DECOMPRESSION MELTING Meaning and
Definition
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Decompression melting refers to the process of melting beneath the Earth's surface due to a reduction in pressure. It occurs when hot, solid rocks rise to shallower depths within the Earth's mantle or crust, resulting in a decrease in pressure on the rocks. As the pressure decreases, the melting point of rocks decreases as well, causing them to melt and form magma.
This phenomenon commonly occurs at divergent plate boundaries, such as mid-ocean ridges, where tectonic plates move apart from each other, creating a gap in the Earth's crust. As the plates separate, the underlying asthenosphere rises to fill the gap, causing a decrease in pressure. This lowering of pressure enables the rocks to undergo decompression melting, leading to the creation of basaltic magma.
Additionally, decompression melting can occur during the uplift of mountain ranges or along hotspots, where plumes of abnormally hot material rise through the mantle towards the surface. As the plume ascends, the overlying mantle undergoes decompression, triggering melting and the formation of magma chambers. This process is often responsible for the volcanic activity associated with hotspots.
Decompression melting plays a crucial role in the Earth's geology by providing a mechanism for the production of magma and the subsequent formation of igneous rocks. Understanding this process helps scientists comprehend the evolution of the Earth's crust, the movement of tectonic plates, and the formation of various geologic features, such as volcanoes and oceanic crust.
Etymology of DECOMPRESSION MELTING
The etymology of the word "decompression melting" can be understood by breaking down the individual parts of the term.
1. Decompression: The word "decompression" is derived from the prefix "de-" meaning to remove, reverse, or undo, and the word "compression" referring to the act of pressing or compacting something. In the context of geology, decompression refers to the reduction of pressure on a substance, specifically rocks.
2. Melting: The word "melting" comes from the Old English word "meltan" which means to become liquid or dissolve as a result of increased heat. In the field of geology, melting refers to the process of a solid substance, such as rocks or minerals, transforming into a liquid state due to the application of heat.
