Ultramafic Rock
Ultramafic (also referred to as ultrabasic) rocks are igneous and meta-igneous rocks with very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed of usually greater than 90% mafic minerals (dark colored, high magnesium and iron content). The Earth's mantle is composed of ultramafic rocks.
Read more about Ultramafic Rock: Intrusive Ultramafic Rocks, Volcanic Ultramafic Rocks, Ultrapotassic Ultramafic Rocks, Metamorphic Ultramafic Rocks, Distribution in Space and Time, Soil and Regolith Developed On Ultramafic Rock
Famous quotes containing the word rock:
“Compare the history of the novel to that of rock ‘n’ roll. Both started out a minority taste, became a mass taste, and then splintered into several subgenres. Both have been the typical cultural expressions of classes and epochs. Both started out aggressively fighting for their share of attention, novels attacking the drama, the tract, and the poem, rock attacking jazz and pop and rolling over classical music.”
—W. T. Lhamon, U.S. educator, critic. “Material Differences,” Deliberate Speed: The Origins of a Cultural Style in the American 1950s, Smithsonian (1990)