IAS Exam : Prelims Geography Goh Cheng Leong Questions:The Earth’s Crust

1.    Consider the properties of sedimentary rocks

1.    It is formed from sediment accumulated over long periods.
2.    It is stratified
3.    It is non crystalline and often contain fossils.

Select the correct answer from following codes

a.    Only 1 and 2
b.    Only 1and 3
c.    Only 1
d.    1,2 and 3

Answer: d

Explanation : Sedimentary rocks are formed from sediment accumulated over long periods, usually under water.

2.    Which of the following pairs are correctly matched

Rocks                     metamorphosed

1.    Clay            -      slate
2.    Sandstone    -     schist
3.    Limestone     -     marble

Select the correct answer using following codes

a.    Only 3
b.    Only 1 and 3
c.    Only 2 and 3
d.    1,2 and 3

Answer: b

Explanation : All rocks may become metamorphosed rocks under great heat and pressure. Clay- slate, limestone- marble, sandstone- quartzite, granite- gneiss, shale- schist, coal- graphite.

3.    Which of the following forces shape the face of earth?

1.    Sun
2.    Running water
3.    Frost

Select the correct answer using following codes

a.    Only 2
b.    Only 1 and 2
c.    Only 1 and 3
d.    1,2 and 3

Answer: d

Explanation : The face of the earth is constantly reshaped by agents of denudation- running water, rain, frost, sun, wind, glaciers and waves.

4.    Fold mountains are formed by which of the following?

1.    Flow movements in mantle
2.    Expansion or contraction of some part of earth
3.    Increased load of overlying rocks

Select the correct answer using following codes

a.    Only 2
b.    Only 1 and 2
c.    Only 2 and 3
d.    1,2 and 3

Answer: d

Explanation : Fold Mountains are caused by large scale earth movements, when stresses are set up in earth crust. Stresses may be due to increased load of overlying rocks, flow movements in mantle, magmatic intrusions into the crust, expansion or contraction of some part of earth.

5.    Which of the following statements are true about Fold Mountains?

1.    They are not closely associated with volcanic activity.
2.    They contain rich minerals such as tin, copper, gold.

Select the correct answer using following codes

a.    Only 1
b.    Only 2
c.    Both 1 and 2
d.    Neither 1 nor 2

Answer: b

Explanation : They are closely associated with volcanic activity. They contain many active volcanoes especially in the circum pacific fold mountain system. They also contain rich mineral resources such as tin, copper, gold and petroleum.

6.    Which one of the following is not agent of erosion?

a.    Rain and Running water
b.    ice
c.    winds
d.    none

Answer: d

Explanation : Running water, ice, rain, and winds are agents of erosion and weathering.

7.    Consider the following statements

1.    Rocks formed by either volcanic activity or plutonic activity are called igneous rocks.
2.    Sedimentary accumulations on a larger scale are of various types like laccoliths, lopoliths,   phacoliths and batholiths.

Select the correct answer from the following codes

a.    Only 1
b.    Only 2
c.     Both 1 and 2
d.    Neither 1 nor 2

Answer: a

Explanation : Igneous intrusions on larger scale are the various types laccoliths, lopoliths, phacoliths and batholihs. Laccolith- dome shaped igneous mound, lopolith- saucer shaped igneous intrusion, phacolith- lens shaped igneous rocks, batholiths- huge mass of igneous rocks usually granite.

8.    Consider the following statements regarding lavas of volcanoes

1.     Basic lavas are dark coloured and poor in silica.
2.    Acid lavas are light coloured and have high percentage of silica.

Select the correct answer from the following codes

a.    Only1
b.    Only 2
c.    Both 1 and 2
d.    Neither 1 nor 2

Answer: c

Explanation: Basic lavas are hottest lavas, highly fluid and affect extensive areas, dark coloured like basalt, rich in iron and magnesium but poor in silica. Acid lavas are highly viscous, light coloured and low density, have high percentage silica, flow slowly, result in loud explosions.

9.    Consider the statements regarding distribution of volcanoes.

1.    Locations of volcanoes are closely related to regions that have been intensely folded or faulted.
2.    They occur along coastal mountain ranges, midst of oceans
3.    They also occur in interiors of continent.

Select the correct answer from following codes

a.    Only 1
b.    1 and 2 only
c.    Only 2
d.    1,2 and 3

Answer.d

Explanation : Volcanoes occur in intensely folded or faulted region. They occur along coastal mountain ranges as off-shore islands and in midst of oceans, but there are few in interiors of continents. Greatest concentration occurs in circum-pacific region, popularly termed ‘pacific ring of fire’ which includes worlds 2/3rd volcanoes.

10.    Consider the following statements

1.    Volcanoes occur in intensely folded and faulted region.
2.    The Himalayas have, surprisingly, no active volcanoes at all.

Select the wrong statements

a.    Only 1
b.    Only 2
c.    Both 1 and 2
d.    Neither 1 nor 2

Answer: c

Explanation: Even though Himalayas is young fold mountain. It is has no active volcano at all.

Click here for more Geography Questions and Study Material