Geology UPSC PYQ 2025

Answer the following questions in about 150 words each: <!--qid:MAINS_2025_Geology-I_Q1-->

(a) What are migmatites? Describe the important types of migmatites and the processes of their formation. (b) Draw a neat labelled sketch for the albite-anorthite phase diagram (1 atm, dry). Trace the course of crystallization of an initial melt Ab20-An80 within this system. How can you interpret zoning in plagioclase with this system? <!--qid:MAINS_2025_Geology-II_Q3-->

Answer the following questions in about 150 words each: <!--qid:MAINS_2025_Geology-I_Q5-->

Answer the following questions in about 150 words each : <!--qid:MAINS_2025_Geology-II_Q1-->

(a) Discuss the direct and indirect geochemical methods used for prospecting of hydrocarbon deposits. (b) What are the physiological and morphological changes of the plants helpful in geobotanical prospecting of copper, manganese and uranium deposits? Add a note on commonly found plant indicators for zinc. (c) What do you understand by 'tonnage factor'? Discuss the geometric and graphic methods used in reserve calculation. <!--qid:MAINS_2025_Geology-II_Q7-->

(a) Discuss the genesis of any four sedimentary structures which are helpful in palaeocurrent analysis. How are the palaeocurrent patterns helpful in establishing the depositional environment? (b) Discuss the concept of facies model and give a brief account of deltaic facies model. (c) What are conglomerates? Describe their fabrics, classification and geological significance. <!--qid:MAINS_2025_Geology-II_Q4-->

(a) Give an account of geology, mode of occurrence, genesis and distribution of Pb-Zn deposits of Aravalli region. (b) Give the distribution of petroliferous basins of India. Discuss the geology of Cambay Basin. (c) Give a brief account on the volcanogenic massive sulphide (VMS) deposit. Cite suitable Indian examples. <!--qid:MAINS_2025_Geology-II_Q6-->

(a) What do you understand by isomorphism and polymorphism? Discuss monotropy by citing example of diamond and graphite. (b) What are the most important conditions necessary for safe disposal of radioactive waste in geological repositories? Add a note on the concept of multiple barriers to protect biosphere and hydrosphere. (Give suitable diagrams wherever necessary.) (c) What are the major environmental considerations while treating with the disseminated precious metal mine waste? <!--qid:MAINS_2025_Geology-II_Q8-->

Answer the following questions in about 150 words each : <!--qid:MAINS_2025_Geology-II_Q5-->

(a) Give a detailed account related to the classification of crystals into different crystallographic systems based on symmetry elements. (b) Describe the structure of the pyroxene group of minerals with suitable diagrams. Discuss the chemical compositions and optical properties of orthopyroxene. (c) Describe the structural classification of silicates with neat sketches. Give one example for each type. <!--qid:MAINS_2025_Geology-II_Q2-->