How Old is the Earth

Exploring the wonders of geology in response to young-Earth claims Please read my guidelines and background posts before proceeding! Radiometric dating is not a simple topic. Chances are, you learned a simplified version of the technique at one point—if you remember your chemistry teacher discussing isotopes, half-lives, hourglasses, well, that was it—but have since removed the lesson to a box labeled “High School Amnesia” in some dark corner of your brain. If you’re reading this now, however, you might be curious to reopen that box in an effort to follow my argument as I answer the title of this post or, if nothing else, to avoid admitting that chemistry was “not really your thing”. But whatever your passion for decaying metals and your level of chemical comprehension is now, I want to share my confidence that you can follow along just fine. Anyone can learn technical jargon queue Wikipedia page for Potassium Argon Dating ; reading this post only requires a knack for scientific reasoning. Before I begin, there is one set of terms you should be able to distinguish:

The Radiometric Dating Game

This is very possible, and even likely. It is only an assumption that integral or adjacent lead could only be an end-product. In addition, there is “common lead, “which has no radioactive parent lead

potassium-argon dating in British noun a technique for determining the age of minerals based on the occurrence in natural potassium of a small fixed amount of radioisotope 40 K that decays to the stable argon isotope 40 Ar with a half-life of × 10 9 years.

In combination with other minerals in the body, potassium forms alkaline salts that are important in body processes and play an essential role in maintenance of the acid-base and water balance in the body. All body cells, especially muscle tissue, require a high content of potassium. A proper balance between sodium , calcium , and potassium in the blood plasma is necessary for proper cardiac function. Since most foods contain a good supply of potassium, potassium deficiency hypokalemia is unlikely to be caused by an unbalanced diet.

Possible causes include cushing’s syndrome due to an adrenal gland disorder and fanconi’s syndrome the result of a congenital kidney defect. The cause could also be an excessive dose of cortisone , prolonged vomiting or diarrhea, or thiazide diuretics, which are administered for treatment of hypertension. Signs of potassium deficiency can include weakness and lethargy, rapid pulse, nausea, diarrhea, and tingling sensations. If the body absorbs enough potassium but the element is not distributed properly, various disorders may develop.

Thus an abnormally low content of potassium in the blood may result in an intermittent temporary paralysis of the muscles, known as familial periodic paralysis. Potassium deficiency can be treated by administration of potassium supplements.

Absolute dating

This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. July Thermoluminescence[ edit ] Thermoluminescence testing also dates items to the last time they were heated. This technique is based on the principle that all objects absorb radiation from the environment.

Potassium-argon dating, method of determining the time of origin of rocks by measuring the ratio of radioactive argon to radioactive potassium in the rock. This dating method is based upon the decay of radioactive potassium to radioactive argon in minerals and rocks; potassium .

We can calculate the half-lives of all of these elements. All the intermediate isotopes between U and Pb are highly unstable, with short half-lives. That means they don’t stay around very long, so we can take it as given that these isotopes don’t appear on Earth today except as the result of uranium decay. We can find out the normal distribution of lead isotopes by looking at a lead ore that doesn’t contain any uranium, but that formed under the same conditions and from the same source as our uranium-bearing sample.

Then any excess of Pb must be the result of the decay of U When we know how much excess Pb there is, and we know the current quantity of U , we can calculate how long the U in our sample has been decaying, and therefore how long ago the rock formed. Th and U also give rise to radioactive series — different series from that of U , containing different isotopes and ending in different isotopes of lead. Chemists can apply similar techniques to all three, resulting in three different dates for the same rock sample.

Uranium and thorium have similar chemical behavior, so all three of these isotopes frequently occur in the same ores. If all three dates agree within the margin of error, the date can be accepted as confirmed beyond a reasonable doubt. Since all three of these isotopes have substantially different half-lives, for all three to agree indicates the technique being used is sound.

But even so, radioactive-series dating could be open to question.

Potassium-argon dating

Important We believe any unbiased reader will realize that we were fair with our treatment of the two models in the table above. Yet, although the theory of evolution matches the facts in some cases, evolution is still an unproven theory. By now, you may believe it should be your first choice also. Unlike many others that preceded us, we attempted to find a clear defense of evolution for two reasons: To keep from being accused of bias.

To keep from making claims that someone could refute later.

Potassium-argon definition is – being or relating to a method of dating paleontological or geological materials based on the radioactive decay of potassium to argon that has taken place in a specimen.

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. How the carbon clock works Carbon has unique properties that are essential for life on Earth. One rare form has atoms that are 14 times as heavy as hydrogen atoms: Carbon is made when cosmic rays knock neutrons out of atomic nuclei in the upper atmosphere.

These displaced neutrons, now moving fast, hit ordinary nitrogen 14N at lower altitudes, converting it into 14C. Unlike common carbon 12C , 14C is unstable and slowly decays, changing it back to nitrogen and releasing energy.

Absolute dating

He pioneered the use of radioactive isotopes to date relatively young rocks, thereby providing the first solid timeline for human evolution. Curtis collaborated with late UC Berkeley Professors John Reynolds, a physicist, and Jack Evernden, a seismologist, to take advantage of the radioactive decay of potassium into argon in volcanic rock to determine how long ago the rock formed. Using this potassium-argon method, he and his colleagues established precise dates for recent geologic time periods that allowed him to assign dates to fossilized human remains and prove they were much older than once thought.

Since the late 19th century, radioactive isotopes such as uranium and potassium have been used to date billion-year-old rocks, but dating young rocks was a challenge because the radioactive decay products in such rocks are present in minuscule quantities. Using then-new ultra high vacuum systems combined with mass spectrometry, UC Berkeley researchers were finally able to count these atoms and provide precise dates on young rocks.

*potassium–argon dating* A dating technique [1] for certain rocks that depends on the decay of the radioisotope potassium–40 to argon–40, a process with a half-life of about × years.

The International History Project Date: Archaeology studies past human behavior through the examination of material remains of previous human societies. These remains include the fossils preserved bones of humans, food remains, the ruins of buildings, and human artifacts—items such as tools, pottery, and jewelry. From their studies, archaeologists attempt to reconstruct past ways of life. Archaeology is an important field of anthropology, which is the broad study of human culture and biology.

Archaeologists concentrate their studies on past societies and changes in those societies over extremely long periods of time. However, archaeology is distinct from paleontology and studies only past human life. Archaeology also examines many of the same topics explored by historians. But unlike history—the study of written records such as government archives, personal correspondence, and business documents—most of the information gathered in archaeology comes from the study of objects lying on or under the ground Archaeologists refer to the vast store of information about the human past as the archaeological record.

The archeological record encompasses every area of the world that has ever been occupied by humans, as well as all of the material remains contained in those areas. Archaeologists study the archaeological record through field surveys and excavations and through the laboratory study of collected materials.

Potassium Element Facts

Dating methods Dating techniques are procedures used by scientists to determine the age of a specimen. Relative dating methods tell only if one sample is older or younger than another sample; absolute dating methods provide a date in years. The latter have generally been available only since

Potassium–argon dating, abbreviated K–Ar dating, is a radiometric dating method used in geochronology and archaeology. It is based on measurement of the product of the radioactive decay of an isotope of potassium (K) into argon (Ar).

Most half-lives taken from Holden, N. Isotopes with shorter half-lives cannot date very ancient events because all of the atoms of the parent isotope would have already decayed away, like an hourglass left sitting with all the sand at the bottom. Isotopes with relatively short half-lives are useful for dating correspondingly shorter intervals, and can usually do so with greater accuracy, just as you would use a stopwatch rather than a grandfather clock to time a meter dash.

On the other hand, you would use a calendar, not a clock, to record time intervals of several weeks or more. The half-lives have all been measured directly either by using a radiation detector to count the number of atoms decaying in a given amount of time from a known amount of the parent material, or by measuring the ratio of daughter to parent atoms in a sample that originally consisted completely of parent atoms. Work on radiometric dating first started shortly after the turn of the 20th century, but progress was relatively slow before the late page 4 forties.

However, by now we have had over fifty years to measure and re-measure the half-lives for many of the dating techniques. Very precise counting of the decay events or the daughter atoms can be done, so while the number of, say, rhenium atoms decaying in 50 years is a very small fraction of the total, the resulting osmium atoms can be very precisely counted. For example, recall that only one gram of material contains over 1 with 21 zeros behind atoms.

Even if only one trillionth of the atoms decay in one year, this is still millions of decays, each of which can be counted by a radiation detector! The uncertainties on the half-lives given in the table are all very small. There is no evidence of any of the half-lives changing over time. In fact, as discussed below, they have been observed to not change at all over hundreds of thousands of years. Igneous rocks are good candidates for dating.

Radiometric Dating: Methods, Uses & the Significance of Half-Life

Dinosaurs disappeared about 65 million years ago. That corn cob found in an ancient Native American fire pit is 1, years old. How do scientists actually know these ages? Geologic age dating—assigning an age to materials—is an entire discipline of its own.

potassium-argon dating noun a technique for determining the age of minerals based on the occurrence in natural potassium of a small fixed amount of radioisotope 40 K that decays to the stable argon isotope 40 Ar with a half-life of × 10 9 years.

Space-filling model of argon fluorohydride Argon’s complete octet of electrons indicates full s and p subshells. This full valence shell makes argon very stable and extremely resistant to bonding with other elements. Before , argon and the other noble gases were considered to be chemically inert and unable to form compounds; however, compounds of the heavier noble gases have since been synthesized.

The first argon compound with tungsten pentacarbonyl, W CO 5Ar, was isolated in However it was not widely recognised at that time. This discovery caused the recognition that argon could form weakly bound compounds, even though it was not the first. It forms at pressures between 4.

What Is Argon Dating?