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Why the expansion of rock is important in the formation of magma?
All magma forms through melting of pre-existing rock. Mantle convection occurs because deep within the earth, radioactive decay raises the temperature of rock, making it expand. This expansion lowers the rock’s density, causing it to rise, or convect.
What is the importance of magma formation?
Magma is extremely hot—between 700° and 1,300° Celsius (1,292° and 2,372° Fahrenheit). This heat makes magma a very fluid and dynamic substance, able to create new landforms and engage physical and chemical transformations in a variety of different environments.
What causes magma to expand?
Magma forms from partial melting of mantle rocks. As the rocks move upward (or have water added to them), they start to melt a little bit. As they rise, gas molecules in the magma come out of solution and form bubbles and as the bubbles rise they expand.
What does the formation of magma depend on?
Magma composition depends on the composition of the rocks that melted to form the magma, and on the conditions under which the melting happened. Most igneous rock in Earth’s crust comes from magmas that formed through partial melting of existing rock, either in the upper mantle or the crust.
What are the sources of magma?
Magma is produced by melting of the mantle or the crust in various tectonic settings, which on Earth include subduction zones, continental rift zones, mid-ocean ridges and hotspots.
What will happen after magma is formed?
Magma cools and crystallizes to form igneous rock. Igneous rock undergoes weathering (or breakdown) to form sediment. As the sedimentary rock is buried under more and more sediment, the heat and pressure of burial cause metamorphism to occur. This transforms the sedimentary rock into a metamorphic rock.
Do you need to melt rocks to form magma?
In order for magma to form, wet or dry melting of rocks or minerals must occur. Dry melting occurs when minerals or rocks, with no carbon dioxide or water in them, are heated to a specific temperature.
What 3 things affect the formation of magma?
The factors that mainly affect in the formation of magma can be summarized into three: Temperature, Pressure and composition.
- Temperature plays a role in the formation of the melts in the magma.
- Pressure can affect the shape and formation of melts.
What are the special conditions required for the formation of magma?
Wet and Dry Melting In order for magma to form, wet or dry melting of rocks or minerals must occur. Dry melting occurs when minerals or rocks, with no carbon dioxide or water in them, are heated to a specific temperature. This temperature increases as pressure in the Earth’s layers increases.
How does the composition of magma depend on the Rock It is formed from?
The composition of magma depends on the rock it was formed from (by melting), and the conditions of that melting. Magmas derived from the mantle have higher levels of iron, magnesium, and calcium, but they are still likely to be dominated by oxygen and silicon.
Why is the presence of magma important to geologists?
Most of the mantle and crust are solid, so the presence of magma is crucial to understanding the geology and morphology of the mantle. Differences in temperature, pressure, and structural formations in the mantle and crust cause magma to form in different ways.
Where does magma form in a subduction zone?
Exploring magma formation. Andesite is a type of rock that is thought to form on the edge of tectonic plates in a subduction zone. The subduction zone is where one plate is being forced under another and the subducting plate then melts in the hot mantle.
How does magma form at convergent and divergent boundaries?
At convergent boundaries magma is formed where water from a subducting plate acts as a flux to lower the melting temperature of the adjacent mantle rock. At divergent boundaries magma forms because of decompression melting. Decompression melting also takes place within a mantle plume.