Radioactive dating in massachusetts
The straight line takes the zircons off the concordia. The disturbing event affects the zircons unequally, stripping all the lead from some, only part of it from others and leaving some untouched.The results from these zircons therefore plot along that straight line, establishing what is called a discordia. If a 1500-million-year-old rock is disturbed to create a discordia, then is undisturbed for another billion years, the whole discordia line will migrate along the curve of the concordia, always pointing to the age of the disturbance.Of all the isotopic dating methods in use today, the uranium-lead method is the oldest and, when done carefully, the most reliable.Unlike any other method, uranium-lead has a natural cross-check built into it that shows when nature has tampered with the evidence.A radioactive isotope is an isotope whose nucleus tends to release particles, radiant energy, or both; Radioactive dating is a technique for determining the age of material by measuring the amount of a particular radioactive isotope the material contain.No, radioactive dating does not produce exact results.Uranium comes in two common isotopes with atomic weights of 235 and 238 (we'll call them 235U and 238U).
But results can be gotten that are surprisingly accurate.
As a "for instance" we might look at uranium-lead dating.
This dating method can deliver results accurate to a million or two years in a billion years. Radioactive dating is also known as Radiometric dating.
But now imagine that some geologic event disturbs things to make the lead escape.
That would take the zircons on a straight line back to zero on the concordia diagram.
The radioactive dating relies on spontaneous decomposition into other element.