These minerals would then fall to the bottom of the magma chamber and thus uranium at the top would be depleted. This is a very clever idea. Deep time Geological history of Earth Geological time units. This will date oldest. But how does Bowen's reaction series account for the great diversity of igneous rocks?
I should mention that the decay constants basically a value that indicates how fast a certain radioactive isotope will decay for some of these isotope systems were calculated by assuming that the age of the earth is 4.
But many minerals take in a lot of uranium. They assume that initially the magma was well mixed to assure an even concentration of lead isotopes, but that uranium or thorium were unevenly distributed initially. Lava erupting earlier would come from the top of the magma chamber, and lava erupting later would come from lower down. The 26 Al — 26 Mg chronometer gives an estimate of the time period for formation of primitive meteorites of only a few million years 1. Two kinds of magma and implications for radiometric dating It turns out that magma has two sources, ocean plates and material from the continents crustal rock.