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(Download) UPSC: Geologist Main Examination Papers-2020

(Geology Paper-2)

Exam Name : UPSC Geo-Scientist and Geologist Main Exam

Subject : UPSC Geo-Scientist and Geologist Main Exam Papers 2020 : Geology Paper- 2

Year : 2020

Geology Paper - 2

Time Allowed : Three Hours
Maximum Marks : 200

SECTION A (Compulsory Section)

Q1. Describe the following in brief with diagrams, wherever necessary : 5x10=50

(a) Crystal defects

(b) Interference phenomenon in Petrological microscope

(C) Siderophile and Chalcophile elements

(D) Eu-anomaly and its significance

(e) Rapakivi texture

(f) Congruent and Incongruent melting

(g) Paired metamorphic belt

(h) Hornfelsic texture and its implications

(i) Difference between Seismic and Petrological Moho

(j) Kerguelen hotspot

SECTION B

Attempt any one question.
Q2. (a) Write the projection for C2h and D2h class and give its symmetry and Hermann-Mauguin symbols.

(b) Give an account on structure, chemistry and classification of Garnet group of minerals.
Q3. (a) Write the procedure to obtain conoscopic vision in a Petrological microscope. How would you determine optic sign of a uniaxial mineral ?

(b) Give an account on structural classification of silicate minerals with examples and neat sketches.
. (c) Explain Twin and Twin laws. Describe different types of twinning in Feldspars.

SECTION C

Attempt any one question.
Q4. (a) Give an account on classification, mineralogy and composition of meteorites.

(b) Define partition coefficient (Kp or D). Discuss Goldschmidt's Rules that govern chemical fractionation of elements in silicate melts.

(c) Using partition coefficients of compatible and incompatible elements, explain batch melting in magma evolution.

Q5. (a) What do you understand by isotopic fractionation ? Discuss isotopic evolution of the ocean. How is PDB (Pee Dee Belemnite) useful in the study of carbon isotopes ?

(b) Discuss mass fractionation and bond strength with suitable examples.

(c) Write the application of Radio-nuclei in geochronology and discuss the Sm - Nd system. : ::

SECTION D

Attempt any one question. ;

Q6. (a) What are petrographic characteristics of Kimberlites ? Add a note on . their tectonic setting.

(b) Explain the factors responsible for magma generation.

(c) What is an ophiolite suite ? Draw a neat sketch of an ophiolite section. Label and add a comment on each unit.

Q7. (a) What are the conditions to form Layered Igneous Complexes ? Give a brief account on Bushveld Layered Igneous Complex.

(b) Describe eutectic and peritectic crystallisation with reference to Forsterite – Silica T - X phase diagram. Add a note on corona formation.

(c) Explain Lever's rule. Find the composition and relative proportions of liquid and solid at points A, B and C in a given Albite - Anorthite phase diagram.

SECTION E

Attempt any one question.
Q8. (a) What are metamorphic facies and metamorphic facies series ? Give suitable examples.

(b) Describe Clausius-Clapeyron equation. Add a note on its applications to metamorphic reactions. Discuss in brief, the prograde regional metamorphism of pelitic rocks.
Q9. (a) Discuss in brief, the role of fluids in metamorphism.

(b) Give ideas with suitable examples on

(i) Retrograde metamorphism, and

(ii) ACF diagram. Describe with neat sketches the following textures : Helicitic and Cataclastic.

SECTION F

Attempt any one question.
Q10. (a) Explain seismic discontinuities within the Earth with suitable diagram. Mention the role of Olivine – Spinel phase transition in geodynamic setting.

(b) What are mantle plumes ? Discuss their origin and significance.
Q11. (a) Give evidences in support of Continental Drift theory.

(b) Briefly mention the Gravity and Magnetic anomalies of the ocean floor.

(c) Illustrate different types of plate boundaries and add a note on their inter-relationship.