Final answer:
Partial melting of the ultramafic rock peridotite typically generates mafic magma, which is rich in iron and magnesium. This occurs in the mantle where high temperatures facilitate partial melting of the source rock.
Step-by-step explanation:
Partial melting of ultramafic rock, such as peridotite in Earth's mantle, typically generates a mafic magma in composition. This mafic magma is rich in magnesium and iron and often contains an abundance of minerals such as pyroxene, olivine, and amphibole. The partial melting of peridotite, which occurs due to the high temperatures in the mantle, leads to the formation of mafic magma, which is less silica-rich compared to the source rock.
The properties of the ultramafic rock peridotite, which include a composition dominated by the iron- and magnesium-rich silicate minerals, are crucial in the generation of this type of magma. When it comes to igneous rock classification based on mineral content, rocks with substantial amounts of olivine and pyroxene are categorized as ultramafic, while those with less silica and more ferromagnesian minerals such as those found in oceanic crust are categorized as mafic.