Limitations of radiometric dating dating haram islam yahoo answers
Sometimes, however, numerous discordant dates from the same rock will plot along a line representing a chord on the Concordia diagram. is then interpreted to be the date that the system became closed, and the younger date, t*, the age of an event (such as metamorphism) that was responsible for Pb leakage.
Pb leakage is the most likely cause of discordant dates, since Pb will be occupying a site in the crystal that has suffered radiation damage as a result of U decay.
Such trapped Ar is not problematical when the age of the rock is in hundreds of millions of years.
The dating equation used for K-Ar is: Carbon Dating Radiocarbon dating is different than the other methods of dating because it cannot be used to directly date rocks, but can only be used to date organic material produced by once living organisms.
The initial ratio has particular importance for studying the chemical evolution of the Earth's mantle and crust, as we discussed in the section on igneous rocks. If this happens, then the date obtained will be older than the date at which the magma erupted.
For example lavas dated by K-Ar that are historic in age, usually show 1 to 2 my old ages due to trapped Ar.
But, again, exptrapolation of the discordia back to the two points where it intersects the Concordia, would give two ages - t* representing the possible metamorphic event and t and solve for t . This argument tells when the elements were formed that make up the Earth, but does not really give us the age of the Earth. Thus, our best estimate of the age of the Earth is 4.55 billion years.
It will give similar fossils similar ages, even when the fossils are widely separated.
The half-life is the amount of time it takes for one half of the initial amount of the parent, radioactive isotope, to decay to the daughter isotope.
Thus, if we start out with 1 gram of the parent isotope, after the passage of 1 half-life there will be 0.5 gram of the parent isotope left.
The creation rate of C14 (and so the proportion in the atmosphere) depends on the suns activity - so a lot of dates which assumed a constant rate are known to be wrong.
We can now calibrate this out by looking at C14 in tree rings of a known age - but the charge of "C14 dates are wrong" is used by nutters (sorry creationists) either deliberately or in ignorance.
Other minerals that also show these properties, but are less commonly used in radiometric dating are Apatite and sphene.