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Peridotite, a type of ultramafic rock. Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are usually composed of greater than 90% mafic minerals (dark colored, high magnesium and iron content).
The Goldschmidt classification, [1] [2] developed by Victor Goldschmidt (1888–1947), is a geochemical classification which groups the chemical elements within the Earth according to their preferred host phases into lithophile (rock-loving), siderophile (iron-loving), chalcophile (sulfide ore-loving or chalcogen-loving), and atmophile (gas-loving) or volatile (the element, or a compound in ...
Magmatism is the emplacement of magma within and at the surface of the outer layers of a terrestrial planet, which solidifies as igneous rocks. It does so through magmatic activity or igneous activity, the production, intrusion and extrusion of magma or lava. Volcanism is the surface expression of magmatism.
Chromitite and anorthosite layered igneous rocks in Critical Zone UG1 of the Bushveld Igneous Complex at the Mononono River outcrop, near Steelpoort, South Africa. A layered intrusion is a large sill-like body of igneous rock which exhibits vertical layering or differences in composition and texture.
Carbonatite lava at Ol Doinyo Lengai volcano, Tanzania. Carbonatite (/ k ɑːr ˈ b ɒ n ə ˌ t aɪ t /) is a type of intrusive or extrusive igneous rock defined by mineralogic composition consisting of greater than 50% carbonate minerals. [1]
Serpentinite is a metamorphic rock composed predominantly of serpentine group minerals formed by serpentinization of mafic or ultramafic rocks. The ancient origin of the name is uncertain, it may be from the similarity of its texture or color to snake skin. [1] Greek pharmacologist Dioscorides (AD 50) recommended eating this rock to prevent ...
Ultrapotassic igneous rocks are a class of rare, volumetrically minor, generally ultramafic or mafic silica-depleted igneous rocks. While there are debates on the exact classifications of ultrapotassic rocks, they are defined by using the chemical screens K 2 O/Na 2 O > 3 in much of the scientific literature. [ 1 ]
For example, carbonatite tephra found at Oldoinyo Lengai (a volcano in the East African Rift Valley) has buried and preserved fossilized footprints of humans near the site of the eruption. [10] Under certain conditions, volcanic blocks can be preserved for billions of years [ citation needed ] and can travel up to 400 km away from the eruption.