Synopsis IAS
  • Profile
    • New Student
      New to Synopsis IAS?Create an account to register.
      Register

    • Already Registered
      Login to buy courses.
      Log In

  • Home
  • Courses
  • Blog
  • PYQs (GS & Optional)
  • Geology Optional 2025 Paper With Solution

    • Geology Optional 2025 Paper 1 With Solution
      • Discuss the position of Astroid belt within the solar system and comment on the composition of meteorites.
      • What are sheath folds? Discuss the deformational conditions of their formation.
      • What is Global Positioning System (GPS)? Explain its geological applications.
      • Discuss the statement giving suitable examples. "Physical weathering adds to the effectiveness of Chemical weathering".
      • Discuss the types of Penetrative and Non-penetrative lineations with the help of suitable diagrams and throw light on their genesis.
      • What do you understand by continental drift? Discuss various geological evidences in favour of continental drift.
      • Geomorphic diversity is controlled by a number of endogenic and exogenic processes. Discuss this statement.
      • Describe morphotectonic features characteristic of rejuvenation in a mountaineous terrain.
      • Waves are responsible for modifying the coastal geomorphology. Justify the statement giving suitable examples and neat diagrams.
      • Explain how the Remote Sensing and Geographic Information System (GIS) may help in delineation of Groundwater potential zone?
      • Using neat sketches describe various types of Thrust geometries formed in a compressional regime.
      • On the basis of dip isogons describe the classification of folds with neat diagrams.
      • What are volcanoes? Describe various causes and products of volcanism.
      • How does strain analysis help in understanding the nature of rock deformation? Discuss centre to centre method of estimation of two dimensional strain.
      • Discuss favourable conditions for fossilization.
      • Discuss different concepts of biozonation with neat diagrams.
      • Describe the lithology, type locality, age and depositional environment of Blaini Boulder Bed.
      • What engineering properties make Marble, Sandstone and Granite useful as building stone?
      • Explain different generic types of water and their significance in water supply.
      • Discuss the evolutionary lineage of Equidae and comment on its migration.
      • Give the lithostratigraphic classification and distribution of Delhi Supergroup. Also comment on the economic significance of this supergroup.
      • What are different types of wells used for the extraction of groundwater? How and why the well field should be protected?
      • What do you understand by boundary problems in stratigraphy? Discuss Cretaceous/Palaeogene (Cretaceous/Tertiary) boundary problem giving Indian examples.
      • What are the important groups of microfossils? Add notes on their composition and significance.
      • Why Earthquake resistant structures are needed? Discuss the geological considerations required for developing the Earthquake resistant structures.
      • Discuss the interrelationship amongst Porosity, Permeability and Hydraulic conductivity. How are they important in groundwater movement? A sediment sample with a cross-sectional area of 0.02 m² is tested in a permeameter with a length of 30 cm. Water flows through the sample at a rate of 0.08 m³/sec with a head difference (h₁–h₂) of 20 cm. Calculate the Hydraulic conductivity.
      • Describe important Lower Gondwana plant fossils with the help of neat diagrams and comment on their palaeobiogeographic significance.
      • Discuss the lithology, fossil content and age of Palaeozoic sequence of Spiti Basin of Himachal Pradesh.
    • Geology Optional 2025 Paper 2 With Solution
      • Describe the symmetry elements shown by the normal class of the orthorhombic system. What are the different forms for this class? Draw the sketch stereogram of the form (hkl). Give examples of two minerals that crystallize in this system.
      • Discuss in brief the characteristic optical properties of hornblende and augite under petrological microscope.
      • Draw a neat labelled diagram for perthite texture. Explain the formation of perthite with the help of a suitable phase diagram.
      • With the help of diagrams, describe the various diagenetic textures of carbonate rocks.
      • Describe ultrahigh-pressure and ultrahigh-temperature metamorphism.
      • Give a detailed account related to the classification of crystals into different crystallographic systems based on symmetry elements.
      • Describe the structure of the pyroxene group of minerals with suitable diagrams. Discuss the chemical compositions and optical properties of orthopyroxene.
      • Describe the structural classification of silicates with neat sketches. Give one example for each type.
      • What are migmatites? Describe the important types of migmatites and the processes of their formation.
      • 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?
      • Briefly write on the characteristics of I, S, M and A type granites. Elucidate the petrographic and petrogenetic attributes for each type.
      • Write a brief account on the Deccan Flood Basalt Volcanism in India.
      • 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?
      • Discuss the concept of facies model and give a brief account of deltaic facies model.
      • What are conglomerates? Describe their fabrics, classification and geological significance.
      • What do you understand by metallogenic epochs and provinces? Discuss any two major metallogenies in India.
      • Discuss the mode of occurrence, origin and distribution of gold deposits in India.
      • What do you understand by 'pathfinder' elements? What are the elements/ions used in the prospecting of sulphides of epigenetic origin, porphyry copper deposit and sulphide deposits in general?
      • Define gravitation. What are the corrections necessary to obtain the absolute value of gravity (g) while using gravity method in mineral exploration?
      • What are the major components of chondrites? Discuss the mineralogical and textural features, and significance of chondrites.
      • Give an account of geology, mode of occurrence, genesis and distribution of Pb-Zn deposits of Aravalli region.
      • Give the distribution of petroliferous basins of India. Discuss the geology of Cambay Basin.
      • Give a brief account on the volcanogenic massive sulphide (VMS) deposit. Cite suitable Indian examples.
      • Discuss the direct and indirect geochemical methods used for prospecting of hydrocarbon deposits.
      • 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.
      • What do you understand by 'tonnage factor'? Discuss the geometric and graphic methods used in reserve calculation.
      • What do you understand by isomorphism and polymorphism? Discuss monotropy by citing example of diamond and graphite.
      • 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.)
      • What are the major environmental considerations while treating with the disseminated precious metal mine waste?
  1. PYQs and Practice Questions
  2. UPSC Optionals
  3. Geology Optional
  4. Geology Optional 2025 Paper With Solution
  5. Geology Optional 2025 Paper 2 With Solution

Q 3(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? (UPSC 2025, 15 Marks, 200 Words)

  1. Posted by: Synopsis IAS
  2. Posted on:31 August 2025
Prev
Next
Theme: Albite-Anorthite Phase Diagram and Zoning Interpretation Where in Syllabus: (The subject of the above question is Geology.)
स्वच्छ नामांकित आरेख की सहायता से ऐल्बाइट-ऐनॉर्थांइट का कलीय चित्र (1 वायुमंडलीय दाब, शुष्क) दर्शाइए। एक प्रारंभिक गलित जिसमें Ab20-An80 है, उसके क्रिस्टलीभवन पथ का इस पद्धति में अनुरेखण कीजिए। इस पद्धति में प्लेजिओक्लेस के मंडलन की व्याख्या कैसे की जा सकती है?
Login

Login With Username/password

---------------------- OR ----------------------

Login With OTP

Forget Password

Register

Login (If You are already registered)
Submit

Forget Password

Login/Register

Welcome

Coutinue to Purchase Courses
View Courses
My Courses
View My Purchased Courses
Refer and Earn
© Copyright Synopsis IAS. All Rights Reserved