Search results
Results from the WOW.Com Content Network
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 ...
The lavas of different volcanoes, when cooled and hardened, differ much in their appearance and composition. If a rhyolite lava-stream cools quickly, it can quickly freeze into a black glassy substance called obsidian. When filled with bubbles of gas, the same lava may form the spongy appearing pumice. Allowed to cool slowly, it forms a light ...
Basalt is the most common extrusive igneous rock [9] and forms lava flows, lava sheets and lava plateaus. Some kinds of basalt solidify to form long polygonal columns. The Giant's Causeway in Antrim, Northern Ireland is an example. The molten rock, which typically contains suspended crystals and dissolved gases, is called magma. [10]
Stratovolcano. Mount Rainier, a 4,392 m (14,411 ft) stratovolcano, the highest point in the US state of Washington. Exposed internal structure of alternating layers of lava and pyroclastic rock in the eroded Broken Top stratovolcano in Oregon. A stratovolcano, also known as a composite volcano, is a conical volcano built up by many alternating ...
Magma chamber. A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it upwards. [1] If the magma finds a path to the surface, then the result will be a volcanic ...
The ridges and patterns on top of the lava field show the direction of the lava channels and the often active lava tubes that may be underneath the solidified "crust." [1] It can also reveal whether the lava flow can be classified as pāhoehoe or 'a'ā. The two main types of lava field structures are defined as sheet flow lava and pillow lava ...
An example is the massive Level Mountain shield volcano in northern British Columbia, Canada, which covers an area of 1,800 km 2 (690 sq mi) and a volume of 860 km 3 (210 cu mi). [ 1 ] Perhaps the most extensive of all the subaerial basaltic plateaus existed during the Paleogene [ 2 ] and possibly extended over 1,800,000 km 2 (690,000 sq mi) of ...
Magma that is extruded as lava is extremely dry, but magma at depth and under great pressure can contain a dissolved water content in excess of 10%. Water is somewhat less soluble in low-silica magma than high-silica magma, so that at 1,100 °C and 0.5 GPa , a basaltic magma can dissolve 8% H 2 O while a granite pegmatite magma can dissolve 11% ...