PARTIAL MELTING Meaning and
Definition
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Partial melting is a geological process in which only a portion of a mineral or rock undergoes melting, while the remaining part remains solid. It occurs when the temperature of a material exceeds its melting point, but due to the presence of impurities or minerals with higher melting points, complete melting does not occur.
The process of partial melting plays a crucial role in Earth's tectonic processes. It commonly occurs in the Earth's mantle or beneath the Earth's crust, where rock formations are subjected to immense heat and pressure. As the temperature rises, certain minerals or portions of a rock composition may reach their melting point, beginning to liquefy while others remain solid. The melting minerals typically have lower melting points compared to the rest of the rock, allowing them to transform into a molten state while the surrounding material remains intact.
This phenomenon is significant in the formation of igneous rocks, which are formed from the solidification of molten material. Partial melting leads to the creation of magma, a mixture of melted minerals and remaining solid rock. Magma can then rise towards the Earth's surface through various mechanisms such as volcanic activity or intrusion into existing rock formations, eventually solidifying to form igneous rocks.
Partial melting is also responsible for the formation of different mineral assemblages within rocks, as the melting process segregates minerals based on their melting points and chemical compositions. This segregation can result in the formation of unique rock textures and compositions, ultimately contributing to the diversity observed in Earth's crust.
Etymology of PARTIAL MELTING
The word "partial" originated from the Latin word "partialis", which means "part" or "portion". It entered the English language around the late 14th century. On the other hand, "melting" comes from the Middle English word "melte", which can be traced back to the Old English word "meltian", meaning "to dissolve" or "liquefy". The combination of these two words resulted in "partial melting", referring to the process of only a portion of a substance or material melting while the rest remains solid.
