Plagioclase feldspars crystallize at temperatures between 1300 and 600°C because they can be either calcium-rich or sodium-rich, which influences the temperature at which they begin to crystallize from a molten state.
The reason plagioclase feldspars crystallize at temperatures between 1300 and 600°C is because they can be either calcium-rich or sodium-rich. These minerals are essential components in both mafic and felsic igneous rocks, and they crystallize at high temperatures early in the cooling process. Plagioclase is often accompanied by other minerals such as quartz, which crystallizes at lower temperatures.
For plagioclase feldspars, the variation between being calcium-rich or sodium-rich depends on their chemical composition, which in turn influences the temperature at which they begin to crystallize from molten rock. This range of crystallization temperatures allows plagioclase feldspars to form under various geological conditions deep below the Earth's surface.
So, plagioclase feldspars crystallize through a broad range of temperatures due to their ability to vary in chemical composition from being calcium-rich to sodium-rich, accommodating different cooling histories and environments within the Earth's crust.