At any rate, there will be some effects of this nature that will produce some kinds of changes in concentration of uranium and thorium relative to lead from the top to the bottom of a magma chamber. When dating older objects, namely rocks, it is necessary to use other isotopes that take a much longer time to decay. How big is a vicinity? Some of the patterns that are produced may appear to give valid radiometric dates. There are a number of uranium compounds with different melting points, and in general it seems that the ones with the highest melting points are more stable.
By measuring the parent isotope radioactive and the daughter isotope radiogenic in a system for example, a rock , we can tell how long the system has been closed in our example, when the rock formed. A faster method involves using particle counters to determine alpha, beta or gamma activity, and then dividing that by the number of radioactive nuclides. Answer 6: Click Here to return to the search form. I believe that the same considerations apply to concordia and discordia, but am not as familiar with them. Here is yet another mechanism that can cause trouble for radiometric dating: As lava rises through the crust, it will heat up surrounding rock.