Bowen's reaction series
Discontinuous Series (Mafic minerals) | Continuous Series (Felsic minerals) | High | |||||||||||||||||||||
Olivine | Plagioclase (Calcium rich) | ||||||||||||||||||||||
Pyroxene | |||||||||||||||||||||||
Amphibole | |||||||||||||||||||||||
Biotite (Black Mica) | Plagioclase (Sodium rich) | Relative Crystallization Temperature | |||||||||||||||||||||
K-feldspar ) | |||||||||||||||||||||||
Muscovite (White Mica) | |||||||||||||||||||||||
Quartz (Felsic mineral) | |||||||||||||||||||||||
Low | |||||||||||||||||||||||
Within the field of
Description
The series is divided into two branches, the continuous (felsic minerals: feldspars) and the discontinuous (mafic minerals). The minerals at the top of the illustration (given aside) are first to crystallize and so the temperature gradient can be read to be from high to low with the high-temperature minerals being on the top and the low-temperature ones on the bottom. The branch on the right of the illustration is the continuous one (with continuous solid solutions of felsic minerals) and results in progressively sodium-rich plagioclase at lowering temperatures. In the discontinuous series mafic minerals such as olivine will first crystallize at a higher temperature, as magma cools. However, if they are not precipitated (settled) out, the composition of the magma does not change and as the magma further cools the olivine will recrystallise as pyroxene.
Since the surface of the Earth is a low temperature environment compared to the zones of rock formation, the chart also reflects the relative stability of minerals, with the ones at bottom being most stable and the ones at top being quickest to weather, known as the Goldich dissolution series. This is because minerals are most stable in the temperature and pressure conditions closest to those under which they had formed.
References
- S2CID 73262622.
- ^ Bowen, N.L. (1956). The Evolution of the Igneous Rocks. Canada: Dover. pp. 60–62.
- doi:10.1086/622871.
- ISBN 0-471-80580-7