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Problems with the U-Pb Radioisotope Dating Methods—1. Common Pb

READ MORE Properties, occurrence, and uses Potassium metal is soft and white with a silvery lustre, has a low melting point , and is a good conductor of heat and electricity. Potassium imparts a lavender colour to a flame, and its vapour is green. Potash mine at Esterhazy, Sask. The waste liquors from certain saltworks may contain up to 40 grams per litre of potassium chloride and are used as a source of potassium. K Most potassium is present in igneous rocks, shale, and sediment in minerals such as muscovite and orthoclase feldspar that are insoluble in water; this makes potassium difficult to obtain. Molten KCl is continuously fed into a packed distillation column while sodium vapour is passed up through the column. Efforts to devise a scheme for commercial electrolytic production of potassium have been unsuccessful because there are few salt additives that can reduce the melting point of potassium chloride to temperatures where electrolysis is efficient.

How Old is the Earth

There are 24 known isotopes of potassium, three of which occur naturally: Naturally occurring 40 K has a half-life of 1. It decays to stable 40 Ca by beta decay The conventional K-Ar dating method depends on the assumption that the rocks contained no argon at the time of formation and that all the subsequent radiogenic argon 40 Ar was quantitatively retained. Minerals are dated by measurement of the concentration of potassium and the amount of radiogenic 40 Ar that has accumulated.

Both Pb and Pb are short-lived intermediates in the U decay chain fig.

With time, it became apparent that this classification scheme was much too simple. A fourth category, known as spontaneous fission, also had to be added to describe the process by which certain radioactive nuclides decompose into fragments of different weight. Alpha decay is usually restricted to the heavier elements in the periodic table. Only a handful of nuclides with atomic numbers less than 83 emit an -particle.

The product of -decay is easy to predict if we assume that both mass and charge are conserved in nuclear reactions. Alpha decay of the U"parent" nuclide, for example, produces Th as the"daughter" nuclide. There are three different modes of beta decay:

Potassium Element Facts

At the time that Darwin"s On the Origin of Species was published, the earth was"scientifically" determined to be million years old. By , it was found to be 1. In , science firmly established that the earth was 3. Finally in , it was discovered that the earth is"really" 4. In these early studies the order of sedimentary rocks and structures were used to date geologic time periods and events in a relative way.

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These are K-Ar data obtained on glauconite, a potassium-bearing clay mineral that forms in some marine sediment. Woodmorappe fails to mention, however, that these data were obtained as part of a controlled experiment to test, on samples of known age, the applicability of the K-Ar method to glauconite and to illite, another clay mineral. He also neglects to mention that most of the 89 K-Ar ages reported in their study agree very well with the expected ages.

Evernden and others 43 found that these clay minerals are extremely susceptible to argon loss when heated even slightly, such as occurs when sedimentary rocks are deeply buried. As a result, glauconite is used for dating only with extreme caution. The ages from the Coast Range batholith in Alaska Table 2 are referenced by Woodmorappe to a report by Lanphere and others Whereas Lanphere and his colleagues referred to these two K-Ar ages of and million years, the ages are actually from another report and were obtained from samples collected at two localities in Canada, not Alaska.

1. Rate of Decay

Wujing Zongyao , Four Great Inventions , List of Chinese inventions , and Heilongjiang hand cannon Based on a 9th-century Taoist text, the invention of gunpowder by Chinese alchemists was likely an accidental byproduct from experiments seeking to create elixir of life. In the following centuries various gunpowder weapons such as bombs , fire lances , and the gun appeared in China. A slow match for flame throwing mechanisms using the siphon principle and for fireworks and rockets is mentioned.

However by the Song court was producing hundreds of thousands of fire arrows for their garrisons.

Why methods in general are inaccurate I admit this is a very beautiful theory.

Leibnitz reworked Descartes"s cosmogony. Protogea was published much later in An essay toward a Natural History of the Earth. Woodward came down fairly strongly for the view that the flood was an act of God that could not be accounted for by normal physical processes. He also postulated hydrological sorting to account for the ordering of fossils. Whiston added comets to Burnet"s cosmogony as the source of the waters of the flood.

Lectures and Discourse of Earthquakes and Subterranean Eruptions. Hooke believed that the fossils were the remains of extinct species and could not be accounted for by the Flood. Using Descartes"s cosmology, the assumption that the earth was once entirely flooded, and the observation that the sea level was dropping three inches per century near his home, he calculated the age of the earth to be greater than 2 billion years.

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Outlook Other Abstract U-Pb radioisotope dating is now the absolute dating method of first choice among geochronologists, especially using the mineral zircon. A variety of analytical instruments have also now been developed using different micro-sampling techniques coupled with mass spectrometers, thus enabling wide usage of U-Pb radioisotope dating.

However, problems remain in the interpretation of the measured Pb isotopic ratios to transform them into ages. Among them is the presence of non-radiogenic Pb of unknown composition, often referred to as common or initial Pb. There is also primordial Pb that the earth acquired when it formed, its isotopic composition determined as that of troilite in the Canyon Diablo iron meteorite. Subsequently new crustal rocks formed via partial melts from the mantle.

After he discovered that France was not self-sufficient in gunpowder, a Gunpowder Administration was established; to head it, the lawyer Antoine Lavoisier was appointed.

How accurate are carbon-dating methods? All methods of radioactive dating rely on three assumptions that may not necessarily be true: Rate of Decay It is assumed that the rate of decay has remained constant over time. This assumption is backed by numerous scientific studies and is relatively sound. However, conditions may have been different in the past and could have influenced the rate of decay or formation of radioactive elements.

Evolutionists assume that the rate of cosmic bombardment of the atmosphere has always remained constant and that the rate of decay has remained constant. Thus radioactive dating relies purely on assumptions. We could put forward the following counter arguments to the constancy of these assumptions: The current high rate of entry might be a consequence of a disturbed post-Flood environment that altered the carbon to carbon ratio.

Pre-Flood dates would thus have to be discarded. Some scientists argue that the magnetic field of the earth has declined over time. Carbon comes from nitrogen and is independent of the carbon reservoir.

Changing Views of the History of the Earth

Radiometric dating In , shortly after the discovery of radioactivity , the American chemist Bertram Boltwood suggested that lead is one of the disintegration products of uranium, in which case the older a uranium-bearing mineral the greater should be its proportional part of lead. Analyzing specimens whose relative geologic ages were known, Boltwood found that the ratio of lead to uranium did indeed increase with age. After estimating the rate of this radioactive change, he calculated that the absolute ages of his specimens ranged from million to 2.

Though his figures were too high by about 20 percent, their order of magnitude was enough to dispose of the short scale of geologic time proposed by Lord Kelvin.

Theory of the Earth; or, an investigation of the laws observable in the composition, dissolution and restoration of land upon the globe.

Updated 8 January c Introduction In a related article on geologic ages Ages , we presented a chart with the various geologic eras and their ages. In a separate article Radiometric dating , we sketched in some technical detail how these dates are calculated using radiometric dating techniques. As we pointed out in these two articles, radiometric dates are based on known rates of radioactivity, a phenomenon that is rooted in fundamental laws of physics and follows simple mathematical formulas.

Dating schemes based on rates of radioactivity have been refined and scrutinized for several decades. The latest high-tech equipment permits reliable results to be obtained even with microscopic samples. Radiometric dating is self-checking, because the data after certain preliminary calculations are made are fitted to a straight line an"isochron" by means of standard linear regression methods of statistics.

The slope of the line determines the date, and the closeness of fit is a measure of the statistical reliability of the resulting date. Technical details on how these dates are calculated are given in Radiometric dating. Here is one example of an isochron, based on measurements of basaltic meteorites in this case the resulting date is 4.

Reliability of radiometric dating So, are radiometric methods foolproof? Just how reliable are these dates? As with any experimental procedure in any field of science, these measurements are subject to certain"glitches" and"anomalies," as noted in the literature. Skeptics of old-earth geology make great hay of these examples.

How accurate are Carbon-14 and other radioactive dating methods?

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A higher ratio means an older age.

The half-life of a radioisotope can be used to measure the age of things. The method is called radiodating. Radiodating can be used to measure the age of rocks see below and carbon dating can be used to date archaeological specimens. Using Uranium to Date Rock. Some rocks contain uranium which is radioactive and follows a decay series until it produces a stable isotope of lead. The amount of uranium in the rock is compared to the amount of lead and then the age of the rock can be calculated.

For example, it is found that there are equal amounts of uranium and lead in a rock. The proportion of uranium to lead would be 1 to 1 equal amounts. You can only use the ratio of uranium to lead to date rock if you are sure that there was no lead originally present in the rock and that all the lead in the rock has come from the decay of uranium. Using Potassium to Date Rock. Some rocks contain the radioisotope potassium which decays to form argon Argon is a stable isotope.

If the argon gas is unable to escape from the rock, then the proportions of potassium to argon can be used to date the rock.

The Radiometric Dating Game Radiometric dating methods estimate the age of rocks using calculations based on the decay rates of radioactive elements such as uranium, strontium, and potassium. On the surface, radiometric dating methods appear to give powerful support to the statement that life has existed on the earth for hundreds of millions, even billions, of years.

We are told that these methods are accurate to a few percent, and that there are many different methods.

All six naturally occurring U isotopes are unstable and decay.

See this page in: Hungarian , Russian , Spanish People who ask about carbon 14C dating usually want to know about the radiometric [1] dating methods that are claimed to give millions and billions of years—carbon dating can only give thousands of years. People wonder how millions of years could be squeezed into the biblical account of history.

Clearly, such huge time periods cannot be fitted into the Bible without compromising what the Bible says about the goodness of God and the origin of sin, death and suffering —the reason Jesus came into the world See Six Days? Christians , by definition, take the statements of Jesus Christ seriously. This only makes sense with a time-line beginning with the creation week thousands of years ago. It makes no sense at all if man appeared at the end of billions of years.

We will deal with carbon dating first and then with the other dating methods.

Potassium-argon (K-Ar) dating


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