RBSE Solutions for Class 11 Physical Geography Chapter 6 Rocks

Rajasthan Board RBSE Class 11 Physical Geography Chapter 6 Rocks

RBSE Class 11 Physical Geography Chapter 6 Text Book Questions

RBSE Class 11 Physical Geography Chapter 6 Multiple Choice Questions

Question 1.
Which is the igneous rock out of the following?
(a) Gneiss
(b) Marble
(c) Diamond
(d) Slate
Answer:
(d) Slate

Question 2.
The original rock is:
(a) Igneous
(b) Layered
(c) Sedimentary
(d) Metamorphic
Answer:
(a) Igneous

Question 3.
The rocks in which fossils are not found are:
(a) Layered
(b) Secondary
(c) Igneous
(d) Metamorphic
Answer:
(c) Igneous

Question 4.
Which is the metamorphic rock out of the following?
(a) Granite
(b) Marble
(c) Basalt
(d) None of these
Answer:
(b) Marble

Question 5.
Which is the sedimentary rock out of the following?
(a) Granite
(b) Limestone
(c) Basalt
(d) Marble
Answer:
(d) Marble

RBSE Class 11 Physical Geography Chapter 6 Very Short Answer Type Questions

Question 1.
Give two examples of the igneous rocks.
Answer:
Granite and Gabbro are the two main examples of the igneous rocks.

Question 2.
What is a rock?
Answer:
All the substances that have formed the earth’s crust, whether they are hard as granite or soft as clay are called rocks.

Question 3.
Mention the metamorphosed form of any two sedimentary rocks.
Answer:
Limestone is a sedimentary rock that metamorphosed into marble and coal is a sedimentary rocks which metamorphosed into graphite and diamond.

Question 4.
Define rock.
Answer:
In simple language, the word rock is used for any hard object. According to geological perspective, all the substances that have formed the earth’s crust are called rocks.

Question 5.
Define the sedimentary rocks.
Answer:
By the process of denudation, the rocks break down and get accumulated at the same place or elsewhere. The rocks formed by the accumulation of layers over the layers on the fossils of living – organisms, vegetation and rocks – flour obtained from different rocks are called sedimentary rocks.

RBSE Class 11 Physical Geography Chapter 6 Short Answer Type Questions

Question 1.
Mention the features of igneous rocks.
Answer:
The following are the features of igneous rocks:

1. There is a lack of layers in igneous rocks.
2. These rocks are non-porous.
3. These rocks are crystallized.
4. Fossils are not found in these rocks.
5. These rocks are extremely hard.
6. The effect of physical weathering on these rocks is greater in amount compared to chemical weathering.
7. Metallic minerals are found in these rocks.

Question 2.
Mention the features of the sedimentary rocks.
Answer:
The following are the features of sedimentary rocks:

1. Many layers are found in these rocks.
2. These rocks are porous.
3. Fossils are found between the layers of these rocks.
4. The erosion of these rocks occurs at relatively faster speed.
5. These rocks are generally soft.

Question 3.
Mention the features of the metamorphic rocks.
Answer:
The following are the features of metamorphic rocks:

1. These are the secondary rocks because they are formed by the transformation or change in the forms of other rocks.
2. These rocks are more organized and hard compared to the original rocks.
3. These rocks contain metallic minerals in abundance, thus, these rocks are economically important.
4. These rocks are non – porous.

Question 4.
Mention the names of metamorphic rocks that are made up of sedimentary rocks.
Answer:
The following are the metamorphic rocks that are made up of sedimentary rocks:

Sedimentary Rock	Metamorphic Rock
Sandstone	Quartzite
Limestone	Marble
Shale	Slate
Coal	Graphite and Diamond

Question 5.
Mention the names of metamorphic rocks that are made up of igneous rocks.
Answer:
The following are the metamorphic rocks that are made up of igneous rocks:

Igneous Rock	Metamorphic Rock
Granite	Gneiss
Basalt	Amphibolite
Gabbro	Serpentine

RBSE Class 11 Physical Geography Chapter 6 Essay Type Questions

Question 1.
Classify the rocks and give a detailed description of the metamorphic rocks.
Answer:
The rocks found on the earth’s surface are being divided into different parts on the basis of their origin, duration and composition. This classification of rocks is being presented in the following table:

Description of Metamorphic Rocks

Definition of Metamorphic Rocks:
The different types of rocks made by the basic changes in the properties and structure of the original rocks without their disintegration and dissociation are called Metamorphic Rocks.

Cause of Metamorphism:
Metamorphism of the original rocks is due to the effect of mainly water, heat and pressure.

Features of Metamorphic Rocks:
Metamorphic rocks are the secondary rocks. These are harder than the original rocks. These rocks are non – porous. Metallic minerals are found in abundance in these rocks.

Classification of metamorphism of the Metamorphic Rocks:
Metamorphism of the Metamorphic Rocks are classified into four parts: Thermal Metamorphism, Regional Metamorphism, Hydro Metamorphism and Thermo – Hydro Metamorphism.

Thermal Metamorphism occurs due to extreme high heat. Regional Metamorphism occurs due to compression and heat. Hydro Metamorphism occurs due to action water on chemical materials. Thermo – Hydro Metamorphism occurs due to action of water vapor and pressure.

Classification of Metamorphic Rocks:
On the basis of the original rocks, due to whose metamorphism the Metamorphic Rocks are made, the rocks are being classified into the following parts:

Original Rock	Metamorphic Rock
Granite	Gneiss
Basalt	Amphibolite
Gabbro	Serpentine
Sandstone	Quartzite
Limestone	Marble
Shale	Slate
Coal	Graphite and Diamond

Re – metamorphism of few Metamorphic Rocks like:

Metamorphic Rock	Re – metamorphic Rock
Slate	Schist
Schist	Phylite

Question 2.
Classify the igneous rocks and give a detailed description of them.
Answer:
Igneous rocks are the first to be formed, thus, they are also called Primary Rocks. The lack of fossils is found in these rocks. On the basis of the composition of minerals, texture, formation of particles, shape and formation place of the igneous rocks, they are classified as follows:

(I) Classification of Igneous Rocks on the basis of formation – place:

(i) Intrusive Igneous Rocks:
Rocks which are formed due to the accumulation of magma beneath the earth’s surface are called Intrusive Igneous Rocks. These rocks are further classified into two parts:

1. Plutonic Rocks
2. Hypabyssal

1. Plutonic Rocks:
These rocks are formed when the magma cooled down and solidified at too much depth beneath the earth’s surface. Granules of big size are found in these rocks. The main example is Granite.

2. Hypabyssal Rocks:
Rocks formed when the magma is solidified in the cracks at some depth beneath the earth’s surface are called Hypabyssal Rocks. These rocks are presented with the help of the following fig.

(ii) Extrusive Igneous Rocks:
These type of rocks are formed when the lava erupted above the earth’s surface cooled down and solidified. The size of granules is small in these rocks.

(II) Classification of Igneous Rocks on the basis of chemical composition :

1. Acidic Rock:
Rocks in which the amount of silica is more than 65% are included in the category of Acidic Rocks.

2. Basic Rock:
Rocks in which the amount of silica is in between 45% to 55% are included in the category of Basic Rocks.

3. Intermediate Rock:
Rocks in which the amount of silica is in between Acidic and Basic Rocks.

4. Ultra – Basic Rock:
The amount of silica is less than 45% in these rocks.

Question 3.
Classify the Sedimentary Rocks and give a detailed description of them.
Answer:
Sedimentary rocks were formed after the igneous rocks. Sedimentary rocks are formed by the accumulation of many types of materials and sediments. These rocks are formed by the accumulation of layers over the layers on the fossils of living – organism vegetation and rocks-flour of different rocks. These rocks are classified into the following parts:

Classification of Sedimentary Rocks:
Sedimentary rocks are formed by many types of materials and sediments. These rocks are classified on the following basis:

1. On the basis of the sediments used in formation.
2. On the basis of the resources used in formation.

1. On the basis of the sediments used in formation:
In this classification of rocks, the rocks are classified into clastic rocks, Organically Formed Rocks and Chemically Formed Rocks.

(a) Clastic Rocks:
Rocks – flour obtained by the processes of weathering and erosion gets accumulated at a place in the form of layers. Over the passage of time, this accumulation organizes and takes the form of sedimentary rocks.
Examples: Sandstone, Clay, etc.

(b) Organically Formed Rocks:
Rocks which are formed by the fossils of living – organisms and vegetation are included in this category. This includes lime – oriented and carbon – oriented rocks.
Examples: Dolomite and Coal – oriented rocks.

(c) Chemically Formed Rocks:
Rocks which are formed when various chemical substances dissolved and solidified are included in this category.
Examples: Alabaster, Gypsum, Sart rock, etc.

2. On the basis of the resources used in formation:
On this basis, the sedimentary rocks are classified into three parts: Aqueous Rocks, Aeolian Rocks and Glacial Rocks.

(a) Aqueous Rocks:
These rocks are formed by the deposition of sediments in aquatic parts. Like-river rock, sea rock, etc.

(b) Aeolian Rocks:
These rocks are formed by the transportation and deposition of particles by wind; e.g. Loess

(c) Glacial Rocks:
Rocks which are formed by the transportation and deposition of pebbles and boulders by the glaciers.

RBSE Class 11 Physical Geography Chapter 6 Other Important Questions

RBSE Class 11 Physical Geography Chapter 6 Multiple Choice Questions

Question 1.
Which rocks are dominant on the topmost part of the earth?
(a) Igneous
(b) Sedimentary
(c) Metamorphic
(d) None of these
Answer:
(a) Igneous

Question 2.
Which type of rock is Granite?
(a) Plutonic Rock
(b) Hypabyssal Rock
(c) Basic Rock
(d) Ultra Basic Rock
Answer:
(a) Plutonic Rock

Question 3.
Which type of rock is Basalt?
(a) Acidic Rock
(b) Basic Rock
(c) Intermediate Rock
(d) Ultra – Basic Rock
Answer:
(b) Basic Rock

Question 4.
Which rock is found on the maximum part of the total earth’s surface?
(a) Igneous
(b) Sedimentary
(c) Metamorphic
(d) None of these
Answer:
(b) Sedimentary

Question 5.
Which is the lime – oriented rock out of the following?
(a) Granite
(b) Loess
(c) Dolomite
(d) Schist
Answer:
(c) Dolomite

Question 6.
The rock formed by the metamorphism of Gabbro is:
(a) Gneiss
(b) Slate
(c) Schist
(d) serpentine
Answer:
(d) serpentine

Question 7.
Diamond is formed by the metamorphism of:
(a) Basalt
(b) Sandstone
(c) Coal
(d) Granite
Answer:
(c) Coal

Question 8.
Which rock is formed by the metamorphism of limestone?
(a) Gneiss
(b) Amphibolite
(c) Quartzite
(d) Marble
Answer:
(d) Marble

Matching Type Questions

Question 1.
Match Column A with Column B:

Column A, (Type of Rock)	Column B (Process of Formation)
(i) Granite	(a) Lime – oriented Rock
(ii) Lapolith	(b) Glacial Rock
(iii) Gabbro	(c) Plutonic Rock
(iv) Peridotite	(d) Clastic Rock
(v) Clay	(e) Hypabyssal Rock
(vi) Dolomite	(f) Ultra – Basic Rock
(vii) Glacier	(g) Basic Rock

Answers:

1. (c)
2. (e)
3. (g)
4. (f)
5. (d)
6. (a)
7. (b)

Question 2.
Match Column A with Column B:

Column A (Original Rock)	Column B (Metamorphic Rock)
(i) Basalt	(a) Quartzite
(ii) Shale	(b) Phyllite
(iii) Sandstone	(c) Graphite
(iv) Schist	(d) Amphibolite
(v) Coal	(e) Slate

Answers:

1. (d)
2. (e)
3. (a)
4. (b)
5. (c)

RBSE Class 11 Physical Geography Chapter 6 Very Short Answer Type Questions

Question 1.
What is the upper layer of Earth called?
Answer:
The upper layer of Earth is called the Crust (earth surface).

Question 2.
How many types of rocks are found?
Answer:
Three types of rocks are found on the earth’s surface – igneous rocks, sedimentary rocks and metamorphic rocks.

Question 3.
What is Igneous Rock?
Answer:
Rocks formed when the hot and fluid magma and lava cooled down and solidified at the time of formation of the earth are called Igneous Rocks. These are also called Primary Rocks.

Question 4.
On which basis are igneous rocks classified?
Answer:
Igneous rocks are classified on the basis of the formation-place and chemical composition.

Question 5.
What is Intrusive Igneous Rock?
Answer:
Rocks which are formed when magma is solidified beneath the earth’s surface are called Intrusive Igneous Rocks.

Question 6.
What is Plutonic Rock?
Answer:
Rocks which are formed when the magma cooled down and solidified at considerable depth beneath the earth’s surface are called Plutonic Rocks.

Question 7.
What does Hypabyssal Rock mean?
Answer:
Rocks which are formed when the magma solidified in the cracks at some depth beneath the earth’s surface are called Hypabyssal Rocks. These are small – sized rocks.

Question 8.
What does Acidic Rock mean?
Answer:
Rocks in which the amount of silica is more than 65% are called Acidic Rocks. These are generally hard and strong rocks.

Question 9.
What does the term Basic Rock mean?
Answer:
Rocks in which the amount of silica is in between 45% to 55% are called Basic Rocks.

Question 10.
On which basis are the sedimentary rocks classified?
Answer:
Sedimentary rocks are classified mainly on the basis of the sediments used and the resources used in their formation.

Question 11.
Into which categories are the sedimentary rocks classified according to the sediments used?
Answer:
According to the sediments used, the sedimentary rocks are classified into Clastic Rocks, Organically Formed Rocks and Chemically Formed Rocks.

Question 12.
Into which parts are the sedimentary rocks classified according to the resources used in formation?
Answer:
According to the resources used in formation, the sedimentary rocks are classified into Aqueous Rock, Aeolian Rock and Glacial Rock.

Question 13.
What is Lime – oriented Rock?
Answer:
Rocks which are formed by lime dominated living organisms are called Lime – oriented Rocks.

Question 14.
What are Aqueous Rocks?
Answer:
Rocks which are formed by the deposition of sediments in aquatic parts are called Aqueous Rocks.

Question 15.
What does the term Aeolian Rock mean?
Answer:
Rocks which are formed by the transportation and deposition of the particles by wind are called Aeolian Rocks.

Question 16.
What is Thermal Metamorphism?
Answer:
The process of change in the form of the igneous and sedimentary rocks and rebuilding of granules in their minerals by the effect of extreme heat is called Thermal Metamorphism.

Question 17.
What does the term Hydro Metamorphism mean?
Answer:
The process of change in the minerals of rock in the form of a solution by the mixing of chemical materials with water is called that Hydro Metamorphism.

Question 18.
What is Thermo – Hydro Metamorphism?
Answer:
When there is hot water on the rocks, then the changes that occur in the rocks due to pressure of water – vapor is called that Thermo – Hydro Metamorphism.

Question 19.
Which are the Re – Metamorphic Rocks?
Answer:
Slate re – metamorphosed into Schist, and Schist re – metamorphosed into Phyllite.

RBSE Class 11 Physical Geography Chapter 6 Short Answer Type Questions (SA-I)

Question 1.
Why is the outer layer of earth the important?
Answer:
The outer layer of earth is very important because many types of valuable elements are found in this layer. Oxygen, silicon, aluminium, iron, calcium, sodium, potassium, magnesium, phosphorus, sulphur, etc. are found in this layer. These elements are not found separately, but generally they combine with other elements to create different substances. Minerals are the most important in these substances.

Question 2.
Why are igneous rocks called the primary rocks?
Answer:
Rocks which are formed when the hot and fluid magma and lava cooled down and solidified at the time of formation of the earth are called the Igneous Rocks. These rocks are the first to be formed, thus, they are also called the Primary Rocks. After these rocks only, other rocks have been formed.

Question 3.
What are the differences between Acidic Rocks and Basic Rocks?
Answer:
The following differences are found between Acid Rocks and Basic Rocks:

Acid Rock	Basic Rocks
1. The amount of silica is found more in these rocks.	1. The amount of silica is found less in these rocks.
2. More than 65% of silica is found in these rocks.	2. Less than 55% of silica is found in these rocks.
3. These are hard and strong rocks.	3. These rocks are less hard and less strong as compared to Acidic Rocks.

Question 4.
Explain the meaning of Phacolith and Lapolith.
Answer:
The difference between Phacolith and Lapolith is as follows:

1. Phacolith:
The magma solidified in the syncline of folded mountains at the time of volcanic eruption. The shape of this type of igneous rock is called Phacolith.

2. Lapolith:
Lapolith is a word made of the German word ‘Lopass’, whose meaning is a shallow basin. In this type of topography, magma solidified in the shape of a saucer. This type of shape is called Lapolith.

Question 5.
Explain the difference between Sills and Dykes.
Answer:
1. Sills:
When metamorphism or accumulation of magma found in the internal part of earth occurs horizontally between sedimentary rocks, then this accumulation of solidified magma in the form of layers is called Sills. This accumulation of sills is found in thick form.

2. Dykes:
In the internal part of earth, the vertical accumulation of magma in the rocks or in their walls is called Dykes. This accumulation of Dykes is found in long and thin form. This is an internal form of igneous rock like a wall. The organization of Dykes is somewhere hard and somewhere soft.

Question 6.
Explain the process responsible for the formation of sedimentary rocks.
Answer:
With the earth coming into existence, the powers of denudation started on it. In this, rocks break down and get accumulated at the same place or elsewhere through weathering and erosion. The rocks formed by the accumulation of layers over the layers on the fossils of living – organisms, vegetation and rocks – flour obtained from different rocks, came to be known as Sedimentary Rocks. These rocks are formed by many types of substances and sediments. Many processes take place in their formation.

Question 7.
Explain the origin of Metamorphic Rocks.
Answer:
Different types of rocks formed by the basic changes in the properties and structure of the original rocks without their disintegration and dissociation are called Metamorphic Rocks. These original rocks can be igneous, sedimentary or even metamorphic. This metamorphism is due to the effect of water, heat and pressure.

The igneous and sedimentary rocks are metamorphosed, and few metamorphic rocks are also re – metamorphosed. In this metamorphism, in addition to the complete change in the shape of rocks, the structure of minerals also changes. In this, new shape of old minerals can be formed, new minerals can be formed, rocks can take another shape, granular size of rocks can be changed.

RBSE Class 11 Physical Geography Chapter 6 Short Answer Type Questions (SA-II)

Question 1.
Explain the importance of igneous rocks.
Answer:
Igneous rocks are the first to be formed on the earth’s surface, due to which, they are significantly important. The importance of these rocks is presented through the following points:

1. Abundant minerals are found in these rocks. Minerals like gold, silver, zinc, copper, sulphur, magnesite etc. are found in these rocks.
2. These rocks are the primary rocks, thus, other rocks have been formed from them.
3. The processes of weathering and erosion have their effect on these rocks. Due to this reason, the black soil has been formed from them.
4. The stones/rocks obtained from these rocks are useful for the work of constructing buildings.
5. Due to the fertile soil produced by these rocks, they are beneficial from the agricultural perspective.
6. The surface water filters through these rocks and goes inside. Thus, these rocks are important in enhancing groundwater purity.

Question 2.
How do the Plutonic Rocks differ from the Hypabyssal Rocks. Explain.
Answer:
The following differences are found between the Plutonic and the Hypabyssal Rocks:

Plutonic Rocks	Hypabyssal Rocks
1. These rocks are formed at considerable depth inside the earth.	1. These rocks are formed at some depth inside the earth.
2. These rocks are formed when the magma solidifies inside the earth.	2. These rocks are formed when the magma solidifies in the cracks of rocks.
3. The slow process of cooling down of the magma mainly contributes in the formation of these rocks.	3. The formation of these rocks is the result of the quicker cooling down of the magma and less time involved.
4. The Granules in this type of rocks are big in size.	4. The Granules in this type of rocks are small in size.
5. This type of rocks are usually hard.	5. Little softness is found in this type of rocks.

Question 3.
Explain the nature of Clastic Rocks and Chemically Formed Rocks.
Answer:
Clastic Rocks:
Rock – flour obtained by the processes of weathering and erosion gets accumulated at a place in the form of layers. Over the passage of time, this accumulation organizes and takes the form of sedimentary rocks.
Examples: Sandstone, Clay, etc.

Chemically Formed Sedimentary Rocks:
Flowing water dissolves the soluble substances in its path, transports them and sets their accumulation elsewhere, due to which these rocks are formed. Alabaster, Gypsum , Tufa are the examples of this type of rocks. In this type of rocks, the soluble substances dissolve with water. Later when the pressure decreases, the water turns into vapor or due to decrease in the speed of flowing water, these dissolved substances start settling down, due to which these rocks are formed.

Question 4.
Explain the differences between the Igneous Rocks and the Sedimentary Rocks.
Answer:
Following are the differences found between the Igneous Rocks and the Sedimentary Rocks.

Points of Difference	Igneous Rocks	Sedimentary Rocks
Formation	Igneous Rocks are formed when the magma and lava condense and solidify on cooling down in the internal part of earth.	Sedimentary Rocks are formed by the fragments of those ancient rocks and minerals, which are shattered completely and solidified in the form of layers.
Structure	These rocks are hard.	These rocks are soft.
Porosity	These rocks are not porous.	These rocks are porous.
Texture	Layers are not found in these rocks.	Layers are found in these rocks.
Crystals	These rocks are crystallized.	These rocks are not crystallized.
Fossils	Fossils of any kind are not found in these rocks.	Fossils are found between the layers of these rocks.
Minerals	Metallic minerals are found in these rocks.	Organic minerals are found in these rocks.
Erosion	The erosion of these rocks is very slow.	The erosion of these rocks is relatively faster.

Question 5.
Explain the importance of Sedimentary and Metamorphic Rocks.
Answer:
Importance of Sedimentary Rocks:
Sedimentary rocks are significantly important in terms of the human – use. Minerals and energy – resources are found in these rocks, like iron, mineral oil, coal, natural gas, etc. The hard sandstone is used in the construction of buildings. The process of agriculture has proved to be more useful in sedimentary rocks. Limestone is found in these rocks which is useful in iron and steel industry.

Importance of Metamorphic Rocks:
Metamorphic rocks hold a special place for the humans. Some very important minerals are found in these rocks like gold, silver, diamond etc. After the metamorphism, important rocks are formed like marble, graphite, magnetic iron, etc. All these rocks are used for diverse purposes. Sulphur mixed water sources are found in these rocks, bathing in which can cure many kinds of diseases.

Question 6.
Explain the classification of sedimentary rocks on the basis of the resources used in formation.
Answer:
Sedimentary rocks are formed by different types of materials. Various types of sediments are required for the accumulation of sedimentary rocks. These sediments are obtained by different mediums. On the basis of this accumulation, the sedimentary rocks are being classified into the following parts:

1. Aqueous Rock:
These rocks are formed by the accumulation of sediments which are carried by rivers from one place to another place. Due to their accumulation in aquatic parts, they are called the Aqueous Rock. These rocks are found mainly in the form of sea rock, lake rock and river rock.

2. Aeolian Rock:
Due to physical weathering in hot and dry regions, rocks which are formed by the accumulation of rocks – flour (made by breakdown of rocks), blown by the wind from one place to another place are called Aeolian Rocks. Due to rubbing of air – particles among themselves, they solidify on getting fine, thereby forming rocks, like – Loess.

3. Glacial Rocks:
These rocks are formed by the transportation and deposition of pebbles and boulders by the glaciers. These substances are collectively called Glacial Drift.

RBSE Class 11 Physical Geography Chapter 6 Essay Type Questions

Question 1.
Describe in detail the Hypabyssal Rocks formed in the internal part of earth.
Or
Describe the topographies formed by magma in the internal part of earth.
Answer:
Many topographies are formed by magma beneath the earth’s surface i.e. the internal part of earth. All these rocks are called Hypabyssal Rocks. A brief description of these rocks is as follows:

1. Batholith:
These are also known as depth rocks. These are igneous rocks extending to a long distance and are hundreds of kilo meters long and irregular. These rocks are dome-shaped. Their edges are like standing slope and base in deep depth. Their upper part is extremely irregular. At the time of formation of folded mountains, pieces obtained from fragmentation of rocks are helpful in their formation.

2. Lacolith:
This is also known as mushroom rock or kukuchail. This word is made from the Greek word ‘Lekosh’, whose meaning is – water reservoir. It is formed of magma, large in size and is in the form of convex slope. Its shape is generally arcuate and base is flat. It is formed only in the sedimentary rocks.

3. Phacolith:
It is also called masoor rock. It is a typically lens – shaped large rock. It is formed when magma solidified in the syncline of folded mountains at the time of volcanic eruption.

4. Lapolith:
It is a vast form of the magma. When a shallow basin of concave – shaped is formed beneath the earth’s surface, then the accumulation which is formed in the shape of a saucer is called Lapolith.

5. Sills:
It is also known as ralapatta. It is formed in the internal part of the earth, when the magma cools down and solidifies in the cracks of pre – formed rocks in a straight line. This layer of magma in the form of sills solidifies in parallel formations.

6. Dykes:
It is also known as ral bhitti. When magma solidifies in the vertical form in the cracks of rocks, then this is called Dykes. Dykes can range from a few centi – meters to hundreds of meters. Dykes are generally hard.

7. Sheet:
When magma accumulates horizontally in the cracks of rocks in an elongated and thin form, then it is called sheet. These topographies found in the internal part of earth are being presented with the help of the following fig.

Question 2.
Explain the types of metamorphism of the Metamorphic Rocks.
Answer:
The process of metamorphism of the Metamorphic Rocks are classified mainly into four parts:

1. Thermal Metamorphism:
When the rocks are exposed to magma at the time of volcanic activity, then the metamorphism takes place due to high heat in the rocks near the volcanic tube, this is called Thermal Metamorphism. Sometimes water gets mixed with the magma, due to which chemical changes also occur in rocks. This type of metamorphism takes place in limited area. Thus, its geographical importance, is very low.

2. Dynamic or Regional Metamorphism:
This type of metamorphism takes place in a vast area. Compression and heat both have the effect in it. This type of metamorphism occurs often in folded mountainous areas. This type of metamorphosed rocks become crystallized. If the original rock is already crystallized, then new formation of crystals begins in it in a new way.

3. Hydro Metamorphism:
In this type of metamorphism, change in the minerals of rock takes place in the form of a solution by mixing of chemical substances with water. Depth of excessive water also increases the weight and pressure. Due to this process, metamorphism in the rocks takes place.

4. Thermo – Hydro Metamorphism:
When there is hot water over the rocks, then due to pressure and water vapour, this type of metamorphism takes place in the rocks. Such type of metamorphism is not geographically important.

These forms of metamorphism are shown with the help of the following fig.

RBSE Solutions for Class 11 Geography