BGYCT-135 · December 2024 · English
IGNOU BGYCT-135 December 2024 Previous Year Question Paper
PETROLOGY
Structured previous year question paper for BGYCT-135, December 2024 session.
Max marks: 50 · Questions: 4
Verified: 10 Aug 2026
BACHELOR OF SCIENCE (GENERAL)
(BSCG)
Term-End Examination
December, 2024
BGYCT-135 : PETROLOGY
Time : 2 Hours Maximum Marks : 50
Note : All questions are compulsory. Marks allotted
for each question are indicated against it.
Draw well-labelled diagrams, wherever
required.
Q1.Briefly answer any five of the following questions : 5x2=10
(a) Define rock.
(b) What are extrusive igneous rocks ?
(c) What are clastic rocks ? (१) List the causes of metamorphism.
(e) What is lithification ?
(f) Differentiate between crystallite and microlite.
(g) Distinguish between’ essential and accessory minerals.
Q2.Write short notes on any four of the following : 4x5=20
(a) Phase rule
(b) Importance of Bowen’s reaction series
(c) Mineralogy and texture of granite in hand- specimen
(d) Types of sediment load.
(e) Schistose texture
(f) Limestone
Q3.Answer any one of the following questions :
(a) Elaborately discuss the classification of sedimentary rocks based on chemical and mineralogical composition.
(b) Describe in detail the classification of igneous rocks based on _ chemical composition.
Q4.(a) Explain the four components of clastic texture. 5
(b) Give an account of uses of rocks. 5
(a) Discuss briefly the megascopic and microscopic characters of basalt. 5
(b) What is magma ? Add a note on the physical properties of magma. 5 ARE FAL! aif!