Metamorphic and igneous rocks, when subjected to intense heat and pressure, undergo a process of melting. This molten material, known as magma, consists of minerals and other components derived from the parent rock. Understanding the composition and properties of magma is crucial for studying geological processes, such as volcanic eruptions and the formation of new rocks. Magma, upon cooling and solidification, crystallizes to form igneous rocks.
Melting of Metamorphic or Igneous Rock Forms What Substance
The melting of metamorphic or igneous rock forms different substances depending on the composition of the rock and the temperature and pressure conditions under which it melts. In general, the higher the temperature and pressure, the more likely the rock is to melt.
The most common type of rock to melt is granite. Granite is an igneous rock that is composed of quartz, feldspar, and mica. When granite melts, it forms a liquid called magma. Magma is less dense than granite, so it rises to the surface of the Earth. If the magma reaches the surface, it erupts as lava.
Other types of rock that can melt include gneiss, schist, and marble. Gneiss and schist are metamorphic rocks that are formed when igneous or sedimentary rocks are subjected to high temperatures and pressures. Marble is a metamorphic rock that is formed when limestone is subjected to high temperatures and pressures.
When gneiss, schist, or marble melts, it forms a liquid called a melt. Melts are less dense than the rocks from which they are formed, so they rise to the surface of the Earth. If a melt reaches the surface, it erupts as lava.
The composition of the melt depends on the composition of the rock from which it is formed. For example, a melt formed from granite will be rich in silica, while a melt formed from marble will be rich in calcium carbonate.
The temperature and pressure conditions under which a rock melts also affect the composition of the melt. For example, a rock that melts at a high temperature will produce a melt that is richer in silica than a rock that melts at a low temperature.
The following table summarizes the different types of rock that can melt and the substances that they form:
| Rock Type | Melt Type |
|---|---|
| Granite | Magma |
| Gneiss | Melt |
| Schist | Melt |
| Marble | Melt |
Question: What substance forms from the melting of metamorphic or igneous rock?
Answer: The melting of metamorphic or igneous rock forms magma. Magma is a molten or semi-molten rock that is found beneath the Earth’s surface. It is composed of a variety of minerals, including silica, aluminum oxide, and magnesium oxide. When magma cools and solidifies, it forms igneous rock.
Question: What are the different types of magma?
Answer: There are two main types of magma: felsic and mafic. Felsic magma is light in color and has a low silica content. Mafic magma is dark in color and has a high silica content. Felsic magma is typically found in continental crust, while mafic magma is typically found in oceanic crust.
Question: What causes magma to erupt?
Answer: Magma erupts when it rises to the surface of the Earth and escapes through a volcano. The pressure inside the volcano builds up until it is greater than the pressure of the overlying rock. When this happens, the magma erupts through the volcano’s vent. The eruption can be explosive or non-explosive, depending on the composition of the magma and the amount of gas it contains.
Well, there you have it, folks! Metamorphic and igneous rocks melt to form magma, which can then cool and solidify to create new rocks. It’s a fascinating process that’s been happening for billions of years, and it’s responsible for the wide variety of rocks we see on Earth today. Thanks for reading, and be sure to visit again for more rockin’ adventures!