What are metamorphic rocks? Formation of metamorphic rock?

len Alfred Ajibola - Thu, 24th January, 2019 @ 6:28 PM

Topics in Geography

Environmental geography explained with its branches Igneous rock explained with its types and textures Characteristics of Igneous Rock What are Sedimentary Rocks? Formation and Types of Sedimentary Rock Characteristics of Sedimentary Rock Types and Characteristics of Metamorphic Rock Physical geography explained with its branches Geography Scheme of Work, SS1, First Term Geography Scheme of Work, SS1, Second Term Geography Scheme of Work, SS1, Third Term Classification and types of planets with their characteristics Planets of the solar system explained with their characteristics Functions of the Atmosphere Layers of the Atmosphere Solar System in Geography Composition of the Atmosphere Human geography explained with its branches What are metamorphic rocks? Formation of metamorphic rock?

Academic Questions in Geography

Please click here to see all Questions and Answers

Sandstone is an example of _____ ​​​​​​.

  • A. Sandy soil

  • B. Loamy soil

  • C. Clay soil

  • D. Igneous rock

  • E. Sedimentary rock 

  • F. Metamorphic rock

Which of the following isn't an example of metamorphic rock?

  • A. Schist

  • B. Quartzite

  • C. Gabbro

  • D. Marble

  • E. Slate

  • F. Serpentinite

Which of the following statements is false concerning metamorphic rock?

  • A. The are less dense than igneous and sedimentary rocks

  • B. They can be foliated or non foliated

  • C. They are crystalline in nature

  • D. They have a more coarse texture than their protolith

  • E. They may be formed from an older metamorphic rock

  • F. They are characterized with precious metals and stones

Earth's distance from the sun is approximately _____ million kilometers.

  • A. 147

  • B. 85

  • C. 40

  • D. 220

  • E. 309

  • F. 400

Which of the following is not a branch of physical geography?

  • A. Economic Geography

  • B. Religious Geography

  • C. Social Geography

  • D. Resource Geography

  • E. Settlement Geography

  • F. Industrial Geography

Water resource geography is a branch under physiography.

  • A. True

  • B. False

With regards to ozone, which of the following is incorrect?

  • A. Ozone is a triatomic molecule

  • B. Ozone layer aids in preventing excess ultraviolet radiation from reaching the earth

  • C. Ozone is a natural greenhouses gas

  • D. Ozone comprises of oxygen molecules only

  • E. Ozone layer brings about a global warming on earth

  • F. Ozone is present in the stratosphere

The atmosphere makes the followings possible on earth except _____.

  • A. Photosynthesis

  • B. Respiration

  • C. Rain

  • D. Ultraviolet rays

  • E. Global communication

  • F. Weather

Metamorphic Rock:

We have 3 types or classes of rock based on how they are formed. These are:

  1. Igneous Rock

  2. Sedimentary Rock

  3. Metamorphic Rock

The term 'metamorphic' is derived from the word metamorphose which means 'to change form'. In this regard, meta means 'change' while morph means 'form', thus giving credence to the name 'metamorphic'.

Metamorphic rocks make up about 12% of the earth crust and can also be formed beneath the earth surface. Their formation requires the transformation of an existing rock or original rock called protolith. The protolith may be an igneous rock, a sedimentary rock or another older metamorphic rock.

Metamorphic rocks originate from igneous, sedimentary or an older metamorphic rock that had altered their form or recrystallized through visible changes in their physical atmosphere. In short, metamorphic rock is a rock formed from another rock.

Examples of metamorphic rocks include schist (a converted basalt), quartzite (a compressed sandstone), and marble (a compressed limestone or dolomite), gneiss and slate. These are shown in the image below:

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Formation of Metamorphic Rock:

Metamorphic rocks are derived from a variety of changes occuring within its protolith. These resultant changes are due to intense heat and pressure, chemical activity and hot mineral-rich fluids present inside the earth crust. The process of igneous and sedimentary rocks changing into metamorphic rock is termed metamorphism. In simple terms, the transformation of a protolith may be physical or chemical. Importantly, both forms of transformation require great heat and pressure.

You can read on the functions of the atmosphere here.

Contact metamorphism results when great heat and pressure from inside the earth slightly melts a rock. It is important to state that the process of metamorphism does not melt the parent rocks, rather it changes them into more compact and denser rocks. Below are the processes that results into metamorphism:

  • There is magma intrusions and high tectonic movements from earth's movements, which consequently causes movement and shifting of the pre-existing igneous rocks.

  • Resulting from earth's tectonic movements is an influx of heat and high pressure from the rocks inside the earth (earth crust). This brings about changes in the rock's mineralogy, chemical composition, and texture.

  • The heat energy ranges between 150oC and 795oC. This degree of heat may be sufficient to break and reform the rock's chemical composition. Meanwhile, recall that this heat is a result of magma and friction heating along the fault lines.

  • Pressure coming from the overlying rocks further increases the transformation process.

  • The rearrangement of fluids and mineral components creates new minerals within the rock. However, the rocks does not melt, rather the grouping of minerals rearrange the elements in line with the original minerals thus forming new mineral compositions.

  • The newly formed minerals become steady at the new temperature and pressure.

  • The chemical composition and texture changes result from an extreme temperature gradients in melted magma and the surrounding rocks.

  • The aforementioned changes transform the crystal composition of the rock alongside its size.

You can read on the solar system here.

After all the above processes had occur, the original rocks becomes transformed into metamorphic rocks. In this regard, the following points are noteworthy:

  • Contact or thermal metamorphic rocks are produced as a result of intrusions and direct lava or magma heating.

  • Regional metamorphic rocks are produced from high-temperature changes and distributed pressure prompted by tectonic movements.

Please read on physical and environmental geography here.

Although most metamorphic rocks are formed deep within the earth's crust, some may become exposed on earth's surface due to erosion of the rock and soil, alongside the geologic uplift above them.

Meanwhile, when metamorphic rocks are exposed to the surface of the earth, the process of weathering breaks them down into sediments. Compression of the sediment results into the formation of sedimentary rocks.

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Amazing facts in Geography

Pepto Bismol-colored Lake Hillier is a pink colored lake present in Australia

Pepto Bismol-colored Lake Hillier - Len Academy

Mount Everest is the highest point on earth with a height of 8,849 meters (29,032 feet). It is located between Nepal and Tibet, an autonomous region of China.

Mountain Everest is a symbol of relationship between Nepal and Tibet, and was named in the nineteenth century after George Everest, a former Surveyor General of India

A day on planet venus is longer than a year. This is so because it takes venus 243 'earth days' to spin round its axis (rotation), but takes 225 'earth days' to go around the sun (revolution).

In geography, understand that a day is reached when the planet makes a full spin or rotation round it's axis. However, a year is reached when a planet revolves fully around the sun

The Four Corners is a location in the United States of Ameria where one can stand in four states simultaneously (at the same time). The states are: Utah, Colorado, Arizona and New Mexico.

On the Four Corners, a person stands on the southwestern corner of Colorado, southeastern corner of Utah, northeastern corner of Arizona, and northwestern corner of New Mexico at once.

The longest street in the world is Yonge street in Toronto Canada. It has a length of 1,895,807.232 meters or 1,178 miles

With regards to size, the sun is so big when compared to earth. In fact, a million earth would fit inside of it

Pumice - Len Academy

Pumice is a rock that floats on water

There are more stars in space than there are grains of sand on a beach

Africa on the globe hemispheres - Len Academy

Africa is the only continent with land in all four hemispheres of the globe

Venus is the only planet that spins in a clockwise direction


The interface forming the boundary between two atmospheric layers are always named with a 'pause' at its end; for instance;

  • Tropopause: This is the interface or boundary between the troposphere and stratosphere.

  • Stratopause: Interface between the stratosphere and mesosphere.

  • Mesopause: Interface between the mesosphere and ionosphere.

  • Ionopause: Interface between the ionosphere and thermosphere.

The atmosphere surrounding the earth is layered. Each layer has its own characteristics although the boundaries between them are not clearly defined.

The image below shows the different layers of the atmosphere:

Layers of the Atmosphere - Len Academy

Please read more on the layers of the atmosphere here.

The Solar System - Len Academy

The average distance between the earth and the sun is about 149.6 million kilometers. It will take the earth 365 one-quarter days (or 1 year) to make a complete orbit (or revolve) round the sun. This process is termed the revolution of the earth.

The revolution of the earth is responsible for the seasonal changes we experience here (on earth). In Nigeria and Africa at large, these are the rainy and dry seasons. In Europe, these are spring, summer, autumn and winter seasons. Similarly, the United States of America have got the spring, summer, fall and winter seasons respectively.

The Solar System - Len Academy

The solar system is defined as a system comprising the sun, all the planets that revolve around it including their moons, the comets, meteoroids, asteroids and interplanetary medium.

In summary, the solar system comprises of the followings:

  • Sun

  • Stars

  • Planets

  • Moons or Satellites

  • Comets

  • Meteoroids

  • Asteroids

  • Interplanetary Medium (IPM)

Please read more on the solar system here

The atmosphere consists of gases that surround the entire surface of the spherical shaped earth. The compositions of these gases are as follows:

Composition of the Atmosphere -Len Academy

  • Nitrogen (N2): 78.09%
  • Oxygen (O2): 20.95%
  • Argon (Ar): 0.93%
  • Carbon(IV)oxide (CO2): 0.036%
  • Neon (Ne): 0.002%
  • Krypto (Kr): 0.001%
  • Helium (He): 0.0005%
  • Xenon (Xe): 0.00009%
  • Hydrogen (H2): 0.00005%
  • Water Vapour: Variable

All of these gases (listed above) make up the atmosphere and are generally called air.

Please read more on the atmosphere and it's composition here