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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.
The formation of pull-apart basins along strike-slip faults causes decompression melting. Advection of melts and heat flux into the lower crust results in partial melting of crustal rock. [16] The buoyant magma rises due to its lower density and is able to exploit weaknesses such as fault planes, using strike-slips as conduits for motion. [4]
Igneous rock (igneous from Latin igneus 'fiery'), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet 's mantle or crust.
Melt rapidly separates from its source rock once the degree of partial melting exceeds 30%. However, usually much less than 30% of a magma source rock is melted before the heat supply is exhausted. [86] Pegmatite may be produced by low degrees of partial melting of the crust. [87]
Magmatism. Geological map showing the Gangdese batholith, which is a product of magmatic activity about 100 million years ago. Magmatism is the emplacement of magma within and at the surface of the outer layers of a terrestrial planet, which solidifies as igneous rocks. It does so through magmatic activity or igneous activity, the production ...
Igneous differentiation. In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The sequence of (usually increasingly silicic) magmas produced by igneous differentiation is ...
Anatexis. Anatexis (via Latin from Greek roots meaning "to melt down") is the partial melting of rocks. [1] Traditionally, anatexis is used specifically to discuss the partial melting of crustal rocks, while the generic term "partial melting" refers to the partial melting of all rocks, in both the crust and mantle. [citation needed]
In continental crust, partial melting occurs when a portion of the solid rock melts into felsic magma. [4] Rocks in the lower crust and the upper mantle are subject to partial melting. The rate of partial melting and the resultant silicate melt composition depend on temperature, pressure, flux addition (water, volatiles) and the source rock ...