the following statement by Dalrymple, a well-known geologist:
"The K-Ar method is the only decay scheme that can be used with little or no concern for the initial presence of the daughter isotope. This is because 40Ar is an inert gas that does not combine chemically with any other element and so escapes easily from rocks when they are heated. Thus, while a rock is molten, the 40Ar formed by the decay of 40K escapes from the liquid."
So, according to Dalrymple, K-Ar or Ar-Ar are the only methods that have little or no concern for the presence of initial daughter isotopes. This means that all the other radioisotope-dating methods are brought into serious question. The reason for this is because unless the initial ratio of parent to daughter isotope is known, the current ratio would be worthless as a means of determining elapsed time. A rock cannot be said to be millions or billions of years old if there is no way of knowing what the original composition of the rock was at the time that it was formed. The assumption for the K-Ar method is that all argon escapes at the time of rock formation because argon is a gas while potassium is not. The other dating methods such as uranium-lead cannot use this neat little method of determining the original composition of a given rock as it formed. Because of this problem, it might be a significant error to simply assume that all original isotopes present in a given rock were parent isotopes.
Lets now consider how fossils are dated. The mineralized fossils themselves are not directly datable by radiometric techniques. The sedimentary rock that buried them is also not datable. If there is some igneous rock fragments in that sedimentary rock layer, these fragments are dated, most commonly, by the 40K/40Ar dating method described above. It is assumed then that the fossil is as old as the igneous rock fragment that it is buried with. Aside from the zero-date problems noted above, one might consider the possibility that the fossil might not be as old as the sediment that buried it in the first place. For example, lets say that my pet dog dies. I decide to bury it in the back yard. Is the dog as old as the dirt that I buried it in? Likewise, who is to say that some fossils were not buried in sedimentary material that was weathered from significantly more ancient formations?
Potassium-Argon and Argon-Argon[/siz]
Since Potassium-Argon and Argon-Argon dating techniques are the most common and are considered, even by geologists, to be the most accurate of all the radioisotope dating methods, lets consider these in particular detail.
Argon is a noble gas. The main isotopes of argon in terrestrial systems are 40Ar (99.6%), 36Ar (0.337%), and 38Ar (0.063%). Naturally occurring 40K decays to stable 40Ar (11.2%) by electron capture and by positron emission, and decays to stable 40Ca (88.8%) by negatron emission; 40K has a half-life of 1.25 billion years.
Most of the argon isotope literature deals with measurement of 40Ar for use in 40K/40Ar dating of rocks. The conventional 40K/40Ar dating method depends on the assumption that the rocks contained no argon at the time of formation and that all the subsequent radiogenic argon (i.e., 40Ar) was quantitatively retained. Minerals are dated by measurement of the concentration of potassium, and the amount of radiogenic 40Ar that has accumulated. The minerals that are best suited for dating include biotite, muscovite, and plutonic/high grade metamorphic hornblende, and volcanic feldspar; whole rock samples from volcanic flows and shallow instrusives can also be dated if they are unaltered (Faure, 1986).
Under some circumstances the requirements for successful 40K/40Ar dating may be violated. For example, if 40Ar is lost by diffusion while the rock cooled, the age-dates represent the time elapsed since the rock cooled sufficiently for diffusive losses to be insignificant. Or, if excess 40Ar is present in the rock, the calculated age-dates are too old. The 40Ar/39Ar method is thought to be able to overcome this problem inherent with the 40K/40Ar method.
The 40Ar/39Ar dating method is based on the formation of 39Ar as a result of the intentional irradiation of K-bearing samples within a nuclear reactor. The bombardment produces various isotopes of Ar, K, Ca, and Cl, but the dominant source of 39Ar is from 39K. Radioactive 39Ar decays back to 39K by beta emission with a half-life of 269 years, but the decay is slow compared to the analysis time and can be ignored (Faure, 1986). The principal “advantage” of 40Ar/39Ar dating is that argon can be released partially by stepwise heating of irradiated samples, producing a spectrum of dates related to the “thermal history of the rock” (understanding that Argon is a gas while Potassium is not).
Because of this, it is much easier to determine a 40K/40Ar ratio and do it in a stepwise fashion with varying amounts of time and heat. This “stepwise” testing is thought to eliminate the errors caused by “extraneous” argon that might have “contaminated” the rock over time either by a loss or a gain of “outside” argon (ie: atmospheric argon). The problem with this theory is that who is to know which step, or average of steps in the process represents the “correct” 40K/40Ar ratio? How is this calibrated?
Recent experiments on volcanoes of known ages have been done using the 40Ar/39Ar dating method, which seem to confirm its accuracy. Recent testing of volcanic material from Mt. Vesuvius was dated accurately with the 40Ar/39Ar method to within seven years of the actual event.3 Of note however is that this test was not double blinded, and the number of such tests is not statistically significant as far as scientific analysis is concerned. A study is generally not considered to be very reliable unless it is a double-blinded study of an appropriately large sample size.
Specific Problems with K-Ar and Ar-Ar Dating[/siz]
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 “ages”. Since 40K/40Ar and 40Ar/39Ar dating are most commonly used to “prove” the ancient age of many life forms, I will discuss these dating methods specifically in more detail and show that they, along with the other common methods of isotope dating, are to be highly questioned. I will begin this section with a short discussion from Andrew Snelling, an associate professor of geology in El Cajon, California.
According to the assumptions foundational to potassium-argon (K-Ar) and argon-argon (Ar-Ar) dating of rocks, there should not be any daughter radiogenic argon (40Ar*) in rocks when they form. When measured, all 40Ar* in a rock is assumed to have been produced by in situ radioactive decay of 40K within the rock since it formed. However, it is well established that volcanic rocks (e.g. basalt) contain excess 40Ar*, that is, 40Ar which cannot be attributed to either atmospheric contamination or in situ radioactive decay of 40K. This excess 40Ar* represents primordial Ar carried from source areas in the earth's mantle by the parent magmas, is inherited by the resultant volcanic rocks, and thus has no age significance.
However, are all other rocks in the earth's crust also susceptible to "contamination" by excess 40Ar* emanating from the mantle? If so, then the K-Ar and Ar-Ar "dating" of crustal rocks would be similarly questionable.
When muscovite (a common mineral in crustal rocks) is heated to 740°-860°C under high Ar pressures for periods of 3 to 10.5 hours it absorbs significant quantities of Ar, producing K-Ar "ages" of up to 5 billion years, and the absorbed Ar is indistinguishable from radiogenic argon (40Ar*).2 In other experiments muscovite was synthesized from a colloidal gel under similar temperatures and Ar pressures, the resultant muscovite retaining up to 0.5 wt% Ar at 640°C and a vapor pressure of 4,000 atmospheres.3 This is approximately 2,500 times as much Ar as is found in natural muscovite. Thus under certain conditions Ar can be incorporated into minerals which are supposed to exclude Ar when they crystallize.
Because it is known that excess 40Ar* is carried from the mantle by plumes of mafic magmas up into the earth's crust, it is equally likely that much of the excess 40Ar* in crustal rocks could be primordial 40Ar. Thus, we have no way of knowing if any of the 40Ar* measured in crustal rocks has any age significance. Additional to the primordial 40Ar from the mantle is 40Ar* released from minerals and rocks during diagenesis and metamorphism, so that there is continual migration and circulation of both primordial 40Ar and 40Ar* in the crust which is reflected in their presence in CO2-rich natural gases. Therefore, when samples of crustal rocks are analyzed for K-Ar andAr-Ar "dating," one can never be sure that whatever 40Ar* is in the rocks is from in situ radioactive decay of 40K since their formation, or if some or all of it came from the mantle or from other crustal rocks and minerals. Thus all K-Ar and Ar-Ar "dates" of crustal rocks are questionable, as well as fossil "dates" calibrated by them.
In summary, evolutionists assume that since argon is a gas, all of it should have escaped from the lava before it cooled. Therefore, all the 40Ar in the rock should be the result of decay from potassium. Based on the measured potassium, argon, and the decay rate, they calculate an age. That is why it does not matter how long the magma was in the volcano before it erupted. They believe that when the volcano erupts, all the 40Ar escapes, and the atomic clock gets reset to zero.
If all the argon escaped from hot lava of volcanoes that erupted long ago, then all the argon should escape from the hot lava of volcanoes that erupt in modern times too. But modern lava does have 40Ar in it. This is known as the “excess argon problem” in geological circles. My position is that there is no such thing as excess argon. The rocks have the right amount of argon in them. This amount just happens to be more than the amount predicted by an incorrect theory.
Examples of Problems with Radiometric Dating Techniques[/siz]
Dalrymple's work early work on 26 historic lava flows showed that many of them had excess argon and were not set to zero at the eruption of the volcano. The following is the data from these tests:
Hualalai basalt, Hawaii (AD 1800-1801) 1.6±0.16 Ma; 1.41±0.08 Ma
Mt. Etna basalt, Sicily (122 BC) 0.25±0.08 Ma
Mt. Etna basalt, Sicily (AD 1972) 0.35±0.14 Ma
Mt. Lassen plagioclase, California (AD 1915) 0.11±0.03 Ma
Sunset Crater basalt, Arizona (AD 1064-1065) 0.27±0.09 Ma; 0.25±0.15 Ma
Far from being rare, there are numerous reported examples of excess 40Ar in recent or young volcanic rocks producing excessively old K-Ar "ages":
Mt. St. Helens lava dome (1986) 2.8± 0.6 MA
Akka Water Fall flow, Hawaii (Pleistocene) 32.3±7.2 Ma
Kilauea Iki basalt, Hawaii (AD 1959) 8.5±6.8 Ma
Mt. Stromboli, Italy, volcanic bomb (September 23, 1963) 2.4±2 Ma
Mt. Etna basalt, Sicily (May 1964) 0.7±0.01 Ma
Medicine Lake Highlands obsidian,
Glass Mountains, California (<500 years old) 12.6±4.5 Ma
Hualalai basalt, Hawaii (AD 1800-1801) 22.8±16.5 Ma
Rangitoto basalt, Auckland, NZ (<800 years old) 0.15±0.47 Ma
Alkali basalt plug, Benue, Nigeria (<30 Ma) 95 Ma
Olivine basalt, Nathan Hills, Victoria Land,
Antarctica (<0.3 Ma) 18.0±0.7 Ma
Anorthoclase in volcanic bomb, Mt Erebus,
Antarctica (1984) 0.64±0.03 Ma
Kilauea basalt, Hawaii (<200 years old) 21±8 Ma
Kilauea basalt, Hawaii (<1,000 years old) 42.9±4.2 Ma; 30.3±3.3 Ma
East Pacific Rise basalt (<1 Ma) 690±7 Ma
Seamount basalt, near East Pacific Rise (<2.5 Ma) 580±10 Ma; 700±150 Ma
East Pacific Rise basalt (<0.6 Ma) 24.2±1.0 Ma
Investigators also have found that excess 40Ar is trapped in the minerals within lava flows.7, 8, 9 Several instances have been reported of phenocrysts with K-Ar "ages" 1-7 millions years greater than that of the whole rock, and one K-Ar "date" on olivine phenocrysts in a recent (<13,000 year old) basalt was greater than 110 Ma.10 Laboratory experiments have tested the solubility of argon in synthetic basalt melts and their constituent minerals, with olivine retaining 0.34 ppm 40Ar.11, 12 It was concluded that the argon is held primarily in lattice vacancy defects within the minerals.
The obvious conclusion most investigators have reached is that the excess 40Ar had to be present in the molten lavas when extruded, which then did not completely degas as they cooled, the excess 40Ar becoming trapped in constituent minerals and the rock fabrics themselves. However, from whence comes the excess 40Ar, that is, 40Ar which cannot be attributed to atmospheric argon or in situ radioactive decay of 40K? It is not simply "magmatic" argon? Funkhouser and Naughton found that the excess 40Ar in the 1800-1801 Hualalai flow, Hawaii, resided in fluid and gaseous inclusions in olivine, plagioclase, and pyroxene in ultramafic xenoliths in the basalt, and was sufficient to yield "ages" of 2.6 Ma to 2960 Ma.13 Thus, since the ultramafic xenoliths and the basaltic magmas came from the mantle, the excess 40Ar* must initially reside there, to be transported to the earth's surface in the magmas.
Many recent studies confirm the mantle source of excess 40Ar. Hawaiian volcanism is typically cited as resulting from a mantle plume, most investigators now conceding that excess 40Ar in the lavas, including those from the active Loihi and Kilauea volcanoes, is indicative of the mantle source area from which the magmas came. Considerable excess 40Ar measured in ultramafic mantle xenoliths from Kerguelen Archipelago in the southern Indian Ocean likewise is regarded as the mantle source signature of hotspot volcanism.14 Indeed, data from single vesicles in mid-ocean ridge basalt samples dredged from the North Atlantic suggest the excess 40Ar in the upper mantle may be almost double previous estimates, that is, almost 150 times more than the atmospheric content (relative to 36Ar).15 Another study on the same samples indicates the upper mantle content of 40Ar could be even ten times higher.16
Further confirmation comes from diamonds, which form in the mantle and are carried by explosive volcanism into the upper crust and to the surface. When Zashu et al. obtained a K-Ar isochron "age" of 6.0±0.3 Ga for 10 Zaire diamonds, it was obvious excess 40Ar was responsible, because the diamonds could not be older than the earth itself.14 These same diamonds produced 40Ar/39Ar "age" spectra yielding a ~5.7 Ga isochron.17 It was concluded that the 40Ar is an excess component which has no age significance and is found in tiny inclusions of mantle-derived fluid.
The conventional K-Ar dating method was applied to the 1986 dacite flow from the new lava dome at Mount St. Helens, Washington. Porphyritic dacite which solidified on the surface of the lava dome in 1986 gives a whole rock K-Ar 'age ' of 0.35 ± 0.05 million years (Ma). Mineral concentrates from the dacite which formed in 1986 give K-Ar 'ages 'from 0.34 ± 0.06 Ma (feldspar-glass concentrate) to 2.8 ± 0.6 Ma (pyroxene concentrate). These 'ages 'are, of course, preposterous. The fundamental dating assumption ('no radiogenic argon was present when the rock formed ') is questioned by these data. Instead, data from this Mount St. Helens dacite argue that significant 'excess argon 'was present when the lava solidified in 1986. Phenocrysts of orthopyroxene, hornblende and plagioclase are interpreted to have occluded argon within their mineral structures deep in the magma chamber and to have retained this argon after emplacement and solidification of the dacite. The amount of argon occluded is probably a function of the argon pressure when mineral crystallization occurred at depth and/or the tightness of the mineral structure. Orthopyroxene retains the most argon, followed by hornblende, and finally, plagioclase. The lava dome at Mount St. Helens dates very much older than its true age because phenocryst minerals inherit argon from the magma. The study of this Mount St. Helens dacite causes the more fundamental question to be asked—how accurate are K-Ar 'ages 'from the many other phenocryst-containing lava flows world-wide?18
It is often said that a great many dating methods, used on a single specimen, will agree with each other, thus establishing the accuracy of the date given. In reality, 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 (a gas) 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 (Especially noting that Dalrymple suggested that only K-Ar dating methods were at all trust worthy). 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. I have seen no good double-blinded research studies that say otherwise. One would think that if this were a good science, then such studies would be done and published, but they are strangely lacking.
Potassium is about 2.5% of the earth's crust. About 1/10,000 of potassium is 40K, which decays into 40Ar with a half-life of 1.25 billion years. Actually, only about 1/10th of the40K decays to Argon, and the rest decays to calcium. Argon is about 3.6 x 10-4 % of the earth's crust. We can assume then that the magma is probably about 2.5% potassium and about 0.00025% of the radioactive form, Potassium-40 (40K). Now, Lets say we are trying to date a one billion year old rock. How much of it would be 40K? Starting with 0.00025% as the modern concentration of 40K in magma, we would have to divide by roughly two (About one half-life). This would leave us with a 0.000125% of 40K. Now, about 90% of the decay product is calcium and only about 10% is Ar-40. This gives about 0.0000125% 40Ar in the total make-up of the rock. This is about one ten millionth of the mass of the rock, a very tiny fraction. If the rock weighed one gram, the Ar-40 in the rock would weight one ten millionth of a gram. And yet, with a relatively large amount of argon in the air, argon filtering up from rocks below, excess argon in lava, the fact that argon and potassium are water soluble, and the fact that argon is mobile in rock and is a gas, we are still expecting this wisp of argon gas to tell us how old the rock is? The percentage of 40Ar is even less for younger rocks. For example, it would be about one part in 100 million for rocks in the vicinity of 50-60 million years old. However, to get just one part in 10 million of argon in a rock in a thousand years, we would only need to get one part in 10 billion entering the rock each year. This would be less than one part in a trillion entering the rock each day, on the average. This would suffice to give a rock an average computed potassium-argon age of over a billion years. Some geochronologists believe that a possible cause of excess argon is that argon diffuses into certain minerals progressively with time and pressure. Significant quantities of argon may be introduced into a mineral even at pressures as low as one bar.
We can also consider the average abundance of argon in the crust. If we assume that a rock has 1/400,000 40K, that is, 2.5 x 10-6 40K, and 3.6 x 10-6 40Ar, then eight times this much 40K must have decayed, thus about 28.8 x 10-6 parts of 40K have decayed, so there is less than 1/10 of the original 40K left. This implies a radiometric age of over 4 billion years. So a rock can get a very old radiometric age just by having average amounts of potassium and argon. It seems reasonable to me that the large radiometric ages are simply a consequence of mixing, and not related to ages at all, at least not necessarily the ages of the rocks themselves. The rates of exchange that would mess up “dates” are very small. It seems to me to be a certainty that water and gas will enter most, if not all, volcanic type rocks through tiny openings and invalidate almost all K-Ar ages. Even if magma was set to “zero time” at the eruption of a volcano, over the course of eons of time and exposure to atmospheric and other sources of extraneous argon, it would seem that contamination would be inevitable. This contamination would seem to be more and more of a problem the older the rock became.
Let me illustrate the circulation patterns of argon in the earth's crust. About 2.5 percent of the earth's crust is believed to be potassium, and about 1/10,000 of this is 40K, which decays to 40Ar with a half-life of about 1.25 billion years. 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 some minerals absorb argon (“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 various pressures, temperatures, moisture, nature of the materials and a variety of other factors all play together to challenge the validity of K-Ar and/or Ar-Ar dating.
Interesting Quotes[/siz]
Two important assumptions are implicit in this equation: First, that we are dealing with a closed system. And second, that no atoms of the daughter were present in the system when it formed. These assumptions furnish the most serious limitations on the accumulation clock. Rigorously closed systems probably do not exist in nature, but surprisingly, many minerals and rocks satisfy the requirement well enough to be useful for nuclear age determination. The problem is one of judicious geologic selection.", Henry Fall, "ASSUMPTIONS", AGES OF ROCKS, PLANETS & STARS, p.vi.
"Certain assumptions presupposes that the concentration of uranium in any specimen has remained constant over the specimen's life...groundwater percolation can leach away a proportion of the uranium present in the rock crystals. The mobility of the uranium is such that as one part of a rock formation is being improvised another part can become abnormally enriched. Such changes can also take place at relatively low temperatures." J.D. Macdougall, “SHIFTY URANIUM”, Scientific American, Vol.235(6):118
"What complicates things for the uranium-lead method is that nonradiogenic lead 204, 206, 207 and 208 also exist naturally, and scientists are not sure what the ratios of nonradiogenic to radiogenic lead were early in the moon's history...The problem of how much lead was around to begin with still remains...If all of the age-dating methods (rubidium-strontium, uranium-lead and potassium-argon) had yielded the same ages, the picture would be neat. But they haven't. The lead ages, for example, have been consistently older...Isotopic ages have been obtained for material from five landing sites on the moon--those of Apollo's 11, 12, 14, 15 and Luna 16; each site has a different age. But in a given site, the ages also vary...Ideally, however, any one basaltic rock from a given site should yield the same isotopic age, regardless of the method used.", Everly Driscoll, "DATING OF MOON SAMPLES: PITFALLS AND PARADOXES", Science News, Vol. 101, p. 12
"Studies of the helium method (2) have shown that low ages based on helium, obtained on common rockforming minerals, do not necessarily reflect diffusive loss of helium from the lattices of those minerals; under ideal conditions, some mineral lattices even appear to retain helium quantitatively for longer than 10 8years." Fanale & Schaeffer, Brookhaven National Laboratory, Science Vol.149, p.312
"There has been in recent years the horrible realization that radiodecay rates are not as constant as previously thought, nor are they immune to environmental influences. And this could mean that the atomic clocks are reset during some global disaster, and events which brought the Mesozoic to a close may not be 65 million years ago but, rather, within the age and memory of man." Frederic B. Jueneman, FAIC, Industrial Research & Development, p.21, Tune 1982
"It is now well known that KAr ages obtained from different minerals in a single rock may be strikingly discordant." Joan C. Engels, “DIFFERENT AGES FROM ONE ROCK”, Journal of Geology, ,Vol.79, p.609
"We suspect that the lack of concordance may result in some part, from the choice of isotope ratios from primitive lead, rather than from lead gain or Uranium loss. It therefore follows that the whole of the classical interpretation of the meteorite, lead isotope data is in doubt and that the radiometric estimates of the age of the earth are placed in jeopardy." Gail, Arden, & Huchenson Oxford, FOUNDATION DECAYS, Nature, Vol.240, p.67.
"The radiogenic argon and helium contents of three basalts erupted into the deep ocean from an active volcano (Kilauea) have been measured. Ages calculated from these measurements increase with sample depth up to 22 million years for lavas deduced to be recent....it is possible to deduce that these lavas are very young, probably less than 200 years old. The samples, in fact, may be very recent...", C.S. Nobel & J.J. Naughton, RECENT LAVA @ 22M, Dept. of Chem, Hawaiian Inst. of Geophysics, Science, Vol.162, p.265
"In conventional interpretation of KAr age data, it is common to discard ages which are substantially too high or too low compared with the rest of the group or with other available data such as the geological time scale. The discrepancies between the rejected and the accepted are arbitrarily attributed to excess or loss of argon." A. HAYATSU, “ARBITRARY”, Dept. of Geophysics, U. of Western Ontario, Canadian Journal Of Earth Science, 16:974.
"In general, dates in the 'correct ball park' are assumed to be correct and are published, but those in disagreement with other data are seldom published nor are the discrepancies fully explained." R. L. MAUGER, E. Carolina U., DISSENTERS EJECTED, Contributions To Geology, Vol.15 (1): 17
"If we assume that (1) a rock contained no Pb206 when it was formed, (2) all Pb206 now in the rock was produced by radioactive decay of u238, (3) the rate of decay has been constant, (4) there has been no differential leaching by water of either element, and (5) no U238 has been transported into the rock from another source, then we might expect our estimate of age to be fairly accurate. Each assumption is a potential variable, the magnitude of which can seldom be ascertained. In cases where the daughter product is a gas, as in the decay of potassium (K40) to the gas argon (Ar 40) it is essential that none of the gas escapes from the rock over long periods of time...It is obvious that radiometric technique may not be the absolute dating methods that they are claimed to be. Age estimates on a given geological stratum by different radiometric methods are often quite different (sometimes by hundreds of millions of years). There is no absolutely reliable long-term radiological clock. The uncertainties inherent in radiometric dating are disturbing to geologists and evolutionists...". W.D. Stansfield, Prof. Biological Science, Cal. Polyt. State U., THE SCIENCE OF EVOLUTION, 1977, p.84.
"The two principle problems have been the uncertainties in the radioactive decay constants of potassium and in the ability of minerals to retain the argon produced by this decay.” G.W. Wetherill, "Radioactivity of Potassium and Geologic Time," in Science, September 20, 1957, p. 545.
"The conventional K-Ar dating method was applied to the 1986 dacite flow from the new lava dome at Mount St. Helens, Washington. Porphyritic dacite, which solidified on the surface of the lava dome in 1986, gives a whole rock K-Ar 'age ' of 0.35 ± 0.05 million years (Ma). Mineral concentrates from the dacite, which formed in 1986, give K-Ar 'ages 'from 0.34 ± 0.06 Ma (feldspar-glass concentrate) to 2.8 ± 0.6 Ma (pyroxene concentrate). These 'ages 'are, of course, preposterous. The fundamental dating assumption ('no radiogenic argon was present when the rock formed ') is questioned by these data. Instead, data from this Mount St. Helens dacite argue that significant 'excess argon 'was present when the lava solidified in 1986." Steven A. Austin, Creation Ex Nihilo Technical Journal Vol. 10 (Part 3) - ISSN 1036 CEN Tech. J, 1996.
"Processes of rock alteration may render a volcanic rock useless for potassium-argon dating . . 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." J.F. Evernden, et. al., "K / A Dates and Cenozoic Mannalian Chronology of North America," in American Journal of Science, February 1964, p. 154.
"As much as 80 percent of the potassium in a small sample of an iron meteorite can be removed by distilled water in 4.5 hours." L.A. Rancitelli and D.E. Fisher, "Potassium-Argon Ages of Iron Meteorites," in Planetary Science Abstracts, 48th Annual Meeting of the American Geophysical Union (1967), p. 167.
"Why do the radioactive ages of lava beds laid down within a few weeks of each other differ by millions of years?" Glenn R. Morton, "Electromagnetism and the Appearance of Age," in Creation Research Society Quarterly, March 1982, p. 229.
"Situations for which we have both the carbon-14 and potassium-argon ages for the same event usually indicate that the potassium-argon ‘clock’ did not get set back to zero. Trees buried in an eruption of Mount Rangotito in Auckland Bay area of New Zealand provide a prime example. The carbon-14 age of the buried trees is only 225 years, but some of the overlying volcanic material has a 465,000-year potassium-argon age.” (Harold Coffin, Origin by Design, pp. 400.)
Lunar soil collected by Apollo 11 gave discordant ages by different methods” Pb207/Pb206, 4.67 billion ; Pb206 / U238, 5.41 billion; Pb207 / U238, 5.41 billion; Pb207 / U235, 4.89 billion; and Pb208 / Th232, 8.2 billion years. Rocks from the same location yielded K / Ar ages of around 2.3 billion years.” (R.E. Kofahl and K.L. Segraves, Creation Explanation (1975), pp. 200, 201.)
"Actually, the method (of comparing lead isotopes to make specimen dating more accurate) is subject to several errors. [1] Loss of radon 222 raises the lead: lead ratio and the calculated age. [2] A rather large error may be introduced by the uncertainty in the composition of the original lead. This error may exceed the measured value when dealing with younger uranium minerals containing even small amounts of original lead, as clearly recognized by Holmes when the method was first proposed. [3] Presence of old radiogenic lead (formed in a prior site of the parent uranium) may cause great error. [4] Instrumental errors in mass spectrometry may yield consistently high apparent proportions of lead 204 and lead 207. [5] Re-distribution of elements by renewed hydrothermal activity may be a serious source of error in all-lead methods. Henry Faul, Nuclear Geology (1954), p. 295.
"And what essentially is this actual time scale? On what criteria does it rest? When all is winnowed out and the grain reclaimed from the chaff it is certain that the grain in the product is mainly the paleontologic record [strata dating based on index fossil theories] and highly likely that the physical record [radioactive dating] is the chaff "~*E.M. Spieker, "Mountain-Building Chronology and the Nature of the Geologic Time-Scale," in Bulletin of the American Association of Petroleum Geologists, August 1956, p 1806.
"The two uranium-lead ages often differ from each other markedly, and the thorium-lead age on the same mineral is almost always drastically lower than either of the others. " L.T. Aldrich, "Measurement of Radioactive Ages of Rocks," in Science, May 18, 1956, p.872.
"Most of the ages obtained by the lead:thorium method disagree with the ages of the same minerals computed by other lead methods. The reasons for this disagreement are largely unknown. Henry Faul, Nuclear Geology (1954), p.295.
"The most reasonable age (from among the many conflicting "dates" offered) can be selected only alter careful consideration of independent geochronologic data as well as field, stratigraphic and paleontologic evidence, and the petrographic and paragenetic relations.” L.R. Stief, T.W. Stem and R.N. Eichler, "Algebraic and Graphic Methods for Evaluating Discordant Lead-Isotope Ages," in U.S. Geological Survey Professional Papers, No. 414-E (1963).
It is also of interest in regard to radiometric dating that Robert Gentry claims to have found "squashed" polonium haloes as well as embryonic uranium radiohaloes in coal deposits from many geological layers claimed to be hundreds of millions of years old. (See the Oct.15, 1976 issue of Science.) These haloes represent particles of polonium and uranium, which penetrated into the coal at some point and produced a halo by radioactive decay. The fact that they are squashed indicates that part of the decay process began before the material was compressed, so the polonium had to be present before compression. Since coal is relatively incompressible, Gentry concludes that these particles of uranium and polonium must have entered the deposit before it turned to coal. However, there is a very small amount of lead with the uranium; if the uranium had entered hundreds of millions of years ago, then there should be much more lead. The amount of lead present is consistent with an age of thousands rather than millions of years. It's hard to believe, according to conventional geological time scales, that this coal was compressed any time within the past several thousand or even hundred million years.
SOURCE: http://naturalselection.0catch.com/Files/Radiometric%20Dating.html
Gee, and I read all of that.
