A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
- VolcanoKomatiite is a type of ultramafic mantle-derived volcanic rock defined as having crystallised from a lava of at least 18 wt% MgO.
- KomatiiteLava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from 800 to 1200 C. The volcanic rock resulting from subsequent cooling is also often called lava.
- LavaUltramafic lavas, such as komatiite and highly magnesian magmas that form boninite, take the composition and temperatures of eruptions to the extreme.
- LavaKomatiite volcano morphology is interpreted to have the general form and structure of a shield volcano, typical of most large basalt edifices, as the magmatic event which forms komatiites erupts less magnesian materials.
- KomatiiteSome erupted magmas contain ≤45% silica and produce ultramafic lava. Ultramafic flows, also known as komatiites, are very rare; indeed, very few have been erupted at the Earth's surface since the Proterozoic, when the planet's heat flow was higher. 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.
- Volcano3 related topics with Alpha
Magma
1 linksMolten or semi-molten natural material from which all igneous rocks are formed.
Molten or semi-molten natural material from which all igneous rocks are formed.
Following its ascent through the crust, magma may feed a volcano and be extruded as lava, or it may solidify underground to form an intrusion, such as a dike, a sill, a laccolith, a pluton, or a batholith.
Ultramafic magmas, such as picritic basalt, komatiite, and highly magnesian magmas that form boninite, take the composition and temperatures to the extreme.
Pillow lava
1 linksPillow lavas are lavas that contain characteristic pillow-shaped structures that are attributed to the extrusion of the lava underwater, or subaqueous extrusion.
Pillow lavas are commonly of basaltic composition, although pillows formed of komatiite, picrite, boninite, basaltic andesite, andesite, dacite or even rhyolite are known.
They occur wherever lava is extruded underwater, such as along marine hotspot volcano chains and the constructive plate boundaries of mid-ocean ridges.
Tuff
0 linksTuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption.
2) Lava, the name of magma when it emerges and flows over the surface
Komatiite tuffs are found, for example, in the greenstone belts of Canada and South Africa.