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.

Of course, there are many problems with such dating methods, such as parent or daughter substances entering or leaving the rock, as well as daughter product being present at the beginning.

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These long time periods are computed by measuring the ratio of daughter to parent substance in a rock and inferring an age based on this ratio.

This age is computed under the assumption that the parent substance (say, uranium) gradually decays to the daughter substance (say, lead), so the higher the ratio of lead to uranium, the older the rock must be.

On the upper left branch of this reaction series, olivine, the first mineral to form, Ml] react with the remaining melt to become pyroxene.

This reaction will continue until the last mineral in the series, biotite mica, is formed.

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.Lava (properly called magma before it erupts) fills large underground chambers called magma chambers.Most people are not aware of the many processes that take place in lava before it erupts and as it solidifies, processes that can have a tremendous influence on daughter to parent ratios.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.But at the same time, it will be enriched in the elements contained in the later forming minerals, namely sodium and potassium.