Why is u 238 used for dating rocks
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.
Levels of carbon-14 become difficult to measure and compare after about 50,000 years (between 8 and 9 half lives; where 1% of the original carbon-14 would remain undecayed).
The question should be whether or not carbon-14 can be used to date any artifacts at all? There are a few categories of artifacts that can be dated using carbon-14; however, they cannot be more 50,000 years old.
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.g. Prior to radiometric dating, evolution scientists used index fossils a.k.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.
As stated previously, carbon dating cannot be used on artifacts over about 50,000 years old.
These artifacts have gone through many carbon-14 half-lives, and the amount of carbon-14 remaining in them is miniscule and very difficult to detect.
Also, many fossils are contaminated with carbon from the environment during collection or preservation procedures.
If it sounds like circular reasoning, it is because this process in reality is based upon circular reasoning.
If we reverse the process to find the age of an alleged rock, the geologist takes his rock to the paleontologist, and the paleontologist goes to the same exact chart and looks for the “index fossil(s)” that normally are found in those rock layers. Henry Morris as follows: “Index fossils” are types of fossil (such as ammonites and coelacanths) that 19th century European evolutionists of the Victorian era claimed lived and died out many millions of years ago.
Once our geologist had the “index fossil” that was found approximately in the same layer as the newly discovered fossil, he would then see where in the geologic column it came from and presto, he now had a date for his newly discovered fossil.
He would simply go to a chart that listed the geologic column by ‘ages’ and find the place where the index fossil appears, and thereby the geologists could tell the paleontologist how old his fossil was.
the geological column and approximate ages of all the fossil-bearing strata were all worked out long before anyone ever heard or thought about radioactive dating …