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Combined Geo-Scientist (Main)
Examination, 2024 SGSE-M-GLG
GEOLOGY
PAPER—II
Time Allowed : Three Hours Maximum Marks : 200
QUESTION PAPER SPECIFIC INSTRUCTIONS
Please read each of the following instructions carefully
before attempting questions
There are ELEVEN questions divided under SIX Sections.
Candidate has to attempt SIX questions in all.
The ONLY question in Section—A is compulsory.
Out of the remaining TEN questions, the candidate has to attempt FIVE, choosing ONE
from each of the other Sections B, C, D, E and F.
The number of marks carried by a question/part is indicated against it.
Unless otherwise mentioned, symbols, abbreviations and notations have their usual
standard meanings.
Neat sketches are to be drawn to illustrate answers, wherever required. They shall be
drawn in the space provided for answering the question itself.
Wherever required, graphs/tables are to be drawn on the Question-cum-Answer (QCA)
Booklet itself.
Attempts of questions shall be counted in sequential order. Unless struck off, attempt of a
question shall be counted even if attempted partly.
Any page or portion of the page left blank in the Question-cum-Answer (QCA) Booklet
must be clearly struck off.
Answers must be written in ENGLISH only.
SGSE-M-GLG/64 1 ]۶۷۵
SECTION—A
( Compulsory Section )
1. Describe the following in brief with diagrams and suitable examples, wherever
necessary : 5×10=50
(a) Flash figure
(0) Perthite
(c) Global Meteoric Water Line
(व) Carbonate compensation depth and lysocline
(e) Soret effect
6 +Rapakivi texture
(g) Geothermal gradient
(h) Diffusion and mass transfer
¢ Heat flow in the crust
7 Seamounts
SECTION—B
Attempt any one question
2. (a) Describe the different types of defects in crystals.
(b) Zircon and rutile crystallize in the 4/m 2/m 2/m class. Describe the five
forms that develop in crystals of this class
૩. (a) Give the classification of rock-forming minerals on the basis of degree of
polymerization of [SiO,] tetrahedra and name the important mineral groups
in each.
(b) With examples, explain isotypous and polymorphism in minerals.
(c) Describe the physical characters and give the chemical composition of the
nesosilicate group minerals which crystallize in isometric system.
SGSE-M-GLG/64 2
15
15
10
10
10
(b)
(৮)
(0
6. (a)
(b)
धि
(0
8. (a)
(b)
SECTION—C
Attempt any one question
Explain, with Eh-pH diagrams, the difference in geochemical behaviour of iron
and manganese that leads to their spatial and stratigraphic separation.
Describe the processes that are involved in the carbon fluxes between
atmosphere, ocean, biosphere and lithosphere, and explain the working of the
carbon cycle.
Describe the Sm-Nd dating method. Add a note on its application in petrology.
Describe the applications of K-Ar and 4041 - 39 Ar dating methods in igneous,
metamorphic and sedimentary rocks.
Describe briefly the isochron method; and explain how it overcomes the
limitations of radiometric age calculations.
SECTION—D
Attempt any one question
What are the major components which influence the flow of magma? How does
compositional variation develop in primary magma?
Write about the principles of IUGS classification of igneous rocks.
How are fabrics used as tool to decipher the genesis of igneous rocks? Discuss
the various textures with suitable diagrams.
Describe the potash-rich basic volcanic rocks. How are these rocks different
from the spilitic-keratophyre rocks?
Discuss, with the help of a phase diagram, how the chromite layers developed
in the Bushveld Layered Mafic Complex.
SECTION—E
Attempt any one question
Explain the concept of facies. Describe, with a neat P-T diagram, the general
facies formed during regional dynamothermal metamorphism. Mention their
approximate equivalent facies in contact metamorphic aureoles.
With neat sketches, describe the structures and textures observed in
metamorphic rocks. Add a note on their significance in understanding
metamorphic conditions.
15
15
10
10
10
15
15
10
10
10
15
15
SGSE-M-GLG/64 3 | ~ 9.
9. (a) Explain enthalpy, entropy and Gibbs’ free energy, and their relation to
metamorphic process. ন 10
(b) With examples and neat sketches, discuss the application of ACF and AKF
diagrams to represent metamorphic assemblages. 10
(c) Discuss the process involved in the formation of skarns. 10
SECTION—F
Attempt any one question
10. (a) What do you understand by phase transitions? Explain them in relation to
seismic discontinuities in the earth. 15
(b) Which are the different plate boundaries? Bring out the interrelationship
among them with neat diagram. 15
11. (a) What is rock magnetism? Discuss its importance in understanding polarity
reversals. 10
(b) How are hot spots formed? How are they related to breaking up of continents? 10
(c) What do you understand by intraplate earthquakes? Discuss on the intraplate
earthquakes of India. 10
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SGSE-M-GLG/64 4 SB24—432
