Ultramafic rocks are primarily composed of minerals that are rich in iron and magnesium, with a low silica content. The main minerals found in ultramafic rocks include olivine, pyroxene, and amphibole. These rocks are typically dark in color due to their high iron and magnesium content.
Ultramafic rocks are commonly found in the Earth’s mantle and are often exposed in areas where tectonic activity has pushed them to the surface. One prominent example is the peridotite, which constitutes a significant portion of the upper mantle. Additionally, ultramafic rocks can be found in ophiolite complexes, which are sections of the oceanic crust that have been uplifted and emplaced onto continental crust. In regions where tectonic plates converge, such as subduction zones, ultramafic rocks can also be present as they are often associated with the formation of mountain ranges.