8th Std G2 LITHOSPHERE

 by Veeresh. P

Geography

LITHOSPHERE

I Fill in the blanks with suitable words :

1. The continental crust is also called ___________

2. Vast basin shaped volcanic mouth is ___________

3. The most destructive earthquake waves are ________

4. Stalactites and stalagmites are most common in _______

5. The Beaches are formed by ________ work.

Ans: (1) SlAL, (2) Caldera, (3) surface waves,

(4) lime stone region, (5) sea waves.

II. Answer the following questions:

1. Mention the three major layers of the interior of the Earth.

Ans: The three major layers of the interior of the Earth are

(1) The Crust (2) The Mantle and (3) The Core.

2. Name the types of volcanoes on the basis of frequency of eruption.

Ans: On the basis of frequency of eruption volcanoes are classified into three types. They are-(1) Active Volcanoes, (2) Dormant Volcanoes and (3) Extensive Volcanoes.

3. Mention the important earthquake zones of the world.

Ans. The important earthquake zones of the world are-

(1) The Circum-Pacific Belt-Regions around the Pacific Ocean (New Zealand, Philippines, Japan, USA, Peru, etc.)

(2) The Mediterranean Belt- Regions around the Mediterranean Sea.

(3) The Himalayan Belt- The Siwalik regions of India.

4. What is weathering? Name the three main types of weathering.

Ans: Weathering is the wearing away or breaking down or gradual disintegration of rocks by agents like temperature, rainfall, wind etc., present in the atmosphere.

The three types of weathering are as follows-

(1) Mechanical weathering,

(2) Chemical weathering and

(3) Biological weathering.

5. Name the landforms associated with the work of river.

Ans: The important landforms in the middle course of the river are Alluvial fans and Meanders. The important land forms in the Lower Course of the river are flood Plains, Natural Levees, Ox-bow lakes, Deltas.

III. Match the following:

A B

1. Sima a) Earthquake

2. Sandstone b) Yellow soil

3. Epicentre c) Oceanic crust

4. Geyser d) sedimentary rock

5. Loess e) underground water

Ans: 1-c, 2-d, 3-a, 4-e, 5-b.

IV. Define the following:

1. Aqueous rocks: Sedimentary Rocks are also called aqueous rocks because they are formed in the water bodies like lakes, seas, and ocean beds.

2. 'Pacific ring of fire': Pacific ring of fire is a region of Volcanoes. The regions are The Coastal margins of the Pacific Ocean

consisting of Philippines, Japan, USA, Central America, South America, etc.

3. Mechanical weathering: When the rock is broken and disintegrated without any chemical alteration, the process is called Physical weathering or Mechanical weathering. The important processes of mechanical weathering are Granular disintegration, Block disintegration and Exfoliation. The agents of mechanical weathering are temperature, wind, frost, etc.

4. Carbonaceous rocks: Coal is called carbonaceous rock. Organic sediments are derived by the accumulation of remains of organisms, such as shells of marine organisms, remains of plants and animals, Example Carbonaceous rocks are coal and limestone.

5. Tsunami: Tsunami is a large sea wave occasionally experienced along the coasts of Japan and in other regions caused by underwater earthquake. In Japanese language 'Tsunami' means 'harbour waves'.

6. Continental glacier: Continental glacier are extensive ice sheets found in polar regions E.g. Greenland and America.

7. Hot spring: Whenever warm or hot water comes out naturally it is called hot spring or thermal spring. They are usually found near the volcanic regions.