Geology 2021 Paper I 50 marks 150 words Compulsory Discuss

Q5

Answer the following questions in about 150 words each: (a) What are megafossils? Give names of any three age-diagnostic megafossils indicating their significance in Indian stratigraphy. (10 marks) (b) What is paleogeography? Discuss various tools employed in paleogeographic reconstruction. (10 marks) (c) Define lithostratigraphy. Enlist diagnostic properties of lithostratigraphic units giving example from Indian stratigraphy. (10 marks) (d) Discuss characteristics of confined and unconfined aquifers. (10 marks) (e) Discuss briefly characteristics of earthquake resistant structures. (10 marks)

हिंदी में प्रश्न पढ़ें

निम्नलिखित प्रत्येक प्रश्न का उत्तर लगभग 150 शब्दों में दीजिए । (a) महाजीवाश्म क्या हैं ? किन्हीं तीन आयु सूचक महाजीवाश्मों के नाम दीजिए तथा भारतीय स्तरिकी में उनका महत्व रेखांकित कीजिए । (10 अंक) (b) पुराभूगोल क्या है ? पुराभौगोलिक पुनर्निर्माण में नियोजित विभिन्न उपकरणों की चर्चा कीजिए । (10 अंक) (c) अश्मस्तरिकी (लिथोस्ट्रैटिग्राफी) को परिभाषित कीजिए । अश्मस्तरिक एकक के लक्षणिक गुणों को सूचीबद्ध कर उनके भारतीय स्तरिकी में उदाहरण दें । (10 अंक) (d) परिरुद्ध और अपरिरुद्ध जलभृतों की विशेषताओं पर चर्चा कीजिए । (10 अंक) (e) भूकंपरोधी संरचनाओं की विशेषताओं पर संक्षेप में चर्चा कीजिए । (10 अंक)

Directive word: Discuss

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How this answer will be evaluated

Approach

This multi-part question requires approximately 150 words per sub-part (30 words per mark). Begin with concise definitions for (a), (c) and operational descriptions for (b), (d), (e). Allocate roughly equal time (~6 minutes) per sub-part. For (a), define megafossils then cite three Indian examples with stratigraphic significance. For (b), define paleogeography then enumerate reconstruction tools with brief elaboration. For (c), define lithostratigraphy, list diagnostic properties, and illustrate with Indian formation. For (d), compare confined and unconfined aquifers through tabular or point-wise contrast. For (e), outline seismic design principles with structural characteristics. No conclusion needed; maximize content density within word limits.

Key points expected

  • (a) Megafossils definition: macroscopic remains visible to naked eye; three Indian examples with age significance—e.g., Siwalik vertebrates (Neogene-Quaternary), Gondwana Glossopteris (Permian), Cretaceous Inoceramus (marine transgression markers)
  • (b) Paleogeography definition: ancient geographic conditions; tools—paleomagnetism, facies analysis, biofacies/paleoecology, paleoclimatic indicators, paleogeographic maps, computer modeling, sea-level curves
  • (c) Lithostratigraphy definition: rock-based stratigraphic classification; diagnostic properties—lithology, color, texture, mineralogy, bedding characteristics, fossil content, thickness; Indian example—Vindhyan Supergroup (Sandstone-Shale-Limestone sequence)
  • (d) Confined aquifer: overlain by aquiclude, under artesian pressure, potentiometric surface, regional extent, steady yield; Unconfined aquifer: water table exposed to atmosphere, direct recharge, seasonal fluctuation, phreatic surface, local extent
  • (e) Earthquake resistant structures: base isolation, ductile detailing, shear walls, moment-resisting frames, tuned mass dampers, regular plan/elevation, soft storey avoidance, IS 1893 compliance

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Precise definitions across all sub-parts: megafossils distinguished from microfossils; paleogeography differentiated from paleoclimatology; lithostratigraphy distinguished from chronostratigraphy; accurate aquifer hydraulics; correct seismic engineering terminology per IS codesGenerally correct definitions with minor errors—e.g., conflating lithostratigraphy with biostratigraphy, or vague aquifer distinctions without hydraulic head explanationFundamental conceptual errors—e.g., defining megafossils simply as 'large fossils' without size threshold, or confusing confined/unconfined aquifers completely
Diagram / cross-section15%7.5For (d): labeled cross-section showing confined aquifer with aquiclude, artesian well, potentiometric surface vs. unconfined with water table and perched aquifer; for (e): simple shear wall/base isolation sketch; diagrams enhance clarity despite word constraintsBasic unlabeled sketch of aquifer types or generic building frame without specific seismic features; diagrams present but incompleteNo diagrams where essential (aquifer comparison), or irrelevant/illegible sketches that confuse rather than clarify
Field evidence20%10Specific Indian field localities: for (a)—Siwalik fossils from Haritalyangar, Gondwana from Damodar valley, Inoceramus from Uttatur Group; for (c)—Vindhyan exposure at Chitrakoot or Son valley; demonstrates actual stratigraphic applicationGeneric Indian references without specific localities—e.g., 'Siwalik hills' without Haritalyangar, or 'Vindhyan basin' without outcrop mentionNo Indian field evidence, or invented/locality errors—e.g., placing Gondwana fossils in Himalayas or confusing stratigraphic horizons
Quantitative reasoning15%7.5Numerical aspects where applicable: hydraulic head/pressure relationships in confined aquifers; approximate depth ranges for Indian formations (e.g., Vindhyan ~4500m thick); seismic zone parameters (Zone V PGA values); porosity/permeability contrastsQualitative treatment of quantitative concepts—mentions 'pressure' or 'depth' without values, or 'high porosity' without comparisonEntirely qualitative despite quantitative opportunities; no mention of hydraulic gradients, formation thicknesses, or seismic coefficients
Indian / economic relevance25%12.5Strong Indian stratigraphic integration: GSI classification systems, IS 1893 seismic zones applied to Himalayan/peninsular contexts, groundwater exploitation in Indo-Gangetic confined aquifers vs. Deccan Trap unconfined aquifers, economic significance of Vindhyan building stones, Siwalik paleoclimate proxies for monsoon evolutionSome Indian examples present but underdeveloped—lists formations without economic/stratigraphic significance, or generic seismic design without Indian code contextWestern-centric or generic examples only—e.g., citing Burgess Shale for megafossils, or San Andreas fault for seismic design with no Indian application

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