BGYCT-135 · June 2025 · English
IGNOU BGYCT-135 June 2025 Previous Year Question Paper
PETROLOGY
Structured previous year question paper for BGYCT-135, June 2025 session.
Max marks: 50 · Questions: 4
Verified: 10 Aug 2026
B. SC. (GENERAL)
(BSCG)
Term-End Examination
June, 2025
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 necessary.
Q1.Briefly answer any five of the following questions : 5x2=10
(a) Define rocks.
(b) Differentiate between sediment and sedimentary rock.
(c) What is degree of crystallization ?
(d) What is colour index ?
(e) What is assimilation ?
(f) Mention the significance of sediment sorting.
(g) Differentiate between matrix and cement.
(h) Define metamorphism.
Q2.Write short notes on any four of the following : 4x5=20
(a) Classification of metamorphic rocks
(b) Contact metamorphism
(c) Types of non-clastic rocks
(d) Grain size parameters
(e) Rock cycle
(f) Bowen's reaction series
Q3.Answer any one of the following : 10
(a) Discuss in detail the physical properties and composition of magma.
(b) Describe the megascopic and microscopic characters of rhyolite and granite.
Q4.(a)
(i) Give an account of the common processes involved in magmatic differentiation. 5
(ii) Discuss the types of sediment load.
(b)
(i) Describe any _ five primary structures found in sedimentary rocks. 5
(ii) Describe any five types of textures found in igneous rocks.