Where do metamorphic rocks originate? How are they formed?

What are the two categories of metamorphic rocks? What are the distinguishing characteristics between the two categories of rocks?

Metamorphic gets their name from change which is called "meta" and "morph" the proper name for the metamorphic rock is recrystallized rock. Now, of course, any rock can become a metamorphic rock as long as it is moved to an environmental condition. This allows the minerals that make the rock become unstable and out of the equilibrium due to the environmental conditions.
Metamorphic rocks are developed from; first of all there are many varieties of textures it depends on if the metamorphic rock was developed from erosion, a volcano or the movement of the rocks on the surface.
Magma is the start of the whole cycle of rocks. When the magma becomes solid from cooling off, then magma forms the igneous rocks. Then from the igneous rock the sedimentary Rocks is then developed from the minerals grain from erosion being weathered off which are then carried by water, ice and wind. This then goes to the bottom of the ocean or sea etc. which then eventually becomes metamorphic.

Foliation is planar arrangement of textural features in a metamorphic rock, which give the rock a layered or finely banded appearance.

The two types of metamorphic rocks are foliated metamorphic rocks and non foliated metamorphic rocks. Some examples of foliated metamorphic rocks are slate, schist, and gneiss. Some examples of non foliated rocks are marble and quartz. Foliated metamorphic rocks have layered or banded appearance that is produced by exposure to heat and directed pressure. Non foliated metamorphic rocks do not have a layered or banded appearance.

Your last two paragraphs are great!

I don't think you understand what you wrote in your first paragraph.

This site explains briefly how metamorphic rocks were formed.

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Your first paragraph has a lot of extra information in it -- but you didn't give the basics of how metamorphic rocks are formed -- heat and pressure.

Metamorphic rocks originate from pre-existing rocks that undergo changes in temperature, pressure, and chemical composition. These changes occur deep within the Earth's crust, usually at depths where the rocks experience high temperatures and pressure. There are two main processes through which metamorphic rocks are formed: contact metamorphism and regional metamorphism.

1. Contact Metamorphism: This process occurs when rocks come into contact with magma or molten rock. The heat from the magma causes the surrounding rock to heat up and undergo changes. The temperature increase leads to the recrystallization and growth of new minerals within the rock, resulting in the formation of metamorphic rocks. The original rock's appearance may change, but the texture remains non-foliated.

2. Regional Metamorphism: This process occurs over large areas and is associated with the tectonic forces that shape the Earth's crust. It typically happens in regions where mountains are forming or where tectonic plates are colliding or sliding past each other. The intense pressure and temperature deep within the Earth cause the minerals in the rocks to recrystallize and rearrange. The original rock's texture can change, resulting in the formation of either foliated or non-foliated metamorphic rocks.

Now, coming to the two categories of metamorphic rocks:

1. Foliated Metamorphic Rocks: These rocks have a layered or banded appearance due to the alignment of minerals under directed pressure. The minerals within the rock flatten and align parallel to each other, creating a distinct texture. Examples of foliated metamorphic rocks include slate, schist, and gneiss.

2. Non-Foliated Metamorphic Rocks: These rocks do not have a layered or banded appearance. They typically result from contact metamorphism, where the heat causes the minerals to recrystallize without significant deformation or flattening. Examples of non-foliated metamorphic rocks include marble and quartzite.

In summary, metamorphic rocks originate from pre-existing rocks that undergo changes in temperature, pressure, and chemical composition. They can be formed through contact metamorphism or regional metamorphism. The two categories of metamorphic rocks are foliated and non-foliated, distinguished by the presence or absence of a layered or banded appearance.