In this case the action of the stress results in the recrystallization of the rocks with the formation of new crystals which grow with their length or platy surface at right angles to the direction of maximum compressive stress. The oriented texture produced by platy or columnar minerals is called Schistosity. There are many types of metamorphic rocks.

Igneous rock is formed through the cooling and solidification of magma or lava. Copyright 10. Quartzite, on the other hand, is made of sandstone that has gone through metamorphism, and as the name suggests it primarily contains quartz. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe rock types.
Have you ever heard of quartzite, marble, slate or phyllite? Metamorphic rocks come in three different types: slate, marble and schist. Marble; Limestone, a sedimentary rock changes to form marble.

The result is pulverized, shattered and sometimes melted rock. Near the magma body, high temperature minerals such as garnet may form, whereas farther away low-grade minerals such as chlorite are formed. The specimen shown above is about two inches (five centimeters) across. Amphibolite is a non-foliated metamorphic rock that forms through recrystallization under conditions of high viscosity and directed pressure. This is the rock name to remember when you find a hard, nondescript rock that looks like it could be slate but... 03. Low-grade metamorphism often begins at depth of about 8 km where the temperatures range from 100°C to 200°C. Contact metamorphism is the name given to the changes that take place when magma is injected into the surrounding solid rock (country rock). The most common foliated types of metamorphic rocks are: gneiss, slate, and schist. The minerals have mostly a parallel orientation and accordingly the rocks develop oriented or banded textures. Slate, on the other hand, is a metamorphic rock that is created when shale goes through a deep process of metamorphism.

Your email address will not be published. Regional Metamorphism 4. There are also other types of metamorphic rocks that are less common, each one, however, with an interesting story to tell. Marble is by far the most famous among all types of metamorphic rocks, which occurs when the process of metamorphism ‘meets’ limestone. In part these rocks have the banded or layered appearance of gneiss and yet in other parts of the outcrop, the constituent minerals will have the non-oriented, random, scattered pattern so typical of granite. Low-grade metamorphism takes place at temperatures between about 200 to 320 o C, and relatively low pressure. Usually, it's a hornblende schist like this as... 02. Types of Metamorphism: Regional Associated with Mountain buildings Also known as Dynamothermal - produces both foliated and non-foliated metamorphic rocks. Around the igneous rock that forms from the cooling magma is a metamorphosed zone called a contact metamorphism aureole. Such a pressure is sometimes called confining pressure. During contact metamorphism clay minerals are baked as if placed in a kiln and can generate a very hard fine-grained rock. This magma can be derived from partial melts of existing rocks in either a planet’s mantle or crust. Even a few thousand years back, soapstone was a very common material used to make bowls, cooking slabs and other utensils that served people’s everyday needs; but it was also used by people with a need for artistic expression in order to make ornaments. Regional metamorphism results in the production of highly deformed rocks with slaty cleavage and other manifestations of plastic deformation. Hydrothermal metamorphism is closely associated with igneous activity since it provides the heat required to circulate the ion rich fluids and gas which have intruded into the rock.

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Hornfels is the name applied to the wide variety of hard, non-foliated metamorphic rocks formed during contact metamorphism. The last two types of metamorphic rocks in this category are hornfels and amphibolite. This type of metamorphism takes place when the very hot magma moves up through the crystal rocks and brings with it high levels of heat. Types, Geology, Rocks, Metamorphism, Types of Metamorphism. Rocks are mineral aggregates with a combination of properties of all the mineral traces. Moving on to non-foliating types of metamorphic rocks, one comes across hornfels, amphibolite, soapstones, quartzite, and of course marble.
Metamorphic grade is a general term for describing the relative temperature and pressure conditions under which metamorphic rocks form.

Besides an immense quantity of heat liberated around an igneous intrusion, huge amounts of gas and fluids are also freed. Hornfells can be created only if a rock is so close to a heat source that it becomes ‘baked’, as we say in urban language. Content Guidelines 2. Often these two types of rocks will alternate with each other in a single outcrop. Foliated Metamorphic Rocks Olivine is an unstable mineral chemically and in rocks where it is abundant as in dunite the rock is altered readily from gabbro to serpentine when it is attacked by chemically active hot waters coming from an igneous intrusion. Thus hydrothermal metamorphism often occurs along with contact metamorphism in regions where large plutons are emplaced. Sedimentation may also occur as minerals precipitate from water solution or shells of aquatic creatures settle out of suspension. Burial Metamorphism 5.