All 8 questions from UPSC Civil Services Mains Geology
2025 Paper I (400 marks total). Every stem reproduced in full,
with directive-word analysis, marks, word limits, and answer-approach pointers.
Answer the following questions in about 150 words each:
(a) Discuss the position of Astroid belt within the solar system and comment on the composition of meteorites. (10 marks)
(b) What are sheath folds ? Discuss the deformational conditions of their formation. (10 marks)
(c) What is Global Positioning System (GPS) ? Explain its geological applications. (10 marks)
(d) Discuss the statement giving suitable examples. "Physical weathering adds to the effectiveness of Chemical weathering". (10 marks)
(e) Discuss the types of Penetrative and Non-penetrative lineations with the help of suitable diagrams and throw light on their genesis. (10 marks)
हिंदी में पढ़ें
निम्नलिखित प्रश्नों में से प्रत्येक का लगभग 150 शब्दों में उत्तर दीजिए :
(a) सौर्य मण्डल में क्षुद्रग्रहीय पट्टी की स्थिति तथा उल्कापिंडों के संघटन का वर्णन कीजिए । (10 अंक)
(b) शीथ वलन क्या होते हैं ? इनकी उत्पत्ति की विरूपण अवस्था की विवेचना कीजिए । (10 अंक)
(c) ग्लोबल पोजिशनिंग सिस्टम (जी. पी. एस.) क्या है ? इसके भूवैज्ञानिक उपयोगों को समझाइये । (10 अंक)
(d) "भौतिक अपक्षय रासायनिक अपक्षय की क्षमता को बढ़ाता है" । इस कथन की उचित उदाहरणों द्वारा विवेचना कीजिए । (10 अंक)
(e) उचित आरेखों की सहायता से विभिन्न प्रकार के भेदक तथा गैर-भेदी सरेखण की विवेचना कीजिये तथा इनकी उत्पत्ति पर प्रकाश डालिये । (10 अंक)
Answer approach & key points
The directive 'discuss' demands a balanced, analytical treatment across all five parts with clear reasoning and examples. Allocate approximately 30 words (20% time) per sub-part: (a) locate asteroid belt between Mars-Jupiter with Kirkwood gaps and meteorite classes; (b) define sheath folds with hinge rotation and high strain conditions; (c) GPS satellite configuration with crustal deformation monitoring; (d) synergistic weathering with Indian examples like exfoliation aiding lateritization; (e) contrast penetrative (S1 foliation, L1 lineation) vs non-penetrative (crenulation, millions) lineations with genesis. Prioritize diagrams for (b) and (e) where structural visualization is essential.
(a) Asteroid belt position: 2.1-3.3 AU between Mars (1.5 AU) and Jupiter (5.2 AU); Kirkwood gaps resonant with Jupiter; meteorite composition: chondrites (primitive), achondrites (differentiated), iron-stony-iron; carbonaceous chondrites and amino acids significance
(b) Sheath folds: highly non-cylindrical folds with curved hinge lines in XZ plane of strain ellipsoid; type 3 interference patterns; formation in high shear strain zones (>γ=10), non-coaxial deformation, mylonitic zones
(a) What do you understand by continental drift ? Discuss various geological evidences in favour of continental drift. (20 marks)
(b) Geomorphic diversity is controlled by a number of endogenic and exogenic processes. Discuss this statement. (15 marks)
(c) Describe morphotectonic features characteristic of rejuvenation in a mountaineous terrain. (15 marks)
हिंदी में पढ़ें
(a) महाद्वीपीय विस्थापन से आप क्या समझते हैं ? महाद्वीपीय विस्थापन के विभिन्न भूवैज्ञानिक साक्ष्यों का वर्णन कीजिये । (20 अंक)
(b) भू-आकृति विविधता विभिन्न अंतर्जनित तथा बहिर्जनित क्रियाओं से नियंत्रित होती है । इस कथन की विवेचना कीजिए । (15 अंक)
(c) पर्वतीय भूभाग में पुनर्युवन संलक्षणी विवर्तनिक भूआकृतियों का वर्णन कीजिये । (15 अंक)
Answer approach & key points
The directive 'discuss' demands a balanced, analytical treatment with evidence-based reasoning across all three parts. Allocate approximately 40% of time/words to part (a) given its 20 marks, and roughly 30% each to parts (b) and (c). Structure: brief integrated introduction → systematic treatment of (a) Wegener's hypothesis with evidences, (b) process-driven geomorphic diversity with Indian examples, (c) rejuvenation landforms with Himalayan/Deccan references → synthesizing conclusion on dynamic Earth processes.
Part (a): Wegener's continental drift hypothesis (1912), palaeomagnetic evidence, matching coastlines (Africa-South America), fossil correlations (Glossopteris, Mesosaurus), rock type and structural continuity (Appalachian-Caledonian belt), palaeoclimatic evidence (tillites in India/Africa/Australia)
Part (b): Endogenic controls (tectonics, volcanism, isostasy) and exogenic controls (weathering, erosion, deposition, climate) on landform diversity; specific Indian examples like Western Ghats escarpment, Meghalaya plateau, Thar dunes
Part (c): Rejuvenation concepts (Davisian cycles, epeirogenic uplift); morphotectonic features including incised meanders, river terraces, knickpoints, uplifted peneplains, antecedent/superimposed drainage; Indian examples from Himalayas (Siulik, Dun valleys) or Western Ghats
Integration: Link drift to geomorphic diversity through plate tectonics framework; connect rejuvenation to ongoing Himalayan orogeny
Critical perspective: Limitations of continental drift (lacking mechanism) superseded by plate tectonics; modern understanding of isostatic vs. tectonic uplift
50MjustifyCoastal geomorphology, remote sensing and GIS, thrust geometries
(a) Waves are responsible for modifying the coastal geomorphology. Justify the statement giving suitable examples and neat diagrams. (20 marks)
(b) Explain how the Remote Sensing and Geographic Information System (GIS) may help in delineation of Groundwater potential zone ? (15 marks)
(c) Using neat sketches describe various types of Thrust geometries formed in a compressional regime. (15 marks)
हिंदी में पढ़ें
(a) तरंगे तटीय भूआकृतियों को रूपांतरित करने के लिए उत्तरदायी हैं । तर्कसंगत उदाहरण एवं स्पष्ट चित्रों की सहायता से कथन की व्याख्या कीजिये । (20 अंक)
(b) सुदूर संवेदन तथा भौगोलिक सूचना प्रणाली (जी. आई. एस.) किस प्रकार भूजल संभाव्य क्षेत्र के अंकन में सहायक हो सकते हैं ? (15 अंक)
(c) स्पष्ट चित्रों की सहायता से संपीड़नीय व्यवस्था में बने विभिन्न प्रकार की क्षेपभ्रंश ज्यामिति का वर्णन कीजिये । (15 अंक)
Answer approach & key points
The directive 'justify' in part (a) demands evidence-based argumentation with cause-effect reasoning, while parts (b) and (c) require 'explain' and 'describe' respectively. 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 integrated introduction, then three clearly demarcated sections addressing each sub-part sequentially, using diagrams strategically within each section rather than as an afterthought.
Part (a): Wave mechanics (constructive vs destructive waves), wave refraction and longshore drift, erosional landforms (wave-cut platforms, stacks, arches, caves), depositional landforms (spits, bars, tombolos, beaches), with Indian examples like Chhera Dwip in Bangladesh/India, Marina Beach, or Kerala backshore barriers
Part (b): RS data sources (Landsat, Sentinel, ASTER) for lithology, lineament and drainage mapping; GIS overlay analysis of slope, soil, drainage density, rainfall, land use; integration of thematic layers for groundwater potential index (GWP); validation through well yield data
Part (c): Thrust fault geometry classification—imbricate fan, duplex structure (antiformal stack), triangle zone, passive roof duplex, and foreland-vergent vs hinterland-vergent systems; stress orientations and fault-bend/fault-propagation folding relationships
Cross-cutting application: Integration of geomorphic process understanding with modern analytical tools (RS/GIS) and structural geometry, demonstrating how surface processes, technology, and tectonics interconnect in geological studies
Diagrammatic requirements: Wave approach and refraction diagrams, coastal landform sketches, RS/GIS workflow schematic, thrust geometry cross-sections with displacement vectors and stress ellipses
(a) On the basis of dip isogons describe the classification of folds with neat diagrams. (20 marks)
(b) What are volcanoes ? Describe various causes and products of volcanism. (15 marks)
(c) How does strain analysis help in understanding the nature of rock deformation. Discuss centre to centre method of estimation of two dimensional strain. (15 marks)
हिंदी में पढ़ें
(a) समनति रेखा के आधार पर वलन वर्गीकरण का सचित्र वर्णन कीजिए । (20 अंक)
(b) ज्वालामुखी क्या है ? ज्वालामुखी उद्भव के विभिन्न कारणों तथा उत्पादों का वर्णन कीजिये । (15 अंक)
(c) विकृति विश्लेषण किस प्रकार शैल विक्षेपण की प्रकृति को समझने में मदद करता है । द्विआयामी विकृति का आकलन करने के लिये केन्द्र से केन्द्र विधि की विवेचना कीजिये । (15 अंक)
Answer approach & key points
The directive 'describe' demands systematic, detailed exposition with visual support. Allocate approximately 40% of time/words to part (a) given its 20 marks weightage, with ~30% each to parts (b) and (c). Structure: brief introduction defining folds, volcanoes and strain; detailed body addressing each sub-part sequentially with diagrams for (a) and (c); concluding synthesis on how these tools decode Earth's deformation history.
Part (a): Definition of dip isogons; Ramsay's classification into Class 1A (strongly convergent), 1B (parallel/thickening), 1C (weakly convergent), 2 (similar), 3 (strongly divergent) with layer thickness variations
Part (a): Tangent diagram method and relationship between dip isogon geometry and fold mechanism (flexural slip vs. pure shear)
Part (b): Definition of volcano; causes—mantle plumes, subduction, rifting, hotspot volcanism; products—lava flows, pyroclastics, volcanic gases, intrusions
50M150wCompulsorydiscussFossilization, biozonation, Blaini Boulder Bed, building stones, water types
Answer the following questions in about 150 words each:
(a) Discuss favourable conditions for fossilization. (10 marks)
(b) Discuss different concepts of biozonation with neat diagrams. (10 marks)
(c) Describe the lithology, type locality, age and depositional environment of Blaini Boulder Bed. (10 marks)
(d) What engineering properties make Marble, Sandstone and Granite useful as building stone ? (10 marks)
(e) Explain different generic type of water and their significance in water supply. (10 marks)
हिंदी में पढ़ें
निम्नलिखित प्रश्नों में से प्रत्येक का लगभग 150 शब्दों में उत्तर दीजिये :
(a) जीवाश्मन के लिये अनुकूल परिस्थितियों का वर्णन कीजिए । (10 अंक)
(b) जैव मंडलन की विभिन्न अवधारणाओं का सचित्र वर्णन कीजिए । (10 अंक)
(c) ब्लैनी गोलाश्म-संस्तर के शैललक्षण, प्रतीकात्मक क्षेत्र, आयु तथा निक्षेपण पर्यावरण का वर्णन कीजिये । (10 अंक)
(d) संगमरमर, बलुआपथर तथा ग्रेनाइट के कौन से अभियांत्रिकी गुण उनको इमारती पत्थर के लिये उपयोगी बनाते हैं ? (10 अंक)
(e) जल की विभिन्न जनित प्रकार तथा उनकी जल आपूर्ति में सार्थकता पर प्रकाश डालिए । (10 अंक)
Answer approach & key points
The directive 'discuss' demands a balanced, analytical treatment across all five sub-parts. Allocate approximately 30 words (20% time) per sub-part, with slightly more emphasis on (b) biozonation due to its diagram requirement and (c) Blaini Boulder Bed due to its multi-component factual demand. Structure each sub-part as: brief introduction → systematic coverage of all directive components → concluding significance statement. For (b), reserve space for two labeled diagrams; for (d), use comparative tabular format.
(a) Fossilization: Rapid burial, possession of hard parts, anaerobic environment, absence of diagenetic dissolution, and examples from Siwalik or Vindhyan fossils
(b) Biozonation: Range zone, Assemblage zone, Acme zone, Oppel zone concepts with stratigraphic range diagrams showing overlapping species distributions
(c) Blaini Boulder Bed: Purple/green shale matrix with exotic clasts, Blaini village (Mussoorie), Lower Cambrian, glacial-marine dropstone environment of Marinoan glaciation equivalent
(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 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)
Answer approach & key points
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.
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
(a) What do you understand by boundary problems in stratigraphy ? Discuss Cretaceous/Palaeogene (Cretaceous/Tertiary) boundary problem giving Indian examples. (20 marks)
(b) What are the important groups of microfossils ? Add notes on their composition and significance. (15 marks)
(c) Why Earthquake resistant structures are needed ? Discuss the geological considerations required for developing the Earthquake resistant structures. (15 marks)
हिंदी में पढ़ें
(a) स्तरक्रमविज्ञान में परिसीमा समस्या से आप क्या समझते हैं ? क्रिटेशियस/पैलियोसीन (क्रिटेशियस/टर्सियरी) परिसीमा समस्या का भारतीय उदाहरणों सहित वर्णन कीजिए । (20 अंक)
(b) सूक्ष्म जीवाश्म के मुख्य समूह क्या होते हैं ? उनकी संरचना और महत्ता पर टिप्पणी कीजिये । (15 अंक)
(c) भूकंपीय प्रतिरोधक संरचनाएँ क्यों आवश्यक हैं ? भूकंपीय प्रतिरोधक संरचनाओं को विकसित करने के लिये आवश्यक भूवैज्ञानिक अनुचिंतन पर चर्चा कीजिये । (15 अंक)
Answer approach & key points
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 30% each to parts (b) and (c). Structure: brief introduction defining stratigraphic boundaries → detailed treatment of K/Pg boundary with Indian evidence → systematic coverage of microfossil groups with composition tables → analysis of seismic zoning and geological considerations for earthquake-resistant design → concluding synthesis on applied stratigraphy and hazard mitigation.
Part (a): Definition of boundary problems (unconformities, hiatuses, biostratigraphic gaps) and specific K/Pg boundary characteristics including iridium anomaly, shocked quartz, and mass extinction event
Part (a): Indian K/Pg boundary evidence from Um Sohryngkew River section (Meghalaya), Anjar intertrappean beds (Kutch), and Rajahmundry traps with their geological and paleontological signatures
Part (b): Major microfossil groups—Foraminifera (calcareous), Radiolaria (siliceous), Ostracoda (calcareous), Diatoms (siliceous), and their wall composition (test structure, mineralogy)
Part (b): Biostratigraphic, paleoecological, and economic significance of microfossils in petroleum exploration, paleoclimatic reconstruction, and age correlation
Part (c): Seismic zoning of India (Zone V to II), liquefaction potential, and site-specific geological considerations (soil type, bedrock depth, fault proximity)
Part (c): Engineering-geological parameters for earthquake-resistant design including shear wave velocity, bearing capacity, and foundation recommendations for different geological settings
(a) Discuss the interrelationship amongst Porosity, Permeability and Hydraulic conductivity. How they are important in groundwater movement ?
A sediment sample with a cross section area of 0.02 m² is tested in a permeameter with a length of 30 cm. Water flows through the sample at a rate of 0.08 m³/sec with a head difference (h₁ – h₂) 20 cm. Calculate the Hydraulic conductivity. (20 marks)
(b) Describe important Lower Gondwana plant fossils with the help of neat diagrams and comment on their palaeobiogeographic significance. (15 marks)
(c) Discuss the lithology, fossil content and age of palaeozoic sequence of Spiti Basin of Himachal Pradesh. (15 marks)
हिंदी में पढ़ें
(a) संरंधता, पारगम्यता और जलीय चालकता के अन्तर सम्बन्धों पर चर्चा कीजिये । भूजल संचलन के लिये यह किस प्रकार महत्त्वपूर्ण है ?
0.02 वर्ग मीटर अनुप्रस्थीय क्षेत्र तथा 30 से.मी. लम्बाई वाले परमीयमीटर में अवसादी नमूने को जाँचा गया । नमूने से होकर 0.08 घनमीटर प्रति सेकंड की दर से तथा शीर्षान्तर 20 से.मी. (h₁ – h₂) के साथ जल प्रवाहित होता है । नमूने की जलीय चालकता की गणना कीजिये । (20 अंक)
(b) स्पष्ट चित्रों की सहायता से निम्न गोंडवाना के मुख्य वनस्पति जीवाश्मों का वर्णन कीजिये तथा उनकी पुराजीव भौगोलिक महत्ता पर टिप्पणी लिखिए । (15 अंक)
(c) हिमाचल प्रदेश की स्पिति घाटी में पैलियोजोइक अनुक्रम के शैललक्षण, जीवाश्म तथा आयु पर चर्चा कीजिये । (15 अंक)
Answer approach & key points
Discuss demands a comprehensive treatment with critical interlinking of concepts. Structure: Part (a) – define porosity-permeability-hydraulic conductivity relationships with Darcy's law application and step-by-step calculation; Part (b) – describe Glossopteris, Gangamopteris, Vertebraria, Noeggerathiopsis with diagrams and Gondwana dispersal significance; Part (c) – trace Spiti Basin Palaeozoic sequence from Tal Group through Permian with litho-bio-chronostratigraphic integration. Conclude with unified thematic synthesis on Gondwana basin evolution.
Clear distinction between porosity (void space), permeability (flow capacity) and hydraulic conductivity (K = kρg/μ), with Darcy's law application for K calculation yielding correct value ~0.024 m/s
Accurate diagrams of Glossopteris, Gangamopteris, Vertebraria showing reticulate venation, and Noeggerathiopsis with fan-shaped leaves; linking to Gondwanaland reconstruction via identical flora across India-Australia-Africa-Antarctica
Spiti Basin Palaeozoic succession: Tal Group (Cambrian-Ordovician quartzite-shale with archaeocyathids/trilobites), Thango Group (Silurian-Devonian limestone with brachiopods/corals), and Permian (Productus limestone, Umaria marine bed)
Quantitative derivation showing Q = KA(h/L), proper unit conversion (cm to m), and dimensional consistency in final K value
Economic significance: Lower Gondwana coal-bearing formations (Damuda Series) as India's prime coal resource; Spiti Basin hydrocarbon potential and strategic metal mineralization