BGYCT-135 · June 2022 · English
IGNOU BGYCT-135 June 2022 Previous Year Question Paper
PETROLOGY
Structured previous year question paper for BGYCT-135, June 2022 session.
Max marks: 50 · Questions: 4
Verified: 10 Aug 2026
BACHELOR OF SCIENCE (GENERAL)
(BSCG)
Term-End Examination
June, 2022
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 questions of the following : 5x2=10
(a) Define skewness.
(b) Distinguish between holocrystalline and holohyaline textures.
(c) Define essential and accessory minerals.
(d) Define phase diagram.
(e) List the processes of magmatic differentiation involved in the solid state of magma.
(f) List four intermediate rocks.
(g) Define sediment.
(h) What is diagenesis ?
(i) Distinguish between clastic and non-clastic rocks. G) Distinguish between allogenic and authigenic minerals.
Q2.Write short notes on any four of the following : 4x5=20
(a) Granularity
(b) Tabular Classification
(c) Intergrowth Texture
(d) Alkali-Lime Index
(e) Major Types of Magma
(f) | Importance of Bowen’s Reaction Series
(g) | Ripple Marks
(h) Schistosity
Q3.Answer any one of the following : 1x10=10
(a) Discuss briefly the forms found in igneous rocks with the help of neat well-labelled diagrams.
(b) Describe the megascopic and microscopic characters of gabbro.
Q4.(a) Write in brief about the kinds of sedimentary particles. 5
(b) Explain the reactions taking place during chemical weathering in rocks. 5
(a) Discuss in brief five structures found in igneous rocks. 5
(b) How will you identify granite in hand specimen ?