Comment: 09:24 - 10:44 (01:20)
Source: Annenberg/CPB Resources - Earth Revealed - 14. Intrusive Igneous Rocks
Keywords: crystal, "David Sigurdson", "Norman Bowen", "calcic plagioclase", mineral, olivine, pyroxene, hornblende, biotite, temperature, plagioclase, potassium, feldspar, biotite, muscovite, quartz, "reaction series"
Our transcription: The first minerals to crystallize are the calcium plagioclases, which would crystallize up about 1,100, a little more than 1,100 degrees Celsius.
Along with the calcic plagioclases we expect to find crystallization of minerals like olivine, but as the temperature falls, different minerals begin to crystallize.
In fact, some of the earlier minerals begin to convert into some of the minerals that crystallize at lower temperatures.
And in discontinuous series, we see olivine being dominated then overtaken by pyroxene, the pyroxene being changed into hornblende, hornblende into biotite.
There's a conversion, usually just a pair of minerals as we go to lower and lower temperatures.
The low temperature minerals in Bowen's Reaction Series consists also of plagioclases.
The continuous series changes from the calcium rich plagioclase to the sodium rich plagioclases.
As we get down to 800 - 700 degrees Celsius, we have more sodic rich plagioclases.
We have minerals like K feldspars, biotite, muscovite, and quartz crystallized.
These are the more felsic constituents of Bowen's Reaction Series.
Geology School Keywords