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One of the main sources of information about the Earth's composition comes from understanding the relationship between peridotite and basalt melting. Peridotite makes up most of Earth's mantle. Basalt, which is highly concentrated in the Earth's oceanic crust, is formed when magma reaches the Earth's surface and cools down at a very fast rate. [1]
Basalt (UK: / ˈ b æ s ɒ l t,-ɔː l t,-əl t /; [1] [2] US: / b ə ˈ s ɔː l t, ˈ b eɪ s ɔː l t /) [3] is an aphanitic (fine-grained) 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.
A parental melt is a magma composition from which the observed range of magma chemistries has been derived by the processes of igneous differentiation. It need not be a primitive melt. For instance, a series of basalt lava flows is assumed to be related to one another.
Partially molten basalt in the mantle wedge moves upwards until it reaches the base of the overriding crust. Once there, the basaltic melt can either underplate the crust, creating a layer of molten material at its base, or it can move into the overriding plate in the form of dykes. If it underplates the crust, the basalt can (in theory) cause ...
This is similar to the lowering of the melting point of ice when it is mixed with salt. The first melt is called the eutectic and has a composition that depends on the combination of minerals present. [78] For example, a mixture of anorthite and diopside, which are two of the predominant minerals in basalt, begins to melt at about 1274 °C ...
Partial melting is the phenomenon that occurs when a rock is subjected to temperatures high enough to cause certain minerals to melt, but not all of them. Partial melting is an important part of the formation of all igneous rocks and some metamorphic rocks (e.g., migmatites), as evidenced by a multitude of geochemical, geophysical and petrological studies.
Within the field of geology, Bowen's reaction series is the work of the Canadian petrologist Norman L. Bowen, [1] who summarized, based on experiments and observations of natural rocks, the sequence of crystallization of common silicate minerals from typical basaltic magma undergoing fractional crystallization (i.e. crystallization wherein early-formed crystals are removed from the magma by ...
At the mid-ocean divergent boundaries new magma is produced by mantle upwelling and a shallow melting zone. This juvenile basaltic magma is an early phase of the igneous portion of the cycle. As the tectonic plates on either side of the ridge move apart the new rock is carried away from the ridge, the interaction of heated circulating seawater ...