Q6
(a) Elucidate the evolutionary trend of Proboscidea with examples. (20 marks) (b) Describe lithostratigraphic classification and shift of depositional environments during deposition of the Vindhyan Supergroup. Comment on the age of the Vindhyan succession. (15 marks) (c) Describe briefly the characteristics of different types of aquifers and also discuss the important properties that an aquifer should possess. (15 marks)
हिंदी में प्रश्न पढ़ें
(a) उदाहरण के साथ प्रोबोसिडिया की विकासवादी प्रवृत्ति को स्पष्ट कीजिए। (20 अंक) (b) विंध्यन सुपरग्रुप के निक्षेपण के दौरान अश्म-स्तरीय वर्गीकरण और निक्षेपण वातावरण में बदलाव का वर्णन कीजिए। विंध्यन अनुक्रम काल पर टिप्पणी कीजिए। (15 अंक) (c) विभिन्न प्रकार के जलभृत की विशेषताओं का संक्षेप में वर्णन कीजिए तथा जलभृत के धारण-योग्य प्रमुख गुणों का भी उल्लेख कीजिए। (15 अंक)
Directive word: Elucidate
This question asks you to elucidate. 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 'elucidate' demands clear, illuminating explanation with examples. Structure: Introduction (2-3 lines) → Part (a) Proboscidea evolution (~40% word budget, 20 marks) with morphological trends and Indian examples → Part (b) Vindhyan stratigraphy (~30%, 15 marks) covering lithostratigraphy, facies changes, and age controversy → Part (c) Aquifer types and properties (~30%, 15 marks) → Brief conclusion. Use diagrams for (a) and (b).
Key points expected
- (a) Proboscidea: Moeritherium → Deinotherium → Gomphotherium → Elephas/Mammuthus lineage; key trends—trunk elongation, tusks from incisors to upper/lower, molar hypsodonty, loss of premolars; Indian examples: Stegodon, Elephas hysudricus from Siwaliks, Palaeoloxodon from Hathnora
- (a) Adaptive significance: feeding height stratification, aquatic to terrestrial transition, climate-driven selection during Cenozoic
- (b) Vindhyan lithostratigraphy: Lower Vindhyan (Semri Group: Kajrahat Limestone, Porcellanite) vs Upper Vindhyan (Kaimur, Rewa, Bhander groups); unconformity and basin inversion
- (b) Depositional shift: shallow marine/carbonate ramp (Semri) → fluvial-deltaic-lacustrine (Kaimur-Rewa) → aeolian-ephemeral lake (Bhander); age debate: Mesoproterozoic (Rb-Sr) vs Neoproterozoic (C-isotope, Ediacaran fossils)
- (c) Aquifer types: unconfined (water table), confined (artesian), semi-confined/leaky; perched aquifers; examples: Bhabhar zone (unconfined), Ganga-Yamuna doab (confined)
- (c) Essential properties: porosity, permeability (hydraulic conductivity), specific yield, storage coefficient, transmissivity; Darcy's law application; aquifer vulnerability to contamination
Evaluation rubric
| Dimension | Weight | Max marks | Excellent | Average | Poor |
|---|---|---|---|---|---|
| Concept correctness | 25% | 12.5 | Accurately traces Proboscidea phylogeny with correct stratigraphic ranges; precisely defines Vindhyan groups with correct lithologies and sequence; correctly distinguishes aquifer types with proper hydrogeological terminology; no anachronisms in fossil ranges | Broadly correct lineage for Proboscidea but misses key transitions; knows Vindhyan divisions but confuses lithologies or sequence; defines aquifer types but conflates porosity/permeability or omits storage coefficient | Confuses Proboscidea with Sirenia or other orders; garbled Vindhyan stratigraphy with wrong group order; fundamental errors in aquifer classification (e.g., calling all groundwater 'underground river') |
| Diagram / cross-section | 20% | 10 | Sketches clear Proboscidea skull/molar evolution diagram; draws labeled Vindhyan lithostratigraphic column with facies transitions; illustrates confined vs unconfined aquifer cross-section with potentiometric surface; diagrams enhance explanation | Attempts diagrams for two parts but lacks labels or scale; OR describes diagrams in text without visual representation; basic stratigraphic column without environmental indicators | No diagrams despite clear need; OR irrelevant diagrams; messy unlabeled sketches that confuse rather than clarify |
| Field evidence | 20% | 10 | Cites specific Indian localities: Hathnora hominid site with Elephas, Narmada valley proboscidean fossils, Sonia Vindhyan exposures, Ganga basin aquifer studies; mentions actual fossil specimens or borehole data | Mentions 'Siwaliks' or 'Vindhyan hills' generically; knows Ganga aquifer exists but no specific field data; broad regional references without site specificity | No Indian field evidence; OR invents non-existent localities; confuses Vindhyan with other basins (Cuddapah, Chhattisgarh) |
| Quantitative reasoning | 15% | 7.5 | Uses approximate ages for Proboscidea stages (Eocene-Pleistocene); cites Vindhyan age ranges (~1600-540 Ma with uncertainty); applies Darcy's law or gives typical hydraulic conductivity values for aquifer types; mentions isotopic dating methods | Knows relative ages (older to younger) without numbers; mentions 'Proterozoic' for Vindhyan; qualitative description of aquifer flow without parameters | No quantitative elements where appropriate; grossly wrong ages; confuses hydraulic head with water depth |
| Indian / economic relevance | 20% | 10 | Links Proboscidea to Indian elephant ancestry and conservation genetics; discusses Vindhyan building stones (Mirzapur sandstone, Rewa porcellanite) and diamond potential (Panna); emphasizes groundwater security for Indo-Gangetic agriculture and urban water stress | Mentions Indian elephant as descendant; notes Vindhyan as 'important rock sequence'; states groundwater 'important for India' without elaboration | Treats as purely academic exercise; no Indian context; or irrelevant economic links |
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