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.
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.
A pioneering investigation into the crystallization of magma was carried out by N. At successively lower temperature, other minerals begin to crystallize as shown in Figure 3.6.
During the last stage of crystallization, after most of the magma has solidified, the remaining melt will form the minerals quartz, muscovite mica, and potassium feldspar.
Although these minerals crystallize in the order shown, this sequence is not a true reaction series.
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.