All 8 questions from UPSC Civil Services Mains Geology 2024 Paper I (400 marks total). Every stem reproduced in full, with directive-word analysis, marks, word limits, and answer-approach pointers.
50M150wCompulsorydiscussOrigin of Earth, rock structures, remote sensing, soil formation, dip and strike
Answer the following questions in about 150 words each:
(a) Discuss two widely accepted theories of origin of the earth. Elucidate the position of all planets within the solar system and write the important facts of the earth. (10 marks)
(b) What are the planar and linear structures of a rock? Discuss the genesis of boudins. (10 marks)
(c) Discuss the applications of remote sensing in Geology. (10 marks)
(d) Discuss the process of soil formation. (10 marks)
(e) Define dip of a rock bed. What is true dip and apparent dip? Find the strike direction of a bed which dips 30° towards North 30° East. (10 marks)
हिंदी में पढ़ें
निम्नलिखित प्रत्येक प्रश्न का लगभग 150 शब्दों में उत्तर दीजिए :
(a) पृथ्वी की उत्पत्ति के संबंध में व्यापक रूप से स्वीकार्य दो सिद्धांतों का वर्णन कीजिए। सभी ग्रहों की सौरमंडल में अवस्थिति दर्शाते हुए पृथ्वी के प्रमुख तथ्यों को लिखिए। (10 अंक)
(b) शैल की तलीय एवं रेखीय संरचनाएं क्या हैं? बाउडिन के उद्भव का वर्णन कीजिए। (10 अंक)
(c) भूगर्भ-विज्ञान में सुदूर संवेदन के अनुप्रयोगों का वर्णन कीजिए। (10 अंक)
(d) मृदा निर्माण की प्रक्रिया का वर्णन कीजिए। (10 अंक)
(e) शैलतल की नति को परिभाषित कीजिए। वास्तविक नति एवं आभासी नति क्या है? एक तल जिसकी नति 30°; उत्तर 30° पूर्व को है, के नतिलम्ब की दिशा ज्ञात कीजिए। (10 अंक)
Answer approach & key points
(a) discuss: intro > 3-4 dimensions > example > balanced close | (b) describe: define > structure or process in order > labelled diagram > significance | (c) discuss: intro > 3-4 dimensions > example > balanced close | (d) discuss: intro > 3-4 dimensions > example > balanced close | (e) calculate: given > formula > substitution > result with units > interpretation Full marks: Precise definitions, correct calculations, named Indian examples, clear diagrams.
Nebular hypothesis (Kant 1755, Laplace 1796) and its modern solar-nebula form
Planetesimal/accretion theory: Chamberlin–Moulton (1905) and modern accretion of planetesimals in the nebular disc (Safronov)
Order of planets: Mercury to Neptune; terrestrial vs Jovian division with the asteroid belt between Mars and Jupiter
Earth facts: third planet, ~1 AU, age ~4.54 Ga, mean radius ~6,371 km, density ~5.51 g/cm³ (highest), ~71% water, magnetic field, plate tectonics, life
Linear structures: fold axes/hinges, mineral and stretching lineation, intersection lineation, mullions, rods
Boudin genesis: competence contrast; extension parallel to a competent layer (shortening normal to it) causes necking and separation, matrix flows into necks
Types: pinch-and-swell, rectangular/lenticular boudins, chocolate-tablet boudinage; use as strain indicator
Principle: EM spectrum, spectral signatures, passive and active (SAR) sensors
Applications: lithological mapping, structural/lineament mapping, mineral exploration via alteration minerals (ASTER SWIR, hyperspectral)
Hazards and environment: landslides, earthquakes (InSAR), glaciers, coastal change
Groundwater and engineering geology; Indian satellites and agencies (ISRO, GSI, NRSC)
Weathering of parent material: physical, chemical, biological
(a) Discuss the intensity and magnitude scale commonly used to assess seismic damage. Write a note on the global distribution pattern of earthquake. Mark the different seismic zones of India on the given map and discuss about them. (20 marks)
(b) Discuss in detail the ideas of geomorphic cycle proposed by Davis and Penck. (15 marks)
(c) What do contours represent in a toposheet? How do the contour lines help to identify the different geomorphic features of an area? Explain with neat diagrams. (15 marks)
हिंदी में पढ़ें
(a) भूकंपीय क्षति के आकलन में आमतौर पर प्रयुक्त होने वाली तीव्रता मापनी एवं परिमाण मापनी का वर्णन कीजिए। भूकंप के वैश्विक वितरण विन्यास पर एक टिप्पणी लिखिए। भारत के विभिन्न भूकंपीय मंडलों को दिए हुए मानचित्र पर दर्शाते हुए उन पर चर्चा कीजिए। (20 अंक)
(b) डेविस तथा पैंक द्वारा प्रस्तावित भू-आकृतिक चक्र की अवधारणा का विस्तार से वर्णन कीजिए। (15 अंक)
(c) टोपोशीट पर समोचरेखा क्या दर्शाती हैं? समोचरेखा कैसे किसी क्षेत्र के विभिन्न भू-आकृतिक लक्षणों की पहचान करने में सहायक होती हैं? स्वच्छ चित्र सहित व्याख्या कीजिए। (15 अंक)
Answer approach & key points
Framework: Geology, Paper 1. (a) discuss: intro > 3-4 dimensions > example > balanced close | (b) discuss: intro > 3-4 dimensions > example > balanced close | (c) explain: definition/context > points in order > small example > short close Full marks: Comprehensive, accurate, with detailed diagrams and Indian examples.
Magnitude (ML, mb, Ms, Mw; logarithmic; ~32× energy per unit) vs intensity (MM, MSK-64, EMS-98; site-specific, damage-based; isoseismals)
Global belts: Circum-Pacific (~80%), Alpide (~15–17%), mid-ocean ridges, intraplate/rift zones, with plate-tectonic explanation
India's zones per IS 1893 (Part 1): 2016 — II to V with zone factors and correct regional placement
Map marking of zones with example earthquakes (Assam 1950, Koyna 1967, Latur 1993, Bhuj 2001)
Davis: structure–process–stage, rapid uplift then stillstand, youth–maturity–old age, peneplain and monadnocks, slope decline, rejuvenation
Penck: simultaneous uplift and denudation, waxing/uniform/waning development giving convex/straight/concave slopes, slope replacement and parallel retreat, Primärrumpf, Endrumpf, Piedmonttreppen
Comparison: time-dependent vs time-independent; slope decline vs slope replacement
Critique of both and relevance today
Definition, contour interval, horizontal equivalent, relation to slope; SOI toposheet conventions
Slope types from spacing (steep, gentle, uniform, concave, convex)
Landforms: hill, plateau, depression, valley (V upstream), spur (V downslope), ridge, saddle, cliff, waterfall, terraces
(a) Discuss in detail, with diagrams, the landforms and features resulting from deposition by rivers. (20 marks)
(b) Describe the characteristics of Indian remote sensing satellites. (15 marks)
(c) Diagrammatically explain the formation of normal fault, strike-slip fault and thrust fault with the help of stress ellipsoid. (15 marks)
हिंदी में पढ़ें
(a) नदी निक्षेपण द्वारा निर्मित भू-आकृतियों एवं अभिलक्षणों का चित्र सहित विस्तृत वर्णन कीजिए। (20 अंक)
(b) भारतीय सूदूर संवेदन उपग्रहों की विशेषताओं का वर्णन कीजिए। (15 अंक)
(c) प्रतिबल दीर्घवृत्तज की सहायता से सामान्य भ्रंश, नतिलम्ब सर्पण भ्रंश तथा क्षेप भ्रंश के निर्माण की सचित्र व्याख्या कीजिए। (15 अंक)
Answer approach & key points
Framework: Geology, Paper 1. (a) discuss: intro > 3-4 dimensions > example > balanced close | (b) describe: define > structure or process in order > labelled diagram > significance | (c) explain: definition/context > points in order > small example > short close Full marks: Comprehensive with accurate diagrams, specific examples, and correct technical terminology.
Controls: fall in competence and capacity, base level, sediment supply
Strike-slip: σ2 vertical, near-vertical plane, horizontal slip; fault-plane solutions (P vertical for normal, T vertical for thrust, N vertical for strike-slip)
(a) Describe fold geometry. Illustrate various types of folds on the basis of their symmetry, orientation of axial plane and the trend of the fold axis. (20 marks)
(b) Describe and illustrate different types of plate boundaries, and explain the mechanism of plate motion. (15 marks)
(c) "At depth of compensation, the pressure generated by all overlying landmass substances on the earth is everywhere equal." Describe the hypotheses which support this statement. (15 marks)
हिंदी में पढ़ें
(a) वलन ज्यामिति पर प्रकाश डालिए। वलन सममिति, अक्षीय तल विन्यास एवं वलन अक्ष की प्रवृत्ति के आधार पर विभिन्न प्रकार के वलनों का सचित्र वर्णन कीजिए। (20 अंक)
(b) विभिन्न प्रकार की प्लेट सीमाओं का सचित्र वर्णन कीजिए तथा प्लेट गतिकीय क्रियाविधि को समझाइए। (15 अंक)
(c) "पृथ्वी पर सभी भूद्रव्यमान पदार्थ द्वारा उत्पन्न दाब प्रतिकार गभीरता पर समग्र समान होता है।" इस कथन की पृष्ठकारक परिकल्पनाओं का वर्णन कीजिए। (15 अंक)
Answer approach & key points
Framework: Geology Paper 1: Define > Process > Field/Petrographic Evidence > Indian Example. (a) describe: define > structure or process in order > labelled diagram > significance | (b) describe: define > structure or process in order > labelled diagram > significance | (c) describe: define > structure or process in order > labelled diagram > significance Full marks: Precise definitions, labelled diagrams, named Indian examples, clear causal chains
Answer the following questions in about 150 words each:
(a) Define species and explain how paleontological species are different from biological species. (10 marks)
(b) Discuss the geological parameters used to subdivide the Dharwar Craton into two subcratons. (10 marks)
(c) Describe the Cretaceous volcanic province in India. (10 marks)
(d) Describe how Darcy's law and Reynolds' number are related to the types of fluid flow in aquifers. (10 marks)
(e) Describe the rehabilitation measures required in landslide-affected area to restore the community and the ecology of the area affected. (10 marks)
हिंदी में पढ़ें
निम्नलिखित प्रत्येक प्रश्न का लगभग 150 शब्दों में उत्तर दीजिए :
(a) प्रजाति को परिभाषित कीजिए तथा स्पष्ट कीजिए कि जीवाश्मिकीय प्रजातियाँ जैविक प्रजातियों से किस प्रकार भिन्न हैं। (10 अंक)
(b) धारवाड़ क्रैटन को दो उप-क्रैटनों में प्रविभाजित करने के लिए उपयोग किए जाने वाले भूवैज्ञानिक मापदंडों पर चर्चा कीजिए। (10 अंक)
(c) भारत में क्रीटेशियस ज्वालामुखी शैलक्षेत्र का वर्णन कीजिए। (10 अंक)
(d) डार्सी नियम तथा रेनॉल्ड्स नम्बर कैसे जलभृत में विभिन्न तरल प्रवाह से सम्बन्धित हैं? वर्णन कीजिए। (10 अंक)
(e) भूस्खलन प्रभावित क्षेत्र में समुदाय और पारिस्थितिकी को बहाल करने के लिए आवश्यक पुनर्वास उपायों पर प्रकाश डालिए। (10 अंक)
Answer approach & key points
Framework: Geology, Paper 1. (a) define: precise definition > the distinguishing feature > one example | (b) discuss: intro > 3-4 dimensions > example > balanced close | (c) describe: define > structure or process in order > labelled diagram > significance | (d) describe: define > structure or process in order > labelled diagram > significance | (e) describe: define > structure or process in order > labelled diagram > significance Full marks: Precise definitions, named Indian examples, and clear causal chains.
Biological species concept (Mayr): interbreeding populations reproductively isolated
Paleospecies defined on morphology: morphospecies, chronospecies within a lineage, time dimension
Problems: incomplete preservation, ontogeny, dimorphism, ecophenotypic variation; population approach (palaeodeme)
Contrast summarised: reproductive isolation vs morphological/stratigraphic criteria
Western vs Eastern Dharwar Craton
Age: WDC older TTG (3.4–3.0 Ga) and Sargur belts vs EDC younger juvenile crust and granitoids (2.7–2.5 Ga)
Greenstone belts: WDC sediment-rich Dharwar Supergroup (Bababudan, Chitradurga) vs EDC volcanic-dominated Kolar–Hutti–Ramagiri belts; structural trends
Boundary: Chitradurga shear zone with the ~2.5 Ga Closepet Granite; geophysical contrasts (thicker WDC crust) and metamorphic grade
Deccan Traps: age ~66 Ma spanning the K–Pg boundary, extent ~500,000 km², thickness >2 km in the Western Ghats
(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 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)
Answer approach & key points
Framework: Geology Paper 1: Define > Process > Field/Petrographic Evidence > Indian Example. (a) explain: definition/context > points in order > small example > short close | (b) describe: define > structure or process in order > labelled diagram > significance | (c) describe: define > structure or process in order > labelled diagram > significance Full marks: Comprehensive, specific, and well-structured with Indian examples and diagrams.
Origin in Africa: Paleocene–Eocene early forms (Eritherium, Phosphatherium, Moeritherium), Oligocene Palaeomastodon/Phiomia
Trends: size increase, columnar limbs, trunk elongation, skull shortening/heightening, tusks from incisors, reduction in tooth number, lophodont to lamellar hypsodont molars, horizontal tooth replacement
Indian Siwalik record (Stegodon, Elephas hysudricus, Palaeoloxodon namadicus) and climatic drivers
Lower Vindhyan (Semri Group: Kajrahat Limestone, Porcellanite, Rohtas/Semri limestones) and Upper Vindhyan (Kaimur, Rewa, Bhander Groups) separated by a major unconformity
Environments: Semri carbonate platform/ramp with volcaniclastic porcellanites; Kaimur–Rewa siliciclastic shelf–deltaic; Bhander tidal-flat, lagoonal carbonates and stromatolites, upper sandstone
Age constraints: Semri ~1.6–1.7 Ga (porcellanite zircon ages), Majhgawan kimberlite ~1.1 Ga cutting Upper Vindhyan, detrital zircon youngest ~1.0 Ga
Debate: Mesoproterozoic vs younger Neoproterozoic age for upper units; fossil and isotope claims
Unconfined, confined (artesian when head is above ground), semi-confined/leaky, perched
Related units: aquitard, aquiclude, aquifuge
Properties: porosity, specific yield vs specific retention, hydraulic conductivity, transmissivity (T = Kb), storativity (S ≈ Sy unconfined; 10⁻⁵–10⁻³ confined, dimensionless)
Indian examples: Bhabar, Indo-Gangetic alluvium, Deccan weathered/fractured basalt, coastal aquifers
50MdiscussStratigraphic analysis, organic-walled microfossils, highway geology in Himalayas
(a) Discuss the merits and limitations of different methods of stratigraphic analysis in brief. Comment on the most suitable method of stratigraphic analysis with justification. (20 marks)
(b) Describe in brief various types of organic-walled microfossils. Add a note on their biostratigraphic and paleogeographic significance. (15 marks)
(c) Describe the types of geological investigation required before construction of a highway in the Himalayas. (15 marks)
हिंदी में पढ़ें
(a) अश्म-स्तरीय विश्लेषण की विभिन्न विधियों के गुण और परिसीमन पर संक्षेप में चर्चा कीजिए। अश्म-स्तरीय विश्लेषण की सबसे उपयुक्त विधि पर औचित्य सहित टिप्पणी कीजिए। (20 अंक)
(b) विभिन्न प्रकार के जैव-भित्ति वाले सूक्ष्मजीवाश्मों का संक्षेप में वर्णन कीजिए। उनके जैव-स्तरीय और पुराभौगोलिक महत्व पर एक टिप्पणी लिखिए। (15 अंक)
(c) हिमालय में राजमार्ग निर्माण से पूर्व आवश्यक भूवैज्ञानिक सर्वेक्षण के प्रकारों का वर्णन कीजिए। (15 अंक)
Answer approach & key points
Framework: Geology Paper 1: Define > Process > Field/Petrographic Evidence > Indian Example. (a) discuss: intro > 3-4 dimensions > example > balanced close | (b) describe: define > structure or process in order > labelled diagram > significance | (c) describe: define > structure or process in order > labelled diagram > significance Full marks: Precise method names, specific Indian examples, clear justification, and detailed hazard analysis.
Principles: superposition, original horizontality, faunal succession, cross-cutting
Lithostratigraphy, biostratigraphy, chronostratigraphy (GSSP), magnetostratigraphy, sequence stratigraphy, chemostratigraphy, event stratigraphy, geochronology — merits and limitations of each
Justification of an integrated approach, with biostratigraphy as the best single method for fossiliferous Phanerozoic rocks and geochronology/chemostratigraphy for Precambrian
Indian examples (Gondwana palynology, Siwalik magnetostratigraphy, Vindhyan age debate)
Types: acritarchs, prasinophytes, chitinozoans, scolecodonts, dinoflagellate cysts, spores and pollen with age ranges
Biostratigraphic value: rapid evolution, abundance, resistance to acid preparation, use in cuttings and subsurface
(a) Explain the concept of drainage basin morphometry. How do morphometric parameters influence the groundwater conditions of an area? (20 marks)
(b) Discuss various modes of preservation of fossils. (15 marks)
(c) Discuss the evolution of the Himalayas. Illustrate your answer with suitable labelled sketches. (15 marks)
हिंदी में पढ़ें
(a) अपवाह क्षेत्री आकृतिकी (मॉर्फोमीट्री) की अवधारणा की व्याख्या कीजिए। बताइए कि कैसे आकृतिकीय पैरामीटर किसी क्षेत्र की भूजल परिस्थिति को प्रभावित करते हैं। (20 अंक)
(b) जीवाश्मों के संरक्षण की विभिन्न क्रियाविधियों पर प्रकाश डालिए। (15 अंक)
(c) हिमालय के उद्भव का वर्णन कीजिए। उपयुक्त नामांकित चित्र सहित अपना उत्तर स्पष्ट कीजिए। (15 अंक)
Answer approach & key points
Framework: Geology Paper 1: Define > Process > Field/Petrographic Evidence > Indian Example. (a) explain: definition/context > points in order > small example > short close | (b) discuss: intro > 3-4 dimensions > example > balanced close | (c) discuss: intro > 3-4 dimensions > example > balanced close Full marks: Comprehensive, well-structured, with precise terminology, Indian examples, and clear sketches.
Concept and parameters: linear (order, length, Rb), areal (Dd, Fs, Rf, Re, Rc, Lg), relief (H, Rh, Rn); Horton and Strahler laws
Drainage density and stream frequency as indicators of permeability and infiltration
Bifurcation ratio and structural control; basin shape and hydrograph peaks; slope and relief controls on runoff vs recharge
Application: prioritising recharge zones and watershed development, GIS/remote sensing extraction
Body vs trace fossils; taphonomic controls (hard parts, rapid burial, anoxia)
Exceptional preservation (Lagerstätten), chemical fossils; Indian examples (Siwalik bones, Gondwana Glossopteris, Deccan intertrappean silicified plants)
Pre-collision: Neotethys subduction under Asia, Andean-type Trans-Himalayan (Ladakh) batholith
Collision ~55–50 Ma; Indus–Tsangpo suture; continued convergence
Tectonic zones and thrusts from north to south: Tethyan Himalaya, STDS, Greater Himalaya, MCT (inverted metamorphism), Lesser Himalaya, MBT, Siwaliks, MFT; southward-propagating sequence and MHT