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How does thermal metamorphism occur?
Thermal or Contact Metamorphism Heat flows from the magma into the wall rock, for heat always flows from hotter to colder materials. As a consequence, the magma cools and solidifies while the wall rock heats up. Contact metamorphism occurs anywhere that the intrusion of plutons occurs.
At what temperature does metamorphism occur?
Metamorphism, therefore occurs at temperatures and pressures higher than 200oC and 300 MPa. Rocks can be subjected to these higher temperatures and pressures as they are buried deeper in the Earth. Such burial usually takes place as a result of tectonic processes such as continental collisions or subduction.
Why is temperature important in metamorphism?
The temperature that the rock is subjected to is a key variable in controlling the type of metamorphism that takes place. Some minerals will crystallize into different polymorphs (same composition, but different crystalline structure) depending on the temperature and pressure.
What is the role of heat to metamorphism?
heat and pressure. As these bodies cool they release heat to the surrounding country rock, leading to metamorphism. At the extreme end of metamorphism melting takes place. The melting temperature for a rock ranges from a low of 700-800 degrees C to as high at 1000 degrees C.
At what temperature does diagenesis end and metamorphism begin?
Metamorphism typically occurs between diagenesis (maximum 200°C), and melting (~850°C).
Where does metamorphism usually happen?
Although metamorphic rocks typically form deep in the planet’s crust, they are often exposed on the surface of the Earth. This happens due to geologic uplift and the erosion of the rock and soil above them. At the surface, metamorphic rocks will be exposed to weathering processes and may break down into sediment.
What are the 3 types of metamorphism?
There are three ways that metamorphic rocks can form. The three types of metamorphism are Contact, Regional, and Dynamic metamorphism. Contact Metamorphism occurs when magma comes in contact with an already existing body of rock.
What are the 5 factors that influence metamorphism?
Factors Controlling Metamorphism
- Temperature and pressure. Temperature and pressure are important factors in determining the new minerals that form in a metamorphic rock.
- Water.
- Geostatic pressure.
- Differential stress.
- Figure 1.
- Differential Stress.
- Compressive stress.
- Figure 2.
What are the three agents of metamorphism?
The most important agents of metamorphism include temperature, pressure, and fluids.
What are the two most important source of heat for metamorphism?
Heat that results in metamorphism is the result igneous intrusions and from deep burial. The two most important sources of heat for metamorphism are: A) intrusive magma bodies and deep burial.
What are the three causes of metamorphism?
There are 3 main agents that cause metamorphism. Factors that cause an increase in Temperature, Pressure, and Chemical changes are the three agents that we are going to study. Temperature increases can be caused by layers of sediments being buried deeper and deeper under the surface of the Earth.
Where does metamorphism most likely occur?
While rocks can be metamorphosed at depth in most areas, the potential for metamorphism is greatest in the roots of mountain ranges where there is a strong likelihood for burial of relatively young sedimentary rock to great depths, as depicted in Figure 7.15.
Different temperaturs and pressures cause new minerals to grow in rocks that have the same composition. The minerals are produced directly related to pressure and temperature conditions. The lower temperature limit for metamorphism is between 200 and 150 degrees. Below these temperatures, changes are part of diagenesis.
How does hot water cause metamorphism in rocks?
Hot water can containing dissolved ions of various elements it contacts. The flow of this water creates unique metamorphic settings in which new materials, the ions, are introduced. This most often results in metallic ore deposits within rock.
How is the composition of a metamorphic rock changed?
Metamorphism is the isochemical process by which rocks are changed by heat or pressure or both. Chemical composition of the parent rock will be the same as the metamorphic rock produced. Rock undergoes slow process of solid-state recrystallisation without melting.
Which is an example of a contact metamorphic rock?
Magma and lava flows can literally bake rocks turning them into other rocks in what is called contact metamorphism. This happens when the molten rock touches another type of rock. A typical example of a contact metamorphic rock is hornfels. Pressure. Like heat, pressure increases as depth into the earth increases.