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Amygdules or amygdales form when the gas bubbles or vesicles in volcanic lava (or other extrusive igneous rocks) are infilled with a secondary mineral such as calcite, quartz, chlorite or one of the zeolites. Rocks containing amygdules can be described as amygdaloidal. anatexis Melting of pre-existing rock. Compare metatexis, diatexis, and ...
Complex volcano – Landform of more than one related volcanic centre; Cryptodome – Roughly circular protrusion from slowly extruded viscous volcanic lava; Cryovolcano – Type of volcano that erupts volatiles such as water, ammonia or methane, instead of molten rock; Diatreme – Volcanic pipe associated with a gaseous explosion
Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks. For these ...
A unit of area traditionally defined as the area of a plot of land one chain (66 feet) by one furlong (660 feet), equivalent to 43,560 square feet (0.001563 sq mi; 4,047 m 2), or about 0.40 hectare. active volcano A volcano that is currently erupting, or one that has erupted within the last 10,000 years (the Holocene) or during recorded history ...
The word volcano (UK: /vɒlˈkeɪnəʊ/; and US /vɔlˈkeɪnoʊ/) originates from the early 17th century, derived from the Italian vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from latin volcānus or vulcānus referring to Vulcan, the god of fire in Roman mythology.
Vesicles are found towards the top of a pillow (because the gas trapped as part of the rock is less dense than its solid surroundings). The pillow structures show a convex (rounded) upper surface. The pillows might have a tapered base downwards, as they may have molded themselves to any underlying pillows during their formation.
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 ...
This glossary of geography terms is a list of definitions of terms and concepts used in geography and related fields, including Earth science, oceanography, cartography, and human geography, as well as those describing spatial dimension, topographical features, natural resources, and the collection, analysis, and visualization of geographic ...