Q1
Answer the following questions in about 150 words each: (a) Describe the tectonic features and evolution of the 'continental crust'. (10 marks) (b) Describe the physical and chemical weathering processes. (10 marks) (c) Describe the Spatial and Spectral resolution of a remote sensor with examples. (10 marks) (d) Briefly describe the Cataclasite and Pseudotachylite rocks. (10 marks) (e) Discuss the differences between Symmetrical and Asymmetrical folds with the help of neat diagrams. (10 marks)
हिंदी में प्रश्न पढ़ें
निम्नलिखित प्रश्नों में से प्रत्येक का लगभग 150 शब्दों में उत्तर दीजिए : (a) महाद्वीपीय पटल के विवर्तनिक लक्षणों एवं विकास का वर्णन कीजिए । (10 अंक) (b) भौतिक एवं रासायनिक अपक्षय प्रक्रियाओं का वर्णन कीजिए । (10 अंक) (c) सुदूर संवेदी के आकाशीय एवं स्पेक्ट्रमी विभेदन का उदाहरणों सहित वर्णन कीजिए । (10 अंक) (d) उपदलाश्म (कैटाक्लेसाइट) एवं स्यूडोटाचाइलाइट शैलों का संक्षिप्त में वर्णन कीजिए । (10 अंक) (e) स्वच्छ आरेखों की सहायता से सममित एवं असममित वलनों की चर्चा कीजिए । (10 अंक)
Directive word: Describe
This question asks you to describe. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.
See our UPSC directive words guide for a full breakdown of how to respond to each command word.
How this answer will be evaluated
Approach
The directive 'describe' demands systematic, factual exposition with appropriate detail for each sub-part. Allocate approximately 30 words (20%) to part (a) on continental crust evolution, 30 words (20%) to part (b) on weathering processes, 30 words (20%) to part (c) on remote sensing resolutions with specific satellite examples, 30 words (20%) to part (d) on cataclasite and pseudotachylite characteristics, and 30 words (20%) to part (e) on fold geometry with mandatory diagrams. Structure each part as: definition → key characteristics → specific example → significance.
Key points expected
- (a) Continental crust: mention of TTG (tonalite-trondhjemite-granodiorite) composition, crustal differentiation through partial melting, Wilson cycle stages, and comparison with oceanic crust thickness/density
- (b) Weathering: physical processes (exfoliation, frost wedging, salt crystallization) and chemical processes (hydrolysis, oxidation, carbonation, hydration) with at least one example each
- (c) Remote sensing: spatial resolution defined as pixel size (e.g., Landsat-8 OLI: 30m, Sentinel-2: 10m) and spectral resolution as number/wavelength of bands (e.g., hyperspectral vs multispectral)
- (d) Cataclasite: brittle fault rock with angular fragments, low temperature; Pseudotachylite: friction melt, glassy matrix, seismogenic origin, associated with pseudotachylyte generation conditions
- (e) Folds: symmetrical (limbs equal dip, axial plane vertical) vs asymmetrical (limbs unequal dip, axial plane inclined) with proper axial plane and hinge line labeling in diagrams
Evaluation rubric
| Dimension | Weight | Max marks | Excellent | Average | Poor |
|---|---|---|---|---|---|
| Concept correctness | 25% | 12.5 | Precise geological terminology throughout: for (a) correctly identifies TTG suite and crustal growth mechanisms; for (b) distinguishes physical from chemical weathering with correct process definitions; for (c) accurately defines spatial vs spectral resolution without confusion; for (d) correctly differentiates cataclasite (brittle) from pseudotachylite (melt origin); for (e) correctly identifies fold geometry parameters | Generally correct concepts but with minor errors: vague on TTG composition, conflates some weathering types, mixes up resolution definitions, or imprecise on fault rock genesis; fold terminology partially correct | Major conceptual errors: confuses continental and oceanic crust evolution, misclassifies weathering processes, fundamentally misunderstands remote sensing resolutions, cannot distinguish cataclasite from pseudotachylite, or incorrect fold geometry descriptions |
| Diagram / cross-section | 20% | 10 | For part (e), produces two neat, labeled diagrams showing symmetrical fold (vertical axial plane, equal limb dips) and asymmetrical fold (inclined axial plane, unequal limb dips) with hinge line, limbs, and axial plane clearly marked; for (a) may include crustal cross-section; diagrams follow UPSC conventions | One acceptable fold diagram with partial labeling, or two diagrams with minor errors in geometry; missing some key labels like axial plane or hinge line; diagrams present but not neat | Missing diagrams for part (e), or diagrams that misrepresent fold geometry; no attempt at visual representation where required; diagrams without any labels |
| Field evidence | 15% | 7.5 | Cites specific field occurrences: for (a) Archaean cratons of India (Dharwar, Singhbhum); for (b) examples like exfoliation domes at Hyderabad or chemical weathering in laterite belts of Kerala-Karnataka; for (d) mention of pseudotachylite in Main Central Thrust or Coorg region; for (e) fold examples from Himalayan fold-thrust belt or Aravalli | Generic field references without specificity, or only 2-3 parts include field evidence; mentions Indian localities without geological detail | No field evidence cited; entirely theoretical treatment; no Indian examples where clearly applicable |
| Quantitative reasoning | 20% | 10 | Specific numerical data: for (a) continental crust thickness 30-50 km, density 2.7 g/cm³ vs oceanic 7 km/3.0 g/cm³; for (c) precise spatial resolution values (Landsat-8: 30m multispectral, 15m panchromatic; Sentinel-2: 10m) and spectral band numbers; for (e) dip angles and interlimb angles mentioned | Some quantitative data present but imprecise or partially correct; round figures without specificity; only 2-3 parts include numbers | No quantitative data; entirely qualitative descriptions where numbers are standard knowledge; incorrect numerical values stated |
| Indian / economic relevance | 20% | 10 | Strong Indian context: for (a) Indian cratons and crustal evolution; for (b) laterite/bauxite economic deposits from weathering (Gujarat, Odisha); for (c) Indian remote sensing applications (Bhuvan, RISAT, Cartosat for agriculture/mineral exploration); for (d) relevance to understanding Himalayan seismicity; for (e) fold traps in Assam oil fields | Some Indian relevance mentioned but limited to 2-3 parts; generic statements about economic importance without specific Indian examples | No Indian context; no economic significance discussed; entirely generic treatment ignoring India's geological setting and resource base |
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