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The word lava comes from Italian and is probably derived from the Latin word labes, which means a fall or slide. [2] [3] An early use of the word in connection with extrusion of magma from below the surface is found in a short account of the 1737 eruption of Vesuvius, written by Francesco Serao, who described "a flow of fiery lava" as an analogy to the flow of water and mud down the flanks of ...
Whereas temperatures in common silicate lavas range from about 800 °C (1,470 °F) for felsic lavas to 1,200 °C (2,190 °F) for mafic lavas, [24] the viscosity of the same lavas ranges over seven orders of magnitude, from 10 4 cP (10 Pa⋅s) for mafic lava to 10 11 cP (10 8 Pa⋅s) for felsic magmas. [24]
A silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula [SiO (4-2x)− 4− x ] n , where 0 ≤ x < 2 .
A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include basalt, diabase and gabbro. Mafic rocks often also contain calcium-rich varieties of plagioclase ...
Felsic refers to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. Molten felsic magma and lava is more viscous than molten mafic magma and lava. Felsic magmas and lavas have lower temperatures of melting and solidification than mafic magmas and lavas.
Whereas most lavas are rich in silicate minerals, the natrocarbonatite lavas of Ol Doinyo Lengai are rich in two rare sodium and potassium carbonate minerals, nyerereite and gregoryite. [3] Due to this unusual composition, the lava is erupted at relatively low temperatures (approximately 500–600 °C). [4]
They are (or were) the hottest lavas, and were probably more fluid than common mafic lavas, with a viscosity less than a tenth that of hot basalt magma. [66] Mafic lava flows show two varieties of surface texture: ʻAʻa (pronounced ) and pāhoehoe ([paːˈho.eˈho.e]), both Hawaiian words. ʻAʻa is characterized by a rough, clinkery surface ...
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).