UPSC Geo Scientist 2025 Prelims Paper II (Geology/Hydrogeology) Question Paper (09-Feb-2025)

Question 1

Match the List-I with List-II and select the correct answer using the code given below the lists:

List-I (Soil type)	List-II (Description)
A. Histosols	1. Soils with a subsurface horizon of clay accumulation, highly leached; commonly found in humid tropical and subtropical climates.
B. Oxisols	2. Soils with a thick upper layer very rich in organic matter (0.25%) and containing relatively little mineral material.
C. Ultisols	3. Very old, highly leached soils with subsurface accumulation of iron and aluminium oxides, commonly found in tropical environments.
D. Vertisols	4. Soils that develop deep, wide cracks when dry (shrink and swell) due to high clay content (0.35%) and are not highly leached.

Code:

	A	B	C	D
(a)	4	3	1	2
(b)	2	1	3	4
(c)	2	3	1	4
(d)	4	1	3	2

Accepted Answer

A-2, B-3, C-1, and D-4

Answer

A-4, B-3, C-1, and D-2

Answer

A-2, B-1, C-3, and D-4

Answer

A-4, B-1, C-3, and D-2

Question 2

Consider the following statements regarding seismic waves :
Statement 1: The seismic waves follow curved paths.
Statement 2: The velocity of seismic waves generally increases with depth the result of increasing pressure that squeezes the rock into a more compact, rigid material.
Which one of the following is correct in respect of above statements?

Accepted Answer

Both statement 1 and statement 2 are true and statement 2 is the correct explanation of statement 1.

Answer

Statement 1 is false but statement 2 is true.

Answer

Both statement 1 and statement 2 are true and statement 2 is not the correct explanation of statement 1.

Answer

Statement 1 is true but statement 2 is false.

Question 3

Consider the following statements :Statement 1: Residence times of chemicals in the atmosphere are usually longer than those in the oceans.Statement 2: In terms of total mass, the atmosphere is a smaller reservoir than the oceans, and fluxes into and out of the atmosphere can be larger.Which one of the following is correct in respect of above statements?

Accepted Answer

Statement 1 is false but statement 2 is true.

Answer

Both statement 1 and statement 2 are true and statement 2 is the correct explanation of statement 1.

Answer

Statement 1 is true but statement 2 is fals

Answer

Both statement 1 and statement 2 are true and statement 2 is not the correct explanation of statement 1.

Question 4

Which one of the following pairs is not correctly matched ?

Accepted Answer

Cinder Cones : A bowl-shaped pit found at the summit of most volcanic mountains, surrounding the central vent

Answer

Stratovolcanoes : Mount Fuji in Japan is an example

Answer

Calderas : Large steep walled, basin-shaped depression much larger than crater

Answer

Diatremes : Kimberlite pipes are perhaps most exotic diatremes

Question 5

Considering that there is no erosion and the thickness of the crust is doubled, the change of elevation because of isostasy would be roughly:

Accepted Answer

20%

Answer

40%

Answer

50%

Answer

10%