Melting Points of Rocks

Igneous rocks form through the crystallization of magma. There is a considerable range of melting temperatures for different compositions of magma. All the silicates are molten at about 1200°C and all are solid when cooled to about 600°C. Often the silicates are grouped as high, medium and low-melting point solids.

ApproximateTemperature (°C)Minerals which are molten
1200
All molten
1000
Olivine, pyroxene, Ca-rich plagioclase
800
Amphibole, Ca/Na- plagioclase
600
Quartz, K-feldspar, Na-plagioclase, micas.

The pattern shown above where different kinds of minerals crystallize at different temperatures is further developed in the Bowen reaction series. The crystallization temperatures play a large role in the development of the different kinds of igneous rocks upon the cooling of magma.

Index

Igneous rock concepts

Reference
Lutgens & Tarbuck
Ch 3
 
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