Q6
(a) Discuss the evolutionary lineage of Equidae and comment on its migration. (20 marks) (b) Give the lithostratigraphic classification and distribution of Delhi Supergroup. Also comment on the economic significance of this supergroup. (15 marks) (c) What are different type of wells used for the extraction of groundwater ? How and why the well field should be protected ? (15 marks)
हिंदी में प्रश्न पढ़ें
(a) इक्वीडी की क्रम विकास पंक्ति-बद्धता तथा उसके प्रवसन का वर्णन कीजिए । (20 अंक) (b) दिल्ली महासमूह का शैल स्तरीय वर्गीकरण एवं वितरण का उल्लेख कीजिए । इस महासमूह की आर्थिक सार्थकता पर प्रकाश डालिए । (15 अंक) (c) भूजल की निकासी के लिये कौन से विभिन्न प्रकार के कुएं होते हैं । कूप क्षेत्र का संरक्षण कैसे और क्यों किया जाना चाहिये । (15 अंक)
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' demands a comprehensive, analytical treatment with critical commentary. Allocate approximately 40% of time/words to part (a) given its 20 marks, covering Eocene-Oligocene-Miocene-Pliocene-Pleistocene transitions with migration routes; 30% each to parts (b) and (c). Structure: brief introduction → systematic treatment of each sub-part with diagrams → integrated conclusion linking evolutionary adaptation, stratigraphic correlation, and sustainable resource management.
Key points expected
- Part (a): Eohippus (Hyracotherium) to Equus lineage showing dental evolution (low-crowned brachydont to high-crowned hypsodont), limb reduction from 4-toed to 1-toed, and size increase; migration via Bering land bridge to Old World and Siwalik fossil record (Gandak, Nepal)
- Part (a): Cope's Law and adaptive significance of cursorial locomotion; mention of Hipparion dispersal and stenonine zebras; Indian context: Equus sivalensis and Equus namadicus from Pinjor stage
- Part (b): Delhi Supergroup classification into Alwar Group (older, arenaceous) and Ajabgarh Group (younger, calcareous-arenaceous); distribution in Delhi-Aravalli fold belt (Alwar, Jaipur, Ajmer, Delhi)
- Part (b): Economic significance: Rajpura-Dariba and Zawar lead-zinc deposits, Khetri copper belt, Rampura-Agucha zinc-lead-silver, decorative stones (Alwar quartzite), groundwater aquifers in fractured quartzites
- Part (c): Well types: dug wells, tube wells (shallow/deep), artesian wells, infiltration galleries, radial collector wells; selection criteria based on aquifer type (unconfined/confined), depth, and discharge requirements
- Part (c): Well field protection: sanitary seals, setback distances from contamination sources (30m for septic tanks), groundwater zoning, artificial recharge structures; rationale for preventing cone of depression interference and saline water intrusion in coastal aquifers
Evaluation rubric
| Dimension | Weight | Max marks | Excellent | Average | Poor |
|---|---|---|---|---|---|
| Concept correctness | 25% | 12.5 | Precisely identifies all stratigraphic units of Delhi Supergroup (Raialo, Alwar, Ajabgarh with correct sequence); accurately traces Equidae through Hyracotherium-Mesohippus-Merychippus-Pliohippus-Equus with correct temporal ranges (Eocene to Pleistocene); correctly classifies well types by construction and hydrogeological applicability; distinguishes between confined and unconfined aquifer well designs | Identifies major groups but confuses Alwar-Ajabgarh sequence or omits Raialo; mentions key Equidae genera but with incorrect chronological order or missing dental/limb adaptations; lists well types without hydrogeological basis; vague on well field protection principles | Confuses Delhi Supergroup with Aravalli Supergroup; equates Equidae evolution with random mutation rather than adaptive radiation; conflates dug wells with tube wells; omits sanitary protection or cites irrelevant criteria |
| Diagram / cross-section | 20% | 10 | Draws evolutionary lineage diagram showing dental patterns (brachydont→mesodont→hypsodont), limb structure evolution, and size progression; sketches Delhi fold belt cross-section showing Alwar-Ajabgarh relationship and mineralized zones; illustrates well construction with proper casing, screen placement, and gravel pack for different aquifer types | Provides generic stratigraphic column without tectonic context; simple linear evolutionary diagram without anatomical detail; basic well schematic missing critical components like sanitary seal or pump placement | No diagrams or irrelevant sketches; diagrams with major errors (e.g., reversed stratigraphy, anatomically incorrect limb evolution, well screen in impermeable layer) |
| Field evidence | 20% | 10 | Cites specific Siwalik localities (Chandigarh, Haritalyangar, Gandak) for Equus fossils; references GSI mapping of Delhi Supergroup in Khetri-Alwar belt; mentions CGWB well inventory data or specific well fields (e.g., Mehsana, Chennai aquifer management); correlates lithology with fossil preservation potential | General reference to 'Siwalik hills' without specific fossil sites; mentions Delhi belt minerals without locating specific mines; generic reference to 'tubewells in Punjab/Haryana' without field context | No field evidence cited; confuses Siwalik fossils with Vindhyan or Gondwana assemblages; cites non-existent well fields or incorrect mineral associations |
| Quantitative reasoning | 15% | 7.5 | Provides approximate time ranges for Equidae stages (e.g., Merychippus ~15-5 Ma); estimates Delhi Supergroup thickness (~3000-7000m); calculates well spacing based on radius of influence (e.g., 150-300m for medium tubewells); mentions specific discharge rates or drawdown limits for sustainable yield | Rough chronological ordering without numerical ages; mentions 'thick sequence' without quantitative estimate; qualitative discussion of well spacing without calculation basis | No quantitative data; grossly incorrect figures (e.g., Delhi Supergroup as Archean, Equus in Cretaceous); confuses well diameter with yield relationships |
| Indian / economic relevance | 20% | 10 | Links Equidae evolution to Siwalik biostratigraphy and Himalayan uplift chronology; emphasizes Delhi Supergroup as India's largest base metal province (Zawar, Khetri, Rajpura-Dariba) and strategic mineral security; connects well field protection to India's groundwater crisis (decreasing water table in Punjab, Haryana, Rajasthan) and Atal Bhujal Yojana objectives | Mentions Indian localities in passing; notes 'economic minerals' without specific commodities or national significance; generic reference to water scarcity without policy context | Treats question as purely academic with no Indian context; omits economic significance entirely; discusses foreign well field examples exclusively |
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