IAS Mains Geology Papers 1991

IAS Mains Geology 1991

Paper I

Section A

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

    1. Interior of the earth

    2. Sea-floor spreading

    3. Petrofabric analysis

    4. Principle of isostasy

  2. Discuss the role of running water as an agent of erosion and deposition. Describe some important geomorphic features produced by these processes.

  3. What kind of mountain are the Himalayas: Discuss how the Himalayas might have originated.

  4. Describe the common planar and linear structures found nature. Discuss their genetic significance.

Section B

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

    1. Pleistocene Glaciation

    2. Life during the Vindhyan times

    3. Modes of preservation of fossils

    4. Age of the Deccan traps

  2. Describe the morphological features of the brachiopods. Name five important brachiopod fossils from Indian formation.

  3. Give an account of animal life during the Siwalik times.

  4. Briefly discuss the stratigraphy of the Caddapah Group of South India.

Paper II

Section A

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

    1. Difference between crystalline and non-crystalline substances

    2. Phyllo-silicates

    3. Digenesis

    4. Magmatic differentiation

  2. What are optical accessories? How are they useful? Describe the construction of any one you know.

  3. Describe the plagioclase feldspar group of minerals.

  4. Discuss the problem of charnokites and charnockites.

Section B

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

    1. Caving methods

    2. Ore forming fluids

    3. Remote sensing method Hydrogeology

    4. Tertiary coal fields of India

  2. Give an account of the stratigraphic controls of mineral localisation.

  3. Write an essay on the National Mineral Policy.

  4. Give an outline of the methods of ore benefication.