Final answer:
The four major magma types based on silica content are felsic, intermediate, mafic, and ultramafic, each with distinct mineral compositions and associated igneous rocks.
Step-by-step explanation:
The four major magma types based on the silica (SiO2) content are felsic, intermediate, mafic, and ultramafic. Each type has a distinctive silica content and mineral composition which affects the properties and types of igneous rocks they form upon solidification.
Felsic magma is high in silica, which means it can have more than 65% SiO2. This type of magma usually forms light-colored rocks like granite and rhyolite, characterized by minerals such as quartz and potassium feldspar. Intermediate magma contains 53-65% silica and commonly forms rocks like andesite and diorite.
Mafic magma has a lower silica content (45-52%) and typically forms darker rocks such as basalt and gabbro. This magma contains minerals like pyroxene and calcium-rich plagioclase. The last category, ultramafic magma, contains less than 45% silica and is rich in minerals like olivine and pyroxene, often crystallizing into rocks like peridotite.
The cooling rate and location of solidification also dictate whether the igneous rocks have a coarse-grained (intrusive) or fine-grained (extrusive) texture. Ultimately, the silica content plays a consequential role in determining the characteristics of the igneous rocks formed from magma.