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Metamorphic Rock
Metamorphic rocks are formed from other types of rocks. The original rock is exposed to conditions such as heat or pressure. Carbon turning to diamonds while under extreme pressure is an example of a metamorphic rock.
653 Questions
Nonfoliated metamorphic rocks?
Nonfoliated metamorphic rocks have a uniform texture without distinct layering. Examples include marble, quartzite, and hornfels. These rocks typically form under high temperature and pressure conditions without the presence of directed stress.
Where is tiger eye metamorphic rock found?
Tiger's Eye, sometimes called crocidolite, is a form of quartz and can be found almost world-wide including Brazil, Russia, Japan, Scotland (UK) and SW Africa.
Nonfoliated metamorphic rock definition?
Nonfoliated metamorphic rocks are formed around igneous intrusions where the temperatures are high but the pressures are relatively low and equal in all directions (confining pressure).
Which rock is an example of a non-foliated metamorphic rock?
Quartzite, marble, and metabasalt are non-foliated metamorphic rocks..................................... i like dots
Why are some metamorphic rocks foliated but others lack folitation?
Nonfoliated metamorphic rocks such as marble and quartzite derived their metamorphism more from heat than from directional pressure. Foliations form at right angles to intense directional pressures. Nonfoliated metamorphic rocks like quartzite and marble are mainly single-mineralic in composition, and would therefore not tend to display layering.
What does metamorphic rocks mean?
== == Rocks that have undergone a change in mineral structure or composition, without melting, through heat and/or pressure are metamorphic rocks. Examples are slate, anthracite, and gneiss.
How does contact (prograde) occur? the changes in mineral assemblage and mineral composition that occur during burial and heating are referred to as prograde metamorphism.
Where does contact (prograde) occur? Contact metamorphism occurs typically around intrusive igneous rocks as a result of the temperature increase caused by the intrusion of magma into cooler country rock. The area surrounding the intrusion where the contact metamorphism effects are present is called the metamorphic aureole. Contact metamorphic rocks are usually known ashornfels. Rocks formed by contact metamorphism may not present signs of strong deformation and are often fine-grained.
Why does contact (prograde) occur? Contact metamorphism occurs typically around intrusive igneous rocks as a result of the temperature increase caused by the intrusion of magma into cooler country rock. The area surrounding the intrusion where the contact metamorphism effects are present is called the metamorphic aureole.[5] Contact metamorphic rocks are usually known ashornfels. Rocks formed by contact metamorphism may not present signs of strong deformation and are often fine-grained.
Contact metamorphism is greater adjacent to the intrusion and dissipates with distance from the contact. The size of the aureole depends on the heat of the intrusion, its size, and the temperature difference with the wall rocks. Dikes generally have small aureoles with minimal metamorphism whereas large ultramafic intrusions can have significantly thick and well-developed contact metamorphism.
The metamorphic grade of an aureole is measured by the peak metamorphic mineral which forms in the aureole. This is usually related to the metamorphic temperatures ofpelitic or alumonisilicate rocks and the minerals they form.The metamorphic grades of aureoles are andalusite hornfels, sillimanite hornfels, pyroxene hornfels.
Magmatic fluids coming from the intrusive rock may also take part in the metamorphic reactions. Extensive addition of magmatic fluids can significantly modify the chemistry of the affected rocks. In this case the metamorphism grades into metasomatism. If the intruded rock is rich in carbonate the result is a skarn. Fluorine-rich magmatic waters which leave a cooling granite may often form greisens within and adjacent to the contact of the granite. Metasomatic altered aureoles can localize the deposition of metallic oreminerals and thus are of economic interest.
Prograde and retrograde metamorphism[edit]
Metamorphism is further divided into prograde and retrograde metamorphism. Prograde metamorphism involves the change of mineral assemblages (paragenesis) with increasing temperature and (usually) pressure conditions. These are solid state dehydration reactions, and involve the loss of volatiles such as water or carbon dioxide. Prograde metamorphism results in rock characteristic of the maximum pressure and temperature experienced. Metamorphic rocks usually do not undergo further change when they are brought back to the surface.
Retrograde metamorphism involves the reconstitution of a rock via revolatisation under decreasing temperatures (and usually pressures), allowing the mineral assemblages formed in prograde metamorphism to revert to those more stable at less extreme conditions. This is a relatively uncommon process, because volatiles must be present.
Garnets with Mn-rich cores and Mn-poorer rims record growth zoning that represents the change from the lower-T conditions at which the garnet core grew to the higher-T conditions at which the garnet rim grew (i.e., prograde metamorphism involving increasing temperature and pressure). Mn is preferentially partitioned into garnet relative to most other common minerals, so Mn is sequestered in early-formed garnet, depleting the local environment of the growing garnet in Mn.
(b) Minerals that show major element growth zoning probably did not experience very high metamorphic temperatures. At high temperature (> 700 C) and sufficient duration, zoning may be homogenized as intracrystalline diffusion becomes more effective at eliminating compositional variation. An unzoned mineral that is typically zoned at low-medium metamorphic grades has either experienced high temperature conditions or was never zoned (owing to a simple reaction history at limited P-T or to growth entirely at high-T).
How is one pathway that could lead to the formation of metamorphic rock?
Rock metamorphosis, or metamorphism, is the change in the crystalline components, chemical composition, or structure of rocks from exposure to intense pressure, heat, or exchange of ions through heated solutions. Metamorphosis of rock usually occurs deep below the Earth's surface, but could also occur from meteor impact, or close contact with a magmatic intrusion.
Metamorphism occurs in rock without melting. Mineral components can recrystallize, form new minerals, and become aligned directionally in physical appearance. Through metamorphosis, one type of rock becomes another type of rock. Sandstone can become quartzite, limestone can become marble, shale can become slate, and so on.
High pressures and temperatures can cause hydrous minerals to change to non-hydrous minerals like garnet. Rounded mineral crystals can become flattened, and minerals that grow in the stressed rock can display a preferred orientation that is perpendicular to the direction of the stress and display a characteristic known as foliation, with distinct banding or platyness. In rocks such as quartzite and limestone, where the minerals are relatively stable along a broad range of temperatures and pressures, the mineral crystals simply become larger. In cases where the metamorphism occurs because of proximity to hydrothermal fluids, a chemical exchange will take place, changing the original composition of the host rock.
Where do we find ultramafic rocks?
Ultramafic rocks are of relatively small extent in the North Cascades, but are geologically significant because they are derived from the Earth's mantle.
How is metamorphic rock is made from sediment?
Metamorphic rocks are formed by rocks sedimentary or igneous that change their form under intense heat and or pressure.
What do bands in a metamorphic rock mean?
The thicker the bands the more intense the heat and pressure conditions were to form the rock.
Metamorphic rocks are transformed existing rock types. Thicker bands in the appearance of a metamorphic rock mean that it was made with more intense heat and under greater amounts of pressure.
Can the mineral grains in a metamorphic rock be flattened?
Yes, and they often are, and appear as foliations.
How does a metamorphic rock form into magma?
Metamorphic rock could become magma by collisions involving an oceanic plates. During subduction,any rock carried on the plate would return to the mantle and melt,forming magma
Why are fossils seldom found in a metamorphic rock?
Cuz dem fossils are da hoes and da pimps dont want his bïtches getting hurt during the contact metamophism (for liability reasons and shît)
What can the texture of metamorphic rock tell us?
In my extensive experience of rock studying, I have concluded through many years of higher learning, including two PHDs and my bachelor's in psychology is that rocks make horrible friends and are in no way a substitute for a lover.
Explain what roles fluids play in rock metamorphism?
It is played as a solumential guidence fluid that flows through the rock to give it its color
What is layering within metamorphic rocks called?
Heat, along with applied pressures, either from depth of burial or from tectonic forces on rock.
How do the properties of a rock change when it becomes a metamorphic rocks?
The parent rock is exposed to varying degrees of pressure and/or heat either from depth of burial, exposure to a plutonic body of intense heat, or from pressures resulting from the collision of tectonic plates. The heat and/or pressure can transform the minerals inside the parent rock to new minerals, cause recrystallization of existing minerals, or reorganize the existing minerals into bands and layers. Exchanges of elements can also occur from hot fluids associated with plutonic intrusions. All of these processes take place without any melting of the parent rock.
Where does heat that changing rocks into metamorphic rock come from?
The heat from the mantle and core.
How does an igneous rock change to metamorphic?
Meta-igneous.
Metamorphism of igneous rocks can form a wide range of metamorphic rocks, depending on the mineralogy of the igneous protolith and the P-T conditions of the metamorphism.
What is an example of a metamorphic rock that is formed when heated under pressure?
Slate is silt changed under pressure.
Can metamorphic rocks from from other metamorphic rocks?
Yes. Most likely it would become a metamorphic rock of higher grade. Slate is a low grade metamorphic rock. With increased heat and pressure it will become schist, a high grade metamorphic rock.
How does a metamorphic rock feel like?
Feeling-wise
Squashed. Cramped. Squeezed. Claustrophobic. Bored.
Texture-wise
Fossils are quite rough in texture, some may feel fragile and crumbly while others could feel smooth or sandy/grainy. It really depends on the rock/soil type that the fossil is encased within.
