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What is the origin of basalt?
Basalt (UK: /ˈbæs. ɔːlt, -əlt/; US: /bəˈsɔːlt, ˈbeɪˌsɔːlt/) is an aphanitic extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt.
How is basalt formed simple?
It is a kind of igneous rock formed by the cooling of a certain type of molten lava. The lava cools and then hardens into a fine-grained crystalline rock (see lava and magma). Most of the lavas that pour out of volcanoes that make up oceanic islands are basaltic.
What are the 3 ways basalt was formed on Earth?
Most of the basalt found on Earth was produced in just three rock-forming environments: 1) oceanic divergent boundaries, 2) oceanic hotspots, and 3) mantle plumes and hotspots beneath continents.
How long ago did basalt form?
About 1.1 billion years ago
About 1.1 billion years ago during the Proterozoic Eon a great plume of hot mantle rock rose under this area, stretching the crust and erupting many huge basaltic lava flows (black) in the subsiding basin along the Midcontinent Rift System. Note the Earth’s curvature for scale.
How are basalt and granite formed?
Basalt is an igneous, volcanic rock that forms commonly in oceanic crust and parts of continental crust. Granite is an igneous plutonic rock which is very common in continental crust. It forms from subterranean magma chambers that cool and harden beneath the surface and then become exhumed and exposed at the surface.
Does basalt form quickly?
Basalt forms when magma from the ocean surfaces through the crust. It is a very prominent rock and comes from nearly all volcanoes in the ocean. Basalt cools very quickly, in a few weeks or months, which leaves little time for crystals to form.
What environment does basalt form in?
Pillow basalt typically forms at volcanoes at mid-ocean ridges or at oceanic hot-spot volcanoes, such as those that formed the Hawaiian Islands. Basalt forms the crust of all the ocean basins and is therefore the most common rock in the Earth’s crust.
How fast does basalt form?
Pahoehoe, the smooth form of basalt usually travels very slowly–at speeds of only a few meters per hour, averaged over the whole flow. ‘A’a, the rough clinkery form of basalt travels faster, ranging from a few hundred meters per hour up to 10 km per hour on steep slopes.
What are the characteristics of basalt?
Basalt is a dark-colored, fine-grained, igneous rock composed mainly of plagioclase and pyroxene minerals. It most commonly forms as an extrusive rock, such as a lava flow, but can also form in small intrusive bodies, such as an igneous dike or a thin sill.
Where is basalt formed?
Most of Earth’s basalt is produced at divergent plate boundaries on the mid-ocean ridge system (see map). Here convection currents deliver hot rock from deep in the mantle. This hot rock melts as the divergent boundary pulls apart, and the molten rock erupts onto the sea floor.
What are the properties of basalt?
There are various physical properties of Basalt like Hardness, Grain Size, Fracture, Streak, Porosity, Luster, Strength etc which defines it.