Geography 2021 Paper I 50 marks Elaborate

Q2

(a) The concept of Plate tectonics has been derived from the isostasy and continental drift theory. Elaborate citing suitable examples. (20 marks) (b) Give a detailed account of bottom topography of the Pacific Ocean. (15 marks) (c) Soil erosion and soil degradation are threat to food supply. Discuss. (15 marks)

हिंदी में प्रश्न पढ़ें

(a) प्लेट विवर्तनिकी की संकल्पना, समस्थिति और महाद्वीपीय अपवाह सिद्धान्त (ड्रिफ्ट थ्योरी) से लिया गया है । उपयुक्त उदाहरण देते हुये विस्तार से बताइये । (20 अंक) (b) प्रशान्त महासागर की तली स्थलाकृति का विस्तार से वर्णन कीजिये । (15 अंक) (c) मृदा अपरदन तथा मृदा निम्नीकरण खाद्य आपूर्ति में खतरा हैं । विवेचना कीजिए । (15 अंक)

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Directive word: Elaborate

This question asks you to elaborate. 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 'elaborate' in part (a) demands detailed explanation with examples, while parts (b) and (c) require 'describe' and 'discuss' respectively. Allocate approximately 40% time/words to part (a) given its 20 marks, and roughly 30% each to parts (b) and (c). Structure: brief introduction linking the three themes (Earth's dynamic surface, ocean floors, and land degradation); systematic treatment of each sub-part with diagrams; conclusion emphasizing integrated Earth system management.

Key points expected

  • Part (a): Explain how isostasy (Airy/Pratt models, crustal buoyancy) and continental drift (Wegener's evidence: fossil fit, paleoclimate, rock continuity) converged into plate tectonics; cite Wilson cycle, sea-floor spreading, and subduction zones
  • Part (a): Examples—East African Rift (divergent), Himalayas (continent-continent collision, isostatic uplift), Mid-Atlantic Ridge; mention GPS validation of plate motions
  • Part (b): Pacific Ocean bottom features—Challenger Deep/Mariana Trench (deepest point), East Pacific Rise, Emperor Seamount chain/Hawaiian hotspot, abyssal plains, guyots, trenches (Kuril, Japan, Peru-Chile), and fracture zones
  • Part (c): Distinguish soil erosion (physical removal) from degradation (chemical, biological, physical deterioration); link to food security via productivity loss, nutrient depletion, and water holding capacity reduction
  • Part (c): Indian examples—ravines of Chambal (gully erosion), black soil degradation in Maharashtra (salinity/alkalinity), lateritic soil exhaustion in Kerala; mention NAP (National Action Plan) on Climate Change, watershed programs, and sustainable land management

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness22%11Demonstrates precise understanding: for (a) distinguishes Airy vs Pratt isostasy and lists Wegener's four evidences correctly; for (b) accurately identifies Challenger Deep depth (~10,984m) and distinguishes trenches from ridges; for (c) clearly differentiates erosion from degradation types (physical/chemical/biological)Shows general familiarity with concepts but confuses isostasy models, omits key Wegener evidences, or treats erosion/degradation synonymously; minor factual errors in ocean depths or trench locationsFundamental misconceptions: conflates isostasy with eustasy, describes Atlantic instead of Pacific features, or fails to distinguish erosion from degradation; significant factual errors
Map / diagram18%9Includes at least three quality diagrams: (a) labeled cross-section of convergent boundary showing isostatic compensation; (b) Pacific Ocean profile with trench-arc-basin system; (c) soil erosion diagram (sheet/rill/gully) or degradation cycle; all properly titled, scaled, and annotatedProvides 1-2 diagrams with basic labeling but missing scales, titles, or key features; or describes features textually without visual representationNo diagrams or extremely poor sketches without labels; fails to utilize visual tools despite explicit geographical content
Indian regional examples20%10Integrates specific Indian examples throughout: for (a) mentions Indian plate movement, Himalayas' isostatic uplift, or Deccan traps mantle plume; for (c) details Chambal ravines, Shivalik erosion, or black soil salinity in Maharashtra with specific locationsMentions generic Indian contexts (Himalayas, Indian plate) without specificity, or lists states without elaborating mechanisms; examples not well-integrated into analysisCompletely omits Indian examples or provides irrelevant/inaccurate ones; treats question as purely theoretical without geographical grounding
Spatial analysis20%10Demonstrates spatial thinking: for (a) maps plate boundaries and their surface expressions; for (b) explains Pacific's asymmetric topography (trenches in west, ridges in east) and ring of fire spatial pattern; for (c) analyzes erosion/degradation spatial patterns (rainfall-erosion relationship, regional soil vulnerability)Describes locations without explaining spatial relationships or patterns; lists features rather than analyzing their distribution and interconnectionNo spatial awareness; random listing without geographical logic; fails to connect processes to their spatial outcomes
Application / policy20%10Connects to practical implications: for (a) mentions earthquake/tsunami prediction, mineral exploration; for (b) notes manganese nodule mining, submarine cable routing; for (c) discusses watershed development (NWDPRA), soil health card scheme, SDG 15.3 on land degradation neutrality, and climate-smart agricultureBrief mention of policies without elaboration; generic statements about 'conservation needed' without specific schemes or their mechanismsNo application or policy discussion; purely academic treatment ignoring real-world relevance and governance responses

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