Geology 2021 Paper I 50 marks Discuss

Q6

(a) Discuss the evolutionary trends in the lineage of equidae and give any two examples of their Indian occurrences. (20 marks) (b) Describe Cenozoic stratigraphy of Kuchh basin. Comment on its fossil content and depositional environment. (15 marks) (c) Discuss briefly as to why artificial recharge is essentially required in confined aquifers. Explain with suitable diagrams a typical injection well for roof-top harvesting of water. (15 marks)

हिंदी में प्रश्न पढ़ें

(a) अश्ववंश के विकासवादी रूझान की चर्चा कीजिए और उनकी भारत में पाये जाने के कोई दो उदाहरण दीजिए । (20 अंक) (b) कच्छ घाटी के नूतन काल की स्तरिकी (सीनोजोइक स्ट्रैटिग्राफी) का वर्णन कीजिए । इसके जीवाश्म अंश और निक्षेपण पर्यावरण पर टिप्पणी कीजिए । (15 अंक) (c) परिरुद्ध जलभृतों में कृत्रिम पुनर्भरण अनिवार्य रूप से क्यों आवश्यक है, संक्षेप में चर्चा करें । छत के जल संचयन के लिये एक विशिष्ट अंतःक्षेपण कूप का उपयुक्त रेखाचित्रों सहित वर्णन कीजिए । (15 अंक)

Evaluate your answer to this question → See all 2021 Geology questions

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 balanced coverage across all three sub-parts. Allocate approximately 40% of time/words to part (a) given its 20 marks, and roughly 30% each to parts (b) and (c). Structure with a brief introduction, then address each sub-part sequentially with clear sub-headings, ensuring diagrams for (a) and (c), and conclude with integrated significance. Secondary directives: 'describe' for (b) requires systematic stratigraphic narration; 'explain' for (c) demands causal reasoning with technical illustration.

Key points expected

  • Part (a): Evolutionary trends in Equidae—Eohippus to Equus showing trends in dentition (hypsodonty, cementum, lophs), limb structure (reduction of digits, elongation of metapodials), and body size; Indian occurrences from Siwalik Hills (Hipparion, Equus) and Dhok Pathan Formation
  • Part (b): Cenozoic stratigraphy of Kutch basin—Eocene (Nummulitic limestone, Kharinadi Formation), Oligocene-Miocene (Khari Nadi, Chhasra formations), Pliocene-Pleistocene (Gaj, Babia Hill formations); fossil content including nummulites, gastropods, vertebrates; depositional environment shifting from shallow marine to fluvial-lacustrine
  • Part (c): Necessity of artificial recharge in confined aquifers—low natural recharge due to impermeable confining layers, declining piezometric levels, prevention of saline water intrusion; injection well design with diagram showing casing, screen, gravel pack, recharge pit, and roof-top collection system with first-flush diversion
  • Integration of evolutionary, stratigraphic, and hydrogeological concepts showing geological continuity from Paleogene to Anthropocene applications
  • Accurate geological nomenclature: Hipparion, Sivalhippus, Pliohippus for equids; Nummulites, Assilina for Kutch; piezometric surface, aquitard, specific yield for hydrogeology

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Demonstrates precise understanding of equid evolutionary trends (orthogenetic vs. adaptive radiation), correct stratigraphic succession in Kutch with formation names and ages, and accurate hydrogeological principles for confined aquifer recharge; uses correct terminology throughout (hypsodonty, lophs, piezometric surface, aquitard)Covers basic evolutionary trends but confuses some genera or stratigraphic order; describes Kutch formations with minor errors in sequence or age; understands confined aquifers but explanation of recharge necessity lacks technical precisionMisrepresents equid evolution (e.g., linear progression without branching), confuses Kutch Cenozoic with Mesozoic stratigraphy, or fundamentally misunderstands confined vs. unconfined aquifer dynamics
Diagram / cross-section20%10Provides two high-quality diagrams: (a) evolutionary lineage of Equidae showing dental and limb modifications with labeled stages (Eohippus, Mesohippus, Merychippus, Pliohippus, Equus); (c) detailed injection well cross-section with roof-top harvesting system, showing casing, screen, gravel pack, recharge chamber, and first-flush mechanismSketches basic equid limb/dental evolution without clear labeling; draws simplified well diagram missing key components like gravel pack or first-flush device; diagrams lack scale or proper annotationOmits diagrams entirely or provides irrelevant sketches; diagrams show fundamental errors (e.g., unconfined aquifer labeled as confined, wrong limb structure in equid evolution)
Field evidence20%10Cites specific Indian localities for equids: Dhok Pathan, Nagri, and Pinjor formations of Siwalik Hills with Hipparion theobaldi and Equus sivalensis; for Kutch, references Bhuj, Lakhpat, and Khavda sections with characteristic fossil assemblages; mentions CGWB or state groundwater reports for confined aquifer depletionMentions Siwalik Hills generally without specific formations; describes Kutch stratigraphy from textbook knowledge without specific section references; cites generic groundwater problems without Indian case examplesNo specific Indian localities mentioned; confuses Kutch with other basins (e.g., Assam, Cauvery); field evidence entirely absent or fabricated
Quantitative reasoning15%7.5Includes approximate time ranges for equid evolution (55 Ma to present), formation thicknesses/ages for Kutch Cenozoic (e.g., Nummulitic limestone ~1000m, Eocene-Oligocene boundary), and quantitative parameters for artificial recharge (injection rates, well spacing, piezometric decline rates in Indian confined aquifers)Mentions broad time periods without precision; gives qualitative description of Kutch stratigraphy thickness; understands artificial recharge need but without quantitative parametersNo numerical data whatsoever; incorrect or grossly inaccurate figures (e.g., equid evolution in millions of years without context, impossible formation thicknesses)
Indian / economic relevance20%10Explicitly connects equid fossils to understanding Siwalik paleoecology and monsoon evolution; links Kutch Cenozoic to hydrocarbon exploration (Cambay Basin analogy) and earthquake geology (2001 Bhuj earthquake); emphasizes artificial recharge for water security in Gujarat's overexploited confined aquifers (e.g., North Gujarat, Saurashtra)Mentions Indian occurrences without broader significance; notes Kutch fossil wealth without economic context; recognizes water scarcity in Gujarat but weak connection to confined aquifer managementTreats question as generic paleontology/stratigraphy/hydrogeology without Indian specificity; no mention of Gujarat's water crisis, hydrocarbon potential, or Siwalik paleoenvironmental significance

Practice this exact question

Write your answer, then get a detailed evaluation from our AI trained on UPSC's answer-writing standards. Free first evaluation — no signup needed to start.

Evaluate my answer →

More from Geology 2021 Paper I