Faulty fossil dating
To me it has been a real eye opener to see all the processes that are taking place and their potential influence on radiometric dating.
Radiometric dating is largely done on rock that has formed from solidified lava.
Bowen also demonstrated that if a mineral remained in the melt after it had crystallized, it would react with the remaining melt and produce the next mineral in the sequence shown in Figure 3.6.
For this reason, this arrangement of minerals became known as Bowen's reaction series.
The general idea is that many different minerals are formed, which differ from one another in composition, even though they come from the same magma.
The mineral makeup of an igneous rock is ultimately determined by the chemical composition of the magma from which it crystallized.
But at the same time, it will be enriched in the elements contained in the later forming minerals, namely sodium and potassium.
Further, the silicon content of the melt becomes enriched toward the latter stages of crystallization.
For example, at the stage when about 50 percent of the magma has solidified, the melt will be greatly depleted in iron, magnesium, and calcium, because these elements are found in the earliest formed minerals.This left branch is called a discontinuous reaction series because each mineral has a different crystalline structure.Recall that olivine is composed of a single tetrahedra and that the other minerals in this sequence are composed of single chains, double chains, and sheet structures, respectively.Such processes can cause the daughter product to be enriched relative to the parent, which would make the rock look older, or cause the parent to be enriched relative to the daughter, which would make the rock look younger.This calls the whole radiometric dating scheme into serious question.
Geologists assert that older dates are found deeper down in the geologic column, which they take as evidence that radiometric dating is giving true ages, since it is apparent that rocks that are deeper must be older.