UPSC Mains GEOLOGY-PAPER-II 2023

How are the symmetry elements in a crystal of class 6/m 2/m 2/m oriented with respect to its crystallographic axes?

Why do some minerals show pleochroism? Explain.

Describe the compositional changes in the magnesium-rich magma due to progressive removal of olivine.

Given a mafic protolith, what would be the characteristic mineral assemblages in (i) greenschist facies, (ii) amphibolite facies and (iii) granulite facies metamorphism?

Explain the diagenetic changes in carbonate rocks.

How does the Bragg equation explain X-ray diffraction from a crystal?

How does Si-O polymerism help to classify silicate minerals? Give one example for each of these silicate subclasses.

List all major differences among kaolinite, smectite and illite groups of clay minerals.

Describe the changes in crystallized solid composition in albite-anorthite system at 1 atm pressure during cooling of a liquid of An 50 composition from 1500 °C temperature.

How is a granite defined? Discuss petrogenesis of a calc-alkaline peraluminous granite.

What are the assumptions involved for plotting quartz-bearing metamorphic rocks of basaltic composition in an ACF triangular diagram?

Classify the conglomerate rocks on the basis of clast composition and grain-matrix ratio and discuss their genetic importance.

Briefly describe the mechanisms of gravity-controlled sediment flows and write about their characteristic features in the rocks.

Explain mineral-based techniques to decipher the source terrains and transport history of sediments. Give a list of minerals diagnostic of igneous and metamorphic provenances.

Explain the process of manganese nodules formation and give their major occurrences in the world.

Describe the formation of replacement textures in ore minerals and give the criterion of their recognition.

Explain the Kriging method for estimating ore reserve.

Discuss environmental impacts of urbanization and their mitigations with special reference to land and water.

How does coordination number depend on the ratio of ionic radii in a crystal?

Describe the formation of Banded Iron Formation (BIF) during Precambrian metallogenic epoch. Write a note on the Indian BIF deposits.

Discuss the late magmatic ore-forming processes. What are the salient field characters of such ore deposits?

Describe the origin of porphyry copper deposits. Give the geological setup of one porphyry copper deposit of India.

Give an account of external changes in flora due to the presence of anomalous concentration of base metal in a terrain.

Explain the principle for flotation as a benefication technique. Name various parameters that regulate the flotation process. Explain frothing method giving appropriate examples.

What do you understand by the term 'industrial minerals'? Give examples of any five industrial minerals, their sources, compositions and uses in the industry.

Discuss the causes of various seismic discontinuities in the upper mantle.

Discuss the composition, source, types, environmental hazard and utility of fly ash.

Discuss the hazards in active volcanic terrain during and after eruption.