Ultramafics

Ultramafics are a group of igneous rocks that are extremely rich in magnesium and iron, and are typically poor in silica. They are formed from the partial melting of the Earth's mantle, which is composed of ultramafic minerals such as olivine, pyroxene, and amphibole. Ultramafics are characterized by their dark color, which is due to the presence of iron and magnesium-rich minerals. They are often found in ophiolite complexes, which are fragments of oceanic crust and mantle that have been obducted onto continental margins.

There are two main types of ultramafics: peridotites and pyroxenites. Peridotites are the most common type of ultramafic rock and are composed primarily of olivine and pyroxene. They are often found in the mantle section of ophiolite complexes. Pyroxenites are composed primarily of pyroxene and are often found in the crustal section of ophiolite complexes.

Ultramafics are important in the study of the Earth's mantle because they provide a direct sample of mantle material. They are also important in the study of ore deposits, as many economically important metals such as nickel, chromium, and platinum are concentrated in ultramafic rocks. Ultramafics are also important in the study of the Earth's early history, as they provide evidence of the early differentiation of the Earth's mantle.