Geology 2022 Paper II 50 marks Discuss

Q8

(a) Give the classification of landslides and discuss the causes of landslide. (20 marks) (b) What is the structure of the Earth ? Is the Earth compositionally homogeneous or composition of the Earth varies with depth ? Write a note on distribution of elements in the Earth. (15 marks) (c) Write the classification of meteorites. Discuss importance of study of meteorites in Earth Science. (15 marks)

हिंदी में प्रश्न पढ़ें

(a) भूस्खलनों का वर्गीकरण दीजिये तथा भूस्खलन के कारणों की विवेचना कीजिये। (20 अंक) (b) पृथ्वी की संरचना क्या है ? क्या पृथ्वी संघटनात्मक रूप से समांगी है या पृथ्वी का संघटन गहराई के साथ बदलता है ? पृथ्वी में तत्वों के वितरण पर एक टिप्पणी लिखिये । (15 अंक) (c) उल्का पिंडों का वर्गीकरण लिखिये । भू-विज्ञान में उल्कापिंडों के अध्ययन के महत्व पर चर्चा कीजिये । (15 अंक)

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Directive word: Discuss

This question asks you to discuss. 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 'discuss' requires critical examination with balanced coverage across all three sub-parts. Allocate approximately 40% of time/words to part (a) given its 20 marks weightage, and 30% each to parts (b) and (c). Structure with brief introductions for each sub-part, systematic classification schemes, causal analysis with Indian examples, and integrated diagrams throughout rather than appended at the end.

Key points expected

  • Part (a): Classification of landslides using Varnes (1978) or Cruden & Varnes system based on material type (rock, debris, earth) and movement mechanism (fall, topple, slide, spread, flow); causes including geological (weak rock, foliation), geomorphological (steep slopes), climatic (rainfall, earthquakes), and anthropogenic factors
  • Part (a): Indian landslide examples—Uttarakhand (Kedarnath 2013), Himachal Pradesh (Kinnaur), Western Ghats (Ambenali ghat), and distinction between shallow and deep-seated failures
  • Part (b): Earth's layered structure—crust (continental vs oceanic), mantle (upper and lower), outer core, inner core with seismic discontinuities (Mohorovičić, Gutenberg, Lehmann)
  • Part (b): Compositional heterogeneity with depth—sial-sima-nife concept or modern chondritic model; distribution of major elements (Fe, O, Si, Mg) and trace elements; siderophile, chalcophile, lithophile element distribution
  • Part (c): Meteorite classification—chondrites (ordinary, carbonaceous, enstatite), achondrites (HED, SNC, lunar), iron and stony-iron meteorites; petrologic types and shock metamorphism
  • Part (c): Importance of meteorite studies—primordial solar system composition, age dating (4.56 Ga), origin of life (organic compounds in carbonaceous chondrites like Murchison), planetary differentiation models, and economic significance (Ni-Fe ores)

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Demonstrates precise understanding of landslide classification schemes (Varnes/Cruden), correctly identifies Earth's compositional layers with seismic evidence, and accurately describes meteorite taxonomy with proper nomenclature; distinguishes between structural and compositional boundaries without conflationCovers basic classification types but confuses some categories (e.g., debris vs earth flows) or oversimplifies Earth's internal structure; mentions meteorite types but lacks systematic hierarchy; minor errors in element distribution conceptsSignificant conceptual errors—misidentifies landslide types, conflates crustal structure with compositional layering, or confuses meteorite classification with asteroid taxonomy; fundamental misunderstanding of Earth's heterogeneity
Diagram / cross-section20%10Includes labeled schematic of landslide types (translational vs rotational), Earth's internal structure cross-section with accurate scale and discontinuity depths, and meteorite classification flowchart; diagrams are neat, properly annotated, and integrated with textProvides at least two relevant diagrams but with incomplete labeling or scale errors; Earth's layers shown but depths approximate; landslide sketches generic without movement arrows; diagrams somewhat disconnected from explanationMissing critical diagrams or poorly executed sketches without labels; diagrams copied without understanding (e.g., showing convection cells without basis); no attempt to illustrate meteorite classification
Field evidence20%10Cites specific Indian landslide case studies with geological context (e.g., Vaiont-type failures in Himalaya, lateritic terrain failures in Western Ghats); references seismic tomography evidence for mantle structure; mentions specific meteorite falls (Nagpur 1868, Shergotty 1865) and finds (Allende, Murchison)Mentions general Himalayan landslide proneness without specific events; acknowledges seismic studies for Earth's structure but no specific references; knows meteorites exist but lacks named examples or fall locationsNo Indian examples for landslides; treats Earth's structure as theoretical without observational basis; completely omits meteorite specimens or confuses with tektites/impactites
Quantitative reasoning15%7.5Provides approximate depths of seismic discontinuities (Moho: 5-70 km, Gutenberg: ~2900 km, Lehmann: ~5150 km); mentions Earth's mass distribution percentages; includes slope angle thresholds for landslide initiation; cites meteorite age (4.56 Ga) and compositional percentagesRough depth estimates for Earth's layers without precision; qualitative discussion of slope stability without angle values; knows meteorites are old but no specific datingNo quantitative data whatsoever; incorrect orders of magnitude for depths or ages; confuses units (km vs miles) or percentages
Indian / economic relevance20%10Discusses GSI landslide zonation mapping, NHPC and hydropower project vulnerabilities in Himalaya; links meteorite studies to India's planetary exploration (Chandrayaan, Mars Orbiter Mission) and potential asteroid mining; mentions nickel-iron meteorite economic analogs to Sudbury-type depositsAcknowledges landslide hazard in India without specific agencies or policies; mentions ISRO missions but weak connection to meteorite science; superficial economic relevanceNo Indian context for any sub-part; misses opportunity to connect meteorite composition to Earth's core formation or domestic mineral exploration

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