ultrabasic
51Ультраосновные горные породы — ультрабазиты, гипербазиты (a. ultrabasic rocks; н. ultrabasische Gesteine; ф. roches ultrabasiques; и. rocas ultrabasicas), группа магматич. горн. пород c низким содержанием кремнезёма (30 45% SiO2). Пo щёлочности среди ультрабазитов,… …
52Возраст Земли — Возраст Земли  время, которое прошло с момента образования Земли как самостоятельной планеты. Согласно современным научным данным возраст Земли составляет 4,54 миллиардов лет (4,54·109 лет ± 1 %).[1][2][3] Эти данные базируются на… …
53Asia — /ay zheuh, ay sheuh/, n. a continent bounded by Europe and the Arctic, Pacific, and Indian oceans. 2,896,700,000; ab. 16,000,000 sq. mi. (41,440,000 sq. km). * * * I Largest continent on Earth. It is bounded by the Arctic Ocean, the Pacific Ocean …
54kimberlite — /kim beuhr luyt /, n. Petrol. a variety of micaceous peridotite, low in silica content and high in magnesium content, in which diamonds are formed. [1885 90; named after KIMBERLEY, South Africa; see ITE1] * * * or blue ground Dark, heavy, often… …
55New Caledonia — /kal i doh nee euh, dohn yeuh/ 1. an island in the S Pacific, ab. 800 mi. (1290 km) E of Australia. 113,680; 6224 sq. mi. (16,120 sq. km). 2. an overseas territory of France comprising this island and other smaller islands: formerly a penal… …
56ultramafic — /ul treuh maf ik/, adj. Geol. ultrabasic. [1940 45; ULTRA + MAFIC] * * * …
57acid and basic rocks — Division of igneous rocks on the basis of their silicate mineral content, these minerals usually being the most abundant in such rocks. Rocks are described as acid, intermediate, basic, and ultrabasic, in order of decreasing silica content,… …
58forsterite-fayalite series — Most important minerals in the olivine family and possibly the most important constituents of the Earth s mantle. These minerals occur as green to yellow, glassy crystals in many basic and ultrabasic rocks (see acid and basic rocks) and are also… …
59oxide mineral — Any naturally occurring inorganic compound with a structure based on close packed oxygen atoms in which smaller, positively charged metal or other ions occur. Oxide minerals are common in all rock types, whether igneous, sedimentary, or… …
60chemical element — Introduction also called element, any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed. This article considers the… …
