Geology IAS Paper 2 UPSC 2021 with Solutions
In this article, all questions of Geology Optional Paper 2 are answered. Click on the question links to view the answers.
This article is part of Synopsis IAS Geology Optional Course for UPSC IAS.
Geology Optional Paper 2 UPSC 2021 - Question Paper with Solutions
Click on the links for the solutions
SECTION-A
1. Answer the following questions in about 150 words each:
Geology 1a How does one designate mirror plane, rotational axes of symmetry and centre of symmetry in Hermann-Mauguin notation? A crystal has one 4-fold axis, four 2-fold axes, five mirror planes and centre of symmetry. What will be its Hermann-Mauguin notation? Show on a stereographic projection diagram the symmetry elements of the above crystal and plot the faces of the form (hkl). UPSC 2021, 10 Marks
Geology 1b Discuss with the help of a suitable diagram the crystallization of a melt having composition Diopside-70 and Anorthite-30 under 1 atmospheric pressure. After complete crystallization, what would be the texture of the rock? UPSC 2021, 10 Marks
Geology 1c Describe 'continuous' and 'discontinuous' reaction series of minerals proposed by Bowen. Why is one series called as 'continuous' and the other as 'discontinuous? UPSC 2021, 10 Marks
Geology 1d Define 'prograde' and 'retrograde' metamorphism with suitable examples. Discuss the process of metasomatism. UPSC 2021, 10 Marks
Geology 1e Give a brief account of Folk's classification of limestones. UPSC 2021, 10 Marks
Geology 2a Give the classification scheme of silicate minerals on the basis of atomic structure, Si: O ratio and number of shared oxygen. Give suitable examples of each class. UPSC 2021, 20 Marks
Geology 2b Define birefringence' and 'extinction angle' in minerals. How does one proceed to measure extinction angle of a mineral under microscope? Substantiate your answer with suitable sketches. UPSC 2021, 20 Marks
Geology 2c Define 'twin plane', 'twin axis' and 'composition plane' in crystals. State different types of twinning observed in feldspars. UPSC 2021, 10 Marks
Geology 3a Discuss briefly the processes of magma generation in the Earth's interior. How is grain size of an igneous rock related to the rate of cooling of magma? Discuss the role of fractional crystallization and assimilation in magmatic differentiation. UPSC 2021, 20 Marks
Geology 3b Describe with suitable sketches four different types of structures/textures found in metamorphic rocks and add brief notes on their origin. UPSC 2021, 20 Marks
Geology 3c Define 'migmatite'. How does the process of migmatization help to understand the origin of granites? UPSC 2021, 10 Marks
Geology 4a What is provenance? How can we use clastic quartz, feldspars and lithic grains in provenance interpretation of sandstones? UPSC 2021, 20 Marks
Geology 4b Define a 'sedimentary facies model'. Illustrate with neat sketches the sedimentary facies and association facies likely to develop in a meandering fluvial depositional environment. UPSC 2021, 20 Marks
Geology 4c Describe the genesis of any four sedimentary structures which have significance for palaeocurrent analysis. UPSC 2021, 10 Marks
SECTION-B
5. Answer the following questions in about 150 words each:
Geology 5a Lead (Pb) mineralization zone is drawn in the given diagram with nomenclature. The related data is also provided in the table. Calculate the average grade of lead (Pb) in percentage. UPSC 2021, 10 Marks
| Sample No. | Zone of Influence, L (ft) | Width, W (ft) | WxL (ft²) | % Pb |
|---|---|---|---|---|
| S-1 | 6.0 | 3.5 | 21.00 | 7.1 |
| S-2 | 7.5 | 2.5 | 18.75 | 7.5 |
| S-3 | 10.0 | 3.0 | 30.00 | 6.9 |
| S-4 | 12.5 | 3.5 | 43.75 | 8.9 |
Geology 5b Describe the geological nature of coal deposits of Jharia (Jharkhand) and comment on their economic potential. UPSC 2021, 10 Marks
Geology 5c What are geophysical methods of exploration? How is gravity method useful in mapping the metallic ores? UPSC 2021, 10 Marks
Geology 5d Define 'trace element'. Discuss the possible ways that a trace element can enter into a mineral structure. UPSC 2021, 10 Marks
Geology 5e State the sea level changes in Late Pleistocene period with possible causes. Add a note on anthropogenic causes occurred in last two centuries. UPSC 2021, 10 Marks
Geology 6a Give the modern classification of mineral deposits and explain in brief the residual and mechanical concentration deposits with suitable examples. UPSC 2021, 20 Marks
Geology 6b Stating the premise of National Mineral Policy, give the outline of strategic, critical and essential minerals citing Indian examples. UPSC 2021, 20 Marks
Geology 6c Give the mode of occurrence, distribution and uses of manganese deposits of India. UPSC 2021, 10 Marks
Geology 7a State the characteristic features of cosmic abundance of elements. What are the bases of estimation of cosmic abundance of elements? UPSC 2021, 20 Marks
Geology 7b Discuss briefly with examples about different types of chemical bonds observed in natural minerals. UPSC 2021, 10 Marks
Geology 7c Describe briefly the geology, structure and mode of occurrence of hydrocarbons in western oil fields of India. UPSC 2021, 20 Marks
Geology 8a How is unscientific development of catchments situated in mountainous regions responsible for increased threat of floods in plains? UPSC 2021, 10 Marks
Geology 8b Describe various types of radioactive wastes. Write an account on various methods of their disposal. UPSC 2021, 20 Marks
Geology 8c What is meant by waterlogging? Describe in detail the remedial measures of no waterlogging and salinity. UPSC 2021, 20 Marks