BGYCT-135 · December 2023 · English
IGNOU BGYCT-135 December 2023 Previous Year Question Paper
PETROLOGY
Structured previous year question paper for BGYCT-135, December 2023 session.
Max marks: 50 · Questions: 3
Verified: 10 Aug 2026
BACHELOR OF SCIENCE (GENERAL)
(BSCG)
Term-End Examination
December, 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-labelled diagrams, wherever
necessary.
Q1.Briefly answer any five of the following questions : 5x2=10
(a) How do you define a rock ?
(b) What are the components of texture in an igneous rock ?
(c) How do you classify igneous rocks on the basis of colour index ?
(d) List the major types of magma on the basis of composition.
(e) What is triple point ?
(f) Distinguish between texture of rhyolite and granite.
(g) What are the three kinds of sedimentary particles ?
(h) List any ten metamorphic minerals.
(i) What are stromatolites ? (j) What are the three stages of diagenesis ?
Q2.Write short notes on any four of the following : 4x5=20
(a) Sedimentary rocks
(b) Porphyritic texture
(c) Physical properties of magma
(d) Assimilation
(e) Grain size
(f) Bedding and stratification
(g) Protolith
(h) Palimpsest texture
Q3.Answer any one of the following : 1x10=10
(a) Explain the low- and high-pressure limits of metamorphism.
(b) Discuss in detail any five structures of igneous rocks. 4
(a)
(i) Discuss any five common varieties of limestone. 5 Gi) What is metamorphic facies ? Discuss the important metamorphic facies of low pressure. 5
(b)
(i) Discuss the importance of Bowen's Reaction Series. 5 Gi) Explain the processes of magmatic differentiation in fluid state of magma.