# Potassium argon dating is useful for determining the age of the earth

9-4-2016 · The potassium - argon (K-Ar) isotopic dating method is especially useful for determining the age of lavas. Developed in the 1950s, it was important in ...

24-6-2008 · One of the most widely used dating methods is the potassium - argon method, which has been applied to ‘ dating ’ rocks for decades, especially igneous ...

Potassium is a chemical element with symbol K (derived from Neo-Latin, kalium) and atomic number 19. It was first isolated from potash, the ashes of plants, from ...

Radiometric dating or radioactive dating is a technique used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively ...

potassium permanganate n. A dark purple crystalline compound, KMnO4, used as an oxidizing agent and disinfectant and in deodorizers and dyes. potassium …

Argon . Argon was suspected to be present in air by Henry Cavendish in 1785 but wasn't discovered until 1894 by Lord Rayleigh and Sir William Ramsay.

20-2-2015 · Argon is an inert, colorless and odorless element — one of the Noble gases. Used in fluorescent lights and in welding, this element gets its name from ...

Although the time at which any * individual atom * will decay cannot be forecast, the time in which any given percentage of a sample will decay can be calculated to varying degrees of accuracy. The time that it takes for half of a sample to decay is known as the half life of the isotope. Some isotopes have half lives longer than the present age of the universe , but they are still subject to the same laws of quantum physics and will eventually decay, even if doing so at a time when all remaining atoms in the universe are separated by astronomical distances.

Various elements are used for dating different time periods; ones with relatively short half-lives like carbon -14 (or 14 C) are useful for dating once-living objects (since they include atmospheric carbon from when they were alive) from about ten to fifty thousand years old. See Carbon dating . Longer-lived isotopes provide dating information for much older times. The key is to measure an isotope that has had time to decay a measurable amount, but not so much as to only leave a trace remaining. Given isotopes are useful for dating over a range from a fraction of their half life to about four or five times their half life.

Symbolically, the process of radioactive decay can be expressed by the following differential equation, where * N* is the quantity of decaying nuclei and * k* is a positive number called the exponential decay constant . The meaning of this equation is that the rate of change of the number of nuclei over time is proportional only to the number of nuclei. This is consistent with the assumption that each decay event is independent and its chance does not vary over time.

where is the half-life of the element, is the time expired since the sample contained the initial number atoms of the nuclide, and is the remaining amount of the nuclide. We can measure directly, for example by using a radiation detector, and obtain a good estimate of by analyzing the chemical composition of the sample. The half-life , specific to each nuclide, can be accurately measured on a pure sample, and is known to be independent of the chemical composition of the sample, temperature and pressure. [1] Solving for gives us the estimated age of the sample:

You find a bone fragment and through analysis you determine that it contains 13% of its original carbon-14. The half-life of carbon-14 is approximately 5,730 years. Approximately how old is the bone?

Thus the bone is approximately 17,000 years old. (Our input data had two significant figures, so reporting a more accurate result would be meaningless.)

A important limitation of radiometric dating often overlooked by layman (and not always made clear in scholarly works as well) is that any date is actually a range, following the 68–95–99.7 rule .

Twenty-seven Brahma amphibolite samples were collected from various Inner Gorge outcrops as part of the RATE (Radioisotopes and the Age of The Earth) project. These included seven samples from a 150 meter long and 2 meter wide amphibolite body outcropping just upstream from the mouth of Clear Creek at river mile 84 (measured from Lees Ferry). All 27 samples were sent to two well-credentialed internationally-recognized, commercial laboratories for radioisotope analyses—potassium-argon (K-Ar) at a Canadian laboratory, and rubidium-strontium (Rb-Sr), samarium-neodymium (Sm-Nd), and lead-lead (Pb-Pb), at an Australian laboratory. Both laboratories use standard, best-practice procedures on state-of-the-art equipment.

These discordant results could easily be dismissed as an isolated aberration, perhaps due to the uncertain effects of metamorphism and any subsequent alteration, especially during erosion and weathering. However, they are confirmation of the repeated failure of all the radioisotope "dating" methods to successfully date Grand Canyon rocks. 7,8 Furthermore, papers in the general geological literature are also reporting discordant radioisotope "dates" when all the methods are applied to the same rock unit, 9 but tenuous "explanations" are given to account for the anomalous amounts of daughter products, and avoid the inescapable conclusion that the radioisotope methods simply do not yield reliable absolute ages.

The radioisotope methods, long touted as irrefutably dating the earth's rocks as countless millions of years old, have repeatedly failed to provide reliable and meaningful absolute ages for Grand Canyon rock layers. Irreconcilable disagreement within and between the methods is the norm, even at the outcrop scale. This is a devastating "blow" to the long ages that are foundational to uniformitarian geology and evolutionary biology. Yet the discordance patterns are consistent with past accelerated radioisotope decay, which would also render these "clocks" useless. Thus there is no reliable evidence to dispute that these metamorphosed basalt lava flows deep in Grand Canyon date back to the Creation Week only thousands of years ago.

Cite this article: Snelling, A. 2004. Radioisotope Dating of Grand Canyon Rocks: Another Devastating Failure for Long-Age Geology. Acts & Facts . 33 (10).

# Potassium - Wikipedia

Although the time at which any * individual atom * will decay cannot be forecast, the time in which any given percentage of a sample will decay can be calculated to varying degrees of accuracy. The time that it takes for half of a sample to decay is known as the half life of the isotope. Some isotopes have half lives longer than the present age of the universe , but they are still subject to the same laws of quantum physics and will eventually decay, even if doing so at a time when all remaining atoms in the universe are separated by astronomical distances.

Various elements are used for dating different time periods; ones with relatively short half-lives like carbon -14 (or 14 C) are useful for dating once-living objects (since they include atmospheric carbon from when they were alive) from about ten to fifty thousand years old. See Carbon dating . Longer-lived isotopes provide dating information for much older times. The key is to measure an isotope that has had time to decay a measurable amount, but not so much as to only leave a trace remaining. Given isotopes are useful for dating over a range from a fraction of their half life to about four or five times their half life.

Symbolically, the process of radioactive decay can be expressed by the following differential equation, where * N* is the quantity of decaying nuclei and * k* is a positive number called the exponential decay constant . The meaning of this equation is that the rate of change of the number of nuclei over time is proportional only to the number of nuclei. This is consistent with the assumption that each decay event is independent and its chance does not vary over time.

where is the half-life of the element, is the time expired since the sample contained the initial number atoms of the nuclide, and is the remaining amount of the nuclide. We can measure directly, for example by using a radiation detector, and obtain a good estimate of by analyzing the chemical composition of the sample. The half-life , specific to each nuclide, can be accurately measured on a pure sample, and is known to be independent of the chemical composition of the sample, temperature and pressure. [1] Solving for gives us the estimated age of the sample:

You find a bone fragment and through analysis you determine that it contains 13% of its original carbon-14. The half-life of carbon-14 is approximately 5,730 years. Approximately how old is the bone?

Thus the bone is approximately 17,000 years old. (Our input data had two significant figures, so reporting a more accurate result would be meaningless.)

A important limitation of radiometric dating often overlooked by layman (and not always made clear in scholarly works as well) is that any date is actually a range, following the 68–95–99.7 rule .