Radiocarbon Dating - Kids History
There are two basic approaches: relative geologic age dating, and absolute geologic age No bones about it, fossils are important age markers. But the most accurate forms of absolute age dating are radiometric methods. Radiocarbon Dating. One method that scientists use to date ancient fossils and artifacts is called radiocarbon dating. All living things on Earth are made up of a. Fossils may be dated by taking samples of rocks from above and below the Radiometric dating methods are used to establish the geological time scale.
The short half-life of carbon means it cannot be used to date fossils that are allegedly extremely old, e. The question should be whether or not carbon can be used to date any artifacts at all? The answer is not simple.
There are a few categories of artifacts that can be dated using carbon; however, they cannot be more than 50, years old. Carbon cannot be used to date biological artifacts of organisms that did not get their carbon dioxide from the air. This rules out carbon dating for most aquatic organisms, because they often obtain at least some of their carbon from dissolved carbonate rock.
The age of the carbon in the rock is different from that of the carbon in the air and makes carbon dating data for those organisms inaccurate under the assumptions normally used for carbon dating. This restriction extends to animals that consume seafood in their diet.
How Do Scientists Date Ancient Things?
As stated previously, carbon dating cannot be used on artifacts over about 50, years old. These artifacts have gone through many carbon half-lives, and the amount of carbon remaining in them is miniscule and very difficult to detect.
Carbon dating cannot be used on most fossils, not only because they are almost always allegedly too old, but also because they rarely contain the original carbon of the organism that has been fossilized.
Also, many fossils are contaminated with carbon from the environment during collection or preservation procedures. Scientists attempt to check the accuracy of carbon dating by comparing carbon dating data to data from other dating methods. Other methods scientists use include counting rock layers and tree rings. When scientists first began to compare carbon dating data to data from tree rings, they found carbon dating provided "too-young" estimates of artifact age. Scientists now realize that production of carbon has not been constant over the years, but has changed as the radiation from the sun has fluctuated.
Nuclear tests, nuclear reactors and the use of nuclear weapons have also changed the composition of radioisotopes in the air over the last few decades. This human nuclear activity will make precise dating of fossils from our lifetime very difficult due to contamination of the normal radioisotope composition of the earth with addition artificially produced radioactive atoms. The various confounding factors that can adversely affect the accuracy of carbon dating methods are evident in many of the other radioisotope dating methods.
Although the half-life of some of them are more consistent with the evolutionary worldview of millions to billions of years, the assumptions used in radiometric dating put the results of all radiometric dating methods in doubt.
- Radiometric dating facts for kids
- What is Carbon Dating?
- Geologic Age Dating Explained
The following is an article on this subject. These isotopes have longer half-lives and so are found in greater abundance in older fossils. Some of these other isotopes include: The assumptions are similar to the assumptions used in carbon dating.
Radiometric dating Facts for Kids
The mathematical premise undergirding the use of these elements in radiometric dating contains the similar confounding factors that we find in carbon dating method.
Most scientists today believe that life has existed on the earth for billions of years. This belief in long ages for the earth and the evolution of all life is based entirely on the hypothetical and non-empirical Theory of Evolution.
All dating methods that support this theory are embraced, while any evidence to the contrary, e.
Prior to radiometric dating, evolution scientists used index fossils a. A paleontologist would take the discovered fossil to a geologist who would ask the paleontologist what other fossils searching for an index fossil were found near their discovery.
If it sounds like circular reasoning, it is because this process in reality is based upon circular reasoning. Henry Morris as follows: These long time periods are computed by measuring the ratio of daughter to parent substance in a rock, and inferring an age based on this ratio.
This age is computed under the assumption that the parent substance say, uranium gradually decays to the daughter substance say, leadso the higher the ratio of lead to uranium, the older the rock must be.
Carbon, Radiometric Dating and Index Fossils - Creation Studies Institute
While there are many problems with such dating methods, such as parent or daughter substances entering or leaving the rock, e.
Geologists assert that generally speaking, older dates are found deeper down in the geologic column, which they take as evidence that radiometric dating is giving true ages, since it is apparent that rocks that are deeper must be older. But even if it is true that older radiometric dates are found lower down in the geologic column which is open to questionthis can potentially be explained by processes occurring in magma chambers which cause the lava erupting earlier to appear older than the lava erupting later.
Lava erupting earlier would come from the top of the magma chamber, and lava erupting later would come from lower down. A number of processes could cause the parent substance to be depleted at the top of the magma chamber, or the daughter product to be enriched, both of which would cause the lava erupting earlier to appear very old according to radiometric dating, and lava erupting later to appear younger. Plotting an isochron straight-line graph is used to solve the age equation graphically. It shows the age of the sample, and the original composition.
Preconditions The method works best if neither the parent nuclide nor the daughter product enters or leaves the material after its formation. Anything which changes the relative amounts of the two isotopes original and daughter must be noted, and avoided if possible. Contamination from outside, or the loss of isotopes at any time from the rock's original formation, would change the result.
It is therefore essential to have as much information as possible about the material being dated and to check for possible signs of alteration.
Measurements should be taken on samples from different parts of the rock body.
This helps to counter the effects of heating and squeezing, which a rock may experience in its long history. Different dating methods may be needed to confirm the age of a sample.
For example, a study of the Amitsoq gneisses from western Greenland used five different radiometric dating methods to examine twelve samples and got agreement to within 30 million years on an age of 3,my. Related pages Images for kids Thermal ionization mass spectrometer used in radiometric dating.
A concordia diagram as used in uranium-lead datingwith data from the Pfunze Belt, Zimbabwe.