What is the origin of basaltic magma?
Basaltic magmas within Earth are thought to originate from the upper mantle. The chemistry of basalts thus provides clues to conditions deep in Earth’s interior.
What is the origin of basalt?
Basalts are formed by the rapid cooling of basaltic lava, equivalent to gabbro-norite magma, from interior of the crust and exposed at or very close to the surface of Earth. These basalt flows are quite thick and extensive, in which gas cavities are almost absent.
How are basaltic magmas thought to be formed quizlet?
How are basaltic magmas thought to be formed? A basaltic pond of magma becomes trapped below continental crust and partially melts this silica-rich crust into a granitic magma.
What is the origin of andesite?
Andesite derives its name from the Andes Mountains of South America. In the Andes it occurs as lava flows interbedded with ash and tuff deposits on the steep flanks of stratovolcanoes.
How do basaltic plateaus originate?
Lava plateaus are formed by highly fluid basaltic lava during numerous successive eruptions through numerous vents without violent explosions (quiet eruptions). This region, known as the Thulean Plateau, is generally believed to have been broken up by foundering of the Earth’s crust to form the present ocean basin.
What is basaltic magma made of?
Lesson Summary Basaltic lava, or mafic lava, is molten rock enriched in iron and magnesium and depleted in silica. Basaltic magmas are formed by exceeding the melting point of the mantle either by adding heat, changing its composition, or decreasing its pressure.
What type of eruption does basaltic magma most likely produce?
There are two major groupings of eruptions: effusive and explosive. Effusive eruption differs from explosive eruption, wherein magma is violently fragmented and rapidly expelled from a volcano. Effusive eruptions are most common in basaltic magmas, but they also occur in intermediate and felsic magmas.
Where did the magma from which this rock formed likely originate?
Therefore, the magma from which this rock formed likely originated in the mantle.
Which magma composition basaltic or andesitic would be most likely to form a sill?
Most sills are of mafic to intermediate compositions (basaltic to andesitic), that is, composed of low-viscosity magma. In contrast, felsic intrusions (rhyolitic) dominantly exhibit laccolithic shape due to the high viscosity of the magma (Bunger and Cruden, 2011).
What is the origin of magma in igneous rock?
In igneous rock: Origin of magmas Basaltic magmas that form the oceanic crust of the Earth are generated in the asthenosphere at a depth of about 70 kilometres. The mantle rocks located at depths from about 70 to 200 kilometres are believed to exist at temperatures slightly above their melting point,….
What are the source rocks for basaltic magma?
Source rocks for the partial melts that produce basaltic magma probably include both peridotite and pyroxenite. The shape, structure and texture of a basalt is diagnostic of how and where it erupted—for example, whether into the sea, in an explosive cinder eruption or as creeping pāhoehoe lava flows, the classic image of Hawaiian basalt eruptions.
How are magmas formed in the mantle?
On Earth, most basalt magmas have formed by decompression melting of the mantle. The high pressure in the upper mantle (due to the weight of the overlying rock) raises the melting point of mantle rock, so that almost all of the upper mantle is solid. However, mantle rock is ductile (the solid rock slowly deforms under high stress).
Where do magmas come from in the asthenosphere?
In igneous rock: Origin of magmas Basaltic magmas that form the oceanic crust of Earth are generated in the asthenosphere at a depth of about 70 kilometres. The mantle rocks located at depths from about 70 to 200 kilometres are believed to exist at temperatures slightly above their melting point, and…