BGYCT-135 · June 2023 · English
IGNOU BGYCT-135 June 2023 Previous Year Question Paper
PETROLOGY
Structured previous year question paper for BGYCT-135, June 2023 session.
Max marks: 50 · Questions: 4
Verified: 10 Aug 2026
B. Sc. (GENERAL) (BSCG)
Term-End Examination
June, 2023
BGYCT-135 : PETROLOGY
Time : 2 Hours Maximum Marks : 50
Note :
(i) All questions are compulsory.
(ii) Marks allotted for each question are
indicated against it.
(iii) Draw well-laballed diagrams, wherever
necessary.
Q1.Briefly answer any five of the following questions : 5x2=10
(a) What is an outcrop ?
(b) Define graphic texture.
(c) Differentiate between essential and accessory minerals.
(d) List the factors governing crystallization of magma.
(e) What is phase rule ?
(f) How would you distinguish between granite and granodiorite ?
(g) What is sediment ?
(h) Differentiate between the mineral composition of quartzite and marble.
(i) What is porphyroclastic texture ? G) What is a ripple mark ?
Q2.Write short notes on any four of the following : 4x5=20
(a) Igneous rocks
(b) Granularity
(c) Tabular classification of igneous rocks
(d) Bowen’s Reaction Series
(e) Physical weathering
(f) Graphical presentation of grain size data
(g) Sole structures
(h) Contact metamorphism
Q3.Answer any one of the following : 1x10=10
(a) Discuss in detail the various types of cross bedding with the help of neat well-labelled diagrams.
(b) Describe the megascopic and microscopic characters of basalt and gabbro.
Q4.(a)
(0) Give an account of the common processes involved in meta- morphism. 5 Gi) Explain the process of devitrification.5
(b)
(i) What is Conglomerate ? Discuss the difference between conglomerate and breccia. 5 Gi) What do you understand by metamorphic grade ? Discuss the grades of metamorphism.