Radiometric dating zircon crystals
However, geologists have found that various eruptive stages of the same volcano often extrude lavas exhibiting somewhat different mineral compositions, particularly if an extensive period of time separated the eruptions.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.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.
Lava (properly called magma before it erupts) fills large underground chambers called magma chambers.
Radiometric dating zircon crystals comments