IAS Mains Geology Papers 1990

IAS Mains Geology 1990

Paper I

Section A

  1. Explain any three of the following in about 200 words each:

    1. Petro fabric analysis as a tool in structural studies

    2. Drainage patterns

    3. Origin of continents and oceans

    4. Products of volcanic eruptions

  2. Write a short essay on ‘Geomorphic features of the Indian sub-continent’

  3. Answer the following questions

    1. What are joints? How do they differ from faults? Give a genetic and geometrical classification of joints.

    2. How does the repetition of beds differ due to folding and faulting?

  4. Distinguish between the members of the following pairs:

    1. Bedding Plane and Cleavage

    2. Esker and Kame

    3. Horst and Graben

    4. P-waves and S-waves

    5. Solution valley and Glacial valley

Section B

  1. Answer any three of the following in about 200 words:

    1. Extinction of Dinosaurs

    2. Evidences of first marine transgression in South India during mesozoic and related stratigraphic unit/units.

    3. Permian-Triassic Boundary

    4. Microfossils and their significance

  2. Give in a tabular form the stratigraphic succession, lithology and characteristic fossils of the Siwalik System. Discuss the conditions of deposition and climatic factors during that period.

  3. Draw a neat, full-page-size labelled diagram in illustrate the external morphology of:

    1. a Gastropod

    2. Trilobita

    Name two genera, from each of the above groups from Indian stratigraphy mentioning their stratigraphic horizon.

  4. Discuss the following:

    1. Gondwana flora climatic vicissitudes and stratigraphic classification of the supergroup

    2. Recent developments in Dharwarian stratigraphy

Paper II

Section A

  1. Write notes on any three of the following in about 200 words each:

    1. International system of crystallographic solution

    2. Use of stereographic projections to represent symmetry

    3. Biaxial indicatrix

    4. Ionic radii coordination number

  2. Discuss in detail application of X-rays for crystal studies.

  3. What is the difference between pleochroic and interference colours? Explain how these colours are produced in minerals.

  4. Give an account of the physical, chemical and optical properties of pyroxene group of minerals.

Section B

  1. Write notes on any three of the following in about 200 words each:

    1. Facies and grades of metamorphism

    2. Metallogenetic epochs

    3. Bowen's Reaction in Principle

    4. Ore dressing and benefication

  2. Give a brief account of the oil and gas fields of India with particular reference to post-independence discoveries.

  3. Give an account of textures present in sedimentary rocks and discuss their significance.

  4. Discuss in detail the use of aerial photographs in geological investigations.