Characteristics of Igneous Rock

len Alfred Ajibola - 19th June, 2022 @ 04:02 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

Characteristics of Igneous Rock:

Igneous rocks can be defined as rocks formed from the cooling and solidification of molten substances called magma or lava either below the earth (crust) or on the surface of the earth. Magma can be derived from melting of existing rocks on the earth crust.

The solidification of magma into igneous rock may be below the earth's surface (intrusive) or on the earth's surface (extrusive), thus giving rise to the two types of igneous rock.

Please read the introduction to igneous rock and its types here.

Examples of igneous rocks include basalt, granite and gabbro. They are shown in the image below:

Len Academy

Please read on metamorphic rock and its formation here.

Below are the characteristics or features of igneous rocks:

  1. Igneous rocks are formed from the cooling and solidification of magma or lava either below the earth or on its surface.

  2. About 95% of igneous rocks are present below the earth (earth crust) while 15% are found on the surface of the earth.
    Please read the introduction to sedimentary rock here.

  3. They have variations in texture, that is: size, shape and crystal arrangement. This is dependent on the rate and place of cooling or solidification of magmas.

  4. Igneous rocks have no form of fossil deposits within them as a result of massive heat they produce during eruption. This massive heat evolved alongside its formation eventually destroy the remains of plants or animals (fossils).

  5. Igneous rocks are generally hard rocks permitting very little or no water percolation into it. However, understand that igneous rock may become soft from exposure to environmental conditions over a long period of time. An example is basalt.
    Please read on the types and characteristics of metamorphic rock here.

  6. Igneous rocks are granular (or crystalline) and hard in nature.

  7. Unlike sedimentary rocks, igneous rocks have no strata. Meanwhile, understand that when the flow of lava occur in several phases, different layers of lavas are deposited with their solidification stacking up upon one another. These are called layers of lavas and not strata.
    Please read on the characteristics of sedimentary rock here.

  8. Since igneous rocks are typically associated with volcanic activities, they are therefore referred to volcanic rocks. In fact, they are always found in volcanic zones.

  9. The number of joints in igneous rocks increases in the upward direction. However, these joints often contain minerals which increases the hardness of the rock, thus making them resistant to weathering.
    You can read on the solar system here.

  10. The texture of igneous rocks can be fine grained, coarse grained or glassy depending on the rate of magma solidification. In this regard, if the magma cools and solidifies at a very slow rate inside the earth, coarse grained rock will be formed. Conversely, if the magma solidifies as soon as it reaches the earth, finely grained crystals will be formed.

  11. They typically do not react with acids.
    Please read on the physical and chemical properties of acids here.

  12. Igneous rocks are less affected by chemical weathering since water barely penetrates the rock. However, basalt is an igneous rock that is easily weathered through frequent contact with water. With regards to coarse grained igneous rocks, they are affected by physical (or mechanical) weathering.

  13. Most igneous rocks contain various mineral deposits which occurs in patches with varying sizes.

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On mountain everest for instance, mountain climbers will need to carry oxygen canisters because lesser amount of oxygen is present on this mountain.

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The image below shows the different layers of the atmosphere:

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